Organic light-emitting device

An organic light emitting device includes: a first electrode; a second electrode facing the first electrode; m emission units stacked between the first electrode and the second electrode; and m−1 charge generating layer(s) between the two adjacent emission units from among the m emission units, m−1 charge generating layer(s) including m−1 n-type charge generating layer(s) and m−1 p-type charge generating layer(s), wherein m is an integer of 2 or greater, a maximum emission wavelength of light emitted from at least one of the m emission units differs from that of light emitted from at least one of the other emission units, at least one of the m−1 n-type charge generating layer(s) includes a metal-containing material and an electron transporting metal-non-containing material.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2016-0029093, filed on Mar. 10, 2016, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND

One or more aspects of embodiments of the present disclosure relate to an organic light-emitting device.

2. Description of the Related Art

Organic light emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent brightness, driving voltage, and response speed characteristics, and can produce full-color images.

An organic light-emitting device may include a first electrode on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially positioned on the first electrode. Holes provided from, for example, the first electrode may move toward the emission layer through the hole transport region, and electrons provided from, for example, the second electrode may move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, may then recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light.

SUMMARY

One or more aspects of embodiments of the present disclosure are directed toward an organic light-emitting device having low driving voltage, high efficiency, and long lifespan.

According to one or more embodiments, an organic light-emitting device includes a first electrode;

a second electrode facing the first electrode;

m emission units stacked between the first electrode and the second electrode; and

m−1 charge generating layer(s) between each of the two adjacent emission units from among the m emission units, the m−1 charge generating layer(s) including m−1 n-type charge generating layer(s) and m−1 p-type charge generating layer(s),

wherein the m is an integer of 2 or greater,

a maximum emission wavelength of light emitted from at least one of the m emission units differs from that of light emitted from at least one of the other emission units,

at least one of the m−1 n-type charge generating layer(s) includes a metal-containing material and an electron transporting metal-non-containing material,

wherein the metal-containing material is selected from a metal, a metal complex, and combinations thereof,

the metal is selected from a rare-earth metal, a transition metal, a late transition metal, and combinations thereof, and

the metal complex is selected from an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, and combinations thereof.

DETAILED DESCRIPTION

According to an embodiment of the present disclosure, an organic light-emitting device may include a first electrode;

a second electrode facing the first electrode;

m emission units stacked between the first electrode and the second electrode; and

m−1 charge generating layer(s) between each of the two adjacent emission units from among the m emission units, the m−1 charge generating layer(s) including m−1 n-type charge generating layer(s) and m−1 p-type charge generating layer(s),

wherein m may be an integer of 2 or greater,

a maximum emission wavelength of light emitted from at least one of the m emission units may differ from that of light emitted from at least one of the other emission units,

at least one of the m−1 n-type charge generating layer(s) may include a metal-containing material and an electron transporting metal-non-containing material,

the metal-containing material may include a metal, a metal complex, or a combination thereof,

the metal may include a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, and

the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof.

FIG. 1illustrates a schematic view of an organic light-emitting device10according to an embodiment of the present disclosure. As shown inFIG. 1, an organic light-emitting device10according to an embodiment may include a first electrode110; a second electrode190facing the first electrode; m emission units153stacked between the first electrode110and the second electrode120; and m−1 charge generating layer(s)155between each of the two adjacent emission units153from among the m emission units153, the m−1 charge generating layer(s) including m−1 n-type charge generating layer(s)155′ and m−1 p-type charge generating layer(s)155″ (e.g., each charge generating layer155may include an n-type charge generating layer155′ and a p-type charge generating layer155″).

The “emission unit” as used herein is not particularly limited and may be any suitable emission unit capable of emission. In some embodiments, the emission unit may include at least one emission layer. In some embodiments, the emission unit may further include an organic layer, in addition to an emission layer.

The organic light-emitting device10may include m stacked emission units153, wherein m may be an integer of 2 or greater. m, which denotes the number of emission units, may be any suitable integer, and the upper limit of the number of emission units is not particularly limited. In some embodiments, the organic light-emitting device may include 2, 3, 4, or 5 emission units.

A maximum emission wavelength of light emitted from at least one of the m emission units may differ from that of light emitted from at least one of the other emission units. In some embodiments, in an organic light-emitting device that includes a first emission unit and a second emission unit that are stacked together, the maximum emission wavelength of light emitted from the first emission unit may differ from that of light emitted from the second emission unit. In this case, an emission layer of the first emission unit and that of the second emission unit may each independently include i) a single-layered structure including a single layer that includes a single material, ii) a single-layered structure including a single layer that includes a plurality of different materials, or iii) a multi-layered structure having a plurality of layers that include a plurality of different materials. Accordingly, light emitted from the first emission unit or the second emission unit may be single color light or mixed color light. In some embodiments, in an organic light-emitting device that includes a first emission unit, a second emission unit, and a third emission unit that are stacked together, the maximum emission wavelength of light emitted from the first emission unit may be the same as that of light emitted from the second emission unit, whereas the maximum emission wavelength of light emitted from the third emission unit may differ from that of light emitted from the first and second emission units. In some embodiments, the maximum emission wavelength of light emitted from the first emission unit, the maximum emission wavelength of light emitted from the second emission unit, and the maximum emission wavelength of light emitted from the third emission unit may differ from one another.

The organic light-emitting device10may include the charge generating layer155between the two adjacent emission units153from among the m emission units153. Here, the term “adjacent” as used herein may refer to an arrangement of two layers positioned closest to each other. In some embodiments, the term “two adjacent emission units” may refer to an arrangement of two emission units disposed closest to each other from among a plurality of emission units. For example, the term “adjacent” may refer to an arrangement of two layers that, in some embodiments, may physically contact each other, and in other embodiments, may have another layer disposed therebetween. In some embodiments, an emission unit adjacent to a second electrode may refer to an emission unit disposed closest to the second electrode from among a plurality of emission units. In some embodiments, the second electrode may physically contact the emission unit, or additional layers other than the emission units may be present between the second electrode and the emission unit. In some embodiments, an electron transport layer may be between the second electrode and the emission unit. A charge generating layer may be between two adjacent emission units.

The charge generating layer may function as a cathode for one of the two adjacent emission units by generating electrons and as an anode for the other emission unit by generating holes. The charge generating layer may separate adjacent emission units, while not being directed connected to an electrode. In some embodiments, an organic light-emitting device including m emission units may include m−1 charge generating layer(s).

The charge generating layer155may include the n-type charge generating layer155′ and the p-type charge generating layer155″. In some embodiments, the n-type charge generating layer155′ and the p-type charge generating layer155″ may directly contact each other so as to form an NP junction (e.g., a P-N junction). Due to the NP junction, electrons and holes may be concurrently or simultaneously generated between the n-type charge generating layer155′ and the p-type charge generating layer155″. The generated electrons may be transferred to one emission unit of the two adjacent emission units through the n-type charge generating layer155′. The generated holes may be transferred to another emission unit of the two adjacent emission units through the p-type charge generating layer155″. In addition, since the charge generating layers155may each include one n-type charge generating layer155′ and one p-type charge generating layer155″, the organic light-emitting device10that includes m−1 charge generating layer(s)155may include m−1 n-type charge generating layer(s)155′ and m−1 p-type charge generating layer(s)155″.

The term “n-type” as used herein may refer to n-type semiconductor properties, for example, properties capable of injection and transport of electrons. The term “p-type” as used herein may refer to p-type semiconductor properties, for example, properties capable of injection and transport of holes.

At least one of the m−1 n-type charge generating layer(s) may include a metal-containing material and an electron transporting metal-non-containing material (e.g., electron transporting material that does not include metal).

The metal-containing material may include a metal, a metal complex, or a combination thereof.

According to an embodiment, when at least one of the m−1 n-type charge generating layer(s) includes a metal as the metal-containing material, the metal may include a rare-earth metal, a transition metal, a late transition metal, or a combination thereof. In some embodiments, when at least one of the m−1 n-type charge generating layer(s) includes a metal as the metal-containing material, the metal may be selected from lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). According to an embodiment, when at least one of the m−1 n-type charge generating layer(s) includes a metal as the metal-containing material, the metal may be Yb, but embodiments are not limited thereto.

In one or more embodiments, when at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof. In some embodiments, when at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, a metal of the metal complex may be selected from lithium (Li), aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), zinc (Zn), and copper (Cu). According to an embodiment, when at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, the metal complex may be a Li complex or an Al complex, but embodiments are not limited thereto.

When at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, the metal complex may include at least one organic ligand selected from a hydroxyquinoline, a hydroxyisoquinoline, a hydroxy benzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyl oxazole, a hydroxyphenyl thiazole, a hydroxydiphenyl oxadiazole, a hydroxydiphenyl thiadiazole, a hydroxyphenyl pyridine, a hydroxyphenyl benzimidazole, a hydroxyphenyl benzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene. In some embodiments, when at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, the metal complex may include at least one selected from a substituted or unsubstituted hydroxyquinoline and a substituted or unsubstituted hydroxyphenyl benzothiazole, but embodiments are not limited thereto.

In some embodiments, when at least one of the m−1 n-type charge generating layer(s) includes a metal complex as the metal-containing material, the metal complex may be a lithium quinolate (Liq) and/or an aluminum quinolate (Alq3).

In some embodiments, a lowest unoccupied molecular orbital (LUMO) energy level of the electron transporting metal-non-containing material may be about −4.0 electron volts (eV) or greater. In some embodiments, a LUMO energy level of the electron transporting metal-non-containing material may be about −3.8 eV or greater. In some embodiments, a LUMO energy level of the electron transporting metal-non-containing material may be about −3.5 eV or greater.

Since an organic compound having a LUMO energy level of about −4.0 eV or greater has a slight difference in LUMO energy level with peripheral layers, the organic compound may efficiently (or suitably) transfer electrons generated in the n-type charge generating layer to the peripheral layers.

In one or more embodiments, the electron transporting metal-non-containing material may be an organic compound including at least one π electron-depleted nitrogen-containing ring.

The term “π electron-depleted nitrogen-containing ring” as used herein may refer to a C1-C60heterocyclic group having at least one *—N═*′ moiety as a ring-forming moiety.

In some embodiments, the electron transporting metal-non-containing material may be an organic compound including at least one selected from an imidazole ring, a pyrazole ring, a thiazole ring, an isothiazole ring, an oxazole ring, an isoxazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an indazole ring, a purine ring, a quinoline ring, an isoquinoline ring, a benzoquinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinazoline ring, a cinnoline ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a phenazine ring, a benzoimidazole ring, an iso-benzothiazole ring, a benzoxazole ring, an isobenzoxazole ring, a triazole ring, a tetrazole ring, an oxadiazole ring, a triazine ring, a thiadiazole ring, an imidazopyridine ring, an imidazopyrimidine ring, and indenoquinoline ring. In some embodiments, the electron transporting metal-non-containing material may be an organic compound including at least one selected from a phenanthroline ring, an imidazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring.

According to an embodiment, the electron transporting metal-non-containing material may be represented by Formula 1:
[Ar1]c1-[(L1)a1-R1]b1,  Formula 1

when c1 is 2 or greater, a plurality of Ar1(s) may be identical to or different from each other, and the plurality of Ar1(s) may be connected to a respective one another via a single bond,

a1 may be an integer selected from 0 to 5,

when a1 is 0, *-(L1)a1-*′ may be a single bond, and when a1 is 2 or greater, a plurality of L1(s) may be identical to or different from each other,

R1may be selected from a substituted or unsubstituted C3-C10cycloalkyl group, a substituted or unsubstituted C1-C10heterocycloalkyl group, a substituted or unsubstituted C3-C10cycloalkenyl group, a substituted or unsubstituted C1-C10heterocycloalkenyl group, a substituted or unsubstituted C6-C60aryl group, a substituted or unsubstituted C6-C60aryloxy group, a substituted or unsubstituted C6-C60arylthio group, a substituted or unsubstituted C1-C60heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q1)(Q2)(Q3), —C(═O)(Q1), —S(═O)2(Q1), and —P(═O)(Q1)(Q2),

wherein Q1to Q3may be each independently a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group,

b1 may be an integer selected from 1 to 5, and

when b1 is 2 or greater, a plurality of [(L1)a1-R1](s) may be identical to or different from each other.

In some embodiments, in Formula 1,

Ar1may be selected from the group consisting of:

L1may be selected from the group consisting of:

R1may be selected from the group consisting of:

wherein Q1, Q2, and Q31to Q33may be each independently a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group.

According to an embodiment, the electron transporting metal-non-containing material may be selected from Compounds 1 to 21, but embodiments are not limited thereto:

According to an embodiment, when an n-type charge generating layer, which includes the metal-containing material and the electron transporting metal-non-containing material, includes the metal as the metal-containing material, a weight ratio of the metal to the electron transporting metal-non-containing material may be in a range of about 0.01:100 to about 15:100. In some embodiments, a weight ratio of the metal to the electron transporting metal-non-containing material may be in a range of about 1:100 to about 5:100, but embodiments are not limited thereto.

According to an embodiment, when an n-type charge generating layer, which includes the metal-containing material and the electron transporting metal-non-containing material, includes the metal complex as the metal-containing material, a weight ratio of the metal complex to the electron transporting metal-non-containing material may be in a range of about 1:100 to about 100:1. In some embodiments, a weight ratio of the metal complex to the electron transporting metal-non-containing material may be in a range of about 1:50 to about 50:1. In some embodiments, a weight ratio of the metal complex to the electron transporting metal-non-containing material may be in a range of about 1:25 to about 25:1. In some embodiments, a weight ratio of the metal complex to the electron transporting metal-non-containing material may be in a range of about 3:7 to about 7:3, but embodiments are not limited thereto.

The p-type charge generating layer may substantially smoothly generate holes between the p-type charge generating layer and the n-type charge generating layer, and a material for the p-type charge generating layer is not particularly limited, and may be any suitable material capable of smoothly transferring generated holes to an adjacent emission unit. In some embodiments, the p-type charge generating layer may include only an organic compound. In some embodiments, the p-type charge generating layer may further include a metal oxide. In some embodiments, the p-type charge generating layer may further include a p-type dopant.

According to an embodiment, the p-type charge generating layer may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments are not limited thereto.

In some embodiments, a material for the p-type charge generating layer may include at least one selected from the group consisting of:

a metal oxide, such as tungsten oxide and/or molybdenum oxide;

compounds represented by Formula 221, but embodiments are not limited thereto:

According to an embodiment, the thickness of the n-type charge generating layer and that of the p-type charge generating layer may be each independently in a range of about 20 Å to about 1,000 Å. According to an embodiment, the thickness of the n-type charge generating layer and that of the p-type charge generating layer may be each independently in a range of about 50 Å to about 500 Å. According to an embodiment, the thickness of the n-type charge generating layer may be in a range of about 100 Å to about 300 Å, and the thickness of the p-type charge generating layer may be in a range of about 50 Å to about 200 Å, but embodiments are not limited thereto.

According to an embodiment, the organic light-emitting device10may further include a hole transport region between the first electrode and an emission unit adjacent to the first electrode from among the m emission units, wherein the hole transport region may include a p-dopant having a LUMO energy level of about −3.5 eV or less. The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments are not limited thereto. In some embodiments, the p-dopant may include at least one selected from the group consisting of:

a metal oxide, such as tungsten oxide and/or molybdenum oxide;

compounds represented by Formula 221, but is not limited thereto.

FIG. 2illustrates a schematic view of an organic light-emitting device11according to an embodiment. According to an embodiment, as shown inFIG. 2, the organic light-emitting device11may further include an electron transport layer157between the emission unit153adjacent to the second electrode190from among the m emission units153and the second electrode190.

The electron transport layer157may include a metal-containing material and an electron transporting metal-non-containing material (e.g., an electron transporting material that does not include metal).

The metal-containing material may include a metal, a metal complex, or a combination thereof.

In some embodiments, when the electron transport layer includes a metal as the metal-containing material, the metal may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof. In some embodiments, when the electron transport layer includes a metal as the metal-containing material, the metal may be selected from lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. According to an embodiment, when the electron transport layer includes a metal as the metal-containing material, the metal may be selected from Li, Mg, and Yb, but embodiments are not limited thereto.

In some embodiments, when the electron transport layer includes a metal complex as the metal-containing material, the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof. In some embodiments, when the electron transport layer includes a metal complex as the metal-containing material, the metal complex may include Li, Al, Ti, Zr, Hf, Zn, and/or Cu. According to an embodiment, when the electron transport layer includes a metal complex as the metal-containing material, the metal complex may be a Li complex or an Al complex, but embodiments are not limited thereto.

When the electron transport layer includes a metal complex as the metal-containing material, the metal complex may further include at least one organic ligand selected from a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyl oxazole, a hydroxyphenyl thiazole, a hydroxydiphenyl oxadiazole, a hydroxydiphenyl thiadiazole, a hydroxyphenyl pyridine, a hydroxyphenyl benzimidazole, a hydroxyphenyl benzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene. In some embodiments, when the electron transport layer includes a metal complex as the metal-containing material, the metal complex may include at least one selected from a substituted or unsubstituted hydroxyquinoline and a substituted or unsubstituted hydroxyphenylbenzothiazole.

In some embodiments, when the electron transport layer includes a metal complex as the metal-containing material, the metal complex may be a lithium quinolate (Liq) and/or an aluminum quinolate (Alq3).

The electron transporting metal-non-containing material included in the electron transport layer may be an organic compound including at least one π electron-depleted nitrogen-containing ring. In some embodiments, the electron transporting metal-non-containing material may be an organic compound including at least one selected from an imidazole ring, a pyrazole ring, a thiazole ring, an isothiazole ring, an oxazole ring, an isoxazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an indazole ring, a purine ring, a quinoline ring, an isoquinoline ring, a benzoquinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinazoline ring, a cinnoline ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a phenazine ring, a benzoimidazole ring, an iso-benzothiazole ring, a benzoxazole ring, an isobenzoxazole ring, a triazole ring, a tetrazole ring, an oxadiazole ring, a triazine ring, a thiadiazole ring, an imidazopyridine ring, an imidazopyrimidine ring, and indenoquinoline ring. In some embodiments, the electron transporting metal-non-containing material may be an organic compound including at least one selected from a phenanthroline ring, an imidazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring. In some embodiments, the electron transporting metal-non-containing material may be selected from Compounds 1 to 6 (as illustrated above).

In some embodiments, the metal-containing material and the electron transporting metal-non-containing material included in at least one of the m−1 n-type charge generating layer(s) may be the same as the metal-containing material and the electron transporting metal-non-containing material included in the electron transport layer, respectively. In some embodiments, at least one of the m−1 n-type charge generating layer(s) may include Yb as the metal-containing material and Compound 1 as the electron transporting metal-non-containing material. The electron transport layer may include Yb as the metal-containing material and Compound 1 as the electron transporting metal-non-containing material.

According to some embodiments, the metal-containing material included in at least one of the m−1 n-type charge generating layer(s) may differ from the metal-containing material included in the electron transport layer; the electron transporting metal-non-containing material included in at least one of the m−1 n-type charge generating layer(s) may differ from the electron transporting metal-non-containing material included in the electron transport layer; or the metal-containing material included in at least one of the m−1 n-type charge generating layer(s) may differ from the metal-containing material included in the electron transport layer, and the electron transporting metal-non-containing material included in at least one of the m−1 n-type charge generating layer(s) may differ from the electron transporting metal-non-containing material included in the electron transport layer.

In some embodiments, at least one of the m−1 n-type charge generating layer(s) may include Yb as the metal-containing material and Compound 1 as the electron transporting metal-non-containing material. The electron transport layer may include Li as the metal-containing material and Compound 1 as the electron transporting metal-non-containing material. In some embodiments, at least one of the m−1 n-type charge generating layer(s) may include Yb as the metal-containing material and Compound 1 as the electron transporting metal-non-containing material. The electron transport layer may include Liq as the metal-containing material and Compound 5 as the electron transporting metal-non-containing material.

According to some embodiments, m may be 3 or greater, and the m−1 n-type charge generating layers may all include the same metal-containing material and the same electron transporting metal-non-containing material, and

the metal-containing material included in the m−1 n-type charge generating layers may differ from the metal-containing material included in the electron transport layer; the electron transporting metal-non-containing material included in the m−1 n-type charge generating layers may differ from the electron transporting metal-non-containing material included in the electron transport layer; or the metal-containing material included in the m−1 n-type charge generating layers may differ from the metal-containing material included in the electron transport layer, and the electron transporting metal-non-containing material included in the m−1 n-type charge generating layers may differ from the electron transporting metal-non-containing material included in the electron transport layer.

According to an embodiment, the organic light-emitting device11may further include, in addition to an electron transport layer between the second electrode and an emission unit adjacent to the second electrode from among the m emission units, a hole transport region between the first electrode and an emission unit adjacent to the first electrode from among the m emission units, wherein the hole transport region may include a p-dopant having a LUMO energy level of about −3.5 eV or less. The p-dopant may be the same as described herein.

In an organic light-emitting device according to an embodiment, m may be 2. That is, in some embodiments, the organic light-emitting device may include only two emission units. In some embodiments, an organic light-emitting device may include a first electrode, a first emission unit, a first charge generating layer, a second emission unit, and a second electrode, which are stacked in this stated order. The organic light-emitting device may further include an electron transport layer between the second emission unit and the second electrode.

In an organic light-emitting device according to another embodiment, m may be 3. That is, in some embodiments, the organic light-emitting device may include only three emission units. In some embodiments, an organic light-emitting device may include a first electrode, a first emission unit, a first charge generating layer, a second emission unit, a second charge generating layer, a third emission unit, and a second electrode, which are stacked in this stated order. The organic light-emitting device may further include an electron transport layer between the third emission unit and the second electrode.

According to another embodiment, an organic light-emitting device may include a first electrode;

a second electrode facing the first electrode;

m emission units stacked between the first electrode and the second electrode; and

m−1 charge generating layer(s) between the two adjacent emission units from among the m emission units, m−1 charge generating layer(s) including m−1 n-type charge generating layer(s) and m−1 p-type charge generating layer(s),

wherein m may be an integer of 2 or greater,

a maximum emission wavelength of light emitted from at least one of the m emission units may differ from that of light emitted from at least one of the other emission units,

at least one of the m−1 n-type charge generating layer(s) may include a metal-containing material and an electron transporting metal-non-containing material,

the metal-containing material may include a metal, a metal complex, or a combination thereof,

the metal may include a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, and

the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof.

The organic light-emitting device may further include an electron transport layer between the second electrode and an emission unit adjacent to the second electrode from among the m emission units,

wherein the electron transport layer may include a metal-containing material and an electron transporting metal-non-containing material,

the metal-containing material may include a metal, a metal complex, or a combination thereof,

the metal may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, and

the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof.

According to another embodiment, an organic light-emitting device may include a first electrode;

a second electrode facing the first electrode;

m emission units stacked between the first electrode and the second electrode; and

m−1 charge generating layer(s) between two adjacent emission units from among the m emission units and including m−1 n-type charge generating layer(s) and m−1 p-type charge generating layer(s),

wherein m may be an integer of 2 or greater,

a maximum emission wavelength of light emitted from at least one of the m emission units may differ from that of light emitted from at least one of the other emission units,

at least one of the m−1 n-type charge generating layer(s) may include a metal-containing material and an electron transporting metal-non-containing material,

the metal-containing material may include a metal, a metal complex, or a combination thereof,

the metal may include a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, and

the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof.

The organic light-emitting device may further include an electron transport layer between the second electrode and an emission unit adjacent to the second electrode from among the m emission units,

wherein the electron transport layer may include a metal-containing material and an electron transporting metal-non-containing material,

the metal-containing material may include a metal, a metal complex, or a combination thereof,

the metal may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, and

the metal complex may include an alkali metal, an alkaline earth metal, a rare-earth metal, a transition metal, a late transition metal, or a combination thereof.

When the n-type charge generating layer includes a metal-containing material and an electron transporting metal-non-containing material, wherein the metal-containing material is a metal including a rare-earth metal, a transition metal, a late transition metal, or a combination thereof, the metal may have relatively great atomic weight or size compared to an alkali metal, and thus may exhibit no or reduced intermixing with peripheral layers. Accordingly, an organic light-emitting device including the n-type charge generating layer according to embodiments of the present disclosure may have long lifespan and/or improved stability.

In addition, when the n-type charge generating layer includes a metal-containing material and an electron transporting metal-non-containing material, wherein the metal-containing material is a metal complex, the metal in the metal complex may be stabilized by a ligand (e.g., an organic ligand included in the metal complex). Accordingly, an organic light-emitting device including the n-type charge generating layer according to embodiments of the present disclosure may have improved stability due to interaction between the metal complex and the electron transporting metal-non-containing material.

In addition, when the n-type charge generating layer includes a metal-containing material and an electron transporting metal-non-containing material, wherein the metal-containing material includes both a metal of a rare-earth metal, a transition metal, a late transition metal, or a combination thereof and a metal complex, an organic light-emitting device including the n-type charge generating layer may have both of the foregoing advantages.

FIG. 3is a schematic cross-sectional view illustrating an organic light-emitting device12according to an embodiment. The organic light-emitting device12may include the first electrode110, the organic layer150, and the second electrode190.

Hereinafter, the structure of the organic light-emitting device12according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection withFIG. 3.

First Electrode110

InFIG. 3, a substrate may be additionally disposed under the first electrode110or above the second electrode190. The substrate may be a glass substrate or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water-resistance.

The first electrode110may be formed by depositing or sputtering a material for the first electrode110on the substrate. When the first electrode110is an anode, a material for the first electrode110may be selected from materials with a high work function to facilitate hole injection.

The organic layer150may be positioned on the first electrode110. The organic layer150may include an emission unit.

The organic layer150may further include a hole transport region between the first electrode110and the emission unit and an electron transport region between the emission unit and the second electrode190.

Hole Transport Region in Organic Layer150

The hole transport region may include at least one layer selected from a hole injection layer, a hole transport layer, an emission auxiliary layer, and an electron blocking layer.

For example, the hole transport region may have a single-layered structure including a single layer including a plurality of different materials, or a multi-layered structure of hole injection layer/hole transport layer, hole injection layer/hole transport layer/emission auxiliary layer, hole injection layer/emission auxiliary layer, hole transport layer/emission auxiliary layer, or hole injection layer/hole transport layer/electron blocking layer, wherein for each structure, constituting layers are sequentially stacked from the first electrode110in this stated order, but the structure of the hole transport region is not limited thereto.

xa1 to xa4 may be each independently an integer selected from 0 to 3,

xa5 may be an integer selected from 1 to 10, and

In some embodiments, in Formula 202, R201and R202may optionally be bound to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R203and R204may optionally be bound to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In some embodiments, in Formulae 201 and 202,

L201to L205may be each independently selected from the group consisting of:

In one or more embodiments, xa1 to xa4 may be each independently 0, 1, or 2.

According to an embodiment, xa5 may be 1, 2, 3, or 4.

According to some embodiments, R201to R204and Q201may be each independently selected from the group consisting of:

wherein Q31to Q33may be the same as described herein.

According to some embodiments, at least one selected from R201to R203in Formula 201 may be selected from the group consisting of:

but embodiments are not limited thereto.

According to some embodiments, in Formula 202, i) R201and R202may be bound to each other via a single bond, and/or ii) R203and R204may be bound to each other via a single bond.

According to some embodiments, at least one selected from R201to R204in Formula 202 may be selected from the group consisting of:

a carbazolyl group; and

In some embodiments, the compound represented by Formula 201 may be represented by Formula 201A(1), but embodiments are not limited thereto:

In some embodiments, the compound represented by Formula 201 may be represented by Formula 201A-1, but embodiments are not limited thereto:

In some embodiments, the compound represented by Formula 202 may be represented by Formula 202A, but embodiments are not limited thereto:

In some embodiments, the compound represented by Formula 202 may be represented by Formula 202A-1:

descriptions of L201to L203, xa1 to xa3, xa5, and R202to R204may each independently be the same as descriptions thereof provided herein,

descriptions of R211and R212may each independently be the same as the description provided herein in connection with R203, and

For example, the hole transport region may include at least one compound selected from Compounds HT1 to HT39, but embodiments are not limited thereto:

The thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one selected from a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, and in some embodiments, about 100 Å to about 1,000 Å; the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, and in some embodiments, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer and the hole transport layer are within any of these ranges, satisfactory (or suitable) hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase the light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer, and the electron blocking layer may block or reduce the flow of electrons from an electron transport region. The emission auxiliary layer and the electron blocking layer may each independently include any of the materials as described above.

In one embodiment, the p-dopant may have a lowest unoccupied molecular orbital (LUMO) of −3.5 eV or less.

The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments are not limited thereto.

In some embodiments, the p-dopant may include at least one selected from the group consisting of:

a metal oxide, such as tungsten oxide and/or molybdenum oxide;

compounds represented by Formula 221, but embodiments are not limited thereto:

Emission Layer in Organic Layer150

In the organic light-emitting device12, an emission unit may include an emission layer, wherein the emission layer may have a stacked structure of two or more layers selected from a red emission layer, a green emission layer, a yellow emission layer, and a blue emission layer, in which the two or more layers may contact each other or may be separated from each other. In one or more embodiments, the emission layer may include two or more materials selected from a red-light emission material, a green-light emission material, a yellow-light emission material, and a blue-light emission material, in which the two or more materials may be mixed together in a single layer.

The emission unit may further include an upper auxiliary layer formed on the emission layer and/or a lower auxiliary layer formed below (e.g., under) the emission layer. The lower auxiliary layer may perform substantially the same functions as the above-described hole transport layer, emission auxiliary layer, and electron blocking layer; and the upper auxiliary layer may perform substantially the same functions as the below-described buffer layer, hole blocking layer, electron control layer, and electron transport layer. The materials for the lower auxiliary layer and the upper auxiliary layer may be the same as those described herein in connection with the materials for the hole transport region and the electron transport region.

The emission layer may include a host and a dopant. The dopant may include at least one selected from a phosphorescent dopant and a fluorescent dopant.

The amount of the dopant in the emission layer may be in a range of about 0.01 to about 15 parts by weight based on 100 parts by weight of the host, but is not limited thereto.

Host in Emission Layer

The host may include a compound represented by Formula 301:
[Ar301]xb11-[(L301)xb1-R301]xb21,  Formula 301

xb1 may be an integer selected from 0 to 5,

xb21 may be an integer selected from 1 to 5,

wherein Q301 toQ303may be each independently selected from a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but embodiments are not limited thereto.

In some embodiments, Ar301in Formula 301 may be selected from the group consisting of:

When xb11 in Formula 301 is 2 or greater, a plurality of Ar301(s) may be bound to a respective one another via a single bond.

In one or more embodiments, the compound represented by Formula 301 may be represented by Formula 301-1 or 301-2:

xb22 and xb23 may be each independently 0, 1, or 2,

descriptions of L301, xb1, R301, and Q31to Q33may each independently be the same as those provided herein,

descriptions of L302to L304may be each independently the same as the description provided herein in connection with L301,

descriptions of xb2 to xb4 may be each independently the same as the description provided herein in connection with xb1, and

descriptions of R302to R304may be each independently the same as the description provided herein in connection with R301.

In some embodiments, L301to L304in Formulae 301, 301-1, and 301-2 may be each independently selected from the group consisting of:

wherein Q31to Q33may be the same as those described herein.

In some embodiments, R301to R304in Formulae 301, 301-1, and 301-2 may be each independently selected from the group consisting of:

wherein Q31to Q33may be the same as those described herein.

In one or more embodiments, the host may include an alkaline earth metal complex. For example, the host may be selected from a beryllium (Be) complex (e.g., Compound H55 illustrated below), a magnesium (Mg) complex, and a zinc (Zn) complex.

Phosphorescent Dopant Included in an Emission Layer of the Organic Layer150

M may be selected from iridium (Ir), platinum (Pt), palladium (Pd), osmium

L401may be selected from ligands represented by Formula 402, and xc1 may be 1, 2, or 3; when xc1 is 2 or greater, a plurality of L401(s) may be identical to or different from each other,

L402may be an organic ligand, and xc2 may be an integer selected from 0 to 4; when xc2 is 2 or greater, a plurality of L402(s) may be identical to or different from each other,

X401to X404may be each independently nitrogen (N) or carbon (C),

X401and X403are bound to each other via a single bond or a double bond;

X402and X404are bound to each other via a single bond or a double bond,

A401and A402may be each independently a C5-C60carbocyclic group or a C1-C60heterocyclic group,

X406may be a single bond, O, or S,

xc11 and xc12 may be each independently an integer selected from 0 to 10, and

* and *′ in Formula 402 may each independently indicate a binding site to M in Formula 401.

In one or more embodiments, in Formula 402, i) X401may be nitrogen, and X402may be carbon, or ii) X401and X402may both be nitrogen.

According to some embodiments, R401and R402in Formula 402 may be each independently selected from the group consisting of:

a C1-C20alkyl group and a C1-C20alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a phenyl group, a naphthyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornanyl group, and a norbornenyl group;

wherein Q401to Q403may be each independently selected from a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, and a naphthyl group, but embodiments are not limited thereto.

In one or more embodiments, when xc1 in Formula 401 is 2 or greater, two A401(s) in a plurality of L401(s) may optionally be bound to each other via X407as a linking group, and two A402(s) may optionally be bound to each other via X408as a linking group (see e.g., Compounds PD1 to PD4 and PD7). X407and X408may be each independently selected from a single bond, *—O—*′, *—C(═O)—*′, *—N(Q413)-*′, *—C(Q413)(Q414)-*′ or *—C(Q413)=C(Q414)-*′ wherein, Q413and Q414may be each independently selected from hydrogen, deuterium, a C1-C20alkyl group, a C1-C20alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but embodiments are not limited thereto.

In some embodiments, the phosphorescent dopant may include, for example, at least one selected from Compounds PD1 to PD25, but embodiments are not limited thereto:

Fluorescent Dopant in Emission Layer

The fluorescent dopant may include an arylamine compound or a styrylamine compound.

In some embodiments, the fluorescent dopant may include a compound represented by Formula 501:

xd1 to xd3 may be each independently an integer selected from 0 to 3,

xd4 may be an integer selected from 1 to 6.

In some embodiments, Ar5o1in Formula 501 may be selected from the group consisting of:

In one or more embodiments, L501to L503in Formula 501 may be each independently selected from the group consisting of:

According to some embodiments, R501and R501in Formula 502 may be each independently selected from the group consisting of:

In one or more embodiments, xd4 in Formula 501 may be 2, but embodiments are not limited thereto.

In some embodiments, the fluorescent dopant may be selected from Compounds FD1 to FD22:

In some embodiments, the fluorescent dopant may be selected from the compounds below, but embodiments are not limited thereto:

Electron Transport Region in Organic Layer150

The electron transport region may include at least one selected from a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, and an electron injection layer, but is not limited thereto.

In some embodiments, the electron transport region may have a structure of electron transport layer/electron injection layer, a structure of hole blocking layer/electron transport layer/electron injection layer, a structure of electron control layer/electron transport layer/electron injection layer, or a structure of buffer layer/electron transport layer/electron injection layer, wherein the layers of these structures are sequentially stacked in these stated orders on an emission layer. However, the structure of the electron transport region is not limited thereto.

The electron transport region (e.g., a buffer layer, a hole blocking layer, an electron control layer, and/or an electron transport layer in the electron transport region) may include a metal-free compound containing at least one π electron-depleted nitrogen-containing ring.

The term “π electron-depleted nitrogen-containing ring” as used herein may refer to a C1-C60heterocyclic group having at least one *—N═*′ moiety as a ring-forming moiety.

Non-limiting examples of the π electron-depleted nitrogen-containing ring may include an imidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, an indazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, a phthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline, a phenanthridine, an acridine, a phenanthroline, a phenazine, a benzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, thiadiazole, an imidazopyridine, an imidazopyrimidine, and an azacarbazole, but are not limited thereto.

In some embodiments, the electron transport region may include a compound represented by Formula 601:
[Ar601]xe11-[(L601)xe1-R601]xe21,  Formula 601

xe1 may be an integer selected from 0 to 5,

wherein Q601to Q603may be each independently a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and

xe21 may be an integer selected from 1 to 5.

In some embodiments, at least one selected from the xe11 number of Ar601(s) and the xe21 number of R601(s) may include a π electron-depleted nitrogen-containing ring.

In some embodiments, ring Ar601in Formula 601 may be selected from the group consisting of:

When xe11 in Formula 601 is 2 or greater, a plurality of Ar601(s) may be bound to each other via a single bond.

In one embodiment, Ar601in Formula 601 may be an anthracene group.

In some embodiments, the compound represented by Formula 601 may be represented by Formula 601-1:

X614may be N or C(R614), X615may be N or C(R615), X616may be N or C(R616), and at least one selected from X614to X616may be N,

descriptions of L611to L613may be each independently the same as the description provided herein in connection with L601,

descriptions of xe611 to xe613 may be each independently the same as the description provided herein in connection with xe1,

descriptions of R611to R613may be each independently substantially the same as the description provided herein in connection with R601, and

In one embodiment, L601and L611to L613in Formulae 601 and 601-1 may be each independently selected from the group consisting of:

In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may be each independently selected from 0, 1, and 2.

In some embodiments, R601and R611to R613in Formulae 601 and 601-1 may be each independently selected from the group consisting of:

wherein Q601and Q602may be each independently the same as described herein.

The electron transport region may include at least one compound selected from Compounds ET1 to ET36, but embodiments are not limited thereto:

The thickness of the buffer layer, the hole blocking layer, and the electron control layer may be each independently in a range of about 20 Å to about 1,000 Å. When the thicknesses of the buffer layer, the hole blocking layer, and the electron control layer are each within any of these ranges, the electron transport region may have excellent (or suitable) hole blocking characteristics or electron control characteristics without a substantial increase in driving voltage.

The thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, and in some embodiments, about 150 Å to about 500 Å. When the thickness of the electron transport layer is within any of these ranges, the electron transport layer may have satisfactory (or suitable) electron transport characteristics without a substantial increase in driving voltage.

The electron transport region (e.g., the electron transport layer in the electron transport region) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include at least one selected from an alkali metal complex and an alkaline earth metal complex. The alkali metal complex may include a metal ion selected from an Li ion, a Na ion, a K ion, a Rb ion, and a Cs ion, and the alkaline earth metal complex may include a metal ion selected from a Be ion, a Mg ion, a Ca ion, an Sr ion, and a Ba ion. Ligands respectively coordinated with the metal ion of the alkali metal complex or the alkaline earth metal complex may be each independently selected from a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyl oxazole, a hydroxyphenyl thiazole, a hydroxydiphenyl oxadiazole, a hydroxydiphenyl thiadiazole, a hydroxyphenyl pyridine, a hydroxyphenyl benzimidazole, a hydroxyphenyl benzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but embodiments are not limited thereto.

In some embodiments, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) and/or Compound ET-D2:

The electron transport region may include an electron injection layer that facilitates injection of electrons from the second electrode190. The electron injection layer may directly contact the second electrode190.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare-earth metal, an alkali metal compound, an alkaline earth metal compound, a rare-earth metal compound, an alkali metal complex, an alkaline earth metal complex, a rare-earth metal complex, or a combination thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In one embodiment, the alkali metal may be selected from Li, Na, and Cs. In one or more embodiments, the alkali metal may be Li or Cs, but is not limited thereto.

The alkali metal compound, the alkaline earth metal compound, and the rare-earth metal compound may be each independently selected from oxides and halides (e.g., fluorides, chlorides, bromides, and/or iodines) of the alkali metal, the alkaline earth metal, and the rare-earth metal, respectively.

In some embodiments, the alkali metal compound may be selected from alkali metal oxides (such as Li2O, Cs2O, and/or K2O) and alkali metal halides (such as LiF, NaF, CsF, KF, LiI, NaI, CsI, and/or KI). In one embodiment, the alkali metal compound may be selected from LiF, Li2O, NaF, LiI, NaI, CsI, and KI, but is not limited thereto.

The alkaline earth metal compound may be selected from alkaline earth metal compounds, such as BaO, SrO, CaO, BaxSr1-xO (wherein 0<x<1), and/or BaxCa1-xO (wherein 0<x<1). In one embodiment, the alkaline earth metal compound may be selected from BaO, SrO, and CaO, but is not limited thereto.

The rare-earth metal compound may be selected from YbF3, ScF3, ScO3, Y2O3, Ce2O3, GdF3, and TbF3. In one embodiment, the rare-earth metal compound may be selected from YbF3, ScF3, TbF3, YbI3, ScI3, and TbI3, but is not limited thereto.

The alkali metal complex, the alkaline earth metal complex, and the rare-earth metal complex may include an alkali metal ion, and alkaline earth metal ion, and a rare-earth metal ion, respectively, as described above, and ligands respectively coordinated with the metal ion of the alkali metal complex, the alkaline earth metal complex, and the rare-earth metal complex may each independently be selected from a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyl oxazole, a hydroxyphenyl thiazole, a hydroxydiphenyl oxadiazole, a hydroxydiphenyl thiadiazole, a hydroxyphenyl pyridine, a hydroxyphenyl benzimidazole, a hydroxyphenyl benzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but are not limited thereto.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare-earth metal, an alkali metal compound, an alkaline earth metal compound, a rare-earth metal compound, an alkali metal complex, an alkaline earth metal complex, an rare-earth metal complex, or a combination thereof, as described above. In one or more embodiments, the electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare-earth metal, an alkali metal compound, an alkaline earth metal compound, a rare-earth metal compound, an alkali metal complex, an alkaline earth metal complex, a rare-earth metal complex, or a combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

The second electrode190may be disposed on the organic layer150. The second electrode190may be a cathode, which is an electron injection electrode, and in this regard, a material for forming the second electrode190may be selected from a metal, an alloy, an electrically conductive compound, and a combination thereof, each having a relatively low work function.

The second electrode190may include at least one selected from lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, and IZO, but is not limited thereto. The second electrode190may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

An organic light-emitting device20represented byFIG. 4includes a first capping layer210, the first electrode110, the organic layer150, and the second electrode190sequentially stacked in this stated order. An organic light-emitting device30represented byFIG. 5includes the first electrode110, the organic layer150, the second electrode190, and a second capping layer220sequentially stacked in this stated order. An organic light-emitting device40represented byFIG. 6includes the first capping layer210, the first electrode110, the organic layer150, the second electrode190, and the second capping layer220sequentially stacked in this stated order.

RegardingFIGS. 4 to 6, descriptions of the first electrode110, the organic layer150, and the second electrode190may be each independently the same as those provided herein in connection withFIG. 1.

In the organic light-emitting devices20and40, light emitted from the emission layer in the organic layer150may pass through the first electrode110(which may be a semi-transmissive electrode or a transmissive electrode) and through the first capping layer210to the outside. In the organic light-emitting devices30and40, light emitted from the emission layer in the organic layer150may pass through second electrode190(which may be a semi-transmissive electrode or a transmissive electrode) and through the second capping layer220to the outside.

The first capping layer210and the second capping layer220may improve the external luminous efficiency based on the principle of constructive interference.

The first capping layer210and the second capping layer220may be each independently a capping layer including an organic material, an inorganic capping layer including an inorganic material, or a composite capping layer including an organic material and an inorganic material.

At least one selected from the first capping layer210and the second capping layer220may include at least one material selected from carbocyclic compounds, heterocyclic compounds, amine-based compounds, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, alkali metal-based complexes, and alkaline earth metal-based complexes. The carbocyclic compound, the heterocyclic compound, and the amine-based compound may each independently be optionally substituted with a substituent containing at least one element selected from O, N, S, selenium (Se), silicon (Si), fluorine (F), chlorine (CI), bromine (Br), and iodine (I). In one embodiment, at least one selected from the first capping layer210and the second capping layer220may include an amine-based compound.

In one embodiment, at least one selected from the first capping layer210and the second capping layer220may include the compound represented by Formula 201 or the compound represented by Formula 202.

In one or more embodiments, at least one selected from the first capping layer210and the second capping layer220may include a compound selected from Compounds HT28 to HT33 and Compounds CP1 to CP5, but is not limited thereto:

Hereinbefore, the organic light-emitting device according to an embodiment has been described in connection withFIGS. 1-6. However, embodiments are not limited thereto.

The layers constituting the hole transport region, the emission layer, and the layers constituting the electron transport region may be formed in a specific region using one or more suitable methods such vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and/or laser-induced thermal imaging (LITI).

When the layers constituting the hole transport region, the emission layer, and the layers constituting the electron transport region are each independently formed by vacuum deposition, the vacuum deposition may be performed at a deposition temperature of about 100 to about 500° C., at a vacuum degree of about 10−8to about 10−3torr, and at a deposition rate of about 0.01 to about 100 Å/sec, depending on the compound to be included in each layer and the structure of each layer to be formed.

General Definition of Substituents

The term “C2-C60alkenyl group” as used herein may refer to a hydrocarbon group having at least one carbon-carbon double bond at one or more positions along the hydrocarbon chain of the C2-C60alkyl group (e.g., in the middle and/or at either terminus of the C2-C60alkyl group). Non-limiting examples thereof may include an ethenyl group, a propenyl group, and a butenyl group. The term “C2-C60alkenylene group” as used herein may refer to a divalent group having the same structure as the C2-C60alkenyl group.

The term “C2-C60alkynyl group” as used herein may refer to a hydrocarbon group having at least one carbon-carbon triple bond at one or more positions along the hydrocarbon chain of the C2-C60alkyl group (e.g., in the middle and/or at either terminus of the C2-C60alkyl group). Non-limiting examples thereof may include an ethynyl group and a propynyl group. The term “C2-C60alkynylene group” as used herein may refer to a divalent group having the same structure as the C2-C60alkynyl group.

The term “C6-C60aryl group” as used herein may refer to an aromatic monovalent group having 6 to 60 carbon atoms. The term “C6-C60arylene group” as used herein may refer to an aromatic divalent group having 6 to 60 carbon atoms. Non-limiting examples of the C6-C60aryl group may include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C6-C60aryl group and the C6-C60arylene group each independently include a plurality of rings, the respective rings may be fused to each other.

The term “C6-C60aryloxy group” as used herein may refer to a group represented by —OA102(where A102is the C6-C60aryl group). The term “C6-C60arylthio group” as used herein may refer to a group represented by —SA103(where A103is the C6-C60aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein may refer to a monovalent group that has a plurality of rings condensed (e.g., fused) to each other, and has only carbon atoms (e.g., 8 to 60 carbon atoms) as ring forming atoms, wherein the molecular structure as a whole is non-aromatic (e.g., does not have overall aromaticity). A non-limiting example of the monovalent non-aromatic condensed polycyclic group may be a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein may refer to a monovalent group that has two or more rings condensed (e.g., fused) with each other, and has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, other than carbon atoms (e.g., 1 to 60 carbon atoms), wherein the molecular structure as a whole is non-aromatic (e.g., does not have overall aromaticity). A non-limiting example of the monovalent non-aromatic condensed heteropolycyclic group may be a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed hetero-polycyclic group.

The term “C5-C60carbocyclic group” as used herein may refer to a monocyclic or polycyclic group having 5 to 60 carbon atoms only as ring-forming atoms. The term “C5-C60carbocyclic group” as used herein may refer to an aromatic carbocyclic group or a non-aromatic carbocyclic group. The term “C5-C60carbocyclic group” as used herein may refer to a ring (such as a benzene group), a monovalent group (such as a phenyl group), or a divalent group (such as a phenylene group). In one or more embodiments, depending on the number of substituents connected to the C5-C60carbocyclic group, the C5-C60carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C1-C60heterocyclic group” as used herein may refer to a group having the same structure as a C1-C60carbocyclic group, except that as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S is used in addition to carbon atoms (e.g., 1 to 60 carbon atoms).

The term “Ph” as used herein may refer to a phenyl group. The term “Me” as used herein may refer to a methyl group. The term “Et” as used herein may refer to an ethyl group. The term “ter-Bu” or “But” as used herein may refer to a tert-butyl group. The term “OMe” as used herein may refer to a methoxy group, and “D” may refer to deuterium.

The term “biphenyl group” as used herein may refer to a phenyl group substituted with a phenyl group. The “biphenyl group” may be a substituted phenyl group having a C6-C60aryl group as a substituent.

The term “terphenyl group” as used herein may refer to a phenyl group substituted with a biphenyl group. The “terphenyl group” may be a substituted phenyl group having a C6-C60aryl group substituted with a C6-C60aryl group as a substituent.

The symbols * and *′ as used herein, unless defined otherwise, refer to a binding site to an adjacent atom in a corresponding formula.

Hereinafter a compound and an organic light-emitting device according to one or more embodiments will be described in more detail with reference to Synthesis Examples and Examples. The expression “B was used instead of A” used in describing Synthesis Examples may refer to a molar equivalent of A being identical to a molar equivalent of B.

EXAMPLES

As a substrate and an anode, a Corning 15 Ohms per square centimeter (Ω/cm2) (150 Å) ITO glass substrate was cut to a size of 50 millimeters (mm)×50 mm×0.7 mm, sonicated by using isopropyl alcohol and deionized water for 5 minutes, respectively, and cleaned by exposure to ultraviolet rays with ozone. Then, the glass substrate was mounted on a vacuum deposition device.

TATC (100 Å), HAT-CN (50 Å), and NPB (100 Å) were sequentially deposited on the ITO anode to form a hole transport region.

HTL1 (100 Å) was deposited on the hole transport region to form a lower auxiliary layer, AND (ADN) and DPAVBi (the amount of DPAVBi was 5 percent by weight (wt %)) were co-deposited at a total thickness of 200 Å to form an emission layer, and Alq (50 Å) was deposited on the emission layer to form an upper auxiliary layer, to thereby form a first emission unit.

Compound 1 and Yb (the amount of Yb was 2 wt %) were co-deposited on the first emission unit at a total thickness of 150 Å to form an n-type charge generating layer, and HAT-CN (100 Å) was deposited on the n-type charge generating layer to form a p-type charge generating layer, to thereby form a first charge generating layer.

HTL1 (200 Å) was deposited on the first charge generating layer to form a lower auxiliary layer, CBP and (BT)2Ir(acac) (the amount of (BT)2Ir(acac) was 15 wt %) were co-deposited on the lower auxiliary layer at a total thickness of 200 Å to form an emission layer, and Alq (50 Å) was deposited on the emission layer to form an upper auxiliary layer, to thereby form a second emission unit.

Compound 1 and Yb (the amount of Yb was 2 wt %) were co-deposited on the second emission unit at a total thickness of 150 Å to form an n-type charge generating layer, and HAT-CN (100 Å) was deposited on the n-type charge generating layer to form a p-type charge generating layer, to thereby form a second charge generating layer.

NPB (100 Å) and HTL1 (100 Å) were sequentially deposited on the second charge generating layer to form a lower auxiliary layer, and AND (ADN) and DPAVBi (the amount of DPAVBi was 5 wt %) were co-deposited on the lower auxiliary layer at a total thickness of 200 Å to form an emission layer, to thereby form a third emission unit.

Alq (50 Å) was deposited on the third emission unit to form a first electron transport layer, Compound 1 and Yb (the amount of Yb was 2 wt %) were co-deposited on the first electron transport layer at a total thickness of 200 Å to form a second electron transport layer, and LiF (15 Å) was deposited on the second electron transport layer to form an electron injection layer, to thereby form an electron transport region.

Al (100 Å) was deposited on the electron transport region to form a cathode, thereby completing the manufacture of an organic light-emitting device.

Examples 2 and 3 and Comparative Example 1

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 1, except that the materials shown in Table 1 were used in the n-type charge generating layer and in the second electron transport layer.

Evaluation Example 1

The driving voltage (V), efficiency (cd/A), and lifespan (T97) of the organic light-emitting devices manufactured in Examples 1 to 3 and Comparative Example 1 were measured by using Keithley source-measure unit (SMU) 236 and a luminance meter PR650. The results thereof are shown in Table 1.

Referring to Table 1, it was found that the organic light-emitting devices of Examples 1 to 3 had a low driving voltage, high efficiency, and/or long lifespan, as compared with the organic light-emitting devices of Comparative Example 1.

As a substrate and an anode, a Corning 15 Ω/cm2(150 Å) ITO glass substrate was cut to a size of 50 mm×50 mm×0.7 mm, sonicated by using isopropyl alcohol and deionized water for 5 minutes, respectively, and cleaned by exposure to ultraviolet rays with ozone. Then, the glass substrate was mounted on a vacuum deposition device.

TATC (100 Å), HAT-CN (50 Å), and NPB (100 Å) were sequentially deposited on the ITO anode to form a hole transport region.

HTL1 (200 Å) was deposited on the hole transport region to form a lower auxiliary layer, CBP and (BT)2Ir(acac) (the amount of (BT)2Ir(acac) was 15 wt %) were co-deposited on the lower auxiliary layer at a total thickness of 200 Å to form an emission layer, and Alq (50 Å) was deposited on the emission layer to form an upper auxiliary layer, to thereby form a first emission unit.

Compound 1 and Yb (the amount of Yb was 2 wt %) were co-deposited on the first emission unit at a total thickness of 150 Å to form an n-type charge generating layer, and HAT-CN (100 Å) was deposited on the n-type charge generating layer to form a p-type charge generating layer, to thereby form a charge generating layer.

NPB (100 Å) and HTL1 (100 Å) were sequentially deposited on the charge generating layer to form a lower auxiliary layer, and AND (ADN) and DPAVBi (the amount of DPAVBi was 5 wt %) were co-deposited on the lower auxiliary layer at a total thickness of 200 Å to form an emission layer, to thereby form a second emission unit.

Alq (50 Å) was deposited on the second emission unit to form a first electron transport layer, Compound 4 was deposited on the first electron transport layer at a thickness of 200 Å to form a second electron transport layer, and LiF (15 Å) was deposited on the second electron transport layer to form an electron injection layer, to thereby form an electron transport region.

Al (100 Å) was deposited on the electron transport region to form a cathode, thereby completing the manufacture of an organic light-emitting device.

Examples 5 and 6 and Comparative Example 2

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 2, except that the materials shown in Table 2 were used in the n-type charge generating layer and in the second electron transport layer.

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 4, except that, in forming a first emission unit, HTL1 (200 Å) was deposited to form a lower auxiliary layer, CBP and (piq)2Ir(acac) (the amount of (piq)2Ir(acac) was 1 wt %) were co-deposited on the lower auxiliary layer at a total thickness of 100 Å, and then CBP and Ir(ppy)3(the amount of Ir(ppy)3was 7 wt %) were co-deposited at a total thickness of 200 Å to form an emission layer, and mCBP (50 Å) was deposited on the emission layer to form an upper auxiliary layer.

Examples 8 and 9 and Comparative Examples 3 and 4

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 7, except that the materials shown in Table 2 were used in the n-type charge generating layer and in the second electron transport layer.

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 4, except that, in forming a hole transport region, m-TDATA and F4-TCNQ (the amount of F4-TCNQ was 3 wt %) were co-deposited on the ITO anode at a total thickness of about 150 Å, and then NPB was deposited thereon at a thickness of 200 Å, instead of sequentially depositing TATC (100 Å), HAT-CN (50 Å), and NPB (100 Å) on the ITO anode.

Comparative Example 5

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 10, except that the materials shown in Table 2 were used in the n-type charge generating layer and in the second electron transport layer.

Evaluation Example 2

The driving voltage (V), efficiency (cd/A), and lifespan (T97) of the organic light-emitting devices manufactured in Examples 4 to 10 and Comparative Examples 2 to 5 were measured by using Keithley source-measure unit (SMU)236and a luminance meter PR650. The results thereof are shown in Table 2.

Referring to Table 2, it was found that the organic light-emitting devices of Examples 4 to 10 had a low driving voltage, high efficiency, and/or long lifespan, as compared with the organic light-emitting devices of respective Comparative Examples 2 to 5.

As described above, the organic light-emitting device according to embodiments of the present invention may have a low-driving voltage, improved efficiency, and long lifespan.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “over” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or “directly contacting” another element, there are no intervening elements present.