Perovskites: Emergence of highly efficient third‐generation solar cells

For decades, human beings have been trying to plug into the sun to satisfy our energy requirements. Solar energy harvesting technology is, at present, in its third generation. Among the emerging photovoltaics, perovskite solar cells, which are fast advancing, have great future scope as solar energy harvesters. Rapid technological growth within the decade makes it the most potent among third-generation photovoltaics. Since its introduction in 2009, photoconversion efficiencies (PCE) of perovskite solar cells has hiked from 3.9% to 25.8% by 2021. Despite the swift increase in PCE, perovskite photovoltaics have to cross many hurdles to reach the stage of commercialization. Issues like low stability and lead toxicity are matters of great concern. The choice of material in each layer and the interfacial engineering to create matching between surfaces play a significant role in enhancing device performance. This review focuses on the materials and functions of four different layers of perovskite solar cells: light-absorbing, electron transport, hole transport, and counter electrodes. A brief discussion of perovskite-silicon tandem and 2D/3D multidimensional solar cells is also included in the review. The emergence of environment-friendly, economically feasible, and efficient solar cell materials turns out to be milestones in the path toward the commercialization of perovskite solar energy harvesters. Highlights This review discusses the emergence of perovskite solar cells, which are of great importance in the rapidly growing photovoltaic technology. An overview of materials, structure, and working of different perovskite solar cell layers- active layer, hole transport layer, electron transport layer, and counter electrode, is given in the review. The evolution of different solar cell materials is discussed, and their performance is compared qualitatively and quantitatively.