Over 24% Efficient Poly(vinylidene fluoride) (PVDF)‐Coordinated Perovskite Solar Cells with a Photovoltage up to 1.22 V

Abstract Recently, organic–inorganic metal halide perovskite solar cells (PSCs) have achieved rapid improvement, however, the efficiencies are still behind the Shockley–Queisser theory mainly due to their high energy loss ( E LOSS ) in open‐circuit voltage ( V OC ). Due to the polycrystalline nature of the solution‐prepared perovskite films, defects at the grain boundaries as the non‐radiative recombination centers greatly affect the V OC and limit the device efficiency. Herein, poly(vinylidene fluoride) (PVDF) is introduced as polymer‐templates in the perovskite film, where the fluorine atoms in the PVDF network can form strong hydrogen‐bonds with organic cations and coordinate bonds with Pb 2+ . The strong interaction between PVDF and perovksite enables slow crystal growth and efficient defect passivation, which effectively reduce non‐radiation recombination and minimize E LOSS of V OC . PVDF‐based PSCs achieve a champion efficiency of 24.21% with a excellent voltage of 1.22 V, which is one of the highest V OC values reported for FAMAPb(I/Br) 3 ‐based PSCs. Furthermore, the strong hydrophobic fluorine atoms in PVDF endow the device with excellent humidity stability, the unencapsulated solar cell maintain the initial efficiency of >90% for 2500 h under air ambient of ≈50% humid and a consistently high V OC of 1.20 V.