| abstract |
The present invention belongs to the technical field of OLED and provides a compound used as a host material, having the structure of formula (I); wherein X is selected from C, O, S, Se, Si or Te atoms; a and b represent electron donors, respectively The number of body D and electron acceptor A is selected from 1, 2 or 3, c and d are respectively selected from 0, 1 or 2; L 1 , L 2 and electron donor D are independently selected from alkyl, cyclic Alkyl, heterocyclyl, aryl, heteroaryl, fused aryl or fused heteroaryl; electron acceptor A is selected from nitrogen-containing heterocycles, cyano-containing, phosphorus-containing oxygen-containing substituents or triarylborons Substituents. The D-(π)-σ-(π)-A structure in the compound of the present invention has bipolarity, and the σ bond can effectively interrupt the intramolecular charge transfer between the electron donor D and the electron acceptor A, and make the excited state It is limited to the local excited state within the fragment of D or A, so that the compound has a small excited state dipole moment, when it is used as the host material of the light-emitting layer, it can effectively reduce the efficiency roll-off of the blue light material, improve the luminous brightness and Luminous efficiency. |