Commercial Carbon-Based all-Inorganic Perovskite Solar Cells with a High Efficiency of 13.81%: Interface Engineering and Photovoltaic Performance

The past few years have witnessed the rapid development of all-inorganic perovskite solar cells (PSCs). The interface of the electron transport layer (ETL)/perovskite is the vital charge separation site in all-inorganic PSCs. In this study, TiO2 nanorod arrays (NAs) were employed as electron transport layers in CsPbI2.25Br0.75 perovskite solar cells for enhancing the photovoltaic performance. Commercially available carbon was also used instead of the expensive hole transport materials and noble metals. The interface of TiO2/perovskite was further modified with cesium acetate (CsAc) to reduce the interface defect and the carrier recombination. The surface morphology, crystal structure, photoelectric property, and photovoltaic performance of the solar device were systematically investigated. More importantly, the device based on the CsAc-modified ETL/perovskite interface produced an optimization efficiency of 13.81%, which represents a record-breaking power conversion efficiency for carbon-based all-inorganic PSCs to date. This study emphasizes the critical importance of interface engineering of the ETL/perovskite and opens the door to the fabrication of carbon-based all-inorganic PSCs with high efficiency.