Light-emitting device, display panel, and display device

A light-emitting device, comprising:

• a first electrode and a second electrode that are stacked;
• and
• a light-emitting layer disposed between the first electrode and the second electrode;
• a material of the light-emitting layer including a thermally activated delayed fluorescence (TADF) material;
• wherein
• the TADF material includes a donor, an acceptor, and a linking group connected between the donor and the acceptor;
• the donor includes a donor base unit and a substituent connected to the donor base unit, and atoms in the donor base unit are located in a first plane;
• the acceptor includes an acceptor base unit and a substituent connected to the acceptor base unit, and atoms in the acceptor base unit are located in a second plane;
• the linking group includes a linking base unit and a substituent connected to the linking base unit, and atoms in the linking base unit are located in a third plane;
• wherein
• the donor is of one of structures shown in formula (I):
• the acceptor is of one of structures shown in formula (II):
• the linking group is any one of substituted or unsubstituted divalent aryl, substituted or unsubstituted divalent heteroaryl, substituted or unsubstituted divalent fused aryl, and substituted or unsubstituted divalent fused heteroaryl;
• Y is selected from the group consisting of substituted or unsubstituted divalent aryl, and substituted or unsubstituted divalent heteroaryl;
• R1 and R2 are each independently any one of alkyl, aryl, heteroaryl, fused aryl, and fused heteroaryl that are substituted or unsubstituted respectively;
• m and n are each a positive integer from 0 to 3;
• X1, X2 and X3 are each independently selected from any one of C(R) and N, and at least one thereof is N;
• R3, R4 and R are each independently any one of hydrogen, cyano, aryl, heteroaryl, fused aryl and fused heteroaryl;
• and
• dotted lines in the formula (I) and the formula (II) each represent a linking bond connected to the linking group.