TY - JOUR AU - Le, Thi Thuy Huong AU - Truong, Dinh Hieu AU - Nguyen, Thi Le Anh AU - Pham Minh Quan, AU - Ngo, Thi Chinh AU - Duy Quang, Dao PY - 2022/03/23 Y2 - 2024/03/29 TI - SERS chemical enhancement of 2,4,5-trichlorophenoxyacetic acid absorbed on Au20, its Au-Ag and Au-Cu bimetallic clusters: a DFT study JF - Vietnam Journal of Science and Technology JA - Vietnam J. Sci. Technol. VL - 60 IS - 4 SE - Materials DO - 10.15625/2525-2518/16090 UR - https://vjs.ac.vn/index.php/jst/article/view/16090 SP - 641-651 AB - <p>The surface-enhanced Raman scattering (SERS) phenomenon of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) adsorbed on Au<sub>20</sub> pyramidal cluster is studied by Density Functional Theory. All possible adsorption configurations between the adsorbate and the Au<sub>20</sub> clusters are evaluated and the vibrational assignments of normal Raman and SERS spectra are analyzed. The result shows that the most stable adsorption configuration of the adsorbate on Au<sub>20</sub> cluster is formed by the interaction of O13 (-COOH group) and Au atom. The SERS activities of 2,4,5-T adsorbed on 1:1 Au-Ag and Au-Cu bimetallic clusters are also investigated. For bimetallic clusters, the substitution of 1, 4 or 10 Au atoms by Ag/Cu is performed by replacing the respective number of Ag/Cu atoms in 1, 2 and 3 parallel layers of the Au<sub>20</sub> cluster. While the Raman scattering activity of the Au<sub>10</sub>Ag<sub>10</sub> cluster is comparable to that of the Au<sub>20</sub> cluster, it is remarkably higher than the Au<sub>10</sub>Cu<sub>10 </sub>cluster. This observation is explained by the molecule-to-cluster charge transfer process. The obtained results are hoped to contribute to better design of SERS-based analytical sensors for mobile and on-site applications.</p> ER -