Sonochemical-assisted synthesis of CsPbBr3 perovskite quantum dots using vegetable oils†

Abstract

Cesium lead halide (CsPbX₃) perovskite quantum dots (PQDs) have attracted attention for use as absorber materials in photovoltaics as they show tuneable bandgap energy and high photoluminescence quantum yields together with the potential to demonstrate long-term stability and simple solution processability. Currently, the colloidal synthesis of PQDs relies to a large extent on the use of toxic and fossil derived solvents as the reaction medium. Alternative methods that partially or completely replace such solvents are anticipated as a step forward in meeting the sustainability criteria for the large-scale synthesis of PQDs. Herein, we report an eco-friendly sonochemical-assisted synthesis of CsPbBr₃ PQDs using commercial vegetable oil solvents as the reaction medium. The effect of different vegetable oils on the synthesis and properties of PQDs was investigated in detail. The as-prepared CsPbBr₃ colloids show similar photoluminescence (PL) spectra and crystalline structure to colloids obtained in mineral oil, which was used here for comparative purposes. Furthermore, a smaller amount of the optically inactive Cs₄PbBr₆ hexagonal crystalline phase was detected in the green synthesis compared to mineral oil-based synthesis. Finally, spin-coated thin films were produced, demonstrating the processability of the colloidal PQDs obtained via the green synthesis described here.