Light illumination and temperature-induced current–voltage hysteresis in single-crystal perovskite photodiodes

Abstract

Recently, current–voltage (IV) hysteresis, which is more frequently observed in thin film perovskite solar cells, has been intensively studied due to the destruction of data accuracy in device measurement. Here, we investigated the effect of light illumination and temperature on IV hysteresis in single crystal CH₃NH₃PbI₃ based lateral diodes. In the dark condition, the IV hysteresis is normal and decreases as the scan rate increases, which is related to relatively fast scans in our experiments. Even more interesting is that the reverse voltage scan curve intersects the forward voltage scan curve at a voltage U_cr under light illumination, dividing the IV hysteresis loop into two parts: inverted hysteresis (IH) part (lower voltage region) and normal hysteresis (NH) part (the higher voltage region). As the light intensity increases, the IH part expands while the NH part shrinks continuously. Interestingly, a complete cross over of the hysteresis from normal to inverted occurs at sufficiently high light intensities in the end. Furthermore, when the ambient temperature increases from 243 K to 343 K, the IV hysteresis continues to increase at first reaching a maximum value and then begins to decrease. It can be concluded that these phenomena are attributed to the competition between two mechanisms of ion migration and charge carrier trapping to de-trapping.