ORGANIC ELECTROLUMINESCENT DEVICE EMITTING VISIBLE LIGHT
The invention relates to an organic electroluminescent device comprising a light-emitting layer B comprising a host material H B , a thermally activated delayed fluorescence (TADF) material E B , and a depopulation agent S B .
1 - 16 . (canceled)
17 . An organic electroluminescent device comprising a light-emitting layer B comprising:
(i) a host material H B , which has a lowermost excited singlet state energy level S1 H , a lowermost excited triplet state energy level T1 H , 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 , and a highest occupied molecular orbital HOMO(E B ) having an energy E HOMO (E B ); and
(iii) a depopulation agent S B , which has a lowermost excited singlet state energy level S1 S , optionally a lowermost excited triplet state energy level T1 S , 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 (3) and either (4a) and (4b), or (5a) and (5b) apply:
S 1 H >S 1 E (1)
S 1 H >S 1 S (2)
S 1 S >S 1 E (3)
E HOMO ( E B )≤ E HOMO ( H B ) (4a)
0.2 eV≤ E HOMO ( S B )− E HOMO ( E B )≤0.8 eV (4b)
E HOMO ( H B )≥ E HOMO ( E B ) (5a)
0.2 eV≤ E HOMO ( S B )− E HOMO ( H B )≤0.8 eV (5b).
18 . The organic electroluminescent device according to claim 17 , wherein the TADF material E B has a ΔE ST value, which corresponds to the energy difference between S1 E and T1 E , of less than 0.4 eV.
19 . The organic electroluminescent device according to claim 17 , wherein the mass ratio of the TADF material E B to depopulation agent S B (E B :S B ) is >1.
20 . The organic electroluminescent device according to claim 17 , wherein the organic electroluminescent device is selected from the group consisting of an organic light emitting diode, a light emitting electrochemical cell, and a light-emitting transistor.
21 . The organic electroluminescent device according to claim 17 , wherein the TADF material E B is an organic TADF emitter or a combination of two or more organic TADF emitters.
22 . The organic electroluminescent device according to claim 17 , wherein the depopulation agent S B is an organic TADF emitter or a combination of two or more organic TADF emitters.
23 . The organic electroluminescent device according to claim 17 , wherein the relation between the lowest unoccupied molecular orbital LUMO(E B ) of the TADF material E B having an energy E LUMO (E B ) and the lowest unoccupied molecular orbital LUMO(S B ) of the depopulation agent S B having an energy E LUMO (S B ) expressed by formula (7) applies:
E LUMO ( S B )> E LUMO ( E B ) (7).
24 . The organic electroluminescent device according to claim 17 , wherein a relation expressed by formula (6a), (6b), or (6c) applies:
E HOMO ( E B )> E HOMO ( H B ) (6a)
E HOMO ( H B )> E HOMO ( E B ) (6b)
−0.2 eV≤ E HOMO ( H B )− E HOMO ( E B )≤0.2 eV (6c).
25 . The organic electroluminescent device according to claim 17 , wherein the light-emitting layer B comprises:
(i) 39.8-98% by weight of the host compound H B ;
(ii) 0.1-50% by weight of the TADF material E B ; and
(iii) 0.1-50% by weight of depopulation agent S B ; and optionally
(iv) 0-60% by weight of one or more further host compounds H B2 differing from H B ; and optionally
(v) 0-60% by weight of one or more solvents; and optionally
(vi) 0-30% by weight of at least one further emitter molecule F.
26 . The organic electroluminescent device according to claim 17 , wherein the light-emitting layer B comprises 1-8% by weight of the depopulation agent S B .
27 . The organic electroluminescent device according to claim 17 , wherein the depopulation agent S B has a ΔE ST value, which corresponds to the energy difference between S1 S and T1 S , of less than 0.4 eV.
28 . The organic electroluminescent device according to claim 17 , wherein the TADF emitter E B and/or the depopulation agent S B comprises or consists of a structure according to Formula I-TADF
wherein:
is at each occurrence independently from another 1 or 2;
p is at each occurrence independently from another 1 or 2;
X is at each occurrence independently from another selected from the group consisting of Ar EWG H, CN, and CF 3 ;
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 ;
Ar EWG is at each occurrence independently from another a structure according to one of Formulas IIa to IIk
wherein # represents the binding site of the single bond linking Ar EWG to the substituted central phenyl ring of Formula I-TADF;
R 1 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 6 ;
R 2 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 6 ;
R a , R 3 , and R 4 are at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R 5 ) 2 , OR 5 ,
SR 5 , Si(R 5 ) 3 , CF 3 , CN, F,
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 -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 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 , SR 6 , Si(R 6 ) 3 , CF 3 , CN, F,
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 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 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 6 -C 18 -aryl substituents and/or 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 5 ) 2 , OR 5 ,
SR 5 , Si(R 5 ) 3 , CF 3 , CN, F,
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 -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 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 ;
wherein the substituents R a , R 3 , R 4 , or R 5 independently from each other may optionally form a mono- or polycyclic, aliphatic, aromatic, and/or benzo-fused ring system with one or more other substituents R a , R 3 , R 4 , or R 5 ; and
wherein the one or more substituents R d independently from each other may optionally form a mono- or polycyclic, aliphatic, aromatic, and/or benzo-fused ring system with one or more other substituents R d .
29 . The organic electroluminescent device according to claim 17 , wherein depopulation agent S B comprises or consists of a structure according to Formula I-NRCT:
wherein:
o is 0 or 1;
m=1−o;
X 1 is N or B;
X 2 is N or B;
X 3 is N or B;
W is selected from the group consisting of Si(R 3S ) 2 , C(R 3S ) 2 , and BR 3S ;
each of R 1S , R 2S , and R 3S is independently from each other selected from the group consisting of:
C 1 -C 5 -alkyl,
which is optionally substituted with one or more substituents R 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 ;
each of R I , R II , R III , R IV , R V , R VI , R VII , R VIII , R IX , R X , and R XI is independently from another selected from the group consisting of:
hydrogen, deuterium, N(R 5S ) 2 , OR 5S , Si(R 5S ) 3 , B(OR 5S ) 2 , OSO 2 R 5S , CF 3 , CN, halogen,
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 each optionally substituted by R 55 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 -alkoxy,
which is optionally substituted with one or more substituents R 5S , and
wherein one or more non-adjacent CH 2 -groups are each 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 each 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 2 -C 40 -alkenyl,
which is optionally substituted with one or more substituents R 5S , and
wherein one or more non-adjacent CH 2 -groups are each 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 2 -C 40 -alkynyl,
which is optionally substituted with one or more substituents R 5S , and
wherein one or more non-adjacent CH 2 -groups are each 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 5 S, O, S, or CONR 5S ;
C 6 -C 60 -aryl,
which is optionally substituted with one or more substituents R 5S ; and
C 3 -C 57 -heteroaryl,
which is optionally substituted with one or more substituents RSS;
R 5S 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 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 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 15 -aryl) 2 ;
N(C 3 -C 17 -heteroaryl) 2 ; and
N(C 3 -C 17 -heteroaryl)(C 6 -C 15 -aryl);
wherein two or more of the substituents selected from the group consisting of R I , R II , R III , R IV , R V , R VI , R VII , R VIII , R IX , R X , and R XI that are positioned adjacent to another may optionally each form a mono- or polycyclic, aliphatic, aromatic, and/or benzo-fused ring system with another; and
wherein at least one of X 1 , X 2 , and X 3 is B and at least one of X 1 , X 2 , and X 3 is N.
30 . A method for generating visible light comprising the steps of:
(i) providing an organic electroluminescent device according to claim 17 ; and
(ii) applying an electrical current to the organic electroluminescent device.
31 . A thermally activated delayed fluorescence (TADF) material E B in combination with at least one host material H B and at least one depopulation agent S B in a light-emitting layer for increasing the lifetime of the organic electroluminescent device.
32 . The TADF material E B in combination with at least one host material H B and at least one depopulation agent S B in a light-emitting layer of claim 31 , wherein:
(i) the host material H B has a lowermost excited singlet state energy level S1 H , a lowermost excited triplet state energy level T1 H , and a highest occupied molecular orbital HOMO(H B ) having an energy E HOMO (H B );
(ii) the TADF material E B has a lowermost excited singlet state energy level S1 E , a lowermost excited triplet state energy level T1 E , and a highest occupied molecular orbital HOMO(E B ) having an energy E HOMO (E B ); and
(iii) the depopulation agent S B has a lowermost excited singlet state energy level S1 S , optionally a lowermost excited triplet state energy level T1 S , 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 (3) and either (4a) and (4b), or (5a) and (5b) apply:
S 1 H >S 1 E (1)
S 1 H >S 1 S (2)
S 1 S >S 1 E (3)
E HOMO ( E B )≤ E HOMO ( H B ) (4a)
0.2 eV≤ E HOMO ( S B )− E HOMO ( E B )≤0.8 eV (4b)
E HOMO ( H B )≥ E HOMO ( E B ) (5a)
0.2 eV≤ E HOMO ( S B )− E HOMO ( H B )≤0.8 eV (5b).