Luminescent organic electroluminescent devices

Abstract

The present invention relates to an organic electroluminescent device, which comprises a light-emitting layer B, wherein the light-emitting layer B comprises a host material H B , first thermally activated delayed fluorescence (TADF) material E B and an emitter material S B .

Description

[0001] The present invention relates to an organic electroluminescent device comprising a light-emitting layer B, wherein the light-emitting layer B comprises a host material H B , Thermally activated delayed fluorescence (TADF) material E B and an emitter material S B .

[0002] Description of the Invention

[0003] Organic electroluminescent devices, such as organic light-emitting diodes (OLEDs), light-emitting electrochemical cells (LECs), and light-emitting transistors, which contain one or more organic-based light-emitting layers, are becoming increasingly important. OLEDs, in particular, are promising devices for use in electronic products such as screens, displays, and lighting. Compared to most electroluminescent devices, which are primarily based on inorganic substances, organic-based organic electroluminescent devices are generally quite flexible and can be produced in particularly thin layers. OLED-based screens and displays already available today offer particularly advantageous vivid colors, contrast, and considerable efficiency in terms of energy consumption.

[0004] The core element of an organic electroluminescent device for generating light is a light-emitting layer placed between an anode and a cathode. When a voltage (and current) is applied to the organic electroluminescent device, holes and electrons are injected into the light-emitting layer from the anode and cathode, respectively. Typically, there is a hole transport layer located between the light-emitting layer and the anode, and an electron transport layer located between the light-emitting layer and the cathode. The different layers are arranged in sequence. High-energy excitons are then generated by the recombination of holes and electrons. The decay of this excited state (e.g., a singlet state such as S1 and / or a triplet state such as T1) to the ground state (S0) results in the desired luminescence.

[0005] To achieve efficient energy transfer and emission, organic electroluminescent devices (OLEDs) contain one or more host compounds and one or more emitter compounds as dopants. Consequently, the challenges in producing OLEDs are to increase the device's illumination level (i.e., brightness per unit current), achieve the desired spectrum, and achieve a desired (long) lifetime.

[0006] Currently, there is still a lack of efficient and stable OLEDs emitting in the visible spectrum. Therefore, there is still an unmet technical need for organic electroluminescent devices with long lifetime and high quantum yield.

[0007] Surprisingly, the present invention has found that a light-emitting layer of an organic electroluminescent device, comprising a thermally activated delayed fluorescence (TADF) material, an emitter material and a host material, can provide an organic electroluminescent device with good lifetime and quantum yield and emitting visible light.

[0008] Therefore, one aspect of the present invention relates to an organic electroluminescent device, comprising a light-emitting layer B, wherein the light-emitting layer B comprises:

[0009] (i) Main material H B , which has the lowest excited singlet energy level S1 H , the lowest excited triplet state energy level T1 H and has energy E HOMO (H B )'s highest occupied molecular orbital HOMO (H B );

[0010] (ii) First Thermally Activated Delayed Fluorescence (TADF) Material E B , which has the lowest excited singlet energy level S1 E , the lowest excited triplet state energy level T1 E , and has energy E HOMO (E B )'s highest occupied molecular orbital HOMO(E B ));and

[0011] (iii) Emitter material S B , which has the lowest excited singlet energy level S1 S and has energy E HOMO (S B )'s highest occupied molecular orbital HOMO(S B );

[0012] The relationships expressed by the following formulas (1) to (5) hold true:

[0013] S1 H >S1 E (1)

[0014] S1 H >S1 S (2)

[0015] S1 E >S1 S (3)

[0016] E HOMO (E B )>E HOMO (S B ) (4)

[0017] E HOMO (E B )>E HOMO (H B ) (5).

[0018] According to the present invention, the host material H BThe lowest excited singlet state energy is higher than that of the first thermally activated delayed fluorescence (TADF) material E B The lowest excited singlet state energy.

[0019] Main material H B The energy of the lowest excited singlet state is higher than that of the emitter material S B The lowest excited singlet state of the first TADF material E B The lowest excited singlet state energy is higher than that of the emitter material S B The lowest excited singlet state.

[0020] In one embodiment of the present invention, the relationship expressed by formula (3a) holds:

[0021] S1 E –S1 S ≤0.4eV (3a).

[0022] In one embodiment of the present invention, the relationship expressed by formula (3b) holds:

[0023] S1 E –S1 S ≤0.3eV (3b).

[0024] In one embodiment of the present invention, the relationship expressed by formula (3c) applies:

[0025] S1 E –S1 S ≤0.2eV (3c).

[0026] In one embodiment of the present invention, the relationship expressed by one of the following formulas (6) and (7) holds:

[0027] 0.2eV≤E HOMO (E B )-E HOMO (S B )≤0.8eV (6).

[0028] 0.2eV≤E HOMO (E B )-E HOMO (H B )≤0.8eV (7).

[0029] In this embodiment, the TADF material E B The energy of the highest occupied molecular orbital of the emitter material S B The energy of the highest occupied molecular orbital of is at least 0.2 eV, at most 0.8 eV, preferably at least 0.3 eV, at most 0.7 eV, in particular at least 0.4 eV, at most 0.6 eV higher.

[0030] In an alternative embodiment of the present invention, the TADF material E B The energy of the highest occupied molecular orbital is higher than that of the host material H B The energy of the highest occupied molecular orbital of is at least 0.2 eV, at most 0.8 eV, preferably at least 0.3 eV, at most 0.7 eV, in particular at least 0.4 eV, at most 0.6 eV higher.

[0031] As used herein, the terms "TADF material" and "TADF emitter" and "TADF emitter" are to be understood interchangeably. When terms such as "emitter" or "emitter compound" are used, this is to be understood as preferably referring to the TADF material of the present invention, in particular one or more of the TADF materials designated as E B materials.

[0032] According to the present invention, the TADF material is characterized in that it exhibits a ΔE of less than 0.4 eV. ST ΔE is preferably less than 0.3 eV, more preferably less than 0.2 eV. ST The value corresponds to the energy difference between the lowest excited singlet state (S1) and the lowest excited triplet state (T1),

[0033] Therefore, in an embodiment of the present invention, the TADF material E B is characterized by its corresponding S1 E and T1 E The energy difference ΔE between ST The value is less than 0.4eV. In a preferred embodiment of the present invention, the TADF material E B is characterized by its ΔE ST The value is less than 0.3 eV, preferably less than 0.2 eV.

[0034] In one embodiment of the present invention, the relationship expressed by formula (8) holds: S1 S >T1 E (8), where the lowest excited singlet energy level S1 S The energy is higher than the lowest excited triplet state T1 E .

[0035] In a preferred embodiment, the host material H B The lowest excited triplet state (T1 H ) is higher than the energy of TADF material E B The lowest excited triplet state (T1 E ): T1 H >T1 E .

[0036] In a preferred embodiment, the host material H BThe lowest excited triplet state (T1 H ) has a higher energy than the emitter material S B The lowest excited triplet state (T1 S ): T1 H >T1 S .

[0037] In one embodiment of the present invention, the TADF material E B With emitter material S B The mass ratio (S B :E B )>1. In one embodiment of the present invention, the mass ratio S B :E B In the range of 1.5:1 to 30:1, in the range of 2:1 to 25:1, or in the range of 3:1 to 20:1. For example, the mass ratio S B :E B In the range of approximately 15:1, 12:1, 10:1 or 8:1.

[0038] As used herein, the terms organic electroluminescent device and optoelectronic light emitting device may be understood in the broadest sense as any device comprising a light emitting layer B comprising a host material H B TADF material E B and emitter material S B .

[0039] It should be understood that the light-emitting layer B may also contain more than one TADF material E B and / or more than one emitter material S B , each having the properties as described herein. According to the present invention, the light-emitting layer B comprises at least one TADF material E B and at least one emitter material S B , each having the characteristics described herein. According to one embodiment of the present invention, the light-emitting layer B comprises a TADF material E B and an emitter material S B , each having properties as described herein.

[0040] As used herein, the terms organic electroluminescent device and optoelectronic light emitting device may be understood in the broadest sense as any device comprising a light emitting layer B comprising a host material H B TADF material E B and emitter material S B .

[0041] An organic electroluminescent device can be broadly understood as any device based on organic materials, which is suitable for emitting light in the visible or near ultraviolet (UV) range, i.e., a wavelength range of 380-800 nm. More preferably, the organic electroluminescent device is capable of emitting light in the visible range, i.e., a wavelength of 400 to 800 nm.

[0042] In a preferred embodiment, the organic electroluminescent device is selected from the group consisting of an organic light emitting diode (OLED), a light emitting electrochemical cell (LEC) and a light emitting transistor.

[0043] Particularly preferably, the organic electroluminescent device is an organic light emitting diode (OLED).Alternatively, the organic electroluminescent device as a whole may be opaque, semi-transparent or (substantially) transparent.

[0044] In the present invention, the term "layer" preferably refers to a body having a generally planar geometric shape. The thickness of the light-emitting layer B is preferably 1 mm or less, more preferably 0.1 mm or less, further preferably 10 μm or less, even more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0045] Those skilled in the art will appreciate that the light-emitting layer B is generally used in the organic electroluminescent device of the present invention. Preferably, the organic electroluminescent device comprises at least the following layers: at least one light-emitting layer B, at least one anode layer A and at least one cathode layer C.

[0046] Preferably, the anode layer A comprises a material selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicon, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and mixtures of two or more thereof. Preferably, the cathode layer C comprises a material selected from the group consisting of Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, In, W, Pd, LiF, Ca, Ba, Mg, and mixtures or alloys of two or more thereof.

[0047] Preferably, the light-emitting layer B is located between the anode layer A and the cathode layer C. Thus, a general arrangement is preferably ABC. This does not, of course, exclude the presence of one or more optional further layers, which may be present on each side of A, B and / or C.

[0048] In a preferred embodiment, the organic electroluminescent device comprises at least the following layers:

[0049] A) an anode layer A comprising an oxide selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicon, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and a mixture of two or more thereof;

[0050] B) light-emitting layer B; and

[0051] C) a cathode layer C comprising a material selected from the group consisting of Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, In, W, Pd, LiF, Ca, Ba, Mg, and mixtures or alloys of two or more thereof,

[0052] The light-emitting layer B is located between the anode layer A and the cathode layer C.

[0053] In one embodiment, when the organic electroluminescent device is an OLED, it may optionally include the following layer structure:

[0054] A) an anode layer A, illustratively comprising indium tin oxide (ITO);

[0055] HTL) hole transport layer HTL;

[0056] B) a light-emitting layer B according to the invention as described herein;

[0057] ETL) electron transport layer ETL; and

[0058] C) Cathode layer, exemplarily comprising Al, Ca and / or Mg.

[0059] Preferably, the layer sequence here is A-HTL-B-ETL-C.

[0060] Additionally, the organic electroluminescent device may optionally include one or more protective layers to protect the device from harmful substances in the environment, including, for example, moisture, steam and / or gases.

[0061] Preferably, the anode layer A is located on the surface of the substrate. The substrate can be formed from any material or material combination. Most commonly, a glass sheet is used as the substrate. Alternatively, a thin metal sheet (e.g., copper, gold, silver, or aluminum film) or a plastic film or sheet can be used. There is great flexibility in this regard. The anode layer A mainly consists of a material that can form a (substantially) transparent film. Since at least one of the two electrodes should be (substantially) transparent to allow light to be emitted from the OLED, the anode layer A or the cathode layer C is transparent. Preferably, the anode layer A contains a large amount of or consists entirely of a transparent conductive oxide (TCO).

[0062] Such an anode layer A may illustratively include indium tin oxide, aluminum zinc oxide, fluorine tin oxide, indium zinc oxide, PbO, SnO, zirconium oxide, molybdenum oxide, vanadium oxide, tungsten oxide, graphite, doped Si, doped Ge, doped GaAs, doped polyaniline, doped polypyrrole and / or doped polythiophene.

[0063] Particularly preferably, the anode layer A consists (essentially) of indium tin oxide (ITO) (e.g. (InO3) 0.9 (SnO2) 0.1). The roughness of the anode layer A caused by the transparent conductive oxide (TCO) can be compensated by using a hole injection layer (HIL). In addition, the HIL can promote the injection of quasi-charge carriers (i.e., holes) and promote the transport of quasi-charge carriers from the TCO to the hole transport layer (HTL). The hole injection layer (HIL) may include poly (3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), MoO2, V2O5, CuPC or CuI, in particular a mixture of PEDOT and PSS. The hole injection layer (HIL) can also prevent the diffusion of metal from the anode layer A to the hole transport layer (HTL). The HIL may exemplarily include

[0064] PEDOT:PSS (poly-3,4-ethylenedioxythiophene:polystyrene sulfonate), PEDOT (poly-3,4-ethylenedioxythiophene), mMTDATA (4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine), Spiro-TAD (2,2',7,7'-tetrakis(n,n-diphenylamino)-9,9'-spirobifluorene), DNTPD (N1,N1'-(biphenyl-4,4'-diyl)bis(N1-phenyl-N4,N4-di-m-tolylphenyl-1,4-diamine)) ,NPB (N,N'-nis-(1-naphthyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine), NPNPB (N,N'-diphenyl-N,N'-bis-[4-(N,N-diphenyl-amino)-phenyl]benzidine), MeO-TPD (N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine), HAT-CN (1,4,5,8,9,11-hexaazabenzohexacarbonitrile) and / or Spiro-NPD (N,N'-diphenyl-N,N'-bis-(1-naphthyl)-9,9'-spirobifluorene-2,7-diamine)

[0065] Adjacent to the anode layer A or the hole injection layer (HIL), a hole transport layer (HTL) is generally provided. Any hole transport compound can be used herein. For example, electron-rich heteroaromatic compounds such as triarylamines and / or carbazoles can be used as hole transport compounds. The HTL can lower the energy barrier between the anode layer A and the light-emitting layer B (serving as the light-emitting layer (EML)). The hole transport layer (HTL) can also be an electron blocking layer (EBL). Preferably, the hole transport compound has a higher energy level triplet state T1. For example, the hole transport layer (HTL) may contain a star-shaped heterocycle, such as tris(4-carbazolyl-9-ylphenyl)amine (TCTA), poly-TPD (poly(4-butylphenyl-diphenyl-amine)), α-NPD (poly(4-butylphenyl-diphenyl-amine)), TAPC (4,4′-cyclohexyl-bis[N,N-bis(4-methylphenyl)aniline]), 2-TNATA (4,4′,4″-tris[2-naphthyl(phenyl)-amino]triphenylamine), Spir o-TAD, DNTPD, NPB, NPPNB, MeO-TPD, HAT-CN, and / or TrisPcz (9,9'-diphenyl-6-(9-phenyl-9H-carbazol-3-yl)-9H,9'H-3,3'-bicarbazole). Furthermore, the HTL may include a p-doped layer, which may be composed of an inorganic or organic dopant in an organic hole-transporting matrix. Transition metal oxides such as vanadium oxide, molybdenum oxide, or tungsten oxide may be used as inorganic dopants, for example.

[0066] Tetrafluorotetracyanoquinodimethane (F4-TCNQ), copper pentafluorobenzoate (Cu(I)pFBz), or a transition metal complex may be exemplarily used as the organic dopant.

[0067] The EBL may illustratively include mCP (1,3-bis(carbazol-9-yl)benzene), TCTA, 2-TNATA, mCBP (3,3-bis(9H-carbazol-9-yl)biphenyl), 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzothiophen-2-yl)phenyl]-9H-carbazole, phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzofuranyl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzothiophene)phenyl]-9H-carbazole, tris-Pcz, CzSi(9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole) and / or DCB (N,N'-dicarbazolyl-1,4-dimethylbenzene).

[0068] In one embodiment of the present invention, the emitter material S B Selected from fluorescent emitters and organic TADF emitters, wherein the organic TADF emitter is characterized by its ΔE STThe value is less than 0.4eV.

[0069] In a preferred embodiment, the emitter material S B It is an organic TADF emitter.

[0070] In one embodiment of the present invention, S B The lowest excited triplet state energy level T1 S With E B The lowest excited triplet state energy level T1 E The relationship between is expressed by formula (9):

[0071] T1 S >T1 E (9).

[0072] In one embodiment of the present invention, the relationship expressed by the following formula holds true

[0073] T1 S –T1 E ≤0.4eV.

[0074] In one embodiment of the present invention, the relationship expressed by the following formula holds true

[0075] T1 S –T1 E ≤0.3eV.

[0076] In one embodiment of the present invention, the relationship expressed by the following formula holds true

[0077] T1 S –T1 E ≤0.2eV.

[0078] In a preferred embodiment, S1 E >S1 S , T1 S >T1 E and S1 E -T1 S ≤0.4eV. In other words, the TADF material E B The lowest excited singlet state energy is higher than that of the emitter material S B The lowest excited singlet state of the emitter material S B The lowest excited triplet energy is higher than the lowest excited triplet energy E of TADF material B In a preferred embodiment, the energy differences of all four states are in the range of 0.4 eV or less, preferably in the range of 0.3 eV or less, in particular in the range of 0.2 eV or less.

[0079] Since TADF material E B and S BThe low energy difference between the lowest excited singlet and triplet states, E B and S B The exciton transfer between different states of is fully realized. In addition, due to the low energy difference, the transfer between different multiplicity states can be achieved.

[0080] This may include energy transfer such as

[0081] (a) From the singlet state of the TADF material to the singlet state of the emitter material,

[0082] (b) From the triplet state of the TADF material to the triplet state of the emitter material,

[0083] (c) from a singlet state of the TADF material to a triplet state of the emitter material, and / or

[0084] (d) From the triplet state of TADF materials to the singlet state of other emitter materials.

[0085] (e) From the singlet state of the emitter material to the singlet state of the TADF material,

[0086] (f) From the triplet state of the emitter material to the triplet state of the TADF material,

[0087] (g) from a singlet state of the emitter material to a triplet state of the TADF material, and / or

[0088] (h) From the triplet state of the emitter material to the singlet state of other TADF materials.

[0089] Surprisingly, it was found that the main contribution to the emission band of the optoelectronic device according to the invention is attributable to the emitter material S B emission, which indicates that the energy from E B to S B Full transfer.

[0090] In another embodiment of the present invention, the relationship represented by formula (10a), (10b) or (10c) holds:

[0091] E HOMO (H B )>E HOMO (S B ) (10a)

[0092] E HOMO (S B )>E HOMO (H B ) (10b)

[0093] -0.1eV≤E HOMO (H B )-E HOMO(S B )≤0.1eV (10c).

[0094] In a preferred embodiment, the emitter material S B With energy E HOMO (S B )'s highest occupied molecular orbital HOMO(S B ) and the host compound H B With energy E HOMO (H B )'s highest occupied molecular orbital HOMO (H B ), where E HOMO (E B )-E HOMO (H B )≤0.3eV and E HOMO (E B )-E HOMO (H B )≥-0.3eV. In other words, with the emitter material S B HOMO(S B ) compared to the main body H B HOMO (H B ) can be higher or lower in energy, but the difference does not exceed 0.3 eV, more preferably does not exceed 0.2 eV.

[0095] In another embodiment of the present invention, the LUMO (E B ) of E B The lowest unoccupied molecular orbital LUMO (E B ) with energy E LUMO (S B ) B The lowest unoccupied molecular orbital LUMO (S B ) is expressed by formula (11):

[0096] E LUMO (E B )>E LUMO (S B ) (11).

[0097] In one embodiment of the present invention, the energy is E LUMO (S B ) B The lowest unoccupied molecular orbital LUMO (S B ) has an energy higher than that of E LUMO (S B ) B The lowest unoccupied molecular orbital LUMO (S B), and has energy E LUMO (H B ) B The lowest unoccupied molecular orbital LUMO (H B ) has an energy higher than that of E LUMO (S B ) B The lowest unoccupied molecular orbital LUMO (S B ), the relationship can be expressed by equations (11) and (11a): E LUMO (E B )>E LUMO (S B ) (11)

[0098] E LUMO (H B )>E LUMO (S B ) (11a).

[0099] In one embodiment of the present invention, the relationship represented by one of the following equations (11b) and (11c) holds:

[0100] 0.2eV≤E LUMO (H B )-E LUMO (E B )≤0.8eV (11b).

[0101] 0.2eV≤E LUMO (E B )-E LUMO (S B )≤0.8eV (11c).

[0102] In one embodiment of the present invention, the emitter material S B is a TADF material, i.e. one or more TADF emitters. Therefore, in one embodiment of the present invention, the emitter material S B is characterized by its corresponding S1 S and T1 S The energy difference ΔE between ST The value is less than 0.4eV. In a preferred embodiment of the present invention, the emitter material S B is characterized by its ΔE ST The value is less than 0.3eV, less than 0.2eV, less than 0.1eV, or even less than 0.05eV.

[0103] In one embodiment of the present invention, the TADF material E B and emitter material S B All are organic TADF emitters.

[0104] In one embodiment of the present invention, the TADF material E B The lowest excited triplet state energy level T1 E Between 2.2 eV and 3.5 eV, preferably between 2.3 eV and 3.2 eV, more preferably between 2.4 eV and 3.1 eV or even between 2.5 eV and 3.0 eV.

[0105] In one embodiment of the present invention, the lowest unoccupied molecular orbital (LUMO) of the host material B ), the lowest unoccupied molecular orbital LUMO (E B ) and the lowest unoccupied molecular orbital LUMO (S B ) are represented by the following equations (10a) and (10b):

[0106] E LUMO (E B )>E LUMO (S B ) (10a)

[0107] E LUMO (H B )>E LUMO (S B ) (10b).

[0108] In one embodiment of the present invention, the relationship represented by the following formula (10c) holds true:

[0109] E LUMO (H B )>E LUMO (S B ) (10c).

[0110] In one embodiment of the present invention, the relationship expressed by the following formula holds true:

[0111] E LUMO (H B )>E LUMO (E B )>E LUMO (S B ) (10d).

[0112] According to the present invention, the emission layer B comprises at least one host material H B TADF material E B and emitter material S B .

[0113] In a preferred embodiment of the present invention, the light-emitting layer B comprises 39.8-98 wt. %, more preferably 57-93 wt. %, even more preferably 74-87 wt. % of the host compound HB .

[0114] In a preferred embodiment of the present invention, the light-emitting layer B comprises 0.1-50 wt%, more preferably 0.5-40 wt%, even more preferably 1-30 wt% of the TADF material E B .

[0115] In a preferred embodiment of the present invention, the light-emitting layer B comprises 0.1 to 50% by weight, more preferably 0.5 to 40% by weight, even more preferably 1 to 30% by weight of the emitter material S B .

[0116] In a preferred embodiment of the present invention, the emitter material S B is an organic TADF emitter, wherein the light-emitting layer B comprises 1-50 wt. %, more preferably 5-40 wt. %, even more preferably 10-30 wt. % of the emitter material S B .

[0117] In a preferred embodiment of the present invention, the emitter material S B is a NRCT emitter, wherein the light-emitting layer B comprises 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of the emitter material S B .

[0118] In one embodiment of the present invention, the emitter material S B is a fluorescent emitter, wherein the light-emitting layer B comprises 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of the emitter material S B .

[0119] In a preferred embodiment of the present invention, the TADF material E B is an organic TADF emitter, wherein the light-emitting layer B comprises 1-50 wt %, more preferably 5-40 wt %, even more preferably 10-30 wt % of the emitter material E B .

[0120] In a preferred embodiment of the present invention, the TADF material E B is a NRCT emitter, wherein the light-emitting layer B comprises 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of the emitter material E B .

[0121] In a preferred embodiment of the present invention, the light-emitting layer B comprises up to 93% by weight of one or more compounds different from H. B Other main compounds H B2 .

[0122] In a preferred embodiment of the present invention, the emitting layer B comprises up to 93% by weight of one or more solvents.

[0123] In a preferred embodiment of the present invention, the light-emitting layer B comprises (or consists of):

[0124] (i) 39.8-98 wt %, more preferably 57-93 wt %, even more preferably 74-87 wt % of the host compound H B ;

[0125] (ii) 0.1-50 wt%, more preferably 0.5-40 wt%, even more preferably 1-30 wt% of TADF material E B ;and

[0126] (iii) 0.1-50 wt. %, more preferably 0.5-40 wt. %, even more preferably 1-30 wt. % of emitter material S B ;as well as

[0127] (iv) optionally, 0-60 wt% of one or more compounds other than H B Other main compounds H B2 ;and

[0128] (v) Optionally, 0-60 wt% of one or more solvents.

[0129] Preferably, the contents of (i) to (v) total 100% by weight.

[0130] In a preferred embodiment, the emitter material S B and TADF emitter E B are independently a NRCT luminophore, wherein the luminescent layer B comprises (or consists of):

[0131] (i) 39.8-98 wt %, more preferably 57-93 wt %, even more preferably 74-87 wt % of the host compound H B ;

[0132] (ii) 0.1-10 wt%, more preferably 0.5-5 wt%, even more preferably 1-3 wt% of TADF material E B ;and

[0133] (iii) 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of emitter material S B ;as well as

[0134] (iv) optionally, 0-60 wt% of one or more compounds other than H B Other main compounds H B2 ;and

[0135] (v) Optionally, 0-60 wt% of one or more solvents.

[0136] In a preferred embodiment, the emitter material S B It is an organic TADF emitter and the TADF material E B is a NRCT emitter, wherein the light-emitting layer B comprises (or consists of):

[0137] (i) 39.8-98 wt %, more preferably 57-93 wt %, even more preferably 74-87 wt % of the host compound H B ;

[0138] (ii) 0.1-10 wt%, more preferably 0.5-5 wt%, even more preferably 1-3 wt% of TADF material E B ;and

[0139] (iii) 1-50 wt. %, more preferably 5-40 wt. %, even more preferably 10-30 wt. % of emitter material S B ;as well as

[0140] (iv) optionally, 0-59.9 wt% of one or more compounds other than H B Other main compounds H B2 ;and

[0141] (v) Optionally, 0-59.9 wt. % of one or more solvents.

[0142] In a preferred embodiment, the emitter material S B It is a NRCT luminescent material and TADF material E B is an organic TADF emitter, wherein the light-emitting layer B comprises (or consists of):

[0143] (i) 39.8-98 wt %, more preferably 57-93 wt %, even more preferably 74-87 wt % of the host compound H B ;

[0144] (ii) 1-50 wt%, more preferably 5-40 wt%, even more preferably 10-30 wt% of TADF material E B ;and

[0145] (iii) 0.1-10 wt.%, more preferably 0.5-5 wt.%, even more preferably 1-3 wt.% of emitter material S B ;as well as

[0146] (iv) optionally, 0-59.1 wt. % of one or more compounds other than H BOther main compounds H B2 ;and

[0147] (v) Optionally, 0-59.1 wt. % of one or more solvents.

[0148] In a preferred embodiment, the emitter material S B is a fluorescent emitter and the TADF material E B is a NRCT emitter, wherein the light-emitting layer B comprises (or consists of):

[0149] (i) 39.8-98 wt %, more preferably 57-93 wt %, even more preferably 74-87 wt % of the host compound H B ;

[0150] (ii) 0.1-10 wt%, more preferably 0.5-5 wt%, even more preferably 1-3 wt% of TADF material E B ;and

[0151] (iii) 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of emitter material SB; and

[0152] (iv) optionally, 0-60 wt% of one or more compounds other than H B Other main compounds H B2 ;and

[0153] (v) Optionally, 0-60 wt% of one or more solvents.

[0154] In a preferred embodiment, the emitter material S B is a fluorescent emitter and the TADF material E B is an organic TADF emitter, wherein the light-emitting layer B comprises (or consists of):

[0155] (i) 39.8-98 wt%, more preferably 57-93 wt%, even more preferably 74-87 wt% of the host compound H B ;

[0156] (ii) 1-50 wt%, more preferably 5-40 wt%, even more preferably 10-30 wt% of TADF material E B ;and

[0157] (iii) 0.1-10 wt. %, more preferably 0.5-5 wt. %, even more preferably 1-3 wt. % of emitter material S B ;as well as

[0158] (iv) optionally, 0-59.1 wt. % of one or more compounds other than HB Other main compounds H B2 ;and

[0159] (v) Optionally, 0-59.1 wt. % of one or more solvents.

[0160] For example, the host material H B and / or other optional host compounds H B2 It can be selected from CBP (4,4'-bis-(N-carbazolyl)-biphenyl), mCP, mCBP Sif87 (dibenzo[b,d]thiophen-2-yltriphenylsilane), CzSi, Sif88 (dibenzo[b,d]thiophen-2-yl)diphenylsilane), DPEPO (bis[2-(diphenylphosphino)phenyl]ether oxide), 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzothiophenyl-2-yl)phenyl]-9H-carbazole, 9-[3,5-

[0014] Bis(2-dibenzofuranyl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzothiophene)phenyl]-9H-carbazole, T2T(2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine), T3T(2,4,6-tris(triphenyl-3-yl)-1,3,5-triazine) and / or TST(2,4,6-tris(9,9'-spirobifluoren-2-yl)-1,3,5-triazine). In one embodiment of the present invention, the emissive layer B comprises a so-called mixed host system having at least one hole-dominant (n-type) host and one electron-dominant (p-type) host.

[0161] In one embodiment, the light-emitting layer B comprises a first TADF material E B and the second TADF material S B , and a hole-dominated host H B , which is selected from CBP, mCP, mCBP, 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzothiophen-2-yl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzofuranyl)phenyl]-9H-carbazole and 9-[3,5-bis(2-dibenzothiophene)phenyl]-9H-carbazole.

[0162] As used herein, unless more specifically defined in a particular context, the colors of emitted and / or absorbed light are designated as follows:

[0163] Purple: wavelength range >380-420nm;

[0164] Dark blue: wavelength range >420-470nm;

[0165] Sky blue: wavelength range >470-500nm;

[0166] Green: wavelength range >500-560nm;

[0167] Yellow: wavelength range >560-580nm;

[0168] Orange: wavelength range >580-620nm;

[0169] Red: wavelength range >620-800nm.

[0170] For emitter compounds, such colors are the emission maximum λ of a film of poly(methyl methacrylate) (PMMA) with 1-10 wt.% emitter. max PMMA Thus, illustratively, a deep blue emitter has an emission maximum λ in the range 420 to 470 nm. max PMMA , the sky-blue emitter has an emission maximum λ in the range of 470 to 500 nm max PMMA , the green emitter has an emission maximum λ in the range of 500 to 560 nm max PMMA , the red emitter has an emission maximum λ in the range of 620 to 800 nm max PMMA .

[0171] In one embodiment, the TADF material E B The photoluminescence quantum yield PLQY (E B ), emitter material S B The photoluminescence quantum yield PLQY(S B ), wherein, measured in PMMA, PLQY (E B ) and PLQY(S B ) satisfies formula (12).

[0172] PLQY(E B )>PLQY(S B ) (12).

[0173] In a preferred embodiment of the present invention, the organic electroluminescent device exhibits an emission maximum λ of 440 to 560 nm. max (D).

[0174] In a preferred embodiment of the present invention, the organic electroluminescent device exhibits an emission maximum λ of 440 to 470 nm. max (D).

[0175] In a preferred embodiment of the present invention, the organic electroluminescent device exhibits an emission maximum λ of 510 to 550 nm. max (D).

[0176] Near-range-charge-transfer (NRCT) transmitter

[0177] In the context of the present invention, a short-range charge transfer (NRCT) emitter refers to any emitter whose emission spectrum exhibits a full width at half maximum (FWHM) less than or equal to 0.25 eV (≤0.25 eV), measured at room temperature (RT) with 1% by weight of NRCT emitter in PMMA.

[0178] Herein, unless otherwise specified, each spectral characteristic determined herein is determined at room temperature (RT) in PMMA using 1% by weight of the corresponding emitter. Unless otherwise specified, herein, FWHM is measured at room temperature (RT) in PMMA using 1% by weight of the corresponding emitter.

[0179] In a preferred embodiment of the present invention, an NRCT emitter in the context of the present invention is any emitter whose emission spectrum exhibits a FWHM of ≤0.24 eV, more preferably ≤0.23 eV, even more preferably ≤0.22 eV, ≤0.21 eV or ≤0.20 eV, measured at room temperature (RT) using 1 wt% of the NRCT emitter in PMMA. In other embodiments of the present invention, the emitter exhibits a FWHM of ≤0.19 eV, ≤0.18 eV, ≤0.17 eV, ≤0.16 eV, ≤0.15 eV, ≤0.14 eV, ≤0.13 eV, ≤0.12 eV, or ≤0.11 eV.

[0180] A typical NRCT emitter was described by Hatakeyama et al. (Advanced Materials, 2016, 28(14):2777-2781, DOI: 10.1002 / adma.201505491), which showed a delayed component in the time-resolved photoluminescence spectrum and exhibited a close HOMO-LUMO separation.

[0181] Typical NRCT emitters show only one emission band in the emission spectrum, whereas typical fluorescence emitters show several distinct emission bands due to vibrational processes.

[0182] In one embodiment of the present invention, the TADF material E B and / or emitter material S B is a NRCT emitter. In one embodiment of the present invention, the TADF material E Band emitter material S B are all NRCT emitters. In another embodiment of the present invention, the TADF material E B is not an NRCT emitter. In this case, the TADF material E B is an emitter that exhibits TADF properties, but does not exhibit the properties of an NRCT emitter as defined herein. In another embodiment of the present invention, the emitter material S B is not an NRCT emitter. In this case, the emitter material S B is an emitter that does not have the characteristics of an NRCT emitter as defined herein. In one embodiment of the present invention, the emitter material S B It is a fluorescent emitter.

[0183] In one embodiment of the present invention, the emitter material S B is a fluorescent emitter, which is not an NRCT emitter. In another embodiment of the present invention, the TADF material E B and emitter material S B Neither is a NRCT emitter.

[0184] In each context of the present invention, the NRCT emitters may optionally each be boron-containing NRCT emitters, in particular blue boron-containing NRCT emitters.

[0185] In a preferred embodiment, the TADF material E B It is an NRCT emitter.

[0186] In one embodiment, the TADF material E B and / or emitter material S B It is a boron-containing NRCT emitter.

[0187] In one embodiment, the TADF material E B and emitter material S B It is a boron-containing NRCT emitter.

[0188] In a preferred embodiment, the TADF material E B It is a boron-containing NRCT emitter.

[0189] In one embodiment, the TADF material E B It is a blue boron-containing NRCT emitter.

[0190] In a preferred embodiment, the NRCT emitter comprises or consists of a polycyclic aromatic compound. TADF Material E B and / or emitter material S B Contains or consists of polycyclic aromatic compounds.

[0191] In a preferred embodiment, the TADF material E contains 1 wt %. B The film has an emission spectrum with a full width at half maximum (FWHM) of less than 0.2 eV.

[0192] In a preferred embodiment, the TADF material E B It is a boron-containing emitter, the emission spectrum of a film containing 1% by weight of which has a full width at half maximum (FWHM) of less than 0.2 eV.

[0193] In a preferred embodiment, the TADF material E B It is a blue boron-containing emitter with an emission spectrum of less than 0.2 eV full width at half maximum (FWHM) in a 1% by weight film.

[0194] In a preferred embodiment, the TADF material E B The emission spectrum of a film containing or consisting of a polycyclic aromatic compound at a content of 1% by weight has a full width at half maximum (FWHM) of less than 0.2 eV.

[0195] In a preferred embodiment, the TADF material E B A polycyclic aromatic compound comprising (or consisting of) a compound according to formula (1) or (2) or a specific example described in US-A 2015 / 236274. US-A 2015 / 236274 also describes an example of synthesizing such a compound.

[0196] In one embodiment, the TADF material E B Comprising or consisting of a structure according to Formula I:

[0197]

[0198] Where n is 0 or 1.

[0199] m=1-n.

[0200] X 1 It is N or B.

[0201] X 2 It is N or B.

[0202] X 3 It is N or B.

[0203] W is selected from Si(R 3 )2、C(R 3 )2 and BR 3 .

[0204] R 1 、R 2 and R 3Each of which is independently selected from:

[0205] C1-C5 alkyl, which is optionally substituted by one or more substituents R 6 replace;

[0206] C6-C 60 Aryl, which is optionally substituted by one or more substituents R 6 Replacement; and

[0207] C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 6 replace;

[0208] R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI Each independently selected from: hydrogen, deuterium, N(R 5 )2、OR 5 、Si(R 5 ))3、B(OR 5 2. OSO2R 5 , CF3, CN, halogen,

[0209] C1-C 40 Alkyl, which is optionally substituted by one or more substituents R 5 substituted, and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2、Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 )、SO、SO2、NR 5 , O, S, or CONR 5 replace;

[0210] C1-C 40 Alkoxy, which is optionally substituted by one or more substituents R 5 substituted, and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R5 )2、Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0211] C1-C 40 Thioalkoxy, which is optionally substituted by one or more substituents R 5 substituted, and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2、Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0212] C2-C 40 Alkenyl, which is optionally substituted by one or more substituents R 5 substituted, and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2、Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0213] C2-C 40 Alkynyl, which is optionally substituted by one or more substituents R 5 substituted, and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2、Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5, O, S, or CONR 5 replace;

[0214] C6-C 60 Aryl, which is optionally substituted by one or more substituents R 5 Replacement; and

[0215] C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 5 replace.

[0216] R 5 is independently selected at each occurrence from the group consisting of hydrogen, deuterium, OPh, CF3, CN, F,

[0217] C1-C5 alkyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0218] C1-C5 alkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0219] C1-C5 thioalkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0220] C2-C5 alkenyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0221] C2-C5 alkynyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0222] C6-C 18 aryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0223] C3-C 17 heteroaryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0224] N(C6-C 18 aryl)2,

[0225] N(C3-C 17 heteroaryl)2; and

[0226] N(C3-C 17 Heteroaryl)(C6-C 18 aryl).

[0227] R 6 is independently selected at each occurrence from hydrogen, deuterium, OPh, CF3, CN, F,

[0228] C1-C5 alkyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0229] C1-C5 alkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0230] C1-C5 thioalkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0231] C2-C5 alkenyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0232] C2-C5 alkynyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F;

[0233] C6-C 18 aryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0234] C3-C 17 heteroaryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0235] N(C6-C 18 Aryl)2;

[0236] N(C3-C 17 heteroaryl)2; and

[0237] N(C3-C 17 Heteroaryl)(C6-C 18 aryl).

[0238] According to a preferred embodiment, two or more adjacent I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI The substituents may each form a monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring system with each other.

[0239] According to a preferred embodiment, X 1 、X 2 and X 3 At least one of them is B, X 1 、X 2 and X 3At least one of them is N.

[0240] According to a preferred embodiment of the present invention, at least one selected from R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI The substituents optionally form a monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring system with one or more adjacent substituents of the same group.

[0241] According to a preferred embodiment of the present invention, X 1 、X 2 and X 3 At least one of them is B, and X 1 、X 2 and X 3 At least one of them is N.

[0242] In one embodiment, the TADF material E B Comprising (or consisting of) a structure according to Formula 1 and n=0.

[0243] In one embodiment, R 1 and R 2 Each independently selected from the following group:

[0244] C1-C5 alkyl, which is optionally substituted by one or more substituents R 6 replace;

[0245] C6-C 30 Aryl, which is optionally substituted by one or more substituents R 6 Replacement; and

[0246] C3-C 30 Heteroaryl, which is optionally substituted by one or more substituents R 6 replace.

[0247] In one embodiment, R 1 and R 2 Each independently selected from Me, i Pr, t Bu, CN, CF3,

[0248] Ph, which is optionally selected from one or more independently of each other Me, i Pr, tBu, CN, CF3 and Ph; pyridyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0249] pyrimidinyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution with Bu, CN, CF3 and Ph; and

[0250] triazine radicals, which are optionally substituted by one or more independently selected from Me, i Pr, t Substitution with Bu, CN, CF3 and Ph.

[0251] In one embodiment, R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI Each of is independently selected from: hydrogen, deuterium, halogen, Me, i Pr, t Bu,CN,CF3,

[0252] Ph, which is optionally selected from one or more independently of each other, Me, i Pr, t Bu, CN, CF3 and Ph; pyridyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0253] pyrimidinyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0254] Carbazolyl, which is optionally replaced by one or more independently selected from Me, i Pr, t Substitution by substituents from the group consisting of Bu, CN, CF3 and Ph;

[0255] triazine radicals, which are optionally substituted by one or more independently selected from Me, i Pr, tSubstitution with Bu, CN, CF3 and Ph; and

[0256] N(Ph)2.

[0257] In one embodiment, R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI Each of is independently selected from: hydrogen, deuterium, halogen, Me, i Pr, t Bu,CN,CF3,

[0258] Ph, which is optionally selected from one or more independently of each other Me, i Pr, t Bu, CN, CF3 and Ph; pyridyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0259] pyrimidinyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0260] Carbazolyl, which is optionally replaced by one or more independently selected from Me, i Pr, t Substitution by substituents from the group consisting of Bu, CN, CF3 and Ph;

[0261] triazine radicals, which are optionally substituted by one or more independently selected from Me, i Pr, t Substitution with Bu, CN, CF3 and Ph; and

[0262] N(Ph)2; and

[0263] R 1 and R 2 Each independently selected from the following group:

[0264] C1-C5 alkyl, which is optionally substituted by one or more substituents R 6 replace;

[0265] C6-C 30 Aryl, which is optionally substituted by one or more substituents R6 Replacement; and

[0266] C3-C 30 Heteroaryl, which is optionally substituted by one or more substituents R 6 replace.

[0267] In one embodiment of the present invention, the emitter material S B It is a short-range charge transfer (NRCT) emitter. According to the present invention, the NRCT material exhibits a delayed component in the time-resolved photoluminescence spectrum and exhibits short-range HOMO-LUMO separation as described by Hatakeyama et al. (Advanced Materials, 2016, 28(14):2777-2781, DOI: 10.1002 / adma.201505491).

[0268] In one embodiment, the emitter material S B It is a boron-containing NRCT emitter.

[0269] In one embodiment, the emitter material S B It is a blue boron-containing NRCT emitter.

[0270] In a preferred embodiment, the emitter material S B Contains or consists of polycyclic aromatic compounds.

[0271] In a preferred embodiment, the emitter material S is contained in an amount of 1% by weight. B The emission spectrum of the film has a full width at half maximum (FWHM) of less than 0.2 eV.

[0272] In a preferred embodiment, the emitter material S B is a boron-containing emitter whose emission spectrum of a 1 wt% thin film has a full width at half maximum (FWHM) of less than 0.2 eV.

[0273] In a preferred embodiment, the emitter material S B It is a blue boron-containing emitter whose emission spectrum of a 1 wt% thin film has a full width at half maximum (FWHM) of less than 0.2 eV.

[0274] In a preferred embodiment, the emitter material S B The emission spectrum of a thin film comprising or consisting of a polycyclic aromatic compound at 1 wt. % thereof has a full width at half maximum (FWHM) of less than 0.2 eV.

[0275] In a preferred embodiment, the emitter material S BThe invention comprises or consists of a polycyclic aromatic compound according to formula (1) or (2) or a specific example described in US-A 2015 / 236274. US-A 2015 / 236274 also describes an example of the synthesis of such a compound.

[0276] In one embodiment, the emitter material S B Comprising or consisting of a structure according to Formula I.

[0277] In one embodiment, the TADF material E B and / or emitter material S B is a blue boron-containing NRCT emitter selected from the group consisting of:

[0278]

[0279]

[0280]

[0281]

[0282]

[0283] In one embodiment, the TADF material E B and / or emitter material S B is a green boron-containing NRCT emitter selected from the group consisting of:

[0284]

[0285] Organic TADF emitters

[0286] In a preferred embodiment, the TADF material E B and / or emitter material S B It is an organic TADF material. According to the present invention, an organic emitter or organic material refers to an emitter or material (predominantly) composed of the elements hydrogen (H), carbon (C), nitrogen (N), boron (B), silicon (Si), and optionally fluorine (F), optionally bromine (Br), and optionally oxygen (O). Particularly preferably, it does not contain any transition metals.

[0287] In a preferred embodiment, the TADF material E B is an organic TADF material. In a preferred embodiment, the emitter material S B In a more preferred embodiment, the TADF material E B and emitter material S B They are all organic TADF materials.

[0288] In a preferred embodiment, the TADF material E B and / or emitter material S B is an organic TADF material selected from molecules having the structure of formula I-TADF

[0289]

[0290] in

[0291] o is 1 or 2 independently on each occurrence;

[0292] p is 1 or 2 independently at each occurrence;

[0293] X is independently Ar at each occurrence EWG , H, CN or CF3;

[0294] Z is independently selected at each occurrence from a direct bond, CR 3 R 4 、C=CR 3 R 4 、C=O、C=NR 3 NR 3 、O、SiR 3 R 4 , S, S(O) and S(O)2;

[0295] Ar EWG is, independently of one another, a structure according to one of the formulae IIa to IIk

[0296]

[0297]

[0298] Where # represents the binding site of the single bond, which EWG connected to a substituted central benzene ring of formula I-TADF;

[0299] R 1 independently selected at each occurrence from hydrogen, deuterium, C1-C5 alkyl and C6-C 18 Aryl, wherein one or more hydrogen atoms of the C1-C5 alkyl group are optionally substituted with deuterium, and the C6-C 18 The aryl group is optionally substituted by one or more substituents R 6 replace;

[0300] R 2 independently selected at each occurrence from hydrogen, deuterium, C1-C5 alkyl and C6-C 18 Aryl, wherein one or more hydrogen atoms of the C1-C5 alkyl group are optionally substituted with deuterium, and the C6-C 18The aryl group is optionally substituted by one or more substituents R 6 replace;

[0301] R a 、R 3 and R 4 is independently selected at each occurrence from hydrogen, deuterium, N(R 5 )2、OR 5 、

[0302] SR 5 、Si(R 5 )3、CF3、CN、F、

[0303] C1-C 40 Alkyl, which is optionally substituted by one or more substituents R 5 substituted, and one or more non-adjacent CH2- groups are optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2, Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0304] C1-C 40 Thioalkoxy, which is optionally substituted by one or more substituents R 5 substituted, and one or more non-adjacent CH2- groups are optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2,Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0305] C6-C 60 Aryl, which is optionally substituted by one or more substituents R 5 Replacement; and

[0306] C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 5 replace;

[0307] R 5is independently selected at each occurrence from hydrogen, deuterium, N(R 6 )2、OR 6 SR 6 、Si(R 6 )3、CF3、CN、F、C1-C 40 Alkyl, which is optionally substituted by one or more substituents R 6 substituted, and one or more non-adjacent CH2- groups are optionally replaced by R 6 C=CR 6 、C≡C、Si(R 6 )2、Ge(R 6 )2, Sn(R 6 )2. C=O, C=S, C=Se, C=NR 6 、P(=O)(R 6 )、SO、SO2、NR 6 , O, S, or CONR 6 replace;

[0308] C6-C 60 Aryl, which is optionally substituted by one or more substituents R 6 Replacement; and

[0309] C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 6 replace;

[0310] R 6 is independently selected at each occurrence from hydrogen, deuterium, OPh, CF3, CN, F,

[0311] C1-C5 alkyl, wherein one or more hydrogen atoms are optionally substituted independently of one another by deuterium, CN, CF3 or F;

[0312] C1-C5 alkoxy, wherein one or more hydrogen atoms are optionally substituted independently of one another by deuterium, CN, CF3 or F;

[0313] C1-C5 thioalkoxy, wherein one or more hydrogen atoms are optionally substituted independently of one another by deuterium, CN, CF3 or F;

[0314] C6-C 18 aryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0315] C3-C 17 heteroaryl, which is optionally substituted with one or more C1-C5 alkyl substituents;

[0316] N(C6-C 18 Aryl)2;

[0317] N(C3-C 17 heteroaryl)2, and

[0318] N(C3-C 17 Heteroaryl)(C6-C 18 aryl);

[0319] R d is independently selected at each occurrence from hydrogen, deuterium, N(R 5 )2、OR 5 、

[0320] SR 5 、Si(R 5 )3、CF3、CN、F、

[0321] C1-C 40 Alkyl, which is optionally substituted by one or more substituents R 5 and wherein one or more non-adjacent CH2- groups are optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2,Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 replace;

[0322] C1-C 40 Thioalkoxy, which is optionally substituted by one or more substituents R 5 substituted, wherein one or more non-adjacent CH2-groups are optionally replaced by R 5 C=CR 5 、C≡C、Si(R 5 )2、Ge(R 5 )2,Sn(R 5 )2. C=O, C=S, C=Se, C=NR 5 、P(=O)(R 5 ), SO, SO2, NR 5 , O, S, or CONR 5 Replacement; and

[0323] C6-C 60 Aryl, which is optionally substituted by one or more substituents R 5 Replacement; C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 5 replace;

[0324] The substituent R a 、R 3 、R 4 or R 5 Independently of each other, optionally with one or more substituents R a 、R 3 、R 4 or R 5 forming a monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring system, and wherein the one or more substituents R d Independently of each other, optionally with one or more substituents R d Mono- or polycyclic, aliphatic, aromatic and / or benzo-fused ring systems are formed.

[0325] According to the present invention, the substituent R a 、R 3 、R 4 or R 5 In each case, independently of one another, one or more substituents R a 、R 3 、R 4 or R 5 Forming monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring systems.

[0326] According to the present invention, the substituent R d In each case, independently of one another, they may optionally be combined with one or more other substituents R d Monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring systems are formed.

[0327] In a particularly preferred embodiment of the present invention, Z is a direct bond at each occurrence.

[0328] In a preferred embodiment, the TADF material E B is an organic TADF material selected from molecules having the structure of formula I-TADF.

[0329] In one embodiment of the present invention, the TADF material E B Contains at least one triazine structure according to formula IIa.

[0330] In a preferred embodiment, the TADF material E B is an organic TADF material selected from molecules having the structure of formula II-TADF

[0331]

[0332] In one embodiment of the present invention, R a are independently selected at each occurrence from hydrogen, deuterium, Me, iPr, t Bu, CN, CF3,

[0333] Ph, which is optionally selected from one or more independently of each other by Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0334] Pyridyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0335] pyrimidinyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0336] Carbazolyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0337] triazine radicals, which are optionally substituted by one or more independently selected from Me, i Pr, t Substitution with Bu, CN, CF3 and Ph; and N(Ph)2.

[0338] In one embodiment of the present invention, R d are independently selected at each occurrence from hydrogen, deuterium, Me, i Pr, t Bu, CN, CF3,

[0339] Ph, which is optionally selected from one or more independently of each other by Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0340] Pyridyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0341] pyrimidinyl, which is optionally substituted by one or more independently selected from Me, i Pr, t Substitution of Bu, CN, CF3 and Ph;

[0342] Carbazolyl, which is optionally substituted by one or more independently selected from Me, i Pr, tSubstitution of Bu, CN, CF3 and Ph;

[0343] triazine radicals, which are optionally substituted by one or more independently selected from Me, i Pr, t Substitution with Bu, CN, CF3 and Ph; and N(Ph)2.

[0344] In a preferred embodiment, X is CN.

[0345] In one embodiment of the present invention, the TADF material E B Selected from the structure of formula III

[0346]

[0347] where R a , X and R 1 As defined above.

[0348] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IIIa:

[0349]

[0350] where R a , X and R 1 As defined above.

[0351] In one embodiment of the present invention, E B Selected from molecules having the structure of formula IIIa-1:

[0352]

[0353] where R a , X and R 1 As defined above.

[0354] In one embodiment of the present invention, E B Selected from molecules having the structure of formula IIIa-2:

[0355]

[0356] where R a , X and R 1 As defined above.

[0357] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IIIb:

[0358]

[0359] where Ra and R 1 As defined above.

[0360] In one embodiment of the present invention, E B Selected from molecules having the structure of formula IIIa-1:

[0361]

[0362] where R a and R 1 As defined above.

[0363] In one embodiment of the present invention, E B Selected from molecules having the structure of formula IIIc:

[0364] (Formula IIIc),

[0365] where R a and R 1 As defined above.

[0366] In one embodiment of the present invention, E B Selected from molecules having the structure of formula IIId:

[0367]

[0368] where R a and R 1 As defined above.

[0369] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IV:

[0370]

[0371] where R a 、R 1 and X are as defined above.

[0372] In one embodiment of the present invention, E B A molecule selected from the structure of formula IVa:

[0373]

[0374] where R a 、R 1 and X are as defined above.

[0375] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IVb:

[0376]

[0377] where R a and R 1 As defined above.

[0378] In one embodiment of the present invention, E B Selected from molecules having the structure of formula V:

[0379]

[0380] where R a 、R 1 and X are as defined above.

[0381] In one embodiment of the present invention, E B Selected from molecules having the structure of formula Va:

[0382]

[0383] where R a 、R 1 and X are as defined above.

[0384] In one embodiment of the present invention, E B Selected from molecules having the structure of formula Vb:

[0385]

[0386] where R a and R 1 As defined above.

[0387] In one embodiment of the present invention, E B Selected from molecules having the structure of formula VI:

[0388]

[0389] where R a 、R 1 and X are as defined above.

[0390] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula VIa:

[0391]

[0392] where R a 、R 1 and X are as defined above.

[0393] In one embodiment of the present invention, E B A molecule selected from the group consisting of:

[0394]

[0395] where R a and R 1 As defined above.

[0396] In one embodiment of the present invention, E B Selected from molecules having the structure of formula VII:

[0397]

[0398] where R a and X is defined as above.

[0399] In one embodiment of the present invention, E B A molecule selected from the structure of formula VIIa:

[0400]

[0401] where R a and X is defined as above.

[0402] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula VIIb:

[0403]

[0404] where R a As defined above.

[0405] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula VIII:

[0406]

[0407] where R a and X is defined as above.

[0408] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula VIIIa:

[0409]

[0410] where R a and X is defined as above.

[0411] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula VIIIb:

[0412]

[0413] where R a As defined above.

[0414] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IX:

[0415]

[0416] where R a and X is defined as above.

[0417] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IXa:

[0418]

[0419] where R a and X is defined as above.

[0420] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula IXb:

[0421]

[0422] where R a As defined above.

[0423] In one embodiment of the present invention, E B Selected from molecules having the structure of formula X:

[0424]

[0425] where R a and X is defined as above.

[0426] In one embodiment of the present invention, E B Selected from molecules having the structure of formula Xa:

[0427]

[0428] where R a and X is defined as above.

[0429] In one embodiment of the present invention, E B Selected from molecules having the structure of formula Xb:

[0430]

[0431] where R a As defined above.

[0432] In one embodiment of the present invention, E B Selected from molecules having the structure of formula XI:

[0433]

[0434] where R a and X is defined as above.

[0435] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula XIa:

[0436]

[0437] where R a and X is defined as above.

[0438] In one embodiment of the present invention, E B Selected from molecules having the structure of formula XIb:

[0439]

[0440] where R a As defined above.

[0441] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula XII:

[0442]

[0443] where R a , X and R d As defined above.

[0444] In one embodiment of the present invention, E B A molecule selected from the structure of formula XIIa:

[0445]

[0446] where R a , X and R d As defined above.

[0447] In one embodiment of the present invention, E B Selected from molecules having the structure of Formula XIIb:

[0448]

[0449] where R a , X and R d As defined above.

[0450] The synthesis of molecules having the structure of formula I-TADF can be accomplished by standard reactions and reaction conditions known to those skilled in the art. Typically, a coupling reaction is performed in the first step, preferably a palladium-catalyzed coupling reaction.

[0451]

[0452] E1 can be any boric acid (R B =H) or the corresponding borate ester (R B =alkyl or aryl), especially two R B To form a ring, for example, fluoro-(trifluoromethyl)phenyl, difluoro-(trifluoromethyl)phenyl, fluoro-(cyano)phenyl or difluoro-(cyano)phenyl boronic acid pinacol esters. As the second reactant E2, preferably Ar EWG The reaction conditions of this palladium-catalyzed coupling reaction are known to those skilled in the art, for example, see WO 2017 / 005699, and it is known that the reactive groups of E1 and E2 can be interchanged to optimize the reaction yield.

[0453]

[0454] In the second step, the molecule according to formula I-TADF is obtained by reaction of the nitrogen heterocycle in the nucleophilic aromatic substitution with an aryl halide (preferably an aryl fluoride or an aryl dihalide, preferably an aryl difluoride) E3. Typical conditions include the use of a base such as tripotassium phosphate or sodium hydride in an aprotic polar solvent such as dimethyl sulfoxide (DMSO) or N,N-dimethylformamide (DMF).

[0455]

[0456] In particular, the donor molecule E6 is a 3,6-substituted carbazole (e.g., 3,6-dimethylcarbazole, 3,6-diphenylcarbazole, 3,6-di-tert-butylcarbazole), a 2,7-substituted carbazole (e.g., 2,7-dimethylcarbazole, 2,7-diphenylcarbazole, 2,7-di-tert-butylcarbazole), a 1,8-substituted carbazole (e.g., 1,8-dimethylcarbazole, 1,8-diphenylcarbazole, 1,8-di-tert-butylcarbazole), a 1-substituted carbazole (e.g., 1-methylcarbazole, 1-phenylcarbazole, 1-tert-butylcarbazole), a 2-substituted carbazole (e.g., 2-methylcarbazole, 2-phenylcarbazole, 2-tert-butylcarbazole), or a 3-substituted carbazole (e.g., 3-methylcarbazole, 3-phenylcarbazole, 3-tert-butylcarbazole). Alternatively, a halogen-substituted carbazole, in particular 3-bromocarbazole, can be used as E6.

[0457] In the subsequent reaction, illustratively, a boronate functional group or a boronic acid functional group can be introduced into the position of one or more halogen substituents introduced by E6 to produce the corresponding carbazole-3-yl boronate or carbazole-3-yl boronic acid, for example, by reacting with bis(pinacolato)diboron (CAS No. 73183-34-3). Subsequently, the corresponding halogenated reactant R a- Hal, preferably R a Cl and R a The coupling reaction of Br introduces one or more substituents R a Alternatively, the boronic acid group can be replaced by a boronic acid ester group or a boronic acid group. a [R a B (OH) 2] boronic acid or the corresponding boric acid ester to introduce one or more substituents R at the position of one or more halogen substituents introduced by DH a .

[0458] Another synthetic route involves the introduction of the nitrogen heterocycle into an aryl halide or aryl pseudohalide, preferably an aryl bromide, aryl iodide, aryl triflate or aryl tosylate, by copper or palladium catalyzed coupling.

[0459] Emitter material S B A device that emits blue fluorescent light

[0460] In one embodiment of the present invention, the emitter material S B It is a fluorescent emitter, especially a blue fluorescent emitter.

[0461] In one embodiment, the emitter material S B is a blue fluorescent emitter selected from the group consisting of:

[0462]

[0463]

[0464]

[0465]

[0466]

[0467]

[0468]

[0469]

[0470] In certain embodiments, the emitter material S Bis a blue fluorescent emitter selected from the group consisting of:

[0471]

[0472] Emitter material S B It is a triplet-triplet annihilation (TTA) fluorescence emitter device.

[0473] In one embodiment of the present invention, the emitter material S B It is a triplet-triplet annihilation (TTA) emitter.

[0474] In one embodiment, S B is a blue TTA emitter selected from the following group:

[0475]

[0476] Emitter material S B Green fluorescent emitter device

[0477] In another embodiment of the present invention, the emitter material S B It is a fluorescent emitter, especially a green fluorescent emitter.

[0478] In one embodiment, the emitter material S B is a fluorescent emitter selected from the group consisting of:

[0479]

[0480] In another embodiment of the present invention, the device has an emission peak in the visible or ultraviolet range, i.e. in the wavelength range of 380 to 800 nm, in particular between 485 nm and 590 nm, preferably between 505 nm and 565 nm, even more preferably between 515 nm and 545 nm.

[0481] Emitter material S B A device that emits red fluorescent light

[0482] In another embodiment of the present invention, the emitter material S B It is a fluorescent emitter, especially a red fluorescent emitter.

[0483] In one embodiment, the emitter material S B is a fluorescent emitter selected from the group consisting of:

[0484]

[0485]

[0486]

[0487] In another embodiment of the present invention, the device has an emission peak in the visible or ultraviolet range, i.e. in the wavelength range of 380 to 800 nm, in particular between 590 nm and 690 nm, preferably between 610 nm and 665 nm, even more preferably between 620 nm and 640 nm.

[0488] Orbital and excited state energies can be determined experimentally by methods known to those skilled in the art. Experimentally, the highest occupied molecular orbital E HOMO The energy of is determined from cyclic voltammetry measurements with an accuracy of 0.1 eV by methods known to those skilled in the art. LUMO The energy is E HOMO +E gap , where E gap Determine as follows:

[0489] For host compounds, unless otherwise stated, the onset of emission of a 10 wt% thin film of the host compound in polymethyl methacrylate (PMMA) is given as E gap For emitter compounds, such as NRCT emitters and fluorescent emitters, unless otherwise stated, the energy at which the excitation and emission spectra of a 10 wt% film of the emitter in polymethyl methacrylate (PMMA) intersect is taken as E gap For organic TADF emitters, unless otherwise stated, the energy at which the excitation and emission spectra of a 10 wt% film of emitter in polymethyl methacrylate (PMMA) intersect is taken as E gap .

[0490] For the host compounds, unless otherwise stated, the onset of emission from a 10 wt% polymethyl methacrylate (PMMA) film thereof, corresponding to the energy of the first excited singlet state S1, was used as E gap For emitter compounds, such as NRCT emitters and fluorescent emitters, E is determined in the same manner unless otherwise stated. gap and the energy of the first excited singlet state S1. For organic TADF emitters, unless otherwise stated, the onset of emission from a 10 wt% polymethyl methacrylate (PMMA) film, corresponding to the energy of the first excited singlet state S1, is used as E gap .

[0491] For host compounds, unless otherwise stated, the energy of the first excited triplet state, T1, is determined from the onset of time-gated emission spectroscopy at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms, measured on a 10 wt% polymethyl methacrylate (PMMA) film. For emitter compounds, such as NRCT emitters and fluorescent emitters, the energy of the first excited triplet state, T1, is determined from the onset of time-gated emission spectroscopy at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms, or, if not otherwise stated, on a 1 wt% polymethyl methacrylate (PMMA) film. For organic TADF emitters, the energy of the first excited triplet state, T1, is determined from the onset of time-gated emission spectroscopy at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms, or, if not otherwise stated, on a 10 wt% polymethyl methacrylate (PMMA) film. For TADF compounds, the energy of the first excited triplet state, T1, is determined from the onset of time-gated emission spectroscopy at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms.

[0492] In the electron transport layer (ETL), any electron transport agent can be used. For example, electron-deficient compounds such as benzimidazole, pyridine, triazole, oxadiazole (e.g., 1,3,4-oxadiazole), phosphine oxide and sulfone. For example, the electron transporter ETMD can also be a star-shaped heterocycle, such as 1,3,5-tris(1-phenyl-1 H -benzo[d]imidazol-2-yl)phenyl (TPBi). For example, ETMD can be NBphen (2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline), Alq3 (aluminum-tris(8-hydroxyquinoline)), TSPO1 (diphenyl-4-triphenylsilylphenylphosphine oxide), BPyTP2 (2,7-bis(2,2'-bipyridin-5-yl)biphenyl),

[0493] Sif87 (dibenzo[b,d]thiophen-2-yltriphenylsilane), Sif88 (dibenzo[b,d]thiophen-2-yl)diphenylsilane),

[0494] BmPyPhB (1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene) and / or

[0495] BTB (4,4'-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1'-biphenyl). Optionally, the electron transport layer can be doped with a material such as Liq (lithium 8-hydroxyquinolinolate). Optionally, a second electron transport layer can be located between the electron transport layer and the cathode layer C.

[0496] Adjacent to the electron transport layer (ETL), a cathode layer C may be provided. Exemplarily, the cathode layer C may comprise (or be composed of) a metal (e.g., Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, LiF, Ca, Ba, Mg, In, W, or Pd) or a metal alloy. For practical reasons, the cathode layer C may also be composed of (substantially) opaque metals such as Mg, Ca, or Al. Alternatively or additionally, the cathode layer C may also comprise graphite and / or carbon nanotubes (CNTs). Alternatively, the cathode layer C may also be composed of nanoscale silver wires.

[0497] The OLED may also optionally include a protective layer located between the electron transport layer (ETL) D and the cathode layer C (which may be referred to as an electron injection layer (EIL)). This layer may contain lithium fluoride, cesium fluoride, silver, Liq (lithium 8-hydroxyquinolinolate), Li2O, BaF2, MgO, and / or NaF.

[0498] Therefore, another embodiment of the present invention relates to an OLED having a brightness of 1000 cd / m 2 The invention further comprises a photoconductive material having an external quantum efficiency of greater than 10%, more preferably greater than 12%, more preferably greater than 15%, even more preferably greater than 17% or even greater than 20% under the conditions of 100 nm to 200 nm, and / or an emission maximum nm between 490 nm and 570 nm, preferably between 500 nm and 560 nm, more preferably between 510 nm and 550 nm, even more preferably between 520 nm and 540 nm, and / or an emission maximum nm between 500 cd / m 2 The LT80 value under the conditions described above is more than 3000 hours, preferably more than 6000 hours, more preferably more than 12000 hours, even more preferably more than 22500 hours or even more than 30000 hours.

[0499] Therefore, another embodiment of the present invention relates to an OLED having a brightness of 1000 cd / m 2 The optical fiber exhibits an external quantum efficiency of greater than 10%, more preferably greater than 12%, more preferably greater than 15%, even more preferably greater than 17% or even greater than 20% at room temperature, and / or exhibits an emission maximum between 420 nm and 500 nm, preferably between 430 nm and 490 nm, more preferably between 440 nm and 480 nm, even more preferably between 450 nm and 470 nm, and / or an optical fiber exhibiting an optical fiber at 500 cd / m 2 The LT80 value under the conditions described above is more than 100 hours, preferably more than 200 hours, more preferably more than 400 hours, even more preferably more than 750 hours or even more than 1000 hours.

[0500] Another embodiment of the present invention relates to an OLED that emits light at a specific color point. According to the present invention, the OLED emits light with a narrow emission band (i.e., a small full width at half maximum (FWHM)). In a preferred embodiment, the FWHM of the main emission peak of the light emitted by the OLED according to the present invention is less than 0.43 eV, more preferably less than 0.39 eV, even more preferably less than 0.35 eV, or even less than 0.31 eV.

[0501] In a particularly preferred embodiment, the emitter material S B The OLED which is a NRCT emitter and which emits light according to the invention has a main emission peak with a FWHM below 0.25 eV, more preferably below 0.23 eV, even more preferably below 0.21 eV, even below 0.20 eV.

[0502] Another embodiment of the present invention relates to an OLED having CIEx (=0.131) and CIEy (=0.046) color coordinates of the emitted light close to the CIEx (=0.131) and CIEy (=0.046) color coordinates of the primary color blue, as defined in ITU-R Recommendation BT.2020 (Rec.2020), and is therefore suitable for ultra-high-definition (UHD) displays, such as ultra-high-definition televisions. In commercial applications, top-emitting (top electrode is transparent) devices are typically used, while the test devices used throughout this application are bottom-emitting devices (bottom electrode and substrate are transparent). When changing from a bottom-emitting device to a top-emitting device, the CIEy color coordinates of the blue device can be reduced by up to two times, while the CIEx remains almost unchanged (see Okinaka et al. doi:10.1002 / sdtp.10480). Therefore, another embodiment of the present invention relates to an OLED, the CIEx color coordinates of which the emission is between 0.02 and 0.30, preferably between 0.03 and 0.25, more preferably between 0.05 and 0.20, or even more preferably between 0.08 and 0.18, or even between 0.10 and 0.15, and / or the CIEy color coordinates of which the emission is between 0.00 and 0.45, preferably between 0.01 and 0.30, more preferably between 0.02 and 0.20 or even more preferably between 0.03 and 0.15 or even between 0.04 and 0.10.

[0503] Another embodiment of the present invention relates to an OLED having CIEx (=0.170) and CIEy (=0.797) color coordinates of the emitted light close to the CIEx (=0.170) and CIEy (=0.797) color coordinates of the primary color green, as defined in ITU-R Recommendation BT.2020 (Rec.2020), and is therefore suitable for ultra-high-definition (UHD) displays, such as ultra-high-definition televisions. In this context, the term "close" refers to the range of CIEx and CIEy coordinates provided at the end of this paragraph. In commercial applications, top-emitting (top electrode is transparent) devices are typically used, while the test devices used throughout this application are bottom-emitting devices (bottom electrode and substrate are transparent). When changing from a bottom-emitting device to a top-emitting device, the CIEy color coordinates of the blue device can be reduced by up to two times, while the CIEx remains almost unchanged (see Okinaka et al. doi:10.1002 / sdtp.10480). Therefore, another embodiment of the present invention relates to an OLED, the emission of which has a CIEx color coordinate of between 0.06 and 0.34, preferably between 0.07 and 0.29, more preferably between 0.09 and 0.24, or even more preferably between 0.12 and 0.22, or even between 0.14 and 0.19, and / or the emission of which has a CIEy color coordinate of between 0.75 and 1.20, preferably between 0.76 and 1.05, more preferably between 0.77 and 0.95 or even more preferably between 0.78 and 0.90, or even between 0.79 and 0.85.

[0504] Another embodiment of the present invention relates to an OLED having CIEx (= 0.708) and CIEy (= 0.292) color coordinates of the emitted light close to the CIEx (= 0.708) and CIEy (= 0.292) color coordinates of the primary color red, as defined in ITU-R Recommendation BT.2020 (Rec.2020), and is therefore suitable for ultra-high-definition (UHD) displays, such as ultra-high-definition televisions. In this context, the term "close" refers to the range of CIEx and CIEy coordinates provided at the end of this paragraph. In commercial applications, top-emitting (top electrode is transparent) devices are typically used, while the test devices used throughout this application are bottom-emitting devices (bottom electrode and substrate are transparent). When changing from a bottom-emitting device to a top-emitting device, the CIEy color coordinates of the blue device can be reduced by up to two times, while the CIEx remains almost unchanged (see Okinaka et al. doi: 10.1002 / sdtp.10480). Therefore, another embodiment of the present invention relates to an OLED whose emission has a CIEx color coordinate of between 0.60 and 0.88, preferably between 0.61 and 0.83, more preferably between 0.63 and 0.78, or even more preferably between 0.66 and 0.76, or even between 0.68 and 0.73, and / or whose emission has a CIEy color coordinate of between 0.25 and 0.70, preferably between 0.26 and 0.55, more preferably between 0.27 and 0.45 or even more preferably between 0.28 and 0.40, or even between 0.29 and 0.35.

[0505] In this application, the terms "aryl" and "aromatic" can be understood in the broadest sense to mean any monocyclic, bicyclic or polycyclic aromatic moieties. If not otherwise specified, an aryl group can also be optionally substituted with one or more substituents, which are further illustrated in this application. Thus, the term "arylene" refers to a divalent residue that has two sites for binding to other molecular structures and thus serves as a linker structure. In this application, the terms "heteroaryl" and "heteroaromatic" can be understood in the broadest sense to mean any monocyclic, bicyclic or polycyclic heteroaromatic moieties comprising at least one heteroatom, particularly any monocyclic, bicyclic or polycyclic heteroaromatic moiety having 1-3 heteroatoms per aromatic ring. Exemplarily, heteroaromatic compounds can be selected from pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine and pyrimidine, etc. If not otherwise specified, a heteroaryl group can also be optionally substituted with one or more substituents, which are further illustrated in this application. Therefore, the term "heteroarylene" refers to a divalent residue that has two sites for binding to other molecular structures and is therefore used as a linker structure. In the present application, the term "alkyl" can be understood in the broadest sense as a straight or branched chain alkyl residue. Preferred alkyl residues contain 1-15 carbon atoms. Illustratively, the alkyl residue can be a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, etc. If not otherwise specified, the alkyl group can also be optionally substituted with one or more substituents, which are further illustrated in the present application. Therefore, the term "alkylene" refers to a divalent residue that has two sites for binding to other molecular structures and is therefore used as a linker structure.

[0506] If not otherwise stated, in this application, in particular in the context of aryl, arylene, heteroaryl, alkyl etc., the term "substituted" is to be understood in the broadest sense. Preferably, such substitution refers to a substituted group selected from C1-C 20 Alkyl, C7-C 19 Alkaryl and C6-C 18 Thus, preferably, no charged moieties, more preferably no functional groups, are present in such substitutions.

[0507] It is worth noting that in each occurrence, hydrogen can be replaced by deuterium.

[0508] Unless otherwise stated, any layer of the various embodiments can be deposited by any suitable method. The layers of the present invention, including the light-emitting layer B, can optionally be prepared by liquid processing (also known as "thin film processing", "fluid processing", "solution processing" or "solvent processing"). This means that the components contained in the corresponding layer are applied to the surface of a portion of the device in a liquid state. Preferably, the layers of the present invention, including the light-emitting layer B, can be prepared by spin coating. This method, which is well known to those skilled in the art, can obtain thin and (substantially) uniform layers.

[0509] Alternatively, the layers of the present invention, including the light-emitting layer B, can be prepared by other methods based on liquid processing, such as casting (e.g., drop casting) and rolling methods, and printing methods (e.g., inkjet printing, gravure printing, doctor blade coating). This can optionally be carried out in an inert atmosphere (e.g., in nitrogen).

[0510] In another preferred embodiment, the layer of the present invention can be prepared by any other method known in the art, including but not limited to vacuum processing methods well known to those skilled in the art, such as thermal (co)evaporation, organic vapor phase deposition (OVPD) and organic vapor phase jet printing (OVJP) deposition.

[0511] When a liquid processing process is used to prepare the layer, the layer components (ie, for the light-emitting layer B of the present invention, at least one host compound H B and typically at least one first TADF material E B , at least one second TADF material S B and optionally one or more other host compounds H B2 ) solution can further include volatile organic solvents. This volatile organic solvent can optionally be selected from tetrahydrofuran, dioxane, chlorobenzene, diethylene glycol diethyl ether, 2-(2-ethoxyethoxy) ethanol, γ-butyrolactone, N-methyl pyrrolidone, ethoxyethanol, xylene, toluene, anisole, phenol, acetonitrile, tetrahydrothiophene, benzonitrile, pyridine, trihydrofuran, triarylamine, cyclohexanone, acetone, propylene carbonate, ethyl acetate, benzene and PGMEA (propylene glycol monoethyl ether acetate). A combination of two or more solvents can also be used. After being applied in a liquid state, the layer can be subsequently dried and / or hardened by any means in this area, for example, under ambient conditions, at an elevated temperature (for example, about 50° C. or about 60° C.) or under reduced pressure.

[0512] Optionally, the organic electroluminescent device (e.g. OLED) can be illustratively a substantially white organic electroluminescent device or a blue organic electroluminescent device. Exemplarily, such a white organic electroluminescent device can comprise at least one (deep) blue emitter compound (e.g. TADF material EB ) and one or more luminophore compounds emitting green and / or red light. As mentioned above, energy transfer may optionally also exist between two or more compounds.

[0513] The entire organic electroluminescent device may form a thin layer having a thickness of no greater than 5 mm, no greater than 2 mm, no greater than 1 mm, no greater than 0.5 mm, no greater than 0.25 mm, no greater than 100 μm, or no greater than 10 μm.

[0514] Organic electroluminescent devices (e.g., OLEDs) can be small in size (e.g., a surface no larger than 5 mm 2 , not even larger than 1mm 2 ), medium (e.g., surface area of ​​0.5 to 20 cm 2 ), or large size (e.g., surface greater than 20cm 2 ). The organic electroluminescent devices (e.g., OLEDs) according to the present invention can optionally be used to generate screens, as large-area lighting devices, as luminous wallpaper, luminous window frames or glass, luminous labels, luminous bodies, or flexible screens or displays. In addition to common uses, organic electroluminescent devices (e.g., OLEDs) can also be used, for example, as luminous films, "smart packaging" labels, or innovative design elements. In addition, they can be used for cell detection and examination (e.g., as biomarkers).

[0515] One of the main uses of organic electroluminescent devices is to generate light. Therefore, the present invention also relates to a method for generating light in a desired wavelength range, comprising the steps of providing an organic electroluminescent device according to the present invention.

[0516] Therefore, another aspect of the present invention relates to a method for generating light in a desired wavelength range, comprising the steps of:

[0517] (i) providing an organic electroluminescent device according to the present invention; and

[0518] (ii) applying a current to the organic electroluminescent device.

[0519] Another aspect of the present invention relates to a method for manufacturing an organic electroluminescent device by assembling the above-mentioned components. The present invention also relates to a method for generating blue, green, yellow, orange, red, or white light, particularly blue or white light, by using the organic electroluminescent device. The present invention will be illustrated by way of examples and claims. Example

[0520] Cyclic voltammetry

[0521] Measure the concentration of organic molecules in dichloromethane or a suitable solvent and a suitable supporting electrolyte (such as 0.1 mol / l tetrabutylammonium hexafluorophosphate) at 10 -3 Cyclic voltammograms of a 1.5 mol / l solution. Measurements were performed at room temperature under nitrogen using a three-electrode assembly (working and counter electrodes: Pt wire, reference electrode: Pt wire), and calibrated using FeCp2 / FeCp2+ as an internal standard. HOMO data were corrected using ferrocene as an internal standard for SCE.

[0522] Density functional theory calculation

[0523] The molecular structure was optimized using the BP86 functional and the resolution of identity approach (RI). The excitation energies of the BP86-optimized structure were calculated using time-dependent DFT (TD-DFT). Orbital and excited-state energies were calculated using the B3LYP functional. The Def2-SVP basis set (and m4 grid for numerical integration) were employed. All calculations were performed using the Turbomole package.

[0524] Photophysical measurements

[0525] Sample preparation of host materials and organic TADF emitters:

[0526] Stock solution 1: Dissolve 10 mg of sample (organic TADF material or host material) in 1 ml of solvent.

[0527] Stock solution 2: Dissolve 10 mg of PMMA in 1 ml of solvent.

[0528] The solvent is typically selected from toluene, chlorobenzene, dichloromethane and chloroform.

[0529] 1 ml of stock solution 1 was added to 9 ml of stock solution 2 using an Eppendorf pipette to achieve a sample content of 10 wt % in PMMA.

[0530] Alternatively, the photophysical properties of the host material can be characterized in neat thin films of the host material.

[0531] Sample preparation of fluorescence emitters and NRCT emitters:

[0532] Stock solution 1: Dissolve 10 mg of sample (fluorescence emitter and NRCT emitter) in 1 ml of solvent.

[0533] Stock solution 1a: Add 9 mL of solvent to 1 mL of stock solution 1.

[0534] Stock solution 2: Dissolve 10 mg of PMMA in 1 ml of solvent.

[0535] The solvent is typically selected from toluene, chlorobenzene, dichloromethane and chloroform.

[0536] 1 ml of stock solution 1a was added to 9 ml of stock solution 2 using an Eppendorf pipette to achieve a sample content of 1 wt % in PMMA.

[0537] Alternatively, the photophysical properties of the fluorescent emitter can be characterized in solution, using a solution containing the fluorescent emitter at a concentration of 0.001 mg / ml.

[0538] Sample pretreatment: spin coating

[0539] Instrument: Spin150, SPS euro.

[0540] Program: 1) 3 seconds, 400 U / min; 2) 20 seconds, 1000 U / min, 1000 U / s. 3) 10 seconds, 4000 U / min, 1000 U / s. After coating, the film was dried at 70°C for 1 minute.

[0541] Photoluminescence spectroscopy and TCSPC (Time-correlated single-photon counting)

[0542] Steady-state emission spectra were recorded using a Horiba Scientific Modell FluoroMax-4 instrument equipped with a 150W xenon arc lamp, Hamamatsu R928 photomultiplier tubes for excitation and emission monochromators, and a time-correlated single photon counting option. Emission and excitation spectra were corrected using standard calibration fits.

[0543] The excited-state lifetimes were determined according to the TCSPC method using an FM-2013 apparatus and a Horiba Yvon TCSPC hub.

[0544] Excitation source:

[0545] NanoLED 370 (wavelength: 371nm, pulse duration: 1.1ns)

[0546] NanoLED 290 (wavelength: 294nm, pulse duration: <1ns)

[0547] SpectraLED 310 (wavelength: 314nm)

[0548] SpectraLED 355 (wavelength: 355nm).

[0549] Data analysis (exponential fitting) was performed using the DataStation software suite and DAS6 analysis software. Chi-squared-test was used for fitting.

[0550] Photoluminescence quantum yield measurement

[0551] The photoluminescence quantum yield (PLQY) was measured using an absolute PL quantum yield measurement C9920-03G system (Hamamatsu Photonics). Quantum yield and CIE coordinates were determined using software U6039-05 version 3.6.0.

[0552] The emission maximum is in nm, the quantum yield Φ is in %, and the CIE coordinates are x,y values.

[0553] PLQY was determined using the following protocol:

[0554] 1) Quality assurance: Anthracene in ethanol (known concentration) as a reference

[0555] 2) Excitation wavelength: Determine the maximum absorption value of organic molecules and use this wavelength to excite the molecules

[0556] 3) Measurement

[0557] Measure the quantum yield of solution or thin film samples under a nitrogen atmosphere. Calculate the yield using the following equation:

[0558]

[0559] where n photon represents photon counts, and Int. represents intensity.

[0560] Production and characterization of organic electroluminescent devices

[0561] OLED devices comprising the organic molecules of the invention can be produced by vacuum deposition. If a layer comprises more than one compound, the weight percentage of the compound or compounds is expressed in %. The total weight percentage value is 100%, so if no % value is given for a compound, the fraction of this compound is equal to the difference between the given value and 100%. Characterization of non-fully optimized OLEDs: Using standard methods, the electroluminescence spectrum is measured, the intensity-dependent external quantum efficiency (in %) is calculated from the light detected by the photodiode and the current. The lifetime of the OLED device is determined from the time at a constant current density (in mA / cm 2) during operation under normal operating conditions. The LT50 value corresponds to the time it takes for the measured brightness to drop to 50% of the initial brightness. Similarly, LT80 corresponds to the time it takes for the measured brightness to drop to 80% of the initial brightness. LT97 corresponds to the time it takes for the measured brightness to drop to 97% of the initial brightness, and so on.

[0562] Perform accelerated lifetime measurements (e.g., apply increasing current densities). For example, 500 cd / m 2 The LT80 value is determined using the following equation:

[0563]

[0564] where L0 represents the initial luminance under the applied current density.

[0565] The average of this value for several pixels (usually 2 to 8) is used as the standard deviation between these pixels. The data shows a data series for one OLED pixel.

[0566] Examples D1 and D2 and Comparative Example C1

[0567]

[0568]

[0569] Table 1 Physicochemical properties of ingredients

[0570] <![CDATA[E HOMO [eV]]> <![CDATA[E LUMO [eV]]> S1[eV] T1[eV] <![CDATA[mCBP(H B )]]> -6.02 -2.42 3.60 2.82 <![CDATA[TADF1(E B )]]> -5.48 -2.73 2.75 2.59 <![CDATA[TADF2(E B )]]> -5.45 -2.63 2.82 <![CDATA[TADF3(E B )]]> -5.55 -2.69 2.86 <![CDATA[TADF4(E B )]]> -5.72 -2.95 2.77 2.60 <![CDATA[TADF5(E B )]]> -5.66 -2.69 2.97 <![CDATA[TADF6(E B )]]> -5.85 -3.20 2.65 2.51 <![CDATA[Emitter 1(S B )]]> -5.99 -3.35 2.64 <![CDATA[Emitter 2 (S B )]]> -5.79 -3.12 2.67

[0571] Table 2. Device Settings

[0572]

[0573]

[0574] Device D1 at 1000cd / m 2 The external quantum efficiency (EQE) was 16.7% at 15 mA / cm 2 The LT80 value under the condition of 558 hours and 10mA / cm 2 The emission maximum is at 519 nm, with a corresponding CIEx value of 0.314 and a CIEy value of 0.589.

[0575] Device D2 is 1000cd / m 2 The external quantum efficiency (EQE) was 15.1% at 15 mA / cm 2 The LT80 value under the condition of 10mA / cm 2The emission maximum is at 518 nm, with a corresponding CIEx value of 0.301 and a CIEy value of 0.596.

[0576] Comparative device C1 comprises the same layer arrangement as device D1, except that the light-emitting layer contains only emitter 1 and mCBP. 2 The EQE at 15 mA / cm2 is 14.5%. 2 The LT80 value under 10mA / cm 2 The emission maximum is at 516 nm, with a corresponding CIEx value of 0.293 and a CIEy value of 0.596.

[0577] In a direct comparison between device D1 and comparative device C1, it can be observed that at 15 mA / cm 2 The LT80 value increased by 5.03 times at 1000cd / m 2 The external quantum efficiency increased to 1.15 times.

[0578] In a direct comparison of device D2 and comparative device C1, it can be observed that at 15 mA / cm 2 The LT80 value increased by 2.38 times, and at 1000cd / m 2 The external quantum efficiency increased to 1.04 times.

[0579] Other material characterization

[0580] TADF1

[0581] TADF1 (1 wt % in PMMA) has a maximum emission wavelength of 469 nm, a full width at half maximum (FWHM) of 0.16 eV, a CIEy coordinate of 0.16, and a PLQY of 80%.

[0582] TADF2

[0583] TADF2 (1 wt% in PMMA) has a maximum emission wavelength of 447 nm, a full width at half maximum (FWHM) of 0.14 eV, a CIEy coordinate of 0.04, and a PLQY of 93%.

[0584] TADF3

[0585] TADF3 (10 wt % in PMMA) has a maximum emission wavelength of 482 nm, a full width at half maximum (FWHM) of 0.40 eV, a CIEy coordinate of 0.32, and a PLQY of 70%.

[0586] TADF4

[0587] TADF4 (1 wt % in PMMA) has a maximum emission wavelength of 470 nm, a full width at half maximum (FWHM) of 0.20 eV, a CIEy coordinate of 0.18, and a PLQY of 83%.

[0588] TADF5

[0589] TADF5 (10 wt % in PMMA) has a maximum emission wavelength of 464 nm, a full width at half maximum (FWHM) of 0.41 eV, a CIEy coordinate of 0.18, and a PLQY of 71%.

[0590] TADF6

[0591] The maximum emission wavelength of TADF6 (1 wt% in PMMA) is 496 nm, the full width at half maximum (FWHM) is 0.24 eV, and the CIEy coordinate is 0.52.

[0592] Emitter 1

[0593] Emitter 1 (10 wt% in PMMA) has a maximum emission wavelength of 521 nm, a CIEy coordinate of 0.56, and a PLQY of 59%.

[0594] Emitter 2

[0595] Emitter 1 (1 wt% in PMMA) has a maximum emission wavelength of 490 nm, a CIEy coordinate of 0.46, and a PLQY of 88%.

[0596] Example D3 and Comparative Example C2

[0597] Table 3a. Device Settings

[0598]

[0599]

[0600] Test results

[0601] Table 4a. Test results of D3 and C2

[0602]

[0603] In a direct comparison between device D3 and comparative device C2, it can be observed that at 15 mA / cm 2 The LT80 value increased by 2.69 times at 1000cd / m 2 The external quantum efficiency increased by 1.09 times.

[0604] Examples D4 and D5 and Comparative Example C3

[0605] Table 3b. Device Settings

[0606]

[0607]

[0608] Among them, different TADF materials E in D4 and D5 B as follows:

[0609] - For D4-1 and D5-1, E B It is TADF1,

[0610] - For D4-4 and D5-4, E B It's TADF4,

[0611] - For D4-5 and D5-5, E B It's TADF5.

[0612] Test results

[0613] Table 4b. Test results of D4, D5 and C3

[0614]

[0615] In a direct comparison of devices D4 (i.e., D4-1, D4-4, and D4-5) and D5 (i.e., D5-1, D5-4, and D5-5) with comparative device C3, it can be observed that D4-1, D4-4, D4-5, D5-1, and D5-5 exhibited significant differences in the ion exchange rate at 15 mA / cm 2 In addition, compared with C3, the external quantum efficiency of D4-1, D4-4, D4-5 and D5-5 at 1000 cd / m 2 The time also increased significantly.

Claims

1. An organic electroluminescent device, comprising a light-emitting layer B, wherein the light-emitting layer B comprises: (i) Main material H B , which has the lowest excited singlet energy level S1 H , the lowest excited triplet state energy level T1 H and energy E HOMO (H B )'s highest occupied molecular orbital HOMO (H B ); (ii) First Thermally Activated Delayed Fluorescence (TADF) Material E B , which has the lowest excited singlet energy level S1 E , the lowest excited triplet state energy level T1 E and energy E HOMO (E B )'s highest occupied molecular orbital HOMO(E B );and (iii) Emitter material S B , which has the lowest excited singlet energy level S1 S and energy E HOMO (S B )'s highest occupied molecular orbital HOMO(S B ); The relationships expressed by the following equations (1) to (5) hold true: S1 H >S1 E (1) S1 H >S1 S (2) S1 E >S1 S (3) E HOMO (E B )>E HOMO (S B ) (4) E HOMO (E B )>E HOMO (H B ) (5), and Among them, TADF material E B Containing a structure of formula I-NRCT or consisting of a structure of formula I-NRCT composition: in o is 0 or 1; m=1-o; X 1 is N or B; X 2 is N or B; X 3 is N or B; W is selected from Si(R 3S )2、C(R 3S )2 and BR 3S ; R 1S 、R 2S and R 3S Each of which is independently selected from: C1-C5 alkyl, which is optionally substituted by one or more substituents R 6S replace; C6-C 60 Aryl, which is optionally substituted by one or more substituents R 6S Replacement; and C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 6S replace; R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI Each independently selected from: Hydrogen, deuterium, N(R 5S )2, OR 5S ,Si(R 5S )3,B(OR 5S )2, OSO2R 5S , CF3, CN, halogen, C1-C 40 Alkyl, which is optionally substituted by one or more substituents R 5S and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5S C=CR 5S 、C≡C、Si(R 5S )2、Ge(R 5S )2、Sn(R 5S )2. C=O, C=S, C=Se, C=NR 5S 、P(=O)(R 5S )、SO、SO2、NR 5S , O, S, or CONR 5S replace; C1-C 40 Alkoxy, which is optionally substituted by one or more substituents R 5S and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5S C=CR 5S 、C≡C、Si(R 5S )2、Ge(R 5S )2、Sn(R 5S )2. C=O, C=S, C=Se, C=NR 5S 、P(=O)(R 5S )、SO、SO2、NR 5S , O, S, or CONR 5S replace; C1-C 40 Thioalkoxy, which is optionally substituted by one or more substituents R 5S and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5S C=CR 5S 、C≡C、Si(R 5S )2、Ge(R 5S )2. Sn(R 5S )2、C=O、C=S、C=Se、C=NR 5S 、P(=O)(R 5S )、SO、SO2、NR 5S 、O、S or CONR 5S replace; C2-C 40 Alkenyl, which is optionally substituted by one or more substituents R 5S and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5S C=CR 5S 、C≡C、Si(R 5S )2、Ge(R 5S )2、Sn(R 5S )2. C=O, C=S, C=Se, C=NR 5S 、P(=O)(R 5S )、SO、SO2、NR 5S , O, S, or CONR 5S replace; C2-C 40 Alkynyl, which is optionally substituted by one or more substituents R 5S and wherein one or more non-adjacent CH2- groups are each optionally replaced by R 5S C=CR 5S 、C≡C、Si(R 5S )2、Ge(R 5S )2、Sn(R 5S )2. C=O, C=S, C=Se, C=NR 5S 、P(=O)(R 5S )、SO、SO2、NR 5S , O, S, or CONR 5S replace; C6-C 60 Aryl, which is optionally substituted by one or more substituents R 5S Replacement; and C3-C 57 Heteroaryl, which is optionally substituted by one or more substituents R 5S replace; R 5S is independently selected at each occurrence from the group consisting of: hydrogen, deuterium, OPh, CF3, CN, F, C1-C5 alkyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C1-C5 alkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C1-C5 thioalkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C2-C5 alkenyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C2-C5 alkynyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C6-C 18 aryl, optionally substituted with one or more C1-C5 alkyl substituents; C3-C 17 heteroaryl, optionally substituted with one or more C1-C5 alkyl substituents; N(C6-C 18 Aryl)2; N(C3-C 17 heteroaryl)2; and N(C3-C 17 Heteroaryl)(C6-C 18 aryl); R 6S is independently selected at each occurrence from hydrogen, deuterium, OPh, CF3, CN, F, C1-C5 alkyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C1-C5 alkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C1-C5 thioalkoxy, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C2-C5 alkenyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C2-C5 alkynyl, wherein optionally one or more hydrogen atoms are independently replaced by deuterium, CN, CF3 or F; C6-C 18 aryl, optionally substituted with one or more C1-C5 alkyl substituents; C3-C 17 heteroaryl, optionally substituted with one or more C1-C5 alkyl substituents; N(C6-C 18 aryl)2, N(C3-C 17 heteroaryl)2; and N(C3-C 17 Heteroaryl)(C6-C 18 aryl); Two or more adjacent ones are selected from R I 、R II 、R III 、R IV 、R V 、R VI 、R VII 、R VIII 、R IX 、R X and R XI The substituents may optionally form a monocyclic or polycyclic, aliphatic, aromatic and / or benzo-fused ring system with each other; and where X 1 、X 2 and X 3 At least one of them is B, and X 1 、X 2 and X 3 At least one of them is N.

2. The organic electroluminescent device according to claim 1, wherein the relationship represented by at least one of the following formulas (6) and (7) holds true: 0.2eV≤E HOMO (E B )-E HOMO (S B )≤0.8eV (6) 0.2eV≤E HOMO (E B )-E HOMO (H B )≤0.8eV (7).

3. The organic electroluminescent device according to claim 1 or 2, characterized in that The TADF material E B ΔE ST value is less than 0.4eV, the ΔE ST Value corresponds to S1 E and T1 E energy difference.

4. The organic electroluminescent device according to claim 1 or 2, wherein the relationship represented by formula (8) holds: S1 S >T1 E (8)。 5. The organic electroluminescent device according to claim 1 or 2, wherein: The emitter material S B With TADF materials E B The mass ratio (S B :E B )>1. The organic electroluminescent device according to claim 1 , wherein the organic electroluminescent device is a device selected from the group consisting of an organic light emitting diode, a light emitting electrochemical cell, and a light emitting transistor.

7. The organic electroluminescent device according to claim 1 or 2, wherein: The emitter material S B Selected from fluorescent emitters and organic TADF emitters, the organic TADF emitter being characterized in that it has a ΔE of less than 0.4 eV ST Value, ΔE ST Value corresponds to S1 S and T1 S The energy difference between them.

8. The organic electroluminescent device according to claim 1 or 2, wherein the relationship represented by (10a), (10b) or (10c) holds: E HOMO (H B )>E HOMO (S B )(10a) AND HOMO (S B )>And HOMO (H B )(10b) -0.1eV≤E HOMO (H B )-E HOMO (S B )≤0.1eV(10c)。 9. The organic electroluminescent device according to claim 1 or 2, wherein the lowest unoccupied molecular orbital LUMO (E B ) LUMO (E B ) and the lowest unoccupied molecular orbital LUMO (S B ) LUMO (S B ) satisfies the formula (11): E LUMO (E B )>E LUMO (S B ) (11).

10. The organic electroluminescent device according to claim 1 or 2, wherein: The light-emitting layer B includes: (i) 39.8-98 wt% of host compound H B ; (ii) 0.1-50% by weight of TADF material E B ; (iii) 0.1-50 wt. % of emitter material S B ; (iv) 0-60 wt% of one or more compounds other than H B Other main compounds H B2 ;and (v) 0-60% by weight of one or more solvents.

11. The organic electroluminescent device according to claim 1 or 2, wherein: The light-emitting layer B includes 0.1-10 wt% of TADF material E B .

12. The organic electroluminescent device according to claim 1 or 2, wherein: The device exhibits a maximum emission wavelength value λ of 440 to 560 nm. max (D).

13. A method for generating visible light, comprising the following steps: (i) providing an organic electroluminescent device according to any one of claims 1 to 12; and (ii) applying a current to the organic electroluminescent device.

14. A thermally activated delayed fluorescence (TADF) material E B The use of the thermally activated delayed fluorescence (TADF) material and at least one host material H B and at least one emitter material S B The combination is used in the light-emitting layer to increase the life of the organic electroluminescent device.

15. The use according to claim 14, characterized in that The light-emitting layer is characterized by being as described in claim 1 or 2.

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