High current density in light-emitting transistors of organic single crystals.

We measured the external electroluminescence quantum efficiency (eta(ext)) in light-emitting field-effect transistors (LETs) made of organic single crystals and found that, in the ambipolar transport region, eta(ext) is not degraded up to several hundreds A/cm(2) current-density range, which is 2 orders of magnitude larger than that achieved in conventional organic light-emitting diodes. The present result indicates the single-crystal organic LET is a promising device structure that is free from various kinds of nonradiative losses such as exciton dissociation near electrodes and exciton annihilations.