Unique gap-related SERS behaviors of p-aminothiophenol molecules absorbed on TiO2surface in periodic TiO2/Ni nanopillar arrays

Zhijun Wu; Chunfang Zheng; Qi Lin; Qun Fu; Huaping Zhao; Yong Lei

doi:10.1088/1361-6528/ad2a5a

Unique gap-related SERS behaviors of p-aminothiophenol molecules absorbed on TiO₂surface in periodic TiO₂/Ni nanopillar arrays

Nanotechnology. 2024 Mar 4;35(21). doi: 10.1088/1361-6528/ad2a5a.

Authors

Zhijun Wu¹, Chunfang Zheng¹, Qi Lin¹, Qun Fu¹, Huaping Zhao², Yong Lei²

Affiliations

¹ Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai, 200444, People's Republic of China.
² Fachgebiet Angewandte Nanophysik, Institut für Physik & IMN MacroNano, Technische Universität Ilmenau, D-98693 Ilmenau, Germany.

PMID: 38368630
DOI: 10.1088/1361-6528/ad2a5a

Abstract

We observed a unique interpillar gap-related surface-enhanced Raman scattering (SERS) behavior ofp-aminothiophenol (PATP) molecules from periodic TiO₂nanopillar arrays with three gap sizes of 191, 297 and 401 nm, which is completely different from that on Ag and Ni nanopillar arrays. Especially, the gap-size-dependent charge-transfer (CT) resonance enhancement from TiO₂/Ni has been indicated through comparisons of variation trend of SERS intensities with inter-pillar gap size between TiO₂/Ni and Ag/TiO₂/Ni as well as Ni nanoarrays, and been confirmed by spectra of ultraviolet-visible absorption and photoluminescence. Results demonstrate that the CT resonance enhancement is more susceptible to the change of the gap size compared with the surface plasmon resonance (SPR) enhancement in TiO₂/Ni nanoarrays. Hence, SPR and CT enhancement showing different variation trend and rate with the gap size that leads to a different relative contribution of CT resonance to the overall SERS enhancement as gap size changes, and consequently results in a unique gap-related SERS behavior for TiO₂/Ni nanoarrays. The present study is not only helpful for investigating SERS mechanism for semiconductors but also providing a method to design and optimize periodic metal/semiconductor SERS substrates in a controllable way.

Keywords: SERS; TiO2/Ni nanopillar arrays; charge transfer; dependence; gap-related; surface plasmon resonance.