Low-temperature electrodeposited crystalline SnO2 as an efficient electron transporting layer for conventional perovskite solar cells

Tin oxide (SnO2) has recently attracted significant research interest for its role functioning as an efficient electron-transporting layer (ETL) due to its higher charge mobility than the commonly used titanium oxide (TiO2) for realizing high-performance perovskite solar cells (PVSCs). However, it is still challenging to develop a facile, low-temperature solution-based (< 100 degrees C) processing method to synthesize crystalline SnO2 with desirable charge mobility, which can facilitate its widespread applications in flexible optoelectronic devices. In this work, we utilize an electrochemical deposition technique to prepare SnO2 films at a reduced temperature below 100 degrees C. The electrodeposition endows the SnO2 film with high crystallinity and conductivity in addition to high transparency across the visible spectrum. Efficient photoluminescence (PL) quenching is observed in the bi-layered SnO2/CH3NH3PbI3 film, manifesting its efficient electron extraction capability from perovskite. Consequently, a conventional n-i-p PVSC using this electrodeposited SnO2 ETL shows a high PCE of 13.88% with negligible hysteresis. This work demonstrates a low-temperature solution-based preparation route for making crystalline SnO2 and its potential for application in large-scale PVSC production.