Eco-Friendly All-Layer Green Solvent Efficient Perovskite Solar Cells

Perovskite solar cells (PSCs) have attracted significant attention for their utility in next-generation energy production technology due to their rapidly increasing power conversion efficiencies (PCEs), which have recently reached levels comparable to those of commercially successful Si solar cells. The simplicity and low cost of the perovskite solution processability have further heightened their commercial viability. However, the use of N,N-dimethylformamide (DMF)-a volatile toxic solvent-in this process is considered to be a major issue that not only poses significant challenges at the lab scale but also can potentially lead to serious human and environmental damage if introduced into production lines upon being commercialized. The present study aims to address the toxicity problem by classifying solvents into green and toxic categories and using only green solvents in the solution process to create high-efficiency PSCs. A specific challenge encountered in this process was the solubility issue of perovskite materials in green solvents, which led to the creation of perovskite films with inferior optical and electrical properties. This issue was resolved by ionizing perovskite materials with the addition of organic halide materials, ultimately enabling the fabrication of PSCs with PCEs reaching up to 20.6%. The green PCE metric of all-layer green solvent PSC is as high as 4.54, exceeding that of all the green solvent-based PSCs, thereby showing that this process achieves high efficiency while addressing relevant environmental and health impacts.