Phosphole-based pi-conjugated electroluminescent materials for OLEDs

Novel mixed phosphole-fluorene pi-conjugated systems have been prepared using the Fagan-Nugent route. Their optical (UV-visible absorption, fluorescence spectra) and electrochemical properties have been systematically evaluated. The variation of the substitution pattern of phosphole derivatives and chemical modification of their P atoms afford thermally stable derivatives which are photoluminescent. The use of these derivatives as emitters in OLEDs strongly depends on the substituent linked on the P-atom. The gold complexes are not stable electroluminescent materials since they decompose rapidly when the devices are operating. In contrast, the thiooxophospholes are stable electroluminescent materials, and the OLEDs incorporating these derivatives as emitters display very high performances.