Li Anran, Lin Jie, Huang Zhongning, Wang Xiaotian, Guo Lin
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China; Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China.
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China; Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China.
iScience. 2018 Dec 21;10:1-10. doi: 10.1016/j.isci.2018.11.017. Epub 2018 Nov 13.
Exploring highly surface-enhanced Raman scattering (SERS)-active semiconductors is urgently required for practical applications. Here, with the guidance of theoretical calculations, amorphous rhodium sulfide microbowls with high enhancement factor (1 × 10) and low limit of detection (10 M) for rhodamine 6G are successfully developed. This remarkable sensitivity is attributed to quasi-resonance Raman effect and multiple light scattering. The first-principles calculations show that the energy gap of 4-nitrobenzenethiol adsorbed on RhS is greatly decreased by shifting its lowest unoccupied molecular orbital (LUMO) energy level close to the LUMO of RhS, enabling quasi-resonance Raman effect by visible light. The finite-difference time-domain simulations demonstrate the efficient photon trapping ability enabled by multiple light scattering. The optimum wavelength of ∼633 nm for SERS is predicted in simulations and confirmed in experiments. Our results provide both a deep insight of the photo-driven charge transfer process and an important guidance for designing SERS-active semiconductors.
实际应用迫切需要探索具有高表面增强拉曼散射（SERS）活性的半导体。在此，在理论计算的指导下，成功开发出了对罗丹明6G具有高增强因子（1×10）和低检测限（10 M）的非晶态硫化铑微碗。这种显著的灵敏度归因于准共振拉曼效应和多重光散射。第一性原理计算表明，吸附在RhS上的4-硝基苯硫醇的能隙通过将其最低未占据分子轨道（LUMO）能级移近RhS的LUMO而大大降低，从而能够通过可见光实现准共振拉曼效应。时域有限差分模拟证明了多重光散射实现的高效光子捕获能力。模拟中预测了SERS的最佳波长约为633 nm，并在实验中得到了证实。我们的结果既深入洞察了光驱动电荷转移过程，又为设计SERS活性半导体提供了重要指导。
