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

摘要

Recently, organic-inorganic metal halide perovskite solar cells (PSCs) haveachieved rapid improvement, however, the efficiencies are still behind theShockley-Queisser theory mainly due to their high energy loss (ELOSS) inopen-circuit voltage (V_(OC)). Due to the polycrystalline nature of the solutionpreparedperovskite films, defects at the grain boundaries as the nonradiativerecombination centers greatly affect the V_(OC) and limit the deviceefficiency. Herein, poly(vinylidene fluoride) (PVDF) is introduced as polymertemplatesin the perovskite film, where the fluorine atoms in the PVDFnetwork can form strong hydrogen-bonds with organic cations and coordinatebonds with Pb~(2+). The strong interaction between PVDF and perovksiteenables slow crystal growth and efficient defect passivation, which effectivelyreduce non-radiation recombination and minimize ELOSS of V_(OC). PVDF-basedPSCs achieve a champion efficiency of 24.21 with a excellent voltage of1.22 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 PVDFendow the device with excellent humidity stability, the unencapsulated solarcell 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.