Organic semiconductive layer comprising phosphine oxide compounds

Abstract

The present invention relates to an organic semiconducting layer which is an electron transport layer and / or an electron injection layer and / or an n-type charge generating layer, wherein the organic semiconducting layer comprises at least one compound of the following formula (1), a phosphine oxide compound included therein, and an organic electroluminescent device comprising such layer and compound: In the above formula, R1 and R2 are each independently selected from C1 to C16 alkyl; Ar1 ​​is selected from C6 to C14 arylene or C3 to C12 heteroarylene; Ar2 is independently selected from C14 to C40 arylene or C8 to C40 heteroarylene; R3 is independently selected from H, C1 to C12 alkyl or C10 to C20 aryl; where each Ar1, Ar2 and R3 may each independently be substituted or unsubstituted with at least one C1 to C12 alkyl group; n is 0 or 1; in the case of n=0, m is 1; and in the case of n=1, m is 1 or 2.

Description

Technology Field

[0001] The present invention relates to an organic semiconducting layer, a phosphine oxide compound included therein, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs), which are self-emissive devices, possess a wide viewing angle, excellent contrast, fast response, high brightness, excellent driving voltage characteristics, and color reproducibility. A typical OLED comprises an anode, a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode, which are sequentially stacked on a substrate. In this regard, the HTL, EML, and ETL are thin films formed from organic and / or organometallic compounds.

[0003] When voltage is applied to the anode and cathode, holes injected from the anode electrode move to the EML through the HTL, and electrons injected from the cathode electrode move to the EML through the ETL. Holes and electrons recombine in the EML to generate excitons. When an exciton falls from the excited state to the ground state, light is emitted. The injection and flow of holes and electrons must be balanced, and accordingly, an OLED having the structure described above has excellent efficiency.

[0004] JP 2009 203203 discloses an anthracene derivative that is useful as a material for organic EL components, can be formed into a film by vapor deposition and coating, and exhibits a high glass transition temperature. A 9,10-bisphenylanthracene derivative having at least one aromatic heterocyclic group represented by the following general formula [3] as a substituent for the phenyl group and the anthracenylene group is provided:

[0005]

[0006] (In the above formula, R<sp> 21< / sp> to R <sp> 24< / sp> are each hydrogen atoms or substituents; R <sp> 25< / sp> is a hydrogen atom; X is O, S, or NR <sp> 26< / sp> is; R <sp> 26< / sp> (is a hydrogen atom or substituent).

[0007] However, there is a continuing demand to improve the performance of matrix compounds in OLEDs, particularly in the electron transport layer, electron injection layer, and n-type charge injection layer, to enable high efficiency, low operating voltage, and excellent stability.

[0008] Accordingly, the object of the present invention is to provide an organic electroluminescent device and a novel compound for use therein, which overcomes the disadvantages of the prior art in OLEDs, particularly fluorescent blue devices, characterized in, in particular, a reduction in operating voltage and / or improvement in external quantum efficiency (EQE) and / or improvement in lifespan.

[0009] This objective is achieved by an organic semiconducting layer that is an electron transport layer and / or an electron injection layer and / or an n-type charge generation layer, wherein the organic semiconducting layer comprises at least one compound of the following formula (1):

[0010]

[0011] In the above equation, R 1 and R 2 Each independently, C1 to C 16 Selected from alkyls;

[0012] Ar 1 C6 to C 14 Aryllene or C3 to C 12 Selected from heteroarylenes;

[0013] Ar 2 is independently, C 14 to C 40 Aryllene or C8 to C 40 Selected from heteroarylenes;

[0014] R 3 is independently H, C1 to C 12 alkyl or C 10 to C 20 Selected from Aril;

[0015] Here, each Ar 1 , Ar 2 and R 3 Each independently, at least one C1 to C 12 It may be substituted or unsubstituted with an alkyl group;

[0016] n is 0 or 1, and;

[0017] For n=0, m is 1; for n=1, m is 1 or 2.

[0018] Ar 2 C, a possible choice for 14 to C 40 Aryllene or C8 to C 40 It may be more desirable for the heteroarylene to comprise a conjugated system of at least 10 delocalized electrons.

[0019] In this regard, the term "conjugated system" should be understood as a system of different aromatic moiety (e.g., phenyl rings) that are connected to one another to form a condensed aromatic system (e.g., naphthyl groups) or connected to one another only by single bonds (e.g., biphenyl groups). Ar 2 An exemplary embodiment of an individual conjugated system of at least 10 delocalized electrons, which is a preferred choice for, is represented by the following chemical formula:

[0020]

[0021] Such a system must be regarded as a conjugated system of at least 10 delocalized electrons, despite the fact that it cannot be ruled out that the phenyl moiety may be twisted relative to one another, thereby lowering the conjugation of the system. That is, Ar (formed by condensed aromatic compounds or aromatic compounds joined together by only single bonds) 2 In Moiety's "conjugated system," sp 3 Hybridized carbon atoms do not exist. However, sp 3 - Hybridized carbon atoms are Ar 2 In the case of the substituents, they may exist in the form of, for example, alkyl substituents.

[0022] The term "alkyl" as used herein will include linear, as well as branched and cyclic alkyls. For example, C3-alkyls may be selected from n-propyl and iso-propyl. Likewise, C4-alkyls include n-butyl, 2-butyl, and t-butyl. Likewise, C6-alkyls include n-hexyl and cyclohexyl.

[0023] C n In this, the subscript number n refers to the total number of carbon atoms in individual alkyl, arylene, heteroarylene, or aryl groups.

[0024] As used herein, the term "aryl" will include phenyl (C6-aryl), fused aromatic compounds, e.g., naphthalene, anthracene, phenanthracene, tetracene, etc. Also includes biphenyl and oligo- or polyphenyls, e.g., terphenyl, etc. Additionally, any additional aromatic hydrocarbon substituents, e.g., fluorenyl, etc. Arylene, each heteroarylene, refers to groups to which two additional moiety is attached.

[0025] The term "heteroaryl" as used herein refers to an aryl group in which at least one carbon atom is substituted by a heteroatom, preferably by a heteroatom selected from N, O, S, B or Si.

[0026] C n - In heteroaryl, the subscript number n refers only to the number of carbon atoms excluding the number of heteroatoms. In this context, it is clear that the C3 heteroarylene group is an aromatic compound containing three carbon atoms, e.g., pyrazol, imidazole, oxazole, thiazole, etc.

[0027] In a preferred embodiment, Ar 2 C8 to C comprising at least one oxygen atom, at least one nitrogen atom, or at least one sulfur atom 40 It is selected from heteroarylene groups. Preferably, C8 to C 40 A heteroarylene group contains one nitrogen or one oxygen atom.

[0028] Ar 1 , Ar 2 and Ar 3 In this substituted case, the gi may include one or more substituents.

[0029] R 1 and R 2 It may be more desirable for to be selected identically. That is, R 1 and R 2 C1 to C that are identical 16 It may be preferable that they be alkyl groups. When R1 and R2 are selected identically, the synthesis of the compound of the present invention becomes simple.

[0030] In a more preferred embodiment, R 1 and R 2 Each independently, C1 to C 10Alkyl is selected from C1 to C8 alkyl, preferably C1 to C6 alkyl, more preferably C1 to C6 alkyl, and even more preferably C1 to C4 alkyl. The selection of shorter alkyl chains (i.e., chains having fewer carbon atoms) is advantageous for adjusting the physical and chemical properties of the compounds of the present invention, for example, evaporation temperature and solubility. C1 to C4 alkyl chains are preferred for thermal vacuum deposition processes, and C4 to C 12 Alkyl chains are preferred for processing from solution.

[0031] Ar 1 It may be more preferable to select from the group consisting of phenylene, biphenylene, naphthylene, fluorenylene, pyridylene, quinolinylene, and pyrimidinylene.

[0032] In this regard, Ar 1 This C6 to C 14 It is more desirable to select from arylene.

[0033] Better performance regarding the electronic properties of the layer of the present invention is due to the preferred Ar discussed above. 1 It was achieved when using energy.

[0034] In this regard, it is more preferable that n is 1. Ar 1 Compounds containing a group (n=1) have Ar with respect to related electronic properties 1 It is confirmed to be superior to compounds that do not contain a group (i.e., compounds where n is 0).

[0035] Likewise, several specific Ar 2 It was confirmed that the device achieved excellent electronic performance.

[0036] In another specific example, Ar 2 comprises at least 10 conjugated systems of delocalized electrons, and Ar 2 is non-substituted.

[0037] Ar 2comprises at least 10 conjugated systems of delocalized electrons, and Ar 2 is non-substituted, and R 3 It may be more desirable for this to be hydrogen.

[0038] Ar 2 comprises at least 10 conjugated systems of delocalized electrons, and Ar 2 is non-substituted, and R 3 It may be more desirable that this is hydrogen, n is 1, and m is 1.

[0039] In another preferred embodiment, Ar 2 It consists of a single unsubstituted condensed aromatic system or is represented by one of the following chemical formulas:

[0040]

[0041] In an aspect of the present invention, the condensed aromatic system consists of an annealed ring system or a spiro ring system. According to the present invention, a two-ring system is annealed when two ring members (usually carbon atoms) are simultaneously part of two rings. In an aspect of the present invention, the spiro compound contains at least two rings, and only one ring member (usually carbon atoms) is simultaneously part of both rings. In this regard, also, the group Ar 2 It is possible for it to be formed by a combination of more than one cyclic ring system and / or more than one spiro ring system. In this regard, an exemplary compound is the following compound (IVa) comprising a cyclic portion and a spiro portion. In this particular embodiment, it is provided that the condensed aromatic system does not comprise two different rings connected by only one single bond.

[0042] The condensed aromatic system may be selected from the group consisting of naphthylene, fluorenylene, 9,9'-spirobi[fluoren]-2,7-ylene, 9,9'-spirobi[fluoren]-3,6-ylene, spiro[fluoren-9,9'-xanthen]-2,7-ylene, spiro[fluoren-9,9'-xanthen]-3,6-ylene, benzofluorenylene, dibenzofluorenylene, anthracenylene, chrysenylene, pyrenylene, phenanthrylene, carbazoylene, benzoacrydinylene, dibenzoacrydinylene, dibenzofuranilene, naphthobenzofuranilene, dinaphthobenzofuranilene, dibenzothiophenylene, naphthobenzothiophenylene, and dinaphthiophenylene.

[0043] In particular, in this regard, Ar 2 It is preferable that a be selected from the group consisting of naphthylene, fluorenylene, anthracenylene, pyrenylene, phenanthrylene, carbazoylene, benzo[c]acridinylene, dibenzo[c,h]acridinylene, dibenzo[a,j]acridinylene, triazenylene, and benzofluorenylene, or from the group of the following chemical formulas (IVa) to (IVl):

[0044]

[0045]

[0046] Individual Ar of chemical formulas (IVa) to (IVp) 2 Giga, on the other hand, R 3 On that, and on the other hand, Ar respectively 1 Or the position connected to the P atom is the dotted line in the above structure It is indicated by the symbol of a chemical bond crossed by. Such connections can be made at any position of the individual aromatic rings indicated in this way.

[0047] In a preferred embodiment, Ar 2 is selected from the group consisting of anthracenylene, pyrenyllene, phenanthrylene, benzo[c]acridinylene, dibenzo[c,h]acridinylene and dibenzo[a,j]acridinylene.

[0048] Ar2 Ga C 14 to C 40 Arrylene, preferably, C 14 to C 22 It is particularly more desirable to be selected from arylene.

[0049] Preferably, Ar 2 Indolyl does not exist in.

[0050] R 3 These various selectable groups are identified as particularly advantageous for the electronic properties of the compound of the present invention in the layer of the present invention. In this regard, R 3 It is preferable that this be selected from H, phenyl, biphenyl, terphenyl, fluorenyl, naphthyl, phenanthyl, pyrenyl, carbazoyl, dibenzofuranyl, or dinaphthofuranyl, preferably from H, phenyl, biphenyl, or naphthyl.

[0051] The optimal performance is the above-mentioned desirable Ar 1 , Ar 2 and R 3 It is achieved by combining energy.

[0052] Ar 1 , Ar 2 and R 3 Each of these may be independently substituted or unsubstituted with at least one C1 to C6 alkyl group, preferably a C1 to C4 alkyl group.

[0053] Likewise, Ar 1 , Ar 2 and R 3 This non-substitution may be desirable.

[0054] Ar 1 , Ar 2 and R 3 By attaching substituents to the groups, the chemical and physical properties of individual compounds, for example, solubility, can be adjusted. C1 to C4 alkyl chains are preferred for thermal vacuum deposition processes, and C4 to C 12Alkyl chains are preferred for processing from solution.

[0055] For vacuum deposition, Ar 1 , Ar 2 and R 3 It may be desirable for the qi to be unsubstituted.

[0056] In one embodiment, n is 0 and m is 1. In the organic semiconducting layer according to the present invention, the preferred compound of formula (1) is selected from one of the following compounds 1a to 1i:

[0057]

[0058] In an additional embodiment, n is 1, m is 1, and R 3 is H. In the organic semiconducting layer according to the present invention, the preferred compound of formula (1) is selected from one of the following compounds 2a to 2gg:

[0059]

[0060]

[0061]

[0062]

[0063] In another embodiment, n is 1, m is 1, and R 3 C1 to C 12 alkyl or C 10 to C 20 It is an aryl. In the organic semiconducting layer according to the present invention, a preferred compound of formula (1) is selected from one of the following compounds 3a to 3pp:

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] In another embodiment, n is 1 and m is 2. In the organic semiconducting layer according to the present invention, the preferred compound of formula (1) is selected from one of the following compounds 4a to 4f:

[0071]

[0072] In another specific example, Ar 2 is selected particularly from bulky substituents. The bulky substituents of the type shown below have a rigid three-dimensional structure identified as particularly desirable. In the organic semiconducting layer according to the present invention, the preferred compound of formula (1) is selected from one of the following compounds 5a to 5c:

[0073]

[0074] In another embodiment, the organic semiconductor layer comprises at least one compound of the following formula (1a):

[0075]

[0076] In the above equation, R 1 and R 2 Each independently, C1 to C 16 Selected from alkyls;

[0077] Ar 1 C6 to C 14 Aryllene or C3 to C 12 Heteroarylene, preferably selected from phenylene or biphenylene;

[0078] R 3 is independently H, C1 to C 12 alkyl or C 10 to C 20 Selected from aryls, preferably, R 3 is H;

[0079] n is 1.

[0080] In a particularly preferred embodiment, the compound of formula (1) in the organic semiconducting layer according to the present invention is selected from one of the following compounds (a) to (q):

[0081]

[0082]

[0083] By selecting a compound of formula (1) from at least one of the above compounds (a) to (q), the best performance of the layer of the present invention was observed.

[0084] With respect to the organic semiconducting layer of the present invention as well as the compounds of the present invention, the compounds mentioned in the experimental section (referred to as "starting material and product" in the table) are most preferred.

[0085] Depending on the intended purpose, the organic semiconducting layer of the present invention may be doped. In a preferred embodiment, the organic semiconducting layer is doped, preferably electrically doped. The best results were achieved by the group of the following dopants.

[0086] In this regard, it is preferable that the organic semiconducting layer comprises an alkali organic complex and / or an alkali halide.

[0087] Preferably, the alkali organic complex and / or alkali halide is a lithium organic complex and / or lithium halide.

[0088] Suitable organic ligands for forming lithium organic complexes that can be used for electron transport layers are disclosed, for example, in US 2014 / 0048792 and in the literature [Kathirgamanathan, Poopathy; Arkley, Vincent; Surendrakumar, Sivagnanasundram; Chan, Yun F.; Ravichandran, Seenivasagam; Ganeshamurugan, Subramaniam; Kumaraverl, Muttulingam; Antipan-Lara, Juan; Paramaswara, Gnanamolly; Reddy, Vanga R., Digest of Technical Papers - Society for Information Display International Symposium (2010), 41(Bk. 1), 465-468].

[0089] Particularly desirable lithium organic complexes are shown in Table 1.

[0090] Table 1

[0091] Lithium organic complex suitable for use in organic semiconducting layers

[0092]

[0093]

[0094] The organic ligand of the lithium organic complex of the organic semiconducting layer may be selected from the group comprising quinolates, borates, phenolates, pyridinolates, or Schiff base ligands, or Table 1.

[0095] - Preferably, the lithium quinolate complex is of the following chemical formula (I), (II), or (III):

[0096]

[0097] (In the above formula,

[0098] A1 to A6 are selected from CH, CR, N, and O, either identically or independently;

[0099] R is selected, either identically or independently, from hydrogen, halogen, alkyl or aryl or heteroaryl having 1 to 20 carbon atoms; more preferably, A1 to A6 are CH;

[0100] - Preferably, the borate-based organic ligand is tetra(1H-pyrazole-1-yl)borate;

[0101] - Preferably, the phenolate is 2-(pyridine-2-yl)phenolate or 2-(diphenylphosphoryl)phenolate;

[0102] - Preferably, the lithium Schiff base has the following structure 100, 101, 102 or 103:

[0103]

[0104] - More preferably, the lithium organic complex is selected from the compounds of Table 1.

[0105] The lithium halide of the organic semiconducting layer can be selected from the group comprising LiF, LiCl, LiBr, or LiJ, and preferably, it can be LiF.

[0106] When an organic semiconducting layer containing a compound of chemical formula (1) is an electron transport layer or an electron injection layer and further includes a dopant selected from lithium organic complexes and / or lithium halides, particularly low operating voltage and high efficiency and lifetime are obtained.

[0107] In addition, it is desirable for the organic semiconducting layer to include a zero-valent metal dopant.

[0108] The zero-valent metal dopant is selected from alkali metals, alkaline earth metals, rare earth metals and / or group 3 transition metals. Preferably, the zero-valent metal dopant is selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Yb, Sm, Eu, Nd, Tb, Gd, Ce, La, Sc, and Y; more preferably, the zero-valent metal dopant is selected from the group consisting of Li, Na, Mg, Ca, Ba, and Yb; and even more preferably, the zero-valent metal dopant is selected from the group consisting of Li, Mg, Ba, and Yb.

[0109] When an organic semiconducting layer comprising a compound of formula (1) is an electron injection layer and / or an n-type charge generation layer and further comprises a dopant selected from zero-valent metal dopants, particularly low operating voltage and high efficiency and lifetime are obtained. For alternative purposes, it may be preferable for the organic semiconducting layer to be composed of at least one compound of formula (1) without any dopants. This is particularly true when there is no need for a dopant to be present in the layer of the present invention to operate the layer. In particular, the semiconducting organic layer may not contain alkali organic complexes and / or halides and / or zero-valent metals.

[0110] In one embodiment, the organic semiconducting layer is positioned between the anode and the cathode. Preferably, the layer is positioned closer to the cathode than to the anode. Preferably, the layer is adjacent to the cathode. Additionally, preferably, the organic semiconducting layer is arranged between the emission layer and the cathode. If a hole blocking layer is present, the organic semiconducting layer is arranged between the hole blocking layer and the cathode.

[0111] In one embodiment, the organic semiconducting layer is an electron transport layer. Preferably, the layer is adjacent to the cathode or, if present, the electron injection layer. In another embodiment, the organic semiconducting layer is an electron transport layer, and the layer is arranged adjacent to a charge generation layer.

[0112] In another embodiment, the organic semiconducting layer is an electron injection layer. Preferably, the layer is arranged between the cathode and the electron transport layer.

[0113] More preferably, the organic semiconducting layer is an electron transport layer and / or an electron injection layer.

[0114] In one embodiment, the organic semiconducting layer is an n-type charge generating layer (CGL). The n-type CGL is arranged between the anode and the cathode. Where at least one emitting layer is present, the n-type CGL is arranged between the first emitting layer and the second emitting layer. Preferably, the n-type CGL is adjacent to the emitting layer and / or the p-type CGL. More preferably, the n-type CGL is arranged between the emitting layer and the p-type CGL.

[0115] In other embodiments, the organic semiconducting layer is not an anode layer or a cathode layer. Unless otherwise noted, the terms anode (cathode), anode (cathode) layer, and anode (cathode) electrode are used herein as synonyms.

[0116] In another embodiment, the organic semiconducting layer is not an emitting layer. Preferably, the organic semiconducting layer does not have an emitter.

[0117] In a preferred embodiment, the organic semiconducting layer is in direct contact with the emission layer.

[0118] In another embodiment, the organic semiconducting layer is in direct contact with the cathode.

[0119] In another embodiment, the organic semiconducting layer is arranged between the emission layer and the electron injection layer and is in direct contact with both layers.

[0120] In another embodiment, the organic semiconducting layer is arranged between the emission layer and the n-type CGL and is in direct contact with both layers. In another embodiment, the organic semiconducting layer is arranged between the electron transport layer and the p-type CGL and is in direct contact with both layers.

[0121] In another embodiment, the organic semiconducting layer is arranged between the emission layer and the p-type CGL and is in direct contact with both layers.

[0122] In another embodiment, the organic semiconducting layer is arranged between the emission layer and the cathode layer and is in direct contact with both layers.

[0123] In another embodiment, the organic semiconducting layer is arranged between the electron transport layer and the cathode layer and is in direct contact with both layers.

[0124] The present objective is further achieved by an organic electroluminescent device (OLED) comprising an organic semiconducting layer of the present invention.

[0125] An organic light-emitting diode (OLED) can be a bottom-emission device or a top-emission device.

[0126] According to another embodiment, an organic electroluminescent device according to the present invention may comprise more than one emission layer, preferably two or three emission layers. An OLED comprising more than one emission layer is also described as a tandem OLED or a stacked OLED.

[0127] Another aspect relates to a device comprising at least one organic electroluminescent device (OLED). A device comprising an organic light-emitting diode is, for example, a display or a lighting panel.

[0128] In the present invention, the following terms defined, unless otherwise defined, will apply in the claims or elsewhere in the specification.

[0129] In the context of this specification, with respect to a matrix material, the term "different" or "distinguishable" means that the matrix material is different in its structural formula.

[0130] In the context of this specification, with respect to lithium compounds, the term "different" or "distinguishable" means that the lithium compounds differ in their structural formulas.

[0131] External quantum efficiency, also known as EQE, is measured in percentages (%).

[0132] The lifetime between the starting luminance and 97% of the original luminance, also referred to as LT, is measured in hours (h).

[0133] The operating voltage, also referred to as V, is 10 milliamperes (mA / cm²) per square centimeter. 2 It is measured as volts (V) in ).

[0134] The color space is described by the coordinates CIE-x and CIE-y (International Commission on Illumination 1931). In the case of blue emission, CIE-y is particularly important. The smaller the CIE-y, the deeper the blue color.

[0135] The most occupied molecular orbital, also named HOMO, and the least occupied molecular orbital, also named LUMO, are measured in electron volts (eV).

[0136] The terms "OLED," "organic electroluminescent device," and "organic light-emitting diode" are used simultaneously and have the same meaning.

[0137] The term “electron transport layer stack” as used in this specification comprises at least two electron transport layers or at least three electron transport layers.

[0138] The term "different compound" used in relation to matrix compounds means that the matrix compound differs from other matrix compounds in its chemical formula.

[0139] As used herein, “weight percent (percent by weight),” “weight%,” “weight% (% by weight),” and variations thereof refer to a composition, component, substance, or formulation obtained by dividing the weight of such component, substance, or formulation of an individual electron transport layer by the total weight of the individual electron transport layer and multiplying by 100. It is understood that the total weight% amount of all components, substances, and formulations of the individual electron transport layer and electron injection layer is selected such that it does not exceed 100 weight%.

[0140] As used herein, “volume percent (percent by volume),” “volume%,” “volume%,” and variations thereof refer to a composition, component, substance, or formulation as the volume of such component, substance, or reagent of an individual electron transport layer divided by the total volume of the individual electron transport layer and multiplied by 100. It is understood that the total volume% of all components, substances, and formulations of the cathode layer are selected such that the total volume% does not exceed 100 volume%.

[0141] All numerical values ​​are presumed to be modified by the term “about”, regardless of whether explicitly indicated herein. As used herein, the term “about” refers to a possible variation in numerical quantity. Regardless of whether modified by the term “about”, the claims include equivalents of quantities.

[0142] It should be noted that the singular forms (“a,” “an,” and “the”) used in this specification and the appended claims include plural references unless the context otherwise clearly indicates.

[0143] The terms "not present," "not containing," and "not including" do not exclude impurities. Impurities have no technical effect in relation to the purpose achieved by the present invention.

[0144] In the context that zero-valent metal dopants, alkali halides, alkali organic complexes, and / or emitters are not present in the electron transport layer, the term “not present” means that the so-called electron transport layer “not present” may contain zero-valent metal dopants, alkali halides, alkali organic complexes, and / or emitters in an amount of about 5 weight percent or less, preferably about 0.5 weight percent or less, and more preferably about 0.05 weight percent or less, and even more preferably about 0.005 weight percent or less, zero-valent metal dopants, alkali halides, alkali organic complexes, and / or emitters, and most preferably, zero-valent metal dopants, alkali halides, alkali organic complexes, and / or emitters are not present.

[0145] substrate

[0146] The substrate may be any substrate commonly used in the manufacture of organic light-emitting diodes. When light is emitted through the substrate, the substrate may be a transparent material, for example, a glass substrate or a transparent plastic substrate, having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness. When light is emitted through the top surface, the substrate may be a transparent or opaque material, for example, a glass substrate, a plastic substrate, a metal substrate, or a silicon substrate.

[0147] anode electrode

[0148] The anode electrode can be formed by depositing or sputtering a compound used to form the anode electrode. The compound used to form the anode electrode may be a high work-function compound to facilitate hole injection. The anode material may also be selected from a low work-function material (i.e., aluminum). The anode electrode may be a transparent or reflective electrode. Transparent conductive compounds, for example, indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO) may be used to form the anode electrode (120). The anode electrode (120) may also be formed using magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), silver (Ag), gold (Au), etc.

[0149] Hole injection layer

[0150] The hole injection layer (HIL) (130) can be formed on the anode electrode (120) by vacuum deposition, spin coating, printing, casting, slot-die coating, Langmuir-Blodgett (LB) deposition, etc. When the HIL (130) is formed using vacuum deposition, the deposition conditions may vary depending on the compound used to form the HIL (130) and the desired structure and thermal properties of the HIL (130). However, generally, the conditions for vacuum deposition include a deposition temperature of 100°C to 500°C, 10 -8 to 10 -3 It may include a pressure of Torr (1 Torr is 133.322 Pa), and a deposition rate of 0.1 to 10 nm / sec.

[0151] When the HIL (130) is formed using spin coating or printing, the coating conditions may vary depending on the compound used to form the HIL (130) and the desired structure and thermal properties of the HIL (130). For example, the coating conditions may include a coating speed of about 2000 rpm to about 5000 rpm and a heat treatment temperature of about 80°C to about 200°C. The heat treatment removes the solvent after the coating is performed.

[0152] HIL (130) can be formed from any compound commonly used to form HIL. Examples of compounds that can be used to form HIL (130) include phthalocyanine compounds, e.g., copper phthalocyanine (CuPc), 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), TDATA, 2T-NATA, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), and polyaniline) / poly(4-styrenesulfonate) (PANI / PSS).

[0153] HIL (130) may be a pure layer of p-dopant or may be selected from a hole-transport matrix compound doped with a p-dopant. Common examples of known redox-doped hole transport materials include copper phthalocyanine (CuPc) doped with tetrafluoro-tetracyanoquinone dimethane (F4TCNQ) with a LUMO level of about -5.2 eV and a HOMO level of about -5.2 eV; zinc phthalocyanine (ZnPc) doped with F4TCNQ (HOMO = -5.2 eV); and α-NPD (N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-benzidine) doped with F4TCNQ. There are α-NPDs doped with 2,2'-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (PD1) and α-NPDs doped with 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) (PD2). The dopant concentration can be selected from 1 to 20 weight%, more preferably from 3 weight% to 10 weight%.

[0154] The thickness of the HIL (130) may be in the range of about 1 nm to about 100 nm, and, for example, about 1 nm to about 25 nm. When the thickness of the HIL (130) is within this range, the HIL (130) may have excellent hole injection characteristics without a substantial increase in driving voltage.

[0155] Precision transport layer

[0156] A hole transport layer (HTL) (140) can be formed on the HIL (130) by vacuum deposition, spin coating, slot-die coating, printing, casting, Langmuir-Blodgett (LB) deposition, etc. When the HTL (140) is formed by vacuum deposition or spin coating, the conditions for deposition and coating may be similar to those for forming the HIL (130). However, the conditions for vacuum or solution deposition may vary depending on the compound used to form the HTL (140).

[0157] HTL (140) can be formed from any compound commonly used to form HTL. Compounds suitable for use are described, for example, in the literature [Yasuhiko Shirota and Hiroshi Kageyama, Chem. Rev. 2007, 107, 953-1010], which is incorporated by reference. Examples of compounds that can be used to form HTL (140) include carbazole derivatives, for example, N-phenylcarbazole or polyvinylcarbazole; amine derivatives having an aromatic condensed ring, for example, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD), or N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (alpha-NPD); and triphenylamine-based compounds, for example, 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA). Among these compounds, TCTA can transport holes and inhibit excitons from diffusing into the EML.

[0158] The thickness of the HTL (140) may be in the range of about 5 nm to about 250 nm, preferably about 10 nm to about 200 nm, also about 20 nm to about 190 nm, also about 40 nm to about 180 nm, also about 60 nm to about 170 nm, also about 80 nm to about 160 nm, also about 100 nm to about 160 nm, also about 120 nm to about 140 nm. The preferred thickness of the HTL (140) may be 170 nm to 200 nm.

[0159] When the thickness of the HTL (140) is within this range, the HTL (140) can have excellent hole transport characteristics without a substantial increase in driving voltage.

[0160] Electromagnetic blocking layer

[0161] The function of the electron blocking layer (EBL) (150) is to prevent electrons from being transferred from the emission layer to the hole transport layer, thereby confining the electrons to the emission layer. By doing so, efficiency, operating voltage, and / or lifetime are improved. Typically, the electron blocking layer comprises a triarylamine compound. The triarylamine compound may have a LUMO level closer to the vacuum level than the LUMO of the hole transport layer. The electron blocking layer may have a HOMO level further from the vacuum level compared to the HOMO level of the hole transport layer. The thickness of the electron blocking layer is selected from 2 to 20 nm.

[0162] The electron blocking layer may include a compound of the following chemical formula Z:

[0163]

[0164] In the chemical formula Z,

[0165] CY1 and CY2 are identical or different from each other and each independently represents a benzene cycle or a naphthalene cycle, and

[0166] Ar1 to Ar3 are identical or different from one another and are each independently selected from the group consisting of hydrogen; a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; and a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms, and

[0167] Ar4 is selected from the group consisting of substituted or unsubstituted phenyl groups, substituted or unsubstituted biphenyl groups, substituted or unsubstituted terphenyl groups, substituted or unsubstituted triphenylene groups, and substituted or unsubstituted heteroaryl groups having 5 to 30 carbon atoms, and

[0168] L is a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.

[0169] In the case where the electron blocking layer has a high triplet level, it can also be described as a triplet control layer.

[0170] The function of the triplet control layer is to reduce the quenching of the triplets when a phosphorescent green or blue emission layer is used. By doing so, higher efficiency of light emission from the phosphorescent emission layer can be achieved. The triplet control layer is selected from triarylamine compounds having a triplet level higher than the triplet level of the phosphorescent emitter in the adjacent emission layer. Suitable triplet control layers, in particular, triarylamine compounds are described in EP 2 722 908 A1.

[0171] Emission layer (EML)

[0172] EML (150) can be formed on HTL by vacuum deposition, spin coating, slot-die coating, printing, casting, LB, etc. When EML is formed using vacuum deposition or spin coating, the conditions for deposition and coating may be similar to those for forming HIL. However, the conditions for deposition and coating may vary depending on the compound used to form EML.

[0173] The release layer (EML) may be formed from a combination of a host and a dopant. Examples of hosts include Alq3, 4,4'-N,N'-dacarbazole-biphenyl (CBP), poly(n-vinylcarbazole) (PVK), 9,10-di(naphthalene-2-yl)anthracene (ADN), 4,4',4"-tris(carbazole-9-yl)-triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBI), tertiary-butyl-9,10-di-2-naphthylanthracene (TBADN), distyrylarylene (DSA), bis(2-(2-hydroxyphenyl)benzothiazolate)zinc (Zn(BTZ)2), the following E3, the following AND, the following compound 1, and the following compound 2:

[0174]

[0175] The dopant may be a phosphorescent or fluorescent emitter. Phosphorescent emitters and emitters that emit light via a thermally activated delayed fluorescence (TADF) mechanism are preferred due to their higher efficiency. The emitter may be a small molecule or a polymer.

[0176] Examples of red dopants include, but are not limited to, PtOEP, Ir(piq)3, and Btp 2lr(acac). These compounds are phosphorescent emitters, but fluorescent red dopants may also be used.

[0177]

[0178] Examples of phosphorescent green dopants include Ir(ppy)3 (ppy = phenylpyridine), Ir(ppy)2 (acac), and Ir(mpyp)3 shown below. Compound 3 is an example of a fluorescent green emitter, and its structure is as shown below:

[0179]

[0180] Examples of phosphorescent blue dopants include F2Irpic, (F2ppy)2Ir(tmd) and Ir(dfppz)3, and ter-fluorene, the structures of which are shown below. 4,4'-bis(4-diphenylaminostyryl)biphenyl (DPAVBi), 2,5,8,11-tetra-tert-butylperylene (TBPe), and the following compound 4 are examples of fluorescent blue dopants.

[0181]

[0182] The amount of dopant may be in the range of about 0.01 to about 50 parts by weight based on 100 parts by weight of the host. Alternatively, the emission layer may be made of a light-emitting polymer. The EML may have a thickness of about 10 nm to about 100 nm, for example, about 20 nm to about 60 nm. When the thickness of the EML is within this range, the EML can have excellent light emission without a substantial increase in driving voltage.

[0183] Hole Blocking Layer (HBL)

[0184] When the EML contains a phosphorescent dopant, a hole blocking layer (HBL) can be formed on the EML by using vacuum deposition, spin coating, slot-die coating, printing, casting, LB deposition, etc. to prevent the diffusion of triplet excitons or holes into the ETL.

[0185] When HBL is formed using vacuum deposition or spin coating, the conditions for deposition and coating may be similar to those for the formation of HIL. However, the conditions for deposition and coating may vary depending on the compound used to form the HBL. Any compound commonly used to form HBL may be used. Examples of compounds for forming HBL include oxadiazole derivatives, triazole derivatives, and phenanthroline derivatives.

[0186] HBL can have a thickness of about 5 nm to about 100 nm, for example, about 10 nm to about 30 nm. When the thickness of the HBL is within this range, the HBL can have excellent hole-blocking properties without a substantial increase in driving voltage.

[0187] Compounds used in the electron transport layer (ETL)

[0188] The OLED according to the present invention may not contain an electron transport layer (ETL). However, the OLED according to the present invention may optionally contain an electron transport layer (ETL).

[0189] According to various embodiments, the OLED may include an electron transport layer, or an electron transport layer stack comprising at least a first electron transport layer and at least a second electron transport layer.

[0190] According to various embodiments of the OLED of the present invention, the electron transport layer may comprise at least one matrix compound. Preferably, the matrix compound is an organic compound. More preferably, the matrix compound is a covalent organic matrix compound. In other words, the matrix compound comprises covalent bonds. It should be understood that "substantially covalent" means a compound comprising elements bonded together by almost covalent bonds.

[0191] According to various embodiments of the OLED, the matrix compound is

[0192] - Anthracene-based compounds or heteroaryl-substituted anthracene-based compounds, preferably, 2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole and / or N4,N4"-di(naphthalene-1-yl)-N4,N4"-diphenyl-[1,1':4',1"-terphenyl]-4,4"-diamine;

[0193] - Phosphine oxide-based compounds, preferably, (3-(dibenzo[c,h]acridine-7-yl)phenyl)diphenylphosphine oxide and / or phenyl bis(3-(pyrene-1-yl)phenyl)phosphine oxide and / or 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphine-3-oxide; or

[0194] - Substituted phenanthroline compounds, preferably selected from 2,4,7,9-tetraphenyl-1,10-phenanthroline, 4,7-diphenyl-2,9-di-p-tolyl-1,10-phenanthroline, or 2,9-di(biphenyl-4-yl)-4,7-diphenyl-1,10-phenanthroline.

[0195] According to various embodiments of the OLED, the matrix compound of the electron transport layer is preferably,

[0196] - Phosphine oxide-based compounds, preferably, (3-(dibenzo[c,h]acridine-7-yl)phenyl)diphenylphosphine oxide, 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphine-3-oxide and / or phenyl bis(3-(pyrene-1-yl)phenyl)phosphine oxide; or

[0197] - Substituted phenanthroline compounds, preferably selected from 2,4,7,9-tetraphenyl-1,10-phenanthroline, 4,7-diphenyl-2,9-di-p-tolyl-1,10-phenanthroline, or 2,9-di(biphenyl-4-yl)-4,7-diphenyl-1,10-phenanthroline.

[0198] According to various embodiments of the OLED, the matrix compound of the electron transport layer is more preferably,

[0199] - A phosphine oxide-based compound, preferably selected from (3-(dibenzo[c,h]acridine-7-yl)phenyl)diphenylphosphine oxide, 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphine-3-oxide and / or phenyl bis(3-(pyrene-1-yl)phenyl)phosphine oxide.

[0200] According to various embodiments of the OLED of the present invention, the thickness of the electron transport layer may be in the range of about ≥ 0.5 nm to about ≤ 95 nm, preferably about ≥ 3 nm to about ≤ 80 nm, more preferably about ≥ 5 nm to about ≤ 60 nm, also preferably about ≥ 6 nm to about ≤ 40 nm, further preferably about ≥ 8 nm to about ≤ 20 nm, and more preferably about ≥ 10 nm to about ≤ 18 nm.

[0201] According to various embodiments of the OLED of the present invention, the thickness of the electron transport layer stack may be in the range of about ≥ 25 nm to about ≤ 100 nm, preferably about ≥ 30 nm to about ≤ 80 nm, more preferably about ≥ 35 nm to about ≤ 60 nm, and more preferably about ≥ 36 nm to about ≤ 40 nm.

[0202] According to one embodiment of the OLED, the electron transport layer comprises about ≥ 50 wt% to about ≤ 60 wt% of a first lithium halide or a first lithium organic complex, and about ≤ 50 wt% to about ≥ 40 wt% of the following matrix compound:

[0203] - Phosphine oxide-based compounds, preferably, (3-(dibenzo[c,h]acridine-7-yl)phenyl)diphenylphosphine oxide, 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphine-3-oxide and / or phenyl bis(3-(pyrene-1-yl)phenyl)phosphine oxide; or

[0204] - Substituted phenanthroline compound, preferably, 2,4,7,9-tetraphenyl-1,10-phenanthroline, 4,7-diphenyl-2,9-di-p-tolyl-1,10-phenanthroline, or 2,9-di(biphenyl-4-yl)-4,7-diphenyl-1,10-phenanthroline.

[0205] A light-emitting diode (OLED) may include at least two electrodes, an anode and a cathode electrode.

[0206] The electron transport layer / s or electron transport layer stack is not an electrode. The electron transport layer / s or electron transport layer is sandwiched between two electrodes, that is, sandwiched between the anode and the second cathode.

[0207] The ETL may optionally be formed on the EML, or on the HBL when the HBL is formed. The ETL comprises a first layer comprising a first lithium halide or a first lithium organic complex; and a second electron transport layer comprising an optional second lithium halide or a second lithium organic complex, wherein the optional first lithium organic complex is not identical to the second lithium organic complex, and the first lithium halide is not identical to the second lithium halide.

[0208] The ETL comprises a first layer comprising a first matrix compound and a lithium halide or lithium organic complex; and a second electron transport layer comprising an optional second matrix compound and a metal dopant selected from the group comprising alkali metals, alkaline earth metals and rare earth metals.

[0209] The ETL comprises a first layer comprising a first matrix compound and a lithium halide or lithium organic complex; and a second electron transport layer comprising an optional second matrix compound and having no dopant.

[0210] The ETL may have a stacked structure, preferably a stacked structure of two ETL layers, so that electron injection and transport can be balanced and holes can be efficiently blocked. In a conventional OLED, since the amounts of electrons and holes vary over time, the number of excitons generated in the emission zone may decrease after driving is initiated. Consequently, carrier balance may not be maintained, which reduces the lifespan of the OLED.

[0211] However, in ETL, the first and second layers may have similar or identical energy levels, thereby allowing the carrier balance to be maintained uniformly while controlling the electron transport rate.

[0212] A matrix compound for an electronic layer that can be suitably used is selected from the group comprising anthracene compounds, preferably 2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole.

[0213] Anthracene compounds that can be used as matrix materials are disclosed in US 6878469 B.

[0214] Other matrix compounds that can be used are diphenylphosphine oxide, preferably (3-(dibenzo[c,h]acridine-7-yl)phenyl)diphenylphosphine oxide, phenylbis(3-(pyrene-1-yl)phenyl)phosphine oxide, 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphine-3-oxide, and phenyldi(pyrene-1-yl)phosphine oxide.

[0215] Diphenylphosphine oxide compounds that can be used as matrix materials are disclosed in EP 2395571 A1, WO2013079217 A1, EP 13187905, EP13199361 and JP2002063989 A1.

[0216] Other suitable matrix compounds that can be used are phenanthroline compounds, preferably selected from the group comprising 2,4,7,9-tetraphenyl-1,10-phenanthroline, 4,7-diphenyl-2,9-di-p-tolyl-1,10-phenanthroline, and 2,9-di(biphenyl-4-yl)-4,7-diphenyl-1,10-phenanthroline. Phenanthroline compounds that can be used as matrix materials are disclosed in EP 1786050 A1.

[0217] The matrix compound of the electron transport layer may be a compound that efficiently transports electrons, for example, an anthracene-based compound, a diphenylphosphine oxide-based compound, or a phenanthroline-based compound, preferably, the matrix compounds mentioned in Table 4. For example, the matrix compound of the electron transport layer may be selected from the group consisting of the following compounds 5, the compound represented by Formula 2, and the compound represented by Formula 3:

[0218]

[0219] In Chemical Formulas 2 and 3, R1 to R6 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a substituted or unsubstituted C1-C 30 Alkyl groups, substituted or unsubstituted C1-C 30 Alkoxy groups, substituted or unsubstituted C1-C 30 Acyl group, substituted or unsubstituted C2-C 30 alkenyl group, substituted or unsubstituted C2-C 30 alkynyl group, substituted or unsubstituted C6-C 30 Aryl groups, or substituted or unsubstituted C3-C 30 It is a heteroaryl group. At least two adjacent R1 to R6 groups are optionally bonded to each other to form a saturated or unsaturated ring. L1 is bonded, substituted, or unsubstituted C1-C 30 Alkylene groups, substituted or unsubstituted C6-C 30 Aryllene group, or substituted or unsubstituted C3-C 30 It is a heteroarylene group. Q1 to Q9 are each independently hydrogen atoms, substituted or unsubstituted C6-C 30 Aryl groups, or substituted or unsubstituted C3-C 30 It is a heteroaryl group, and "a" is an integer from 1 to 10.

[0220] For example, R1 to R6 can each be independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenyl group, a naphthyl group, anthryl group, a pyridinyl group, and a pyrazinyl group.

[0221] In particular, in Formula 2 and / or Formula 3, R1 to R4 may each be a hydrogen atom, and R5 may be selected from the group consisting of a halogen atom, a hydroxyl group, a cyano group, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenyl group, a naphthyl group, anthryl group, a pyridinyl group, and a pyrazinyl group. Additionally, in Formula 3, R1 to R6 may each be a hydrogen atom.

[0222] For example, in Formula 2 and / or Formula 3, Q1 to Q9 are each independently a hydrogen atom, a phenyl group, a naphthyl group, anthryl group, a pyridinyl group, and a pyrazinyl group. In particular, in Formula 2 and / or Formula 3, Q1, Q3 to Q6, Q8 and Q9 are hydrogen atoms, and Q2 and Q7 can each be independently selected from the group consisting of a phenyl group, a naphthyl group, anthryl group, a pyridinyl group, and a pyrazinyl group.

[0223] For example, L1 may be selected from the group consisting of a phenylene group, a naphthylene group, anthrylene group, a pyridinylene group, and a pyrazinylene group in Formula 2 and / or Formula 3. In particular, L1 may be a phenylene group or a pyridinylene group. For example, "a" may be 1, 2, or 3.

[0224] The matrix compound for the ETL layer may be further selected from the following compounds 5, 6, or 7:

[0225]

[0226] Table 2

[0227] Chemical structure of a matrix material suitable for use for ETL and / or EIL layers

[0228]

[0229]

[0230] The electron transport layer may include a lithium halide or a lithium organic complex.

[0231] Suitable organic ligands for forming lithium organic complexes that can be used for electron transport layers are disclosed, for example, in US 2014 / 0048792 and in the literature [Kathirgamanathan, Poopathy; Arkley, Vincent; Surendrakumar, Sivagnanasundram; Chan, Yun F.; Ravichandran, Seenivasagam; Ganeshamurugan, Subramaniam; Kumaraverl, Muttulingam; Antipan-Lara, Juan; Paramaswara, Gnanamolly; Reddy, Vanga R., Digest of Technical Papers - Society for Information Display International Symposium (2010), 41(Bk. 1), 465-468].

[0232] The organic ligand of the lithium organic complex of the electron transport layer may be selected from the group comprising quinolates, borates, phenolates, pyridinolates, or Schiff base ligands, or Table 1.

[0233] - Preferably, the lithium quinolate complex has the following chemical formula (III):

[0234]

[0235] (In the above formula,

[0236] A1 to A6 are selected from CH, CR, N, and O, either identically or independently;

[0237] R is selected, either identically or independently, from hydrogen, halogen, alkyl or aryl or heteroaryl having 1 to 20 carbon atoms, and more preferably, A1 to A6 are CH;

[0238] - Preferably, the borate-based organic ligand is tetra(1H-pyrazole-1-yl)borate;

[0239] - Preferably, the phenolate is 2-(pyridine-2-yl)phenolate or 2-(diphenylphosphoryl)phenolate;

[0240] - Preferably, the lithium Schiff base has the following structure 100, 101, 102 or 103:

[0241]

[0242] - More preferably, the lithium organic complex is selected from the compounds of Table 1.

[0243] The lithium halide of the electron transport layer is selected from the group comprising LiF, LiCl, LiBr, or LiJ, and preferably, may be LiF.

[0244] ETL can be formed on EML by vacuum deposition, spin coating, slot-die coating, printing, casting, etc. When ETL is formed by vacuum deposition or spin coating, the deposition and coating conditions may be similar to those for forming HIL (130). However, the deposition and coating conditions may vary depending on the compound used to form ETL.

[0245] Electron injection layer (EIL)

[0246] Any EIL capable of facilitating electron injection from the cathode can be formed on the ETL, preferably directly on the electron transport layer. Examples of materials for forming the EIL include LiQ, LiF, NaCl, CsF, Li2O, BaO, Ca, Ba, Yb, and Mg, which are known in the art. The deposition and coating conditions for forming the EIL are similar to those for forming the HIL, but the deposition and coating conditions may vary depending on the material used to form the EIL.

[0247] The thickness of the EIL may be in the range of about 0.1 nm to 10 nm, for example, in the range of 0.5 nm to 9 nm. When the thickness of the EIL is within this range, the EIL can have satisfactory electron-injection properties without a substantial increase in driving voltage.

[0248] cathode electrode

[0249] A cathode electrode is formed on the EIL, if present. The cathode electrode may be a cathode that is an electron-injection electrode. The cathode electrode may be formed of a metal, an alloy, an electrically conductive compound, or a mixture thereof. The cathode electrode may have a low work function. For example, the cathode electrode may be formed of lithium (Li), magnesium (Mg), aluminum (Al), aluminum (Al)-lithium (Li), calcium (Ca), barium (Ba), ytterbium (Yb), magnesium (Mg)-indium (In), magnesium (Mg)-silver (Ag), etc. Additionally, the cathode electrode may be formed of a transparent conductive material, for example, ITO or IZO.

[0250] The thickness of the cathode electrode may be in the range of about 5 nm to 1000 nm, for example, in the range of 10 nm to 100 nm. When the cathode electrode is in the range of 5 nm to 50 nm, the electrode will be transparent even if a metal or metal alloy is used.

[0251] The cathode electrode is not an electron injection layer or an electron transport layer.

[0252] Since the ETL layers have similar or identical energy levels, electron injection and transport can be controlled, and holes can be efficiently blocked. Accordingly, the OLED can have a long lifespan.

[0253] charge generation layer

[0254] The charge generation layer (CGL) (140) is composed of a double layer.

[0255] More specifically, the charge generation layer may be a pn junction charge generation layer formed by joining an n-type charge generation layer (185) and a p-type charge generation layer (135). The pn junction charge generation layer generates charges or separates them into holes and electrons; and injects the charges into individual light-emitting layers. In other words, the n-type charge generation layer (185) provides electrons to the first light-emitting layer (150) near the anode, and the p-type charge generation layer (135) provides holes to the second light-emitting layer (151) near the cathode (190), thereby further improving the luminous efficiency of the organic light-emitting device with multiple light-emitting layers and, at the same time, lowering the driving voltage.

[0256] The p-type charge generating layer (135) may be composed of a metal or organic material doped with a p-type dopant. Here, the metal may be a metal selected from the group consisting of Al, Cu, Fe, Pb, Zn, Au, Pt, W, In, Mo, Ni, and Ti, or an alloy consisting of two or more of them. Additionally, the host used for the p-type dopant and the p-type doped organic material may be a conventional material. For example, the p-type dopant may be selected from the group consisting of tetrafluor-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), derivatives of tetracyanoquinodimethane, radialene derivatives, iodine, FeCl3, FeF3, and SbCl5. Additionally, the host may be selected from the group consisting of N,N'-di(naphthalene-1-yl)-N,N-diphenyl-benzidine (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1-biphenyl-4,4'-diamine (TPD), and N,N',N'-tetranaphthyl-benzidine (TNB).

[0257] The n-type charge generating layer (185) may be composed of an n-type doped metal or organic material. The metal may be selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy, and Yb. Additionally, the host used for the n-type dopant and the n-type doped organic material may be a conventional material. For example, the n-type dopant may be an alkali metal, an alkali metal compound, an alkaline earth metal, or an alkaline earth metal compound. More specifically, the n-type dopant may be selected from the group consisting of Cs, K, Rb, Mg, Na, Ca, Sr, Eu, and Yb. The host material may be selected from the group consisting of tris(8-hydroxyquinoline)aluminum, triazine, hydroxyquinoline derivatives, benzazole derivatives, and silol derivatives.

[0258] In a preferred embodiment, the host material is selected from compounds of formula (1).

[0259] In another preferred embodiment, the electron transport layer comprises a compound of formula (1) and an n-type charge generating layer (185), which is arranged adjacent to the electron transport layer. In one example, the n-type charge generating layer may comprise a compound of formula X below:

[0260]

[0261] In the above equation, A 1 To A 6 Each may be hydrogen, a halogen atom, nitrile (-CN), nitro (-NO2), sulfonyl (-SO2R), sulfoxide (-SOR), sulfonamide (-SO2NR), sulfonate (-SO3R), trifluoromethyl (-CF3), ester (-COOR), amide (-CONHR or -CONRR'), substituted or unsubstituted straight-chain or branched-chain C1-C12 alkoxy, substituted or unsubstituted straight-chain or branched-chain C1-C12 alkyl, substituted or unsubstituted straight-chain or branched-chain C2-C12 alkenyl, substituted or unsubstituted aromatic or non-aromatic heterocycle, substituted or unsubstituted aryl, substituted or unsubstituted mono- or di-arylamine, substituted or unsubstituted aralkylamine, etc. Herein, each of R and R' is a substituted or unsubstituted C1-C 60 It may be an alkyl, a substituted or unsubstituted aryl, or a substituted or unsubstituted 5- to 7-membered heterocycle, etc.

[0262] An n-type charge generating layer comprising the following CNHAT is particularly preferred:

[0263]

[0264] The p-type charge generating layer is arranged on top of the n-type charge generating layer. As a material for the p-type charge generating layer (135), an arylamine-based compound may be used. One embodiment of an arylamine-based compound includes a compound of the following formula Y:

[0265]

[0266] In the above formula, Ar1, Ar2, and Ar3 are each independently hydrogen or hydrocarbon groups.

[0267] Here, at least one of Ar1, Ar2, and Ar3 may include an aromatic hydrocarbon substituent, and each substituent may be the same or may consist of different substituents. When Ar1, Ar2, and Ar3 are not aromatic hydrocarbons, they may be hydrogen; straight-chain, branched-chain, or cyclic aliphatic hydrocarbons; or heterocyclic groups including N, O, S, or Se.

[0268] Organic light-emitting diode (OLED)

[0269] According to another aspect of the present invention, an organic light-emitting diode (OLED) is provided, comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer, a hole transport layer, an emission layer, and a cathode electrode.

[0270] According to another aspect of the present invention, an organic light-emitting diode (OLED) is provided, comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer, a hole transport layer, an electron blocking layer, an emission layer, a hole blocking layer, and a cathode electrode.

[0271] According to another aspect of the present invention, an organic light-emitting diode (OLED) is provided, comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer, a hole transport layer, and an electron blocking layer, an emission layer, a hole blocking layer, an electron transport layer, and a cathode electrode.

[0272] According to another aspect of the present invention, an organic light-emitting diode (OLED) is provided, comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer, a hole transport layer, an electron blocking layer, an emission layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode electrode.

[0273] According to various embodiments of the present invention, an organic light-emitting diode (OLED) is provided that further comprises an electron injection layer formed between an electron transport layer and a cathode electrode.

[0274] According to various embodiments of the OLED of the present invention, the OLED may not include an electron injection layer.

[0275] According to various embodiments of the OLED of the present invention, the OLED may not include an electron transport layer.

[0276] According to various embodiments of the OLED of the present invention, the OLED may not include an electron transport layer and an electron injection layer.

[0277] According to one embodiment, the OLED may include a layer structure of a substrate arranged adjacent to an anode electrode, wherein the anode electrode is arranged adjacent to a first hole injection layer, the first hole injection layer is arranged adjacent to a first hole transport layer, the first hole transport layer is arranged adjacent to a first electron blocking layer, the first electron blocking layer is arranged adjacent to a first emission layer, the first emission layer is arranged adjacent to a first electron transport layer, the first electron transport layer is arranged adjacent to an n-type charge generation layer, the n-type charge generation layer is arranged adjacent to a p-type charge generation layer, the p-type charge generation layer is arranged adjacent to a second hole injection layer, the second hole injection layer is arranged adjacent to a second hole transport layer, the second hole transport layer is arranged adjacent to a second electron blocking layer, the second electron blocking layer is arranged adjacent to a second emission layer, and between the second emission layer and the cathode electrode, an optional electron transport layer and / or an optional injection layer are arranged.

[0278] According to another aspect of the present invention, a method for manufacturing an organic light-emitting diode (OLED),

[0279] - At least one deposition source, preferably two deposition sources, and more preferably, at least three deposition sources; and / or

[0280] - Deposition via vacuum thermal evaporation; and / or

[0281] - A method is provided using deposition through solution processing (preferably, processing is selected from spin-coating, printing, casting, and / or slot-die coating).

[0282] According to another embodiment, a method comprising the following steps is provided:

[0283] - A step of forming an anode (120) on a substrate (110),

[0284] - A step of forming an emission layer (150) on an anode (120),

[0285] - A step of forming an electron transport layer (160) on an emission layer (150),

[0286] - A step of forming a cathode electrode (190) on an electron transport layer (160),

[0287] - A step of forming an optional hole injection layer (130), a hole transport layer (140), an electron blocking layer (145), an emission layer (150), and a hole blocking layer in such order between at least the anode (120) and the electron transport layer (160),

[0288] - A step of arranging an arbitrary electron injection layer (180) between an electron transport layer (160) and a cathode (190).

[0289] Finally, the present objective is achieved by a compound of the following chemical formula (1):

[0290]

[0291] In the above equation, R 1 and R 2Each independently, C1 to C 16 Selected from alkyls;

[0292] Ar 1 C6 to C 14 Aryllene or C3 to C 12 Selected from heteroarylenes;

[0293] Ar 2 C independently comprises at least 14 conjugated systems of delocalized electrons. 14 to C 40 C8 to C comprising arylene or a conjugated system of at least 14 delocalized electrons 40 Selected from heteroarylenes;

[0294] R 3 is independently H, C1 to C 12 alkyl or C 10 to C 20 Selected from Aril;

[0295] Ar 1 , Ar 2 and R 3 Each independently, at least one C1 to C 12 It may be substituted or unsubstituted with an alkyl group;

[0296] n is 0 or 1, and;

[0297] For n=0, m is 1; for n=1, m is 1 or 2;

[0298] Here, R 1 and R 2 α is isopropyl, n is 0, and Ar 2 ga is anthracenylene or phenanthrylene, and R 3 This H compound is excluded.

[0299] Definitions and descriptions provided in relation to the compound of formula (1) in the organic semiconducting layer are also likewise in relation to the compound of the present invention and throughout the entire application text.

[0300] To simplify the synthesis of the present invention, R 1 and R 2 It may be desirable for to be selected identically. That is, R 1 and R 2 C1 to C that are identical 16 It is preferable that it be an alkyl group.

[0301] To adjust the chemical and physical properties, for example, solubility, of the compound of the present invention, R 1 and R 2 Each independently, C1 to C 10 It may be preferable to select from alkyl, preferably C1 to C8 alkyl, more preferably C1 to C6 alkyl, and more preferably C1 to C4 alkyl.

[0302] Ar 1 It is more preferable that this be selected from the group consisting of phenylene, biphenylene, naphthylene, fluorenylene, pyridylene, quinolinylene, and pyrimidinylene.

[0303] Ar 1 This C6 to C 14 It is more desirable to select from arylene.

[0304] It is equally desirable that n is 1.

[0305] It is equally desirable that n is 1 and m is 1.

[0306] Ar 2 ga is unsubstituted, and R 3 It may be more desirable for this to be hydrogen.

[0307] Ar 2 ga is unsubstituted, and R 3 It may be more desirable that this is hydrogen, n is 1, and m is 1.

[0308] In another preferred embodiment, Ar 2 It consists of a single unsubstituted condensed aromatic system or is represented by one of the following chemical formulas:

[0309]

[0310] The condensed aromatic system may be selected from the group consisting of 9,9'-spirobi[fluorene]-2,7-ylene, 9,9'-spirobi[fluorene]-3,6-ylene, spiro[fluorene-9,9'-xanthen]-2,7-ylene, spiro[fluorene-9,9'-xanthen]-3,6-ylene, benzofluorenylene, dibenzofluorenylene, anthracenylene, crisenylene, pyrenylene, phenanthrylene, carbazoylene, benzoacrydinylene, dibenzoacrydinylene, dibenzofuranilene, naphthobenzofuranilene, dinaphthobenzofuranilene, dibenzothiophenylene, naphthobenzothiophenylene, and dinaphthiophenylene.

[0311] Also, Ar 2 It is preferable that α be selected from the group consisting of pyrenyllene, carbazoylene, benzo[c]acridinylene, dibenzo[c,h]acridinylene, dibenzo[a,j]acridinylene, triazenylene, and benzofluorenylene, or from the group of the following chemical formulas (IVa) to (IVp):

[0312]

[0313]

[0314] More preferably, Ar 2 is selected from the group consisting of pyrenylene, benzo[c]acridinylene, dibenzo[c,h]acridinylene and dibenzo[a,j]acridinylene.

[0315] Preferably, Ar 2 Indolyl does not exist in.

[0316] More preferably, Ar 2 is C 14 to C 40 Arrylene, preferably, C 14 to C 22 Selected from Arilen.

[0317] In a preferred embodiment, R 3It is selected from H, phenyl, biphenyl, terphenyl, fluorenyl, naphthyl, phenanthyl, pyrenyl, carbazoyl, dibenzofuranyl or dinaphthofuranyl, preferably from H, phenyl, biphenyl or naphthyl.

[0318] In a preferred embodiment, R 3 When selected from the preferred embodiments mentioned above, the physical properties are particularly suitable for industrial applications.

[0319] Likewise, Ar 1 , Ar 2 and R 3 It is preferable that each of these is independently substituted or unsubstituted with at least one C1 to C6 alkyl group, preferably a C1 to C4 alkyl group.

[0320] Most preferably, Ar 1 , Ar 2 and R 3 It is not substituted.

[0321] In one embodiment, n is 0 and m is 1. A preferred compound of formula (1) according to the present invention is selected from one of the following compounds 1a to 1i:

[0322]

[0323] In another embodiment, n is 1, m is 1, and R 3 H is H. A preferred compound of formula (1) according to the present invention is selected from one of the following compounds 2a to 2gg.

[0324]

[0325]

[0326]

[0327]

[0328] In another embodiment, n is 1, m is 1, and R 3 C1 to C 12 alkyl or C 10to C 20 It is an aryl. A preferred compound of formula (1) according to the present invention is selected from one of the following compounds 3a to 3pp.

[0329]

[0330]

[0331]

[0332]

[0333]

[0334]

[0335]

[0336] In another embodiment, n is 1 and m is 2. A preferred compound of formula (1) according to the present invention is selected from one of the following compounds 4a to 4f.

[0337]

[0338] In another specific example, Ar 2 is selected from particularly bulky substituents. The bulky substituents of the type shown below have a rigid 3D structure that has been identified as particularly desirable. A preferred compound of formula (1) according to the present invention is selected from one of the following compounds 5a to 5c.

[0339]

[0340] In another embodiment, the organic semiconductor layer comprises at least one compound of the following formula (1a):

[0341]

[0342] In the above equation, R 1 and R 2 Each independently, C1 to C 16 Selected from alkyls;

[0343] Ar 1 C6 to C14 Aryllene or C3 to C 12 Heteroarylene, preferably selected from phenylene or biphenylene;

[0344] R 3 is independently H, C1 to C 12 alkyl or C 10 to C 20 Selected from aryls, preferably, R 3 is H;

[0345] n is 1.

[0346] Finally, it is preferable that the compound be selected from one of the following compounds (a) to (q).

[0347]

[0348]

[0349] Surprisingly, the inventors have discovered that an improvement in the performance of an OLED known in the art can be achieved by replacing a diaryl phosphine oxide compound (known in the art) in the electron transport / injection layer with a dialkyl phosphine oxide compound (according to the present invention).

[0350] The beneficial effect is particularly evident in the doped layer as well as in the layer where the dopant is not present, when doped with a lithium organic complex or a zero-valent metal.

[0351] Various dialkyl phosphine oxide compounds were investigated and observed to exhibit particularly beneficial effects. Specifically, the organic semiconducting layer, device, and compound disclosed above were suitable for solving the problem underlying the present invention by characterized by a reduction in the driving voltage of the OLED and / or improvement in external quantum efficiency and / or improvement in lifespan.

[0352] Another particularly preferred embodiment of the present invention relates to an organic light-emitting diode (OLED). In this regard, preferred embodiments are as follows. Brief explanation of the drawing

[0353] These aspects and advantages of the present invention and / or other aspects and advantages will become apparent and more easily understood from the description of the following exemplary embodiments taken in connection with the accompanying drawings. FIG. 1 is a schematic cross-sectional view of an organic light-emitting diode (OLED) according to an exemplary embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an OLED according to an exemplary embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a tandem OLED including a charge generating layer according to an exemplary embodiment of the present invention. Specific details for implementing the invention

[0354] Exemplary embodiments of the present invention will be described in detail below, and examples thereof are illustrated in the accompanying drawings, in which similar reference numbers refer to similar components throughout. Exemplary embodiments are described below with reference to the drawings to explain aspects of the present invention.

[0355] In the present invention, when a first component is referred to as being formed or disposed on a second component "on" it, the first component may be disposed directly on the second component, or one or more other components may be disposed between them. When a first component is referred to as being formed or disposed "directly" on a second component, no other components are disposed between them.

[0356] FIG. 1 is a schematic cross-sectional view of an organic light-emitting diode (OLED) (100) according to an exemplary embodiment of the present invention. The OLED (100) comprises a substrate (110), an anode (120), a hole injection layer (HIL) (130), a hole transport layer (HTL) (140), an emission layer (EML) (150), and an electron transport layer (ETL) (160). An electron transport layer (ETL) (160) comprising or made of a compound of formula (1) is formed directly on the EML (150). An electron injection layer (EIL) (180) is disposed on the electron transport layer (ETL) (160). A cathode (190) is disposed directly on the electron injection layer (EIL) (180).

[0357] Instead of a single electron transport layer (160), an optional electron transport layer stack (ETL) may be used.

[0358] FIG. 2 is a schematic cross-sectional view of an OLED (100) according to another exemplary embodiment of the present invention. FIG. 2 differs from FIG. 1 in that the OLED (100) of FIG. 2 includes an electron blocking layer (EBL) (145) and a hole blocking layer (HBL) (155).

[0359] Referring to FIG. 2, the OLED (100) comprises a substrate (110), an anode (120), a hole injection layer (HIL) (130), a hole transport layer (HTL) (140), an electron blocking layer (EBL) (145), an emission layer (EML) (150), a hole blocking layer (HBL) (155), an electron transport layer (ETL) (160), an electron injection layer (EIL) (180), and a cathode electrode (190). The electron transport layer (ETL) (160) and / or the electron injection layer (EIL) (180) comprises or is composed of a compound of formula (1).

[0360] In the above description, the method of manufacturing an OLED (100) of the present invention starts with a substrate (110), forms an anode (120) thereon, and forms a hole injection layer (130), a hole transport layer (140), an optional electron blocking layer (145), an emission layer (150), an optional hole blocking layer (155), an optional at least one electron transport layer (160), an optional at least one electron injection layer (180), and a cathode (190) on the anode electrode (120) in such order or in another direction.

[0361] FIG. 3 is a schematic cross-sectional view of a tandem OLED (200) according to another exemplary embodiment of the present invention. FIG. 3 differs from FIG. 2 in that the OLED (100) of FIG. 3 further comprises a charge generation layer and a second emission layer.

[0362] Referring to FIG. 3, the OLED (200) comprises a substrate (110), an anode (120), a first hole injection layer (HIL) (130), a first hole transport layer (HTL) (140), a first electron blocking layer (EBL) (145), a first emission layer (EML) (150), a first hole blocking layer (HBL) (155), a first electron transport layer (ETL) (160), an n-type charge generation layer (n-type CGL) (185) that may include a compound of formula (1), a p-type charge generation layer (p-type GCL) (135), a second hole transport layer (HTL) (141), a second electron blocking layer (EBL) (146), a second emission layer (EML) (151), a second hole blocking layer (EBL) (156), a second electron transport layer (ETL) (161), and a second electron It includes an injection layer (EIL) (181) and a cathode (190). The electron transport layer (ETL) (160 and 161) and / or the electron injection layer (EIL) (180) and / or the n-type charge generation layer (n-type CGL) (185) comprises or is made of a compound of formula (1).

[0363] In the above description, the method of manufacturing an OLED (200) of the present invention starts with a substrate (110), forms an anode (120) thereon, and on the anode electrode (120), forms a first hole injection layer (130), a first hole transport layer (140), optional first electron blocking layer (145), a first emission layer (150), optional first hole blocking layer (155), optional at least one first electron transport layer (160), n-type CGL (185), p-type CGL (135), a second hole transport layer (141), optional second electron blocking layer (146), a second emission layer (151), optional second hole blocking layer (156), optional at least one second electron transport layer (161), optional electron injection layer (181), and a cathode (190) in such order or in another direction.

[0364] Although not illustrated in FIGS. 1, 2 and 3, a sealing layer may be additionally formed on the cathode electrode (190) to seal the OLED (100 and 200). Additionally, various other variations may be applied herein.

[0365] Hereinafter, one or more exemplary embodiments of the present invention will be described in detail with reference to the following examples. However, these examples are not intended to limit the purpose and scope of one or more exemplary embodiments of the present invention.

[0366] Examples

[0367] Preparation of the compound of chemical formula (1)

[0368] Dialkylphosphine oxide can be prepared using a known procedure (Method a: Hays, RH, The Journal of Organic Chemistry 1968 33 (10), 3690-3694; method b: W. Voskuil and JF Arens Org. Synth. 1968, 48, 47).

[0369] Method 1

[0370] R 1 =R 2 Synthesis of Dialkylphosphine Oxide

[0371]

[0372] Diethyl phosphonate (0.95 eq) was added to a Grignard solution (3 eq) in cooled THF at a rate that maintained the temperature of the reaction mixture at 20 to 30°C. After stirring for 1 hour at room temperature, the mixture was hydrolyzed by mixing it with an ice-cooled saturated aqueous solution (3 eq) of potassium carbonate. The precipitated magnesium carbonate was removed by filtration and washed several times with ethanol. The combined filtrate was concentrated under vacuum to obtain an unpurified material, which can be further purified by distillation or recrystallization from a suitable solvent.

[0373] Method 2

[0374]

[0375] Grignard solution (2 eq.) in THF or Et2O was added dropwise to a solution of phosphoric trichloride (1 eq) (2 ml / mmol PCl3) in diethyl ether at -40°C. The reaction mixture was stirred at -40°C for 30 minutes, and then allowed to reach room temperature over 3 hours. The reaction was terminated by the addition of water (about 3 eq). The solvent was evaporated under reduced pressure, the oil-containing residue containing some solids was diluted with dichloromethane, filtered, and the solution was dried and evaporated to obtain a clear oil. Subsequently, this oil-containing residue was dissolved in a boiling heptane / ethyl acetate mixture (1:10), the solution was cooled to room temperature, and two liquid phases were formed upon cooling. The upper (heptane) phase was discarded, and the lower phase was concentrated under vacuum to obtain an unrefined product. Further purification can be achieved by recrystallization or vacuum distillation.

[0376]

[0377] Conventional procedure for coupling dialkylphosphine oxide with aryl halide

[0378]

[0379] A Schlenck flask was filled with aryl halide (1 eq) and dialkylphosphine oxide (1 eq.) and sealed with a rubber septum. The atmosphere was replaced with argon, and the starting compounds were dissolved in dioxane anhydride or suspended in a dioxane-THF mixture (1:1 vol.). In a separate vial, a mixture of tris(dibenzylideneacetone)dipalladium (0.005 eq), Xantphos (0.01 eq), and triethylamine (1.17 eq.) was dissolved in dioxane anhydride (75 ml / mmol) at 24°C for 10 minutes. This catalyst solution was added to the mixture of phosphine oxide and aryl halide, and the reaction mixture was stirred at 24°C for 12 to 24 hours.

[0380] Work-up procedure 1 The precipitated solid (trimethylamine salt) was separated by filtration through a sintered glass filter (pore size 4), washed twice with dioxane, and the combined filtrate was dried and evaporated under reduced pressure using a rotary evaporator. The remainder was dissolved in water, and the pH was set to alkaline (approx. 14) using an aqueous potassium hydroxide solution. The resulting yellow, turbid aqueous layer was sequentially extracted with hexane and diethyl ether. The combined organic layer was extracted with an aqueous solution of approximately 0.5 M KOH, the aqueous phases were combined, acidified with hydrochloric acid, and extracted with dichloromethane. The combined extract was washed with a saturated sodium hydrocarbonate solution and brine, and dried on magnesium sulfate. The solvent was removed under reduced pressure, the remainder was ground with hexane, the white crystalline precipitate was collected by vacuum filtration, washed with hexane, and dried.

[0381] Work-up Procedure 2The reaction mixture was diluted with water, and the precipitated material was collected by suction using a sintered glass filter (pore 4), washed with water and methanol, and dried. The unrefined product can be further purified by recrystallization in a suitable solvent. Final purification was achieved by sublimation in a high vacuum.

[0382]

[0383]

[0384] Procedure for Suzuki-Miyaura coupling

[0385] Method a.

[0386] A three-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a magnetic stirring rod was filled with boron acid ester (1 eq) and bromophenyldialkylphosphine oxide (1.5 eq), the flask was sealed with a rubber septum, evacuated, and refilled with argon (twice). Anhydrous THF (10 ml / mmol boron acid ester) was added through the septum using a double-tipped needle. Separately, a catalyst was prepared by suspending bis(dibenzylideneacetone)palladium (0.02 eq) and tri-tert-butylphosphine (0.04 eq) in a small amount of anhydrous THF under argon. The catalyst suspension was added to the reaction mixture through the septum using a syringe. A deoxygenated aqueous solution of tetrabutylammonium hydroxide (about 20 wt%, 2 eq) was added dropwise to the reaction mixture at room temperature (addition time about 30 min). The reaction mixture was stirred at room temperature for 2 hours, the precipitated product was separated by filtration, washed with water, methanol, and hexane, and dried under vacuum at 40°C for 48 hours. The unrefined product was subsequently ground with a hot dichloromethane / hexane mixture (1:1 vol, about 300 ml), filtered at high temperature, and dried under vacuum at 50°C for 1 hour and at 120°C for 1 hour. Final purification was achieved by sublimation under high vacuum.

[0387] Method b.

[0388] Potassium carbonate (51.4 mmol, 3 eq.) was dissolved in approximately 25 ml of deionized water, and the solution was degassed with N2 for 30 minutes. Glim (175 ml) was degassed with N2 for 30 minutes in a 3500 ml three-necked round-bottom flask. Subsequently, the flask was filled with boron acid ester (17.14 mmol, 1 eq.), bromophenyldialkylphosphine oxide (17.99 mmol, 1.05 eq.), and tetrakis(triphenylphosphine)palladium (0) (0.51 mmol, 0.03 eq.) under positive nitrogen pressure. The degassed potassium carbonate solution was added using a syringe, a nitrogen-purged reflux condenser was attached to the flask, and the reaction mixture was heated to 90°C for 12 hours while stirring. The mixture was cooled to room temperature, the precipitate was collected by filtration, washed with water and methanol, and dried at 40°C under vacuum to obtain an unrefined product, which can be further purified by recrystallization or grinding with a suitable solvent. Final purification was achieved by sublimation under high vacuum.

[0389] Method c.

[0390] Potassium carbonate (20 mmol, 2 eq.) was dissolved in about 10 ml of deionized water, and the solution was degassed with N2 for 30 minutes. Dioxane (40 ml) was degassed with N2 for 30 minutes in a 100 ml three-necked round-bottom flask. Subsequently, the flask was filled under positive nitrogen pressure with the corresponding arylboronic acid, aryl bromide, or aryl chloride (10 mmol, 1 eq.), dialkylphosphine oxide derivative (22 mmol, 1.1 eq.), and tetrakis(triphenylphosphine)palladium (0) (0.2 mmol, 0.02 eq.). The degassed potassium carbonate solution was added via syringe, a nitrogen-purged reflux condenser was attached to the flask, and the reaction mixture was heated to 90°C for 12 hours while stirring. The mixture was cooled to room temperature, the precipitate was collected by filtration, washed with water and methanol, and dried at 40°C under vacuum to obtain an unrefined product, which can be further purified by recrystallization or grinding with a suitable solvent. Final purification was achieved by sublimation under high vacuum.

[0391] Method d.

[0392] Potassium carbonate (40 mmol, 2 eq.) was dissolved in approximately 20 ml of deionized water, and the solution was degassed with N2 for 30 minutes. A mixture of toluene and ethanol (15:6 vol., 112 ml) was degassed with N2 for 30 minutes in a 500 ml three-necked round-bottom flask. Subsequently, the flask was filled under positive nitrogen pressure with trifluoromethanesulfonate (20 mmol, 1 eq.), pinacol ester of boronic acid (22 mmol, 1.1 eq.), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.40 mmol, 0.02 eq.). The degassed potassium carbonate solution was added using a syringe, a nitrogen-purged reflux condenser was attached to the flask, and the reaction mixture was heated to 90°C for 12 hours while stirring. The mixture was cooled to room temperature, the precipitate was collected by filtration, washed with water and methanol, and dried at 40°C under vacuum to obtain an unrefined product, which can be further purified by recrystallization or grinding with a suitable solvent. Final purification was achieved by sublimation under high vacuum.

[0393]

[0394]

[0395]

[0396]

[0397]

[0398]

[0399]

[0400] Synthesis of asymmetric dialkylphosphine oxide

[0401]

[0402] General procedure for diethyl phosphonite

[0403] Aryl bromide (0.15 mol) was dissolved in dried tetrahydrofuran (150 mL) under N2, and the solution was cooled to -78°C. nBuLi (0.158 mol, 1.05 eq) was added dropwise to the reaction mixture at this temperature, and the mixture was stirred at -78°C for 1 hour and then for an additional 1 hour. Magnesium bromide ethyl etherate (0.165 mol, 1.1 eq) was added at this temperature, and the mixture was allowed to reach room temperature for 1 hour. Triethyl phosphite (0.1 mol, 0.66 eq) was added all at once at room temperature, and subsequently, the mixture was stirred at 50°C for an additional 1 to 3 hours to complete the reaction. After removing the solvent under reduced pressure, an unpurified material was obtained. Further purification can be achieved by vacuum distillation.

[0404]

[0405] General procedure for phosphinates

[0406] Phosphonite (55.0 mmol) was added to a two-necked round-bottom flask containing alkyl iodide (1.6 mmol, in a pure state or as a solution in THF) at a rate to maintain steady reflux. The reaction was stirred for an additional 18 hours, and subsequently purified by vacuum distillation.

[0407]

[0408] General procedure for phosphine chloride

[0409] Phospinate (35.0 mmol) was dissolved in 1,2-dichloroethane (30 ml), and phosphorus pentachloride (35.1 mmol) was added at a rate maintained at 40°C. After the addition was complete, the reaction was stirred overnight. Volatile substances were removed under reduced pressure to obtain an unpurified substance, which can be further purified by vacuum distillation or recrystallization in a suitable solvent.

[0410]

[0411] General Procedures for Alkyl (Alkyl) Phosphine Oxides

[0412] A solution of phosphine chloride (10 mmol) in anhydrous THF (10 ml) was slowly added to a Grignard solution (10.5 mmol) in THF or diethyl ether. The reaction mixture was stirred under reflux for 1 hour, then cooled in an ice bath and quenched with a saturated aqueous solution of ammonium chloride. The mixture was poured into water, acidified with dilute hydrochloric acid, and extracted with chloroform. The combined extract was washed with a saturated aqueous solution of sodium hydrocarbonate and brine, dried over magnesium sulfate, and concentrated under vacuum to obtain an unpurified product.

[0413] Further purification can be achieved by vacuum distillation or by recrystallization from a suitable solvent.

[0414]

[0415] General procedure for OLEDs having a single emission layer (single OLED)

[0416] General procedure for organic light-emitting diodes of Examples 1 to 11 as well as Comparative Examples 1 to 3, comprising an organic semiconducting layer of Formula (1) as an electron transport layer and / or electron injection layer and / or n-type charge generation layer.

[0417] Lower light-emitting element

[0418] For the bottom light-emitting elements, namely Examples 1 to 11 and Comparative Examples 1 to 3, a 15 Ω / cm² glass substrate having 100 nm ITO (available from Corning Co.) was cut to a size of 50 mm × 50 mm × 0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes, then ultrasonically cleaned with pure water for 5 minutes, and then cleaned again with UV ozone for 30 minutes to prepare a first electrode.

[0419] Subsequently, in the case of Comparative Examples 1 to 3, 92 wt% of (N4,N4"-di(naphthalene-1-yl)-N4,N4"-diphenyl-[1,1':4',1"-terphenyl]-4,4"-diamine) and 8 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile), or in the case of Examples 1 to 8, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine and 8 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) were vacuum deposited on an ITO electrode, A HIL with a thickness of 10 nm was formed. Subsequently, for Comparative Examples 1 to 3 (N4,N4"-di(naphthalene-1-yl)-N4,N4"-diphenyl-[1,1':4',1"-terphenyl]-4,4"-diamine) or for Examples 1 to 8, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on the HIL to form an HTL with a thickness of 130 nm. 97 wt% of ABH113 (Sun Fine Chemicals) as a host and 3 wt% of NUBD370 (Sun Fine Chemicals) as a dopant were deposited on the HTL to form a blue-emitting EML with a thickness of 20 nm.

[0420] A bottom emission device comprising an organic semiconducting layer as an electron transport layer (ETL).

[0421] Subsequently, an organic semiconducting layer comprising the compound of formula (1) was formed by depositing a compound from the first deposition source directly onto the EML, thereby depositing a compound also named as the ETL matrix compound according to Examples 1 to 11 and Comparative Examples 1 to 3.

[0422] In addition, the thickness d (nm) of the ETL can be taken from Table 3.

[0423] An arbitrary electron injection layer was deposited directly on top of the electron transport layer. The composition and thickness of the electron injection layer can be taken from Table 3.

[0424] A bottom light-emitting device comprising an organic semiconducting layer as an electron injection layer (EIL).

[0425] Subsequently, an organic semiconducting layer comprising the compound of formula (1) was formed by depositing a compound also named the EIL matrix compound according to Examples 1 to 11 and Comparative Examples 1 to 3 by directly depositing a matrix compound from a first deposition source and a lithium organic complex or a zero-valent metal dopant from a second deposition source onto the EML.

[0426] The weight percentage of the lithium organic complex for the EIL can be taken from Table 4, thereby adding up to 100% weight% of the matrix compound. This means that the EIL matrix compound is added in a weight percentage amount such that the provided weight percentage of the lithium organic complex for the EIL and the matrix compound of the EIL totals 100% weight% based on the weight of the EIL. Additionally, the thickness d (nm) of the EIL can be taken from Table 4.

[0427] The weight percentage of the zero-valent metal dopant for the EIL can be taken from Table 5, thereby adding up to 100 weight% of the matrix compound. This means that the EIL matrix compound is added in a weight percentage amount such that the provided weight percentage of the zero-valent metal dopant for the EIL and the EIL matrix compound results in a total of 100 weight% based on the weight of the EIL. Additionally, the thickness d (nm) of the EIL can be taken from Table 5.

[0428] 10 cathodes -7Evaporation was performed in an ultra-high vacuum of bar. Accordingly, to produce a uniform cathode having a thickness of 5 to 1000 nm, thermal single simultaneous evaporation of one or several metals was performed at a rate of 0, 1 to 10 nm / s (0.01 to 1 Å / s). A cathode electrode was formed from 100 nm aluminum.

[0429] The OLED stack is protected from ambient conditions by encapsulating the device with a glass slide. As a result, a cavity is formed, which contains a getter material for additional protection.

[0430] The beneficial effects of the compound of formula (1) of the present invention on the performance of the lower light-emitting element can be shown in Tables 3, 4 and 5.

[0431] Upper light-emitting element

[0432] For the upper light-emitting element, an anode electrode was formed on a glass substrate prepared from 100 nm silver by the same method as described above.

[0433] Subsequently, 92 wt% of biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine (CAS 1242056-42-3) and 8 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) were vacuum deposited on an ITO electrode to form a HIL with a thickness of 10 nm. Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine (CAS 1242056-42-3) was vacuum deposited on the HIL to form an HTL with a thickness of 130 nm. As a host, 97 wt% of ABH113 (Sun Fine Chemicals) and 3 wt% of NUBD370 (Sun Fine Chemicals) as a dopant were deposited on an HTL to form a blue-emitting EML with a thickness of 20 nm.

[0434] Upper light-emitting element comprising an organic semiconducting layer of the compound of chemical formula (1)

[0435] An organic semiconducting layer containing a compound of chemical formula (1) was deposited as described for the lower light-emitting element.

[0436] A cathode electrode was formed from a 13 nm magnesium (90 vol%) and silver (10 vol%) alloy, and subsequently from a 60 nm biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine (CAS 1242056-42-3).

[0437] The OLED stack is protected from ambient conditions by encapsulating the device in a glass slide. This forms a cavity containing a getter material for additional protection. To evaluate the performance of the embodiment of the present invention compared to the prior art, current efficiency is measured under ambient conditions (20°C). Current-voltage measurements are performed using a Keithley 2400 sourcemeter and recorded in V. At 10 mA / cm² for the bottom light-emitting element and 15 mA / cm² for the top light-emitting element, a calibrated spectrometer CAS140 from Instrument Systems is used to measure luminance in CIE coordinates and candela units. The device lifetime LT is measured using a Keithley 2400 sourcemeter at ambient conditions (20°C) and 15 mA / cm² and recorded in hours. The device luminance is measured using a calibrated photodiode. The lifetime LT is defined as the time until the device luminance decreases to 97% of its initial value.

[0438] In the bottom light-emitting device, the emission is mainly Lambertian and is quantified as an external quantum efficiency (EQE) percentage. To determine the efficiency EQE in % units, the light output of the device is measured using a calibrated photodiode at 10 mA / cm².

[0439] In the top light-emitting device, emission is forward, non-Lambertian, and also highly dependent on the microcavity. Accordingly, the efficiency EQE will be higher compared to the bottom light-emitting device. To determine the efficiency EQE in % units, the light output of the device is measured using a calibrated photodiode at 15 mA / cm².

[0440] Technical effects of the present invention

[0441] 1. A bottom light-emitting element comprising an organic semiconducting layer comprising a compound of chemical formula (1) in which no dopant is present

[0442] Table 3 shows the performance of a bottom light-emitting device having an organic semiconducting layer without dopants. The organic semiconducting layer functions as an electron transport layer (ETL), and the compound of chemical formula (I) is the ETL matrix compound. The thickness of the ETL is 36 nm.

[0443] To improve electron injection, an electron injection layer is deposited on top of the electron transport layer. In Comparative Example 1 and Examples 1 to 3, LiQ is deposited to a thickness of 1.5 nm. See Table 3.

[0444] In Comparative Example 1, the ETL matrix compound MX 12 is used. In the matrix compound MX 12, three aryl substituents are bonded to the phosphorus atom. The operating voltage is 5.25 V, and the external quantum efficiency EQE is 2.5%. See Table 3. Because the efficiency is too low, the lifetime was not measured.

[0445]

[0446] In Examples 1 and 2, the compound of Formula (1) was tested as an electron transport layer. In Example 1, compound (f) is used as an ETL matrix compound. The operating voltage is reduced to 4.5 V compared to Comparative Example 1. Additionally, the efficiency EQE is improved from 2.5 to 5.1%. The reduction in operating voltage has the advantage that the energy required to operate the OLED can be reduced. Additionally, the increase in efficiency EQE is beneficial for power consumption. The OLED of the present invention exhibits a significant reduction in operating voltage and / or a significant increase in efficiency EQE, which is an improvement that saves electrical energy compared to the prior art. The lifetime is 17 hours. The increase in lifetime means that the device has improved stability over time.

[0447] In Example 2, compound (d) is used as the ETL matrix compound. The operating voltage is further reduced to 4 V, and the efficiency EQE is further increased to 5.7 V. The lifetime is also significantly improved. See Table 3.

[0448] In Example 3, compound (c) is used as the ETL matrix compound. The operating voltage is further reduced to 3.8 V, and the efficiency is improved to 6.4% EQE. The lifespan is also significantly improved to 84 hours.

[0449] The main difference between compounds (c), (d) and (f) and MX 12 is the substitution pattern on the phosphorus atom. In MX 12, three aryl groups are bonded to the phosphorus atom, whereas in compounds (c), (f) and (d), two alkyl and one aryl group are bonded to the phosphorus atom.

[0450] Table 3. Bottom light-emitting device comprising an organic semiconducting layer comprising a compound of chemical formula (1) in which no dopant is present.

[0451]

[0452] 2. A bottom light-emitting element comprising an organic semiconducting layer comprising a compound of chemical formula (1) and an alkali organic complex or an alkali halide.

[0453] Table 4 shows the performance of a bottom light-emitting device having an organic semiconducting layer containing a compound of formula (1) and a lithium organic complex. The organic semiconducting layer functions as an electron injection layer (EIL), and the compound of formula (I) is an EIL matrix compound. The thickness of the EIL is 36 nm.

[0454] In Comparative Example 2, EIL matrix compound MX 12 is used. In matrix compound MX 12, three aryl substituents are bonded to phosphorus atoms. The EIL matrix compound is doped with 50% LiQ, a lithium organic complex. The operating voltage is 4.9 V, and the external quantum efficiency EQE is 5.4%. See Table 4. Because the operating voltage is too high, the lifetime was not measured.

[0455] In Example 4, compound (b) is used as the EIL matrix compound. The matrix compound is doped with the same lithium organic complex at the same concentration as in Comparative Example 2. The operating voltage is reduced from 4.9 to 4.6 V without adversely affecting efficiency. The lifetime was not measured.

[0456] In Example 5, the same matrix compound is used as in Example 4. However, a different lithium organic complex is used. Li-1 is a lithium borate complex. The concentration of the lithium borate complex is 25 wt%. The operating voltage is further reduced to 3.6 V without adversely affecting efficiency. The lifespan is 10 hours.

[0457] In Example 6, compound (c) is used. The same lithium organic complex is used as in Example 5. The operating voltage is further reduced to 3.4 V without adversely affecting efficiency or lifespan. Doping with lithium borate has a particularly beneficial effect on the operating voltage.

[0458] In Example 7, compound (f) is used. The same lithium organic complex is used as in Comparative Example 2 and Example 4. The operating voltage is reduced compared to Comparative Example 2 and Example 4. Additionally, the efficiency is increased to 6.7%, and the lifetime is exceptionally high at 130 hours (Table 4).

[0459] In summary, substantial improvement in the performance of the OLED is achieved through a compound of formula (1) doped with a lithium organic complex.

[0460] Table 4. Bottom light-emitting device comprising an organic semiconducting layer comprising a compound of chemical formula (1) and a lithium organic complex.

[0461]

[0462] 3. A bottom light-emitting element comprising an organic semiconducting layer comprising a compound of chemical formula (1) and a zero-valent metal dopant.

[0463] Table 5 shows the performance of a bottom light-emitting device having an organic semiconducting layer containing a compound of formula (1) and a zero-valent metal dopant. The organic semiconducting layer functions as an electron injection layer (EIL), and the compound of formula (I) is an EIL matrix compound. The thickness of the EIL is 36 nm.

[0464] In Comparative Example 3, EIL matrix compound MX 12 is used. In matrix compound MX 12, three aryl substituents are bonded to phosphorus atoms. The EIL matrix compound is doped with 5 wt% Mg. The operating voltage is 3.8 V, and the external quantum efficiency EQE is 4.8%. See Table 5. The lifetime is 3 hours.

[0465] In Example 8, compound (d) is used as the EIL matrix compound. The matrix compound is doped with Mg at the same concentration as in Comparative Example 3. The operating voltage is reduced from 3.8 to 3.55 V, the efficiency is improved from 4.8 to 5.5%, and the lifetime is significantly improved from 3 to 56 hours.

[0466] In Example 9, compound (c) is used as the EIL matrix compound. The matrix compound is doped with Mg at the same concentration as in Comparative Example 3. The operating voltage is reduced from 3.8 to 3.5 V, the efficiency is improved from 4.8 to 6.1%, and the lifetime is significantly improved from 3 to 33 hours.

[0467] In Example 10, compound (c) is used as the EIL matrix compound. The matrix compound is doped with Yb at the same concentration as in Comparative Example 3. The operating voltage is reduced from 3.8 to 3.7 V, the efficiency is improved from 4.8 to 6.7%, and the lifetime is significantly improved from 3 to 53 hours.

[0468] In Example 11, compound (d) is used as the EIL matrix compound. The operating voltage is 3.7 V. The efficiency is further increased to 6.9% EQE, and the lifetime is very high at 52 hours.

[0469] In summary, beneficial effects are obtained when using a compound of formula (1) doped with a zero-valent metal as an electron injection layer.

[0470] Table 5. Bottom light-emitting device comprising an organic semiconducting layer comprising a compound of chemical formula (1) and a zero-valent metal dopant.

[0471]

[0472] 4. n-type charge generation layer in electron-only devices

[0473] An electronic-only device was fabricated comprising a compound of chemical formula (1) and an organic semiconducting layer comprising a metal dopant as an n-type charge generating layer (n-CGL). Refer to Examples 12 to 17 in Table 6.

[0474] A glass substrate was cut to a size of 50 mm × 50 mm × 0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes, then ultrasonically cleaned with pure water for 5 minutes, and then cleaned again with UV ozone for 30 minutes. Afterwards, an anode electrode was formed on the glass substrate from 100 nm aluminum.

[0475] Subsequently, 90 wt% of biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine and 10 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) were vacuum deposited on the electrode to form an HIL with a thickness of 10 nm.

[0476] Subsequently, an electron transport layer was formed on HIL with a thickness of 30 nm from 2,4-diphenyl-6-(3'-(triphenylene-2-yl)-[1,1'-biphenyl]-3-yl)-1,3,5-triazine (CAS 1638271-85-8).

[0477] Subsequently, an organic semiconducting layer containing 95 wt% of the compound of formula (1) and 5 wt% Yb was deposited on the electron transport layer to form an n-type charge generation layer (n-CGL) with a thickness of 50 nm. See Table 6.

[0478] Subsequently, a p-type charge generating layer (p-CGL) composed of 90 wt% biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine and 10 wt% 2,2',2"-(cyclopropane-1,2,3-triilylidene)tris(2-(p-cyanotetrofluorophenyl)acetonitrile) was vacuum deposited on an n-type charge generating layer to form a p-type charge generating layer having a thickness of 10 nm.

[0479] Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was deposited on p-CGL to form a hole transport layer (HTL) with a thickness of 30 nm.

[0480] Ag was vacuum deposited on the HTL to form a cathode with a thickness of 100 nm.

[0481] Low operating voltage is obtained from electronic-only devices. See Table 6.

[0482] Table 6. An electron-only device having an n-type charge generating layer comprising an organic semiconducting layer comprising a compound of chemical formula (1) and a zero-valent metal dopant.

[0483]

[0484] 5. Tandem OLED Device

[0485] General procedure for OLEDs with two emission layers (tandem OLEDs)

[0486] For the lower light-emitting element, a 15 Ω / cm² glass substrate having 100 nm ITO (available from Corning Co.) was cut to a size of 50 mm × 50 mm × 0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes, then ultrasonically cleaned with pure water for 5 minutes, and then cleaned again with UV ozone for 30 minutes to prepare the first electrode.

[0487] For the upper light-emitting element, the anode electrode was formed from 100 nm silver on glass manufactured by the same method as described above.

[0488] Subsequently, 92 wt% of biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine (CAS 1242056-42-3) and 8 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) were vacuum deposited on an ITO electrode to form an HIL with a thickness of 10 nm. Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on the HIL to form an HTL with a thickness of 135 nm. As a host, 97 wt% of ABH113 (Sun Fine Chemicals) and 3 wt% of NUBD370 (Sun Fine Chemicals) was deposited on an HTL as a dopant to form a blue-emitting EML with a thickness of 25 nm.

[0489] Subsequently, an arbitrary hole blocking layer was deposited directly onto the emission layer.

[0490] Subsequently, an organic semiconducting layer containing a compound of formula (1) was deposited on an emission layer or, if present, a hole blocking layer. When the organic semiconducting layer was an n-type charge generating layer, a p-type charge generating layer composed of 92 wt% biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine and 8 wt% 2,2',2"-(cyclopropane-1,2,3-triilylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) was vacuum deposited on the n-type charge generating layer to form a p-type charge generating layer having a thickness of 10 nm.

[0491] In the case where the organic semiconducting layer is an electron transport layer, an n-type charge generating layer of the compound of formula (X) is deposited on the electron transport layer, and subsequently, a p-type charge generating layer containing the compound of formula (Y) is deposited.

[0492] Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on a p-type charge generation layer to form an HTL with a thickness of 30 nm.

[0493] Subsequently, N3,N3'-di([1,1'-biphenyl]-4-yl)-N3,N3'-dimethyl-[1,1'-biphenyl]-3,3'-diamine (CAS 1639784-29-4) was vacuum deposited on the HTL to form a triplet control layer with a thickness of 15 nm. 90 wt% EL-GHB914S (Samsung SDI) as a host and 10 wt% EL-GD0108S (Samsung SDI) as a phosphorescent green emitter were vacuum deposited on the triplet control layer to form a green emitting EML with a thickness of 30 nm. MX 11 or a compound of formula (1) was vacuum deposited on a green-emitting EML to form an electron transport layer (ETL) with a thickness of 35 nm. LiQ was vacuum deposited on the ETL to form an electron injection layer (EIL) with a thickness of 2 nm. Aluminum was vacuum deposited on the EIL to form a cathode with a thickness of 100 nm.

[0494] A top-emitting tandem OLED device was fabricated comprising a compound of formula (1) and an organic semiconducting layer containing a metal dopant as an n-type charge generating layer (n-CGL). Refer to Comparative Example 4 and Example 17 in Table 7.

[0495] A glass substrate was cut to a size of 50 mm × 50 mm × 0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes, then ultrasonically cleaned with pure water for 5 minutes, and then cleaned again with UV ozone for 30 minutes. An anode electrode was formed on the glass substrate from 100 nm silver.

[0496] Subsequently, 92 wt% of biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine (CAS 1242056-42-3) and 8 wt% of 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) were vacuum deposited on an ITO electrode to form a HIL with a thickness of 10 nm. Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on the HIL to form an HTL with a thickness of 115 nm.

[0497] Subsequently, N,N-bis(4-(dibenzo[b,d]furan-4-yl)phenyl)-[1,1':4',1"-terphenyl]-4-amine (CAS 1198399-61-9) was vacuum deposited on the HTL to form a first electron blocking layer (EBL) with a thickness of 10 nm.

[0498] 97 wt% ABH113 (Sun Fine Chemicals) as a host and 3 wt% BD200 (Sun Fine Chemicals) as a dopant were vacuum deposited on the EBL to form a first blue-emitting EML with a thickness of 20 nm.

[0499] Subsequently, 2,4-diphenyl-6-(3'-(triphenylene-2-yl)-[1,1'-biphenyl]-3-yl)-1,3,5-triazine (CAS 1638271-85-8) was vacuum deposited on the first blue-emitting EML to form a first electron transport layer (ETL) with a thickness of 25 nm.

[0500] Subsequently, an organic semiconducting layer containing 99 volume% of the compound of formula (1) and 1 volume% Yb was vacuum deposited on the first electron transport layer to form an n-CGL with a thickness of 10 nm. Refer to Example 17 in Table 7. In Comparative Example 4, 99 volume% 1,3-bis(9-phenyl-1,10-phenanthroline-2-yl)benzene MX 13 (CAS 721969-94-4) and 1 volume% Yb were vacuum deposited on the first electron transport layer to form an n-CGL with a thickness of 10 nm. Refer to Table 7.

[0501] Subsequently, a p-type charge generating layer composed of 90 wt% biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine and 10 wt% 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) was vacuum deposited on an n-type charge generating layer to form a p-type charge generating layer having a thickness of 10 nm.

[0502] Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on a p-type charge generation layer to form an HTL with a thickness of 50 nm.

[0503] Subsequently, N,N-bis(4-(dibenzo[b,d]furan-4-yl)phenyl)-[1,1':4',1"-terphenyl]-4-amine (CAS 1198399-61-9) was vacuum deposited on the HTL to form a second electron blocking layer (EBL) with a thickness of 10 nm.

[0504] 97 wt% ABH113 (Sun Fine Chemicals) as a host and 3 wt% BD200 (Sun Fine Chemicals) as a dopant were deposited on an HTL to form a second blue-emitting EML with a thickness of 20 nm.

[0505] Subsequently, 2,4-diphenyl-6-(3'-(triphenylene-2-yl)-[1,1'-biphenyl]-3-yl)-1,3,5-triazine (CAS 1638271-85-8) was vacuum deposited on the second blue-emitting EML to form a second electron transport layer (ETL) with a thickness of 25 nm.

[0506] Subsequently, 95 wt% of 3-phenyl-3H-benzo[b]dinaphtho[2,1-d:1',2'-f]phosphephine-3-oxide (CAS 597578-38-6) was vacuum deposited on the second electron transport layer to form an electron injection layer (EIL) with a thickness of 10 nm.

[0507] Ag was vacuum deposited on the EIL to form a cathode with a thickness of 11 nm.

[0508] Subsequently, biphenyl-4-yl(9,9-diphenyl-9H-fluorene-2-yl)-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-amine was vacuum deposited on the cathode to form a capping layer with a thickness of 60 nm.

[0509] The OLED stack is protected from ambient conditions by encapsulating the device into a glass slide. This forms a cavity containing a getter material for additional protection.

[0510] Performance is evaluated as described in the general procedure for a single OLED. Operating voltage, external quantum efficiency and / or lifetime are improved compared to a tandem OLED without an organic semiconducting layer containing a compound of formula (1).

[0511] In Table 7, results for a top-emitting tandem OLED device comprising a matrix compound and an n-type charge generation layer containing a Yb dopant are shown.

[0512] In Comparative Example 4, the n-CGL contains MX13 and Yb dopants. MX12 contains two phenanthroline groups. The operating voltage is 8.3 V, and the external quantum efficiency is 21.6%.

[0513] In Example 17, the n-CGL comprises compound (c) and a Yb dopant. The operating voltage is reduced to 8 V, and the external quantum efficiency is substantially increased to 25%.

[0514] In summary, a substantial improvement in performance can be achieved when the n-type charge generating layer contains a compound of formula (1).

[0515] Table 7. Top-emitting tandem OLED comprising an n-type charge-generating layer organic semiconducting layer comprising a compound of formula (1) and a zero-valent metal dopant.

[0516]

[0517] From the above detailed description and examples, it will be apparent that modifications and alterations to the compositions and methods of the present invention may be made without departing from the spirit and scope of the invention. Accordingly, all modifications to the present invention without departing from the spirit and scope of the invention are intended to be included within the appended claims.

Claims

Claim 1 An organic semiconductive layer that is an electron transport layer and / or an electron injection layer and / or an n-type charge generation layer, wherein the organic semiconductive layer comprises at least one compound of the following chemical formula (1): In the above equation, R 1 and R 2 is methyl;Ar 1 is selected from phenylene and biphenylene;Ar 2 is anthracenylene; R 3 is independently selected from H, phenyl, biphenyl, terphenyl, fluorenyl, and naphthyl; where, each Ar 1 , Ar 2 and R 3 is unsubstituted; n is 1; and m is 1 or 2. Claim 2 delete Claim 3 delete Claim 4 In claim 1, an organic semiconducting layer selected from one of the following compounds (a) to (e): Claim 5 An organic semiconducting layer according to claim 1, further comprising an alkali organic complex and / or an alkali halide. Claim 6 An organic semiconducting layer according to claim 1, further comprising a zero-valent metal dopant. Claim 7 An organic semiconducting layer according to claim 1, composed of at least one compound of chemical formula (1). Claim 8 An organic electroluminescent device comprising an organic semiconducting layer according to any one of claims 1 and 4 to 7. Claim 9 Compound of the following chemical formula (1): In the above equation, R 1 and R 2 is methyl;Ar 1 is selected from phenylene and biphenylene;Ar 2 is anthracenylene;R 3 is independently selected from H, phenyl, biphenyl, terphenyl, fluorenyl, and naphthyl; Ar 1 , Ar 2 and R 3 is unsubstituted; n is 1; and m is 1 or 2. Claim 10 delete Claim 11 delete Claim 12 In claim 9, a compound selected from one of the following compounds (a) to (e): Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete

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