Enhanced Performance of Perovskite Solar Cells via Low‐Temperature‐Processed Mesoporous SnO2

Perovskite solar cells (PSCs) based on planar SnO2 (p‐SnO2) demonstrate excellent performance due to the superior properties of SnO2 as electron transporting layer (ETL). However, at present mesoporous SnO2 (m‐SnO2) still lags behind p‐SnO2 due to problems in the fabrication process of m‐SnO2. In this paper, a new strategy for preparing m‐SnO2 ETL is introduced which owns two valuable features: First, it applies a low temperature process to make mesoporous structure, which favors preserving the pristine properties of the raw SnO2 nanocrystals. Second, the degree of porosity and roughness of the m‐SnO2 layer can be well controlled, making it friendly to the following deposition process of PSCs. The performance of the PSCs based on the m‐SnO2 ETL prepared from this strategy shows an obvious improvement which is mainly from the improvement in Jsc and FF, suggesting a higher carrier collection efficiency for the m‐SnO2 ETL. The relevant characterizations including PL, TRPL, EIS, and KPFM confirm that the m‐SnO2 ETL possesses stronger electron extraction capability than the p‐SnO2 ETL. Hence, the proposed strategy can manifest the advantages of m‐SnO2 ETL meanwhile refrain its negative impacts, and thus promote the progress of the m‐SnO2 ETL‐based PSCs. A new strategy for preparing mesoporous SnO2 (m‐SnO2) film as electron transporting layer (ETL) for high efficiency perovskite solar cells (PSCs) is proposed to address the difficulties in the development of the m‐SnO2‐based PSCs. Enhanced performance of PSCs is achieved via this strategy, and it can manifest the advantages of m‐SnO2 ETL meanwhile refrain its negative impacts.