The present invention provides a novel photoelectrical device for efficient transmission of electrical signals to a neuron. This photoelectrical device comprises one or more charging units for coupling to and stimulating one or more neurons by charge, the charging unit comprising: a nanostructure-based electrode having a surface, which has a predetermined developed surface area for coupling to a neuron and which carries a plurality of photosensitive regions (e.g. quantum dots) interfacing with a biocompatible macromolecule for tuning the relative energy levels between the photosensitive regions and the electrode, as well as for directing the spatial polarity of charge separation the surface being thereby electrically chargeable and dischargeable in response to light excitation of the photosensitive regions, the charges stimulating the neuron when coupled to the surface.