Formation and characterization of preferred oriented perovskite thin films on single-crystalline substrates

Three single-crystalline (Al₂O₃, GaN/Al₂O₃ and InAs) substrates are used to assist the formation of crystallographically preferred oriented CH₃NH₃PbI₃ (MAPbI₃) thin films. The estimation of the lattice mismatch at the MAPbI₃/substrate interface and water-droplet contact angle experiments indicate that the formation of a preferred oriented MAPbI₃ thin film is induced by the single-crystalline substrate and is insensitive to the surface wettibility of the substrate. Moreover, the experimental results suggest that the lattice mismatch at the MAPbI₃/single-crystalline semiconductor interface can strongly influence the photovoltaic performance of tandem solar cells.