A new type of solid-state luminescent 2-phenylbenzo[g]furo[2,3-b]quinoxaline derivative: Synthesis, photophysical characterization and transporting properties

Organic semiconductors combining high mobility and efficient solid fluorescence are in high demand for developing organic light-emitting transistors and electrically driven organic lasers. But, achieving such dual functional molecules is extremely challenging. In this manuscript, we report 2-phenylbenzo[g]furo[2,3-b]quinoxaline derivatives (3a-3c) and develop a new synthesis method for the furo[2,3-b]quinoxaline core. It was found that 3a exhibited favorable aggregation induced emissive enhancement behavior and reasonable hole mobility. The absolute photoluminescence quantum yield of 3a is determined to be 22.1% in solid powders and can reach a maximum of 19.7% in 50% water in THF, twice that in CH₂Cl₂ solution (9.2%) and dispersed in PS film (9.3%). The single crystal and thin film organic field-effect transistor of 3a show a hole mobility of 2.58 × 10^-2 cm² V^-1 s^-1 and 5.7 × 10^-3 cm² V^-1 s^-1, respectively. Our results demonstrated that the 2-phenyl-benzo[g]furo[2,3-b]quinoxaline skeleton is a promising candidate for building multifunctional organic optoelectronics.