Borax-Assisted Ball Milling Produces High-Yield Tin Selenide Quantum Dots for Efficient Perovskite Solar Cell Applications

SnSe quantum dots (QDs) exhibit exceptional photoelectric and thermoelectric properties, making them highly promising for a wide range of applications in both photoelectric and thermoelectric devices. However, the scalable production of high-quality SnSe QDs with high yield remains a significant challenge. In this study, we present a borax-assisted ball-milling and sonication-assisted solvent exfoliation method to prepare SnSe QDs with lateral sizes on the scale of 5 nm from SnSe single crystals. The resulting SnSe QDs feature pristine surfaces, high crystallinity, and an impressive yield of 43.3%. The thin film formed by these pristine SnSe QDs displays a broad band gap and strong photoluminescence. In addition, a SnSe QDs thin film is utilized as an electron transfer layer (ETL) in n-i-p perovskite solar cells (PSCs), achieving a photoelectric conversion efficiency (PCE) of 21.33%, approaching the PCE (22%) of SnO2-based PSCs and significantly higher than the PCE of 14.49% observed in PSCs without an ETL. Furthermore, when the SnSe QD thin film is modified by streptomycin sulfate, the PCE of the corresponding PSC increases to 23.20%. This method for preparing SnSe QDs not only facilitates large-scale production but also opens up new avenues for a comprehensive exploration of their performance potential and shows the prospect of SnSe QD application in optoelectronic devices.