Light emitting transistor for lasers

Organic light emitting transistors (LEFETs) are an emerging class of optoelectronics device. They can simultaneously execute light-emission and standard logic functions (ON/OFF) of a transistor in single device architecture. The unique features of LEFETs such as high current density (>A/cm²), low optical losses (associated with quenching at electrodes) and easy integration of optical resonators in transistor channel suggest that an LEFET device architecture could be a realistic route to realise a direct injection lasing in organic semiconductor. Although the brightness of LEFETs has improved over the last decade, their EOE at high brightness (and current density) are still very much sub-optimal. To achieve lasing threshold, very high brightness (or current density) at high EOE is required. Here we present our recent progress in developing high performance LEFETs and discuss factors that currently influence their performance.