Effect of the Number and Substitution Pattern of Carbazole Donors on the Singlet and Triplet State Energies in a Series of Carbazole-Oxadiazole Derivatives Exhibiting Thermally Activated Delayed Fluorescence
作者:Matthew W. Cooper、Xiaoqing Zhang、Yadong Zhang、Soon Ok Jeon、Hasup Lee、Sunghan Kim、Canek Fuentes-Hernandez、Stephen Barlow、Bernard Kippelen、Seth R. Marder
DOI:10.1021/acs.chemmater.8b02632
日期:2018.9.25
varying number of 9H-carbazole donors onto 2-(pentafluorophenyl)-5-phenyl-1,3,4-oxadiazole yields a series of donor–acceptor compounds with similar electrochemical band gaps, but dissimilar optical properties. Each substitution of a carbazole onto the 2- and 4-positions results in a 150–200 meV stabilization of the first singlet excited state, evident in the fluorescent emission. The first triplet excited
将不同数量的9 H-咔唑供体取代为2-(五氟苯基)-5-苯基-1,3,4-恶二唑会生成一系列具有相似的电化学带隙但光学性质不同的供体-受体化合物。咔唑在2位和4位上的每次取代都会导致第一个单重态激发态稳定在150–200 meV,这在荧光发射中很明显。第一三重态激发态对这些取代较不敏感,从而导致单态和三态态之间的能量分离减少,ΔE ST随咔唑含量的增加而增加。使用施主-受主化合物制得的OLED器件表现出最低的ΔE ST制备并显示出天蓝色发射,其外部量子效率在10 cd m -2时高达24.4%,在1000 cd m -2时高达9.2%。