Highly efficient, dual state emission from an organic semiconductor

TL;DR

This paper demonstrates a single organic molecule ensemble that exhibits highly efficient dual fluorescence and phosphorescence at room temperature, enabling new applications in photonics and sensing.

Contribution

It introduces a novel organic molecule system capable of simultaneous efficient fluorescence and phosphorescence at room temperature, which is uncommon and opens new application avenues.

Findings

74% combined fluorescence and phosphorescence yield

Phosphorescence lifetime of 208 ms at room temperature

High triplet state efficiency due to low non-radiative rate

Abstract

We report highly efficient, simultaneous fluorescence and phosphorescence (74% yield) at room temperature from a single molecule ensemble of (BzP)PB 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. The ability of an organic molecule to function as an efficient dual state emitter at room temperature is unusual and opens new fields of applications including the use as broadband down-conversion emitters, optical sensors and attenuators, exciton probes, and spin-independent intermediates for F\"orster resonant energy transfer.