Transient electroluminescence in a para-hexaphenyl based multilayer device

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