Self-passivated hybrid perovskite films for improved photovoltaic performance of solar cells

Defect passivation management of perovskite films is of great importance in improving the performance of perovskite solar cells. Various in situ or post-passivation strategies were adopted to modify the optoelectric properties of perovskite films. However, these modifications increased the fabrication complexity and cost of the devices. Here, we developed a facile self-passivation strategy to effectively decrease charge trap states and suppress the non-radiative recombination loss in perovskite films. By simply aging the precursor solution, we found that the fabricated perovskite films possess residual PbI 2 phase that could decrease trap density, enhance the radiative recombination intensity, and facilitate charge transfer and collection. Therefore, the solar cells with this self-passivated perovskite film generated an increased efficiency of 21.1% compared to that of 19.9% for the control devices from fresh precursor solution. Graphical abstract