Influence of Driving Current on Photometric Performances of a White Light OLED

In this paper, we demonstrate how driving current affects photometric performances of a white light organic light emitting diode (OLED) for general lighting purpose. Experiments reveal that a ripple current with 40% amplitude, 50-Hz-100-kHz frequency, and sinusoidal and triangle waveform has little influence on the test OLED. In the pulse-width modulation mode, both duty cycle and frequency of pulse current affect OLED's performance, and more particularly, their efficacy and correlated color temperature. Such influences become worse at high frequency and low duty cycle. The reason for this influence is a considerable difference between electron and hole mobility, and a time-dependent distribution of charge carrier within the structure leading to a movement of recombination zone therefrom.