Transient electroluminescence in a para-hexaphenyl based multilayer device

An organic blue light emitting device (OLED) is investigated in terms of tr ansient electroluminescence (EL) and current characteristic. The driving vo ltage pulse mode is varied with respect to amplitude and pulse duration cov ering the range of 1 ms to 250 ms. The OLED performance is studied with res pect to response times, EL output and current densities. It is further demo nstrated that reverse biasing the device prior to the driving voltage pulse increases the external quantum yield by up to 25% by virtue of depleting s pace charge carriers and charge filled trap sites.