An idea of using nanofilm-nanoparticle-electron donor composites as the energy sources to sub stitute oil and gas has been developed by American, Japanese, and Chinese scientists. The underlying princi ple is as follows: under the effect of visible light, electrons are knocked out from nanoparticles; absorbed by the nanofilm, which acts as a reservoir; and, finally, attached to the donor; then, the cycle is repeated. In this review, the electronic structure, properties, and interactions between all the nanocomposite components, as well as their interaction with the solvent and protective shell, are analyzed. The interactions are shown to reduce the efficiency of a nanocomposite used as a photogalvanic cell.