摘要
A new pyrazino[2,3-g]quinoxaline carbazole derivative with branched alkyl peripheral chains PQC-12b with a donor–acceptor–donor nonplanar architecture is reported. PQC-12b exhibits high molar extinction coefficients, low bandgap, bright emission behavior in solution and solid-state, along with positive solvatochromism. PQC-12b is used in organic light-emitting diodes (OLEDs) either as sole emissive material or as a guest in different host materials. Amongst these different host–guest OLEDs, CBP-based device with the optimized concentration of PQC-12b shows maximum values for power efficacy (PE max ) of 14.1 lm W −1 , current efficacy of 26.8 cd A −1 , external quantum efficiency (EQE max ) of 8.0%, and lifetime of 5.1 h at an initial luminance of 5000 cd m −2 with a low power efficacy roll-off and roll-up character in current efficacy and EQE. A triplet exciton harvesting approach is employed by incorporating thermally activated delayed fluorescent emitter 4CzIPN to obtain a PE max of 33.4 lm W −1 , a CE max of 56.3 cd A −1 , an EQE max of 15.3%, and a maximum luminance (L max ) of 29 400 cd m −2 . Utility of the compound in solution-processable white OLED is explored and interestingly showed a PE max of 42.2 lm W −1 , a CE max of 40.3 cd A −1 , an EQE max of 12.0%, and L max of 24 667 cd m −2 .