Emerging Roles of Inorganic and Copper Chalcogenide-Based Hole Transport Materials in Perovskite Solar Cells

In a decade ~7 times, enhanced efficiency was achieved for perovskite solar cells (PSCs) 3.5%–27%. The charge extraction by the selective contacts controls the efficiency. By its performance, the hole transport materials (HTMs) for PSC have attracted worldwide researchers. Organic HTMs have been studied and employed magnificently, but poor stability against humidity and high-cost organic HTMs remained a significant challenge. Consequently, alternate inorganic HTMs are being studied. Recently, chalcogenide-based HTMs are showing features such as tunable bandgap and appropriate band-edge position, high hole conductivity, mobility, and low production cost. This assessment presents advancement in the studies of inorganic HTM material based on chalcogenide for PSCs. The focus is on the effects of embodying chalcogenide as HTM in PSC and chances for further enhancement in garnering technologies. The optoelectronic features are highlighted in this review, including band structure, bandgap tuning, and hole mobility. The PSC community has been on the search for inorganic HTMs that might lead to a suitable approach.