Observation of anomalous excitonic emission in V-doped WS2 QDs synthesized by hydrothermal method and subsequent mechanical exfoliation

IF 3.3 3区物理与天体物理 Q2 OPTICS

Journal of Luminescence Pub Date : 2024-09-19 DOI:10.1016/j.jlumin.2024.120904

Prarbdh Bhatt, Ashok Kumar Mondal, Nilanjan Halder

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引用次数: 0

Abstract

This study focuses on synthesizing vanadium (V) doped 2H phase WS₂ via a facile hydrothermal method and subsequent liquid phase mechanical exfoliation of the material into QD-like nanostructures. An increment in dopant percentage from 1 % to 7 % red shifted the band gap of WS₂ from 4.15 eV to 3.78 eV. The nanostructures show electronic transition due to B, A, and defect-bound excitons and demonstrate modulation of excitonic behavior with V doping. Low V doping provides the WS₂ material with a reduced B/A excitonic peak intensity ratio because of the nonradiative pathways favoring the relaxation of high energy B excitons to A excitons. High V doping results in anomalous emission behavior marked by an increased B/A ratio, attributed to positive trion formation as a result of excess free hole concentration due to the p-type vanadium. The study suggests that V-doped WS₂ nanostructures hold potential for technological applications, particularly in spintronics and photonics, emphasizing the importance of engineering exciton dynamics in two-dimensional materials using p-type substitutional dopants.

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观察水热法合成并随后机械剥离的掺 V WS2 QD 的异常激子发射

本研究的重点是通过简便的水热法合成掺杂钒（V）的 2H 相 WS2，并随后通过液相机械剥离将该材料制成类似 QD 的纳米结构。掺杂百分比从 1% 增加到 7%，使 WS2 的带隙从 4.15 eV 变为 3.78 eV。这些纳米结构显示出 B、A 和缺陷结合激子导致的电子转变，并显示出激子行为随 V 掺杂的变化而变化。低 V 掺杂使 WS2 材料的 B/A 激子峰强度比降低，因为非辐射途径有利于高能量 B 激子向 A 激子的弛豫。高掺钒会导致 B/A 比增加的反常发射行为，这归因于 p 型钒产生的过量自由空穴浓度形成了正三离子。这项研究表明，掺杂钒的 WS2 纳米结构具有技术应用潜力，尤其是在自旋电子学和光子学领域，同时强调了利用 p 型替代掺杂剂在二维材料中设计激子动力学的重要性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Luminescence 物理-光学

CiteScore

6.70

自引率

13.90%

发文量

850

审稿时长

3.8 months

期刊介绍： The purpose of the Journal of Luminescence is to provide a means of communication between scientists in different disciplines who share a common interest in the electronic excited states of molecular, ionic and covalent systems, whether crystalline, amorphous, or liquid. We invite original papers and reviews on such subjects as: exciton and polariton dynamics, dynamics of localized excited states, energy and charge transport in ordered and disordered systems, radiative and non-radiative recombination, relaxation processes, vibronic interactions in electronic excited states, photochemistry in condensed systems, excited state resonance, double resonance, spin dynamics, selective excitation spectroscopy, hole burning, coherent processes in excited states, (e.g. coherent optical transients, photon echoes, transient gratings), multiphoton processes, optical bistability, photochromism, and new techniques for the study of excited states. This list is not intended to be exhaustive. Papers in the traditional areas of optical spectroscopy (absorption, MCD, luminescence, Raman scattering) are welcome. Papers on applications (phosphors, scintillators, electro- and cathodo-luminescence, radiography, bioimaging, solar energy, energy conversion, etc.) are also welcome if they present results of scientific, rather than only technological interest. However, papers containing purely theoretical results, not related to phenomena in the excited states, as well as papers using luminescence spectroscopy to perform routine analytical chemistry or biochemistry procedures, are outside the scope of the journal. Some exceptions will be possible at the discretion of the editors.