Dihydrolevoglucosenone - An alternative green solvent employed synthesis and fabrication of lead free perovskite halide thin film for optoelectronic applications

Lead-based perovskite halides exhibit exceptional optical and structural properties, positioning them as promising materials for optoelectronic applications. However, the presence of toxic lead and concerns regarding stability pose significant challenges to their commercialization. While lead toxicity receives considerable attention, the toxicity associated with solvent usage remains a less explored aspect. In this study, we address these concerns by introducing dihydrolevoglucosenone, or Cyrene, as a non-toxic solvent alternative to conventional options like DMF and GBL. Additionally, we eliminate the use of carcinogenic antisolvents during the deposition of solution-processed Cs3Bi2X9 (X = I & Br) films. This green solvent approach not only mitigates environmental risks but also enhances energy efficiency, with synthesis and fabrication processes conducted at ambient atmosphere and low temperatures (<120 degrees C). Structural and optical characterizations confirm the efficacy of Cyrene, yielding homogeneous, highly crystalline, and superior quality Cs3Bi2I9 and Cs3Bi2Br9 films with high absorption coefficient. Our findings signify a significant advancement towards sustainable synthesis methods for lead-free perovskite halides, with potential implications for replacing toxic solvents and advancing environmentally friendly optoelectronic technologies.