Optoelectronic Techniques Boost the Investigation on Hysteresis and Ion Migration in Perovskite Photovoltaics

Perovskite solar cells (PSCs) have drawn much attention in the photovoltaic field. At present, the energy conversion efficiency has achieved 25.5%. However, the hysteresis effect in the characterization of PSCs seriously affects the accuracy of PSCs technology. Therefore, hysteresis effect has become the object of attention in order to improve PSCs. In this paper, various photoelectric characterization techniques are mentioned for the study of hysteresis phenomena. Photoelectric characterization methods, space charge limited current, electrochemical impedance spectroscopy, transient photocurrent/photovoltage are introduced. In the end, hysteresis is a shift in the representation of carrier dynamics due to ion migration. Hysteresis shows a characteristic of sweep speed dependence, indicating that ion migration is a slow and low frequency behavior. By increasing the bias voltage, ion migration can be more intense and the hysteresis will be more obvious.