Enhanced Performance of Perovskite Solar Cells via Low‐Temperature‐Processed Mesoporous SnO 2

Perovskite solar cells (PSCs) based on planar SnO 2 (p‐SnO 2 ) demonstrate excellent performance due to the superior properties of SnO 2 as electron transporting layer (ETL). However, at present mesoporous SnO 2 (m‐SnO 2 ) still lags behind p‐SnO 2 due to problems in the fabrication process of m‐SnO 2 . In this paper, a new strategy for preparing m‐SnO 2 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 SnO 2 nanocrystals. Second, the degree of porosity and roughness of the m‐SnO 2 layer can be well controlled, making it friendly to the following deposition process of PSCs. The performance of the PSCs based on the m‐SnO 2 ETL prepared from this strategy shows an obvious improvement which is mainly from the improvement in J sc and FF, suggesting a higher carrier collection efficiency for the m‐SnO 2 ETL. The relevant characterizations including PL, TRPL, EIS, and KPFM confirm that the m‐SnO 2 ETL possesses stronger electron extraction capability than the p‐SnO 2 ETL. Hence, the proposed strategy can manifest the advantages of m‐SnO 2 ETL meanwhile refrain its negative impacts, and thus promote the progress of the m‐SnO 2 ETL‐based PSCs.