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Hydrogen‐Doping‐Induced Metal‐Like Ultrahigh Free‐Carrier Concentration in Metal‐Oxide Material for Giant and Tunable Plasmon Resonance
Author(s) -
Zhu Qing,
Jiang Shenlong,
Ye Ke,
Hu Wei,
Zhang Jiachen,
Niu Xiaoyou,
Lin Yunxiang,
Chen Shuangming,
Song Li,
Zhang Qun,
Jiang Jun,
Luo Yi
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202004059
Subject(s) - materials science , plasmon , doping , surface plasmon resonance , oxide , raman spectroscopy , metal , noble metal , rhodamine 6g , nanomaterials , nanotechnology , optoelectronics , nanoparticle , molecule , optics , chemistry , physics , organic chemistry , metallurgy
The practical utilization of plasmon‐based technology relies on the ability to find high‐performance plasmonic materials other than noble metals. A key scientific challenge is to significantly increase the intrinsically low concentration of free carriers in metal‐oxide materials. Here, a novel electron–proton co‐doping strategy is developed to achieve uniform hydrogen doping in metal‐oxide MoO 3 at mild conditions, which creates a metal‐like ultrahigh free‐carrier concentration approaching that of noble metals (10 21 cm −3 in H 1.68 MoO 3 versus 10 22 cm −3 in Au/Ag). This bestows giant and tunable plasmonic resonances in the visible region to this originally semiconductive material. Using ultrafast spectroscopy characterizations and first‐principle simulations, the formation of a quasi‐metallic energy band structure that leads to long‐lived and strong plasmonic field is revealed. As verified by the surface‐enhanced Raman spectra (SERS) of rhodamine 6G molecules on H x MoO 3 , the SERS enhancement factor reaches as high as 1.1 × 10 7 with a detection limit at concentration as low as 1 × 10 −9 mol L −1 , representing the best among the hitherto reported non‐metal systems. The findings not only provide a set of metal‐like semiconductor materials with merits of low cost, tunable electronic structure, and plasmonic resonance, but also a general strategy to induce tunable ultrahigh free‐carrier concentration in non‐metal systems.