Bifunctional Passivation for Efficient and Stable Low-Temperature Processed All-Inorganic CsPbIBr2 Perovskite Solar Cells

Carbon-based all-inorganic CsPbIBr2 perovskite solar cells (PSCs) have attracted a lot of attention due to their simple fabrication process and good thermal stability. But the efficiency of devices is lower due to the poor quality of the solution-processed CsPbIBr2 film. A high-quality CsPbIBr2 film with large grain size, good crystallinity and reduced trap-state density is necessary for efficient PSCs. In this work, fluorine-containing trifluoroethyl methacrylate (TFEMA) is employed to improve the microstructure and photoelectrical properties of the low-temperature processed CsPbIBr2 film. Our all-inorganic PSCs consist of the FTO/TiO2/CsPbIBr2/carbon simple structure. The power conversion efficiency (PCE) of the modified PSCs using TFEMA (TFEMA-PSCs, 8.54%) is much higher than 31.8% of the Reference-PSCs (6.48%) and an open-circuit voltage (V-oc) of 1.305 V was achieved. The reasons for the improved performance have been systematically investigated. The characterizations show that the enhanced PCE in the TFEMA-PSCs can be ascribed to the optimized microstructure, decreased carrier recombination, reduced trap-state density and promoted charge transfer. This work provides an effective and facile strategy to prepare high-quality CsPbIBr2 films by low-temperature process.

Automated summary

This study focuses on improving the performance of CsPbIBr2 perovskite solar cells by using TFEMA, which results in enhanced efficiency due to optimized microstructure, reduced carrier recombination, lower trap-state density, and promoted charge transfer.