An ultrathin and compact electron transport layer made from novel water-dispersed Fe3O4 nanoparticles to accomplish UV-stable perovskite solar cells

Abstract

UV induced decomposition of perovskite material is one of the main factors to severely destroy perovskite solar cells for instability. Here we report a UV stable perovskite solar cell with an Fe₂O₃ electron transport layer (ETL) made by spin-coating water dispersed Fe₃O₄ nanoparticles. Devices with Fe₂O₃ ETLs prepared from 10 nm Fe₃O₄ nanoparticles show nearly no decrease of photoelectric conversion efficiency (PCE) upon continuous exposure to very high UV light irradiation (300 W Xe lamp) for 10 hours in contrast to the TiO₂ ETL based samples with more than 30% reduction of PCE, and their PCE (14.33) is also much superior to those of devices with Fe₂O₃ ETLs made conventionally from FeCl₃ solution (7.7%). Through the study of Fe₂O₃ thin film prepared perovskite solar cells, it is found that compact, high transmittance, low leakage and low transmission impedance devices can be obtained by using an appropriate size of Fe₃O₄ nanoparticles. Our major findings are expected to provide a guide to design UV-protected compact electron transport layers for UV-stable perovskite solar cells.