There is provided a modality of solar energy conversion comprising: a plurality of cores consisting essentially of a wide band-gap material, wherein each core has at least one bisectional dimension that does not exceed 100 nanometres; a plurality of graphene shells, each consisting essentially of graphene, and each being disposed about at least a substantial portion of a respective core to form a core/shell structure; a first electrical pathway comprising a conducting base electrically connected to the cores, but not to the shells, at a first end of the core/shell structure; a second electrical pathway electrically connected to the graphene shells, but not to the cores, via graphene layers at a second end of the core/shell structure, wherein: in each core/shell structure, the wide band-gap material and the graphene shell form a photovoltaic junction, the first and second electrical pathways are arranged to couple to an electrical load.