Asymmetric voltage waveform for enhanced exciton generation in alternative-current field-induced electroluminescence device

We propose an alternating current (AC) field operation scheme by using an asymmetric voltage waveform to improve the electroluminescence property of AC field-induced electroluminescence (AC-FIEL) devices. Hole injection and transport can be improved by carbon nanotubes (CNT) doping into the emission layer of an AC-FIEL structure operated by a single electrode for AC-responsive alternating carrier injections. However, under an AC operation, highly unbalanced charge transports are inevitably present in CNT-doped AC-FIEL devices due to faster carrier paths through CNTs. Compared with symmetric waveform, asymmetric waveform can be adjusted to allow longer relative duty time for faster carriers in which the luminance level of CNT-doped AC-FIEL devices can be improved by 1.4 times at the same device structure and operation frequency condition.