Manipulating SnO<sub>2</sub> Growth for Efficient Electron Transport in Perovskite Solar Cells
Zongyao Qian, Libao Chen, Jinpei Wang, Ling Wang, Yingdong Xia, Xueqin Ran, Ping Li, Qi Zhong, Lin Song, Peter Müller‐Buschbaum, Yonghua Chen, Hui Zhang
Abstract
Abstract Solution‐processed tin oxide (SnO 2 ) is ubiquitously used as the electron transport layer (ETL) in perovskite solar cells, while the main concerns related to the application of SnO 2 nanoparticles are the self‐aggregation potential and infeasible energy level adjustment, leading to inhomogeneous thin films and mismatched energy alignment with perovskite. Herein, a novel route is developed by adding a functional titanium diisopropoxide bis(acetylacetonate) (TiAcAc) molecule, comprising TiO 4 4– core, functional CO, and long alkene groups, into the SnO 2 nanoparticle solution, to optimize the electronic transfer property of SnO 2 for efficient perovskite solar cells. It is found that the TiO 4 4– can be used to tune the electronic property of the SnO 2 layer, and the long alkenes can act as a stabilizer to avoid the nanoparticle aggregation and electronic glue among the SnO 2 nanoparticles in the eventual nanoparticulate thin film, enhancing its homogeneity and conductivity. Furthermore, the residual CO groups on the ETL surface can strongly associate with the Pb 2+ and improve the interface intimacy between the ETL and perovskite. As a result, the efficiency of perovskite solar cells can be boosted from 18% to above 20% with significantly reduced hysteresis by employing SnO 2 ‐TiAcAc as electron transport layer, indicating a great potential for efficient perovskite solar cells.