Functional cellulose paper with high transparency, high haze, and UV-blocking for perovskite solar cells

Perovskite solar cells (PSCs) have become a promising solar energy utilization technology due to their high energy conversion efficiency and low preparation cost. However, the inherent instability under UV illumination limits their practical applications. In this work, we developed a new approach to fabricate functional cellulose paper (FTH paper) with high transparency, high haze, and UV-blocking, which can be used to extend the lifespan of PSCs. When the impregnation amounts of carboxymethyl cellulose and tannic acid were 16 wt% and 0.7 wt%, the light transmittance and UV-blocking performance reached 86.8% (at 600 nm) and 83.1% (at 320 nm), respectively, while maintaining a haze of 71.5%. After protonation and desalination treatment, the FTH paper exhibited good water resistance and mechanical properties (71.49 MPa, 2156 folding cycles). More importantly, FTH paper coating can significantly improve optical path length and the UV-stability (improved by 26% after 100 h) of PSCs. This study not only provides a simple and effective strategy to improve the properties of PSCs but also opens the way for high-value utilization of paper materials.