Mixed valence Ce-doped TiO2 with multiple energy levels and efficient charge transfer for boosted SERS performance

Jia Li; Huizhu Zhang; Dongxue Yu; Weie Wang; Wei Song; Libin Yang; Xin Jiang; Bing Zhao

doi:10.1016/j.saa.2022.121643

Mixed valence Ce-doped TiO₂ with multiple energy levels and efficient charge transfer for boosted SERS performance

Spectrochim Acta A Mol Biomol Spectrosc. 2022 Nov 15:281:121643. doi: 10.1016/j.saa.2022.121643. Epub 2022 Jul 18.

Authors

Jia Li¹, Huizhu Zhang², Dongxue Yu², Weie Wang², Wei Song³, Libin Yang⁴, Xin Jiang⁵, Bing Zhao⁶

Affiliations

¹ College of Materials Science and Engineering, College of Pharmacy, Jiamusi University, Jiamusi 154007, People's Republic of China; Key Laboratory of Preparation and Applications of Environmental Friendly Materials (Jilin Normal University), Ministry of Education, Changchun 130103, People's Republic of China.
² College of Materials Science and Engineering, College of Pharmacy, Jiamusi University, Jiamusi 154007, People's Republic of China.
³ State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, People's Republic of China.
⁴ College of Materials Science and Engineering, College of Pharmacy, Jiamusi University, Jiamusi 154007, People's Republic of China. Electronic address: yanglibin@jmsu.edu.cn.
⁵ College of Materials Science and Engineering, College of Pharmacy, Jiamusi University, Jiamusi 154007, People's Republic of China. Electronic address: jiangxin@jmsu.edu.cn.
⁶ State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, People's Republic of China. Electronic address: zhaob@mail.jlu.edu.cn.

PMID: 35863183
DOI: 10.1016/j.saa.2022.121643

Abstract

Considering the variable valence characteristics of rare earth elements, they can be in a variety of valence forms coexistence. Doping of rare earth element with different valence states may produce different energy levels to tune the semiconductor energy band structure. We utilize rare earth element Ce doping TiO₂ for the development of high-performance semiconductor surface-enhanced Raman scattering (SERS) substrates based on an energy-level tuning strategy. Ce doping not only forms multiple energy levels including Ce³⁺ and Ce⁴⁺ metal doping energy levels in the bandgap of TiO₂, but also enriches the surface state level of TiO₂ itself, which together promote the separation of photogenerated carriers and improve charge transfer efficiency between substrates and absorbed molecules. This endows TiO₂ semiconductor substrate with a higher SERS enhancement factor, which can reach 2.2 × 10⁶. The detectable concentration of methylene blue can be as low as 10^-10 mol/L. Moreover, the semiconductor substrate exhibits excellent uniformity and stability. This study not only provides a new strategy to develop excellent semiconductor SERS substrate with multiple energy levels, but also lays the foundation for promising practical application of semiconductor substrate.

Keywords: Ce-doped; Multiple energy levels; SERS; Semiconductor.