Issue 17, 2025, Issue in Progress

Photo-induced-photo-catalytic SERS with silver-deposited TiO2 nanorods for ultrasensitive and sustainable detection of low Raman cross-section molecules

Abstract

Surface-enhanced Raman spectroscopy (SERS) offers significant advantages, including label-free, non-invasive analysis and ultrasensitivity down to the single-molecule level, making it widely applicable in analytical chemistry and biology. However, its effectiveness is limited when detecting molecules with inherently low Raman scattering cross-sections, restricting its broader applications. In this study, we apply the photo-induced-photo-catalytic SERS (PI-PC SERS) technique, utilizing an Ag-deposited TiO2 nanorod (Ag/TiO2 NR) substrate to overcome this limitation. The PI-PC SERS technique combines two optoelectronic effects: photo-induced enhanced Raman scattering (PIERS) and the photocatalytic activity of the metal/semiconductor substrate. PIERS amplifies Raman signals beyond normal SERS, while the photocatalytic effect facilitates the removal of residual analytes. The PI-PC SERS process follows three sequential irradiation steps: (i) pre-irradiation with 365 nm UV light to activate PIERS, (ii) laser excitation at 785 nm to capture the enhanced Raman signal, and (iii) post-irradiation with 365 nm UV light to trigger photocatalytic degradation. Two low Raman cross-section molecules, 4-nitrophenol (a widely used pesticide) and urea (an important biomarker), were selected to evaluate the performance of the PI-PC SERS technique on the Ag/TiO2 NR substrate. The results demonstrated that PI-PC SERS not only enhanced detection sensitivity tenfold compared to normal SERS but also enabled self-cleaning by efficiently removing residual analytes after measurement, ensuring substrate reusability. These findings pave the way for advancing SERS-based techniques for detecting low Raman cross-section molecules while broadening their potential applications in chemical and biological sensing fields.

Graphical abstract: Photo-induced-photo-catalytic SERS with silver-deposited TiO2 nanorods for ultrasensitive and sustainable detection of low Raman cross-section molecules

Article information

Article type
Paper
Submitted
20 Feb 2025
Accepted
17 Apr 2025
First published
24 Apr 2025
This article is Open Access
Creative Commons BY license

RSC Adv., 2025,15, 13172-13187

Photo-induced-photo-catalytic SERS with silver-deposited TiO2 nanorods for ultrasensitive and sustainable detection of low Raman cross-section molecules

Q. Mai, D. Thi Hanh Trang, N. Thi Loan, N. H. Tran Thi, O. Van Hoang, T. Ngoc Bach, N. Quang Hoa, A. Pham and A. Le, RSC Adv., 2025, 15, 13172 DOI: 10.1039/D5RA01238D

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