Paper published: Dual state emission of an organic semiconductor

A new paper was just published in Applied Physics Letters entitled ‘High efficiency,  dual emission from an organic semiconductor‘. The work describes the observation of highly efficient luminescence of both singlet and triplet states of a purely organic semiconductor, namely N,N’-bis(4-benzoyl-phenyl)-N,N’-diphenyl-benzidine, at room temperature. This unusual observation is the result of a very effective suppression of non-radiative modes within the triplet manifold of the molecule, enabling high efficiency phosphorescence. Together with efficient fluorescence, this molecule transforms in a dual state emitter, a phenomenon we term ‘biluminescence’. As neither singlet nor triplet states are a loss channel in the emitter molecule, the mixing between the two states through intersystem crossing (ISC) and back (reverse ISC) only dictates the relative intensities of fluorescence and phosphorescence. An biluminescence emitter may find future applications as ultra broadband emitters, exciton probes, various types of sensors, and spin independent energy transfer intermediates.