Organic electroluminescent element and display device comprising same

Abstract

The present invention relates to an organic electroluminescent device and to a display device comprising the same.

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent element and to a display device including the same.

[0002] As a self-luminous device, an organic light-emitting diode (OLED) has a wide viewing angle, excellent contrast, fast response, high brightness, excellent driving voltage characteristics, and color reproduction. A typical OLED includes an anode, a hole transport layer (HTL), a light-emitting 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 of an organic compound and / or an organometallic compound.

[0003] When a voltage is applied between the anode and the cathode, holes injected from the anode electrode move to the EML via the HTL, while electrons injected from the cathode electrode move to the EML via the ETL. The holes and electrons recombine in the EML to generate excitons. Light is emitted when the excitons drop from the excited state to the ground state. The injection and flow of holes and electrons should be balanced so that the OLED having the above structure has excellent efficiency.

[0004] In addition, it is known in the art that an OLED includes two or more light-emitting layers between two electrodes. Such an OLED is called a tandem OLED. In such a tandem OLED, a charge generation layer is included between two light-emitting layers, where an n-type charge generation layer provides electrons to the light-emitting layer arranged closer to the anode, while a p-type generation layer provides holes to the light-emitting layer arranged near the cathode. Various materials for preparing such a charge generation layer are known in the art.

[0005] However, there is still a need to improve the performance of organic electroluminescent devices or materials included therein, and in particular, there is a need to improve the performance of (tandem) organic light-emitting diodes including a charge generation layer in terms of operating voltage, efficiency, and / or voltage stability.

[0006] Therefore, an object of the present invention is to provide an organic electroluminescent device that overcomes the disadvantages of the prior art, and in particular, to provide an organic electroluminescent device having a reduced operating voltage and / or improved efficiency and / or improved voltage stability. Summary of the Invention

[0007] The above object is achieved by an organic electroluminescent device (OLED, organic light-emitting diode) including an anode, a cathode, a first electron transport layer, a first light-emitting layer, and a charge generation layer;

[0008] wherein

[0009] - the first light-emitting layer, the first electron transport layer, and the charge generation layer are arranged between the anode and the cathode;

[0010] - The charge generation layer includes an n-type sublayer;

[0011] - The first electron transport layer is in direct contact with the n-type sublayer;

[0012] - The first electron transport layer is disposed between the first light-emitting layer and the n-type sublayer;

[0013] - The first electron transport layer is composed of a first electron transport compound, and the first electron transport compound contains a functional group of formula (1)

[0014]

[0015] and a structural moiety selected from C6 to C 60 arylene and C2 to C 60 heteroarylene,

[0016] wherein

[0017] - X is selected from O, S or Se;

[0018] - R 1 and R 2 are independently selected from substituted or unsubstituted C1 to C 16 alkyl, wherein the substituent of the substituted C1 to C 16 alkyl is selected from C6 to C 18 aryl or C2 to C 12 heteroaryl;

[0019] The wavy line represents the covalent bond by which the P atom of the functional group (1) is connected to the rest of the first electron transport compound;

[0020] - The n-type sublayer contains a second electron transport compound and a metal;

[0021] - wherein the second electron transport compound contains at least two N atoms; and

[0022] - The metal is selected from alkaline earth metals and rare earth metals.

[0023] The object is further achieved by a display device including the organic electroluminescent device.

[0024] The object is further achieved by a compound having a formula selected from E7 and E8

[0025]

[0026] Organic electroluminescent device

[0027] The organic electroluminescent device (organic light-emitting device, OLED) according to the present invention includes an anode, a cathode, a first electron transport layer, a first light-emitting layer, and a charge generation layer. For the purposes of the present disclosure, the mention of "a" or "one" of each layer only means that the organic light-emitting device includes at least this layer, that is, at least one layer of each layer. The existence of other layers of the same type is not excluded. If not explicitly mentioned otherwise, the same applies to the other possible layers of the organic electroluminescent device mentioned herein. Other layers and possible layer arrangements are described in detail below.

[0028] First electron transport layer

[0029] The first electron transport layer is composed of a first electron transport compound, that is, it contains only the first electron transport compound or a mixture of two or more first electron transport compounds (compounds that meet the definition of the first electron transport compound according to the present disclosure), but does not contain any other compounds or materials.

[0030] The first electron transport layer may be composed of two different first electron transport compounds as defined herein.

[0031] In particular, the first electron transport layer does not contain an electrical dopant, and in particular may not contain LiQ. In this regard, "does not contain" means that the corresponding compound (electrical dopant) is only contained in the corresponding layer and cannot be avoided by standard purification methods and common technical means during the preparation of the corresponding layer. In this regard, the electrical dopant is particularly but not limited to an electrical n-type dopant. The electrical n-type dopant may be selected from: metals, or alkali metals; metal salts, or alkaline earth metal salts and / or rare earth metal salts; or organic alkali metal complexes, or alkali metal complexes, or LiF, LiCl, LiBr, LiI, LiQ, metal borates; or mixtures thereof. In particular, the first electron transport layer and the second electron transport layer may not contain an electrical n-type dopant. The electrical n-type dopant may be a metal salt containing at least one metal cation and at least one anion. The metal cation of the metal salt may be selected from alkali metals, alkaline earth metals, and rare earth metals, or from Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba; or from Li, Mg, Ca, and Sr. The anion of the metal salt may be selected from quinolinide, phosphine oxide phenolate, and borate.

[0032] In this regard, the electrical n-type dopants are in particular but not limited to: elemental metals, or electropositive metals selected from alkali metals, alkaline earth metals, rare earth metals and transition metals; metal salts, or alkali metal salts, alkaline earth metal salts and / or rare earth metal salts; or metal complexes, or alkali metal complexes, alkaline earth metal complexes, transition metal complexes and / or rare earth metal complexes. Examples of n-type doped metal salts can be LiF, LiCl, LiBr, LiI, metal borates, metal quinolinates or mixtures thereof. Other examples of electrical n-type dopants are strong chemical reducing agents. The characteristics of such "redox" n-type dopants can generally lie in that the highest occupied molecular orbital (HOMO) energy level is comparable to the lowest unoccupied molecular orbital energy level of the corresponding electron transport matrix (about -3.0 eV or lower in typical OLED transport materials). It should be understood that the term "about -3.0 eV or lower" means a value that is not as negative as -3.0 eV, such as -2.8 eV, -2.5 eV, -2.3 eV, -2.1 eV or a value that is not as negative as -2.0 eV.

[0033] The electrical n-type dopant can be an organic compound as disclosed in EP 1837926 A1, WO 07107306 A1 or WO 07107356 A1.

[0034] The first electron transport layer is in direct contact with the n-type sublayer.

[0035] First electron transport compound

[0036] The first electron transport compound contains (at least one) functional group of formula (1)

[0037]

[0038] and a structural moiety selected from C6 to C 60 heteroarylene and C2 to C 60 arylene.

[0039] The wavy line represents the covalent bond by which the P atom of the functional group (1) is connected to the remainder of the first electron transport compound. For example, if the first electron transport compound consists of one functional group of formula (1) and one structural moiety selected from C6 to C 60 heteroarylene and C2 to C 60 arylene, then the direct bond represented by is formed between the functional group of formula (1) and the said structural moiety.

[0040] X is selected from O, S or Se. X can be selected from O or S. X can be O.

[0041] R 1 and R 2Independently selected from substituted or unsubstituted C1 to C 16 alkyl. That is, the PO moiety (via P) is directly attached to two sp 3 hybridized C atoms. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C 14 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C 12 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C 10 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C8 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C6 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C5 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C4 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C3 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 to C2 alkyl. R 1 and R 2 can independently be selected from substituted or unsubstituted C1 alkyl (methyl).

[0042] One or more substituents of the substituted alkyl are selected from C6 to C 18 aryl or C2 to C 12 heteroaryl. One or more substituents of the substituted alkyl can be selected from C6 to C 12 aryl or C2 to C 11 heteroaryl. One or more substituents of the substituted alkyl can be selected from C6 to C 19 aryl or C2 to C9 heteroaryl. One or more substituents of the substituted alkyl can be selected from C6 aryl or C2 to C 12 heteroaryl.

[0043] R 1 and R 2 are independently selected from unsubstituted C1 to C 16 alkyl. R 1 and R 2 can independently be selected from unsubstituted C1 to C 14 alkyl. R1 and R 2 may be independently selected from unsubstituted C1 to C 12 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C 10 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C8 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C6 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C5 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C4 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C3 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C2 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 alkyl.

[0044] The first electron transport compound comprises a structural moiety selected from C6 to C 60 aryl or C2 to C 60 heteroaryl. The structural moiety may be selected from C 12 to C 54 aryl or C8 to C 54 heteroaryl. The structural moiety may be selected from C 18 to C 54 aryl or C 14 to C 54 heteroaryl. The structural moiety may be selected from C 24 to C 54 aryl or C 20 to C 54 heteroaryl. The structural moiety may be selected from C 30 to C 54 aryl or C 26 to C 54 heteroaryl.

[0045] The structural moiety of the first electron transport compound selected from C6 to C 60 aryl or C2 to C 60 heteroaryl may contain 6 to 10 aromatic and / or heteroaromatic 6-membered rings. The structural moiety of the first electron transport compound selected from C6 to C 60 aryl or C2 to C 60The structural moiety of the heteroaryl may contain 6 to 9 aromatic and / or heteroaromatic 6-membered rings. The first electron transport compound is selected from C6 to C 60 aryl or C2 to C 60 The structural moiety of the heteroaryl may contain 7 or 8 aromatic and / or heteroaromatic 6-membered rings.

[0046] The first electron transport compound is selected from C6 to C 60 aryl or C2 to C 60 The structural moiety of the heteroaryl may contain at least two fused aromatic and / or heteroaromatic 6-membered rings. The first electron transport compound is selected from C6 to C 60 aryl or C2 to C 60 The structural moiety of the heteroaryl may contain at least one structural moiety composed of two or three fused aromatic and / or heteroaromatic 6-membered rings. The first electron transport compound is selected from C6 to C 60 aryl or C2 to C 60 The structural moiety of the heteroaryl may contain at least one structural moiety composed of two or three fused aromatic 6-membered rings.

[0047] The first electron transport compound may have the formula (2)

[0048]

[0049] In formula (2), X is selected from O, S or Se. X may be selected from O or S. X may be O.

[0050] In formula (2), R 1 and R 2 are independently selected from substituted or unsubstituted C1 to C 16 alkyl. That is, the PO moiety (via P) is directly connected to two sp 3 hybridized C atoms. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C 14 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C 12 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C 10 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C8 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C6 alkyl. R 1 and R 2may be independently selected from substituted or unsubstituted C1 to C5 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C4 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C3 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 to C2 alkyl. R 1 and R 2 may be independently selected from substituted or unsubstituted C1 alkyl.

[0051] One or more substituents of the substituted alkyl are selected from C6 to C 18 aryl or C2 to C 12 heteroaryl. One or more substituents of the substituted alkyl may be selected from C6 to C 12 aryl or C2 to C 11 heteroaryl. One or more substituents of the substituted alkyl may be selected from C6 to C 19 aryl or C2 to C9 heteroaryl. One or more substituents of the substituted alkyl may be selected from C6 aryl or C2 to C 12 heteroaryl.

[0052] R 1 and R 2 may be independently selected from unsubstituted C1 to C 16 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C 14 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C 12 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C 10 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C8 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C6 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C5 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C4 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 to C3 alkyl. R 1 and R 2may be independently selected from unsubstituted C1 to C2 alkyl. R 1 and R 2 may be independently selected from unsubstituted C1 alkyl.

[0053] n is 1 or 2.

[0054] Ar 1 is selected from unsubstituted or substituted C6 to C 60 aryl and C2 to C 60 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 60 aryl and C2 to C 60 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 54 aryl and C2 to C 54 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 48 aryl and C2 to C 48 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 42 aryl and C2 to C 42 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 36 aryl and C2 to C 36 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 30 aryl and C2 to C 30 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C6 to C 24 aryl and C2 to C 24 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C 10 to C 24 aryl and C7 to C 24 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C 10 to C 18 aryl and C9 to C 20 heteroaryl. Ar 1 may be selected from unsubstituted or substituted C 10 to C 14 aryl and C9 to C 18 heteroaryl. Ar 1 may be independently selected from naphthyl and pyrimidine.

[0055] Ar 1 、that is, substituted C2 to C 60 heteroaryl, C6 to C60 One or more substituents of the aryl group are each independently selected from D, C1 to C 12 alkyl, C1 to C 12 alkoxy, CN, OH, halogen, C6 to C 32 aryl or C2 to C 25 heteroaryl, preferably selected from H and C1 to C4 alkyl.

[0056] Ar 1 may be selected from the following structures

[0057] and

[0058] wherein Ar 1 is bonded to L at *1 1 bond.

[0059] L 1 may be a substituted or unsubstituted C6 to C 36 arylene. L 1 may be a substituted or unsubstituted C 10 to C 30 arylene. L 1 may be a substituted or unsubstituted C 12 to C 26 arylene.

[0060] One or more substituents of the substituted C6 to C 36 arylene are independently selected from D, C1 to C 12 alkyl, C1 to C 12 alkoxy, CN, OH, halogen, C6 to C 32 aryl or C2 to C 25 heteroaryl, preferably selected from D and C1 to C4 alkyl.

[0061] L 1 may be selected from biphenyl-diyl, terphenyl-diyl or the like, wherein in the like, one or more phenyl rings of the biphenyl-diyl and terphenyl-diyl are each replaced by a ring system (i.e., a ring system such as naphthylene or anthrylene) containing two or more (such as two or three) fused benzene rings.

[0062] L 1 may be selected from the following structures

[0063]

[0064] wherein L 1 is bonded to Ar at *1 1 bond and L 1 is bonded to L at *2 2 bond. L2 Selected from a single bond or a C1 to C6 alkyl group. L 2 May be a single bond.

[0065] The compound of formula (1) or (2) may be selected from E1 to E8:

[0066]

[0067]

[0068] The first electron transport compound may be different from the second electron transport compound.

[0069] The first electron transport layer may consist of only one first electron transport compound, i.e., molecules having the same structural formula.

[0070] Charge generation layer

[0071] The most important use of the charge generation layer is in tandem OLEDs. In this case, the charge generation layer is disposed between the first light-emitting layer and the second light-emitting layer. The charge generation layer includes an n-type sublayer (n-type doped sublayer; n-type charge generation layer). The charge generation layer may also include a p-type doped sublayer (p-type sublayer). The n-type sublayer provides electrons to the light-emitting layer disposed closer to the anode, while the p-type sublayer provides holes to the light-emitting layer disposed near the cathode.

[0072] The n-type sublayer contains a metal. The metal is selected from alkaline earth metals and rare earth metals, such as Mg, Ca, Sr, Ba, Eu, and Yb, especially Mg, Ca, Sr, and Yb, particularly Yb, or a mixture of two or more of the above. The metal contained in the n-type doped sublayer is an n-type dopant, i.e., an electrical dopant that improves the transport of electrons in the sublayer. Preferably, the metal is a rare earth metal, most preferably Yb. The metal exists in the n-type sublayer in its (substantially) elemental form, i.e., the oxidation number is 0 (zero) and it does not exist in the form of a metal salt or a metal complex.

[0073] The n-type doped sublayer further contains a second electron transport compound that can be considered an n-type matrix material. The second electron transport compound may be the main material in the n-type doped sublayer, i.e., the content relative to the total weight of the n-type sublayer may be selected from at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%.

[0074] The n-type sublayer may contain only one type of second electron transport compound. If the n-type sublayer may contain only one type of second electron transport compound, then the second electron transport compound may contain only one non-fused pyridine moiety.

[0075] The n-type sublayer is in direct contact with the first electron transport layer.

[0076] Second electron transport compound

[0077] The second electron transport compound contains at least two N atoms.

[0078] According to one embodiment, the second electron transport compound is selected from formula (xxa) or formula (xxb):

[0079]

[0080] wherein Ar I is a substituted or unsubstituted C3 to C containing at least one nitrogen atom, and preferably at least two nitrogen atoms in the case of xxa 40 heteroaromatic ring system,

[0081] wherein Ar II is a substituted or unsubstituted C3 to C 40 heteroaromatic ring system,

[0082] wherein Ar I and Ar II the substituents on are the same or different each time they appear and are: D, a monovalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms which can be substituted by one or more radicals R a substituted;

[0083] wherein Ar Ia , Ar Ib , Ar Ic , Ar IIa and Ar IIb are the same or different each time they appear and are: H, D, a monovalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms which can be substituted by one or more radicals R a substituted;

[0084] wherein at least one of Ar Ia , Ar Ib , Ar Ic in formula (xxa) and at least one of Ar Ia , Ar Ib , Ar IIa and Ar IIb in the case of formula (II) are independently selected from a monovalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms which can be substituted by one or more radicals R a substituted;

[0085] wherein Ar L is optionally substituted by one or more radicals Ra A divalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms and being substituted;

[0086] wherein R a is, each time it appears, the same or different and is: H, D, F, Cl, Br, I, CHO, N(R b )2, N(Ar 1s )2, B(Ar 1s )2, C(=O)Ar 1s , P(=Y)(R c )2, S(=O)Ar 1s , S(=O)2Ar 1s , CR b =CR b Ar 1s , CN, NO2, Si(R b )3, B(OR b )2, B(R b )2, B(N(R b )2)2, OSO2R b , a substituted or unsubstituted straight-chain C1 to C 20 alkyl, a substituted or unsubstituted straight-chain C1 to C 20 alkenyl, a substituted or unsubstituted straight-chain C1 to C 20 alkynyl, a substituted or unsubstituted straight-chain C1 to C 20 alkoxy, a substituted or unsubstituted straight-chain C1 to C 20 thioalkoxy, a substituted or unsubstituted branched C3 to C 20 alkyl, a substituted or unsubstituted branched C3 to C 20 alkenyl, a substituted or unsubstituted branched C3 to C 20 alkynyl, a substituted or unsubstituted branched C3 to C 20 alkoxy or a substituted or unsubstituted C3 to C 20 branched thioalkoxy, a substituted or unsubstituted cyclic C3 to C 40 alkyl, a substituted or unsubstituted cyclic C3 to C 40 alkenyl, a substituted or unsubstituted cyclic C3 to C 40 alkynyl, a substituted or unsubstituted cyclic C3 to C 40 alkoxy or a substituted or unsubstituted cyclic C3 to C 40 thioalkoxy; a substituted or unsubstituted heterocyclic C3 to C 40 alkyl, a substituted or unsubstituted heterocyclic C3 to C 40 alkenyl, a substituted or unsubstituted heterocyclic C3 to C 40 alkynyl, a substituted or unsubstituted heterocyclic C3 to C 40 alkoxy or a substituted or unsubstituted heterocyclic C3 to C40 Thioalkoxy; wherein if there is one or more substituents, the one or more substituents are independently selected from R b , wherein one or more non-adjacent CH2 groups are optionally replaced by R b C═CR b , C≡C, Si(R b )2, Ge(R b )2, Sn(R b )2, C═O, C═S, C═Se, C═NR b , P(═O)(R b ), SO, SO2, NR b , O, S or CONR b , and wherein one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN or NO2, or in each case may be substituted by one or more radicals R b substituted aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, or optionally substituted aryloxy or heteroaryloxy groups having 5 to 60 aromatic ring atoms by one or more radicals R b , or combinations of these systems; two or more adjacent substituents R a optionally form aliphatic or aromatic ring systems, monocyclic or polycyclic, with each other herein;

[0087] wherein Ar 1s is the same or different in each occurrence and is: an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms optionally substituted by one or more radicals R b ; two radicals Ar 1s bonded to the same nitrogen, phosphorus or boron atom may also be linked to each other herein by a single bond or a bridging group selected from B(R b ), C(R b )2, Si(R b )2, C═O, C═NR b , C═C(R b )2, O, S, S═O, SO2, N(R b ), P(R b ) and P(═Y)R c ;

[0088] wherein R b is the same or different in each occurrence and is: H, D or a C1 to C 20 aliphatic hydrocarbon group, a C1 to C 20 aryl and / or a C1 to C 20 heteroaryl, wherein, additionally, H atoms are optionally replaced by D or F; two or more adjacent substituents R bA single-ring or poly-ring aliphatic or aromatic ring system may also be formed with each other herein;

[0089] wherein Y is selected from O, S or Se, preferably O, and R c is independently selected from C6 to C 12 aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or fully fluorinated C1 to C6 alkyl, partially or fully fluorinated C1 to C6 alkoxy, partially or fully deuterated C1 to C6 alkyl, partially or fully deuterated C1 to C6 alkoxy.

[0090] For the purposes of the present invention, an aromatic or heteroaromatic ring system is intended to be taken to mean not necessarily containing only one aryl or one heteroaryl group or only aryl or heteroaryl groups but rather in which a plurality of aryl or heteroaryl groups may also be interrupted by short non-aromatic units such as, for example, sp 3 hybridized C, N or O atoms (preferably less than 10% of the non-H atoms). Thus, for example, for the purposes of the present invention, systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, benzophenone, etc. are also intended to be taken to mean aromatic ring systems. Similarly, an aromatic or heteroaromatic ring system is taken to mean a system in which a plurality of aryl or heteroaryl groups are connected to each other by single bonds, such as biphenyl, terphenyl or bipyridine.

[0091] According to one embodiment, Ar I is selected from pyrazine, pyridine, pyrimidine or triazine, phenanthroline.

[0092] According to one embodiment, Ar II is selected from pyrazine, pyridine, pyrimidine or triazine, phenanthroline.

[0093] According to one embodiment, Ar in formula (xxa) or (xxxa) I is selected from pyrazine, pyridine, pyrimidine, triazine, phenanthroline; or Ar in formula (xxa) or (xxxa) I and Ar in formula (xxb) or (xxxb) II are independently selected from pyrazine, pyridine, pyrimidine, triazine or phenanthroline from each other.

[0094] According to one embodiment, the compound containing at least one nitrogen atom in the six-membered aromatic ring in the electron transport layer is selected from formula (xxxa) or formula (xxxb):

[0095]

[0096] wherein

[0097] Z Ia is selected from N or CH,

[0098] Z Ib is selected from N or CH,

[0099] Z Ic is selected from N or CH,

[0100] Z IIa is selected from N or CH,

[0101] Z IIb is selected from N or CH, and

[0102] Z IIc is selected from N or CH,

[0103] wherein in formula (XXxa) Z Ia 、Z Ib and Z Ic at least one of which is selected from N,

[0104] wherein in formula (XXxb) Z Ia 、Z Ib 、Z Ic 、Z IIa 、Z IIb and Z IIc at least one of which is selected from N,

[0105] wherein Ar Ia 、Ar Ib 、Ar Ic 、Ar IIa and Ar IIb is the same or different each time it appears as: a monovalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms which may in each case be substituted by one or more radicals R a ;

[0106] wherein Ar L is an optionally substituted divalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms by one or more radicals R a ;

[0107] wherein R a is the same or different each time it appears as: H, D, F, Cl, Br, I, CHO, N(R b )2, N(Ar 1s )2, B(Ar 1s )2, C(=O)Ar 1s 、P(=Y)(R c )2, S(=O)Ar 1s 、S(=O)2Ar 1s 、CR b =CR b Ar 1s, CN, NO2, Si(R b )3, B(OR b )2, B(R b )2, B(N(R b )2)2, OSO2R b , substituted or unsubstituted straight-chain C1 to C 20 alkyl, substituted or unsubstituted straight-chain C1 to C 20 alkenyl, substituted or unsubstituted straight-chain C1 to C 20 alkynyl, substituted or unsubstituted straight-chain C1 to C 20 alkoxy, substituted or unsubstituted straight-chain C1 to C 20 thioalkoxy, substituted or unsubstituted branched C3 to C 20 alkyl, substituted or unsubstituted branched C3 to C 20 alkenyl, substituted or unsubstituted branched C3 to C 20 alkynyl, substituted or unsubstituted branched C3 to C 20 alkoxy or substituted or unsubstituted branched C3 to C 20 thioalkoxy, substituted or unsubstituted cyclic C3 to C 40 alkyl, substituted or unsubstituted cyclic C3 to C 40 alkenyl, substituted or unsubstituted cyclic C3 to C 40 alkynyl, substituted or unsubstituted cyclic C3 to C 40 alkoxy or substituted or unsubstituted cyclic C3 to C 40 thioalkoxy; substituted or unsubstituted heterocyclic C3 to C 40 alkyl, substituted or unsubstituted heterocyclic C3 to C 40 alkenyl, substituted or unsubstituted heterocyclic C3 to C 40 alkynyl, substituted or unsubstituted heterocyclic C3 to C 40 alkoxy or substituted or unsubstituted heterocyclic C3 to C 40 thioalkoxy;

[0108] wherein if there is one or more substituents, the one or more substituents are selected from R b , wherein one or more non-adjacent CH2 groups are optionally replaced by R b C=CR b , C≡C, Si(R b )2, Ge(R b )2, Sn(R b )2, C=O, C=S, C=Se, C=NR b , P(=O)(R b ), SO, SO2, NR b , O, S or CONR bsubstituted, and one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN or NO2, or in each case may be replaced by one or more radicals R b substituted aromatic or heteroaromatic ring systems having 5 to 60 aromatic ring atoms, or optionally substituted by one or more radicals R b substituted aryloxy or heteroaryloxy groups having 5 to 60 aromatic ring atoms, or combinations of these systems; two or more adjacent substituents R a here optionally form an aliphatic or aromatic ring system of a single ring or multiple rings with each other;

[0109] wherein Ar 1s is the same or different each time it appears as: optionally substituted by one or more radicals R b substituted aromatic or heteroaromatic ring systems having 5 to 30 aromatic ring atoms; two radicals Ar bonded to the same nitrogen, phosphorus or boron atom 1s here may also be connected to each other by a single bond or a bridging group selected from B(R b )、C(R b )2、Si(R b )2、C=O、C=NR b 、C=C(R b )2、O、S、S=O、SO2、N(R b )、P(R b ) and P(=Y)R c ;

[0110] wherein R b is the same or different each time it appears as: H, D or C1 to C 20 aliphatic hydrocarbon group, C1 to C 20 aryl and / or C1 to C 20 heteroaryl, wherein, in addition, the H atom is optionally replaced by D or F; two or more adjacent substituents R b here may also form an aliphatic or aromatic ring system of a single ring or multiple rings with each other;

[0111] wherein Y is selected from O, S or Se, preferably O, and R c is independently selected from C6 to C 12 aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or fully fluorinated C1 to C6 alkyl, partially or fully fluorinated C1 to C6 alkoxy, partially or fully deuterated C1 to C6 alkyl, partially or fully deuterated C1 to C6 alkoxy.

[0112] For the purposes of the present invention, an aromatic or heteroaromatic ring system is intended to be taken as meaning that it does not necessarily contain only aryl or heteroaryl groups but that multiple aryl or heteroaryl groups therein may also be interrupted by short non-aromatic units such as, for example, sp 3 hybridized C, N or O atoms (preferably less than 10% of the non-H atoms). Thus, for example, for the purposes of the present invention, systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, benzophenone, etc. are also intended to be taken as meaning an aromatic ring system. Similarly, an aromatic or heteroaromatic ring system is taken as meaning a system in which multiple aryl or heteroaryl groups are connected to one another by single bonds, such as biphenyl, terphenyl or bipyridine.

[0113] The second electron transport compound may comprise a moiety consisting of 2 to 6 fused aromatic rings. The second electron transport compound may comprise a moiety consisting of 2 to 5 fused aromatic rings. The second electron transport compound may comprise a moiety consisting of 2 to 4 fused aromatic rings. The second electron transport compound may comprise a moiety consisting of 2 or 3 fused aromatic rings.

[0114] The second electron transport compound may comprise an aromatic hydrocarbon moiety consisting of 2 to 6 fused aromatic rings. The second electron transport compound may comprise an aromatic hydrocarbon moiety consisting of 2 to 5 fused aromatic rings. The second electron transport compound may comprise an aromatic hydrocarbon moiety consisting of 2 to 4 fused aromatic rings. The second electron transport compound may comprise an aromatic hydrocarbon moiety consisting of 2 or 3 fused aromatic rings. The aromatic hydrocarbon moiety is selected from naphthalene, anthracene, phenanthrene and pyrene, preferably anthracene.

[0115] The second electron transport compound may comprise 7 to 10 aromatic 5- or 6-membered rings. The second electron transport compound may comprise 8 aromatic 5- or 6-membered rings.

[0116] The second electron transport compound may have a molecular weight ranging from 400 g / mol to 1800 g / mol.

[0117] The second electron transport compound may comprise a heteroaromatic hydrocarbon moiety selected from azine, diazine, triazine, oxazole, dioxazole, quinoline, isoquinoline, phenanthridine, acridine, phenanthroline.

[0118] The second electron transport compound may comprise a heteroaromatic hydrocarbon moiety selected from diazine, dioxazole, benzimidazole, imidazopyridine, phenanthroline, quinazoline, benzoquinazoline and quinoxaline, wherein each heteroaromatic hydrocarbon moiety is unsubstituted or substituted by C6-C 18 aryl or C2-C 12 heteroaryl, wherein C6-C 18 aryl or C2-C 12 heteroaryl may each be independently substituted by one or more groups selected from C1-C4 alkyl.

[0119] The second electron transport compound may be selected from the following compounds F6 to F9.

[0120]

[0121]

[0122] It may be specified that the second electron transport compound does not contain a dialkylphosphine oxide structural moiety.

[0123] It may be specified that, except for pyridyl-imidazopyridine or phenanthroline, the second electron transport compound does not contain another metal chelating structural moiety.

[0124] Second light emitting layer

[0125] The organic electroluminescent device may include a second light-emitting layer. The charge generation layer may be disposed between the first light-emitting layer and the second light-emitting layer. The second light-emitting layer may be disposed closer to the cathode than the first light-emitting layer.

[0126] The first hole blocking layer

[0127] The organic electroluminescent device may further include a first hole blocking layer disposed between the first electron transport layer and the first light-emitting layer.

[0128] Second electron transport layer

[0129] The organic electroluminescent device may further include a second electron transport layer. The second electron transport layer may be disposed between the second light-emitting layer and the cathode. The second electron transport layer contains a second electron transport material. The second light-emitting layer is disposed closer to the cathode than the first light-emitting layer.

[0130] In one embodiment, the second electron transport layer is in direct contact with (sandwiched between) the first electron transport layer and the first light-emitting layer.

[0131] The first electron transport material and the second electron transport material may include the same electron transport matrix compound or a mixture of electron matrix compounds, in particular one or more electron transport matrix compounds as defined above for the first electron transport matrix compound in one or more embodiments and combinations thereof.

[0132] The second electron transport layer may contain an electrical dopant. In this regard, the electrical dopant is particularly but not limited to an electrical n-type dopant. The electrical n-type dopant may be selected from: metals, or alkali metals; metal salts, or alkaline earth metal salts and / or rare earth metal salts; or organic alkali metal complexes, or alkali metal complexes, or LiF, LiCl, LiBr, LiI, LiQ, metal borates; or mixtures thereof. In particular, the first electron transport layer and the second electron transport layer may be free of electrical n-type dopants. The electrical n-type dopant may be a metal salt containing at least one metal cation and at least one anion. The metal cation of the metal salt may be selected from alkali metals, alkaline earth metals and rare earth metals; or selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba, or selected from Li, Mg, Ca and Sr. The anion of the metal salt may be selected from quinolinide, phosphine oxide phenolate and borate. In particular, the electrical dopant may be LiQ.

[0133] In this regard, the electrical n-type dopant is particularly but not limited to: elemental metals, or electropositive metals selected from alkali metals, alkaline earth metals, rare earth metals and transition metals, transition metals; metal salts, or alkali metal salts, alkaline earth metal salts and / or rare earth metal salts; or metal complexes, or alkali metal complexes, alkaline earth metal complexes, transition metal complexes and / or rare earth metal complexes. Examples of n-type doped metal salts may be LiF, LiCl, LiBr, LiI, metal borates, metal quinolinates or mixtures thereof. Other examples of electrical n-type dopants are strong chemical reducing agents. The characteristics of such "redox" n-type dopants generally may lie in that the highest occupied molecular orbital (HOMO) energy level is comparable to the lowest unoccupied molecular orbital energy level of the corresponding electron transport matrix (about -3.0 eV or lower in typical OLED transport materials). It should be understood that the term "about -3.0 eV or lower" means not a value as negative as -3.0 eV, such as -2.8 eV, -2.5 eV, -2.3 eV, -2.1 eV or not a value as negative as -2.0 eV.

[0134] The electrical n-type dopant may be an organic compound as disclosed in EP 1837926 A1, WO 07107306 A1 or WO 07107356 A1.

[0135] The second electron transport layer may contain a first electron transport compound containing the functional group of formula (1) as a matrix material. The second electron transport layer may contain the same first electron transport compound containing the functional group of formula (1) that forms the first electron transport layer as a matrix material.

[0136] Electron injection layer

[0137] The organic light-emitting device may further include an electron injection layer, and the electron injection layer may be disposed between the second electron transport layer and the cathode.

[0138] The second electron transport layer may be in direct contact with the electron injection layer. The second electron transport layer may be in direct contact with the cathode. The electron injection layer may be sandwiched between the second electron transport layer and the cathode in contact.

[0139] The electron injection layer may include a metal, or an alkali metal; a metal salt, or an alkaline earth metal salt and / or a rare earth metal salt; or an organic alkali metal complex, or an alkali metal complex, or LiF, LiCl, LiBr, LiI, LiQ, a metal borate; or a mixture thereof. In particular, the electron injection layer may include Yb.

[0140] The electron injection layer may be composed of a metal, or an alkali metal; a metal salt, or an alkaline earth metal salt and / or a rare earth metal salt; or an organic alkali metal complex, or an alkali metal complex, or LiF, LiCl, LiBr, LiI, LiQ, a metal borate; or a mixture thereof. In particular, the electron injection layer may be composed of Yb.

[0141] Other layers

[0142] According to the present invention, the organic light-emitting device may further include other layers in addition to the layers already mentioned above. Exemplary embodiments of each layer are described below:

[0143] Substrate

[0144] The substrate may be any substrate commonly used in the manufacture of the organic light-emitting device. If light is to be emitted through the substrate, the substrate should be a transparent or translucent material, such as a glass substrate or a transparent plastic substrate. If light is to be emitted through the top surface, the substrate may be a transparent and opaque material, such as a glass substrate, a plastic substrate, a metal substrate or a silicon substrate.

[0145] Anode electrode

[0146] The first electrode or the second electrode may be the anode electrode. The anode electrode may be formed by depositing or sputtering a material for forming the anode electrode. The material for forming the anode electrode may be a high work function material to facilitate hole injection. The anode material may also be selected from low work function materials (i.e., aluminum). The anode electrode may be a transparent electrode or a reflective electrode. Transparent conductive oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), aluminum zinc oxide (AlZO) and zinc oxide (ZnO) may be used to form the anode electrode. The anode electrode may also be formed using a metal, which is usually silver (Ag), gold (Au) or a metal alloy.

[0147] Hole injection layer

[0148] A hole injection layer (HIL) can be formed on the anode electrode by vacuum deposition, spin coating, printing, casting, slot die coating, Langmuir-Blodgett (LB) deposition, etc. When using vacuum deposition to form the HIL, the deposition conditions can vary according to the compound used to form the HIL and the desired HIL structure and thermal properties. However, generally speaking, the conditions for vacuum deposition can include a deposition temperature of 100 °C to 500 °C, a pressure of 10 -8 torr to 10 -3 torr (1 torr is equal to 133.322 Pa), and a deposition rate of 0.1 nm / second to 10 nm / second.

[0149] When using spin coating or printing to form the HIL, the coating conditions can vary according to the compound used to form the HIL and the desired HIL structure and thermal properties. For example, the coating conditions can 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. After coating, the heat treatment removes the solvent.

[0150] The HIL can be formed from any compound commonly used to form the HIL. Examples of compounds that can be used to form the HIL include: phthalocyanine compounds, such as 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).

[0151] In such a case, the HIL can be a layer of a pure p-type dopant or can be selected from hole-transporting matrix compounds doped with a p-type dopant. Typical examples of known redox-doped hole-transporting materials are: copper phthalocyanine (CuPc) with a HOMO level of about -5.2 eV, doped with tetrafluoro-tetracyanoquinodimethane (F4TCNQ) with a LUMO level of about -5.2 eV; zinc phthalocyanine (ZnPc) (HOMO = -5.2 eV) doped with F4TCNQ; α-NPD (N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine) doped with F4TCNQ; α-NPD (PD1) doped with 2,2'-(perfluoronaphthalene-2,6-diyl)dipropanedinitrile; α-NPD (PD2) doped with 2,2',2''-(cyclopropane-1,2,3-triyl)tris(2-(p-cyanotetrafluorophenyl)acetonitrile). The dopant concentration can be selected from 1 wt% to 20 wt%, more preferably from 3 wt% to 10 wt%.

[0152] The thickness of the HIL can range from about 1 nm to about 100 nm, and for example, from about 1 nm to about 25 nm. When the thickness of the HIL is within this range, the HIL can have excellent hole injection characteristics without substantial impairment of the driving voltage.

[0153] Hole transport layer

[0154] A hole transport layer (HTL) can be formed on the HIL by vacuum deposition, spin coating, slot die coating, printing, casting, Langmuir-Blodgett (LB) deposition, etc. When the HTL is formed by vacuum deposition or spin coating, the conditions for deposition and coating can be similar to those for forming the HIL. However, the conditions for vacuum or solution deposition can vary depending on the compound used to form the HTL.

[0155] The HTL can be formed by any compound commonly used to form the HTL. Compounds that can be suitably used are, for example, disclosed in Yasuhiko Shirota and Hiroshi Kageyama, Chem. Rev. 2007, 107, 953 - 1010, and are incorporated herein by reference. Examples of compounds that can be used to form the HTL are: carbazole derivatives such as N-phenylcarbazole or polyvinylcarbazole; benzidine derivatives such as N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD) or N,N'-di(naphthalen-1-yl)-N,N'-diphenylbenzidine (α-NPD); and triphenylamine compounds such as 4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA). Among these compounds, TCTA can transport holes and inhibit exciton diffusion into the EML.

[0156] The thickness of the HTL can be in the range of about 5 nm to about 250 nm, preferably about 10 nm to about 200 nm, more preferably about 20 nm to about 190 nm, more preferably about 40 nm to about 180 nm, more preferably about 60 nm to about 170 nm, more preferably about 80 nm to about 160 nm, more preferably about 100 nm to about 160 nm, and more preferably about 120 nm to about 140 nm. The preferred thickness of the HTL can be 170 nm to 200 nm.

[0157] When the thickness of the HTL is within this range, the HTL can have excellent hole transport characteristics without substantial impairment of the driving voltage.

[0158] Electron blocking layer

[0159] The function of the electron blocking layer (EBL) is to prevent electrons from transferring from the light-emitting layer to the hole transport layer, thereby confining the electrons to the light-emitting layer. Thereby, the efficiency, operating voltage, and / or lifetime are improved. Generally, the electron blocking layer contains a triarylamine compound. The triarylamine compound can have a LUMO level closer to the vacuum level than the LUMO level of the hole transport layer. Compared with the HOMO level of the hole transport layer, the electron blocking layer can have a HOMO level farther from the vacuum level. The thickness of the electron blocking layer can be selected between 2 nm and 20 nm.

[0160] The electron blocking layer can contain the following compound of formula (Z).

[0161]

[0162] In formula (Z), CY1 and CY2 are the same or different from each other and each independently represents a benzene ring or a naphthalene ring, Ar1 to Ar3 are the same or different from each other and each independently selected from: 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, Ar4 is selected from a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted terphenylene group, and a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms, and L is a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.

[0163] If the electron blocking layer has a high triplet energy level, it can also be described as a triplet control layer.

[0164] If a phosphorescent green or blue light-emitting layer is used, the function of the triplet control layer is to reduce the quenching of triplets. Thus, higher luminous efficiency from the phosphorescent light-emitting layer can be achieved. The triplet control layer is selected from triarylamine compounds having a triplet energy level higher than that of the phosphorescent emitter in the adjacent light-emitting layer. Suitable compounds for the triplet control layer, in particular triarylamine compounds, are described in EP 2 722 908 A1.

[0165] Emission layer (EML)

[0166] At least two EMLs can be independently formed on the HTL by vacuum deposition, spin coating, slot die coating, printing, casting, LB deposition, etc. When vacuum deposition or spin coating is used to form the EML, the conditions for deposition and coating can be similar to those for forming the HIL. However, the conditions for deposition and coating can vary depending on the compound used to form the EML.

[0167] Each emission layer (EML) can be formed by a combination of a host and a luminescent dopant. Examples of hosts are: Alq3, 4,4'-N,N'-dicarbazole-biphenyl (CBP), poly(n-vinylcarbazole) (PVK), 9,10-bis(naphthalen-2-yl)anthracene (ADN), 4,4',4”-tris(carbazol-9-yl)-triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI), 3-tert-butyl-9,10-di-2-naphthylanthracene (TBADN), stilbenylarylene (DSA), zinc bis(2-(2-hydroxyphenyl)benzothiazole) (Zn(BTZ)2), the following EML3, the following Compound 1 and the following Compound 2.

[0168]

[0169]

[0170] The luminescent dopant can be a phosphorescent or fluorescent emitter. Phosphorescent emitters and emitters that emit light via the thermally activated delayed fluorescence (TADF) mechanism can be preferred due to their higher efficiency. The emitter can be a small molecule or a polymer.

[0171] Examples of red luminescent dopants are: PtOEP, Ir(piq)3 and Btp2Ir(acac), but are not limited thereto. These compounds are phosphorescent emitters; however, fluorescent red luminescent dopants can also be used.

[0172]

[0173] Examples of phosphorescent green light-emitting dopants are Ir(ppy)3 (ppy = phenylpyridine), Ir(ppy)2(acac), and Ir(mpyp)3 shown below. Compound 3 is an example of a fluorescent green light-emitting body and its structure is shown below.

[0174]

[0175] Examples of phosphorescent blue light-emitting dopants are: F2Irpic, (F2ppy)2Ir(tmd), and Ir(dfppz)3, and truxene, the structures of which are shown below. Examples of fluorescent blue light-emitting dopants are: 4,4'-bis(4-diphenylaminostyryl)biphenyl (DPAVBi), 2,5,8,11-tetra-tert-butylperylene (TBPe), and Compound 4 below.

[0176]

[0177] Based on 100 parts by weight of the host, the amount of the light-emitting dopant can range from about 0.01 part by weight to about 50 parts by weight. Alternatively, the light-emitting layer can be composed of a light-emitting polymer. The EML can have a thickness of about 10 nm to about 100 nm, for example, a thickness of from about 20 nm to about 60 nm. When the thickness of the EML is within this range, the EML can have excellent luminescence without substantial impairment of the driving voltage.

[0178] Hole blocking layer (HBL)

[0179] The 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 holes from diffusing into the ETL. When the EML contains a phosphorescent dopant, the HBL can also have a triplet exciton blocking function.

[0180] When using vacuum deposition or spin coating to form the HBL, the conditions for deposition and coating can be similar to those for forming the HIL. However, the conditions for deposition and coating can vary depending on the compound used to form the HBL. Any compound commonly used to form the HBL can be used. Examples of compounds used to form the HBL include: diazole derivatives, triazole derivatives, and phenanthroline derivatives.

[0181] The thickness of the HBL can range from about 5 nm to about 100 nm, for example, from 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 substantial impairment of the driving voltage.

[0182] Electron transport layer (ETL)

[0183] The OLED according to the present invention may contain other electron transport layers (ETLs).

[0184] According to various embodiments, the OLED may include an electron transport layer, or an electron transport layer stack including at least a first electron transport sublayer and at least a second electron transport sublayer.

[0185] By appropriately adjusting the energy levels of specific layers of the ETL, the injection and transport of electrons can be controlled, and holes can be effectively blocked. Therefore, the OLED can have a long lifespan.

[0186] The electron transport layer of the organic light-emitting device may include an organic electron transport matrix (ETM) material. In addition, the electron transport layer may include one or more n-type dopants. There is no particular limitation on suitable compounds for the ETM. In one embodiment, the electron transport matrix compound is composed of covalently bonded atoms. Preferably, the electron transport matrix compound includes a conjugated system of at least 6 delocalized electrons, more preferably at least 10 delocalized electrons. In one embodiment, the conjugated system of delocalized electrons may be included in an aromatic or heteroaromatic structural moiety, as disclosed, for example, in documents EP 1 970 371A1 or WO 2013 / 079217 A1.

[0187] In one embodiment, the electron transport layer may be electrically doped with an n-type dopant. In another embodiment, the electron transport layer may include a second electron transport sublayer arranged closer to the cathode than the first electron transport sublayer, and only the second electron transport sublayer may include an n-type dopant.

[0188] The n-type dopant may be selected from electropositive elemental metals, and / or metal salts and metal complexes of electropositive metals, particularly elemental forms, salts, and / or complexes of metals selected from alkali metals, alkaline earth metals, and rare earth metals.

[0189] Electron injection layer (EIL)

[0190] An optional EIL that can facilitate electron injection from the cathode may be formed on the ETL, preferably directly on the electron transport layer. Examples of materials for forming the EIL include lithium 8-hydroxyquinoline (LiQ), LiF, NaCl, CsF, Li2O, BaO, Ca, Ba, Yb, Mg 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 for forming the EIL.

[0191] The thickness of the EIL can be in the range from about 0.1 nm to about 10 nm, for example, in the range from about 0.5 nm to about 9 nm. When the thickness of the EIL is within this range, the EIL can have satisfactory electron injection properties without substantial impairment of the driving voltage.

[0192] Cathode electrode

[0193] If an EIL exists, the cathode electrode is formed on the EIL. The cathode electrode can be formed of a metal, an alloy, a conductive compound, or a mixture thereof. The cathode electrode can have a low work function. For example, the cathode electrode can 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. Alternatively, the cathode electrode can also be formed of a transparent conductive oxide such as ITO or IZO. The cathode can contain more than 50 vol% of a metal selected from Ag and Au.

[0194] The thickness of the cathode electrode can be in the range from about 5 nm to about 1000 nm, for example, in the range from about 10 nm to about 100 nm. When the thickness of the cathode electrode is in the range from about 5 nm to about 50 nm, it can be transparent or translucent even if the cathode electrode is formed of a metal or a metal alloy.

[0195] The cathode can be a translucent metal cathode with a thickness less than 20 nm, preferably less than 15 nm, and even more preferably less than 12 nm.

[0196] It should be understood that the cathode electrode is not part of the electron injection layer or the electron transport layer.

[0197] Charge generation layer / hole generation layer

[0198] The charge generation layer (CGL) consists of a bilayer.

[0199] The charge generation layer is a pn junction connecting an n-type charge generation layer (electron generation layer) and a p-type charge generation layer (hole generation layer). Electrons are generated on the n side of the pn junction and injected into the layer adjacent in the direction of the anode. Similarly, holes are generated on the p side of the p-n junction and injected into the layer adjacent in the direction of the cathode.

[0200] The charge generation layer is used in tandem devices, for example, in a tandem OLED that includes two or more light-emitting layers between two electrodes. In a tandem OLED that includes two light-emitting layers, the n-type charge generation layer provides electrons for the first light-emitting layer disposed near the anode, while the p-type charge generation layer provides holes for the second light-emitting layer disposed between the first light-emitting layer and the cathode.

[0201] The hole generation layer may be composed of an organic matrix material doped with a p-type dopant. The matrix material suitable for use in the hole generation layer may be a material conventionally used as a hole injection and / or hole transport matrix material. Additionally, the p-type dopant for the hole generation layer may employ a conventional material. For example, the p-type dopant may be one selected from the following substances: tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), derivatives of tetracyanoquinodimethane, annulene derivatives, iodine, FeCl3, FeF3, and SbCl5. Additionally, the host may be one selected from the following substances: N,N'-bis(naphthalen-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).

[0202] According to the present invention, at least one n-type charge generation layer included in the organic light-emitting device of the present invention is the n-type sublayer defined herein. In the case where the organic light-emitting device includes more than one n-type charge generation layer (= n-type sublayer), it is only stipulated that at least one of these n-type charge generation layers is as defined herein.

[0203] In a preferred embodiment, the n-type charge generation layer comprises: a) a first organic compound; b) a second organic compound; and c) a zero-valent metal dopant, where the zero-valent metal dopant is a metal selected from alkali metals, alkaline earth metals, rare earth metals, Group 3 transition metals, and mixtures thereof. Or it comprises: a) a first organic compound, where the first organic compound is a compound containing at least one P=X group, where X is selected from O, S, or Se; b) a second organic compound, and the second organic compound contains at least one metal complex group, or contains two metal complex groups; and c) a zero-valent metal dopant, where the zero-valent metal dopant is a metal selected from alkali metals, alkaline earth metals, rare earth metals, Group 3 transition metals, and mixtures thereof.

[0204] In a preferred embodiment, the n-type charge generation layer consists of: a) a first organic compound; b) a second organic compound; and c) a zero-valent metal dopant, where the zero-valent metal dopant is a metal selected from alkali metals, alkaline earth metals, rare earth metals, Group 3 transition metals, and mixtures thereof. Or it consists of: a) a first organic compound, where the first organic compound is a compound containing at least one P=X group, where X is selected from O, S, or Se; b) a second organic compound, and the second organic compound contains at least one metal complex group, or contains two metal complex groups; and c) a zero-valent metal dopant, where the zero-valent metal dopant is a metal selected from alkali metals, alkaline earth metals, rare earth metals, Group 3 transition metals, and mixtures thereof.

[0205] In a preferred embodiment, the n-type charge generation layer may comprise a first organic compound and a second organic compound in a weight % ratio of 05:95 to 50:50, 10:90 to 50:50, 20:80 to 50:50, or 30:70 to 50:50, preferably 10:90 to 50:50, 20:80 to 50:50, or 30:70 to 50:50.

[0206] In a preferred embodiment, the n-type charge generation layer may comprise a first organic compound and a second organic compound in a weight % ratio of 95:05 to 50:50, 90:10 to 50:50, 80:20 to 50:50, or 70:30 to 50:50, preferably 90:10 to 50:50, 80:20 to 50:50, or 70:30 to 50:50.

[0207] Alternatively, other n-type charge generation layers (in addition to at least one) may be formed differently. If the n-type charge generation layer is not an n-type sublayer as defined herein, the n-type charge generation layer may be a pure n-type dopant, such as a layer of a positively charged metal, or may consist of an organic matrix material doped with an n-type dopant. In one embodiment, the n-type dopant may be an alkali metal, an alkali metal compound, an alkaline earth metal, or an alkaline earth metal compound. In another embodiment, the metal may be one selected from the group consisting of: Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy, and Yb. More specifically, the n-type dopant may be one selected from the group consisting of: Cs, K, Rb, Mg, Na, Ca, Sr, Eu, and Yb. Matrix materials suitable for use in the electron generation layer may be materials that are conventionally used as matrix materials for electron injection layers or electron transport layers. The matrix material may be, for example, one selected from the group consisting of: triazine compounds, hydroxyquinoline derivatives such as tris(8-hydroxyquinoline)aluminum, benzoxazole derivatives, and silole derivatives.

[0208] In one embodiment, the p-type charge generation layer may comprise a compound of the following chemical formula X.

[0209]

[0210] Wherein each of A 1 to A 6 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'), a substituted or unsubstituted straight-chain or branched C1-C 12An alkoxy group, a substituted or unsubstituted straight-chain or branched C1-C 12 alkyl group, a substituted or unsubstituted straight-chain or branched C2-C 12 alkenyl group, a substituted or unsubstituted aromatic or non-aromatic heterocycle, a substituted or unsubstituted aryl group, a substituted or unsubstituted monoarylamine or diarylamine, a substituted or unsubstituted aralkylamine, etc. In this text, each of R and R' above may be a substituted or unsubstituted C1-C 60 alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted 5- to 7-membered heterocycle, etc.

[0211] An example of such a p-type charge generation layer may be a layer containing CNHAT

[0212]

[0213] The hole generation layer may be disposed on top of the n-type charge generation layer.

[0214] Regarding the method for producing an organic electronic device, the above-described alternative embodiments can be applied with necessary modifications. For example, the charge generation layer can be produced to have an intermediate layer disposed between the n-type sublayer and the p-type sublayer.

[0215] According to one aspect, an OLED according to the present invention may include the following layer structure: a substrate is disposed adjacent to an anode electrode, the anode electrode is disposed adjacent to a first hole injection layer, the first hole injection layer is disposed adjacent to a first hole transport layer, the first hole transport layer is disposed adjacent to a first electron blocking layer, the first electron blocking layer is disposed adjacent to a first light-emitting layer, the first light-emitting layer is disposed adjacent to a first electron transport layer, the first electron transport layer is disposed adjacent to an n-type charge generation layer (n-type sublayer), the n-type charge generation layer is disposed adjacent to a hole generation layer (p-type sublayer), an intermediate layer may be provided between the n-type sublayer and the p-type sublayer, the hole generation layer is disposed adjacent to a second hole transport layer, the second hole transport layer is disposed adjacent to a second electron blocking layer, the second electron blocking layer is disposed adjacent to a second light-emitting layer, and an optional electron transport layer and / or an optional injection layer are disposed between the second light-emitting layer and the cathode electrode.

[0216] The stack of layers can be produced by techniques known in the art. For example, one or more of the layers in the stack can be produced by vacuum thermal evaporation.

[0217] Regarding the method for producing an organic electronic device, the deposition of multiple layers may include the step of depositing a p-type sublayer, and the deposition includes the evaporation and deposition of a fullerene compound in a vacuum. Preferably, all layers are deposited in a vacuum.

[0218] Details and definitions of the present invention

[0219] An organic compound as described herein is generally any chemical compound containing carbon (except for some compounds that are commonly referred to as inorganic, such as carbonates, cyanides, carbon dioxide, diamond, etc.). The term organic compound as used herein also encompasses compounds such as organometallic compounds, such as metallocenes, etc.

[0220] The term "zerovalent" as used herein refers to a metal in the oxidation state 0, i.e., particularly to a metal from which no electrons have been removed. Zerovalent metals can exist in the form of zerovalent atoms, pure metals, alloys, etc.

[0221] The term "trivalent" as used herein refers to a nitrogen atom having single and double bonds and containing a lone pair of electrons.

[0222] The term "metal complexing group" as used herein refers to a group capable of forming a bond with a metal ion.

[0223] The term "hydrocarbyl group" as used herein should be understood to encompass any organic group containing carbon atoms, particularly organic groups such as alkyl, aryl, heteroaryl, heteroalkyl, especially such groups as common substituents in organic electronics.

[0224] The term "conjugated system" as used herein refers to a system of alternating π - bonds and σ - bonds, or a molecule having alternating single and multiple bonds, i.e., double bonds, or a system having one or more diatomic structural units with π - bonds between its atoms that can be replaced by an atom with at least one lone electron pair, usually replaced by a divalent O or S atom.

[0225] The term "alkyl" as used herein should encompass straight - chain as well as branched - chain and cyclic alkyls. For example, C3 - alkyl can be selected from n - propyl and isopropyl. Similarly, C4 - alkyl encompasses n - butyl, sec - butyl, and tert - butyl. Similarly, C6 - alkyl encompasses n - hexyl and cyclohexyl.

[0226] C n The subscript number n in C refers to the total number of carbon atoms in the corresponding alkyl, arylene, heteroarylene, or aryl group.

[0227] The term "aryl" as used herein should encompass phenyl (C6 - aryl), fused aromatic compounds such as naphthalene, anthracene, phenanthrene, tetracene, etc. Also encompassed are biphenyl and lower or higher polyphenyls, such as terphenyl, etc. Also encompassed should be any other aromatic hydrocarbon substituent, such as fluorenyl, etc. Arylene, correspondingly heteroarylene, refers to a group linked to two other moieties.

[0228] The term "heteroaryl" as used herein refers to an aryl group in which at least one carbon atom is replaced by a heteroatom preferably selected from N, O, S, B, or Si.

[0229] The term "halogenated" refers to an organic compound in which one of its hydrogen atoms is replaced by a halogen atom. The term "perhalogenated" refers to an organic compound in which all of its hydrogen atoms are replaced by halogen atoms. The meanings of the terms "fluorinated" and "perfluorinated" should be understood similarly.

[0230] C n The subscript number n in - heteroaryl only refers to the number of carbon atoms and does not include the number of heteroatoms. In this context, it is obvious that a C3 heteroarylene group is an aromatic compound containing three carbon atoms, such as pyrazole, imidazole, oxazole, thiazole, etc.

[0231] For the purposes of the present invention, the expression "between" with respect to one layer between two other layers does not exclude the presence of additional layers that may be disposed between one layer and one of the two other layers. For the purposes of the present invention, the expression "in direct contact" with respect to two layers in direct contact with each other means that no additional layer is disposed between the two layers. A layer deposited on top of another layer is considered to be in direct contact with this layer.

[0232] In the context of this specification, the term "substantially non - emissive" or "non - emissive" means that the contribution of a compound or layer to the visible emission spectrum of a device is less than 10%, preferably less than 5%, relative to the visible emission spectrum. The visible emission spectrum is an emission spectrum with wavelengths of approximately ≥380 nm to approximately ≤780 nm.

[0233] Regarding the organic light - emitting device of the invention, the compounds mentioned in the experimental section can be most preferred.

[0234] An organic electroluminescent device (OLED) can be a bottom - emitting device or a top - emitting device.

[0235] On the other hand, it relates to a device comprising at least one organic electroluminescent device (OLED). A device comprising an organic light - emitting diode can be, for example, a display or a lighting panel.

[0236] In the present invention, unless otherwise defined in the claims or elsewhere in this specification, the terms defined below shall be taken to have these definitions.

[0237] In the context of this specification, the term "different" or "different from" with respect to a matrix material means that the matrix material is different in terms of its structural formula.

[0238] The energy levels of the highest occupied molecular orbital, also known as HOMO, and the lowest unoccupied molecular orbital, also known as LUMO, are measured in electron volts (eV).

[0239] The terms "OLED" and "organic light emitting diode" are used interchangeably and have the same meaning. As used herein, the term "organic electroluminescent device" can include both organic light emitting diodes and organic light emitting transistors (OLET).

[0240] As used herein, "weight percent", "wt%", "weight %", "percent by weight", "% weight" and variations thereof refer to expressing a composition, component, substance or reagent as the weight of the corresponding component, substance or reagent of the electron transport layer divided by the total weight of its corresponding electron transport layer, and multiplied by 100. It should be understood that the amount of the total weight percentage of all components, substances and reagents of the corresponding electron transport layer and electron injection layer is selected such that it does not exceed 100 weight %.

[0241] As used herein, "volume percent", "vol%", "percent by volume", "% volume" and variations thereof refer to expressing a composition, component, substance or reagent as the volume of the corresponding component, substance or reagent of the electron transport layer divided by the total volume of its corresponding electron transport layer, and multiplied by 100. It should be understood that the amount of the total volume percentage of all components, substances and reagents of the cathode layer is selected such that it does not exceed 100 volume %.

[0242] Whether or not explicitly stated, all numerical values herein are assumed to be modified by the term "about". As used herein, the term "about" refers to a variation in the quantity that can occur. Whether or not modified by the term "about", the claims include equivalents of the recited quantity.

[0243] It should be noted that unless the context clearly dictates otherwise, as used in this specification and the claims, the singular forms "a", "an", "the" and "said" include plural referents.

[0244] The terms "free of", "not containing", "not comprising" do not exclude impurities. Impurities have no technical effect on the object to be achieved by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0245] In conjunction with the drawings, from the following description of exemplary embodiments, these and / or other aspects and advantages of the present invention will become apparent and more readily understood, in which:

[0246] Figure 1 is a schematic representation of a stack of tandem organic light emitting diode devices;

[0247] Figure 2 is a schematic representation of a stack of another tandem organic light emitting diode device;

[0248] Figure 3 is a schematic representation of a stack of other tandem organic light emitting diode devices. Detailed Embodiments

[0249] Now, exemplary embodiments of the present invention will be described in detail, and examples thereof are shown in the accompanying drawings, where the same reference numerals always refer to the same elements. To illustrate aspects of the present invention, exemplary embodiments will be described below with reference to the figures.

[0250] In this document, when a first element is said to be formed or disposed "on" a second element, the first element can be directly disposed on the second element, or one or more other elements can be disposed therebetween. When a first element is said to be "directly" formed or disposed "on" a second element, no other elements are disposed therebetween.

[0251] In Figure 1 a first hole injection layer 6, a first hole transport layer 7, and a first electron blocking layer 8 are disposed between the anode 3 and the first light-emitting layer 9. A first electron transport layer 10 is disposed between the first light-emitting layer 9 and the charge generation layer 5 (n-type sublayer 5a and p-type sublayer 5b). A second hole injection layer 11, a second hole transport layer 12, and a second electron blocking layer 13 are disposed between the charge generation layer 5 and the second light-emitting layer 14. A second electron transport layer 15 is disposed between the second light-emitting layer 14 and the cathode 4.

[0252] Figure 2 shows a schematic representation of another tandem OLED. Additionally, a stack 1 of layers disposed on the substrate 2 includes an intermediate layer 16 between the n-type sublayer 5a and the p-type sublayer 5b.

[0253] Figure 3 shows a schematic representation of other tandem OLEDs. In the stack 1 of layers disposed on the substrate 2, the n-type sublayer 5a of the charge generation layer 5 includes a first n-type sublayer 5a1 and a second n-type sublayer 5a2. In an alternative embodiment (not shown), the charge generation layer 5 of the tandem OLED in FIG. 5 can include the intermediate layer 16.

[0254] 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.

[0255] Experimental section

[0256] Preparation of the novel compounds of the present invention

[0257] Dimethyl(3-(4-(3-(2-phenylbenzo[h]quinazolin-4-yl)phenyl)naphthalen-1-yl)phenyl)phosphine oxide (E7)

[0258] In a nitrogen-flushed flask, 4-(3-(dimethylphosphoryl)phenyl)naphthalen-1-yl trifluoromethanesulfonate (50.0 g, 116.72 mmol) and 2,4-diphenyl-6-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyrimidine (65.9 g, 152 mmol, 1.3 equiv) were dissolved together with Pd(PPh3)4 (0.12 mmol, 1.35 g, 0.01 equiv) and K2CO3 (32.3 g, 234 mmol, 2.0 equiv) in a degassed mixture of toluene, ethanol, and water. The reaction mixture was heated under reflux for five hours. After cooling to room temperature, the phases were separated; the organic phase was washed with brine and filtered through a gel pad of Florisil with toluene. After removing half of the solvent, the product was precipitated with cyclohexane. The precipitate was filtered off by suction and washed with cyclohexane. Then, the crude product was recrystallized from toluene / ethanol. The purified solid was separated by sublimation as a fine powder with an HPLC purity of 99.95%.

[0259] 2-Phenyl-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)benzo[h]quinazoline

[0260] The flask was flushed with nitrogen and equipped with 4-(3-bromophenyl)-2-phenylbenzo[h]quinazoline (CAS 1502825-34-4, 45.0 g, 109.41 mmol) and 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bis(1,3,2-dioxaborolane) (CAS 73183-34-3, 33.34 g, 131.29 mmol, 1.2 equiv). The starting materials were dissolved in dry dimethylformamide together with [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (CAS 72287-26-4, 2.4 g, 3.28 mmol, 0.03 equiv) and KOAc (26.8 g, 273.53 mmol, 2.05 equiv). The reaction mixture was stirred overnight under reflux. After cooling to room temperature, the solvent was removed in vacuo and the product was dissolved in dichloromethane. The organic phase was washed twice with water and dried over Na2SO4. After filtration through a gel pad of Florisil, the product was precipitated with cyclohexane. After filtration, the product was separated as a fine solid with an HPLC purity of 99.17%.

[0261] (3-(4-Chloronaphthalen-1-yl)phenyl)dimethylphosphine oxide

[0262] The flask was flushed with nitrogen and charged with (4-chloronaphthalen-1-yl)boronic acid (10.0 g, 48.1 mmol), (3-bromophenyl)dimethylphosphine oxide (11.3 g, 48.4 mmol, 1.0 equiv), Pd(PPh3)4 (0.98 g, 0.85 mmol, 0.0175 equiv) and K2CO3 (10.0 g, 72.6 mmol, 1.5 equiv). A degassed mixture of ethanol and water was added and the reaction mixture was heated to reflux overnight under a nitrogen atmosphere. After cooling to room temperature, the aqueous phase was separated and washed with toluene. The combined organic phases were filtered through a plug of Florisil and washed with toluene. After removal of most of the solvent, the product was precipitated with n-hexane. After filtration, the solid was recrystallized once from methyl tert-butyl ether and once from toluene / methanol. The solid was filtered and washed with ethyl acetate. The product was obtained as a light brown solid with an HPLC purity of 99.65%.

[0263] Dimethyl(3-(4-(3-(2-phenylbenzo[h]quinazolin-4-yl)phenyl)naphthalen-1-yl)phenyl)phosphine oxide (E8)

[0264] In a nitrogen-flushed flask, (3-(4-chloronaphthalen-1-yl)phenyl)dimethylphosphine oxide (10.4 g, 32.75 mmol, 1.0 equiv) and 2-phenyl-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)benzo[h]quinazoline (15.0 g, 32.75 mmol) were dissolved together with chloro(crotyl)(2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl)palladium(II) (CAS 1798781-99-3, 0.7 g, 1.16 mmol, 0.035 equiv) and K3PO4 (17.4 g, 81.9 mmol, 2.5 equiv) in a degassed mixture of dioxane and water. The reaction mixture was stirred at reflux overnight. After cooling to room temperature, the precipitate was filtered off and washed with dioxane, water and ethanol. The solid was recrystallized from dichloromethane and heated with toluene. The product was filtered and washed with toluene and hexane. After sublimation as the final purification step, the product was isolated as a fine solid with an HPLC purity of 99.98%. After cooling to room temperature, the precipitate was filtered off and washed with dioxane After sublimation as the final purification step, the product was isolated as a fine solid with an HPLC purity of 99.98%.

[0265] Supporting materials for device experiments

[0266] F1 is

[0267] CAS 1242056-42-3

[0268] F2 is

[0269] CAS 1464822-27-2

[0270] F3 is

[0271] CAS 1607480-22-7

[0272] F4 is

[0273] CAS 1955546-40-3

[0274] F5 is

[0275] CAS 2244287-14-5

[0276] F6 is

[0277] CAS 721969-94-4

[0278] F7 is

[0279] CAS 2646631-43-6

[0280] C1 is

[0281] CAS 2437303-42-7

[0282] PD1 is

[0283] CAS 1224447-88-4

[0284] H09 is a light-emitting body main body and BD200 is a blue fluorescent light-emitting dopant, both of which are available from SFC, Korea.

[0285] Standard procedures

[0286] Voltage stability

[0287] The OLED is driven by a constant current circuit. These circuits can supply a constant current within a given voltage range. The wider the voltage range, the wider the power loss of such a device. Therefore, it is necessary to minimize the change in the driving voltage during driving.

[0288] The driving voltage of the OLED is temperature-dependent. Therefore, it is necessary to judge the voltage stability in thermal equilibrium. Thermal equilibrium is reached after one hour of driving.

[0289] The voltage stability is measured by taking the difference in the driving voltage after driving for 50 hours at a constant current density and after driving for 1 hour. Here, a current density of 30 mA / cm 2 is used. The measurement is done at room temperature.

[0290] dU [V] = U(50 h, 30 mA / cm 2 ) – U(1 h, 30 mA / cm 2 )

[0291] Examples

[0292] 1) Blue tandem OLED

[0293] Table 1a schematically describes the model device.

[0294] Table 1a:

[0295]

[0296] The results of the corresponding experiments are summarized in Table 1b.

[0297] Table 1b

[0298]

[0299] Compared with Device No. 1 containing the prior art ETL with the first electron transport compound according to the invention diluted with Compound C1, the other devices according to the claims of the invention containing an ETL composed of the undiluted first electron transport compound show lower operating voltages and / or higher current efficiencies.

[0300] In addition, the novel compound E7 is compared with E1 in another blue tandem OLED, which is different from the above device in that the two light-emitting layers contain Compound BH-1 instead of H09 and contain Compound BD-1 instead of BD200, where

[0301] BH1 is

[0302] CAS 2457172-82-4,

[0303] BD1 is

[0304] CAS 2482607-57-6.

[0305] The results are summarized in Table 1c.

[0306] Table 1c

[0307]

[0308] Compared with its closest prior art analogue, i.e., E1 which contains an anthracene structural moiety, the novel compound E7 (alternatively containing a naphthalene structural moiety) surprisingly enables even more improvement in current efficiency.

[0309] The features disclosed in the foregoing description and the dependent claims can be realized individually and in any combination thereof, and thus in its various forms as materials to achieve the aspects of the present disclosure set forth in the independent claims.

Claims

1. An organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode, a first electron transport layer, a first light-emitting layer, and a charge generation layer; Wherein - The first light-emitting layer, the first electron transport layer, and the charge generation layer are arranged between the anode and the cathode; - The charge generation layer comprises an n-type sublayer; - The first electron transport layer is in direct contact with the n-type sublayer; - The first electron transport layer is arranged between the first light-emitting layer and the n-type sublayer; - The first electron transport layer is composed of a first electron transport compound, and the first electron transport compound comprises a functional group of formula (1) and selected from C6 to C 60 aryl and C2 to C 60 heteroaryl structural moieties, Wherein - X is selected from O, S, or Se; -R 1 and R 2 are independently selected from substituted or unsubstituted C1 to C 16 alkyl groups, wherein the substituents of the substituted C1 to C 16 alkyl groups are selected from C6 to C 18 aryl or C2 to C 12 heteroaryl; Wavy line A covalent bond representing the connection of the P atom of the functional group (1) to the rest of the first electron transport compound; - The n-type sublayer comprises a second electron transport compound and a metal; - Wherein the second electron transport compound comprises at least two N atoms; And - The metal is selected from alkaline earth metals and rare earth metals.

2. The organic electroluminescent device according to claim 1, wherein the first electron transport compound has formula (2) Wherein - X is selected from O, S, or Se; -Ar 1 selected from unsubstituted or substituted C6-C 60 aryl and C2-C 60 heteroaryl, - wherein one or more substituents of the substituted C2-C 60 heteroarylene, C6-C 60 arylene are each independently selected from D, C1-C 12 alkyl, C1-C 12 alkoxy, CN, OH, halogen, C6-C 32 aryl or C2-C 25 heteroaryl; - n is 1 or 2; -L 1 Selected from a single bond, a C1-C4 alkylene group, or a substituted or unsubstituted C6-C 36 arylene group; - wherein one or more substituents of the substituted C6 to C 36 arylene are independently selected from D, C1 to C 12 alkyl, C1 to C 12 alkoxy, CN, OH, halogen, C6 to C 32 aryl or C2 to C 25 heteroaryl; -L 2 selected from a single bond or a C1-C6 alkyl group -R 1 and R 2 are independently selected from substituted or unsubstituted C1 to C 16 alkyl - wherein the substituent of the substituted C1 to C 16 alkyl is selected from C6 to C 18 aryl or C2 to C 12 heteroaryl.

3. The organic electroluminescent device according to claim 1 or 2, wherein X is O.

4. The organic electroluminescent device according to claim 2 or 3, wherein L 1 is a substituted or unsubstituted C6 to C 36 arylene group.

5. The organic electroluminescent device according to claim 4, wherein L 2 is a single bond.

6. The organic electroluminescent device according to any one of the preceding claims, wherein Ar 1 is independently selected from the following structures and where Ar 1 combines with L at *1 1 .

7. The organic electroluminescent device according to any one of the preceding claims, wherein R 1 and R 2 are independently selected from C1 to C8 alkyl groups.

8. The organic electroluminescent device according to any one of the foregoing claims, wherein the first electron transport compound is selected from E1 to E8 9. The organic electroluminescent device according to any one of the foregoing claims, wherein the second electron transport compound comprises a moiety composed of 2 to 6 fused aromatic rings.

10. The organic electroluminescent device according to claim 9, wherein the moiety composed of 2 to 6 fused aromatic rings is an aromatic moiety; preferably, the aromatic moiety is selected from naphthalene, anthracene, phenanthrene, and pyrene.

11. The organic electroluminescent device according to any one of the preceding claims, wherein the second electron transport compound comprises a heteroaromatic moiety selected from diazine, oxadiazole, benzimidazole, imidazopyridine, phenanthroline, quinazoline, benzoquinazoline, and quinoxaline, wherein the corresponding heteroaromatic moiety is unsubstituted or substituted with a C6-C 18 aryl or a C2-C 12 heteroaryl, wherein the C6-C 18 aryl or a C2-C 12 heteroaryl may each be independently substituted with one or more groups selected from C1-C4 alkyl groups.

12. The organic electroluminescent device according to any one of the foregoing claims, the organic electroluminescent device further comprising a first hole blocking layer arranged between the first electron transport layer and the first light-emitting layer.

13. The organic electroluminescent device according to any one of the foregoing claims, wherein the metal is a rare earth metal, preferably Yb.

14. A display device, the display device comprising the organic electroluminescent device according to any one of the foregoing claims.

15. A compound, the compound having a formula selected from E7 and E8

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