Influence of Ag Photodeposition Conditions over SERS Intensity of Ag/ZnO Microspheres for Nanomolar Detection of Methylene Blue

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 12; p. 3414
• Main Authors: Zamora-Peredo, Luis, García-Ramirez, Josué Ismael, García-Velasco, Amado Carlos, Hernández-Torres, Julián, García-González, Leandro, Bizarro, Monserrat, Báez-Rodríguez, Adriana
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16-12-2021; MDPI
• Subjects: Ag/ZnO microspheres; Deposition; Ethanol; Irradiation; Lasers; Methylene blue; Microspheres; Morphology; Nanoparticles; Optical properties; photodeposition; Precursors; Raman spectra; Raman spectroscopy; Rhodamine 6G; Scanning electron microscopy; SERS; Silver; Spectroscopy; Spectrum analysis; Substrates; Thickness; Transmission electron microscopy; Ultraviolet radiation; Vibration mode; X-ray diffraction; Zinc oxide; Zinc oxides; United States > US; Mexico; Japan; methylene blue; rhodamine 6G; SERS; Ag/ZnO microspheres; photodeposition
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11123414

Surface enhanced Raman spectroscopy (SERS) is considered a versatile and multifunctional technique with the ability to detect molecules of different species at very low molar concentration. In this work, hierarchical ZnO microspheres (ZnO MSs) and Ag/ZnO MSs were fabricated and decorated by hydrothermal and photodeposition methods, respectively. For Ag deposition, precursor molar concentration (1.9 and 9.8 mM) and UV irradiation time (5, 15, and 30 min) were evaluated by SEM, TEM, X-ray diffraction and Raman spectroscopy. X-ray diffraction showed a peak at 37.9° corresponding to the (111) plane of Ag, whose intensity increases as precursor concentration and UV irradiation time increases. SEM images confirmed the formation of ZnO MSs (from 2.5 to 4.5 µm) building by radially aligned two-dimensional ZnO nanosheets with thicknesses below 30 nm. The Raman spectra of Ag/ZnO MSs exhibited a vibration mode at 486 cm
which can be directly associated to Ag deposition on ZnO MSs surface. The performance of SERS substrate was evaluated using rhodamine 6G. The SERS substrate grown at 9.8 mM during 30 min showed the best SERS activity and the ability to detect methylene blue at 10
M.