Patent Publication Number: US-2022231236-A1

Title: Organic Compound, Organic Light Emitting Diode and Organic Light Emitting Device Having the Compound

Description:
TECHNICAL FIELD 
     The present disclosure relates to an organic compound, and more specifically, to an organic compound having excellent luminous efficiency and luminous lifespan and an organic light emitting diode and an organic light emitting device including the organic compound. 
     BACKGROUND ART 
     An organic light emitting diode (OLED) among a flat display device used widely has come into the spotlight as a display device replacing rapidly a liquid crystal display device (LCD). The OLED can be formed as a thin organic film less than 2000 Å and can implement unidirectional or bidirectional images by electrode configurations. Also, the OLED can be formed even on a flexible transparent substrate such as a plastic substrate so that a flexible or a foldable display device can be realized with ease using the OLED. In addition, the OLED can be driven at a lower voltage and the OLED has excellent high color purity compared to the LCD. 
     Since fluorescent material uses only singlet exciton energy in the luminous process, the related art fluorescent material shows low luminous efficiency. On the contrary, phosphorescent material can show high luminous efficiency since it uses triplet exciton energy as well as singlet exciton energy in the luminous process. However, metal complex, representative phosphorescent material, has short luminous lifespan for commercial use. Particularly, the blue luminous materials have shown unsatisfactory luminous lifespan and luminous efficiency compared to other luminous materials. Therefore, there remains a need to develop a new compound that can enhance luminous efficiency and luminous lifespan. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     Accordingly, embodiments of the present disclosure are directed to an organic compound, an organic light emitting diode and an organic light emitting device have substantially obviates one or more of the problems due to the limitations and disadvantages of the related art. 
     An object of the present disclosure is to provide an organic compound having excellent luminous efficiency and luminous lifespan, an organic light emitting diode and an organic light emitting device including the organic compound. 
     Another object of the present disclosure is to provide an organic compound having excellent durable properties to external stress such as heat with minimizing the utilization of expensive deuterium, an organic light emitting diode and an organic light emitting device including the organic compound. 
     Addition features and aspect will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the inventive concepts provided herein. Other features and aspect of the inventive concept can be realized and attained by the structure practically pointed out in the written description, or derivatives therefrom, and the claims hereof as well as the appended drawings. 
     Solution to Problem 
     The achieve these and other aspects of the inventive concepts, as embodied and broadly descried, in one aspect, the present disclosure provides an organic compound having the following structure of Formula 1: 
     
       
         
         
             
             
         
       
     
     wherein Ar 1  is C 6 -C 30  arylene or C 3 -C 30  hetero arylene, each of the C 6 -C 30  arylene or the C 3 -C 30  hetero arylene is independently unsubstituted or substituted with at least one of a C 1 -C 10  alkyl group, a C 6 -C 20  aryl group and a C 3 -C 20  hetero aryl group; A has the following structure of Formula 2; B has the following structure of Formula 3; and m is 0 or 1; 
     
       
         
         
             
             
         
       
     
     wherein each of R 1  to R 3  is independently protium, halogen, a cyano group, a C 1 -C 20  alkyl group, a C 1 -C 20  halo alkyl group, a C 1 -C 20  alkoxy group, a C 1 -C 20  alkyl amino group, a C 5 -C 30  alicyclic group, a C 4 -C 30  hetero alicyclic group, a C 6 -C 30  aromatic group or a C 3 -C 30  hetero aromatic group, the C 1 -C 20  alkoxy group is unsubstituted or substituted with halogen, and each of the C 6 -C 30  aromatic group and the C 3 -C 30  hetero aromatic group is independently unsubstituted or substituted with at least one of a C 1 -C 20  alkyl group, a C 6 -C 20  aromatic group and a C 3 -C 20  hetero aromatic group; each of a, b and c is a number of a substituent, a is an integer of 0 to 3, each of b and c is independently an integer of 0 to 2; 
     
       
         
         
             
             
         
       
     
     wherein X is O, S or —O═S═O; each of R 11  and R 12  is independently protium, deuterium, halogen, a cyano group, a C 1 -C 20  alkyl group, a C 1 -C 20  halo alkyl group, a C 1 -C 20  alkoxy group, a C 1 -C 20  alkyl amino group, a C 5 -C 30  alicyclic group, a C 4 -C 30  hetero alicyclic group, a C 6 -C 30  aromatic group or a C 3 -C 30  hetero aromatic group, each of the C 6 -C 30  aromatic group and the C 3 -C 30  hetero aromatic group is independently unsubstituted or substituted with at least one of a C 1 -C 20  alkyl group, a C 6 -C 20  aromatic group and a C 3 -C 20  hetero aromatic group, at least one of R 11  and R 12  is deuterium, R 11  is identical to or different from each other when d is two or more and R 12  is identical to or different from each other when e is two or more; each of d and e is a number of a substituent, d is an integer of 0 to 3 and e is an integer of 0 to 4, at least one of d and e is not 0. 
     In another aspect, the present disclosure provides an organic light emitting diode, which comprises a first electrode; a second electrode facing the first electrode; and an emissive layer disposed between the first electrode and the second electrode, wherein the emissive layer includes at least one emitting material layer and at least one electron transport layer disposed between the at least one emitting material layer and the second electrode, and wherein the at least one electron transport layer includes an organic compound having the structure of Formula 1. 
     In still another aspect, the present disclosure provides an organic light emitting diode which comprises a first electrode; a second electrode; and an emissive layer disposed between the first electrode and the second electrode, wherein the emissive layer includes a first emitting part disposed between the first electrode and the second electrode, a second emitting part disposed between the first emitting part and the second electrode and a charge generation layer disposed between the first emitting part and the second emitting part, wherein the first emitting part includes a first emitting material layer and a first electron transport layer disposed between the first emitting material layer and the charge generation layer, and wherein at least one of the first electron transport layer and the charge generation layer includes an organic compound having the following structure of Formula 1. 
     In further still another aspect, the present disclosure provides an organic light emitting device which comprises a substrate; and the organic light emitting diode over the substrate. 
     In the organic light emitting device, the substrate may define a red pixel region, a green pixel region and a blue pixel region and the organic light emitting diode may be located correspondingly to the red pixel region, the green pixel region and the blue pixel region, and the organic light emitting device may further include a color filter layer disposed between the substrate and the organic light emitting diode or over the organic light emitting diode correspondingly to the red pixel region, the green pixel region and the blue pixel region. 
     In the organic light emitting device, the substrate may define a red pixel region, a green pixel region and a blue pixel region and the organic light emitting diode may be located correspondingly to the red pixel region, the green pixel region and the blue pixel region, and the organic light emitting device may further include a color conversion layer disposed between the substrate and the organic light emitting diode or over the organic light emitting diode correspondingly to the red pixel region and the green pixel region. 
     Advantageous Effects of Invention 
     The organic compound of the present disclosure is deuterated in a specific moiety. Since deuterium has good resistance to external stress such as heat, the organic compound where only a specific moiety that can easily undergo thermal decomposition is deuterated shows excellent luminous efficiency and luminous lifespan similar to a compound where all protium atoms within the entire molecule are substituted with deuterium atoms. An organic light emitting diode (OLED) and an organic light emitting device having improved luminous efficiency and luminous lifespan can be manufactured by introducing the organic compound substituted deuterium in only the specific moiety without substituting with deuterium atoms in the entire molecule. It is possible to have an advantage of economically utilizing expensive deuterium, and thereby reducing the manufacturing cost of the light emitting diode with great. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the present disclosure, are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain principles of the disclosure. 
         FIG. 1  is a schematic circuit diagram illustrating an organic light emitting display device in accordance with the present disclosure. 
         FIG. 2  is a schematic cross-sectional view illustrating an organic light emitting display device as an example of an organic light emitting device in accordance with an exemplary aspect of the present disclosure. 
         FIG. 3  is a schematic cross-sectional view illustrating an organic light emitting diode having a single emitting part in accordance with one exemplary aspect of the present disclosure. 
         FIG. 4  is a schematic cross-sectional view illustrating an organic light emitting diode having two emitting parts in accordance with another exemplary aspect of the present disclosure. 
         FIG. 5  is a schematic cross-sectional view illustrating an organic light emitting display device as an example of an organic light emitting device in accordance with another exemplary aspect of the present disclosure. 
         FIG. 6  is a schematic cross-sectional view illustrating an organic light emitting diode having three emitting parts in accordance with still another exemplary aspect of the present disclosure. 
         FIG. 7  is a schematic cross-sectional view illustrating an organic light emitting display device as an example of an organic light emitting device in accordance with still another exemplary aspect of the present disclosure. 
     
    
    
     MODE FOR INVENTION 
     Reference will now be made in detail to aspects of the disclosure, examples of which are illustrated in the accompanying drawings. 
     An emissive layer of an organic light emitting diode (OLED) includes an organic compound having proper energy level and excellent charge mobility property. The present disclosure relates to an organic compound that includes a phenanthroline moiety having excellent electron transport property and electron injection property and at least one nuclear atom within a fused hetero aromatic moiety including O and/or S is deuterated. The organic compound of the present disclosure may have the following structure of Formula 1: 
     
       
         
         
             
             
         
       
     
     wherein Ar 1  is C 6 -C 30  arylene or C 3 -C 30  hetero arylene, each of the C 6 -C 30  arylene or the C 3 -C 30  hetero arylene is independently unsubstituted or substituted with at least one of a C 1 -C 10  alkyl group, a C 6 -C 20  aryl group and a C 3 -C 20  hetero aryl group; A has the following structure of Formula 2; B has the following structure of Formula 3; and m is 0 or 1; 
     
       
         
         
             
             
         
       
     
     wherein each of R 1  to R 3  is independently protium, halogen, a cyano group, a C 1 -C 20  alkyl group, a C 1 -C 20  halo alkyl group, a C 1 -C 20  alkoxy group, a C 1 -C 20  alkyl amino group, a C 5 -C 30  alicyclic group, a C 4 -C 30  hetero alicyclic group, a C 6 -C 30  aromatic group or a C 3 -C 30  hetero aromatic group, the C 1 -C 20  alkoxy group is unsubstituted or substituted with halogen, and each of the C 6 -C 30  aromatic group and the C 3 -C 30  hetero aromatic group is independently unsubstituted or substituted with at least one of a C 1 -C 20  alkyl group, a C 6 -C 20  aromatic group and a C 3 -C 20  hetero aromatic group; each of a, b and c is a number of a substituent, a is an integer of 0 to 3, each of b and c is independently an integer of 0 to 2; 
     
       
         
         
             
             
         
       
     
     wherein X is O, S or —O═S═O; each of R 11  and R 12  is independently protium, deuterium, halogen, a cyano group, a C 1 -C 20  alkyl group, a C 1 -C 20  halo alkyl group, a C 1 -C 20  alkoxy group, a C 1 -C 20  alkyl amino group, a C 5 -C 30  alicyclic group, a C 4 -C 30  hetero alicyclic group, a C 6 -C 30  aromatic group or a C 3 -C 30  hetero aromatic group, each of the C 6 -C 30  aromatic group and the C 3 -C 30  hetero aromatic group is independently unsubstituted or substituted with at least one of a C 1 -C 20  alkyl group, a C 6 -C 20  aromatic group and a C 3 -C 20  hetero aromatic group, at least one of R 11  and R 12  is deuterium, R 11  is identical to or different from each other when d is two or more and R 11  is identical to or different from each other when e is two or more; each of d and e is a number of a substituent, d is an integer of 0 to 3 and e is an integer of 0 to 4, at least one of d and e is not 0. 
     As used herein, substituent in the term “substituted” comprises, but is not limited to, deuterium, unsubstituted or deuterium or halogen-substituted C 1 -C 20  alkyl, unsubstituted or deuterium or halogen-substituted C 1 -C 20  alkoxy, halogen, cyano, —CF 3 , a hydroxyl group, a carboxylic group, a carbonyl group, an amino group, a C 1 -C 10  alkyl amino group, a C 6 -C 30  aryl amino group, a C 3 -C 30  hetero aryl amino group, a C 6 -C 30  aryl group, a C 3 -C 30  hetero aryl group, a nitro group, a hydrazyl group, a sulfonate group, a C 1 -C 20  alkyl silyl group, a C 6 -C 30  aryl silyl group and a C 3 -C 30  hetero aryl silyl group. 
     As used herein, the term ‘hetero” in such as “hetero aromatic group”, “hetero alicyclic group”, “hetero aryl group”, “hetero aryl alkyl group”, “hetero aryloxy group”, “hetero aryl amino group” and the like means that at least one carbon atom, for example 1-5 carbons atoms, constituting an alicyclic group or ring or an aromatic group or ring is substituted with at least one hetero atom selected from the group consisting of N, O, S, P and combination thereof. 
     In one exemplary aspect, when each of R 1  to R 3  in Formula 2 and each of R 11  and R 12  in Formula 3 is independently a C 6 -C 30  aromatic group, each of R 1  to R 3 , R 11  and R 12  may comprise independently, but is not limited to, a C 6 -C 30  aryl group, a C 7 -C 30  aryl alkyl group, a C 6 -C 30  aryloxy group and a C 6 -C 30  aryl amino group. As an example, when each of Ru to R 3 , R 11  and R 12  is independently a C 6 -C 30  aryl group, each of R 1  to R 3 , R 11  and R 12  may independently comprise, but is not limited to, an unfused or fused aryl group such as phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, pentalenyl, indenyl, indeno-indenyl, heptalenyl, biphenylenyl, indacenyl, phenalenyl, phenanthrenyl, benzophenanthrenyl, dibenzophenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, triphenylenyl, chrysenyl, tetraphenylenyl, tetracenyl, pleiadenyl, picenyl, pentaphenylenyl, pentacenyl, fluorenyl, indeno-fluorenyl and spiro-fluorenyl. 
     Alternatively, when each of R 1  to R 3  in Formula 2 and each of R 11  and R 12  in Formula 3 is independently a C 3 -C 30  hetero aromatic group, each of R 1  to R 3 , R 11  and R 12  may comprise independently, but is not limited to, a C 3 -C 30  hetero aryl group, a C 4 -C 30  hetero aryl alkyl group, a C 3 -C 30  hetero aryl oxy group and a C 3 -C 30  hetero aryl amino group. As an example, when each of R 1  to R 3 , R 11  and R 12  R 1  to R 6  is independently a C 3 -C 30  hetero aryl group, each of R 1  to R 3 , R 11  and R 12  R 1  to R 6  may independently comprise, but is not limited to, an unfused or fused hetero aryl group such as pyrrolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetrazinyl, imidazolyl, pyrazolyl, indolyl, iso-indolyl, indazolyl, indolizinyl, pyrrolizinyl, carbazolyl, benzocarbazolyl, dibenzocarbazolyl, indolo-carbazolyl, indeno-carbazolyl, benzofuro-carbazolyl, benzothieno-carbazolyl, carbolinyl, quinolinyl, iso-quinolinyl, phthlazinyl, quinoxalinyl, cinnolinyl, quinazolinyl, quinolizinyl, purinyl, benzoquinolinyl, benzoiso-quinolinyl, benzoquinazolinyl, benzoquinoxalinyl, acridinyl, phenazinyl, phenoxazinyl, phenothiazinyl, phenanthrolinyl, perimidinyl, phenanthridinyl, pteridinyl, naphthyridinyl, furanyl, pyranyl, oxazinyl, oxazolyl, oxadiazolyl, triazolyl, dioxinyl, benzofuranyl, dibenzofuranyl, thiopyranyl, xanthenyl, chromenyl, iso-chromenyl, thioazinyl, thiophenyl, benzothiophenyl, dibenzothiophenyl, difuro-pyrazinyl, benzofuro-dibenzofuranyl, benzothieno-benzothiophenyl, benzothieno-dibenzothiophenyl, benzothieno-benzofuranyl, benzothieno-dibenzofuranyl, xanthene-linked spiro acridinyl, dihydroacridinyl substituted with at least one C 1 -C 10  alkyl and N-substituted spiro fluorenyl. 
     As an example, when each of R 1  to R 3 , R 11  and R 12  is independently the aromatic group or the hetero aromatic group, each of R 1  to R 3 , R 11  and R 12  may comprise independently, but is not limited to, phenyl, biphenyl, pyrrolyl, triazinyl, imidazolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, benzofuranyl, dibenzofuranyl, thiophenyl, benzothiophenyl, dibenzothiophenyl and carbazolyl. 
     When Ar 1  is C 6 -C 30  arylene, Ar 1  may comprise, but is not limited to, phenylene, biphenylene, terphenylene, tetraphenylene, indenylene, napthylene, azulenylene, indacenylene, acenaphthylene, fluorenylene, spiro-fluorenylene, phenalenylene, phenanthrenylene, anthracenylene, fluoranthenylene, triphenylenylene, naphthacenylene, picenylene, perylenylene, pentaphenylene and hexacenylene, each of which may be unsubstituted or substituted with at least one of a C 1 -C 10  alkyl group, a C 6 -C 20  aryl group and a C 3 -C 20  hetero aryl group 
     Alternatively, when Ar 1  is C 3 -C 30  hetero arylene, Ar 1  may comprise, but is not limited to, pyrrolylene, imidazolylene, pyrazolylene, pyridinylene, pyrazinylene, pyrimidinylene, pyridazinylene, isoindolylene, indolylene, indazolylene, purinylene, quinolinylene, isoquinolinylene, benzoquinolinylene, phthalazinylene, naphthyridinylene, quinoxalinylene, quinazolinylene, benzoisoquinolinylene, benzoquinazolinylene, benzoquinoxalinylene, cinnolinylene, phenanthridinylene, acridinylene, phenanthrolinylene, phenazinylene, benzoxazolylene, benzimidazolylene, furanylene, benzofuranylene, thiophenylene, benzothiophenylene, thiazolylene, isothiazolylene, benzothiazolylene, isoxazolylene, oxazolylene, triazolylene, tetrazolylene, oxadiazolylene, triazinylene, dibenzofuranylene, benzofurodibenzofuranylene, benzothienobenzofuranylene, benzothienodibenzofurnalylene, dibenzothiophenylene, benzothienobenzothiophenylene, benzothienodibenzothiophenylene, carbazolylene, benzocarbazolylene, dibenzocarbazolylene, indolocarbazolylene, indencocarbazolylene, benzofurocarbazolyene, benzothienocarbazolylene, imidazopyrimidinylene and imidazopyridinylene, each of which may be unsubstituted or substituted with at least one of a C 1 -C 10  alkyl group, a C 6 -C 20  aryl group and a C 3 -C 20  hetero aryl group 
     In one exemplary aspect, when the number of the aromatic and/or the hetero aromatic ring constituting Ar 1  is becomes larger, the conjugated structure in the whole organic molecules becomes too long, and thus, the organic compound may have too much narrow energy level bandgap. Therefore, Ar 1  may have one or two aromatic and/or hetero aromatic ring, for example, one aromatic and/or hetero aromatic ring. With regard to charge injection and charge mobility property, Ar 1  may be a 5-membered ring, 6-membered ring or a 7-membered ring, for example, a 6-membered ring. For example, Ar 1  may comprise, but is not limited to, phenylene, biphenylene, pyrrolylene, imidazolylene, pyrazolylene, pyridinylene, pyrazinylene, pyrimidinylene, pyridazinylene, furanylene and thiophenylene. 
     Since the organic compound defined by Formulae 1 to 3 includes a phenanthroline moiety, that is, Formula 2, including nitrogen atoms with enough electrons, the organic compound has excellent electron transport property. In addition, the nitrogen atoms of the phenanthroline moiety can be combined with an alkali metal and/or an alkaline earth metal to form a gap state. 
     In addition, the organic compound includes a fused hetero aromatic moiety, that is, Formula 3, linked to the phenanthroline moiety directly or through a liner moiety, that is, Ar moiety. Since the organic compound includes the fused hetero aromatic moiety with rigid chemical conformation, the organic compound has improved thermal stability. 
     At least one of the nuclear carbon atoms constituting the fused hetero aromatic moiety is deuterated. Hydrogen atom of the fused hetero aromatic moiety is positioned adjacently to oxygen or sulfur atom with relatively high electron affinity. Accordingly, the hydrogen atom linked to the nuclear atoms constituting the fused hetero aromatic moiety has high acidity. 
     Generally, when an organic compound is deuterated, unsubstitued compound with the entire carbon skeleton of the molecule is reacted with deuterium raw material such as d 6 -benzene or D 2 O using acid or base catalysts. However, in this case, a large amount of expensive deuterium raw materials must be used, and results in environmental pollution problem in the deuteration of the whole molecule. 
     On the contrary, it is possible to delay the dissociation of deuterium from the molecule and improve the electrochemical stability of the molecule by only substituting for at least one protium, which has relatively high acidity, linked to the nuclear carbon atoms constituting the fused hetero aromatic moiety, rather than substituting all the protium within the entire molecule. Accordingly, the organic compound where at least one protium linked to the nuclear carbon atoms constituting the fused hetero aromatic moiety can secure as high luminous efficiency and luminous lifespan as an organic compound where all the nuclear carbon atoms of the aromatic and hetero aromatic rings constituting the skeleton of entire molecule. 
     In one exemplary aspect, Ar 1  is a divalent aromatic bridging group or a divalent hetero aromatic bridging group, Ar 1  may be selected from, but is not limited to, the following moieties: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
      In another exemplary aspect, A in Formula 1 of a phenanthroline moiety having electron transport property, may be selected from, but is not limited to, the following moieties 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In still another exemplary aspect, B in Formula 1 of the fused hetero aromatic moiety where at least one protium linked to the nuclear carbon atoms may be selected from, but is not limited to, the following moieties: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
      As an example, the organic compound having the structure of Formula 1 may be selected from, but is not limited to, the following compounds having the structure of Formula 4: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     Organic Light Emitting Diode and Organic Light Emitting Device 
     Since the organic compound having the structure of Formulae 1 to 4 has excellent electron transport property and electron injection property, it can be applied into an electron transport layer and/or a charge generation layer of an organic light emitting diode (OLED). The OLED may be applied to an organic light emitting device such as an organic light emitting display device and an organic light emitting illumination device. An organic light emitting display device including the OLED will be explained. 
       FIG. 1  is a schematic circuit diagram illustrating an organic light emitting display device in accordance with present disclosure. As illustrated in  FIG. 1 , a gate line GL, a data line DL and power line PL, each of which cross each other to define a pixel region P, in the organic light display device. A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst and an organic light emitting diode D are formed within the pixel region P. The pixel region P may include a red (R) pixel region, a green (G) pixel region and a blue (B) pixel region. 
     The switching thin film transistor Ts is connected to the gate line GL and the data line DL, and the driving thin film transistor Td and the storage capacitor Cst are connected between the switching thin film transistor Ts and the power line PL. The organic light emitting diode D is connected to the driving thin film transistor Td. When the switching thin film transistor Ts is turned on by a gate signal applied into the gate line GL, a data signal applied into the data line DL is applied into a gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts. 
     The driving thin film transistor Td is turned on by the data signal applied into the gate electrode so that a current proportional to the data signal is supplied from the power line PL to the organic light emitting diode D through the driving thin film transistor Td. And then, the organic light emitting diode D emits light having a luminance proportional to the current flowing through the driving thin film transistor Td. In this case, the storage capacitor Cst is charged with a voltage proportional to the data signal so that the voltage of the gate electrode in the driving thin film transistor Td is kept constant during one frame. Therefore, the organic light emitting display device can display a desired image. 
       FIG. 2  is a schematic cross-sectional view illustrating an organic light emitting display device in accordance with an exemplary aspect of the present disclosure. As illustrated in  FIG. 2 , the organic light emitting display device  100  comprises a substrate  102 , a thin-film transistor Tr over the substrate  102 , and an organic light emitting diode D connected to the thin film transistor Tr. As an example, the substrate  102  defines a red (R) pixel region, a green (G) pixel region and a blue (B) pixel region and the organic light emitting diode D is located in each pixel region. In other words, the organic light emitting diode D, each of which emits red, green or blue light, is located correspondingly in the red (R) pixel region, the green (G) pixel region and the blue (B) pixel region. As an example, the OLED D may be located in the blue (B) pixel region. 
     The substrate  102  may include, but is not limited to, glass, thin flexible material and/or polymer plastics. For example, the flexible material may be selected from the group, but is not limited to, polyimide (PI), polyethersulfone (PES), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC) and combination thereof. The substrate  102 , over which the thin film transistor Tr and the organic light emitting diode D are arranged, forms an array substrate. 
     A buffer layer  106  may be disposed over the substrate  102 , and the thin film transistor Tr is disposed over the buffer layer  106 . The buffer layer  106  may be omitted. 
     A semiconductor layer  110  is disposed over the buffer layer  106 . In one exemplary aspect, the semiconductor layer  110  may include, but is not limited to, oxide semiconductor materials. In this case, a light-shield pattern may be disposed under the semiconductor layer  110 , and the light-shield pattern can prevent light from being incident toward the semiconductor layer  110 , and thereby, preventing the semiconductor layer  110  from being deteriorated by the light. Alternatively, the semiconductor layer  110  may include polycrystalline silicon. In this case, opposite edges of the semiconductor layer  110  may be doped with impurities. 
     A gate insulating layer  120  including an insulating material is disposed on the semiconductor layer  110 . The gate insulating layer  120  may include, but is not limited to, an inorganic insulating material such as silicon oxide (SiO x ) or silicon nitride (SiN x ). 
     A gate electrode  130  made of a conductive material such as a metal is disposed over the gate insulating layer  120  so as to correspond to a center of the semiconductor layer  110 . While the gate insulating layer  120  is disposed over a whole area of the substrate  102  in  FIG. 2 , the gate insulating layer  120  may be patterned identically as the gate electrode  130 . 
     An interlayer insulating layer  140  including an insulating material is disposed on the gate electrode  130  with covering over an entire surface of the substrate  102 . The interlayer insulating layer  140  may include an inorganic insulating material such as silicon oxide (SiO x ) or silicon nitride (SiN x ), or an organic insulating material such as benzocyclobutene or photo-acryl. 
     The interlayer insulating layer  140  has first and second semiconductor layer contact holes  142  and  144  that expose both sides of the semiconductor layer  110 . The first and second semiconductor layer contact holes  142  and  144  are disposed over opposite sides of the gate electrode  130  with spacing apart from the gate electrode  130 . The first and second semiconductor layer contact holes  142  and  144  are formed within the gate insulating layer  120  in  FIG. 2 . Alternatively, the first and second semiconductor layer contact holes  142  and  144  are formed only within the interlayer insulating layer  140  when the gate insulating layer  120  is patterned identically as the gate electrode  130 . 
     A source electrode  152  and a drain electrode  154 , which are made of conductive material such as a metal, are disposed on the interlayer insulating layer  140 . The source electrode  152  and the drain electrode  154  are spaced apart from each other with respect to the gate electrode  130 , and contact both sides of the semiconductor layer  110  through the first and second semiconductor layer contact holes  142  and  144 , respectively. 
     The semiconductor layer  110 , the gate electrode  130 , the source electrode  152  and the drain electrode  154  constitute the thin film transistor Tr, which acts as a driving element. The thin film transistor Tr in  FIG. 2  has a coplanar structure in which the gate electrode  130 , and the source electrode  152  and the drain electrode  154  are disposed over the semiconductor layer  110 . Alternatively, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is disposed under a semiconductor layer and a source and drain electrodes are disposed over the semiconductor layer. In this case, the semiconductor layer may include amorphous silicon. 
     Although not shown in  FIG. 2 , a gate line and a data line, which cross each other to define a pixel region, and a switching element, which is connected to the gate line and the data line, is may be further formed in the pixel region. The switching element is connected to the thin film transistor Tr which is a driving element. In addition, a power line is spaced apart in parallel from the gate line or the data line, and the thin film transistor Tr may further include a storage capacitor configured to constantly keep a voltage of the gate electrode for one frame. 
     A passivation layer  160  is disposed on the source and drain electrodes  152  and  154  with covering the thin film transistor Tr over the whole substrate  102 . The passivation layer  160  has a flat top surface and a drain contact hole  162  that exposes the drain electrode  154  of the thin film transistor Tr. While the drain contact hole  162  is disposed on the second semiconductor layer contact hole  144 , it may be spaced apart from the second semiconductor layer contact hole  144 . 
     The organic light emitting diode (OLED) D includes a first electrode  210  that is disposed on the passivation layer  160  and connected to the drain electrode  154  of the thin film transistor Tr. The organic light emitting diode D further includes an emissive layer  230  and a second electrode  220  each of which is disposed sequentially on the first electrode  210 . 
     The first electrode  210  is disposed in each pixel region. The first electrode  210  may be an anode and include conductive material having relatively high work function value. For example, the first electrode  210  may include, but is not limited to, a transparent conductive oxide (TCO) such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), SnO, ZnO, indium cerium oxide (ICO), aluminum doped zinc oxide (AZO), and the like. 
     In one exemplary aspect, when the organic light emitting display device  100  is a bottom-emission type, the first electrode  201  may have a single-layered structure of the TCO. Alternatively, when the organic light emitting display device  100  is a top-emission type, a reflective electrode or a reflective layer may be disposed under the first electrode  210 . For example, the reflective electrode or the reflective layer may include, but is not limited to, silver (Ag) or aluminum-palladium-copper (APC) alloy. In the OLED D of the top-emission type, the first electrode  210  may have a triple-layered structure of ITO/Ag/ITO or ITO/APC/ITO. 
     In addition, a bank layer  164  is disposed on the passivation layer  160  in order to cover edges of the first electrode  210 . The bank layer  164  exposes a center of the first electrode  210  corresponding to each pixel region. The bank layer  164  may be omitted. 
     An emissive layer  230  is disposed on the first electrode  210 . In one exemplary aspect, the emissive layer  230  may have a multiple-layered structure of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an emitting material layer (EML), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL) and/or a charge generation layer (CGL) (see,  FIGS. 3 and 4 ). In one aspect, the emissive layer  230  may have single emitting part. Alternatively, the emissive layer  230  may have multiple emitting parts to form a tandem structure. 
     In one exemplary aspect, the emissive layer  230  may comprise at least one EML including an anthracene-based host and a boron-based dopant when the OLED D emits blue light. At least one of the ETL and the CGL may include the organic compound having the structure of Formulae 1 to 4. 
     The second electrode  220  is disposed over the substrate  102  above which the emissive layer  230  is disposed. The second electrode  220  may be disposed over a whole display area, and may include a conductive material with a relatively low work function value compared to the first electrode  210 , and may be a cathode. For example, the second electrode  220  may include, but is not limited to, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), alloy thereof or combination thereof such as aluminum-magnesium alloy (Al—Mg) and Ag:Mg. For example, when the second electrode is made of Ag:Mg, Ag and Mg can be admixed with, but is not limited to, a weight ratio of about 5:1 to about 10:1, for example, about 8:1 to about 10:1. When the organic light emitting display device  100  is a top-emission type, the second electrode  220  is thin so as to have light-transmissive (semi-transmissive) property. 
     In addition, an encapsulation film  170  may be disposed over the second electrode  220  in order to prevent outer moisture from penetrating into the organic light emitting diode D. The encapsulation film  170  may have, but is not limited to, a laminated structure of a first inorganic insulating film  172 , an organic insulating film  174  and a second inorganic insulating film  176 . The encapsulation film  170  may be omitted. 
     A polarizing plate may be formed to reduce reflection of external light. For example, the polarizing plate may be a circular polarizing plate. When the organic light emitting display device  100  is a bottom-emission type, the polarizing plate may be disposed under the substrate  102 . Alternatively, when the organic light emitting display device  100  is a top-emission type, the polarizing plate may be disposed over the encapsulation film  170 . In addition, a cover window may be attached to the encapsulation film  170  or the polarizer. In this case, the substrate  110  and the cover window may have a flexible property, thus the organic light emitting display device  100  may be a flexible display device. 
     Now, we will describe the OLED D including the organic compound in more detail.  FIG. 3  is a schematic cross-sectional view illustrating an organic light emitting diode having a single emitting part in accordance with an exemplary embodiment of the present disclosure. As illustrated in  FIG. 3 , the organic light emitting diode (OLED) D1 in accordance with the present disclosure includes first and second electrodes  210  and  220  facing each other and an emissive layer  230  disposed between the first and second electrodes  210  and  220 . The organic light emitting display device  100  includes a red (R) pixel region, a green (G) pixel region and a blue (B) pixel region, and the OLED D1 may be disposed in the blue (B) pixel region. 
     One of the first and second electrodes  210  and  220  is an anode and the other of the first and second electrodes  210  and  220  is a cathode. As an example, the first electrode  210  may be a cathode injecting holes and the second electrode  220  may be a cathode injecting electrons. In addition, one of the first and second electrodes  210  and  220  is a reflective electrode and the other of the first and second electrodes  210  and  220  is a transmissive (semi-transmissive) electrode. As an example, each of the first and second electrodes  210  and  220  may have a thickness of, but is not limited to, about 100 Åto about 2000 Å, for example, about 100 Åto about 1000 Å. 
     The emissive layer  230  includes an EML  340  disposed between the first and second electrodes  210  and  220 . Also, the emissive layer  230  may comprise at least one of an HTL  320  disposed between the first electrode  210  and the EML  340  and an ETL  350  disposed between the second electrode  220  and the EML  340 . In addition, the emissive layer  230  may further comprise at least one of an HIL  310  disposed between the first electrode  210  and the HTL  320  and an EML  360  disposed between the second electrode  220  and the ETL  350 . Alternatively, the emissive layer  230  may further comprise an EBL disposed between the HTL  320  and the EML  340  and/or an HBL  350  disposed between the EML  340  and the ETL  350 . 
     The HIL  310  is disposed between the first electrode  210  and the HTL  320  and improves an interface property between the inorganic first electrode  210  and the organic HTL  320 . In one exemplary embodiment, the HIL  310  may include, but is not limited to, 4,4′4″-Tris(3-methylphenylamino)triphenylamine (MTDATA), 4,4′,4″-Tris(N,N-diphenyl-amino)triphenylamine (NATA), 4,4′ ,4″-Tris(N-(naphthalene-1-yl)-N-phenyl-amino)triphenylamine (1T-NATA), 4,4′,4″-Tris(N-(naphthalene-2-yl)-N-phenyl-amino)triphenylamine (2T-NATA), Copper phthalocyanine (CuPc), Tris(4-carbazoyl-9-yl-phenyl)amine (TCTA), N,N′-Diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4″-diamine (NPB; NPD), 1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile (Dipyrazino[2,3 -f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile; HAT-CN), 1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB), poly(3,4-ethylenedioxythiphene)polystyrene sulfonate (PEDOT/PSS), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), N-(biphenyl-4-yl)-9, 9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, N,N′-diphenyl-N,N′-di[4-(N,N′-diphenyl-amino)phenyl]benzidine (NPNPB) and combination thereof. The HIL  310  may be omitted in compliance of the OLED D1 property. 
     The HTL  320  disposed between the HIL  310  and the EML  340  may include, but is not limited to, N,N′-Diphenyl-N,N′-bis(3-methylphenyl-1,1′-biphenyl-4,4′-diamine (TPD), NPB (NPD), N,N′-bis[4-[bis(3-methylphenyl)amino]phenyl]-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (DNTPD), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), Poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine] (Poly-TPD), Poly [(9, 9-dioctylfluorenyl-2, 7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), 1,1-bis(4-(N,N′-di(p-tolyl)amino)phenyl)cyclohexane (TAPC), 3,5-Di(9H-carbazol-9-yl)-N,N-diphenylaniline (DCDPA), N-(biphenyl-4-yl)-9, 9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)biphenyl-4-amine, N-([1,1′-Biphenyl]-4-yl)-9,9-dimethyl-N-(4-(9-phenl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine and combination thereof. 
     The EML  340  may comprise a host (first host) and a dopant (first dopant) where substantial emission is occurred. The EML  340  may emit red, green and/or blue light. In one exemplary aspect, the EML  340  may emit blue light. 
     When the EML  340  emits blue light, the first host may include an anthracene-based organic compound. As an example, the anthracene-based organic compound may have the following structure of Formula 5: 
     
       
         
         
             
             
         
       
     
     wherein each of R 21  and R 22  is independently protium or deuterium; each of Are and Ar 3  is independently a C 6 -C 30  aryl group or a C 4 -C 30  hetero aryl group; L 1  is a C 6 -C 30  arylene group; each of p and q is a number of deuterium substituent and is independently an integer of 0 to 4; and r is 0 or 1. 
     For example, Ar 2  in Formula 5 may be phenyl or naphthyl, Ar 3  in Formula 5 may be naphthyl, dibenzofuranyl or fused dibenzofuranyl and L 1  in Formula 5 may be phenylene. As an example, the anthracene-based organic compound used as the first host may be selected from, but is not limited to, the following compounds having the structure of Formula 6: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The first dopant emitting blue light may include a boron-based organic compound. The boron-based organic compound may have the following structure of Formula 7: 
     
       
         
         
             
             
         
       
     
     wherein each of R 31  to R 34 , each of R 41  to R 44 , each of R 51  to R 55  and each of R 61  to R 65  is independently selected from the group consisting of protium, deuterium, C 1 -C 10  alkyl, C 6 -C 30  aryl, C 6 -C 30  aryl amino and C 5 -C 30  hetero aryl, R 11  to R 14 , R 21  to R 24 , R 31  to R 35  and R 41  to R 45  may be identical to or different from each other, wherein each of the C 6 -C 30  aryl and the C 5 -C 30  hetero aryl may optionally be substituted with another C 1 -C 10  alkyl, or each of two of R 31  to R 55  and two of R 41  to R 45  may form independently a C 6 -C 10  aromatic ring or a C 5 -C 10  hetero aromatic ring; and R 71  is selected from the group consisting of protium, deuterium, C 1 -C 10  alkyl and C 3 -C 15  cyclo alkyl, C 6 -C 30  aryl and C 5 -C 30  hetero aryl and C 6 -C 30  aryl amino, wherein the C 6 -C 30  aryl amino may be optionally substituted with at least one of another C 1 -C 10  alkyl and another C 6 -C 20  aryl. 
     When the aryl, the hetero aryl and/or the aryl amino, which may be each of R 31  to R 34 , each of R 41  to R 44 , each of R 51  to R 55 , each of R 61  to R 65  and R 71 , is substituted, the substituent may be, but is not limited to, C 1 -C 10  alkyl, for example, C 1 -C 5  alkyl such as methyl, tert-butyl and tert-pentyl. 
     For example, the aryl amino may comprise diphenyl amino and phenyl-naphthyl amino, the aryl may comprise phenyl and naphthyl each of which may be unsubstitued or at least one, for example, one or two C 1 -C 10  alkyls, and the hetero aryl may comprise carbazolyl. The alkyl, which may be each of R 31  to R 34 , each of R 41  to R 44 , each of R 51  to R 55 , each of R 61  to R 65  and R 71 , may comprise C 1 -C 10  alkyl, for example, C 1 -C 5  alkyl such as methyl, ethyl, propyl, butyl (e.g. tert-butyl) and pentyl (e.g. tert-pentyl). As an example, each of the aryl amino, the aryl, the hetero aryl and the alkyl, which may be each of R 31  to R 34 , each of R 41  to R 44 , each of R 51  to R 55 , each of R 61  to R 65  and R 71 , may independently optionally further substituted with deuterium. 
     The aromatic ring or the hetero aromatic ring, which may be formed by each of two of R 31  to R 35  and two of R 41  to R 45 , may comprise, but is not limited to, a benzofuran ring and a benzothiophene ring each of which may be independently unsubstituted or substituted with one to three C 1 -C 5  alkyls. 
     The boron-based organic compound used as the first dopant may be selected from, but is not limited to, the following compounds having the structure of Formula 8: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     For example, the contents of the first dopant in the EML  340  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The ETL  350  provides electrons stably to the EML  340  via facilitate electron transportations. The ETL  350  may include an electron transport material  352  that is the organic compound having the structure of Formulae 1 to 4. 
     Alternatively, the ETL  350  may include an alkali metal and/or an alkaline earth metal doped with the electron transport material  352  that is the organic compound having the structure of Formulae 1 to 4. The alkali metal and the alkaline earth metal as the dopant of the ETL  350  may include, but is not limited to, Li, Na, K, Cs, Mg, Sr, Ba, Ra and combination thereof. The contents of the alkali metal and/or the alkaline earth metal in the ETL  350  may be, but is not limited to, about 1 wt % to about 20 wt %, for example, about 1 wt % to about 5 wt %. 
     The EIL  360  is disposed between the second electrode  220  and the ETL  350 , and can improve physical properties of the second electrode  220  and therefore, can enhance the lifetime of the OLED D1. In one exemplary aspect, the EIL  360  may comprise, but is not limited to, an alkali metal halide or an alkaline earth metal halide such as NaF, LiF, CsF, BaF 2 , MgF 2  and the like, and/or an organic metal compound such as lithium quinolate (Liq), lithium benzoate, sodium stearate, and the like. 
     Alternatively, the EIL  360  may include an alkali metal such as Li, Na and Cs, an alkaline earth metal such as Mg, Sr, Ba and Ra and/or a lanthanide metal such as Yb doped with the alkali metal halide, the alkaline earth metal halide and the organic metal compound. In this case, the alkali metal halide/alkaline earth metal halide/organic compound as the host and the alkali metal/alkaline earth metal/lanthanide metal as the dopant may be admixed with a weight ratio of, but is not limited to, about 4:1 to about 1:4, for example, about 2:1 to about 1:2. 
     Since the organic compound having the structure of Formulae 1 to 4 includes the fused hetero aromatic moiety substituted with at least one deuterium, it has excellent thermal stability. In addition, since the organic compound includes the phenanthroline moiety having relatively electron-rich nitrogen atoms, it has excellent electron transport property. Accordingly, the ETL  340  includes the organic compound having the structure of Formulae 1 to 4 so that the OLED D1 can lower its driving voltage as well as maximize its luminous efficiency and luminous lifespan. 
       FIG. 4  is a schematic cross-sectional view illustrating an organic light emitting diode having two emitting parts in accordance with another exemplary aspect of the present disclosure. As illustrated in  FIG. 4 , the OLED D2 includes first and second electrodes  210  and  220  facing each other and an emissive layer  230 A disposed between the first and second electrodes  210  and  220 . The organic light emitting display device  100  ( FIG. 2 ) includes a red (R) pixel region, a green (G) pixel region and a blue (B) pixel region, and the OLED D2 may be located in any pixel region. For example, the OLED D2 may be located in the blue (B) pixel region. 
     One of the first and second electrodes  210  and  220  is an anode and the other of the first and second electrodes  210  and  220  is a cathode. As an example, the first electrode  210  may be a cathode injecting holes and the second electrode  220  may be a cathode injecting electrons. In addition, one of the first and second electrodes  210  and  220  is a reflective electrode and the other of the first and second electrodes  210  and  220  is a transmissive (semi-transmissive) electrode. 
     The emissive layer  230 A includes a first emitting part  400  and a second emitting part  500  and a charge generation layer (CGL)  470  disposed between the first emitting part  400  and the second emitting part  500 . Accordingly, the first emitting part  400 , the CGL  470  and the second emitting part  500  are sequentially formed over the first electrode  210 . In other words, the first emitting part  400  is disposed between the first electrode  210  and the CGL  470  and the second emitting part  500  is disposed between the second electrode  220  and the CGL  470 . 
     The first emitting part  400  includes a first EML (lower EML, EML1)  440 . The first emitting part  400  may further include at least one of an HIL  410  disposed between the first electrode  210  and the EML1  440 , a first HTL (lower HTL, HTL1)  420  disposed between the HIL  410  and the EML1  440  and a first ETL (lower ETL, ETL1)  450  disposed between the EML1  440  and the CGL  470 . Alternatively, the first emitting part  400  may further include a first EBL (lower EBL, EBL1) disposed between the HTL1  420  and the EML1  440 . 
     The second emitting part  500  includes a second EML (upper EML, EML2)  540 . The second emitting part  400  may further include at least one of a second HTL (upper HTL, HTL2)  520  disposed between the CGL  470  and the EML2  540 , a second ETL (upper ETL, ETL2)  550  disposed between the second electrode  220  and the EML2  540  and an EIL  560  disposed between the second electrode  220  and the ETL2  550 . Alternatively, the second emitting part  500  may further include a second EBL (upper EBL, EBL2) disposed between the HTL2  520  and the EML2  540 . 
     The HIL  410 , the HTL1  420 , the HTL2  520  and the EIL  560  may have substantially the same structure and components as described above. 
     The EML1  440  may include a first host and a first dopant, and the EML2  540  may include a second host and a second dopant. In one exemplary aspect, each of the first host and the second host may comprise independently the anthracene-based organic compound having the structure of Formulae 5 to 6 and each of the first dopant and the second dopant may comprise independently the boron-based organic compound having the structure of Formulae 7 to 8. The first host may be identical to or different from the second host and the first dopant may be identical to or different from the second dopant. The contents of the first dopant and the second dopant in each of the EML1  440  and the EML2  540  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     In one exemplary aspect, each of the ETL1  450  and the ETL2  550  may include independently, but is not limited to, at least one of oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, triazine-based compounds, and the like. 
     As an example, each of the ETL1  450  and the ETL2  550  may include independently, but is not limited to, tris-(8-hydroxyquinoline aluminum (Alq 3 ), Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), Liq, 2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD), spiro-PBD, 1,3,5-Tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), 4,7-diphenyl-1,10-phenanthroline (Bphen), 2,9-Bis(naphthalene-2-yl)4,7-diphenyl-1,10-phenanthroline (NBphen), 2,9-Dimethyl-4,7-diphenyl-1,10-phenaathroline (BCP), 3-(4-Biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 1,3,5-Tri(p-pyrid-3-yl-phenyl)benzene (TpPyPB), 2,4,6-Tris(3′-(pyridin-3-yl)biphenyl-3-yl)1,3,5-triazine (TmPPPyTz), Poly[9,9-bis(3′-(N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)] (PFNBr), tris(phenylquinoxaline) (TPQ), diphenyl-4-triphenysilyl-phenylphosphine oxide (TSPO1), 2-[4-(9,10-di-2-naphthalen-2-yl-2-anthracen-2-yl)phenyl]1-phenyl-1H-benzimidazole (ZADN) and combination thereof. 
     Alternatively, each of the ETL1  450  and the ETL2  550  may include a first electron transport material  452  and a second electron transport material  552 , respectively, each of which is independently the organic compound having the structure of Formulae 1 to 4. 
     In still another alternative aspect, each of the ETL1  450  and the ETL2  550  may further include independently the alkali metal and/or the alkaline earth metal doped to each of the first and second electron transport materials  452  and  552 . The contents of the alkali metal and/or the alkaline earth metal in each of the ETL1  450  and the ETL2  550  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The CGL  470  is disposed between the first emitting part  400  and the second emitting part  500 . The CGL  470  includes an N-type CGL (N-CGL)  480  disposed between the ETL1  450  and the HTL2  520  and a P-type CGL (P-CGL)  490  disposed between the N-CGL  480  and the HTL2  520 . The N-CGL  480  transports electrons to the EML1  440  of the first emitting part  400  and the P-CGL  490  transport holes to the EML2  540  of the second emitting part  500 . 
     The N-CGL  480  may be an organic layer including an N-type host, and optionally an N-type dopant. For example, the N-type host may include an N-type charge generation material  482  that may be the organic compound having the structure of Formulae 1 to 4. 
     As an example, the N-type dopant may include an alkali metal such as Li, Na, K and Cs and/or an alkaline earth metal such as Mg, Sr, Ba and Ra. The N-type dopant allows the N-CGL  480  to have excellent electron generation and electron injection. When the N-CGL  480  includes the alkali metal and/or the alkaline earth metal, the alkali metal and/or the alkaline earth metal as the N-type dopant binds to the N-type charge generation material  482 , which may be the organic compound having the structure of Formulae 1 to 4, in order to form a gap state. Accordingly, as energy level bandgap between the N-CGL  480  and the P-CGL  490  becomes small, electron injection property from the N-CGL  480  to the ETL1  450  may be improved. For example, the contents of the N-type dopant in the N-CGL  480  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The P-type CGL  490  may be an organic layer including a P-type host, and optionally a P-type dopant. For example, the P-type host may include the organic compound used in the HIL  420  and/or the HTL1 and HTL2  420  and  520 . 
     As an example, the P-type host may include, but is not limited to, NPB, TPD, N,N,N′,N′-tetraphenylenyl-benzidine (TNB), HAT-CN and combination thereof. The P-type dopant may include, but is not limited to, F4-TCNQ, 1,3,4,5,7,8-hexafluorotetracyanonaphthoquiodimethane (F6-TCNNQ), FeCl3, FeF3, SbCl5 and combination thereof. When the P-CGL  490  includes the P-type dopant, the contents of the P-type dopant in the P-CGL  490  may be, but is not limited to, about 1 wt % to about 40 wt %, for example, about 3 wt % to about 30 wt %. 
     In this aspect, each of the ETL1  450 , the ETL2  550  and the N-CGL  480  includes the first electron transport material  452 , the second electron transport material  552  and the N-type charge generation material  482 , respectively, at least one of which may be the organic compound having the structure of Formulae 1 to 4. Accordingly, the OLED D2 can lower its driving voltage and improve its luminous property. 
     In the above aspect, an OLED and an organic light emitting display device including one or two emitting part emitting blue light. In another exemplary aspect, an organic light emitting display device can implement full-color including white color. Now, we will explain the white OLED and an organic light emitting device including the white OLED.  FIG. 5  is a schematic cross-sectional view illustrating an organic light emitting display device in accordance with another exemplary aspect of the present disclosure. 
     As illustrated in  FIG. 5 , the organic light emitting display device  600  comprises a first substrate  602  that defines each of a red pixel region RP, a green pixel region GP and a blue pixel region BP, a second substrate  604  facing the first substrate  602 , a thin film transistor Tr over the first substrate  602 , an organic light emitting diode (OLED) D disposed between the first and second substrates  602  and  604  and emitting white (W) light and a color filter layer  680  disposed between the OLED D and the second substrate  604 . 
     Each of the first and second substrates  602  and  604  may include, but is not limited to, glass, flexible material and/or polymer plastics. For example, each of the first and second substrates  602  and  604  may be made of PI, PES, PEN, PET, PC and combination thereof. The first substrate  602 , over which a thin film transistor Tr and an organic light emitting diode D are arranged, forms an array substrate. 
     A buffer layer  606  may be disposed over the first substrate  602 , and the thin film transistor Tr is disposed over the buffer layer  606  correspondingly to each of the red pixel region RP, the green pixel region GP and the blue pixel region BP. The buffer layer  606  may be omitted. 
     A semiconductor layer  610  is disposed over the buffer layer  606 . As an example, the semiconductor layer  610  may be made of oxide semiconductor material or polycrystalline silicon. 
     A gate insulating layer  620  including an insulating material, for example, inorganic insulating material such as silicon oxide (SiO x ) or silicon nitride (SiN x ) is disposed on the semiconductor layer  610 . 
     A gate electrode  630  made of a conductive material such as a metal is disposed over the gate insulating layer  620  so as to correspond to a center of the semiconductor layer  610 . An interlayer insulting layer  640  including an insulating material, for example, inorganic insulating material such as silicon oxide (SiO x ) or silicon nitride (SiN x ), or an organic insulating material such as benzocyclobutene or photo-acryl, is disposed on the gate electrode  630 . 
     The interlayer insulating layer  640  has first and second semiconductor layer contact holes  642  and  644  that expose both sides of the semiconductor layer  610 . The first and second semiconductor layer contact holes  642  and  644  are disposed over opposite sides of the gate electrode  630  with spacing apart from the gate electrode  630 . 
     A source electrode  652  and a drain electrode  654 , which are made of a conductive material such as a metal, are disposed on the interlayer insulating layer  640 . The source electrode  652  and the drain electrode  654  are spaced apart from each other with respect to the gate electrode  630 , and contact both sides of the semiconductor layer  610  through the first and second semiconductor layer contact holes  642  and  644 , respectively. 
     The semiconductor layer  610 , the gate electrode  630 , the source electrode  652  and the drain electrode  654  constitute the thin film transistor Tr, which acts as a driving element. 
     Although not shown in  FIG. 5 , a gate line and a data line, which cross each other to define a pixel region, and a switching element, which is connected to the gate line and the data line, is may be further formed in the pixel region. The switching element is connected to the thin film transistor Tr, which is a driving element. In addition, a power line is spaced apart in parallel from the gate line or the data line, and the thin film transistor Tr may further include a storage capacitor configured to constantly keep a voltage of the gate electrode for one frame. 
     A passivation layer  660  is disposed on the source and drain electrodes  652  and  654  with covering the thin film transistor Tr over the whole first substrate  602 . The passivation layer  660  has a drain contact hole  662  that exposes the drain electrode  654  of the thin film transistor Tr. 
     The OLED D is located over the passivation layer  660 . The OLED D includes a first electrode  710  that is connected to the drain electrode  654  of the thin film transistor Tr, a second electrode  720  facing from the first electrode  710  and an emissive layer  730  disposed between the first and second electrodes  710  and  720 . 
     One of the first electrode  710  formed for each pixel region and the second electrode  720  disposed integrally over a whole display area may be an anode, and the other of the first electrode  710  and the second electrode  720  may be a cathode. In addition, one of the first and second electrodes  710  and  720  may be a transmissive (semi-transmissive) electrode, and the other of the first and second electrodes  710  and  720  may be a reflective electrode. 
     For example, the first electrode  710  may be an anode and may include a conductive material having relatively high work function value. For example, the first electrode  710  may include ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, and the like. 
     The second electrode  720  is disposed over the first substrate  602  above which the emissive layer  730  is disposed. The second electrode  720  may be a cathode and may include a conductive material with a relatively low work function value, for example, low resistance metal. As an example, the second electrode  720  may include, but is not limited to, Al, Mg, Ca, Ag, alloy thereof or combination thereof such as Al—Mg or Ag:Mg. 
     When the organic light emitting display device  600  is a bottom-emission type, the first electrode  710  may have a single layered structure of conductive oxide. Alternatively, when the organic light emitting display device  600  is a top-emission a reflective electrode or a reflective layer may be formed under the first electrode  710 . For example, the reflective electrode or the reflective layer may include, but is not limited to, Ag or APC alloy. In the OLED D of the top-emission type, the first electrode  710  may have a triple-layered structure of ITO/Ag/ITO or ITO/APC/ITO. The second electrode  720  is thin so as to have light-transmissive (semi-transmissive) property. 
     A bank layer  664  is disposed on the passivation layer  660  in order to cover edges of the first electrode  710 . The bank layer  664  exposes a center of the first electrode  710  corresponding to each of the red pixel RP, the green pixel GP and the blue pixel BP. The bank layer  664  may be omitted. 
     An emissive layer  730  is disposed on the first electrode  710 . As illustrated in  FIG. 6 , the emissive layer  730  may include multiple emitting parts  800 ,  900  and  1000 . Each emitting part may comprise respective EML. In addition, each emitting part may further include at least one of a HIL, a HTL, an EBL, an ETL and an EIL. 
     The color filter layer  680  is disposed over the OLED D and includes a red color filter  682 , a green color filter  684  and a blue color filter  686  each of which is disposed correspondingly to the red pixel region RP, the green pixel region GP and the blue pixel region BP, respectively. Although not shown in  FIG. 5 , the color filter layer  680  may be attached to the OLED D through an adhesive layer. Alternatively, the color filter layer  680  may be disposed directly on the OLED D. 
     In addition, an encapsulation film may be disposed over the second electrode  520  in order to prevent outer moisture from penetrating into the OLED D. The encapsulation film may have, but is not limited to, a laminated structure of a first inorganic insulating film, an organic insulating film and a second inorganic insulating film (see,  170  in  FIG. 2 ). 
     In addition, the organic light emitting display device  600  may further include a polarizing plate to reduce reflection of external light. For example, the polarizing plate may be a circular polarizing plate. When the organic light emitting display device  600  is a bottom-emission type, the polarizing plate may be disposed under the first substrate  602 . Alternatively, when the organic light emitting display device  600  is a top-emission type, the polarizing plate may be disposed over the encapsulation film, for example, over the second substrate  604 . 
     In  FIG. 5 , the light emitted from the OLED D is transmitted through the second electrode  720  and the color filter layer  680  is disposed over the OLED D. Alternatively, the light emitted from the OLED D is transmitted through the first electrode  710  and the color filter layer  680  may be disposed between the OLED D and the first substrate  602 . In addition, a color conversion layer may be formed between the OLED D and the color filter layer  680 . The color conversion layer may include a red color conversion layer, a green color conversion layer and a blue color conversion layer each of which is disposed correspondingly to each pixel region (RP, GP and BP), respectively, so as to covert the white (W) color light to each of a red, green and blue color lights, respectively. Alternatively, the organic light emitting display device  600  may comprise the color conversion film instead of the color filter layer  680 . 
     As described above, the white (W) color light emitted from the OLED D is transmitted through the red color filter  682 , the green color filter  684  and the blue color filter  686  each of which is disposed correspondingly to the red pixel region RP, the green pixel region GP and the blue pixel region BP, respectively, so that red, green and blue color lights are displayed in the red pixel region RP, the green pixel region GP and the blue pixel region BP. 
     Now, we will explain an OLED that can be applied into the organic light emitting display device  600  in detail.  FIG. 6  is a schematic cross-sectional view illustrating an OLED in accordance with another exemplary aspect of the present disclosure. As illustrated in  FIG. 6 , the OLED D3 includes first and second electrodes  710  and  720  facing each other and an emissive layer  730  disposed between the first and second electrodes  710  and  720 . 
     One of the first and second electrodes  710  and  720  is an anode and the other of the first and second electrodes  710  and  720  is a cathode. As an example, the first electrode  710  may be a cathode injecting holes and the second electrode  720  may be a cathode injecting electrons. In addition, one of the first and second electrodes  710  and  720  is a reflective electrode and the other of the first and second electrodes  710  and  720  is a transmissive (semi-transmissive) electrode. 
     The emissive layer  730  includes a first emitting part  800 , a second emitting part  900  and a third emitting part  1000 . The emissive layer  730  further includes a first charge generation layer (CGL1)  870  disposed between the first emitting part  800  and the second emitting part  900  and a second charge generation layer (CGL2)  970  disposed between the second emitting part  900  and the third emitting part  1000 . Accordingly, the first emitting part  800 , the CGL1  870 , the second emitting part  900 , the CGL2  970  and the third emitting part  1000  are sequentially formed over the first electrode  710 . In other words, the first emitting part  800  is disposed between the first electrode  710  and the CGL1  870 , the second emitting part  900  is disposed between the CGL1  870  and the CGL2  970  and the third emitting part  1000  is disposed between the second electrode  720  and the CGL2  970 . 
     The first emitting part  800  includes a first EML (lower EML, EML1)  840 . The first emitting part  800  may further includes at least one of an HIL  810  disposed between the first electrode  710  and the EML1  840 , a first HTL (lower HTL, HTL1)  820  disposed between the HIL  810  and the EML1  840  and a first ETL (lower ETL, ETL1)  850  disposed between the EML1  840  and the CGL1  870 . In addition, the first emitting part  800  may further include a first EBL (lower EBL, EBL1)  830  disposed between the HTL1  820  and the EML1  840 . 
     The second emitting part  900  includes a second EML (middle EML, EML2)  940 . The second emitting part  900  may further include at least one of a second HTL (middle HTL, HTL2)  920  disposed between the CGL1  870  and the EML2  940  and a second ETL (middle ETL, ETL2)  950  disposed between the EML2  940  and the CGL2  970 . 
     The third emitting part  1000  includes a third EML (upper EML, EML3)  1040 . The third emitting part  1000  may further include a third HTL (upper HTL, HTL3)  1020  disposed between the CGL2  970  and the EML3  1040 , a third ETL (upper ETL, ETL3)  1050  disposed between the second electrode  720  and the EML3  1040  and an EIL  1060  disposed between the second electrode  720  and the ETL3  1050 . In addition, the third emitting part  1000  may further include a second EBL (upper EBL, EBL2)  1030  disposed between the HTL3  1020  and the EML3  1040 . 
     The HIL  810 , the HTL1  820 , the HTL2  920 , the HTL3  1020  and the EIL  1060  may have substantially the same structure and components as described above. 
     In one exemplary aspect, each of the EML1  840  and the EML3  1040  may emit blue light, respectively. The EML1  840  may include a first host and a first dopant and the EML3  840  may include a second host and a second dopant. In one exemplary aspect, each of the first host and the second host may comprise independently the anthracene-based organic compound having the structure of Formulae 5 to 6 and each of the first dopant and the second dopant may comprise independently the boron-based organic compound having the structure of Formulae 7 to 8. The first host may be identical to or different from the second host and the first dopant may be identical to or different from the second dopant. The contents of the first dopant and the second dopant in each of the EML1  840  and the EML2  1040  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The EBL1  830  prevents electrons from transporting to the first electrode  710  through the EML1  840  and the EBL2  1030  prevent electrons from transporting to the CGL2  870  through the EML3  1040 . In one exemplary aspect, each of the EBL1  830  and the EBL2  1030  may be selected from independently, but is not limited to, the following spirofluorene-based organic compound having the structure of Formula 9: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In one exemplary aspect, each of the ETL1  850 , the ETL2  950  and the ETL3  1050  may include independently, but is not limited to, at least one of oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, triazine-based compounds, and the like. 
     As an example, each of the ETL1  850 , the ETL2  950  and the ETL3  1050  may include independently, but is not limited to, Alq 3 , BAlq, Liq, PBD, spiro-PBD, TPBi, Bphen, NBphen, BCP, TAZ, NTAZ, TpPyPB, TmPPPyTz, PFNBr, TPQ, TSPO1, (ZADN and combination thereof 
     Alternatively, each of the ETL1  850 , the ETL2  950  and the ETL3  1050  may include a first electron transport material  852 , a second electron transport material  952  and a third electron transport material  1052 , respectively, each of which is independently the organic compound having the structure of Formulae 1 to 4. 
     In still another alternative aspect, each of the ETL1  850 , the ETL2  950  and the ETL3  1050  may further include independently the alkali metal and/or the alkaline earth metal doped to each of the first to third electron transport materials  852 ,  952  and  1052 . The contents of the alkali metal and/or the alkaline earth metal in each of the ETL1  850  to the ETL3  1050  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The CGL1  870  is disposed between the first emitting part  800  and the second emitting part  900 . The CGL1  870  includes a first N-type CGL (N-CGL1)  880  disposed between the ETL1  850  and the HTL2  920  and a first P-type CGL (P-CGL1)  890  disposed between the N-CGL1  880  and the HTL2  920 . The N-CGL1  880  transports electrons to the EML1  840  of the first emitting part  800  and the P-CGL1  890  transport holes to the EML2  940  of the second emitting part  900 . 
     The CGL2  970  is disposed between the second emitting part  900  and the third emitting part  1000 . The CGL2  970  includes a second N-type CGL (N-CGL2)  980  disposed between the ETL2  950  and the HTL3  1020  and a second P-type CGL (P-CGL2)  990  disposed between the N-CGL1  980  and the HTL3  1020 . The N-CGL1  980  transports electrons to the EML2  940  of the second emitting part  900  and the P-CGL2  990  transport holes to the EML3  1040  of the third emitting part  1000 . 
     Each of the N-CGL1  880  and the N-CGL2  980  may be an organic layer including an N-type host, and optionally an N-type dopant, respectively. For example, each of the N-CGL1  880  and the N-CGL2  980  may include a first N-type charge generation material  882  and a second N-type charge generation material  982 , respectively, each of which may be independently the organic compound having the structure of Formulae 1 to 4, as the N-type host. The N-type dopant may include an alkali metal such as Li, Na, K and Cs and/or an alkaline earth metal such as Mg, Sr, Ba and Ra. In this case, the N-type dopant binds to the N-type host in order to form a gap state. Accordingly, as energy level bandgap between the N-CGL1  880  or the N-CGL2  980  and the P-CGL1  890  or the P-CGL2  990  becomes small, electron injection property from the N-CGL1  880  and the N-CGL2  980  to the ETL1  850  and the ETL2  950  may be improved. For example, the contents of the N-type dopant in each of the N-CGL1  880  and the N-CGL2  980  may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The P-type CGL  490  may be an organic layer including a P-type host, and optionally a P-type dopant. The kinds and contents of the P-type host and the P-type dopant may be substantially identical to the P-type host and the P-type dopant as described in the P-type dopant  490 . 
     The EML2  940  may include a lower middle EML (first layer)  940 A and an upper milled EML (second layer)  940 B. The lower middle EML  940 A is located adjacently to the HTL2  920  and the upper middle EML  940 B is located adjacently to the ETL2  950 . One of the lower middle EML  940 A and the upper middle EML  940 B may be a green EML and the other of the lower middle EML  940 A and the upper middle EML  940 B may be a red EML. In other words, a red EML and a green EML is sequentially laminated to form the EML2  940 . 
     For example, the lower middle EML  940 A may be the red EML. In this case, the lower middle EML  940 A may include red host (third host) and red dopant (third dopant). In one exemplary aspect, the third host may include a P-type red host (hole-type red host) and an N-type red host (electron-type red host). 
     As an example, the P-type red host may be selected from, but is not limited to, the following spirofluorene-based organic compounds having the structure of Formula 10, and the N-type red host may be selected from, but is not limited to, the following quinazoline-carbazole-based organic compounds having the structure of Formula 11: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In one exemplary aspect, the P-type red host and the N-type red host in the lower middle EML  940 A may be admixed with a weight ratio, but is not limited to, about 1:9 to about 9:1, for example, about 2:8 to about 8:2 or about 7:3 to about 3:7. 
     The red dopant (third dopant) may include at least one of red phosphorescent material, red fluorescent material and red delayed fluorescent material. In one exemplary aspect, the red phosphorescent material may be selected from, but is not limited to, the following phosphorescent materials having the structure of Formula 12: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The contents of the red dopant in the lower middle EML  940 A may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     The upper middle EML  940 B may be the green EML. In this case, the upper middle EML  940 B may include green host (fourth host) and green dopant (fourth dopant). In one exemplary aspect, the fourth host may include a P-type green host (hole-type green host) and an N-type green host (electron-type green host). 
     As an example, the P-type green host may be selected from, but is not limited to, the following biscarbazole-based organic compounds having the structure of Formula 13, and the N-type green host may be selected from, but is not limited to, the following triazine-based organic compounds having the structure of Formula 14: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In one exemplary aspect, the P-type green host and the N-type green host in the upper middle EML  940 B may be admixed with a weight ratio, but is not limited to, about 1:9 to about 9:1, for example, about 2:8 to about 8:2 or about 7:3 to about 3:7. 
     The green dopant (fourth dopant) may include at least one of green phosphorescent material, green fluorescent material and green delayed fluorescent material. In one exemplary aspect, the green phosphorescent material may be selected from, but is not limited to, the following phosphorescent materials having the structure of Formula 15: 
     
       
         
         
             
             
         
       
     
     The contents of the green dopant in the upper middle EML  940 B may be, but is not limited to, about 1 wt % to about 10 wt %, for example, about 1 wt % to about 5 wt %. 
     In this aspect, each of the ETL1  850 , the ETL2  950 , the ETL3  1050 , the N-CGL1  880  and the N-CGL2  980  includes the first electron transport material  852 , the second electron transport material  952 , the third electron transport material  1050 , the first N-type charge generation material  882 , and the second N-type charge generation material  982 , respectively, at least one of which may be the organic compound having the structure of Formulae 1 to 4. Accordingly, the OLED D3 can lower its driving voltage and improve its luminous property. 
     In  FIG. 6 , the OLED D3 has a tandem structure with three emitting parts. The OLED may further include additional emitting part and charge generation layer. Alternatively, one of the first and third emitting parts  800  and  1000  each of which includes the EML1  840  and the EML3  1040 , respectively, is omitted so that the OLED D3 has a double-stack structure. 
     In addition, an organic light emitting device in accordance with the present disclosure may include a color conversion layer.  FIG. 7  is a schematic cross-sectional view illustrating an organic light emitting display device in still another exemplary aspect of the present disclosure. 
     As illustrated in  FIG. 7 , the organic light emitting display device  1100  comprises a first substrate  1102  that defines each of a red pixel region RP, a green pixel region GP and a blue pixel region BP, a second substrate  1104  facing the first substrate  1102 , a thin film transistor Tr over the first substrate  1102 , an organic light emitting diode (OLED) D disposed between the first and second substrates  1102  and  1104  and emitting blue (B) light and a color conversion layer  1180  disposed between the OLED D and the second substrate  1104 . Although not shown in  FIG. 7 , a color filter layer may be disposed between the second substrate  1104  and the respective color conversion layer  1180 . 
     The thin film transistor Tr is disposed over the first substrate  1102  correspondingly to each of the red pixel region RP, the green pixel region GP and the blue pixel region BP. A passivation layer  1160 , which has a drain contact hole  1162  exposing one electrode, for example a drain electrode, constituting the thin film transistor Tr, is formed with covering the thin film transistor Tr over the whole first substrate  1102 . 
     The OLED D, which includes a first electrode  1210 , an emissive layer  1230  and the second electrode  1220 , is disposed over the passivation layer  1160 . The first electrode  1110  may be connected to the drain electrode of the thin film transistor Tr through the drain contact hole  1162 . In addition, a bank layer  1164  covering edges of the first electrode  1210  is formed at the boundary between the red pixel region RP, the green pixel region GP and the blue pixel region BP. In this case, the OLED D may have a structure of  FIG. 3  or  FIG. 4  and can emit blue (B) light. The OLED D is disposed in each of the red pixel region RP, the green pixel region GP and the blue pixel region BP to provide blue (B) light. 
     The color conversion layer  1180  may include a first color conversion layer  1182  corresponding to the red pixel region RP and a second color conversion layer  1184  corresponding to the green pixel region GP. As an example, the color conversion layer  1180  may include an inorganic luminescent material such as quantum dot (QD). 
     The blue (B) light emitted from the OLED D in the red pixel region RP is converted into red (R) color light by the first color conversion layer  1182  and the blue (B) light emitted from the OLED D in the green pixel region GP is converted into green (G) color light by the second color conversion layer  1184 . Accordingly, the organic light emitting display device  1100  can implement a color image. 
     In addition, when the light emitted from the OLED D is displayed through the first substrate  1102 , the color conversion layer  1180  may be disposed between the OLED D and the first substrate  1102 . 
     SYNTHESIS EXAMPLE 1: SYNTHESIS OF COMPOUND D1 
     (1) Synthesis of Intermediate A 
     
       
         
         
             
             
         
       
     
     1-bromo-4-acetylnaphthalene (14.5 g, 0.058 mmol), 8-aminoquinoline-7-carb aldehyde (10 g, 0.058 mmol), absolute ethanol (800 ml) and KOH (13 g, 0.232 mol) were put into a round bottom flask, and then the solution was refluxed for 15 hours. After the reactants were cooled to a room temperature (RT), the reactants were extracted with CH 2 Cl 2 /H 2 O (CH 2 Cl 2 , 150 ml) three times to recover an organic layer. The organic layer was concentrated under reduced pressure, and then recrystallized with ethyl acetate (EtOAc) to give the pure Intermediate A (10.5 g, yield: 47%). 
     (2) Synthesis of Intermediate B 
     
       
         
         
             
             
         
       
     
     The Intermediate A (10 g, 0.026 mol), bis(pinacolato)diborn (7.9 g, 0.04 mol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (pd(dppf)C12, 1.1 g, 0.2 mol), potassium acetate (KOAc, 9.2 g, 0.09 mol) and 1,4-dioxane (200 ml) were put into a round bottom flask, and then the solution was refluxed for 12 hours. After the reactants were cooled to a room temperature, the reactants were filtered with celite and then washed with CHCl 3  (150 ml) five times. The filtrate was concentrated under reduced pressure and recrystallized with EtOAc to give the pure Intermediate B (7.9 g, 0.023 mol, yield: 88%). 
     (3) Synthesis of Intermediate C 
     
       
         
         
             
             
         
       
     
     4,6-diboromobenzothiophene (10.0 g, 0.029 mol) dissolved in dry THF (250 ml) was put into a round bottom flask, and then n-BuLi (n-butyllithium, 1.6 M in hexane 20 ml, 0.032 mol) was added slowly into the solution at −78° C. under nitrogen atmosphere, and then the solution was stirred for 30 minutes. D 2 O (1.0 ml, 0.055 mol) was added into the reaction mixtures, then, the reaction mixture was raised to RT, and was stirred again for 1 hour. The reaction mixture was purified with silica column chromatography (eluent: CH 2 Cl 2 ) and then solvent was removed to give the pure Intermediate C (7.7 g, 0.029 mol, yield: &gt;99%). 
     (4) Synthesis of Compound D1 
     
       
         
         
             
             
         
       
     
     The Intermediate B (7.0 g, 0.02 mol), the Intermediate C (5.32 g, 0.02 mol), Tetrakis(triphenylphosphine)Palladium(0) (Pd(PPh 3 ) 4 , 0.9 g, 0.1 mmol), K 2 CO 3  (8.3 g, 0.06 mol) dissolved in a mixed solvent of toluene/EtOH (100 ml/40 ml) were put into a round bottom flask, and the solution was refluxed for 12 hours. After the reaction mixture was cooled to RT, and reaction solution was filtered to obtain a crude product. The crude product was dissolved in CH 2 Cl 2 , and the solution was died with MgSO 4  to remove the solvent. The crude product was purified with silica column chromatography (eluent: CHCl 3 ) to give pure Compound D1 (6.9 g, 0.014 mol, yield: 70%). 
     SYNTHESIS EXAMPLE 2: SYNTHESIS OF COMPOUND D2 
     
       
         
         
             
             
         
       
     
     The pure Compound D2 (6.7 g, 0.014 mol, yield: 70%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (7.0 g, 0.02 mol) and 4-bromodibenzothiophene-d7 (5.4 g, 0.02 mol) were used as the reactants. 
     SYNTHESIS EXAMPLE 3: SYNTHESIS OF COMPOUND D6 
     
       
         
         
             
             
         
       
     
     The pure Compound D6 (6.3 g, 0.013 mol, yield: 81%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (5.7 g, 0.016 mol) and 2-bromodibenzothiophene-d7 (4.5 g, 0.017 mol) were used as the reactants. 
     SYNTHESIS EXAMPLE 4: SYNTHESIS OF COMPOUND D7 
     (1) Synthesis of Intermediate D 
     
       
         
         
             
             
         
       
     
     2,8-dibromodibenzofuran (10.0 g, 0.031 mol) dissolved in dry THF (250 ml) was put into a round bottom flask, n-BuLi (1.6 M in hexane 20 ml, 0.032 mol) was added slowly into the solution at −78° C. under nitrogen atmosphere, and then the solution was stirred for 30 minutes. D 2 O (1.0 ml, 0.055 mol) was added into the reaction mixtures, then, the reaction mixture was raised to RT, and was stirred again for 1 hour. The reaction mixture was purified with silica column chromatography (eluent: CH 2 Cl 2 ) and then solvent was removed to give the pure Intermediate D (7.5 g, 0.30 mol, yield: 97%). 
     (2) Synthesis of Compound D7 
     
       
         
         
             
             
         
       
     
     The pure Compound D7 (6.7 g, 0.014 mol, yield: 70%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (7.0 g, 0.02 mol) and the Intermediate D (6.8 g, 0.02 mol) were used as the reactants. 
     SYNTHESIS EXAMPLE 5: SYNTHESIS OF COMPOUND D9 
     (1) Synthesis of Intermediate E 
     
       
         
         
             
             
         
       
     
     The Intermediate C (6.2 g, 0.023 mol) dissolved in acetic acid (250 ml) was put into a round bottom flask under nitrogen atmosphere, and then the solution was stirred. H 2 O 2  (30 wt % in H 2 O, 15.0 ml, 0.147 mol) was added into the solution, the solution was stirred at RT for 30 minutes and refluxed for 12 hours. The reaction mixture was cooled to RT, distilled water (300 ml) was added into the reaction mixture to obtain a solid, and then the solid was filtered under reduced pressure. Distilled water (300 ml) and H 2 O 2  (30 wt % in H 2 O, 15.0 ml) were added into the reaction mixture, the solution was stirred at RT for 1 hour and was filtered under reduced pressure to give the pure Intermediate E (6.0 g, 0.020 mol, yield: 87%). 
     (2) Synthesis of Compound D9 
     
       
         
         
             
             
         
       
     
      Compound D9 (3.8 g, 0.0073 mol, yield: 66%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (3.8 g, 0.011 mol) and the Intermediate E (3.5 g, 0.012 mol) were used as the reactants. 
     SYNTHESIS EXAMPLE 6: SYNTHESIS OF COMPOUND D11 
     (1) Synthesis of Intermediate F 
     
       
         
         
             
             
         
       
     
     The pure Intermediate F (6.9 g, 0.020 mol, yield: 87%) was obtained by repeating the synthetic process of the Intermediate E except that 2-bromo-6-deuterim-dibenzothiophene (6.2 g, 0.023 mol) was used as the reactant. 
     (2) Synthesis of Compound D11 
     
       
         
         
             
             
         
       
     
     Compound D11 (3.8 g, 0.0073 mol, yield: 66%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (3.8 g, 0.011 mol) and the Intermediate F (3.5 g, 0.012 mol) were used as the reactants. 
     SYNTHESIS EXAMPLE 7: SYNTHESIS OF COMPOUND D12 
     
       
         
         
             
             
         
       
     
      Compound D12 (7.4 g, 0.013 mol, yield: 70%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (3.8 g, 0.011 mol) and 2-bromodibenzothiophene dioxide-d7 (6.0 g, 0.020 mol) were used as the reactants. 
     Comparative Synthesis Example 1: Synthesis of Compound Ref. 2 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 2 (7.2 g, 0.015 mol, yield: 75%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (7.0 g, 0.02 mol) and 4-bromodibenzofuran (5.0 g, 0.02 mol) were used as the reactants. 
     Comparative Synthesis Example 2: Synthesis of Compound Ref. 3 
     (1) Synthesis of Intermediate G 
     
       
         
         
             
             
         
       
     
     The pure Intermediate G (9.3 g, 0.024 mol, yield: 89%) was obtained by repeating the synthetic process of the Compound D1 except that 1,4-dibromonaphthalene (8.0 g, 0.028 mol) and dibenzothiophen-4-yl boronic acid (6.1 g, 0.027 mol) were used as the reactants. 
     (2) Synthesis of Intermediate H 
     
       
         
         
             
             
         
       
     
     The pure Intermediate H (7.5 g, 0.021 mol, yield: 91%) was obtained by repeating the synthetic process of the Intermediate B except that the Intermediate G (9.0 g, 0.023 mol) was used as the reactant. 
     (3) Synthesis of Compound Ref 3 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 3 (4.8 g, 0.0097 mol, yield: 81%) was obtained by repeating the synthetic process of the Compound D1 except that 2-bromophenanthroline-d7 (3.3 g, 0.012 mol) and the Intermediate H (4.4 g, 0.012 mol) were used as the reactants. 
     Comparative Synthesis Example 3: Synthesis of Compound Ref. 4 
     (1) Synthesis of Intermediate I 
     
       
         
         
             
             
         
       
     
     The Intermediate I (10.4 g, 0.0266 mol, yield: 82%) was obtained by repeating the synthetic process of the Compound D1 except that phenanthroline-2-yl boronic acid (8.1 g, 0.036 mol) and 1,4-dibromo-naphthalene-d6 (9.5 g, 0.033 mol) were used as the reactants. 
     (2) Synthesis of Intermediate J 
     
       
         
         
             
             
         
       
     
     The pure Intermediate J (8.4 g, 0.0236 mol, yield: 89%) was obtained by repeating the synthetic process of the Intermediate B except that the Intermediate I (10.4 g, 0.0266 mol) was used as the reactant. 
     (3) Synthesis of Compound Ref 4 
     
       
         
         
             
             
         
       
     
      The pure Compound Ref. 4 (6.3 g, 0.013 mol, yield: 81%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate J (5.7 g, 0.016 mol) and 4-bromodibenzothiophene (4.5 g, 0.017 mol) were used as the reactants. 
     Comparative Synthesis Example 4: Synthesis of Compound Ref. 5 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 5 (7.2 g, 0.015 mol, yield: 75%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (7.0 g, 0.02 mol) and 4-bromo-5-phenyl-dibenzothiophene (6.8 g, 0.02 mol) were used as the reactants. 
     Comparative Synthesis Example 5: Synthesis of Compound Ref. 6 
     (1) Synthesis of Intermediate K 
     
       
         
         
             
             
         
       
     
     The Intermediate K (9.3 g, 0.025 mol, yield: 83%) was obtained by repeating the synthetic process of the Intermediate G, except that 1,4-dibromonaphthalene (9.6 g, 0.034 mol) and dibenzofuran-2-boronic acid (6.4 g, 0.030 mol) were used as the reactants. 
     (2) Synthesis of Intermediate L 
     
       
         
         
             
             
         
       
     
     The pure Intermediate L (7.1 g, 0.021 mol, yield: 84%) was obtained by repeating the synthetic process of the Intermediate B except that the Intermediate K (9.3 g, 0.025 mol) was used as the reactant. 
     (3) Synthesis of Compound Ref 6 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 6 (6.7 g, 0.0142 mol, yield: 71%) was obtained by repeating the synthetic process of the Compound D1 except that 2-bromophenanthroline (5.2 g, 0.02 mol) and the Intermediate L (6.8 g, 0.02 mol) were used as the reactants. 
     Comparative Synthesis Example 6: Synthesis of Compound Ref. 7 
     (1) Synthesis of Intermediate M 
     
       
         
         
             
             
         
       
     
     The pure Intermediate M (7.6 g, 0.029 mol, yield: 97%) was obtained by repeating the synthetic process of the Intermediate C except that 2,9-dibromophenanthroline (10.0 g, 0.030 mol) was used as the reactant. 
     (2) Synthesis of Compound Ref 7 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 7 (7.1 g, 0.015 mol, yield: 75%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate M (5.2 g, 0.02 mol) and the Intermediate L (6.8 g, 0.02 mol) were used as the reactants. 
     Comparative Synthesis Example 7: Synthesis of Compound Ref. 8 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 8 (6.3 g, 0.013 mol, yield: 81%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate J (5.7 g, 0.016 mol) and 2-bromodibenzofuran (4.5 g, 0.017 mol) were used as the reactants. 
     Comparative Synthesis Example 8: Synthesis of Compound Ref. 9 
     (1) Synthesis of Intermediate N 
     
       
         
         
             
             
         
       
     
     The pure Intermediate N (8.8 g, 0.026 mol, yield: 87%) was obtained by repeating the synthetic process of the Compound D1 except that 2,9-bromophenanthroline (10.0 g, 0.030 mol) and phenyl boronic acid (3.6 g, 0.030 mol) were used as the reactants. 
     (2) Synthesis of Compound Ref 9 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 9 (6.7 g, 0.0142 mol, yield: 71%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate N (5.2 g, 0.02 mol) and the Intermediate L (6.8 g, 0.02 mol) were used as the reactants. 
     Comparative Synthesis Example 9: Synthesis of Compound Ref. 10 
     (1) Synthesis of Intermediate O 
     
       
         
         
             
             
         
       
     
     4-bromodibenzothiophene (8.0 g, 0.030 mol) dissolved in acetic acid (250 ml) was put into a round bottom flask under nitrogen atmosphere, and then the solution was stirred. H 2 O 2  (30 wt % in H 2 O, 15.0 ml, 0.147 mol) was added into the solution, the solution was stirred at RT for 30 minutes and refluxed for 12 hours. The reaction mixture was cooled to RT, distilled water (300 ml) was added into the reaction mixture to obtain a solid, and then the solid was filtered under reduced pressure. Distilled water (300 ml) and H 2 O 2  (30 wt % in H 2 O, 15.0 ml) were added into the reaction mixture, the solution was stirred at RT for 1 hour and was filtered under reduced pressure to give the pure Intermediate O (8.1 g, 0.027 mol, yield: 97%). 
     (2) Synthesis of Compound Ref 10 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 10 (4.3 g, 0.0083 mol, yield: 69%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate B (4.5 g, 0.012 mol) and the Intermediate 0 (4.5 g, 0.015 mol) were used as the reactants. 
     Comparative Synthesis Example 10: Synthesis of Compound Ref. 11 
     (1) Synthesis of Intermediate P 
     
       
         
         
             
             
         
       
     
     The pure Intermediate P (8.6 g, 0.029 mol, yield: 97%) was obtained by repeating the synthetic process of the Intermediate O except that 2-bromodibenzothiophene (8.0 g, 0.030 mol) was used as the reactant. 
     (2) Synthesis of Intermediate Q 
     
       
         
         
             
             
         
       
     
     The pure Intermediate Q (7.4 g, 0.028 mol, yield: 93%) was obtained by repeating the synthetic process of the Intermediate B except that the Intermediate P (8.9 g, 0.030 mol) was used as the reactant. 
     (3) Synthesis of Intermediate R 
     
       
         
         
             
             
         
       
     
     The pure Intermediate R (10.3 g, 0.024 mol, yield: 89%) was obtained by repeating the synthetic process of the Intermediate G except that the 1,4-dibromonaphthalene (12.0 g, 0.042 mol) and the Intermediate Q (7.0 g, 0.027 mol) were used as the reactants. 
     (4) Synthesis of Compound Ref 11 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref. 11 (5.4 g, 0.010 mol, yield: 631%) was obtained by repeating the synthetic process of the Compound D1 except that 2-bromophenanthroline (4.1 g, 0.016 mol) and the Intermediate R (5.9 g, 0.014 mol) were used as the reactants. 
     Comparative Synthesis Example 11: Synthesis of Compound Ref. 12 
     
       
         
         
             
             
         
       
     
      The pure Compound Ref 12 (5.8 g, 0.011 mol, yield: 78%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate M (4.2 g, 0.016 mol) and the Intermediate R (5.9 g, 0.014 mol) were used as the reactants. 
     Comparative Synthesis Example 12: Synthesis of Compound Ref. 13 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 13 (6.8 g, 0.013 mol, yield: 65%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate J (7.0 g, 0.016 mol) and the Intermediate F (6.4 g, 0.022 mol) were used as the reactants. 
     Comparative Synthesis Example 13: Synthesis of Compound Ref. 14 
     (1) Synthesis of Intermediate S 
     
       
         
         
             
             
         
       
     
     The pure Intermediate S (6.5 g, 0.016 mol, yield: 80%) was obtained by repeating the synthetic process of the Intermediate G except that 1,10-phenanthroline-2-boronic acid-d7 (4.6 g, 0.020 mol) and 1,4-dibromonaphthalene-d6 (5.8 g, 0.020 mol) were used as the reactants. 
     (2) Synthesis of Compound Ref 14 
     
       
         
         
             
             
         
       
     
      The pure Compound Ref 14 (6.1 g, 0.012 mol, yield: 75%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate S (6.5 g, 0.016 mol) and dibenzothiophen-4-yl boronic acid-d7 (4.0 g, 0.017 mol) were used as the reactants. 
     Comparative Synthesis Example 14: Synthesis of Compound Ref. 15 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 15 (7.5 g, 0.014 mol, yield: 70%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate S (6.5 g, 0.016 mol) and dibenzofuran-2-yl boronic acid-d7 (4.0 g, 0.018 mol) were used as the reactants. 
     Comparative Synthesis Example 15: Synthesis of Compound Ref. 16 
     
       
         
         
             
             
         
       
     
     The pure Compound Ref 16 (7.5 g, 0.014 mol, yield: 70%) was obtained by repeating the synthetic process of the Compound D1 except that the Intermediate S (8.0 g, 0.020 mol) and 2-bromodibenzothiophene dioxide-d7 (7.0 g, 0.023 mol) were used as the reactants. 
     Example 1 (Ex. 1): Fabrication of OLED 
     An organic light emitting diode having a tandem structure where the Compound D1 was applied as the host into an N-CGL was fabricated. A glass substrate onto which ITO coated as a thin film was washed UV ozone, mounted onto evaporation system and transferred to a vacuum chamber for depositing emissive layer. Subsequently, an emissive layer and a cathode were deposited by evaporation from a heating boat under about 10 −7  Torr as the following order: 
     An HIL (HAT-CN, 50 Å); an HTL1 (NPB, 300 Å), an EML1 (Host 1 (97 wt %), Dopant 2 (3 wt %, 230 Å), an ETL1 (ZADN, 200 Å), an N-CGL (Compound D1 (98 wt %), Li (2 wt %), 120 Å), p-CGL (HAT-CN, 50 Å), an HTL2 (NPB, 450 Å), an EML2 (Host 1 (97 wt %), Dopant 2 (3 wt %), 230 Å), an ETL2 (ZADN, 300 Å), an EIL (LiF (50 wt %), Yb (50 wt %), 20 Å), a cathode (Ag:Mg=10:1 by weight, 130 Å). 
     After deposition of emissve layer and the cathode, the OLED was transferred from the depostion chamber to a dry box for film formation, followed by encapsulation using UV-curable epoxy and moisture getter. 
     Examples 2-7 (Ex. 2-7): Fabrication of OLED 
     An OLED was fabricated using the same procedure and the same material as in Example 1, except that Compound D2 (Ex. 2), Compound D6 (Ex. 3), Compound D7 (Ex. 4), Compound D9 (Ex. 5), Compound D11 (Ex. 6) and Compound D12 (Ex. 7), respectively, as the host in the N-CGL instead of Compound D1. 
     Comparative Example 1 (Ref 1): Fabrication of OLED 
     An OLED was fabricated using the same procedure and the same material as in Example 1, except the following Ref-1 as the host in the N-CGL instead of Compound D1. 
     
       
         
         
             
             
         
       
     
     Comparative Example 2-16 (Ref. 2-16): Fabrication of OLEDs 
     An OLED was fabricated using the same procedure and the same material as in Example 1, except Ref. 2 to Ref 16, respectively as the host in the N-CGL instead of Compound D1. 
     Experimental Example 1: Measurement of Luminous Properties of OLEDs 
     Each of the OLEDs, having 9 mm 2  of emission area, fabricated in Examples 1 to 7 and Comparative Examples 1 to 15 was connected to an external power source and then luminous properties for all the OLEDs were evaluated using a constant current source (KEITHLEY) and a photometer PR650 at room temperature. In particular, driving voltage (V), External quantum efficiency (EQE, relative value) and luminous lifespan (LT 95 , relative value) at which the luminance was reduced to 95% from initial luminance was measured at a luminance of 1000 cd/m 2 . The measurement results are indicated in the following Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Luminous Property of OLED 
               
            
           
           
               
               
               
               
               
            
               
                 Sample 
                 Compound 
                 Voltage(ΔV) 
                 EQE (%) 
                 LT 95  (%) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Ref. 1 
                 Ref. 1 
                 0.00 
                 100 
                 100 
               
               
                 Ref. 2 
                 Ref. 2 
                 −0.25 
                 107 
                 108 
               
               
                 Ref. 3 
                 Ref. 3 
                 −0.28 
                 103 
                 111 
               
               
                 Ref. 4 
                 Ref. 4 
                 −0.08 
                 99 
                 105 
               
               
                 Ref. 5 
                 Ref. 5 
                 0.05 
                 91 
                 97 
               
               
                 Ref. 6 
                 Ref. 6 
                 −0.25 
                 109 
                 102 
               
               
                 Ref. 7 
                 Ref. 7 
                 −0.26 
                 106 
                 107 
               
               
                 Ref. 8 
                 Ref. 8 
                 −0.11 
                 105 
                 103 
               
               
                 Ref. 9 
                 Ref. 9 
                 0.08 
                 82 
                 89 
               
               
                 Ref. 10 
                 Ref. 10 
                 0.05 
                 71 
                 72 
               
               
                 Ref. 11 
                 Ref. 11 
                 0.08 
                 74 
                 76 
               
               
                 Ref. 12 
                 Ref. 12 
                 0.12 
                 80 
                 82 
               
               
                 Ref. 13 
                 Ref. 13 
                 0.02 
                 84 
                 90 
               
               
                 Ref. 14 
                 Ref. 14 
                 −0.29 
                 118 
                 131 
               
               
                 Ref. 15 
                 Ref. 15 
                 −0.23 
                 115 
                 118 
               
               
                 Ref. 16 
                 Ref. 16 
                 −0.12 
                 106 
                 115 
               
               
                 Ex. 1 
                 D1 
                 −0.28 
                 115 
                 127 
               
               
                 Ex. 2 
                 D2 
                 −0.25 
                 108 
                 124 
               
               
                 Ex. 3 
                 D6 
                 −0.20 
                 113 
                 120 
               
               
                 Ex. 4 
                 D7 
                 −0.22 
                 118 
                 122 
               
               
                 Ex. 5 
                 D9 
                 −0.05 
                 105 
                 117 
               
               
                 Ex. 6 
                 D11 
                 0.01 
                 105 
                 113 
               
               
                 Ex. 7 
                 D12 
                 −0.08 
                 103 
                 115 
               
               
                   
               
            
           
         
       
     
     As indicated in Table 1, compared to the OLED fabricated in Ref. 1 where the N-CGL includes the Compound Ref 1 with an anthracene moiety, the OLEDs fabricated in Examples where the organic compound including the fused hetero aromatic moiety including oxygen or sulfur atom as a nuclear atom lowered their driving voltages and improved their luminous efficiency and luminous lifespan. 
     Compared to the OLEDs fabricated in Refs. 2, 6 and 10-11 where the N-CGL includes Compounds not deuterated in the whole molecule, the OLEDs fabricated in Examples where the N-CGL includes the organic compounds in which at least one nuclear carbon atom within the fused hetero aromatic moiety is deuterated showed equivalent driving voltages, but improved their luminous efficiency and luminous lifespan significantly. 
     In addition, compared to the OLEDs fabricated in Refs. 3-4, 7-8 and 12-13 where the N-CGL includes compounds in which the nuclear carbon atoms of the phenanthroline moiety or the center linker moiety, the OLEDs fabricated in Examples where the N-CGL includes the organic compounds in which at least one nuclear carbon atom within the fused hetero aromatic moiety is deuterated showed equivalent driving voltages, but improved their luminous efficiency and luminous lifespan significantly. 
     Moreover, compared to the OLEDs fabricated in Refs. 14-16 where the N-CGL includes compounds in which all the nuclear carbon atoms of the whole molecule, the OLEDs fabricated in Examples where the N-CGL includes the organic compound in which only at least one carbon atom with the fused hetero aromatic moiety is deuterated showed equivalent driving voltages and very similar luminous efficiency and luminous lifespan. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the invention. Thus, it is intended that the present disclosure cover the modifications and variations of the present disclosure provided they come within the scope of the appended claims.