Highly Efficient, Dual State Emission From An Organic Semiconductor

We report highly efficient, simultaneous fluorescence and phosphorescence (74% yield) at room temperature from a single molecule ensemble of (BzP)PB [N,N'-bis(4-benzoyl-phenyl)-N,N'-diphenyl-benzidine] dispersed into a polymer host. The slow phosphorescence (208 ms lifetime) is very efficient (50%) at room temperature and only possible because the non-radiative rate for the triplet state is extremely low (2.4 x 10(0) s(-1)). The ability of an organic molecule to function as an efficient dual state emitter at room temperature is unusual and enables a wide range of applications including the use as broadband down-conversion emitters, optical sensors and attenuators, exciton probes, and spin-independent intermediates for Forster resonant energy transfer. (C) 2013 AIP Publishing LLC.