Impact of Environmental Stresses Onto Transport Properties of Hybrid Perovskite Investigated by Steady State Photocarrier Grating and Steady State Photocurrent Techniques

In this study, the transport properties of high quality double and triple cation perovskite are explored under different environmental stresses by Steady State Photocurrent (SSPC) and Steady State Photocarrier Grating (SSPG) measurements. SSPG allows a direct measurement of the ambipolar diffusion length that is significantly higher for the cesium containing perovskite (1.4 micron compared to 0.57 micron for a double cation compound). This positive effect is shown to be reversibly annihilated as the samples are put under vacuum, and to be accelerated with the increase of the temperature. The degradation of the material properties appears together with the activation of a defect trap level and a rise of the doping level in the material. This behavior is discussed considering the interaction between the iodine vacancies contained in the perovskite and oxygen which is known to lead to trap passivation.