Perovskite Light Emitting Diode Characteristics: The Effects of Electroluminescence Transient and Hysteresis

摘要

The reproducibility of results is one of the cornerstones of scientific research. However, in emerging technologies, the reported results often tend to be sensitive to the chosen measurement protocol. This can stem from measurement artifacts or from unknown complex underlying phenomena. Metal halide perovskites have emerged as an exciting material system for optoelectronic devices. The anomalous hysteresis in the current density-voltage (J-V) characteristics of perovskite solar cells has triggered wide discussions on how to report their power conversion efficiency to achieve consistency between different research groups. However, less attention is so far given to the anomalous effects that can affect the reporting of the characteristics of perovskite light emitting diodes (PeLEDs). Here, it is shown that even for PeLEDs with littleJ-Vhysteresis, the transient response and hysteresis of electroluminescence (EL), likely caused by ion migration, heat accumulation, and device degradation under electrical excitation, can lead to significantly different device characteristics depending on the measurement procedures for the same device. Therefore, a method based on pulsed excitation that allows for better reproducibility and interpretation of the measured device characteristics is proposed. Furthermore, suggestions are also provided on reporting PeLED characteristics, as input for further discussions in the scientific community.