Synthesis of Bis(diarylphosphino)dithienosilole Derivatives as Novel Photo- and Electroluminescence Materials

Bis(diarylphosphino)dithienosiloles and their oxidized species were synthesized, and their optical properties were studied. They showed efficient photoluminescence (PL) in solutions as well as in the solid states, which was markedly affected by the phosphine oxidation states. The bis(diphenylphosphino) derivative exhibited reversible changes of the PL spectra in solutions upon interaction with Lewis acids. The electroluminescence properties were also examined, and a whitish-blue-green emission with a maximum luminance of ca. 130 cd/m2 was observed from a double-layered device having vapor-deposited films of bis(dinaphthylphosphino)dithienosilole dioxide and N,N′-diphenyl-N,N′-di-m-tolylbiphenyl-4,4′-diamine as the emitting and hole-transporting electron-blocking layers, respectively.