Solvent engineering with ACN for the growth of high-quality CsPbBr3 single crystals†

It is of great importance to choose a suitable solvent for the growth of high-quality CsPbBr₃ single crystals. Here, by introducing acetonitrile (ACN) to the mixture of dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) solvents, the solubility curve of CsPbBr₃ exhibits a monotonic decrease in the temperature range of 20–80 °C, which can reduce the growth temperature to around 45 °C. Besides, the addition of ACN significantly increased the yield of single crystals to 38.71%. The quality of CsPbBr₃ single crystals grown in the DMSO/DMF/ACN precursor was improved, evidenced by a full width at half maxima (FWHM) of 0.035° in the X-Ray rocking curve of (100) and the absence of secondary phase inside the crystal from the infrared image. A μτ value of 2.57 × 10⁻⁴ cm² V⁻¹ from the corresponding devices can be achieved, comparable to that of crystals grown by the melt method. Our work here provides a promising solution recipe for the preparation of high-quality CsPbBr₃ single crystals.