Spatially resolved electrochemistry enabled by thin-film optical interference

Herein, we report an approach with sub-micrometer spatial resolution for studying local electrochemistry based on thin-film optical interference. The spatial resolution is achieved by successive interferometric imaging of a nanochannel membrane coated electrode during an electrochemical (EC) reaction. The EC reaction of redox molecules on the electrode induces variation of the refractive index of the nanochannel membrane, leading to changes of the intensity of interferometric light. Local EC reactions thus can be studied from the optical signal. The refractometry-based approach is versatile and label-free, and has promising application in nanosensing and nanocatalysis. © The Royal Society of Chemistry 2020.