Highly Visible-Transparent and Color-Neutral Perovskite Solar Cells for Self-Powered Smart Windows

Electrochromic smart windows can reduce the energy consumption of buildings by managing the light and heat transmission. However, they need external power to work, raising the installation cost and compromising the aesthetics of the buildings. Self-powered smart windows without external power sources have great potential in practical applications. Transparent solar cells can be integrated with smart windows and serve as their power sources. High optical transmittance, good color neutrality, and high power conversion efficiency (PCE) are required for the transparent solar cells to meet the optical and power requirements of self-powered smart windows. Herein, an efficient MAPbCl₃-based transparent perovskite solar cell (TPSC) using a solvent-assisted two-step approach is developed. The transparency and color-neutrality of the TPSCs are optimized through delicately selecting and pairing the charge transport layers and transparent electrodes. The TPSCs achieve a PCE up to 1.06% and average visible transmittance up to 72%. Self-powered smart windows powered by the TPSCs show fast and reversible modulation of visible light from 55% to 5% without external power input. This work demonstrates the prospect of deploying TPSCs in a self-powered smart window for energy saving and sustainable buildings.