Tantalum disulfide quantum dots: preparation, structure, and properties

Abstract: Tantalum disulfide (TaS₂) two-dimensional film material has attracted wide attention due to its unique optical and electrical properties. In this work, we report the preparation of 1 T-TaS₂ quantum dots (1 T-TaS₂ QDs) by top-down method. Herein, we prepared the TaS₂ QDs having a monodisperse grain size of around 3 nm by an effective ultrasonic liquid phase exfoliation method. Optical studies using UV-Vis, PL, and PLE techniques on the as-prepared TaS₂ QDs exhibited ultraviolet absorption at 283 nm. Furthermore, we found that dimension reduction of TaS₂ has led to a modification of the band gap, namely a transition from indirect to direct band gap, which is explained using first-principle calculations. By using quinine as reference, the fluorescence quantum yield is 45.6%. Therefore, our results suggest TaS₂ QDs have unique and extraordinary optical properties. Moreover, the low-cost, facile method of producing high quality TaS₂ QDs in this work is ideal for mass production to ensure commercial viability of devices based on this material. Graphical abstract: TaS₂ quantum dots having a monodisperse grain size of around 3 nm have been prepared by an ultrasonic liquid phase exfoliation method, it has been found that the dimension reduction of TaS₂ has led to a transition from indirect to direct band gap that results in the unique and extraordinary optical properties (PL QY: 45.6%).[Figure not available: see fulltext.].