The present invention relates to organic electroluminescent devices comprising a light-emitting layer B comprising a host material H^B, a first thermally activated delayed fluorescence (TADF) material E^B, and a depopulation agent S^B.

DESCRIPTION

Organic electroluminescent devices containing one or more light-emitting layers based on organics such as, e.g., organic light emitting diodes (OLEDs), light emitting electrochemical cells (LECs) and light-emitting transistors gain increasing importance. In particular, OLEDs are promising devices for electronic products such as e.g. screens, displays and illumination devices. In contrast to most electroluminescent devices essentially based on inorganics, organic electroluminescent devices based on organics are often rather flexible and producible in particularly thin layers. The OLED-based screens and displays already available today bear particularly beneficial brilliant colors, contrasts and are comparably efficient with respect to their energy consumption.

A central 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 an organic electroluminescent device, holes and electrons are injected from an anode and a cathode, respectively, to the light-emitting layer. Typically, a hole transport layer is located between light-emitting layer and the anode, and an electron transport layer is located between light-emitting layer and the cathode. The different layers are sequentially disposed. Excitons of high energy are then generated by recombination of the holes and the electrons. The decay of such excited states (e.g., singlet states such as S1 and/or triplet states such as T1) to the ground state (S0) desirably leads to light emission.

In order to enable efficient energy transport and emission, an organic electroluminescent device comprises one or more host compounds and one or more emitter compounds as dopants.

Challenges when generating organic electroluminescent devices are thus the improvement of the illumination level of the devices (i.e., brightness per current), obtaining a desired light spectrum and achieving suitable (long) lifespans.

It has been tried to admix electron trap materials to the light-emitting layers to enhance lifespan (EP-A 2610937). Herein, the electron trap materials have a lowest unoccupied molecular orbital LUMO and a highest occupied molecular orbital HOMO, which are both lower than the LUMOs and HOMOs of the dopant (a conventional fluorescent emitter) and the host. This mixture however is comparably inefficient. Thus, the dopant is usable at very low concentrations only, while the electron trap materials are used in excess to the dopant.

There is still a lack of efficient and stable OLEDs that emit in the deep blue region of the visible light spectrum, which would be expressed by a small CIE_yvalue. Accordingly, there is still the unmet technical need for organic electroluminescent devices which have a long lifetime and high quantum yields, in particular in the deep blue range.

Surprisingly, it has been found that an organic electroluminescent device's light-emitting layer comprising one thermally activated delayed fluorescence (TADF) emitter, a depopulation agent and a host material provides an organic electroluminescent device having good lifetime and quantum yields, particular despite exhibiting deep blue emission.

Accordingly, one aspect of the present invention relates to an organic electroluminescent device which comprises a light-emitting layer B comprising:

- (i) a host material H^B, which has a lowest unoccupied molecular orbital LUMO(H^B) having an energy E^LUMO(H^B) and a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B),
- (ii) a first thermally activated delayed fluorescence (TADF) material E^B, which has a lowermost excited singlet state energy level S1^E, a lowermost excited triplet state energy level T1^E, a lowest unoccupied molecular orbital LUMO(E^B) having an energy E^LUMO(E^B) and a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B); and
- (iii) an depopulation agent S^B, which has a lowermost excited singlet state energy level S1^S, a lowermost excited triplet state energy level T1^S, a lowest unoccupied molecular orbital LUMO(S^B) having an energy E^LUMO(S^B) and a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B),
- wherein E^Bemits thermally activated delayed fluorescence; and wherein the relations expressed by the following formulas (1) to (2) and either (3a) and (3b) or (4a) and (4b) apply:

S1^S≥S1^E (1)

T1^S≥2.5 eV (2)

E^LUMO(E^B)<E^LUMO(H^B) (3a)

0.2 eV<E^LUMO(E^B)−E^LUMO(S^B)<0.5 eV (3b)

E^LUMO(E^B)>E^LUMO(H^B) (4a)

0.2 eV<E^LUMO(H^B)−E^LUMO(S^B)<0.5 eV (4b).

According to the invention, the lowermost excited singlet state energy level S1^Sof the depopulation agent S^Bis higher or equal in energy than the lowermost excited singlet state energy level S1^Eof the thermally activated delayed fluorescence (TADF) material E^B. The lowermost excited triplet state energy level T1^Sof the depopulation agent S^Bis larger than or equal to 2.5 eV. In one aspect of the invention, the lowest unoccupied molecular orbital of the host material H^Bis higher in energy than the lowest unoccupied molecular orbital of the TADF material E^B(i.e. the TADF material E^Bacts as the main electron transporting material).

In this aspect, the lowest unoccupied molecular orbital of the depopulation agent S^Bis lower in energy than the lowest unoccupied molecular orbital of the TADF material E^Bby at least 0.2 eV and by 0.5 eV at the maximum, in particular by at least 0.25 eV and by 0.4 eV at the maximum.

In an alternative aspect of the invention, the lowest unoccupied molecular orbital of the host material H^Bis lower in energy than the lowest unoccupied molecular orbital of the TADF material E^B(i.e. the host material H^Bacts as the main electron transporting material). In this aspect, the lowest unoccupied molecular orbital of the depopulation agent S^Bis lower in energy than the lowest unoccupied molecular orbital of the host material H^Bby at least 0.2 eV and by 0.5 eV at the maximum, in particular by at least 0.25 eV and by 0.4 eV at the maximum.

In both aspects of the invention, the lowest unoccupied molecular orbital of the depopulation agent S^Bis lower in energy than the lowest unoccupied molecular orbital of the main electron transporting material by at least 0.2 eV and by 0.5 eV at the maximum, in particular by at least 0.25 eV and by 0.4 eV at the maximum.

In one embodiment of the invention, the lowermost excited triplet state energy level T1^Sof the depopulation agent S^Bis between 2.5 eV and 3.5 eV, preferably between 2.6 eV and 3.2 eV, more preferably between 2.7 eV and 3.1 eV or even between 2.8 eV and 3.0 eV.

In a preferred embodiment, the relation expressed by the formulas (3a) and (3b) apply. In an alternative preferred embodiment, the relation expressed by the formulas (4a) and (4b) apply.

In one embodiment of the invention, the mass ratio of TADF material to depopulation agent (E^B:S^B) is >1. In one embodiment of the invention, the mass ratio E^B:S^Bis in the range of 1.5:1 to 20:1, in the range of 2:1 to 10:1, or in the range of 3:1 to 5:1. For example, the mass ratio E^B:S^Bis in the range of (approximately) 3:1, 4:1, 5:1 or 6:1.

In one embodiment, the relation expressed by the following formula (5a) applies:

E^HOMO(E^B)>E^HOMO(H^B) (5a).

In another embodiment, the relation expressed by the following formula (5b) applies:

E^HOMO(E^B)<E^HOMO(H^B) (5b).

In an embodiment of the present invention, the relations expressed by the following formulae (3a) and (5a) both apply:

E^LUMO(E^B)<E^LUMO(H^B) (3a);

and

E^HOMO(E^B)>E^HOMO(H^B) (5a).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^LUMO(E^B)<E^LUMO(H^B)>E^LUMO(S^B);

and

E^HOMO(E^B)>E^HOMO(H^B)>E^HOMO(S^B).

In an alternative embodiment of the present invention, the relations expressed by the following formulae (4a) and (5b) both apply:

E^LUMO(E^B)>E^LUMO(H^B) (4a);

and

E^HOMO(E^B)<E^HOMO(H^B) (5b).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^LUMO(E^B)>E^LUMO(H^B)>E^LUMO(S^B);

and

E^HOMO(E^B)<E^HOMO(H^B)>E^HOMO(S^B).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^LUMO(E^B)>E^LUMO(S^B);

and

E^LUMO(H^B)>E^LUMO(S^B).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^HOMO(E^B)>E^HOMO(S^B);

and

E^HOMO(H^B)>E^HOMO(S^B).

In an embodiment of the present invention, all of the relations expressed by the following formulae apply:

E^LUMO(E^B)<E^LUMO(H^B);

E^HOMO(E^B)>E^HOMO(H^B);

E^LUMO(E^B)>E^LUMO(S^B);

E^LUMO(H^B)>E^LUMO(S^B);

E^HOMO(E^B)>E^HOMO(S^B);

and

E^HOMO(H^B)>E^HOMO(S^B).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^LUMO(H^B)>E^LUMO(E^B)>E^LUMO(S^B);

and

E^HOMO(E^B)>E^HOMO(H^B)>E^HOMO(S^B).

In an embodiment of the present invention, the relation expressed by the following formula applies:

E^LUMO(H^B)>E^LUMO(E^B)>E^LUMO(S^B)>E^HOMO(E^B)>E^HOMO(H^B)>E^HOMO(S^B).

In an alternative embodiment of the present invention, all of the relations expressed by the following formulae apply:

E^LUMO(E^B)>E^LUMO(H^B);

E^HOMO(E^B)<E^HOMO(H^B);

E^LUMO(E^B)>E^LUMO(S^B);

E^LUMO(H^B)>E^LUMO(S^B);

E^HOMO(E^B)>E^HOMO(S^B);

and

E^HOMO(H^B)>E^HOMO(S^B).

In an embodiment of the present invention, the relations expressed by the following formulae apply:

E^LUMO(E^B)>E^LUMO(H^B)>E^LUMO(S^B);

and

E^HOMO(H^B)>E^HOMO(E^B)>E^HOMO(S^B).

In an embodiment of the present invention, the relation expressed by the following formula applies:

E^LUMO(E^B)>E^LUMO(H^B)>E^LUMO(S^B)>E^HOMO(H^B)>E^HOMO(E^B)>E^HOMO(S^B).

I.e. the highest occupied molecular orbital of the TADF material E^Bis lower in energy than the highest occupied molecular orbital of the host material H^B.

In one embodiment, the relation expressed by the following formula (6) applies:

E^HOMO(S^B)<E^HOMO(H^B) (6)

I.e. the highest occupied molecular orbital of the depopulation agent S^Bis lower in energy than the highest occupied molecular orbital of the host material H^B.

In an alternative embodiment, E^HOMO(S^B)>E^HOMO(H^B).

As used herein, the terms “TADF material” and “TADF emitter” may be understood interchangeably. When one of the terms “emitter” “emitter compound” or the like is used, this may be understood in that preferably a TADF material of the present invention is meant, in particular one or those designated as E^Band S^B, respectively.

According to the present invention, a TADF material is characterized in that it exhibits a ΔE_STvalue, which corresponds to the energy difference between the lowermost excited singlet state (S1) and the lowermost excited triplet state (T1), of less than 0.4 eV, preferably less than 0.3 eV, more preferably less than 0.2 eV, even more preferably less than 0.1 eV or even less than 0.05 eV.

Accordingly in an embodiment of the present invention, the TADF material E^Bis characterized in that it has a ΔE_STvalue, which corresponds to the energy difference between S1^Eand T1^E, of less than 0.4 eV. In a preferred embodiment of the present invention, the TADF material E^Bis characterized in that it has a ΔE_STvalue of less than 0.3 eV, less than 0.2 eV, less than 0.1 eV, or even less than 0.05 eV.

In one embodiment of the present invention, the depopulation agent S^Bis a TADF material, i.e., one or more TADF emitter. Accordingly in an embodiment of the present invention, the depopulation agent S^Bis characterized in that it has a ΔE_STvalue, which corresponds to the energy difference between S1^Sand T1^S, of less than 0.4 eV. In a preferred embodiment of the present invention, the depopulation agent S^Bis characterized in that it has a ΔE_STvalue of less than 0.3 eV, less than 0.2 eV, less than 0.1 eV, or even less than 0.05 eV.

In one embodiment of the present invention, the TADF material E^Band the depopulation agent S^Bare both organic TADF emitters.

It will be understood that the light-emitting layer B may also comprise more than one TADF materials E^Band/or more than one depopulation agents S^Beach having the properties as described herein. According to the present invention, the light-emitting layer B comprises at least one TADF material E^Band at least one depopulation agent S^Beach having the properties as described herein. According to one embodiment of the present invention, the light-emitting layer B comprises one TADF material E^Band one depopulation agent S^Beach having the properties as described herein.

As used herein, the terms organic electroluminescent device and opto-electronic light-emitting devices may be understood in the broadest sense as any device comprising a light-emitting layer B comprising a host material H^B, a TADF material E^Band a depopulation agent S^B.

The organic electroluminescent device may be understood in the broadest sense as any device based on organic materials that is suitable for emitting light in the visible or nearest ultraviolet (UV) range, i.e., in the range of a wavelength of from 380 to 800 nm. More preferably, organic electroluminescent device may be able to emit light in the visible range, i.e., of from 400 to 800 nm.

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

Particularly preferably, the organic electroluminescent device is an organic light emitting diode (OLED). Optionally, the organic electroluminescent device as a whole may be intransparent, semi-transparent or (essentially) transparent.

The term “layer” as used in the context of the present invention preferably is a body that bears an extensively planar geometry.

The light-emitting layer B preferably bears a thickness of not more than 1 mm, more preferably not more than 0.1 mm, even more preferably not more than 10 μm, even more preferably not more than 1 μm, in particular not more than 0.1 μm.

In a preferred embodiment, the thermally activated delayed fluorescence (TADF) material E^Bis an organic TADF emitter. According to the invention, organic emitter or organic material means that the emitter or material (predominantly) consists of the elements hydrogen, carbon, nitrogen, and optionally fluorine and optionally oxygen. Particularly preferably, it does not contain any transition metals.

In a preferred embodiment, the TADF material E^Bis an organic TADF emitter. In a preferred embodiment, the depopulation agent S^Bis an organic TADF emitter. In a more preferred embodiment, the TADF material E^Band the depopulation agent S^Bare both organic TADF emitters.

In a particularly preferred embodiment, the at least one TADF material E^Bis a blue TADF emitter, preferably a deep-blue TADF emitter.

The person skilled in the art will notice that the light-emitting layer B will typically be incorporated in the organic electroluminescent device of the present invention. Preferably, such 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.

Preferably, the anode layer A contains at least one component selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicium, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and mixtures of two or more thereof.

Preferably, the cathode layer C contains at least one component 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.

Preferably, the light-emitting layer B is located between an anode layer A and a cathode layer C. Accordingly, the general set-up is preferably A-B-C. This does of course not exclude the presence of one or more optional further layers. These can be present at each side of A, of B and/or of C.

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

A) an anode layer A containing at least one component selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicium, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and mixtures of two or more thereof;

B) the light-emitting layer B; and

C) a cathode layer C containing at least one component 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,

wherein the light-emitting layer B is located between the anode layer A and the a cathode layer C.

In one embodiment, when the organic electroluminescent device is an OLED, it may optionally comprise the following layer structure:

A) an anode layer A, exemplarily comprising indium tin oxide (ITO);

HTL) a hole transport layer HTL;

B) a light-emitting layer B according to present invention as described herein;

ETL) an electron transport layer ETL; and

C) a cathode layer, exemplarily comprising Al, Ca and/or Mg.

Preferably, the order of the layers herein is A-HTL-B-ETL-C.

Furthermore, the organic electroluminescent device may optionally comprise one or more protective layers protecting the device from damaging exposure to harmful species in the environment including, exemplarily moisture, vapor and/or gases.

Preferably, the anode layer A is located on the surface of a substrate. The substrate may be formed by any material or composition of materials. Most frequently, glass slides are used as substrates. Alternatively, thin metal layers (e.g., copper, gold, silver or aluminum films) or plastic films or slides may be used. This may allow a higher degree of flexibility. The anode layer A is mostly composed of materials allowing to obtain an (essentially) transparent film. As at least one of both electrodes should be (essentially) transparent in order to allow light emission from the OLED, either the anode layer A or the cathode layer C transparent. Preferably, the anode layer A comprises a large content or even consists of transparent conductive oxides (TCOs).

Such anode layer A may exemplarily comprise indium tin oxide, aluminum zinc oxide, fluor tin oxide, indium zinc oxide, PbO, SnO, zirconium oxide, molybdenum oxide, vanadium oxide, wolfram oxide, graphite, doped Si, doped Ge, doped GaAs, doped polyaniline, doped polypyrrol and/or doped polythiophene.

Particularly preferably, the anode layer A (essentially) consists 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 oxides (TCOs) may be compensated by using a hole injection layer (HIL). Further, the HIL may facilitate the injection of quasi charge carriers (i.e., holes) in that the transport of the quasi charge carriers from the TCO to the hole transport layer (HTL) is facilitated. The hole injection layer (HIL) may comprise poly-3,4-ethylendioxy thiophene (PEDOT), polystyrene sulfonate (PSS), MoO₂, V₂O₅, CuPC or CuI, in particular a mixture of PEDOT and PSS. The hole injection layer (HIL) may also prevent the diffusion of metals from the anode layer A into the hole transport layer (HTL). The HIL may exemplarily comprise PEDOT:PSS (poly-3,4-ethylendioxy thiophene: polystyrene sulfonate), PEDOT (poly-3,4-ethylendioxy thiophene), 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-tolylbenzene-1,4-diamine), NPB (N,N′-nis-(1-naphthalenyl)-N,N′-bis-phenyl-(1,1′-biphenyl)-4,4′-diamine), NPNPB (N, N′-diphenyl-N,N′-di-[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-hexaazatriphenylen-hexacarbonitrile) and/or Spiro-NPD (N,N′-diphenyl-N,N′-bis-(1-naphthyl)-9,9′-spirobifluorene-2,7-diamine).

Adjacent to the anode layer A or hole injection layer (HIL) typically a hole transport layer (HTL) is located. Herein, any hole transport compound may be used.

Exemplarily, electron-rich heteroaromatic compounds such as triarylamines and/or carbazoles may be used as hole transport compound. The HTL may decrease the energy barrier between the anode layer A and the light-emitting layer B (serving as emitting layer (EML)). The hole transport layer (HTL) may also be an electron blocking layer (EBL). Preferably, hole transport compounds bear comparably high energy levels of their triplet states T1.

Exemplarily the hole transport layer (HTL) may comprise a star-shaped heterocycle such as tris(4-carbazoyl-9-ylphenyl)amine (TCTA), poly-TPD (poly(4-butylphenyl-diphenyl-amine)), [alpha]-NPD (poly(4-butylphenyl-diphenyl-amine)), TAPC (4,4′-cyclohexyliden-bis[N,N-bis(4-methylphenyl)benzenamine]), 2-TNATA (4,4′,4″-tris[2-naphthyl(phenyl)-amino]triphenylamine), Spiro-TAD, DNTPD, NPB, NPNPB, MeO-TPD, HAT-CN and/or TrisPcz (9,9′-diphenyl-6-(9-phenyl-9H-carbazol-3-yl)-9H,9′H-3,3′-bicarbazole). In addition, the HTL may comprise 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 exemplarily be used as inorganic dopant.

Tetrafluorotetracyanoquinodimethane (F4-TCNQ), copper-pentafluorobenzoate (Cu(I)pFBz) or transition metal complexes may exemplarily be used as organic dopant.

The EBL may exemplarily comprise mCP (1,3-bis(carbazol-9-yl)benzene), TCTA, 2-TNATA, mCBP (3,3-di(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, 9-[3,5-bis(2-dibenzofuranyl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzothiophenyl)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).

According to the invention, the emission layer B comprises at least one host material H^B, the TADF material E^Band the electron-trap material S^B.

In a preferred embodiment of the invention, the light-emitting layer B comprises 40-98%, more preferably 57-93%, even more preferably 74-87% by weight of the host compound H^B.

In a preferred embodiment of the invention, the light-emitting layer B comprises 1-50%, more preferably 5-35%, even more preferably 10-20% by weight of the TADF material E^B.

In a preferred embodiment of the invention, the light-emitting layer B comprises 1-10%, more preferably 2-8%, even more preferably 3-6% by weight of the depopulation agent S^B.

In a preferred embodiment of the invention, the light-emitting layer B comprises up to 93% by weight of one or more further host compounds H^B2differing from H^B.

In a preferred embodiment of the invention, the light-emitting layer B comprises up to 93% by weight of one or more solvents,

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

(i) 40-98%, more preferably 57-93%, even more preferably 74-87% by weight of the host compound H^B;

(ii) 1-50%, more preferably 5-35%, even more preferably 10-20% by weight of the TADF material E^B; and

(iii) 1-10%, more preferably 2-8%, even more preferably 3-6% by weight of the depopulation agent S^B; and optionally

(iv) 0-93% by weight of one or more further host compounds H^B2differing from H^B; and optionally

(v) 0-93% by weight of one or more solvents.

Preferably, the contents of (i) to (v) sum up to 100% by weight.

Exemplarily, the host material H^Band/or the optionally present further host compound H^B2may be selected from the group consisting of 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-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzothio-phen-2-yl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzofuranyl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzothiophenyl)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′-spirobifluorene-2-yl)-1,3,5-triazine). In one embodiment of the invention, the emission layer B comprises a so-called mixed-host system with at least one hole-dominant (n-type) host and one electron-dominant (p-type) host.

In one embodiment, the emission layer B comprises the TADF material E^Band the depopulation agent S^B, and hole-dominant host H^Bselected from the group consisting of 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-dibenzothiophenyl)phenyl]-9H-carbazole.

In a preferred embodiment, the TADF material E^Bhas a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein E^HOMO(E^B)−E^HOMO(H^B)≤0.3 eV and E^HOMO(E^B)−E^HOMO(H^B)≥−0.3 eV. In other words, the HOMO(H^B) of the host H^Bcan be higher or lower in energy compared to the HOMO(E^B) of the TADF material E^B, but the difference does not exceed 0.3 eV, more preferably does not exceed 0.2 eV.

In a preferred embodiment, the depopulation agent S^Bhas a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein E^HOMO(S^B)−E^HOMO(H^B)≤0.3 eV and E^HOMO(S^B)−E^HOMO(H^B)≥−0.3 eV. In other word, the HOMO(H^B) of the host H^Bcan be higher or lower in energy compared to the HOMO(S^B) of the depopulation agent S^B, but the difference does not exceed 0.4 eV, preferably 0.3 eV, more preferably does not exceed 0.2 eV.

In a further preferred embodiment, the TADF material E^Bhas a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B), the depopulation agent S^Bhas a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B)) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein

E^HOMO(E^B)≥E^HOMO(H^B)≥E^HOMO(S^B).

In a further embodiment, the TADF material E^Bhas a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B) the depopulation agent S^Bhas a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein E^HOMO(E^B)>E^HOMO(H^B)>E^HOMO(S^B). In this embodiment, the TADF material E^Bsignificantly participates in the hole-transport.

In a further embodiment, the TADF material E^Bhas a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B), the depopulation agent S^Bhas a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein E^HOMO(H^B)≥E^HOMO(E^B)≥E^HOMO(S^B).

In a further embodiment, the TADF material E^Bhas a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B) the depopulation agent S^Bhas a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and the host compound H^Bhas a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B), wherein E^HOMO(H^B)>E^HOMO(E^B)>E^HOMO(S^B). In this embodiment, the host significantly participates in the hole-transport.

In another embodiment, the TADF material E^Bhas a lowest unoccupied molecular orbital LUMO(E^B) having an energy E^LUMO(E^B) and the host compound H^Bhas a lowest unoccupied molecular orbital LUMO(H^B) having an energy E^LUMO(H^B), wherein E^LUMO(E^B)−E^LUMO(H^B)≤0.4 eV and E^LUMO(E^B)−E^LUMO(H^B)≥−0.4 eV. In other word, the LUMO(H^B) of the host H^Bcan be higher or lower in energy compared to the LUMO(E^B) of the TADF material E^B, but the difference does not exceed 0.4 eV, more preferably does not exceed 0.3 eV.

In a further embodiment, the TADF material E^Bhas a lowest unoccupied molecular orbital LUMO(E^B) having an energy E^LUMO(E^B) the depopulation agent S^Bhas a lowest unoccupied molecular orbital LUMO(S^B) having an energy E^LUMO(S^B) and the host compound H^Bhas a lowest unoccupied molecular orbital LUMO(H^B) having an energy E^LUMO(H^B), wherein E^LUMO(S^B)≤E^LUMO(H^B)≤E^LUMO(E^B). In a preferred embodiment, the emission layer B comprises the TADF material E^Bhaving a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B) and a lowest unoccupied molecular orbital LUMO(E^B) having an energy E^LUMO(E^B), the depopulation agent S^Bhaving a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and a lowest unoccupied molecular orbital LUMO(S^B) having an energy E^LUMO(S^B) and the host compound H^Bhaving a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B) and a lowest unoccupied molecular orbital LUMO(H^B) having an energy E^LUMO(H^B), wherein E^LUMO(S^B)≤E^LUMO(E^B)≤E^LUMO(H^B) and E^HOMO(E^B)>E^HOMO(H^B)>E^LUMO(S^B).

In a further embodiment, the emission layer B comprises the TADF material E^Bhaving a highest occupied molecular orbital HOMO(E^B) having an energy E^HOMO(E^B) and a lowest unoccupied molecular orbital LUMO(E^B) having an energy E^LUMO(E^B), the depopulation agent S^Bhaving a highest occupied molecular orbital HOMO(S^B) having an energy E^HOMO(S^B) and a lowest unoccupied molecular orbital LUMO(S^B) having an energy E^LUMO(S^B), the host compound H^Bhaving a highest occupied molecular orbital HOMO(H^B) having an energy E^HOMO(H^B) and a lowest unoccupied molecular orbital LUMO(H^B) having an energy E^LUMO(H^B) and a further host compound H^B2having a highest occupied molecular orbital HOMO(H^B2) having an energy E^HOMO(H^B2) and a lowest unoccupied molecular orbital LUMO(H^B2) having an energy E^LUMO(H^B2); wherein

E^HOMO(E^B)−E^HOMO(H^B)≤0.3 eV and E^HOMO(E^B)−E^HOMO(H^B)≥−0.3 eV;

and

E^LUMO(E^B)−E^LUMO(H^B2)≤0.4 eV and E^LUMO(E^B)−E^LUMO(H^B2)≥−0.4 eV.

In a preferred embodiment, the emission layer B comprises the TADF material E^Band depopulation agent S^B, a mixed-host system comprising T2T as electron-dominant host H^B2and a host H^Bselected from the group consisting of 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-dibenzothiophenyl)phenyl]-9H-carbazole as hole-dominant host.

The host material H^Bhas a lowermost excited singlet state energy level S1^Hand a lowermost excited triplet state energy level T1^H.

The TADF material E^Bhas a lowermost excited singlet state energy level S1^Eand a lowermost excited triplet state energy level T1^E.

The depopulation agent S^Bhas a lowermost excited singlet state energy level S1^Sand a lowermost excited triplet state energy level T1^S.

In a preferred embodiment, the lowermost excited triplet state of the host material H^Bis higher in energy than the lowermost excited triplet state of the TADF material E^B:T1^H>T1^E.

In a preferred embodiment, the lowermost excited triplet state of the host material H^Bis higher in energy than the lowermost excited triplet state of the depopulation agent S^B:T1^H>T1^S.

In a preferred embodiment, the lowermost excited singlet state of the host material H^Bis higher in energy than the lowermost excited singlet state of the TADF material E^B:S1^H>S1^E.

In a preferred embodiment, the lowermost excited singlet state of the host material H^Bis higher in energy than the lowermost excited singlet state of the depopulation agent S^B:S1^H>S1^S.

Orbital and excited state energies can be determined either by means of experimental methods known to the person skilled in the art. Experimentally, the energy of the highest occupied molecular orbital E^HOMOis determined by methods known to the person skilled in the art from cyclic voltammetry measurements with an accuracy of 0.1 eV. The energy of the lowest unoccupied molecular orbital E^LUMOis calculated as E^HOMO+E^gap, where E^gapis determined as follows: For host compounds, the onset of emission of a film with 10% by weight of host in poly(methyl methacrylate) (PMMA) is used as E^gap, unless stated otherwise. For emitter compounds, E^gapis determined as the energy at which the excitation and emission spectra of a film with 10% by weight of emitter in PMMA cross.

For host compounds, the onset of emission of a film with 10% by weight of host in poly(methyl methacrylate) (PMMA), which corresponds to the energy of the first excited singlet state S1, is used as E^gap, unless stated otherwise. For emitter compounds, E^gapand thus the energy of the first excited singlet state S1 is determined in the same way, unless stated otherwise. For host compounds, the energy of the first excited triplet state T1 is determined from the onset of the time-gated emission spectrum at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms, if not otherwise stated measured in a film of poly(methyl methacrylate) (PMMA) with 10% by weight of host. For TADF emitter compounds, the energy of the first excited triplet state T1 is determined from the onset of the time-gated emission spectrum at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms.

In the electron transport layer (ETL, any electron transporter may be used. Exemplarily, compounds poor of electrons such as, e.g., benzimidazoles, pyridines, triazoles, oxadiazoles (e.g., 1,3,4-oxadiazole), phosphinoxides and sulfone, may be used. Exemplarily, an electron transporter ETM^Dmay also be a star-shaped heterocycle such as 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi). The ETM^Dmay exemplarily be NBphen (2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline), Alq3 (Aluminum-tris(8-hydroxyquinoline)), TSPO1 (diphenyl-4-triphenylsilylphenyl-phosphinoxide), BPyTP2 (2,7-di(2,2′-bipyridin-5-yl)triphenyle), Sif87 (dibenzo[b,d]thiophen-2-yltriphenylsilane), Sif88 (dibenzo[b,d]thiophen-2-yl)diphenylsilane), BmPyPhB (1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene) and/or BTB (4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl). Optionally, the electron transport layer may be doped with materials such as Liq (8-hydroxyquinolinolatolithium). Optionally, a second electron transport layer may be located between electron transport layer and the cathode layer C.

Adjacent to the electron transport layer (ETL), a cathode layer C may be located. Exemplarily, the cathode layer C may comprise or may consist 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 consist of (essentially) intransparent 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 consist of nanoscale silver wires.

An OLED may further, optionally, comprise a protection layer between the electron transport layer (ETL) D and the cathode layer C (which may be designated as electron injection layer (EIL)). This layer may comprise lithium fluoride, caesium fluoride, silver, Liq (8-hydroxyquinolinolatolithium), Li₂O, BaF₂, MgO and/or NaF.

As used herein, if not defined more specifically in a particular context, the designation of the colors of emitted and/or absorbed light is as follows:

violet: wavelength range of >380-420 nm;

deep blue: wavelength range of >420-470 nm;

sky blue: wavelength range of >470-500 nm;

green: wavelength range of >500-560 nm;

yellow: wavelength range of >560-580 nm;

orange: wavelength range of >580-620 nm;

red: wavelength range of >620-800 nm.

With respect to emitter compounds, such colors refer to the emission maximum λmax^PMMAof a poly(methyl methacrylate) (PMMA) film with 10% by weight of the emitter. Therefore, exemplarily, a deep blue emitter has an emission maximum λmax^PMMAin the range of from 420 to 470 nm, a sky blue emitter has an emission maximum λmax^PMMAin the range of from 470 to 500 nm, a green emitter has an emission maximum λmax^PMMAin a range of from 500 to 560 nm, a red emitter has an emission maximum λmax^PMMAin a range of from 620 to 800 nm.

A deep blue emitter may preferably have an emission maximum λmax^PMMAof below 475 nm, more preferably below 470 nm, even more preferably below 465 nm or even below 460 nm. It will typically be above 420 nm, preferably above 430 nm, more preferably above 440 nm.

In one aspect of the invention, the TADF material E^Bis a deep blue emitter.

Accordingly, a further embodiment of the present invention relates to an OLED, which exhibits an external quantum efficiency at 1000 cd/m²of more than 10%, more preferably of more than 12%, more preferably of more than 15%, even more preferably of more than 17% or even more than 20% 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 exhibits a LT80 value at 500 cd/m²of more than 100 h, preferably more than 200 h, more preferably more than 400 h, even more preferably more than 750 h or even more than 1000 h.

A further embodiment of the present invention relates to an OLED, which emits light at a distinct color point. According to the present invention, the OLED emits light with a narrow emission band (small full width at half maximum (FWHM)). In a preferred embodiment, the OLED according to the invention emits light with a FWHM of the main emission peak of below 0.50 eV, more preferably of below 0.46 eV, even more preferably of below 0.43 eV or even below 0.41 eV.

A further aspect of the present invention relates to an OLED, which emits light with CIEx and CIEy color coordinates close to the CIEx (=0.131) and CIEy (=0.046) color coordinates of the primary color blue (CIEx=0.131 and CIEy=0.046) as defined by ITU-R Recommendation BT.2020 (Rec. 2020) and thus is suited for the use in Ultra High Definition (UHD) displays, e.g. UHD-TVs. In commercial applications, typically top-emitting (top-electrode is transparent) devices are used, whereas test devices as used throughout the present application represent bottom-emitting devices (bottom-electrode and substrate are transparent). The CIEy color coordinate of a blue device can be reduced by up to a factor of two, when changing from a bottom- to a top-emitting device, while the CIEx remains nearly unchanged (Okinaka et al. doi:10.1002/sdtp.10480). Accordingly, a further aspect of the present invention relates to an OLED, whose emission exhibits a CIEx color coordinate of 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 a CIEy color coordinate of 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.

In a preferred embodiment, the TADF material E^Bexhibits an emission maximum λmax^PMMA(E^B) in the range of from 450 to 470 nm (i.e., 470 nm ≥λmax^PMMA(E^B)≥450 nm).

TADF Material E^B

In a preferred embodiment, the TADF material E^Bconsists of

- a first chemical moiety comprising or consisting of a structure of Formula I:

[Image Omitted]

and

- one or two second chemical moieties comprising or consisting of a structure of Formula II:

[Image Omitted]

The first chemical moiety is linked to each of the second chemical moiety via a single bond.

Q^Iis either N or CH.

Q^IIis either N or CH.

According to the invention, at least one of Q^Iand Q^IIis N.

In one embodiment, Q^Iis N and Q^IIis CH.

In one embodiment, Q^IIis N and Q^Iis CH.

In one embodiment, Q^Iand Q^IIis each N.

T is selected from the group consisting of

the binding site of a single bond linking the first chemical moiety to the second chemical moiety, hydrogen (H), deuterium (D), and R¹.

V is selected from the group consisting of

the binding site of a single bond linking the first chemical moiety to the second chemical moiety, H, D, and R¹.

W is selected from the group consisting of

the binding site of a single bond linking the first chemical moiety to the second chemical moiety,

H, D, and R¹.

X is selected from the group consisting of

the binding site of a single bond linking the first chemical moiety to the second chemical moiety,

H, D, and R¹.

Y is selected from the group consisting of

the binding site of a single bond linking the first chemical moiety to the second chemical moiety,

H, D, and R¹.

# represents the binding site of a single bond linking the second chemical moieties to the first chemical moiety.

Z is at each occurrence independently from another selected from the group consisting of a direct bond, CR³R⁴, C═CR³R⁴, C═O, C═NR³, NR³, O, SiR³R⁴, S, S(O) and S(O)₂.

R¹is selected from the group consisting of

CN, CF₃, SiPh₃, GePh₃, and

a third chemical moiety comprising or consisting of a structure of Formula Q:

[Image Omitted]

Q¹is selected from the group consisting of N and C—R^I.

Q²is selected from the group consisting of N and C—R^II.

Q³is selected from the group consisting of N and C—R^III.

Q⁵is selected from the group consisting of N and C—R^V.

$ represents the binding site of a single bond linking the third chemical moiety to the first chemical moiety.

R^Iis selected from the group consisting of H, D, CN, CF₃, SiPh₃, GePh₃, F,

phenyl, which is optionally substituted with one or more substituents R⁶;

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶; and

a fourth chemical moiety comprising or consisting of a structure of Formula IIQ:

[Image Omitted]

§ represents the binding site of a single bond linking the fourth chemical moiety to the third chemical moiety.

Z^§ is at each occurrence independently from another selected from the group consisting of a direct bond, CR³R⁴, C═CR³R⁴, C═O, C═NR³, NR³, O, SiR³R⁴, S, S(O) and S(O)₂.

R^IIis at each occurrence independently from another selected from the group consisting of H, D, CN, CF₃, SiPh₃, GePh₃, F,

phenyl, which is optionally substituted with one or more substituents R⁶;

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶; and

a fourth chemical moiety comprising or consisting of a structure of Formula IIQ.

R^IIIis at each occurrence independently from another selected from the group consisting of H, D, CN, CF₃, SiPh₃, GePh₃, F,

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶; and

a fourth chemical moiety comprising or consisting of a structure of Formula IIQ.

R^IVis at each occurrence independently from another selected from the group consisting of H, D, CN, CF₃, SiPh₃, GePh₃, F,

phenyl, which is optionally substituted with one or more substituents R⁶;

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶.

R^Vis at each occurrence independently from another selected from the group consisting of H, D, CN, CF₃, SiPh₃, GePh₃, F,

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶.

R^a, R³and R⁴is at each occurrence independently from another selected from the group consisting of hydrogen,

deuterium, N(R⁵)₂, OR⁵, Si(R⁵)₃, B(OR⁵)₂, OSO₂R⁵, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,
- which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;
  
  C₁-C₄₀-alkoxy,
- which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;
  
  C₁-C₄₀-thioalkoxy,
- which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;
  
  C₂-C₄₀-alkenyl,
- which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;
  
  C₂-C₄₀-alkynyl,
- which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;
  
  C₆-C₆₀-aryl,
- which is optionally substituted with one or more substituents R⁵; and
  
  C₃-C₅₇-heteroaryl,
- which is optionally substituted with one or more substituents R⁵.

R⁵is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R⁶)₂, OR⁶, Si(R⁶)₃, B(OR⁶)₂, OSO₂R⁶, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₁-C₄₀-alkoxy,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₁-C₄₀-thioalkoxy,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₂-C₄₀-alkenyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₂-C₄₀-alkynyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₆-C₆₀-aryl,
- which is optionally substituted with one or more substituents R⁶; and
  
  C₃-C₅₇-heteroaryl,
- which is optionally substituted with one or more substituents R⁶.

R^fis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R^5f)₂, OR^5f, Si(R^5f)₃, B(OR^5f)₂, OSO₂R^5f, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,
- which is optionally substituted with one or more substituents R^5fand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5f═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₁-C₄₀-alkoxy,
- which is optionally substituted with one or more substituents R^5fand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5f═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₁-C₄₀-thioalkoxy,
- which is optionally substituted with one or more substituents R^5fand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5f═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₂-C₄₀-alkenyl,
- which is optionally substituted with one or more substituents R^5fand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5f═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₂-C₄₀-alkynyl,
- which is optionally substituted with one or more substituents R^5fand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5f═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₆-C₆₀-aryl,
- which is optionally substituted with one or more substituents R^5f, and
  
  C₃-C₅₇-heteroaryl,
- which is optionally substituted with one or more substituents R^5f.

R^5fis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R⁶)₂, OR⁶, Si(R⁶)₃, B(OR⁶)₂, OSO₂R⁶, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₁-C₄₀-alkoxy,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₁-C₄₀-thioalkoxy,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶;
  
  C₂-C₄₀-alkenyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶,
  
  C₂-C₄₀-alkynyl,
- which is optionally substituted with one or more substituents R⁶and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁶C═CR⁶, C≡C, Si(R⁶)₂, Ge(R⁶)₂, Sn(R⁶)₂, C═O, C═S, C═Se, C═NR⁶, P(═O)(R⁶), SO, SO₂, NR⁶, O, S or CONR⁶,
  
  C₆-C₆₀-aryl,
- which is optionally substituted with one or more substituents R⁶; and
  
  C₃-C₅₇-heteroaryl,
- which is optionally substituted with one or more substituents R⁶.

R⁶is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, CF₃, CN, F,

C₁-C₅-alkyl,
- wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF₃, or F;
  
  C₁-C₅-alkoxy,
- wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF₃, or F;
  
  C₁-C₅-thioalkoxy,
- wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF₃, or F;
  
  C₂-C₅-alkenyl,
- wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF₃, or F;
  
  C₂-C₅-alkynyl,
- wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF₃, or F;
  
  C₆-C₁₈-aryl,
- which is optionally substituted with one or more C₁-C₅-alkyl substituents;
  
  C₃-C₁₇-heteroaryl,
- which is optionally substituted with one or more C₁-C₅-alkyl substituents;
  
  N(C₆-C₁₈-aryl)₂;
  
  N(C₃-C₁₇-heteroaryl)₂; and
  
  N(C₃-C₁₇-heteroaryl)(C₆-C₁₈-aryl).

R^Tzis at each occurrence independently from another selected from the group consisting of

CN, CF₃, SiPh₃, F,

phenyl, which is optionally substituted with one or more substituents R⁶;

triazinyl, which is optionally substituted with one or more substituents R⁶;

pyridyl, which is optionally substituted with one or more substituents R⁶;

pyrimidyl, which is optionally substituted with one or more substituents R⁶.

According to the invention, the substituents R^a, R³, R⁴or R⁵independently from each other optionally form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic and/or benzo-fused ring system with one or more substituents R^a, R³, R⁴or R⁵.

According to the invention, R^for R^5findependently from each other optionally form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic and/or benzo-fused ring system with one or more substituents R^for R^5f.

According to the invention, one or two substituents selected from the group consisting of T, V, W, X, and Y represent the binding site of a single bond linking the first chemical moiety and the second chemical moiety.

According to the invention, exactly one substituent selected from the group consisting of T, V, W, X, and Y is R¹.

In a preferred embodiment, the TADF material E^Bconsists of a structure according to Formula Ia:

[Image Omitted]

wherein

for R¹, Q^Iand Q^IIthe aforementioned definitions apply.

T # is selected from the group consisting of the binding site of a single bond linking the first chemical moiety to the second chemical moiety, H, D, and R¹.

W # is selected from the group consisting of the binding site of a single bond linking to the first chemical moiety to the second chemical moiety, H, D, and R¹.

According to the invention, exactly one substituent selected from the group consisting of T # and W # represents the binding site of a single bond linking the first chemical moiety and the second chemical moiety.

In one embodiment, T represents the binding site of a single bond linking the first chemical moiety and to the second chemical moiety.

In one embodiment, W represents the binding site of a single bond linking the first chemical moiety and to the second chemical moiety.

In one embodiment, the fourth chemical moiety comprising or consisting of a structure of Formula IIQ is identical to the one or two second chemical moieties comprising or consisting of a structure of Formula II.

In one embodiment, the fourth chemical moiety comprising or consisting of a structure of Formula IIQ is different to the one or two second chemical moieties comprising or consisting of a structure of Formula II.

In a preferred embodiment, Z is a direct bond at each occurrence.

In a preferred embodiment, the TADF material E^Bconsists of a structure according to Formula III:

[Image Omitted]

wherein

wherein R¹is selected from the group consisting of structures according to Formulas A1 to A27:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In one embodiment, the TADF material E^Bconsists of a structure according to Formula IV:

[Image Omitted]

wherein R¹is selected is selected from the group consisting of structures according to Formulas A1 to A27:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In one embodiment, the TADF material E^Bconsists of a structure according to Formula V:

[Image Omitted]

wherein R¹is selected form the group consisting of structures according to Formulas B1 to B9:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In one embodiment, the TADF material E^Bconsists of a structure according to Formula VI:

[Image Omitted]

wherein R¹is selected form the group consisting of structures according to Formulas B1 to B9:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In one embodiment, the TADF material E^Bconsists of a structure according to Formula VII:

[Image Omitted]

wherein R¹is selected form the group consisting of structures according to Formulas D1 to D9:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In one embodiment, the TADF material E^Bconsists of a structure according to Formula VIII:

[Image Omitted]

wherein R¹is selected form the group consisting of structures according to Formulas D1 to D9:

[Image Omitted]

wherein & represents the binding site of a single bond linking R¹to the first chemical moiety.

In a further embodiment of the invention, the one or two second chemical moieties comprise or consist of a structure of Formula IIa:

[Image Omitted]

wherein # and R^aare defined as described above.

In a further embodiment of the invention, R^ais at each occurrence independently from another selected from the group consisting of

hydrogen,

Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

and N(Ph)₂.

In a further embodiment of the invention, R^ais at each occurrence independently from another selected from the group consisting of

hydrogen, Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph, and

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph.

In a further embodiment of the invention, the one or two second chemical moieties comprise or consist of a structure of Formula Ilb, a structure of Formula IIb-2, a structure of Formula IIb-3 or a structure of Formula IIb-4:

[Image Omitted]

R^bis at each occurrence independently from another selected from the group consisting of N(R⁵)₂,

OR⁵, Si(R⁵)₃, B(OR⁵)₂, OSO₂R⁵, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,

which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;

C₁-C₄₀-alkoxy,

which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;

C₁-C₄₀-thioalkoxy,

which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;

C₂-C₄₀-alkenyl,

which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;

C₂-C₄₀-alkynyl,

which is optionally substituted with one or more substituents R⁵and wherein one or more non-adjacent CH₂-groups are optionally substituted by R⁵C═CR⁵, C≡C, Si(R⁵)₂, Ge(R⁵)₂, Sn(R⁵)₂, C═O, C═S, C═Se, C═NR⁵, P(═O)(R⁵), SO, SO₂, NR⁵, O, S or CONR⁵;

C₆-C₆₀-aryl,

which is optionally substituted with one or more substituents R⁵; and C₃-C₅₇-heteroaryl,

which is optionally substituted with one or more substituents R⁵.

For additional variables, the aforementioned definitions apply.

In one additional embodiment of the invention, the one or two second chemical moieties comprise or consist of a structure of Formula IIc, a structure of Formula IIc-2, a structure of Formula IIc-3 or a structure of Formula IIc-4:

[Image Omitted]

wherein the aforementioned definitions apply.

In a further embodiment of the invention, R^bis at each occurrence independently from another selected from the group consisting of

Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

and N(Ph)₂.

In a further embodiment of the invention, R^bis at each occurrence independently from another selected from the group consisting of

Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph, and

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph.

In the following, examples of the second chemical moiety are shown:

[Image Omitted]

For each of the above-given second chemical moieties, the aforementioned definitions apply for #, Z, R^a, R³, R⁴and R⁵.

In one embodiment, R^aand R⁵is at each occurrence independently from another selected from the group consisting of hydrogen (H), methyl (Me), i-propyl (CH(CH₃)₂) (ⁱPr), t-butyl (^tBu), phenyl (Ph),

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph; and

diphenylamine (NPh₂).

In a further embodiment of the invention, the fourth chemical moiety comprises or consists of a structure of Formula IIq:

[Image Omitted]

wherein § and R^fare defined as above.

In a further embodiment of the invention, R^fis at each occurrence independently from another selected from the group consisting of

hydrogen, Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

and N(Ph)₂.

In a further embodiment of the invention, R^fis at each occurrence independently from another selected from the group consisting of

hydrogen, Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph, and

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph.

In a further embodiment of the invention, the fourth chemical moiety comprises or consists of a structure of Formula IIbq, a structure of Formula IIbq-2, a structure of Formula IIbq-3 or a structure of Formula IIbq-4:

[Image Omitted]

R^bqis at each occurrence independently from another selected from the group consisting of N(R^5f)₂, OR^5f, Si(R^5f)₃, B(OR^5f)₂, OSO₂R^5f, CF₃, CN, F, Br, I,

C₁-C₄₀-alkyl,

- which is optionally substituted with one or more substituents R^5fand
- wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5fC═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₁-C₄₀-alkoxy,
- which is optionally substituted with one or more substituents R^5fand
- wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5fC═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₁-C₄₀-thioalkoxy,
- which is optionally substituted with one or more substituents R^5fand
- wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5fC═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₂-C₄₀-alkenyl,
- which is optionally substituted with one or more substituents R^5fand
- wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5fC═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f; C₂-C₄₀-alkynyl,
- which is optionally substituted with one or more substituents R^5fand
- wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5fC═CR^5f, C≡C, Si(R^5f)₂, Ge(R^5f)₂, Sn(R^5f)₂, C═O, C═S, C═Se, C═NR^5f, P(═O)(R^5f), SO, SO₂, NR^5f, O, S or CONR^5f;
  
  C₆-C₆₀-aryl,
- which is optionally substituted with one or more substituents R^5f, and
  
  C₃-C₅₇-heteroaryl,
- which is optionally substituted with one or more substituents R^5f.

For additional variables, the aforementioned definitions apply.

In one additional embodiment of the invention, the fourth chemical moiety comprises or consists of a structure of Formula IIcq, a structure of Formula IIcq-2, a structure of Formula IIcq-3 or a structure of Formula IIcq-4:

[Image Omitted]

wherein the aforementioned definitions apply.

In a further embodiment of the invention, R^bqis at each occurrence independently from another selected from the group consisting of

Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph,

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph,

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph,

and N(Ph)₂.

In a further embodiment of the invention, R^bqis at each occurrence independently from another selected from the group consisting of

Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph,

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph,

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph, and

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, C_F3, and Ph.

In one embodiment of the invention, R^bqis at each occurrence independently from another selected from the group consisting of

Me, ⁱPr, ^tBu,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph; and

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, C_N, CF₃and Ph.

In the following, exemplary embodiments of the fourth chemical moiety are shown:

[Image Omitted]

For $, R^f, and R^5fof the fourth chemical moiety shown above, the aforementioned definitions apply.

In one embodiment, R^afand R^5fis at each occurrence independently from another selected from the group consisting of hydrogen (H), methyl (Me), i-propyl (CH(CH₃)₂) (ⁱPr), t-butyl (^tBu), phenyl (Ph),

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃, and Ph; and

diphenylamine (NPh₂).

The synthesis of the molecules of a structure of Formula I can be accomplished via standard reactions and reaction conditions known to the skilled artesian. Typically, in a first step a coupling reaction, preferably a palladium catalyzed coupling reaction, is performed.

General synthesis scheme for the TADF material E^B:

[Image Omitted]

General procedure for synthesis AAV1:

[Image Omitted]

Z1 (e.g. 2-chloro-4,6-bisphenyl-1,3,5-triazine) (1.00 equivalents) R¹-fluoro-phenylboronic ester (1.00-1.50 equivalents), Pd(PPh₃)₄(tetrakis(triphenylphosphine)palladium(0) (CAS:14221-01-3, 0.10 equivalents) and potassium carbonate (3.00 equivalents) are stirred overnight under nitrogen atmosphere in THF/Water (3:1) at 70° C. After cooling down to room temperature (RT), the reaction mixture is extracted with ethyl acetate/brine. The organic phases are collected, the organic solvent is removed and the crude product Z0 is purified by flash chromatography or by recrystallization.

General procedure for synthesis AAV3:

[Image Omitted]

Z0 (1 equivalent), the corresponding donor molecule D-H (n equivalents, i.e. 1 equivalent or 2 equivalents, depending on the integer n) and tribasic potassium phosphate (3.00 equivalents) are suspended under nitrogen atmosphere in DMSO and stirred at 120° C. for 12 to 16 hours. Subsequently, the reaction mixture is poured into an excess of water in order to precipitate the product. The precipitate is filtered off, washed with water and dried under vacuum. The crude product is purified by recrystallization or by flash chromatography. The product is obtained as a solid.

In particular, the donor molecule D-H 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).

For example, a halogen-substituted carbazole, particularly 3-bromocarbazole, can be used as D-H.

In a subsequent reaction, a boronic acid ester functional group or boronic acid functional group may be, for example, introduced at the position of the one or more halogen substituents, which was introduced via D-H, to yield the corresponding carbazol-3-ylboronic acid ester or carbazol-3-ylboronic acid, e.g., via the reaction with bis(pinacolato)diboron (CAS No. 73183-34-3). Subsequently, one or more substituents R^amay be introduced at the position of the boronic acid ester group or the boronic acid group via a coupling reaction with the corresponding halogenated reactant R^a-Hal, preferably R^a—Cl and R^a—Br. Alternatively, one or more substituents R^amay be introduced at the position of the one or more halogen substituents, which was introduced via D-H, via the reaction with a boronic acid of the substituent R^a[R^a—B(OH)₂] or a corresponding boronic acid ester.

Depopulation Agent S^B

In a preferred embodiment, the depopulation agent S^Bconsists of a structure according to Formula 1s:

[Image Omitted]

n is at each occurrence independently from another 1 or 2.

X^sis at each occurrence independently from another selected CN or CF₃.

Ar^EWGis at each occurrence independently from another a structure according to one of Formulas IIsa to IIsm:

[Image Omitted]

wherein #^srepresents the binding site of the single bond linking Ar^EWGto the substituted central phenyl ring of Formula 1 s.

R^tis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, C₁-C₅-alkyl, wherein one or more hydrogen atoms are optionally substituted by deuterium, and C₆-C₁₈-aryl, which is optionally substituted with one or more substituents R^6s.

R^sis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R^5s)₂, OR^5s,

- SR^5s, Si(R^5s)₃, CF₃, CN, F,
- C₁-C₄₀-alkyl which is optionally substituted with one or more substituents R^5sand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5s═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;
- C₁-C₄₀-thioalkoxy which is optionally substituted with one or more substituents R^5sand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5s═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; and
- C₆-C₆₀-aryl which is optionally substituted with one or more substituents R^5s;
- C₃-C₅₇-heteroaryl which is optionally substituted with one or more substituents R^5s.

R^5sis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R^6s)₂, OR^6s, SR^6s, Si(R^6s)₃, CF₃, CN, F,

- C₁-C₄₀-alkyl which is optionally substituted with one or more substituents R^6sand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^6sC═CR^6s, C≡C, Si(R^6s)₂, Ge(R^6s)₂, Sn(R^6s)₂, C═O, C═S, C═Se, C═NR^6s, P(═O)(R^6s), SO, SO₂, NR^6s, O, S or CONR^6s;
- C₆-C₆₀-aryl which is optionally substituted with one or more substituents R^6s; and
- C₃-C₅₇-heteroaryl which is optionally substituted with one or more substituents R^6s.

R^6sis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, CF₃, CN, F,

- C₁-C₅-alkyl, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF₃, or F;
- C₁-C₅-alkoxy,
- wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF₃, or F;
- C₁-C₅-thioalkoxy, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF₃, or F;
- C₆-C₁₈-aryl which is optionally substituted with one or more C₁-C₅-alkyl substituents;
- C₃-C₁₇-heteroaryl which is optionally substituted with one or more C₁-C₅-alkyl substituents;
- N(C₆-C₁₈-aryl)₂;
- N(C₃-C₁₇-heteroaryl)₂, and
- N(C₃-C₁₇-heteroaryl)(C₆-C₁₈-aryl).

R^dis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R^5s)₂, OR^5s,

- SR^5s, Si(R^5s)₃, CF₃, CN, F,
- C₁-C₄₀-alkyl which is optionally substituted with one or more substituents R^5sand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5s═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;
- C₁-C₄₀-thioalkoxy which is optionally substituted with one or more substituents R^5sand wherein one or more non-adjacent CH₂-groups are optionally substituted by R^5s═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; and
- C₆-C₆₀-aryl which is optionally substituted with one or more substituents R^5s;
- C₃-C₅₇-heteroaryl which is optionally substituted with one or more substituents R^5ss.

According to the invention, the substituents R^sor R^5smay independently from each other optionally form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic and/or benzo-fused ring system with one or more substituents R^sor R^5s.

According to the invention, the one or more substituents R^dindependently from each other optionally may form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic and/or benzo-fused ring system with one or more substituents R^d.

In one embodiment of the invention, n=2.

In one embodiment of the invention, X^sis CN.

In a preferred embodiment, n=2 and X^sis CN.

In one embodiment of the invention, R^sis at each occurrence independently from another selected from the group consisting of

hydrogen, deuterium, Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph; and

N(Ph)₂.

In one embodiment of the invention, R^dis at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, Me, ⁱPr, ^tBu, CN, CF₃,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph;

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, ⁱPr, ^tBu, CN, CF₃and Ph; and N(Ph)₂.

In one embodiment of the invention, depopulation agent S^Bis chosen from molecules of a structure of Formula IIIs:

[Image Omitted]

wherein R^s, Ar^EWGand X^sare defined as above.

In one embodiment of the invention, depopulation agent S^Bis chosen from molecules of a structure of Formula IIIas:

[Image Omitted]

wherein R^sand Ar^EWGare defined as above.

In one embodiment of the invention, the depopulation agent S^Bis chosen from molecules of a structure of Formula IIIaas:

[Image Omitted]