Liao Chih-Kai, Phan Jasmine, Herrera Maura, Mahmoud Mahmoud A
Langmuir. 2019 Apr 9;35(14):4956-4965. doi: 10.1021/acs.langmuir.9b00205. Epub 2019 Mar 25.
Polyethylene glycol (PEG) assembled on the surface of two-dimensional tungsten disulfide (WS) into a limited number of nanoislands (NIs), nanoshells (NSs), and granular nanoparticulates (GNPs) depending on its chain length. NI assemblies showed a nonmeasurable shift of photoluminescence (PL) and the A and B absorption peaks of WS. This confirmed that the electronic doping by thiol is not effective. The PEG NS assembly displayed a smaller red shift of the PL and a slight decrease of the energy difference between the A and B absorption peaks of WS. However, increasing the dielectric function on the surface of WS has a small influence on their optical properties. The PEG NP assembly on WS exhibited a significant red shift of the PL spectrum and a large decrease of the energy difference between A and B absorption peaks. Deforming the WS sheet by the PEG NP assembly decreased the orbital coupling and lowered the electronic direct band gap significantly. Raman bands of WS are shifted to a higher frequency on improving its mechanical strength after the PEG assembly.
根据聚乙二醇（PEG）的链长，其在二维二硫化钨（WS）表面组装成数量有限的纳米岛（NIs）、纳米壳（NSs）和颗粒状纳米颗粒（GNPs）。纳米岛组装体显示出光致发光（PL）以及WS的A和B吸收峰不可测量的位移。这证实了硫醇的电子掺杂无效。PEG纳米壳组装体显示出较小的PL红移以及WS的A和B吸收峰之间能量差的轻微降低。然而，增加WS表面的介电函数对其光学性质影响较小。WS上的PEG纳米颗粒组装体表现出PL光谱的显著红移以及A和B吸收峰之间能量差的大幅降低。通过PEG纳米颗粒组装体使WS片变形降低了轨道耦合并显著降低了电子直接带隙。在PEG组装后，WS的拉曼带在提高其机械强度时向更高频率移动。
