Red fluorescent siloles with aggregation-enhanced emission characteristics

A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence (EL) performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, (MesB)(2)DTTPS, and (MesB)(2)DSTPS, showed the typical aggregation-enhanced emission (AEE) feature, while furan-containing one, (MesB)(2)DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of (MesB)(2)DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m(-2), 4.3 cd A(-1), 2.9 lm W-1, and 1.8%, respectively.