Defective States in Micro-Crystalline CsPbBr₃ and Their Role on Photoconductivity

Intrinsic defects in CsPbBr₃ microcrystalline films have been studied using thermally stimulated current (TSC) technique in a wide temperature range (100⁻400 K). Below room temperature, TSC emission is composed by a set of several energy levels, in the range 0.11⁻0.27 eV, suggesting a quasi-continuum distribution of states with almost constant density. Above room temperature, up to 400 K, the temperature range of interest for solar cells, both dark current and photocurrent, are mainly dominated by energy levels in the range 0.40⁻0.45 eV. Even if measured trap densities are high, in the range 10¹³⁻10¹⁶ cm^-3, the very small capture cross-sections, about 10^-26 m², agree with the high defect tolerance characterizing this material.