Interplay between electrochemistry and optical imaging: The whole is greater than the sum of the parts

Optical techniques can afford a powerful characterisation of the solid–liquid interface that is composed of an electrode immersed in an electrolyte. While a typical electrochemical measurement such as current intensity is averaged over the entire electrode surface, the access to surface heterogeneity can provide an increased level of information enabling to rationalise and optimise the performance of chemical or biochemical sensors. In this opinion article, we will briefly review the different strategies developed to translate an electrochemical process into a luminescence signal. Also, several key examples will be selected and commented in order to highlight the key advantages of coupling electrochemistry with optical imaging, essentially fluorescence and electrochemiluminescence.