Key Laboratory of Preparation and Applications of Environmental Friendly Materials, Ministry of Education, College of Chemistry, Jilin Normal University, Changchun 130103, China.
Key Laboratory of Functional Materials Physics and Chemistry, Ministry of Education, College of Physics, Jilin Normal University, Changchun 130103, China.
Molecules. 2019 Feb 2;24(3):551. doi: 10.3390/molecules24030551.
In this work, we introduced an ordered metal-semiconductor molecular system and studied the resulting surface-enhanced Raman scattering (SERS) effect. Ag-FeS nanocaps with sputtered films of different thicknesses were obtained by changing the sputtering power of FeS while the sputtering power of Ag and the deposition time remained constant. When metallic Ag and the semiconductor FeS are cosputtered, the Ag film separates into Ag islands partially covered by FeS and strong coupling occurs among the Ag islands isolated by FeS, which contributes to the SERS phenomenon. We also investigated the SERS enhancement mechanism by decorating the nanocap arrays produced with different FeS sputtering powers with methylene blue (MB) probe molecules. As the FeS sputtering power increased, the SERS signal first increased and then decreased. The experimental results show that the SERS enhancement can mainly be attributed to the surface plasmon resonance (SPR) of the Ag nanoparticles. The coupling between FeS and Ag and the SPR displacement of Ag vary with different sputtering powers, resulting in changes in the intensity of the SERS spectra. These results demonstrate the high sensitivity of SERS substrates consisting of Ag-FeS nanocap arrays.
在这项工作中，我们引入了一个有序的金属-半导体分子体系，并研究了由此产生的表面增强拉曼散射（SERS）效应。通过改变 FeS 的溅射功率，同时保持 Ag 的溅射功率和沉积时间不变，获得了具有不同厚度溅射薄膜的 Ag-FeS 纳米胶囊。当金属 Ag 和半导体 FeS 共溅射时，Ag 薄膜会分离成部分被 FeS 覆盖的 Ag 岛，并且由 FeS 隔离的 Ag 岛之间会发生强烈耦合，这有助于 SERS 现象的产生。我们还通过用不同 FeS 溅射功率制备的纳米胶囊阵列来研究 SERS 增强机制，并用亚甲基蓝（MB）探针分子进行修饰。随着 FeS 溅射功率的增加，SERS 信号先增加后减小。实验结果表明，SERS 增强主要归因于 Ag 纳米粒子的表面等离子体共振（SPR）。FeS 和 Ag 之间的耦合以及 Ag 的 SPR 位移随不同的溅射功率而变化，导致 SERS 光谱强度的变化。这些结果表明，由 Ag-FeS 纳米胶囊阵列组成的 SERS 基底具有很高的灵敏度。
