Scalable all-ceramic nanofilms as highly efficient and thermally stable selective solar absorbers

The pressing demands for next-generation concentrating solar power drive the pursuit of high-efficiency, thermally stable, and scalable spectrally selective absorbers. Multilayer metal/ceramic nanofilms are promising candidates owing to their strong sunlight absorption provided by extremely simple configurations and facile fabrication. However, the commercial success of such absorbers is still hindered by their unsatisfactory spectral selectivity and high-temperature stability associated with metal/ceramic interfaces. Here we first propose an allceramic TiN/TiNO/ZrO2/SiO2 absorber with highly selective absorption, i.e., a high solar absorptance (92.2%) yet an ultralow thermal emittance (17.0% at 1000 K), producing an unprecedented solar-thermal conversion efficiency (82.6% under 100 suns). Remarkably, the absorber shows great thermal stability even after long-term (150 h) annealing at 1000 K, boosting the operating temperature of conventional multilayer absorbers by at least 227 K. The efficient and stable all-ceramic absorber can be readily produced in quantity via low-cost processes, rendering it attractive for high-temperature solar-thermal technologies.