Akita Atsunobu, Fujishima Musashi, Tada Hiroaki
Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
Langmuir. 2021 Feb 9;37(5):1838-1842. doi: 10.1021/acs.langmuir.0c03184. Epub 2021 Jan 29.
An reduction technique consisting of chemisorption of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and subsequent reaction with HAuCl has been developed for depositing Au nanoparticles (NPs) uniformly in the depth direction of a mesoporous TiO nanocrystalline film (Au/TMCTS/mp-TiO). The TMCTS monolayer is further converted into silicon oxide by heating in the air (Au/SiO/mp-TiO). In the absorption spectra of Au/SiO/mp-TiO prepared at varying HAuCl concentrations (), the localized surface plasmon resonance (LSPR) band of Au NPs significantly broadens ≈ 1.22 mM at 546 nm to be split into two peaks around 500 and 700 nm at ≥ 2.43 mM, whereas such a phenomenon is not observed for the usual Au NP-loaded TiO particles. Three-dimensional-finite difference time domain simulations showed that the unique optical property of Au/SiO/mp-TiO stems from the effective LSPR coupling of very close Au NPs and partial fusions in the nanospaces of mp-TiO. Further, the optical hot spots in Au/TMCTS/mp-TiO as well as Au/SiO/mp-TiO generate an intense local electric field giving increase to a great enhancement of the absorption in the infrared spectrum of the TMCTS monolayer on mp-TiO.
一种由1,3,5,7-四甲基环四硅氧烷（TMCTS）化学吸附及随后与HAuCl反应组成的还原技术已被开发出来，用于在介孔TiO纳米晶膜（Au/TMCTS/mp-TiO）的深度方向上均匀沉积金纳米颗粒（NPs）。通过在空气中加热，TMCTS单分子层进一步转化为氧化硅（Au/SiO/mp-TiO）。在不同HAuCl浓度（）下制备的Au/SiO/mp-TiO的吸收光谱中，金纳米颗粒的局域表面等离子体共振（LSPR）带在546 nm处显著变宽（≈1.22 mM），在≥2.43 mM时分裂为500和700 nm左右的两个峰，而对于通常负载金纳米颗粒的TiO颗粒则未观察到这种现象。三维有限差分时域模拟表明，Au/SiO/mp-TiO独特的光学性质源于非常接近的金纳米颗粒的有效LSPR耦合以及mp-TiO纳米空间中的部分融合。此外，Au/TMCTS/mp-TiO以及Au/SiO/mp-TiO中的光学热点产生强烈的局部电场，使mp-TiO上TMCTS单分子层的红外光谱吸收大大增强。
