Kazemi Seyedeh Alieh, Imani Yengejeh Sadegh, Ogunkunle Samuel Akinlolu, Zhang Lei, Wen William, Wee-Chung Liew Alan, Wang Yun
Centre for Catalysis and Clean Energy, School of Environment and Science, Griffith University Gold Coast Campus QLD 4222 Australia
School of Information and Communication Technology, Griffith University Gold Coast Queensland 4215 Australia.
RSC Adv. 2023 Feb 24;13(10):6498-6506. doi: 10.1039/d3ra00205e. eCollection 2023 Feb 21.
Monolayers of transition metal dichalcogenides (TMD) exhibit excellent mechanical and electrical characteristics. Previous studies have shown that vacancies are frequently created during the synthesis, which can alter the physicochemical characteristics of TMDs. Even though the properties of pristine TMD structures are well studied, the effects of vacancies on the electrical and mechanical properties have received far less attention. In this paper, we applied first-principles density functional theory (DFT) to comparatively investigate the properties of defective TMD monolayers including molybdenum disulfide (MoS), molybdenum diselenide (MoSe), tungsten disulfide (WS), and tungsten diselenide (WSe). The impacts of six types of anion or metal complex vacancies were studied. According to our findings, the electronic and mechanical properties are slightly impacted by anion vacancy defects. In contrast, vacancies in metal complexes considerably affect their electronic and mechanical properties. Additionally, the mechanical properties of TMDs are significantly influenced by both their structural phases and anions. Specifically, defective diselenides become more mechanically unstable due to the comparatively poor bonding strength between Se and metal based on the analysis of the crystal orbital Hamilton population (COHP). The outcomes of this study may provide the theoretical knowledge base to boost more applications of the TMD systems through defect engineering.
过渡金属二硫属化物（TMD）单层具有优异的机械和电学特性。先前的研究表明，在合成过程中经常会产生空位，这会改变TMD的物理化学特性。尽管对原始TMD结构的性质进行了充分研究，但空位对电学和力学性能的影响却很少受到关注。在本文中，我们应用第一性原理密度泛函理论（DFT）来比较研究包括二硫化钼（MoS）、二硒化钼（MoSe）、二硫化钨（WS）和二硒化钨（WSe）在内的有缺陷TMD单层的性质。研究了六种类型的阴离子或金属络合物空位的影响。根据我们的研究结果，阴离子空位缺陷对电子和力学性能的影响较小。相比之下，金属络合物中的空位会显著影响其电子和力学性能。此外，TMD的力学性能受到其结构相和阴离子的显著影响。具体而言，基于晶体轨道哈密顿布居（COHP）分析，由于Se与金属之间的键合强度相对较差，有缺陷的二硒化物在力学上变得更加不稳定。本研究结果可为通过缺陷工程促进TMD系统的更多应用提供理论知识库。
