Synthesis and Functionalization of Transition Metal Dichalcogenides 2D Materials: Electrodes Design for Sensing Applications

过渡金属二硫属化合物（TMDCs）等电活性二维（2D）材料由于其独特的物理和电化学性质，在电子学、光电子学、电化学和传感器件等领域有着广泛的应用，引起了人们越来越多的关注。目前TMDC的合成策略主要依赖于自上而下的方法，如蚀刻和剥离。然而，基于自下而上的方法的化学气相沉积（CVD）生长过程有更好的机会产生具有更少缺陷，更均匀的化学成分，以及更好的短程和长程有序的TMDC纳米结构。自下而上的合成方法意味着通过将原子堆叠在彼此上而将纳米结构直接合成到期望的基底上，这产生晶面并导致纳米结构的合成。在自下而上的方法在文献中，有缺乏一个系统的理解的机制，二维材料的生长，不像一维材料的生长机制已经很好地理解。到目前为止，独立式2D材料的生长设计仍然是一种逐案实践。

Elecroactive two-dimensional (2D) materials including transition metal dichalcogenides (TMDCs) have attracted extensive and growing research interest owing to their exotic physical and electrochemical properties, which have enabled their applications in electronics, optoelectronics, electrochemical and sensing devices. Current synthesis strategies for TMDCs rely largely on top-down approaches such as etching and exfoliation. However, the bottom-up approach based chemical vapour deposition (CVD) growth processes has a better chance of producing TMDCs nanostructures with less defects, more homogenous chemical composition, and better short- and long-range ordering. A bottom-up synthesis method implies that the nanostructures are synthesized directly onto a desired substrate by stacking atoms onto each other, which gives rise to crystal planes and resulting in the synthesis of the nanostructures. Among bottom-up approaches in literature, there lacks a systematic understanding of the mechanisms of 2D materials growth, unlike one-dimensional materials whose growth mechanisms have been well understood. To date, the growth design of freestanding 2D materials remain a case-by-case practice.