Comparison of the sputtered TiO 2 anatase and rutile thin films as electron transporting layers in perovskite solar cells

Abstract

We examine comparatively the performance of sputtered TiO 2 rutile and anatase thin films as an electron transport layer (ETL) in MAPbI 3 ‐based perovskite solar cells. Both anatase and rutile TiO 2 ETLs are deposited (on fluorine‐doped tin oxide [FTO] substrates) by magnetron sputtering in the form of nanocrystalline thin films. We systematically investigate the role of crystallographic phase composition of TiO 2 ETLs on the photovoltaic performance of perovskite solar cells. The champion power conversion efficiencies (PCEs) of 18.4% and 17.7% under reverse scan mode are obtained for perovskite solar cells based on TiO 2 anatase and TiO 2 rutile ETL, respectively. The results show that the magnetron sputtering deposited ETLs differ from each other only in their phase composition while the overall performance of the devices is not greatly affected by the crystallographic phase of the TiO 2 ETLs. Our results point to an important fact that for a proper and reliable comparison between the performance of TiO 2 anatase and rutile ETLs, it is crucial to investigate films of similar morphology and structure that are synthesize under similar conditions.