AgBi2I7 layers with controlled surface morphology for solar cells with improved charge collection

Abstract Silver iodobismuthates are semiconductor compounds potentially interesting for optoelectronics applications. In this work, a strategy is presented for the preparation by spin coating and at low temperature of well-crystallized, well-covering thin films with a AgBi2I7 global composition. The films are shown of high structural quality and the layer morphology has been controlled to produce either smooth or rough layers of similar thickness. We show that controlling the layer morphology and its interface with a hole transporting layer (Spiro-OMeTAD) plays an important role for the charge extraction and then the performances of devices. These films have been optimized and yielded perovskite -like solar cells with a maximum power conversion efficiency of 0.83%.