A method and structure for heat transport, cooling, sensing and power generation is described. A photonic bandgap structure (3) is employed to enhance emissive heat transport from heat sources such as integrated circuits (2) to heat spreaders (4). The photonic bandgap structure (3) is also employed to convert heat to electric power by enhanced emission absorption and to cool and sense radiation, such as infra-red radiation. These concepts may be applied to both heat loss and heat absorption, and may be applied to heat transport and absorption enhancement in a single device.