Transient quantum yield evolution of organic light-emitting devices submitted to low-level excitation: A photon counting investigation

摘要

The continuously growing interest in organic light-emitting devices (OLEDs) requires exhaustive experimental investigations to validate the theoretical models. Here, we propose a solution to the problem of the measurement of quantum yield when devices are probed with low-level signals that minimize perturbations. Our approach is based on the wave form recovery methodology. Under pulsed excitation, our results reveal a considerable increase of the quantum yield throughout the excitation pulse. This enhancement persists for 10 ms. The procedure has the capability to reveal features of the transient behaviors and aging that are blurred when OLEDs are operated with normal driving electric field and current density. This approach may provide a complementary way to a thorough investigation of the electronic processes and aging mechanisms of OLEDs.