Department of Chemical Engineering, Hanyang University , Ansan 426-791, Republic of Korea.
ACS Appl Mater Interfaces. 2017 Apr 12;9(14):12316-12323. doi: 10.1021/acsami.7b01644. Epub 2017 Mar 28.
Modulating the dimensions and phases of transition metal dichalcogenides is of great interest to enhance their intrinsic properties or to create new physicochemical properties. Herein, we report an effective approach to synthesize 2H-WS quantum dots (QDs) via the dimension and phase engineering of 1T-WS nanosheets. The solvothermal reaction of chemically exfoliated 1T-WS nanosheets in N-methyl-2-pyrrolidone (NMP) under an N atmosphere induced their chopping and phase transition at lower temperature to produce 2H-WS QDs with a high quantum yield (5.5 ± 0.3%). Interestingly, this chopping and phase transition process showed strong dependency on solvent; WS QDs were not produced in other solvents such as 1,4-dioxane and dimethyl sulfoxide. Mechanistic investigations suggested that NMP radicals played a crucial role in the effective production of 2H-WS QDs from 1T-WS nanosheets. WS QDs were successfully applied for the selective, sensitive, and rapid detection of dopamine in human serum (4 min, as low as 23.8 nM). The intense fluorescence of WS QDs was selectively quenched upon the addition of dopamine and Au ions due to fluorescence resonance energy transfer between WS QDs and the quickly formed Au nanoparticles. This new sensing principle enabled us to discriminate dopamine from dopamine-derivative neurotransmitters including epinephrine and norepinephrine, as well as other interference compounds.
调控过渡金属二卤族化合物的维度和相态对于增强其本征性能或创造新的物理化学性质具有重要意义。在此，我们通过 1T-WS 纳米片的维度和相工程，报道了一种合成 2H-WS 量子点（QD）的有效方法。在 N 气氛下，化学剥离的 1T-WS 纳米片在 N-甲基-2-吡咯烷酮（NMP）中的溶剂热反应，在较低温度下诱导其切割和相变，从而产生具有高量子产率（5.5±0.3%）的 2H-WS QD。有趣的是，这种切割和相变过程强烈依赖于溶剂；在其他溶剂如 1,4-二恶烷和二甲基亚砜中没有产生 WS QD。机理研究表明，NMP 自由基在 1T-WS 纳米片有效生成 2H-WS QD 中起关键作用。WS QD 成功地应用于人血清中多巴胺的选择性、灵敏和快速检测（4 分钟，检测限低至 23.8 nM）。由于 WS QD 与快速形成的金纳米粒子之间的荧光共振能量转移，多巴胺和 Au 离子的加入选择性地猝灭了 WS QD 的强烈荧光。这种新的传感原理使我们能够区分多巴胺与多巴胺衍生物神经递质，如肾上腺素和去甲肾上腺素，以及其他干扰化合物。
