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Abstract title Ionic migration in halide perovskites: Experimental evidence and correlation with optical properties
Author Khoram, Parisa, AMOLF, Amsterdam, Nederland (Presenting Author)
Abstract text

Hybrid perovskites have been used as the active layers in many optoelectronic devices such as solar cells, light emitting diodes, lasers, etc. due to their excellent properties. Despite the high performances of these devices, chemical toxicity and instability as well as unstable performance (for example current-voltage and maximum power point hysteresis) hinder their commercialization. The understanding of ionic transport as one of the main suggested mechanisms for the hysteresis and instability is an essential key toward engineering long-term halide perovskite device. In this work, we study the changes in photoluminescence (PL) of CH3NH3PbBr3 single crystals while electrical fields are applied systematically across the crystals, and observe increase (or decrease) of the PL according to the direction of electric field. Then we tracked the changes in halide distribution by means of synchrotron-based nanoprobe X-ray fluorescence (Nano-XRF). The ionic migration revealed from the elemental information by Nano-XRF explains the observed increase (or decrease) of the PL of the perovskite single crystals in halide rich (or poor) regions. The link between halide migration and changes in optical properties is reported in this study experimentally for the first time for the hybrid perovskite systems.