Research Progress Of Compositional Controlling Strategy To Perovskite For High Performance Solar Cells

Over the past few years, the power conversion efficiency of perovskite solar cells have shown a tremendous progress from 3.8% in 2009 to 23.3% in 2018. Perovskites have exhibited excellent advantages in photovoltaic devices and other promising optoelectronic devices owing to their exceptional material properties, including direct and tunable bandgaps, strong light absorption, high electron/hole mobilities, long charge carrier lifetimes and diffusion lengths. The outstanding performance of perovskite solar cells is closely related with the deposition techniques and material composition of perovskite films. The preparation process of perovskite film is crucial for obtaining high efficiency devices, and it usually requires to fabricate a high coverage, compact and uniform perovskite layer. At present, the preparation technology of perovskite absorption layer mainly includes one-step processing, two-step processing, dual-source thermal evaporation processing, vapor-assisted solution processing and some scalable processing methods, and there are many reports and summaries about this work. However, perovskites still have some shortcomings such as insufficient light absorption range, poor long-term stability, the lead toxicity, which need to be overcome to realize higher power conversion efficiency and further product application. Compositional control engineering of perovskite materials becomes one of the effective ways to solve the above problems, but the summary of the research in this area is still lacking. In this review, we summarize the recent progress on the perovskite materials with different component systems, including organic-inorganic lead halide perovskite, all-inorganic lead halide perovskite, low-lead perovskite and lead-free perovskite. We also discuss some representative material compositions and the research on their corresponding preparation methods, the optimization of device structure and the effects on the device performance. Moreover, we compare and summarize the advantages and disadvantages of perovskite materials with different component systems. The purpose is to provide ideas on how to improve the efficiency and stability of perovskite solar cells through compositional controlling, and finally realize commercial application.