Ultrathin (thickness less than 10 μm) and ultralight flexible perovskite solar cells (FPSCs) have attracted extensive research enthusiasm as power sources for specific potential lightweight applications, such drones, blimps, weather balloons avionics. Currently, there is still a certain gap between the conversion efficiency (PCE) of ultrathin FPSCs common FPSCs. This study demonstrates on 3-μm-...