A Single‐Step Electrochemical Synthesis of Luminescent WS₂ Quantum Dots

Abstract

Transition-metal dichalcogenide quantum dots (TMDQDs) with few layers are in the forefront of recent research on tailored 2D layered materials owing to their unique band structure. Such quantum dots (QDs) draw wide interest as potential candidates for components in optoelectronic devices. Although a few attempts towards single step synthesis of MoS QDs have been demonstrated, limited methods are available for WS QDs. Herein, we demonstrate a one-step electrochemical synthesis of luminescent WS QDs from their bulk material. This is achieved by a synergistic effect of perchlorate intercalation in non-aqueous electrolyte and the applied electric field. The average size of the WS QDs is 3 ±1 nm (N=102) with few layers. The QDs show a higher photoluminescence (PL) quantum efficiency (5 %) and exhibit an excitation wavelength-dependent photoluminescence. This unprecedented electrochemical avenue offers a strategy to synthesize size tunable WS nanostructures, which have been systematically investigated by various characterization techniques such as transmission electron microscopy (TEM), photoluminescence and UV/Vis spectroscopies, and X-ray diffraction (XRD). Time-dependent TEM investigations revealed that time plays a vital role in this electrochemical transformation. This electrochemical transformation provides a facile method to obtain WS QDs from their bulk counterpart, which is expected to have a greater impact on the design and development of nanostructures derived from 2D materials.

Electrochemical Method To Prepare Graphene Quantum Dots and Graphene Oxide Quantum Dots

“…This methodology ensures an easy approach toward the synthesis of GQDs and GOQDs, which is quite similar to electrochemical preparation of tungsten disulfide quantum dots and molybdenum disulfide quantum dots. 28,29 The steps for preparing the GQDs and GOQDs are essentially the same. The GOQDs are obtained by varying the concentration of NaOH in the electrolyte.…”

Realization of Lasing Emission from One Step Fabricated WSe2 Quantum Dots

“…Nanoluminescent materials have always been the hotspot of scientific research [ 1 , 2 , 3 ]. Among these, pioneering work on layered materials has been done to explore the potential of layered materials in diverse applications [ 4 ]. Two-dimensional (2D) transition-metal dichalcogenides (TMDCs), especially, have attracted significant attention because of their unique properties [ 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…Two-dimensional (2D) transition-metal dichalcogenides (TMDCs), especially, have attracted significant attention because of their unique properties [ 5 , 6 , 7 , 8 , 9 , 10 ]. TMDCs quantum dots (QDs) have also been studied intensively as future optoelectronic materials owing to their dramatic properties [ 4 , 11 , 12 , 13 ] and widespread applications, such as fluorescent imaging, biomedical imaging, biological sensing [ 14 ], light emitting devices [ 15 ], photocatalytic, and hydrogen generation [ 16 ] et al [ 17 , 18 ]. TMDCs systems have been demonstrated to exhibit distinctive photoluminescence (PL) characteristics [ 19 , 20 , 21 , 22 ] because of their direct energy band gap.…”

Recent Progress in Chemiresistive Gas Sensing Technology Based on Molybdenum and Tungsten Chalcogenide Nanostructures

“…Valappil et al synthesized WS 2 quantum dots (≈3 ± 1 nm) from bulk via a single step electrochemical process in a nonaqueous electrolyte (propylene carbonate with 0.1 wt% LiClO 4 ) by applying a potential of +2.0 V versus Pt quasi reference electrode (QRE). 52…”