Point defect-reduced colloidal SnO 2 electron transport layers for stable and almost hysteresis-free perovskite solar cells.

The commercialization of perovskite solar cells has been investigated, but the instability of their light-absorbing layers remains a problem. We demonstrate that the use of colloidal SnO 2 nanoparticles prevents perovskite light absorber decomposition, reduces the hysteresis index to 0.1%, and increases the power conversion efficiency to 19.12%.