TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Structure: The graphene-nanoparticle structure further comprises at least one second graphene layer and at least one second nanoparticle layer alternately disposed on the first nanoparticle layer. In the photocatalytic structure, the nanoparticle layer comprises several nanoparticles configured to have a peak efficiency of optical absorption in a band of visible light. Preferred Method: In the method (M1), forming the first graphene layer comprises: synthesizing graphene on a second substrate having a metal catalyst layer thereon using a chemical vapor deposition method to form a synthesized graphene; and transferring the synthesized graphene onto the first substrate, where the second substrate is a copper foil. The method (M1) further involves: coating polymethyl methacrylate (PMMA) on the synthesized graphene; removing the copper foil before transferring the synthesized graphene onto the first substrate; surface treating the first graphene layer to impart positive electric charges on it; forming a second graphene layer on the first nanoparticle layer; forming a second nanoparticle layer on the second graphene layer; and surface treating the second graphene layer to impart positive electric charges on it. Forming the first nanoparticle layer comprises: forming an aqueous solution comprising the nanoparticles; and aligning the nanoparticles comprised in the aqueous solution onto the graphene layer using a Langmuir-Blodgett method. Forming the second graphene layer comprises: synthesizing graphene using a chemical vapor deposition method on a second substrate having a metal catalyst layer formed on it; and transferring the synthesized graphene onto the first nanoparticle layer. Preferred Components: The first and second graphene layers have a positive electric charge. The first nanoparticle layer comprises several nanoparticles containing metal, metal oxide, semiconductor, or polymer. The nanoparticle layer comprises several gold nanoparticles.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The first substrate in the method (M1) is a polyethylene terephthalate substrate. EXAMPLE - No suitable example given.