Enhancing the stability of planar perovskite solar cells by green and inexpensive cellulose acetate butyrate

Although the efficiency of organic-inorganic hybrid halide perovskite solar cells has been improved rapidly, the intrinsic instability of perovskite materials restricts their commercial application. Here, an eco-friendly and low-cost organic polymer, cellulose acetate butyrate (CAB), was introduced to the grain boundaries and surfaces of perovskite, resulting in a high-quality and low-defect perovskite film with a nearly tenfold improvement in carrier lifetime. More importantly, the CAB-treated perovskite films have a well-matched energy level with the charge transport layers, thus suppressing carrier nonradiative recombination and carrier accumulation. As a result, the optimized CAB-based device achieved a cham-pion efficiency of 21.5% compared to the control device (18.2%). Since the ester group in CAB bonds with Pb in perovskite, and the H and O in the hydroxyl group bond with the I and organic cations in perovskite, respectively, it will contribute to superior stability under heat, high humidity, and light soaking condi-tions. After aging under 35% humidity (relative humidity, RH) for 3300 h, the optimized device can still maintain more than 90% of the initial efficiency; it can also retain more than 90% of the initial efficiency after aging at 65 degrees C, 65% RH, or light (AM 1.5G) for 500 h. This simple optimization strategy for perovskite stability could facilitate the commercial application of perovskite solar cells.(c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

In this study, an eco-friendly and low-cost organic polymer, cellulose acetate butyrate (CAB), was introduced to improve the stability and efficiency of perovskite solar cells. The CAB-treated perovskite film exhibited a well-matched energy level and superior stability, resulting in a significant improvement in the efficiency of the solar cells and the ability to maintain high efficiency in high humidity and high-temperature conditions.