Embossed transparent electrodes assembled by bubble templates for efficient flexible perovskite solar cells

Flexible perovskite solar cells are promising power source candidates in wearable and portable electronics. However, the performance of flexible perovskite solar cells still lags the values reported in rigid devices. This issue is mainly due to the lack of suitable electrodes which possess low sheet resistance, high optical transmittance, and smooth surface. Here, we proposed a flexible electrode based on solution-processed silver grids. With the patterned micro-bubbles as templates, high-resolution sliver grids electrodes were fabricated, which showed a sheet resistance of 7.9 Ω/sq and optical transmittance over 85% (including the substrate, from 375 nm to 900 nm). Besides, the embossed sliver grids can assist the growth of perovskite crystals and provide localized channels for charge carrier transport. The corresponding flexible perovskite solar cells based on these flexible sliver grids electrodes achieved a power conversion efficiency of 18.49% with remarkable flexibility, which enhanced about 20% compared to the control devices.