Organic electroluminescent device emitting blue light

1. An organic electroluminescent device comprising 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 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 B emits 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:

S 1 S ≥S 1 E   (1)

T 1 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), and

wherein the mass ratio of TADF material to depopulation agent (E B :S B ) is >1.

2. The organic electroluminescent device according to claim 1 , the TADF material E B is characterized in that it has a ΔE ST value, which corresponds to the energy difference between S1 E and T1 E , of less than 0.4 eV.

3. The organic electroluminescent device according to claim 1 , wherein said 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.

4. The organic electroluminescent device according to claim 1 , wherein the TADF material E B is an organic TADF emitter or a combination of two or more organic TADF emitters.

5. The organic electroluminescent device according to claim 1 , wherein the depopulation agent S B is an organic TADF emitter or a combination of two or more organic TADF emitters.

6. The organic electroluminescent device according to claim 1 , wherein the relation expressed by the following formula (5a) or (5b) applies:

E HOMO ( E B )> E HOMO ( H B )  (5a)

E HOMO ( E B )< E HOMO ( H B )  (5b).

7. The organic electroluminescent device according to claim 1 , wherein the relation expressed by the following formula (6) applies:

E HOMO ( S B )< E HOMO ( H B )  (6).

8. The organic electroluminescent device according to claim 1 , wherein the device exhibits an emission maximum λ max (D) of 440 to 480 nm.

9. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer B comprises:

(i) 40-98% by weight of the host material H B ;

(ii) 1-50% by weight of the TADF material E B ; and

(iii) 1-10% by weight of the depopulation agent S B ; and optionally

(iv) 0-58% by weight of one or more further host materials H B2 differing from H B ; and optionally

(v) 0-58% by weight of one or more solvents.

10. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer B comprises the depopulation agent S B in 2-8% by weight.

11. The organic electroluminescent device according to claim 1 , wherein the TADF material E B comprises

a first chemical moiety comprising a structure of Formula I,

and

one or two second chemical moieties comprising a structure of Formula II,

wherein the first chemical moiety is linked to each of the second chemical moiety via a single bond;

Q I is either N or CH;

Q II is either N or CH;

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 R 1 ;

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 R 1 ;

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 R 1 ;

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 R 1 ;

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 R 1 ;

# represents the binding site of a single bond linking the one or two 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, 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 ;

R 1 is selected from the group consisting of

CN,

CF 3 ,

SiPh 3 ,

GePh 3 , and

a third chemical moiety comprising a structure of Formula Q:

wherein

Q 1 is selected from the group consisting of N and C—R I ;

Q 2 is selected from the group consisting of N and C—R II ;

Q 3 is selected from the group consisting of N and C—R III ;

Q 5 is selected from the group consisting of N and C—R V ; and

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

R I is selected from the group consisting of

H,

D,

CN,

CF 3 ,

SiPh 3 ,

GePh 3 ,

F,

phenyl, which is optionally substituted with one or more substituents R 6 ;

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ; and

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

§ 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, 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 ;

R II is at each occurrence independently from another selected from the group consisting of

H,

D,

CN,

CF 3 ,

SiPh 3 ,

GePh 3 ,

F,

phenyl, which is optionally substituted with one or more substituents R 6 ;

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ; and

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

R III is at each occurrence independently from another selected from the group consisting of

H,

D,

CN,

CF 3 ,

SiPh 3 ,

GePh 3 ,

F,

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ; and

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

R IV is at each occurrence independently from another selected from the group consisting of

H,

D,

CN,

CF 3 ,

SiPh 3 ,

GePh 3 ,

F,

phenyl, which is optionally substituted with one or more substituents R 6 ;

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ;

R V is at each occurrence independently from another selected from the group consisting of

H,

D,

CN,

CF 3 ,

SiPh 3 ,

GePh 3 ,

F,

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ;

R a , R 3 , and R 4 is at each occurrence independently from another selected from the group consisting of

hydrogen,

deuterium,

N(R 5 ) 2 ,

OR 5 ,

Si(R 5 ) 3 ,

B(OR 5 ) 2 ,

OSO 2 R 5 ,

CF 3 ,

CN,

F,

Br,

I,

C 1 -C 40 -alkyl,

which is optionally substituted with one or more substituents R 5 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5 , O, S, or CONR 5 ;

C 1 -C 40 -alkoxy,

which is optionally substituted with one or more substituents R 5 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5 , O, S, or CONR 5 ;

C 1 -C 40 -thioalkoxy,

which is optionally substituted with one or more substituents R 5 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5 , O, S, or CONR 5 ;

C 2 -C 40 -alkenyl,

which is optionally substituted with one or more substituents R 5 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5 , O, S, or CONR 5 ;

C 2 -C 40 -alkynyl,

which is optionally substituted with one or more substituents R 5 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5 , O, S, or CONR 5 ;

C 6 -C 60 -aryl,

which is optionally substituted with one or more substituents R 5 ; and

C 3 -C 57 -heteroaryl,

which is optionally substituted with one or more substituents R 5 ;

R 5 is at each occurrence independently from another selected from the group consisting of

hydrogen,

deuterium,

N(R 6 ) 2 ,

OR 6 ,

Si(R 6 ) 3 ,

B(OR 6 ) 2 ,

OSO 2 R 6 ;

CF 3 , CN, F, Br, I,

C 1 -C 40 -alkyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 1 -C 40 -alkoxy,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 1 -C 40 -thioalkoxy,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 2 -C 40 -alkenyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 2 -C 40 -alkynyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 6 -C 60 -aryl,

which is optionally substituted with one or more substituents R 6 ; and

C 3 -C 57 -heteroaryl,

which is optionally substituted with one or more substituents R 6 ;

R f is 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 ,

OSO 2 R 5f ,

CF 3 ,

CN,

F, Br, I,

C 1 -C 40 -alkyl,

which is optionally substituted with one or more substituents R 5f and

wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 5f C═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, SO 2 , NR 5 , O, S, or CONR 5f ;

C 1 -C 40 -alkoxy,

which is optionally substituted with one or more substituents R 5f and

wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 5f C═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, SO 2 , NR 5 , O, S, or CONR 5f ;

C 1 -C 40 -thioalkoxy,

which is optionally substituted with one or more substituents R 5f and

wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 5f C═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, SO 2 , NR 5 , O, S, or CONR 5f ;

C 2 -C 40 -alkenyl,

which is optionally substituted with one or more substituents R 5f and

wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 5f C═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, SO 2 , NR 5 , O, S, or CONR 5f ;

C 2 -C 40 -alkynyl,

which is optionally substituted with one or more substituents R 5f and

wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 5f C═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, SO 2 , NR 5 , O, S, or CONR 5f ;

C 6 -C 60 -aryl,

which is optionally substituted with one or more substituents R 5f ; and

C 3 -C 57 -heteroaryl,

which is optionally substituted with one or more substituents R 5f ;

R 5f is at each occurrence independently from another selected from the group consisting of hydrogen,

deuterium,

N(R 6 ) 2 ,

OR 6 ,

Si(R 6 ) 3 ,

B(OR 6 ) 2 ,

OSO 2 R 6 ,

CF 3 ,

CN,

F, Br, I,

C 1 -C 40 -alkyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 1 -C 40 -alkoxy,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 1 -C 40 -thioalkoxy,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 2 -C 40 -alkenyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 2 -C 40 -alkynyl,

which is optionally substituted with one or more substituents R 6 and

wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 6 , O, S, or CONR 6 ;

C 6 -C 60 -aryl,

which is optionally substituted with one or more substituents R 6 ; and

C 3 -C 57 -heteroaryl,

which is optionally substituted with one or more substituents R 6 ;

R 6 is at each occurrence independently from another selected from the group consisting of

hydrogen,

deuterium,

OPh,

CF 3 ,

CN,

F,

C 1 -C 5 -alkyl,

wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF 3 , or F;

C 1 -C 5 -alkoxy,

wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF 3 , or F;

C 1 -C 5 -thioalkoxy,

wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF 3 , or F;

C 2 -C 5 -alkenyl,

wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF 3 , or F;

C 2 -C 5 -alkynyl,

wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF 3 , or F;

C 6 -C 18 -aryl,

which is optionally substituted with one or more C 1 -C 5 -alkyl substituents;

C 3 -C 17 -heteroaryl,

which is optionally substituted with one or more C 1 -C 5 -alkyl substituents;

N(C 6 -C 18 -aryl) 2 ;

N(C 3 -C 17 -heteroaryl) 2 ; and

N(C 3 -C 17 -heteroaryl)(C 6 -C 18 -aryl);

R Tz is at each occurrence independently from another selected from the group consisting of

CN, CF 3 , SiPh 3 , F,

phenyl, which is optionally substituted with one or more substituents R 6 ;

triazinyl, which is optionally substituted with one or more substituents R 6 ;

pyridyl, which is optionally substituted with one or more substituents R 6 ;

pyrimidyl, which is optionally substituted with one or more substituents R 6 ;

wherein the substituents R a , R 3 , R 4 , or R 5 independently from each other optionally form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic, benzo-fused ring system, or a combination thereof with one or more substituents R a , R 3 , R 4 , or R 5 ;

wherein the substituents R f or R 5f independently from each other optionally form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic, benzo-fused ring system, or a combination thereof with one or more substituents R f or R 5f ;

wherein at least one of Q I and Q II is N;

wherein 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;

wherein exactly one substituent selected from the group consisting of T, V, W, X, and Y is R 1 .

12. The organic electroluminescent device according to claim 11 , wherein the TADF material E B consists of a structure of Formula Ia:

wherein

R 1 , Q I , and Q II are defined as in claim 11 ;

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 R 1 ;

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 R 1 ;

wherein 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.

13. The organic electroluminescent device according to claim 11 , wherein Z is a direct bond at each occurrence.

14. The organic electroluminescent device according to claim 11 , wherein R a is at each occurrence independently from another selected from the group consisting of

hydrogen, deuterium, Me, i Pr, t Bu, CN, CF 3 ,

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph; and

N(Ph) 2 .

15. The organic electroluminescent device according to claim 1 , wherein the depopulation agent S B consists of a structure according to Formula 1s

wherein

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

X s is at each occurrence independently from another selected CN or CF 3 ;

Ar EWG is at each occurrence independently from another a structure according to one of Formulas IIsa to IIsm

wherein # s represents the binding site of the single bond linking Ar EWG to the substituted central phenyl ring of Formula 1s;

R t is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, C 1 -C 5 -alkyl, wherein one or more hydrogen atoms are optionally substituted by deuterium, and C 6 -C 18 -aryl, which is optionally substituted with one or more substituents R 6s ;

R s is 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 , CF 3 , CN, F,

C 1 -C 40 -alkyl which is optionally substituted with one or more substituents R 5s and wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5s , O, S, or CONR 5s ;

C 1 -C 40 -thioalkoxy which is optionally substituted with one or more substituents R 5s and wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5s , O, S, or CONR 5s ; and

C 6 -C 60 -aryl which is optionally substituted with one or more substituents R 5s ;

C 3 -C 57 -heteroaryl which is optionally substituted with one or more substituents R 5s ;

R 5s is 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 , CF 3 , CN, F,

C 1 -C 40 -alkyl which is optionally substituted with one or more substituents R 6s and wherein one or more non-adjacent CH 2 -groups are optionally substituted by R 6s C═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, SO 2 , NR 6s , O, S, or CONR 6s ;

C 6 -C 60 -aryl which is optionally substituted with one or more substituents R 6s ; and

C 3 -C 57 -heteroaryl which is optionally substituted with one or more substituents R 6s ;

R 6s is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, CF 3 , CN, F;

C 1 -C 5 -alkyl, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF 3 , or F;

C 1 -C 5 -alkoxy, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF 3 , or F;

C 1 -C 5 -thioalkoxy, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF 3 , or F;

C 6 -C 18 -aryl which is optionally substituted with one or more C 1 -C 5 -alkyl substituents;

C 3 -C 17 -heteroaryl which is optionally substituted with one or more C 1 -C 5 -alkyl substituents;

N(C 6 -C 18 -aryl) 2 ;

N(C 3 -C 17 -heteroaryl) 2 ; and

N(C 3 -C 17 -heteroaryl)(C 6 -C 18 -aryl);

R d is 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 , CF 3 , CN, F,

C 1 -C 40 -alkyl which is optionally substituted with one or more substituents R 5s and wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5s , O, S, or CONR 5s ;

C 1 -C 40 -thioalkoxy which is optionally substituted with one or more substituents RSs and wherein one or more non-adjacent CH 2 -groups are optionally substituted 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, SO 2 , NR 5s , O, S, or CONR 5s ; and

C 6 -C 60 -aryl which is optionally substituted with one or more substituents R 5s ; C 3 -C 57 -heteroaryl which is optionally substituted with one or more substituents R 5s ;

wherein the substituents R s or R 5s independently from each other optionally may form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic, benzo-fused ring system, or a combination thereof with one or more substituents R s or R 5s ; and

wherein the one or more substituents R d independently from each other optionally may form a mono- or polycyclic, (hetero)aliphatic, (hetero)aromatic benzo-fused ring system, or a combination thereof with one or more substituents R d .

16. The organic electroluminescent device according to claim 15 , wherein n=2 and X s is CN.

17. The organic electroluminescent device according to claim 15 , wherein R s is at each occurrence independently from another selected from the group consisting of

hydrogen, deuterium, Me, i Pr, t Bu, CN, CF 3 ;

Ph, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

pyridinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

pyrimidinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

carbazolyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph;

triazinyl, which is optionally substituted with one or more substituents independently from each other selected from the group consisting of Me, i Pr, t Bu, CN, CF 3 , and Ph; and

N(Ph) 2 .