Organic electroluminescent device emitting light

An organic electroluminescent device comprising a light-emitting layer B comprising:

• (i) a host material HB, which has a lowermost excited singlet state energy level S1H, a lowermost excited triplet state energy level T1H, and a highest occupied molecular orbital HOMO(HB) having an energy EHOMO(HB);
• (ii) a first thermally activated delayed fluorescence (TADF) material EB, which has a lowermost excited singlet state energy level S1E, a lowermost excited triplet state energy level T1E, and a highest occupied molecular orbital HOMO(EB) having an energy EHOMO(EB);
• and
• (iii) an emitter material SB, which has a lowermost excited singlet state energy level S1S and a highest occupied molecular orbital HOMO(SB) having an energy EHOMO(SB);
• wherein the relations expressed by the following formulas (1) to (5) apply:
• S1H>S1E (1)
• S1H>S1S (2)
• S1E>S1S (3)
• EHOMO(EB)>EHOMO(SB) (4)
• EHOMO(EB)>EHOMO(HB) (5), and
• wherein the TADF material EB comprises a structure according to Formula I-NRCT
• wherein:
• o is 0 or 1;
• m=1−o;
• X1 is N or B;
• X2 is N or B;
• X3 is N or B;
• W is selected from the group consisting of Si(R35)2, C(R35)2, and BR3S;
• each of R1S, R2S, and R3S is independently from each other selected from the group consisting of:
• C1-C5-alkyl,
• which is optionally substituted with one or more substituents R6S;
• C6-C60-aryl,
• which is optionally substituted with one or more substituents R6S;
• and
• C3-C57-heteroaryl,
• which is optionally substituted with one or more substituents R6S;
• each of RI, RII, RIII, RIV, RV, RVI, RVII, RVIII, RIX, RX, and RXI is independently from each other selected from the group consisting of:
• hydrogen, deuterium, N(R5S)2, OR5S, Si(R5S)3, B(OR5S)2, OSO2R5S, CF3, CN, halogen, C1-C40-alkyl,
• which is optionally substituted with one or more substituents R5S, and
• wherein one or more non-adjacent CH2-groups are each optionally substituted by R5SC═CR5S, C≡C, Si(R5S)2, Ge(R5S)2, Sn(R5S)2, C═O, C═S, C═Se, C═NR5S, P(═O)(R5S), SO, SO2, NR5S, O, S, or CONR5S;
• C1-C40-alkoxy,
• which is optionally substituted with one or more substituents R5S, and
• wherein one or more non-adjacent CH2-groups are each optionally substituted by R5SC═CR5S, C≡C, Si(R5S)2, Ge(R5S)2, Sn(R5S)2, C═O, C═S, C═Se, C═NR5S P(═O)(R5S), SO, SO2, NR5S, O, S, or CONR5S;
• C1-C40-thioalkoxy,
• which is optionally substituted with one or more substituents R5S, and
• wherein one or more non-adjacent CH2-groups are each optionally substituted by R5SC═CR5S, C≡C, Si(R5S)2, Ge(R5S)2, Sn(R5S)2, C═O, C═S, C═Se, C═NR5S, P(═O)(R5S), SO, SO2, NR5S, O, S, or CONR5S;
• C2-C40-alkenyl,
• which is optionally substituted with one or more substituents R5S, and
• wherein one or more non-adjacent CH2-groups are each optionally substituted by R5SC═CR5S, C≡C, Si(R5S)2, Ge(R5S)2, Sn(R5S)2, C═O, C═S, C═Se, C═NR5S, P(═O)(R5S), SO, SO2, NR5S, O, S, or CONR5S;
• C2-C40-alkynyl,
• which is optionally substituted with one or more substituents R5S, and
• wherein one or more non-adjacent CH2-groups are each optionally substituted by R5SC═CR5S, C≡C, Si(R5S)2, Ge(R5S)2, Sn(R5S)2, C═O, C═S, C═Se, C═NR5S, P(═O)(R5S), SO, SO2, NR5S, O, S, or CONR5S;
• C6-C60-aryl,
• which is optionally substituted with one or more substituents R5S;
• and
• C3-C57-heteroaryl,
• which is optionally substituted with one or more substituents R5S;
• R5S is at each occurrence independently from each other 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):
• R6S is at each occurrence independently from each other 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);
• wherein two or more of the substituents selected from the group consisting of RI, RII, RIII, RIV, RV, RVI, RVII, RVIII, RIX, RX, and RXI 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 X1, X2, and X3 is B and at least one of X1, X2, and X3 is N.