Department of Chemistry, Yonsei University , Seoul 120-749, Korea.
J Am Chem Soc. 2014 Oct 22;136(42):14670-3. doi: 10.1021/ja5079943. Epub 2014 Oct 14.
A solution-phase synthetic protocol to form two-dimensional (2D) single-layer transition-metal chalcogenides (TMCs) has long been sought; however, such efforts have been plagued with the spontaneous formation of multilayer sheets. In this study, we discovered a solution-phase synthetic protocol, called "diluted chalcogen continuous influx (DCCI)", where controlling the chalcogen source influx (e.g., H2S) during its reaction with the transition-metal halide precursor is the critical parameter for the formation of single-layer sheets as examined for the cases of group IV TMCs. The continuous influx of dilute H2S throughout the entire growth period is necessary for large sheet formation through the exclusive a- and b-axial growth processes. By contrast, the burst influx of highly concentrated H2S in the early stages of the growth process forms multilayer TMC nanodiscs. Our DCCI protocol is a new synthetic concept for single-layer TMCs and, in principle, can be operative for wide range of TMC nanosheets.
一直以来，人们都在寻求一种形成二维（2D）单层过渡金属硫属化物（TMC）的溶液相合成方案；然而，这些努力一直受到多层片自发形成的困扰。在这项研究中，我们发现了一种溶液相合成方案，称为“稀释硫属物连续流入（DCCI）”，其中控制硫属物源（例如 H2S）在与过渡金属卤化物前体反应期间的流入是形成单层片的关键参数，这在检查 IV 族 TMC 的情况下得到了证实。在整个生长期间连续不断地流入稀 H2S 是通过专有的 a-和 b-轴向生长过程形成大片的必要条件。相比之下，在生长过程的早期阶段，高浓度 H2S 的爆发式流入会形成多层 TMC 纳米盘。我们的 DCCI 方案是一种用于单层 TMC 的新合成概念，原则上可适用于广泛的 TMC 纳米片。
