Highly Foldable Perovskite Solar Cells Using Embedded Polyimide/Silver Nanowires Conductive Substrates

Foldable solar cells, with the advantages of size compactness and shape transformation, are attractive power sources for wearable and portable devices. The challenge for realizing highly foldable solar cells is to exploit highly foldable conductive substrates to replace brittle indium tin oxide. In this work, highly foldable and smooth polyimide (PI)/silver nanowires (AgNWs) conductive substrates are constructed by embedding AgNWs into ultrathin PI films to improve the interface binding force. As a result, the embedded PI/AgNWs complex shows a neglectable change in resistance after folding for 1000 cycles. The perovskite solar cells (PSCs) on PI/AgNWs substrates exhibit power conversion efficiency (PCE) of 11.8%. More importantly, beneficial from the highly foldable PI/AgNWs conductive substrates, the PSCs maintain 73.5% and 55.2% of the initial PCE after +180° and −180° folding for 1000 cycles, respectively, which is the first report on the foldable AgNWs-based PSCs. In addition, the degradation mechanism of PSCs subjected to different folding conditions is tentatively exploited. This work paves the way toward realizing highly foldable PSCs for various practical applications.