CsI Enhanced Buried Interface for Efficient and UV-Robust Perovskite Solar Cells

The buried interface between the perovskite and the electron transport layer (ETL) plays a vital role for the further improvement of power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). However, it is challenging to efficiently optimize this interface as it is buried in the bottom of the perovskite film. Herein, a buried interface strengthening strategy for constructing efficient and stable PSCs by using CsI-SnO2 complex as an ETL is reported. The CsI modification facilitates the growth of the perovskite film and effectively passivates the interfacial defects. Meanwhile, the gradient distribution of Cs+ contributes to a more suitable band alignment with the perovskite, and the incorporation of Cs+ into the perovskite at the bottom interface enhances the resistance against UV illumination. Eventually, a significantly improved PCE up to 23.3% and a much-enhanced UV stability of FAPbI(3)-based PSCs are achieved. This work highlights the importance of cesium-enhanced interfaces and provides an effective approach for the simultaneous realization of highly efficient and UV-stable perovskite solar cells.

Automated summary

By utilizing CsI-SnO2 complex as the buried interface for the electron transport layer, an effective strategy for enhancing the efficiency and stability of perovskite solar cells has been achieved. CsI modification facilitates perovskite film growth and defect passivation, while the gradient distribution of Cs+ contributes to suitable band alignment and enhanced resistance to UV exposure, resulting in significantly improved power conversion efficiency and UV stability for FAPbI(3)-based PSCs.