Synthesis and characterisation of MoS₂ quantum dots by liquid nitrogen quenching

Abstract

Among transition metal dichalcogenides family, molybdenum disulphide (MoS 2 ) nanomaterial has a vital role in two-dimensional field due to its intrinsic optical and electronic properties. In this study, we report a new top-down approach for synthesising MoS 2 quantum dots (QDs). This strategy consists of liquid nitrogen (LN2) quenching of bulk MoS 2 material followed by two processes, probe sonication and ultra-centrifugation. This approach is simple, cost effective and eco-friendly. The structural, optical and morphological properties of obtained MoS 2 quantum dots were characterised. Photoluminescence spectra (PL) of the synthesised MoS 2 QDs show blue light emission when excited with ultraviolet radiation (365 nm). A significant observation in this study is that, the peak position of photoluminescence (PL) emission spectra is independent of excitation wavelength. In addition, a higher fluorescence quantum yield was obtained for the present MoS 2 QDs compared to MoS 2 QDs prepared by other methods.