A Novel Ultra-Sensitive Semiconductor SERS Substrate Boosted by the Coupled Resonance Effect

Lili Yang; Yusi Peng; Yong Yang; Jianjun Liu; Haoliang Huang; Bohan Yu; Jimin Zhao; Yalin Lu; Zhengren Huang; Zhiyuan Li; John R Lombardi

doi:10.1002/advs.201900310

A Novel Ultra-Sensitive Semiconductor SERS Substrate Boosted by the Coupled Resonance Effect

Adv Sci (Weinh). 2019 Apr 16;6(12):1900310. doi: 10.1002/advs.201900310. eCollection 2019 Jun 19.

Authors

Lili Yang^{1

2

3}, Yusi Peng^{1

2

3}, Yong Yang^{1

2

3}, Jianjun Liu¹, Haoliang Huang⁴, Bohan Yu^{2

5}, Jimin Zhao^{2

5}, Yalin Lu⁴, Zhengren Huang¹, Zhiyuan Li⁶, John R Lombardi⁷

Affiliations

¹ State Key Laboratory of High Performance Ceramics and Superfine Microstructures Shanghai Institute of Ceramics Chinese Academy of Sciences 1295 Dingxi Road Shanghai 200050 P. R. China.
² University of Chinese Academy of Sciences No.19(A) Yuquan Road Beijing 100049 P. R. China.
³ Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China.
⁴ National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230026 P. R. China.
⁵ Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China.
⁶ South China University of Technology Guangzhou 510640 Guangdong P. R. China.
⁷ Department of Chemistry The City College of New York 160 Convent Avenue New York NY 10031 USA.

Abstract

Recent achievements in semiconductor surface-enhanced Raman scattering (SERS) substrates have greatly expanded the application of SERS technique in various fields. However, exploring novel ultra-sensitive semiconductor SERS materials is a high-priority task. Here, a new semiconductor SERS-active substrate, Ta₂O₅, is developed and an important strategy, the "coupled resonance" effect, is presented, to optimize the SERS performance of semiconductor materials by energy band engineering. The optimized Mo-doped Ta₂O₅ substrate exhibits a remarkable SERS sensitivity with an enhancement factor of 2.2 × 10⁷ and a very low detection limit of 9 × 10^-9 m for methyl violet (MV) molecules, demonstrating one of the highest sensitivities among those reported for semiconductor SERS substrates. This remarkable enhancement can be attributed to the synergistic resonance enhancement of three components under 532 nm laser excitation: i) MV molecular resonance, ii) photoinduced charge transfer resonance between MV molecules and Ta₂O₅ nanorods, and iii) electromagnetic enhancement around the "gap" and "tip" of anisotropic Ta₂O₅ nanorods. Furthermore, it is discovered that the concomitant photoinduced degradation of the probed molecules in the time-scale of SERS detection is a non-negligible factor that limits the SERS performance of semiconductors with photocatalytic activity.

Keywords: energy band engineering; photoinduced degradation; surface‐enhanced Raman scattering; the “coupled resonance” effect; ultra‐sensitive Ta2O5 nanorod substrate.