This invention provides an inorganic coating-protected unitary graphene material article for concentrated photovoltaic cell heat dissipation. The article comprises at least a layer of unitary graphene material having two primary surfaces and an electrically non-conducting layer of inorganic coating deposited on at least one of the primary surfaces, wherein the unitary graphene material is obtained from heat-treating a graphene oxide gel at a heat treatment temperature higher than 100° C. and contains chemically bonded graphene molecules or chemically merged graphene planes having an inter-graphene spacing no greater than 0.40 nm, preferably less than 0.337 nm, and most preferably less than 0.3346 nm.