High efficiency blue light emitting unipolar transistor incorporating multifunctional electrodes

The authors report on blue light emitting unipolar organic light emitting transistors (OLETs) with external quantum efficiency up to 0.2% by using multifunctional Mg/Au electrodes formed in combination with an efficient light emitting fluorene derivative. A mobility up to 6× 10-6 cm2 V-1 s-1 has been achieved, which is comparable to previous results from time of flight mobility measurements. An anomalous light emission behavior is observed in unipolar OLETs. The phenomenon is discussed in light of the effects of electron injection and outcoupling efficiency, respectively. Our results show that the multifunctional electrodes are useful for implementing highly efficient unipolar OLETs.