English:
[0004] However, high purity is difficult to achieve for polymeric light emitting materials since such materials often contain certain amounts of structural defects in the polymer backbone, by-products produced during polymerization, and end groups remaining on the polymer chains. AU these impurities and/or defects in preparations of the polymers can affect efficiency and lifespan of electronic devices incorporating polymeric electroluminescent organic materials.
[0005] Small molecules represent another category of light emitting materials and have been widely used in organic light emitting devices, such as organic light emitting diodes (OLEDs), either as emitters or as charge transporting materials. It is possible to produce fairly pure small molecule light emitting materials due to use of purification processes such as sublimation or recrystallization process, which provides an advantage compared with light emitting polymers.
[0008] However, many of the current organic light emitting materials, both polymers and small molecules, typically have unbalanced charge transporting characteristics. Generally, light emitting materials are able to conduct only one charge carrier, either holes or electrons, but typically not both. For example, poly(l,4-phenylenevinylene)s or alkoxy-substituted poly(l,4-phenylenevinylene)s are good hole transporters, whereas tris-(8-hydroxyquinoline) aluminum (III) (Alq3) is an electron transporter, unbalanced charge transporting in OLED devices results in low device efficiency.
[0010] Although some such ambipolar materials have been developed, to date the reported device performance based on such materials is still not satisfactory.
[0011] Thus, there exists a need for new materials that can be used in an organic light emitting layer in an electroluminescent device.
[0013] Embodiments of compounds of formula (I) are electroluminescent, and as such are useful as organic layers in organic electroluminescent devices, and may be used to form the emissive layer, a charge injection layer, a charge transport layer or a hole blocking layer.
[0023] Figure 2 is a schematic diagram setting out a synthesis mechanisms for certain compounds of formula (I);
[0024] Figure 3 is a representation of a single layer device incorporating a thin film containing a compound of formula (I);
[0025] Figure 4 is a representation of a multi layer device incorporating at least one thin film containing a compound of formula (I);
[0026] Figure 5 is an I-V plot of devices with the configuration of ITO/PEDOTiPSS/PVKrdopant/TPBI/LiF/Ca/Ag, where the dopant is various compounds of formula (I);
[0027] Figure 6 is a V-L plot of devices with the configuration of ITO/PEDOTiPSS/PVKidopant/TPBI/LiF/Ca/Ag;
[0028] Figure 7 is an I-V plot of devices with the configuration of ITO/PEDOTiPSS/compounάVTPBI/LiF/Ca/Ag, where the compound is various compounds of formula (I);
[0029] Figure 8 is a V-L plot of devices with the configuration of ITO/PEDOTrPSS/compound/TPBI/LiF/Ca/Ag;
[0030] Figure 9 is a plot of external quantum efficiency vs luminance of devices with the configuration of ITO/PEDOTiPSS/compound/TPBI/LiF/Ca/Ag; and
[0031] Figure 10 is EL spectra of devices with a configuration of ITO/PEDOTiPSS/compound/TPBI/LiF/Ca/Ag.
[0032] Figure 11 is UVabsorbance spectra for various compounds of formula (I) dissolved in chloroform;
[0033] Figure 12 is a graph of the photoluminescence of various compounds of formula (I) measured in chloroform;
[0034] Figure 13 is a graph of the photoluminescence of various compounds of formula (I) measured in the solid state after spin coating chloroform solutions containing the compounds onto a quartz plate.
[0035] Embodiments of compounds of formula (I) described herein are electroluminescent, meaning that these compounds emit light when an electrical current is passed through them. Thus, these compounds are well suited to act as a charge transport layer or a light emitting layer in an organic electronic device.
[0036] Certain organic compounds are able to conduct charge due to inclusion of an extensive system of pi bonds in the molecules. That is, compounds with connected or conjugated pi systems, such as polyarylene compounds or polyarylenevinylene compounds (e.g. poly(phenylenevinylene)), have a set of pi molecular orbitals that overlap and extend the length of the molecule. These extended pi molecular orbitals, when unfilled or when only partially filled with electrons, provide channels across the molecule for transport of additional electrons across the molecule when the molecule is placed under a voltage bias. Several such extended pi orbitals can form across a conductive organic compound, each having different structure and energy levels. The molecular orbital having the lowest energy level is often an effective path for transport of extra electrons.
[0037] In order for these compounds to luminesce, as an electron is being transported across the molecule, one or more electrons must move from a filled or partially filled higher energy orbital to an unfilled or partially filled lower energy orbital. If the energy released by the electron as it passes from a high energy state to a low energy state is in the visible spectrum, these molecules are seen to emit light.
[0039] The described compounds are relatively small molecules when compared with organic polymers, and can readily be purified to a relatively high degree following preparation, for example by column chromatography or by crystallization from solution, resulting in a final compound of higher purity than a polymer, and which is relatively free of unreacted starting reagents and intermediates. Thus, inclusion of these compounds as a charge transporting or light emitting layer in organic electronic devices may result in a device that has a longer life span and that is more efficient in terms of charge transport.
[0040] The present compounds possess both electron transporting and hole transporting regions, and thus are ambipolar in terms of charge transport. As a result, these compounds have balanced charge transporting properties and thus are particularly suited for inclusion in an organic light emitting device, such as an OLED.
[0042] As well, the compounds of formula (I) have one or more electron withdrawing groups incorporated (labelled B and B' in Figure 1), to provide electron transporting properties to the compounds. At least one of Ar 6 and Ar 7 and optionally one or more of Ar 2 and Ar 3 is an electron withdrawing group or is substituted with electron withdrawing sύbstituent. Incorporation of one or more electron withdrawing group enhances electron injection and transporting in the light emissive layer, which may be able to improve the device efficiency of organic light emitting devices incorporating these compounds.
[0043] These compounds also have a central tertiary nitrogen, substituted with three Ar groups, Ar 1 , Ar 2 and Ar 3 (this portion is labelled C in Figure 1). Of the three Ar groups attached to the central nitrogen, at least Ar 1 is further connected to another nitrogen atom. Such a design assists in increasing the energy level of the highest occupied molecular orbital (HOMO) of the compound, thus facilitating the hole injection and hole transport properties of the compounds. As well, this design may result in decreased turn-on voltage and the operational voltage for electronic devices incorporating the compounds of formula (I).
[0044] The present compounds are thus described by formula (I), which is set out below.
[0049] It will be appreciated that where a particular Ar group is described as including an arylene or heterarylene group, but where such an arylene or heteroarylene occurs at an end of the molecule and is monovalent, that the particular group will be aryl or heteroaryl. For example, if Ar 6 is described as including an arylene or heteroarylene group and s is 2, then the terminal Ar 6 group in (Ar 6 ) S will include an aryl or heteroaryl group (provided it is not bonded or linked to another Ar group), but the penultimate Ar 6 group will include an arylene or heteroarylene group.
[0052] Thus, the symbol "Ar" as used herein refers generally to an aryl group, an arylene group, a heteroaryl group, a heteroarylene group, an aryl group and an adjacent vinylene group ("aryl vinylene"), an arylene group and an adjacent vinylene group ("arylene vinylene"), a heteroaryl group and an adjacent vinylene group ("heteroaryl vinylene"), a heteroarylene group and an adjacent vinylene group ("heteroarylene vinylene"), an aryl group and an adjacent ethynylene group ("aryl ethynylene"), an arylene group and an adjacent ethynylene group ("arylene ethynylene"), a heteroaryl group and an adjacent ethynylene group ("heteroaryl ethynylene"), or a heteroarylene group and an adjacent ethynylene group ("heteroarylene ethynylene").
[0055] In the above formula (I), each OfAr 1 , Ar 2 and Ar 3 is independently an arylene group; a heteroarylene group; an arylene vinylene group; a heteroarylene vinylene group; an arylene ethynylene group; or a heteroarylene ethynylene group; any of which may be further substituted with one or more of: branched or unbranched alkyl, branched or unbranched heteroalkyl, branched or unbranched alkenyl, branched or unbranched heteroalkenyl, branched or unbranched alkynyl, branched or unbranched heteroalkynyl, branched or unbranched alkoxy, aryl and heteroaryl group.
[0057] In particular embodiments, at least one of Ar 2 and Ar 3 comprises 9,9- dialkylfluorenylene. In particular embodiments, the 9,9-dialkylfluroenylene is 9,9-dihexylfluorenylene. In other particular embodiments, each OfAr 2 and Ar 3 comprises 9,9-dialkylfluorenylene. In yet other particular embodiments, each of Ar 2 and Ar 3 comprises 9,9-dihexylfluorenylene. In yet other particular embodiments, each OfAr 2 and Ar 3 is 9,9-dihexylfluorenylene.
[0058] In particular embodiments, Ar 1 is phenylene.
[0059] Each of Ar 4 and Ar 5 is independently an arylene group; a heteroarylene group; an arylene vinylene group; a heteroarylene vinylene group; an arylene ethynylene group; or a heteroarylene ethynylene group; any of which may be further substituted with one or more of: branched or unbranched alkyl, branched or unbranched heteroalkyl, branched or unbranched alkenyl, branched or unbranched heteroalkenyl, branched or unbranched alkynyl, branched or unbranched heteroalkynyl, branched or unbranched alkoxy, aryl and heteroaryl group. As mentioned above, for terminal Ar groups within Ar 4 or Ar 5 , the terminal Ar group will comprise an aryl or heteroaryl group as opposed to arylene or heteroarylene.
[0060] Furthermore, one or more OfAr 1 , Ar 4 and Ar 5 may be optionally independently substituted with one or more of: alkylthio, amino, hydroxyl, amido connected to the backbone through the nitrogen, carboxyl connected to the backbone through the oxygen, phenyl, naphthyl, thienyl, furyl, pyrrolyl and carbazolyl.
[0061] In particular embodiments, at least one of Ar 4 and Ar 5 is phenyl. In other particular embodiments, each of Ar 4 and Ar 5 is phenyl.
[0062] Furthermore, optionally one or more of the pairs of Ar 1 and Ar 2 ; Ar 1 and Ar 3 ; Ar 2 and Ar 3 ; Ar 4 and Ar 5 ; Ar 1 and Ar 4 ; and Ar 1 and Ar 5 may be connected between the two Ar groups in the pair via a single bond or via a linking group including O, S, Si, branched or unbranched, substituted or unsubstituted alkylene, branched or unbranched, substituted or unsubstituted alkenylene, branched or unbranched, substituted or unsubstituted alkynylene, as a connecting group. Thus, it will be appreciated that for example where Ar 4 or Ar 5 is connected to another Ar group, then the particular Ar 4 or Ar 5 will be a bivalent group rather than monovalent. For example, if Ar 4 is connected to Ar 1 by a linking group, then Ar 4 would be for example an arylene group rather than an aryl group. It will also be appreciated that where any of m, n, p, r, s, x or y is greater than 1, then the linking may occur between any two of the possible Ar groups. For example, if
[0063] In particular embodiments, Ar 4 and Ar 5 are connected to each other by a single bond. In particular embodiments, each OfAr 4 and Ar 5 is phenylene and Ar 4 and Ar 5 are connected to each other by a single bond.
[0064] Each of Ar 6 and Ar 7 is independently an arylene group; a heteroarylene group; an arylene vinylene group; a heteroarylene vinylene group; an arylene ethynylene group; or a heteroarylene ethynylene group; any of which may be substituted with one or more of: branched or unbranched alkyl, branched or unbranched heteroalkyl, branched or unbranched alkenyl, branched or unbranched heteroalkenyl, branched or unbranched alkynyl, branched or unbranched heteroalkynyl, branched or unbranched alkoxy, aryl and heteroaryl group. As mentioned above, for terminal Ar groups within Ar 6 or Ar 7 , the terminal Ar group will comprise an aryl or heteroaryl group as opposed to arylene or heteroarylene.
[0065] Additionally, at least one of Ar 6 and Ar 7 is an electron withdrawing Ar group and/or is substituted with one or more electron withdrawing substituents.
[0069] In certain embodiments, at least one OfAr 6 or Ar 7 is one or more of the following Ar groups, in which each of R, R', R" and R'" is independently halo, cyano, nitro, carbonyl, thionyl, sulphonyl, alkyl, perfluoroalkyl, alkoxy, aryl, arylene vinylene, or arylene ethynylene, and q is an integer from 0 to 6.
[0070] It will be appreciated that although certain of the Ar groups below are depicted as either monovalent or bivalent, any of groups may be either monovalent or bivalent, depending on the context in which the Ar group occurs in the compound, as described above. As well, certain of the compounds are depicted with the bond that attaches the group to the remaining portion of the compound as entering into the center of the Ar group ring, either at an atom or across a bond. It will be appreciated that such depiction is intended to represent that the particular Ar group may be attached to the remaining portion of the compound by a bond at any available position on the ring.
[0071] Each of m, n, p, r, s, x and y is independently an integer from 1 to 20. As such, it should be understood that each of m, n, p, r, s, x and y can be any number between 1 to 20 and any range within 1 to 20, such as for example, from 1 to 15, from 1 to 10 or from 1 to 5, or from 10 to 15 or from 10 to 20. If any one of m, n, p, r, s, x or y is greater than one, then the relevant Ar group (for example Ar 7 for r) is chosen independently for each occurrence of that Ar group. For example, where r is 5, each of the 5 Ar 7 groups is chosen independently from the remaining 4 Ar 7 groups.
[0072] In particular embodiments, at least one OfAr 6 and Ar 7 is phenyl, 4- trifluoromethylphenyl, 2-naphthyl, 3-benzothiophenyl, phenanthrenyl, 9,9- dihexylfluorenyl, pyrenyl, 9-phenylcarbazolyl, 4-cyanophenyl or 7-(4'- cyanophenyl)-9,9-dihexylfluorenyl. In particular embodiments, Ar 6 and Ar 7 are the same, and both are phenyl, 4-trifluoromethylphenyl, 2-naphthyl, 3- benzothiophenyl, phenanthrenyl, 9,9-dihexylfluorenyl, pyrenyl, 9- phenylcarbazolyl, 4-cyanophenyl or 7-(4'-cyanophenyl)-9,9-dihexylfluorenyl.
[0073] hi particular embodiments, Ar 1 is phenylyene, Ar 2 and Ar 3 are both 9,9-dihexylfluorenylene, Ar 4 and Ar 5 are both phenylene and are connected to each other by a single bond, Ar 6 and Ar 7 are the same and both are phenyl, 4- trifluoromethylphenyl, 2-naphthyl, 3-benzothiophenyl, phenanthrenyl, 9,9- dihexylfluorenyl, pyrenyl, 9-phenylcarbazolyl, 4-cyanophenyl or 7-(4'- cyanophenyl)-9,9-dihexylfluorenyl, and each of m, n, p, r, s, x and y is 1.
[0074] The compounds of formula (I) can be synthesized using standard organic synthesis techniques known in the art. Examples of suitable synthesis mechanisms are set out in Figure 2 and in the Examples as set out below. For example, the Ullmann reaction may be applied to couple an aromatic halide with an aromatic amine. As well, the Grignard reaction, the Stille reaction and the Suzuki coupling reaction may be used to link two aromatic functional groups.
[0075] As stated above, compounds of formula (I) can be purified by standard methods, such as column chromatography or by crystallization from solution. Such techniques are known and a skilled person will readily be able to apply such techniques to the compounds of formula (I), with minimal routine effort.
[0083] To form the thin film, the compound of formula (I) and any additional film components may be dissolved in a suitable organic solvent. Suitable solvents include chloroform, toluene, xylene, ethyl benzoate, 1,1,2,2-tetrachloroethane, THF, dichlorobenzene, mesitylene and mixtures of the aforesaid solvents.
[0085] The compounds of formula (I) and thin films containing such compounds may be used to construct electroluminescent devices, including single layer and multilayer devices. The compounds of formula (I) and thin films containing such compounds may form the emissive layer in an organic light emitting diode, the active layer in an organic thin film transistor or the active layer in an organic photovoltaic cell. Such devices and layers are known in the art.
[0089] The anode 330 is any material capable of conducting holes and injecting them into organic layers. Anode 330 may be gold, silver or indium tin oxide (ITO), or conductive polymer layers. The anode 320 may be reflective, transparent, semi-transparent or translucent.
[0091] In certain embodiments, one or more of the anode and the cathode may be deposited on a support 340, which may be transparent, semi-transparent or translucent. Support 340 may be rigid, for example quartz or glass, or may be a flexible polymeric substrate. Examples of flexible transparent semi-transparent or translucent substrates include, but are not limited to, polyimides, polytetrafluoroethylenes, polyethylene terephthalates, polyolefins such as polypropylene and polyethylene, polyamides, polyacrylonitrile and polyacrionitrile, polymethacrylonitrile, polystyrenes, polyvinyl chloride, and fluorinated polymers such as polytetrafluoroethylene.
[0092] The device may comprise further additional layers. In one embodiment, as depicted in Figure 4, the device 400 is an organic light emitting diode (OLED).
[0097] Each of the above layers may be for example, from about 01. run to about 200 nm thick or from about 10 run to about 100 nm thick.
[0099] Generally, the efficiency of OLED devices may be improved by incorporating a hole blocking layer. Without being limited to any particular theory, it is believed that the HOMO level of the hole blocking material prevents the charges from diffusing out of the emissive layer but the hole blocking material has a sufficiently low electron barrier to allow electrons to pass through the hole blocking layer and enter the emissive layer (see, for example, US 6,097,147; US 6,784,106 and US 20030230980).
[00104] As well, it will be appreciated that a material may serve more than one function in an electroluminescent device. Due to the ambipolar charge transporting nature of the compounds of formula (I), these compounds may be found in other layers in the described devices. For example, a compound of formula (I) may constitute, alone or as part of a mixture, the hole transporting layer, or the electron transporting layer.
[00108] Synthesis: The synthesis methods described below are depicted in the synthesis schematic depicted in Figure 2.
[00112] Synthesis of compound (B): Compound (B) was prepared following the above procedure. A mixture of 2-bromo-9,9-dihexyl-7-iodo-9H- fluorene (17.26 g, 32 mmol), copper (I) oxide (2.29 g, 16 mmol) and (A) (2.07 g, 8 mmol ) in 1-phenoxybenzene was heated to 210°C in an oil bath for 24 h under N 2 atmosphere. The reaction mixture was cooled to room temperature and then filtered to remove excess copper complex. The filtrate was evaporated to dryness and passed through a silica gel column to give product, yielding 4.35 g (50%). 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 8.190-8.171 (d, J = 7.7 Hz, 2H), 7.625-7.605 (d, J = 8.0 Hz, 2H), 7.531-7.440 (m, 12H), 7.351-7.263 (m, 6H), 7.175-7.157 (d, J = 7.6 Hz, 2H), 1.936-1.898 (m, 8H), 1.174-1.109 (m, 24H), 0.810-0.776 (t, J = 7.2
[00113] Synthesis of compound (C): Compound (C) was prepared through the following procedure. To a solution of (B) (2.16 g, 2 mmol) in anhydrous THF (40 mL) at -78 0 C was added n-butyllithium (5 mL, 8 mmol, 1.6M in hexane). The mixture was stirred at -78°C for 1 h. 2-isopropoxy-4,4,5,5-tetramethyl-l,3,2- dioxaborolane (2.4 mL, 12 mmol) was added rapidly to the solution. The mixture was allowed to warm to room temperature and stirred overnight. The mixture was then poured into water and extracted with diethyl ether. The organic extracts were combined and washed with brine and dried with anhydrous MgSO 4 . The solvent was removed under reduced pressure, and the crude product was purified by recrystallization from a hexane/chloroform mixture to afford product, yielding 1.36 g (58%). 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 8.186-8.166 (d, J= 8.0 Hz, 2H), 7.620-7.601 (d, J= 7.6 Hz, 2H), 7.505-7.435 (m, 12H), 7.334-7.257 (m, 6H), 7.168-7.149 (d, J= 7.6 Hz, 2H), 1.930-1.893 (m, 8H),1.589 (s, 24H), 1.168-1.104 (m, 24H), 0.804-0.770 (t, J= 7.2 Hz, 12H), 0.722 (m, 8H)
[00122] Synthesis of compound 9: A mixture of (B) (0.162 g, 0.15 mmol), 4-cyanophenylboronic acid (0.6 mmol), and tetrakis(triphenylphosphine) palladium (3.4mg, 0.003 mmol) were added to an air-free two-phase mixture of toluene (15 mL) and an aqueous 2M Na 2 CO 3 solution (12 mL). The resulting mixture was vigourously stirred under argon atmosphere at 110°C for.24 hours. The organic layer was separated and the aqueous phase was extracted with ether. The organic layers were washed with brine (2 x 50 mL), and dried with anhydrous MgSO 4 . The solvent was evaporated and the residue passed through a silica-gel column. 0.147 g of pure compound 9 were obtained by recrystallization in heptane with a yield of 87 0 Zc 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 8.172 (d, 2H), 7.758 (m, 10H), 7.683 (d, 2H), 7.592 (d, 2H), 7.534 (s, 2H), 7.460 (m, 6H), 7.366 (m, 2H), 7.301(m, 4H), 7.198 (m, 2H), 1.980 (m, 8H), 1.095 (m, 24H), 0.756(m, 20H). MS (MALDI): m/z = 1124.76 (calcd. for C 82 H 84 N 4 : 1124.67). Anal. Found: C, 87.34; H, 7.33, N, 5.06 (calcd.: C, 87.50; H, 7.52; N, 4.98).
[00128] The cathode was composed of 0.4 nm LiF, 20 nm Ca and 200 nm Ag, which were thermal deposited sequentially.
[00132] 60 mg of light emitting molecules, synthesized as described above, were dissolved in 4 ml of ethyl benzoate and filtered through a 0.2 mm PTFE filter for device fabrication.
[00137] Table 3 depicts the energy levels of compounds 1 to 10.
[00138] As can be understood by one skilled in the art, many modifications to the exemplary embodiments described herein are possible. The invention, rather, is intended to encompass all such modification within its scope, as defined by the claims.
[00140] Although various embodiments of the invention are disclosed herein, many adaptations and modifications may be made within the scope of the invention in accordance with the common general knowledge of those skilled in this art. Such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way. AU technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art of this invention, unless defined otherwise.

中文:
[0004]但是,因为聚合物发光材料经常含有在聚合物主链上的一定量的结构缺陷、在聚合反应过程中产生的副产物和残余在聚合物链上的端基,所以这些材料难以实现高纯度。在所述聚合物制备中的所有这些杂质和/或缺陷会影响包含聚合物电致发光有机材料的电子器件的效率和寿命。
[0005]小分子代表另一类发光材料并且已经或者作为发光体材料或者作为电荷传输材料而被广泛用在有机发光器件中,例如有机发光二极管(OLED)。由于使用了例如升华或者重结晶法的纯化方法,所以可以生产相当纯的小分子发光材料,这与发光聚合物相比是一个优点。
[0008]但是,许多目前的有机发光材料,包括聚合物和小分子,一般都具有不平衡的电荷传输特性。一般而言,发光材料只能够传导一种电荷载流子,或者空穴或者电子,但是一般不是两者兼具。例如,聚对苯乙炔或者烷氧基取代的聚对苯乙炔是良好的空穴传输体,而三-(8-羟基喹啉)铝(III)(Alq3)为一种电子传输体。在OLED器件中不平衡的电荷传输导致较低的器件效率。
[0010]虽然已经开发了一些这种双极性材料,但是迄今为止,所报道的基于这种材料的器件性能仍然不令人满意。
[0011]因此,需要开发新的材料,其能够用在电致发光器件中的有机发光层中。
[0013]通式(I)的化合物的实施方案是电致发光的,且因此可用作有机电致发光器件中的有机层,并且可以用于形成发光层、电荷注入层、电荷传输层或空穴阻挡层。
[0023]图2是说明通式(I)的某些化合物的合成机理的示意图;
[0024]图3是一个单层器件的示意图,其包括含有通式(I)的化合物的薄膜;
[0025]图4是一个多层器件的示意图,其包括至少一层含有通式(I)的化合物的薄膜;
[0026]图5是构型为ITO/PEDOT:PSS/PVK:掺杂剂/TPBI/LiF/Ca/Ag的器件的I-V曲线图,其中所述掺杂剂为通式(I)的各种化合物;
[0027]图6是构型为ITO/PEDOT:PSS/PVK:掺杂剂/TPBI/LiF/Ca/Ag的器件的V-L曲线图;
[0028]图7是构型为ITO/PEDOT:PSS/化合物/TPBI/LiF/Ca/Ag的器件的I-V曲线图,其中所述化合物为通式(I)的各种化合物;
[0029]图8是构型为ITO/PEDOT:PSS/化合物/TPBI/LiF/Ca/Ag的器件的V-L曲线图;
[0030]图9是构型为ITO/PEDOT:PS S/化合物/TPBI/LiF/Ca/Ag的器件的外部量子效率vs亮度的曲线图;
[0031]图10是构型为ITO/PEDOT:PS S/化合物/TPBI/LiF/Ca/Ag的器件的EL光谱;
[0032]图11是溶解在氯仿中的通式(I)的各种化合物的UV吸收光谱;
[0033]图12在氯仿中测量的通式(I)的各种化合物的光致发光的图;
[0034]图13是在将含有通式(I)的各种化合物的氯仿溶液旋涂在石英片上以后在固态测量的这些化合物的光致发光的图。
[0035]本发明描述的通式(I)的化合物的实施方案是电致发光的,意即当电流通过这些化合物时它们都发光。因此,这些化合物都非常适于作为有机电子器件中的电荷传输层或发光层。
[0036]由于在分子中包括大量的π键系统,所以某些有机化合物能够传导电荷。也即是说,具有连接或共轭π键系统的化合物,例如聚亚芳基化合物(polyarylene compound)或者聚亚芳基亚乙烯基化合物(polyarylenevinylene compound)(例如聚对苯乙炔),具有重叠并延伸分子长度的一系列π分子轨道。当这些延伸的π分子轨道未填充或者仅仅部分填充电子时,这些延伸的π分子轨道在将分子置于一偏压下时提供通过分子的通道以用于传输额外的电子通过分子。可以形成几个这种延伸的π轨道穿越导电有机化合物,每一个都具有不同的结构和能级。具有最低能级的分子轨道通常是用于传输额外电子的有效途径。
[0037]为了使这些化合物发光,当将电子输送通过分子时,一个或多个电子必须从填充或者部分填充的较高能量轨道移动到未填充或者部分填充的较低能量轨道。如果当电子从高能量态跃迁至低能量态时由该电子释放的能量位于可见光谱范围,就可以看到这些分子发光。
[0039]当与有机聚合物相比时,所述的化合物为相对较小的分子,并且可以在制备后例如通过柱色谱法或者通过从溶液中的结晶法容易地纯化至相对较高程度,使得最终的化合物的纯度高于聚合物,而且相对而言不含未反应的起始试剂和中间体。因此,在有机电子器件中包含这些化合物作为电荷传输层或者发光层可以得到具有更长寿命且电荷传输效率更高的器件。
[0040]本发明化合物同时拥有电子传输和空穴传输区域,因此在电荷传输方面是双极性的。因此,这些化合物具有平衡的电荷传输特性,并由此特别适合于用在例如OLED的有机发光器件中。
[0042]同样,通式(I)的化合物具有一个或者多个引入的吸电子基团(图1中标识为B和B′的部分),以向该化合物提供电子传输特性。Ar6和Ar7中的至少一个以及非必需地一个或者多个Ar2和Ar3为吸电子基团或者被吸电子取代基取代。一个或者多个吸电子基团的引入增强了发光层中的电子注入和传输,这可以提高含有这些化合物的有机发光器件的器件效率。
[0043]这些化合物还具有被三个Ar基团(Ar1、Ar2和Ar3)取代的中心叔氮原子(这个部分在图1中标识为C)。在连接至该中心氮原子的三个Ar基团中,至少Ar1是进一步连接至另一个氮原子上的。这种设计有助于增加该化合物的最高占据分子轨道(HOMO)的能级,由此有利于该化合物的空穴注入和空穴传输特性。同样,这种设计可以降低含有通式(I)的化合物的电子器件的启动电压和操作电压。
[0044]由此,用通式(I)描述本发明化合物,其在下面阐明。
[0049]应当理解的是,当将特定的Ar基团描述为包括亚芳基或者杂亚芳基,但是当该亚芳基或者杂亚芳基处于分子的末端且为单价时,则该特定基团应为芳基或者杂芳基。例如,如果将Ar6描述为包括亚芳基或者杂亚芳基且s为2,那么在(Ar6)s中的末端Ar6基团将包括芳基或者杂芳基(前提是其没有键合或者连接至另一个Ar基团),但是倒数第二个Ar6基团将包括亚芳基或者杂亚芳基。
[0052]这样,在本文中使用的符号“Ar”一般指的是芳基、亚芳基、杂芳基、杂亚芳基、芳基和毗邻的亚乙烯基(“芳基亚乙烯基”)、亚芳基和毗邻的亚乙烯基(“亚芳基亚乙烯基”)、杂芳基和毗邻的亚乙烯基(“杂芳基亚乙烯基”)、杂亚芳基和毗邻的亚乙烯基(“杂亚芳基亚乙烯基”)、芳基和毗邻的亚乙炔基(“芳基亚乙炔基”)、亚芳基和毗邻的亚乙炔基(“亚芳基亚乙炔基”)、杂芳基和毗邻的亚乙炔基(“杂芳基亚乙炔基”)或杂亚芳基和毗邻的亚乙炔基(“杂亚芳基亚乙炔基”)。
[0055]在上述通式(I)中,Ar1、Ar2和Ar3各自独立为亚芳基、杂亚芳基、亚芳基亚乙烯基、杂亚芳基亚乙烯基、亚芳基亚乙炔基或者杂亚芳基亚乙炔基,其中任何一个可以进一步被一个或者多个以下基团取代:支链或者无支链的烷基、支链或者无支链的杂烷基、支链或者无支链的链烯基、支链或者无支链的杂链烯基、支链或者无支链的炔基、支链或者无支链的杂炔基、支链或者无支链的烷氧基、芳基和杂芳基。
[0057]在特定的实施方案中,Ar2和Ar3中的至少一个包含9,9-二烷基亚芴基(9,9-dialkylfluorenylene)。在特定的实施方案中,所述9,9-二烷基亚芴基为9,9-二己基亚芴基。在另外的特定实施方案中,Ar2和Ar3各自包含9,9-二烷基亚芴基。在又一些特定的实施方案中,Ar2和Ar3各自包含9,9-二己基亚芴基。在再一些特定的实施方案中,Ar2和Ar3各自为9,9-二己基亚芴基。
[0058]在特定的实施方案中,Ar1为亚苯基。
[0059]Ar4和Ar5各自独立为亚芳基、杂亚芳基、亚芳基亚乙烯基、杂亚芳基亚乙烯基、亚芳基亚乙炔基或者杂亚芳基亚乙炔基,其中任何一个可以进一步被一个或者多个以下基团取代:支链或者无支链的烷基、支链或者无支链的杂烷基、支链或者无支链的链烯基、支链或者无支链的杂链烯基、支链或者无支链的炔基、支链或者无支链的杂炔基、支链或者无支链的烷氧基、芳基和杂芳基。如上所述,对于在Ar4或者Ar5中的末端Ar基团,该末端Ar基团将包括芳基或者杂芳基,而不是亚芳基或者杂亚芳基。
[0060]进而,Ar1、Ar4和Ar5中的一个或者多个可以非必需地由一个或者多个以下基团独立地取代:烷硫基、氨基、羟基、通过氮原子连接至主链上的酰氨基、通过氧原子连接至主链上的羧基、苯基、萘基、噻吩基、呋喃基、吡咯基和咔唑基。
[0061]在特定的实施方案中,Ar4和Ar5中的至少一个是苯基。在另外的特定实施方案中,Ar4和Ar5各自为苯基。
[0062]进而,非必需地,Ar1和Ar2、Ar1和Ar3、Ar2和Ar3、Ar4和Ar5、Ar1和Ar4以及Ar1和Ar5中的一对或者多对可以经由单键或者经由连接基团在两个Ar基团之间成对连接起来,所述连接基团包括O、S、Si、支链或者无支链的取代或者未取代的亚烷基、支链或者无支链的取代或者未取代的亚链烯基、支链或者无支链的取代或者未取代的亚炔基,作为连接基团。因此,应当理解的是,例如,当Ar4或者Ar5连接至另一个Ar基团时,则该特定Ar4或Ar5将会是二价基团而不是单价基团。例如,如果Ar4通过连接基团连接至Ar1,则Ar4将是例如亚芳基而不是芳基。还应理解的是,当m、n、p、r、s、x或y中的任何一个大于1时,则在任何两个可能的Ar基团之间都可以产生连接。例如,如果Ar1和Ar2连接,且如果p和n都为2,则Ar1基团中的任何一个都可以连接至Ar2基团中的任何一个。同样,Ar1基团中的多个基团可以连接至Ar2基团中的一个或者多个基团。
[0063]在特定的实施方案中,Ar4和Ar5通过单键彼此连接。在特定的实施方案中,Ar4和Ar5各自为亚苯基且Ar4和Ar5通过单键彼此连接。
[0064]Ar6和Ar7各自独立为亚芳基、杂亚芳基、亚芳基亚乙烯基、杂亚芳基亚乙烯基、亚芳基亚乙炔基或者杂亚芳基亚乙炔基,其中任何一个可以被一个或者多个以下基团取代:支链或者无支链的烷基、支链或者无支链的杂烷基、支链或者无支链的链烯基、支链或者无支链的杂链烯基、支链或者无支链的炔基、支链或者无支链的杂炔基、支链或者无支链的烷氧基、芳基和杂芳基。如上所述,对于在Ar6或者Ar7中的末端Ar基团,该末端Ar基团将包括芳基或者杂芳基,而不是亚芳基或者杂亚芳基。
[0065]另外,Ar6和Ar7中的至少一个为吸电子Ar基团和/或被一个或者多个吸电子取代基取代。
[0069]在某些实施方案中,Ar6或Ar7中的至少一个为一个或者多个下列Ar基团,其中R、R′、R′′和R′′′各自独立为卤素、氰基、硝基、羰基、亚硫酰基、磺酰基、烷基、全氟烷基、烷氧基、芳基、亚芳基亚乙烯基或者亚芳基亚乙炔基,且q为0~6的整数。
[0070]应当理解的是,虽然将某些下面的Ar基团描绘为单价或者二价,但是如上所述,根据该Ar基团在化合物中所处的位置,任何基团都可以或者是单价的或者是二价的。同样,将某些化合物描绘为带有以进入该Ar基团环的中心的形式的连接该基团和化合物的剩余部分的键,或者在原子上或者通过键。应当理解的是,这种描绘意图表示该特定Ar基团可以通过在该环上的任何一个可用位置的键连接至该化合物的剩余部分。
[0071]m、n、p、r、s、x和y各自独立为1~20的整数。同样的,应当理解的是,m、n、p、r、s、x和y各自可以是1~20之间的任一数值和在1~20内的任何范围,例如,1~15、1~10或1~5、或10~15或10~20。如果m、n、p、r、s、x或y中的任何一个大于1,则对于相关的Ar基团(例如,对于r的Ar7)的每次出现,该Ar基团的选择都是独立的。例如,当r为5时,则5个Ar7基团中的每一个的选择都独立于其余的4个Ar7基团。
[0072]在特定的实施方案中,Ar6和Ar7中的至少一个为苯基、4-三氟甲基苯基、2-萘基、3-苯并噻吩基、菲基、9,9-二己基芴基、芘基、9-苯基咔唑基、4-氰基苯基或者7-(4’-氰基苯基)-9,9-二己基芴基。在特定的实施方案中,Ar6和Ar7相同,并且均为为苯基、4-三氟甲基苯基、2-萘基、3-苯并噻吩基、菲基、9,9-二己基芴基、芘基、9-苯基咔唑基、4-氰基苯基或者7-(4’-氰基苯基)-9,9-二己基芴基。
[0073]在特定的实施方案中,Ar1为亚苯基,Ar2和Ar3均为9,9-二己基亚芴基,Ar4和Ar5均为亚苯基并且通过单键彼此相连,Ar6和Ar7相同且均为苯基、4-三氟甲基苯基、2-萘基、3-苯并噻吩基、菲基、9,9-二己基芴基、芘基、9-苯基咔唑基、4-氰基苯基或者7-(4’-氰基苯基)-9,9-二己基芴基,以及m、n、p、r、s、x和y各自为1。
[0074]通式(I)的化合物可以使用在本领域中已知的标准有机合成技术合成。适合的合成机理的实例阐明在图2中和在下面阐明的实施例中。例如可以使用乌尔曼反应(Ullmann reaction)来偶合芳香卤化物和芳胺。同样,可以使用格利雅反应(Grignard reaction)、斯蒂尔反应(Stille reaction)和铃木偶合反应(Suzuki coupling reaction)来连接两个芳香族官能团。
[0075]如上所述,通式(I)的化合物可以通过例如柱色谱法或者通过从溶液中结晶的标准方法进行纯化。这些技术是公知的,而且本领域中的技术人员通过最小的常规努力就能够容易地将这些技术应用于通式(I)的化合物。
[0083]为了形成所述薄膜,可以将通式(I)的化合物和任何其它的膜成分溶解在适合的有机溶剂中。适合的溶剂包括:氯仿、甲苯、二甲苯、苯甲酸乙酯、1,1,2,2-四氯乙烷、THF、二氯苯、1,3,5-三甲基苯和上述溶剂的混合物。
[0085]通式(I)的化合物和含有该化合物的薄膜可用于构建电致发光器件,包括单层和多层器件。通式(I)的化合物和含有该化合物的薄膜可以形成有机发光二极管中的发光层、有机薄膜晶体管的活性层或者有机光伏电池中的活性层。这些器件和层在本领域中是公知的。
[0089]阳极330是能够传输空穴并将其注入有机层中的任何材料。阳极330可以是金、银或氧化铟锡(ITO),或导电聚合物层。阳极330可以是反射的、透明的或半透明的(semi-transparent,translucent)。
[0091]在某些实施方案中,一个或者多个阳极和阴极可以沉积在支撑体340上,其可以是透明的或半透明的。支撑体340可以是刚性的,例如石英或玻璃,或者可以是柔性聚合物基板。柔性透明或半透明的基板的实例包括,但并不限于,聚酰亚胺、聚四氟乙烯、聚对苯二甲酸乙二醇酯、例如聚丙烯和聚乙烯的聚烯烃、聚酰胺、聚丙烯腈(polyacrylonitrile,polyacrionitrile)、聚甲基丙烯腈、聚苯乙烯、聚氯乙烯和例如聚四氟乙烯的氟化聚合物。
[0092]该器件可以进一步包括其它层。在一个实施方案中,如图4中所示,器件400为一个有机发光二极管(OLED)。
[0097]上述各层的厚度可以为,例如,约0.1nm~约200nm或者约10nm~约100nm。
[0099]通常,OLED器件的效率可以通过引入空穴阻挡层而增加。不受限于任何特殊理论,人们认为空穴阻挡材料的HOMO能级防止电荷从发光层扩散出去,但是空穴阻挡材料具有足够低的电子屏障,允许电子通过空穴阻挡层并进入发光层(例如参见US 6,097,147、US 6,784,106和US20030230980)。
[00104]同样,应当理解的是,一种材料可能在电致发光器件中提供一种以上的功能。由于通式(I)的化合物的双极性电荷传输性质,所以这些化合物可以用在上述器件的其它层中。例如,通式(I)的化合物可以单独或者作为混合物的一部分构成空穴传输层或者电子传输层。
[00108]合成:下面描述的合成方法描绘在图2中所示的合成示意图中。
[00112]化合物(B)的合成:按照上面的步骤制备化合物(B)。将在1-二苯醚中的2-溴-9,9-二己基-7-碘-9H-芴(17.26g,32mmol)、氧化亚铜(2.29g,16mmol)和(A)(2.07g,8mmol)的混合物在N2气氛下在油浴中加热至210°C反应24h。将反应混合物冷却至室温,然后过滤去除过量的铜络合物。滤液蒸发至干,并经硅胶柱得到4.35g产品,产率50%。1H NMR(400MHz,CDCl3):δ(ppm)8.190-8.171(d,J=7.7Hz,2H),7.625-7.605(d,J=8.0Hz,2H),7.531-7.440(m,12H),7.351-7.263(m,6H),7.175-7.157(d,J=7.6Hz,2H),1.936-1.898(m,8H),1.174-1.109(m,24H),0.810-0.776(t,J=7.2Hz,12H),0.726(m,8H)。
[00113]化合物(C)的合成:按照下面的步骤制备化合物(C)。向在-78°C的(B)(2.16g,2mmol)的无水THF(40mL)溶液中加入正丁基锂(5mL,8mmol,1.6M在己烷中)。混合物在-78°C搅拌1h。向该溶液中快速加入2-异丙氧基-4,4,5,5-四甲基-1,3,2-二氧杂环戊硼烷(2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane)(2.4mL,12mmol)。将混合物加热至室温并搅拌过夜。然后将该混合物倾倒入水中并用乙醚萃取。合并有机萃取液,用盐水洗涤并用无水MgSO4干燥。减压除去溶液,并通过从己烷/氯仿混合物中的重结晶纯化粗产物得到1.36g产物,产率58%。1H NMR(400MHz,CDCl3):δ(ppm)8.186-8.166(d,J=8.0Hz,2H),7.620-7.601(d,J=7.6Hz,2H),7.505-7.435(m,12H),7.334-7.257(m,6H),7.168-7.149(d,J=7.6Hz,2H),1.930-1.893(m,8H),1.589(s,24H),1.168-1.104(m,24H),0.804-0.770(t,J=7.2Hz,12H),0.722(m,8H)。
[00122]化合物9的合成:将(B)(0.162g,0.15mmol)、4-氰基苯基硼酸(0.6mmol)和四(三苯基膦)钯(3.4mg,0.003mmol)的混合物加入到无空气的甲苯(15mL)和2M Na2CO3水溶液(12mL)的两相混合物中。在氩气气氛下将所得到的混合物在110°C剧烈搅拌24小时。分离有机层并用醚萃取水溶液相。有机层用盐水洗涤(2×50mL),并用无水MgSO4干燥。蒸发溶剂并将残余物通过硅胶柱。通过在庚烷中重结晶得到0.147g纯化合物9,产率87%。1H NMR(400MHz,CDCl3):δ(ppm)8.172(d,2H),7.758(m,10H),7.683(d,2H),7.592(d,2H),7.534(s,2H),7.460(m,6H),7.366(m,2H),7.301(m,4H),7.198(m,2H),1.980(m,8H),1.095(m,24H),0.756(m,20H)。MS(MALDI):m/z=1124.76(对C82H84N4的计算值:1124.67)。分析发现:C,87.34;H,7.33;N,5.06(计算值:C,87.50;H,7.52;N,4.98)。
[00128]阴极由顺序热沉积的0.4nm LiF、20nm Ca和200nm Ag组成。
[00132]将60mg的如上所述合成的发光分子溶于4ml的苯甲酸乙酯中并通过0.2mm的PTFE过滤器过滤用于制备器件。
[00137]表3描述了化合物1~10的能级。
[00138]本领域中的技术人员可以理解的是,对在本文中描述的示例性实施方案进行的许多改进都是可能的。更确切地,本发明意图将所有这些改进涵盖在由权利要求书所限定的范围内。
[00140]虽然本文中公开了本发明的多种实施方案,但是根据本领域技术人员的公知常识在本发明的范围内可以作出许多修正和改进。这些改进包括为了以基本相同的方式达到相同的结果而对于本发明的任一方面的已知等价方案的替代方案。除非另有限定,在本文中使用的所有技术和科学术语具有与本发明领域内的技术人员通常理解的相同含义。