Annular Ti-Al2O3-Ti triple-layer stacked composite microstructure solar absorber

The increasing global energy demand has intensified the pursuit of efficient and clean energy sources, particularly solar energy. This study introduces a novel solar absorber design consisting of three periodic layers of Ti-Al2O3-Ti circular composites deposited on a Ti-Al2O3 composite film substrate. The absorber demonstrates exceptional performance across the solar spectrum from 240  nm to 3354  nm, achieving an average absorptance exceeding 97.8 % and a minimum absorptance over 90 % within a bandwidth of 3114  nm. Utilizing only titanium (Ti) and alumina (Al2O3), both of which have high melting points, the absorber exhibits excellent thermal stability at elevated temperatures. Moreover, the absorber maintains high absorption efficiency regardless of incident angle and polarization and shows robustness over a wide range of manufacturing tolerances, highlighting its practical applicability. The spectral absorption closely aligns with the solar spectrum, sustaining high efficiency even at large incidence angles and varying polarizations. These results suggest that the proposed absorber has significant potential for applications in solar cells, solar collectors, thermal emitters, and photothermal conversion technologies.