Understanding the efficiency enhancement of perovskite solar cells with NaGdF4: Er3+/Yb3+ nanorods

Abstract

Perovskite solar cells have drawn significant attention due to their excellent photovoltaic characteristics. Upconversion luminescence material modification is a good strategy to extend the device response to the near-infrared region, which can further increase device efficiency. By adding NaGdF 4 :Er 3+ /Yb 3+ nanorods into chlorobenzene as an additive in the antisolvent to modify the perovskite layer, we found that upconversion luminescence nanoparticles can effectively improve the perovskite solar cell performance. However, unexpectedly, the photocurrent contributed by the infrared part is lower. The efficiency increase of perovskite solar cells is contributed by defect passivation. Further research shows that nanoparticles can effectively fill the holes and gaps at the grain boundaries, eliminate surface defects of the perovskite, and modify the perovskite film, which reduces carrier recombination and effectively improves the device's performance. Finally, the power conversion efficiency of the champion device can reach 21.1%. This research demonstrates the function of upconversion luminescence nanoparticles in PSCs and provides a simple way to improve the device's efficiency. • The up-conversion luminescence NaGdF 4 :Er 3+ /Yb 3+ is introduced into the perovskite layer via anti-solvent chlorobenzene. • The champion device achieved an efficiency of 21.1% by passivating perovskite grain defects through NaGdF 4 nanocrystals. • The reason for the efficiency enhancement is the increase of carrier lifetime rather than spectrum broadening to infrared field.