Ag nanoparticle decorated graphene oxide: Fluorescence quenching and surface enhanced raman scattering (original) (raw)
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physica status solidi (a), 2020
Layer‐by‐layer photocatalyst films made of TiO2 nanoparticles (TiO2NP) assembled with both poly(sodium 4‐styrenesulfonate) (PSS) and graphene oxide (GO) are used for the photodeposition of plasmonic Ag nanoparticles (AgNPs) and subsequently used in surface‐enhanced Raman scattering (SERS). Both photocatalyst films, TiO2NP/PSS and TiO2NP/GO, are capable of driving the formation of AgNP when they are wetted with a drop of AgNO3 diluted solution and submitted to UV irradiation (254 nm). The photodeposition of AgNP, as monitored by UV–vis spectroscopy, follows a first‐order kinetics process in both films and is slightly faster in the TiO2NP/PSS. In addition, scanning electron microscopy reveals that in the TiO2NP/PSS film, the photodeposited AgNPs are larger and isolated, whereas in the TiO2NP/GO film, they are smaller and highly interconnected. The SERS activity of the substrates is evaluated with rhodamine B. When samples are excited in resonance with rhodamine B absorption (514 nm), ...
Small, 2021
Ag nanoparticles (NPs) modified graphene nanoribbons (GNRs) are proposed to function as the high-performance shared substrates for surface-enhanced Raman and infrared absorption spectroscopy (SERS and SEIRAS). This is realized by modulating the localized plasmonic resonances of Ag NPs in visible region and GNRs in mid-infrared region simultaneously, so as to selectively employ each resonance to acquire SERS and SEIRAS on a single substrate. As a proof of concept, shared substrates are prepared by fabricating GNRs on a Fabry–Pérot like cavity, followed by depositing a thin Ag film with annealing treatment to achieve Ag NPs. Complementary Raman and infrared active vibrational modes of rhodamine 6G molecules can be extracted from the SERS and SEIRAS spectra. By optimizing the dimension of Ag NPs, SERS enhancement factors at the order of 105 can be achieved, which are comparable with or even larger than that of the reported shared substrates. Meanwhile, various polyethylene oxide vibrational modes can be recognized with maximum SEIRAS amplification up to 170 times, which is one order larger than that of the reported graphene plasmonic infrared sensors. Such plasmonic nanosensor with excellent SERS and SEIRAS performance exhibits promising potential for biosensing applications on an integrated lab-on-a-chip strategy.