• Spectroscopy and Spectral Analysis
  • Vol. 43, Issue 4, 1075 (2023)
SUN Zhi-ming1、*, LI Hui1, FENG Yi-bo1, GAO Yu-hang1, PEI Jia-huan1, CHANG Li1, LUO Yun-jing1, ZOU Ming-qiang2, and WANG Cong1
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
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    DOI: 10.3964/j.issn.1000-0593(2023)04-1075-08 Cite this Article
    SUN Zhi-ming, LI Hui, FENG Yi-bo, GAO Yu-hang, PEI Jia-huan, CHANG Li, LUO Yun-jing, ZOU Ming-qiang, WANG Cong. Surface Charge Regulation of Single Sites Improves the Sensitivity of Raman Detection[J]. Spectroscopy and Spectral Analysis, 2023, 43(4): 1075 Copy Citation Text show less

    Abstract

    As an important means of material modification, single site regulation has developed rapidly in catalysis, energy, environment and other fields. The Surface charge, electronic structure and atomic space configuration can be effectively controlled by adjusting single sites, thus improving the overall properties of materials. In the field of Raman detection, surface charge and other key factors are widely recognized and currently being studied. However, there is no systematic study on the effect of single sites on surface charge regulation or Raman sensitivity. In this paper, the surface charge regulation of single sites (including single molecule, single atom and ligand complex in single atom center) is proposed and its effect on Raman detection sensitivity is studied. Through the classic specific response: the 6-mercapto 5-triazoline [4,3-B] -S-tetraazine (MTT) is synthesized with 4-amino-3-hydrazo-5-mercapto-1,2,4-triazole (AHMT) and formaldehyde, resulting in a very low detection limit of 10-12 mol·L-1 for the charge regulated Ag material by single molecule AHMT. It is much lower than the 10-9 mol·L-1 without single AHMT regulation, realizing the detection of formaldehyde molecule ultra-low concentration. We also studied the effects of single tungsten oxide regulation on the detection ability of standard molecules and pesticide residues in nonspecific reactions. Among them, the detection limit of Rhodamine 6G could be decreased from 10-12 to 10-14 mol·L-1, and the detection limit of thiramcould also be decreased from 10-9 to 10-11 mol·L-1. Therefore, the universality of the method of unit point control of surface charge was proposed. In addition, through the test of Zeta potential, it was found that the Ag surface potential regulated by single sites had a great change, which was more conducive to the capture of detection molecules, which was also the reason for the increased sensitivity of Raman detection, and also explained the universality of single sites regulation in the mechanism. Many speculations and research have been made on the deep mechanism: On the one hand, there is a chemical enhancement (CM) process due to the charge transfer between the single sites and the substrate. At the same time, there is a significant Electromagnetic field enhancement (EM) on the surface of Ag. The two enhancement mechanisms and the coordination with single sites system are necessary to further study the new physical mechanism of different single sites through experiments and theories. On the other hand, single sites may act as a new vibration mode, which synergistically interacts with surface plasmon resonance (SPR) and resonance of the molecule to be measured in the substrate to make Raman scattering resonance stronger, thus improving the sensitivity of Raman detection. The experiments and conclusions in this paper confirm the feasibility and necessity of single sites regulation in Raman detection, which makes it possible to further study in this field.
    SUN Zhi-ming, LI Hui, FENG Yi-bo, GAO Yu-hang, PEI Jia-huan, CHANG Li, LUO Yun-jing, ZOU Ming-qiang, WANG Cong. Surface Charge Regulation of Single Sites Improves the Sensitivity of Raman Detection[J]. Spectroscopy and Spectral Analysis, 2023, 43(4): 1075
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