Lead-Reduced Halide Perovskite Solar Cells with Photo-Assisted Kelvin Probe Force Microscopy

With the intensification of the global energy crisis, characterized by increasing demand and diminishing fossil fuel reserves, it has become imperative to explore sustainable and efficient energy-harvesting technologies. Perovskite solar cells (PSCs) have rapidly gained prominence as a promising photovoltaic device, boasting power conversion efficiencies (PCE) exceeding 26%. However, the widespread use of lead (Pb) in PSCs introduces environmental and health hazards that pose challenges to their broad commercialization. In this presentation, I will introduce the strategic research roadmap of our group in advancing perovskite solar cell technology. Our discussion will be divided into four key areas: (1) high-efficiency perovskite solar cells employing metal-doped TiO₂ as the electron transport layer (ETL); (2) the design of side-chain modulated, carbazole-based bifunctional hole-shuttle interlayers; (3) the development of lead-reduced perovskite solar cells; and (4) the exploration of lead-free Ag₃BiI₆ rudorffite solar cells. Predicting the quality of photovoltaic (PV) materials necessitates a thorough understanding of the material properties, manufacturing processes, and the long-term performance of solar cells or modules. To this end, we utilize various methods and techniques. Photoluminescence (PL) and time-resolved photoluminescence (TRPL) is utilized to determine charge carrier lifetimes, recombination mechanisms, and assess the impact of defects on material quality. Generally, higher-quality PV materials are indicated by lower recombination rates, which can lead to potentially higher efficiencies in solar cell applications. The photo-assisted Kelvin Probe Force Microscopy (photo-assisted KPFM), an adaptation of traditional KPFM that includes sample illumination during measurement, proves especially beneficial for PV materials. It allows for the investigation of surface electron accumulation under conditions that closely replicate the operational environment of the solar cells. Our research group is committed to spearheading innovative solutions in PSCs that prioritize both high efficiency and environmental stewardship.