Cadmium doping for improving the efficiency and stability of carbon-based CsPbIBr2 all-inorganic perovskite solar cells

Abstract

The all-inorganic perovskite CsPbIBr₂ is a promising material in the photovoltaic (PV) field due to its acceptable optical bandgap and favorable air-stable phase stability. However, the conventional solution-processed poor-coverage thin films make it a challenging task to prepare high-performance solar cells. In this work, we introduce cadmium ions (Cd²⁺) into CsPbIBr₂ perovskite and investigate how this doping treatment would affect the PV performance of the carbon-based CsPbIBr₂ all-inorganic perovskite solar cells (FTO/SnO₂/CsPbIBr₂/carbon). We found that the crystallinity and morphology of CsPbIBr₂ thin films are significantly improved after Cd²⁺ doping, leading to improved light absorption and carrier transportation with reduced carrier recombination in perovskites. The optimized device achieved the highest efficiency of 6.79% in comparison with 4.36% for the device without Cd²⁺ doping, an increase of 56% in efficiency. Meanwhile, the optimized device with Cd²⁺ doping exhibited enhanced stability (76% of initial efficiency after 10 hours) in ambient atmosphere. Furthermore, the whole fabrication process of these devices is performed at low temperatures, not more than 160 °C. The present work provides a simple and economical strategy for the fabrication of low-temperature-processed CsPbIBr₂ solar cells and the improvement in their performance.