Deuteration Improved Stable and Efficient Perovskite Solar Cells

Traditional solution-processed perovskites often suffer from defects-induced nonradiative recombination, which has severely hindered the improvement of device performance, especially the fill factor (<i>FF</i>). Herein, we have successfully applied a deuterated precursor as a facile additive not only to improve the perovskite multigrain size with high crystalline order, but also passivate the surface defects. Time of Flight Secondary Ion Mass Spectrometry shows that this deuteration has successfully induced an intermediate to the CsFAPbI₃ crystal and exhibiting an increase in grain size and in phase crystallinity. Suppressed iodide ion migration was observed in the deuterium additive-treated devices after aging tests, indicating improved structural stability of perovskite crystals. As a result, these translation into a high fill factor of 83.85% and a power conversion efficiency of 23.45% based on an inverted planar heterojunction device. Also, the devices operate for over 1,000 h at the maximum power point under simulated AM 1.5 illumination, possess a better light soaking stability.