Presentation Information
[23a-11F-10]Optical light trapping in plasmonic free a-MoO3 nanowires for surface enhanced Raman scattering
〇(D)Jiaqi YANG1, Tang DANG1, Shuting MA1, Siyi TANG1, Yan DING1, Munetoshi SEKI1, Hitoshi TABATA1, Hiroaki MATSUI1 (1.Univ. of Tokyo)
Keywords:
SERS,plasmonic-free,light scattering
Surface-enhanced Raman scattering (SERS) amplifies molecular Raman signals utilizing substrates, essential for precise surface analysis across various disciplines. Historically, the electromagnetic mechanism (EM), relying on surface plasmon resonance, has been pivotal in achieving highly sensitive SERS by employing metallic nanostructures. Conversely, oxide semiconductors like TiO2 and Cu2O elicit SERS effects through a chemical mechanism (CM), entailing a charge transfer from oxides to molecules, which typically yields weaker SERS signals. Recent advancements have introduced structural resonances, including Mie-related resonances, as alternative routes to bolster Raman signal enhancement.
In this presentation, we unveil cutting-edge SERS platforms utilizing α-MoO3 nanowires (NWs), distinguished from conventional CM processes seen in semiconductor materials. The NW specimens were synthesized via a catalyst-free vapor-solid method. An enhancement factor of 2×108 was recorded for NWs with precise stoichiometric composition, which demonstrated significant visible range light scattering. In contrast, non-stoichiometric NW specimens exhibited reduced SERS activity due to diminished light scattering and the presence of visible light absorption. The observed SERS performance correlated with light scattering events. Light transport within the NW specimens was notably influenced by mesoscopic interference akin to Anderson-like localization. Moreover, localized electric fields emerged on the NW surface, influenced by the excitation wavelength, in a manner reminiscent of the SERS response. These optical behaviors suggest the electromechanical (EM) process is crucial in enabling plasmonic-free SERS applications with α-MoO3, offering new avenues for biosensing platforms and machine-learned SERS detection.
In this presentation, we unveil cutting-edge SERS platforms utilizing α-MoO3 nanowires (NWs), distinguished from conventional CM processes seen in semiconductor materials. The NW specimens were synthesized via a catalyst-free vapor-solid method. An enhancement factor of 2×108 was recorded for NWs with precise stoichiometric composition, which demonstrated significant visible range light scattering. In contrast, non-stoichiometric NW specimens exhibited reduced SERS activity due to diminished light scattering and the presence of visible light absorption. The observed SERS performance correlated with light scattering events. Light transport within the NW specimens was notably influenced by mesoscopic interference akin to Anderson-like localization. Moreover, localized electric fields emerged on the NW surface, influenced by the excitation wavelength, in a manner reminiscent of the SERS response. These optical behaviors suggest the electromechanical (EM) process is crucial in enabling plasmonic-free SERS applications with α-MoO3, offering new avenues for biosensing platforms and machine-learned SERS detection.