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J Am Chem Soc. 2018 Jul 18;140(28):8696-8704. doi: 10.1021/jacs.8b02972. Epub 2018 Jul 5.

1T' Transition Metal Telluride Atomic Layers for Plasmon-Free SERS at Femtomolar Levels.

Author information

1
Department of Electronic Engineering , The Chinese University of Hong Kong , Shatin, N.T., Hong Kong SAR , China.
2
State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology and Guangdong Province Key Laboratory of Display Material , Sun Yat-sen University , Guangzhou 510275 , China.
3
State Key Laboratory of ASIC and System, School of Information Science and Technology , Fudan University , Shanghai 200433 , China.
4
College of Microelectronics, Department of Information Science & Electronic Engineering , Zhejiang University , Hangzhou 310027 , China.
5
Department of Biomedical Engineering , The Chinese University of Hong Kong , Shatin, N.T., Hong Kong SAR , China.
6
School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore.
7
Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics , Jinan University , Guangzhou 510632 , China.

Abstract

Plasmon-free surface enhanced Raman scattering (SERS) based on the chemical mechanism (CM) is drawing great attention due to its capability for controllable molecular detection. However, in comparison to the conventional noble-metal-based SERS technique driven by plasmonic electromagnetic mechanism (EM), the low sensitivity in the CM-based SERS is the dominant barrier toward its practical applications. Herein, we demonstrate the 1T' transition metal telluride atomic layers (WTe2 and MoTe2) as ultrasensitive platforms for CM-based SERS. The SERS sensitivities of analyte dyes on 1T'-W(Mo)Te2 reach EM-comparable ones and become even greater when it is integrated with a Bragg reflector. In addition, the dye fluorescence signals are efficiently quenched, making the SERS spectra more distinguishable. As a proof of concept, the SERS signals of analyte Rhodamine 6G (R6G) are detectable even with an ultralow concentration of 40 (400) fM on pristine 1T'-W(Mo)Te2, and the corresponding Raman enhancement factor (EF) reaches 1.8 × 109 (1.6 × 108). The limit concentration of detection and the EF of R6G can be further enhanced into 4 (40) fM and 4.4 × 1010 (6.2 × 109), respectively, when 1T'-W(Mo)Te2 is integrated on the Bragg reflector. The strong interaction between the analyte and 1T'-W(Mo)Te2 and the abundant density of states near the Fermi level of the semimetal 1T'-W(Mo)Te2 in combination gives rise to the promising SERS effects by promoting the charge transfer resonance in the analyte-telluride complex.

PMID:
29927248
DOI:
10.1021/jacs.8b02972

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