Well-organized SnO2 inverse opal monolayer as structured electron transport layer for high-efficiency perovskite solar cells

Abstract

In mesoporous perovskite solar cells (mp-PSCs), an electron transport layer (ETL) plays an important role in charge extraction and transportation, and also its structure largely affects the crystallization and optical property of perovskite films. At present, the performance of PSCs based mesoporous SnO2 (mp-SnO2) still lags behind that based planar SnO2 due to problems in the fabrication process of mp-SnO2. Herein, a well-organized monolayer SnO2 inverse opal (SIO) is prepared as the structured ETL for perovskite solar cells. The unique periodic SIO structure exhibits an obvious optical coupling phenomenon, which enhances the light absorption of the perovskite layer. Furthermore, the well-organized SIO structure with appropriate pore size triggers the confined crystallization of perovskite films and optimizes the interface of SnO2/perovskites, suppressing the interfacial electron–hole recombination. As a result, the power conversion efficiency of mp-PSCs fabricated by the monolayer SIO is boosted from 19.63% to 22.01%. This work provides a creative strategy for construction of high-efficiency mp-PSCs based on SnO2.