Long-term stable silver nanowire transparent composite as bottom electrode for perovskite solar cells

As the most promising alternative to traditional indium tin oxide (ITO), silver nanowire (AgNW) composite transparent electrodes with improved stabilities compared with that of the pristine AgNWs networks have been demonstrated in various devices. However, a stable AgNW/polymer composite as the bottom electrode for perovskite solar cells has not yet been reported. Here, a long-term stable, smooth AgNW composite with an antioxidant-modified chitosan polymer was developed. The modified polymer can effectively protect pristine AgNWs from side reactions with perovskite, whereas it does not block the carrier drift through the interface of the insulating polymer. The as-prepared AgNW/polymer composite electrode exhibited a root mean square roughness below 10 nm at a scan size of 50 μm × 50 μm, and its original sheet resistance did not change obviously after aging at 85 °C for 40 days in air. As a result, the perovskite solar cell employing the composite as the bottom electrode yielded a power conversion efficiency of 7.9%, which corresponds to nearly 75% of that of the reference device with an ITO electrode.