Tantalum disulfide quantum dots: preparation, structure, and properties.

Tantalum disulfide (TaS) 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-TaS quantum dots (1 T-TaS QDs) by top-down method. Herein, we prepared the TaS 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 TaS QDs exhibited ultraviolet absorption at 283 nm. Furthermore, we found that dimension reduction of TaS 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 TaS QDs have unique and extraordinary optical properties. Moreover, the low-cost, facile method of producing high quality TaS QDs in this work is ideal for mass production to ensure commercial viability of devices based on this material. TaS 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 TaS has led to a transition from indirect to direct band gap that results in the unique and extraordinary optical properties (PL QY: 45.6%).