Ultralight flexible perovskite solar cells

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 as drones, blimps, weather balloons and avionics. Currently, there is still a certain gap between the power conversion efficiency (PCE) of ultrathin FPSCs and common FPSCs. This study demonstrates ultrathin FPSCs on 3-μm-thick parylene-C substrates via a flip-over transferring process. The Zr, Ti and Ga-doped indium oxide (ITGZO) film is employed as the bottom transparent electrode of ultrathin inverted FPSCs with a remarkable PCE of 20.2%, which is comparable to that based on common FPSCs. Devices on glasses and parylene-F (i.e., parylene-VT4) substrates were also constructed to verify the advantages of parylene-C. Furthermore, an excellent power-per-weight of 30.3 W g−1 is achieved attributed to remarkable PCE and ultrathin-ultralight substrates, demonstrating the great promise of fabricating efficient, ultrathin and ultralight solar cells with parylene-C films.