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Ultrathin Molybdenum Dioxide Nanosheets as Uniform and Reusable Surface‐Enhanced Raman Spectroscopy Substrates with High Sensitivity
Author(s) -
Wu Hongrong,
Zhou Xiaocheng,
Li Jidong,
Li Xuemei,
Li Baowen,
Fei Wenwen,
Zhou Jianxin,
Yin Jun,
Guo Wanlin
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201802276
Subject(s) - materials science , raman spectroscopy , substrate (aquarium) , molybdenum , surface plasmon resonance , surface enhanced raman spectroscopy , chemical vapor deposition , nanotechnology , noble metal , chemical engineering , spectroscopy , nanomaterials , metal , nanoparticle , oxide , detection limit , raman scattering , chemistry , metallurgy , optics , oceanography , physics , engineering , quantum mechanics , geology , chromatography
Metal oxides have advantages over the traditional noble metals to be used as substrate materials for surface‐enhanced Raman spectroscopy (SERS) with low cost, versatility, and biocompatibility, but their enhancement factors are generally quite low with a poor limit of detection. Here, ultrathin molybdenum dioxide (MoO 2 ) nanosheets synthesized by chemical vapor deposition demonstrated in large area are used as SERS substrates with superior signal uniformity in the whole area with a limit of detectable concentration down to 4 × 10 −8 m and enhancement factor up to 2.1 × 10 5 , exceeding that of 2D materials and comparable to that of noble metal films. More practically important, the planar MoO 2 substrate is more robust than noble metals and shows excellent reusability and uniformity, which is usually prohibited for nanostructured or nanoparticle‐based metal oxide substrates. The enhancement is mainly attributed to the surface plasmon resonance effect as evidenced by the first principle calculations and UV–vis absorption spectroscopy characterization, which can be further increased by decreasing the thickness of the MoO 2 nanosheets. The overall superior performance makes the MoO 2 nanosheets an ideal substrate for practical SERS applications.