Nanostructured thin films for solar selective absorbers and infrared selective emitters

•A low cost pathway to realize 2D nanophotonic molybdenum crystals is presented.•These materials can be used as selective solar absorbers and IR emitters.•The fabrication is based on the etching of a deposited columnar film.•Solar absorptance is increased up to 99% with respect to the solar spectrum.•The optical function can also be used to build selective infrared emitters.

Solar technologies require improved material performances or new materials functions, either to improve energy capture or to develop new conversion principles. This work presents a low cost pathway to realize 2D nanophotonic molybdenum crystals having a transition in their optical properties with a tunable cut-off wavelength. These nanostructured materials have a dual function. They can be used as selective solar absorbers and/or selective infrared emitters. This novel pathway for producing low cost nanostructured materials creates new opportunities for solar capture in Concentrated Solar Power, Solar Thermophotovoltaics, Solar Thermo-Electrical Generators and for infrared emission control in thermophotovoltaic technologies.