Surface plasmon resonance imaging (SPRi) was a well-established technique for studying binding kinetics and affinity between biomolecules. Due to the limited spatial resolution, SPRi was mostly compatible with microarrays and biochips. We have been developing an advanced SPR microscopy (SPRM) with a greatly improved spatial resolution of optical diffraction limit, so that one can obtain the SPRM image of single objects from single bacterium to single nanoparticles. The SPRM contrast of single nanoparticles depends on the size, the refractive index of the nanoparticles, as well as the distance between the nanoparticles and the substrate. This label-free technology allows us to do many exciting explorations of its application in nanoscience, e.g. nanocatalysis, nanoelectrochemistry and nanosensing etc. We have recently adopted this SPRM technique to investigate the electrochemical and photochemical processes occurring on single nanoparticles. For example, we recently employed SPRM to image Li-ion insertion/extraction rate of single LiCoO<sub>2</sub> nanoparticles during electrochemical lithiation/de-lithiation processes, from which the phase transition and Li-ion diffusion kinetics can be quantitatively resolved in a single nanoparticle, in operando and high throughput manner. Moreover, photocatalytic hydrogen generation rate of single CdS nanoparticles were determined by visualizing nanosized hydrogen bubbles with SPRM. These studies have demonstrated the capability of advanced optical imaging techniques to interrogate the chemical activity at single nanoparticle levels.

Plasmonic imaging of electrochemical and photochemical activity of single nanoparticles

256th National Meeting (2018)

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