Photothermal heating and heat transfer analysis of anodic aluminum oxide with high optical absorptance.

Photothermal heating with metallic nanostructures has the unique property of generating heat at the nanoscale owing to plasmon resonances. In this study, the heat transfer of anodic aluminum oxides (AAOs) coated with plasmonic titanium nitride (TiN) of 80 nm thickness are experimentally, numerically, and analytically studied, wherein TiN photothermally generated heat. High optical absorptance and photothermal heating efficiency are observed for the samples with pore sizes in the range of 161-239 nm, and the sample with the pore size of 239 nm exhibits the highest absorptance and photothermal heating efficiency. In addition, the numerical and analytical heat transfer analyses using the effective thermal conductivities for AAO-TiN samples are in reasonable agreement with experimental results, indicating the validity of effective thermal conductivities, which consider the periodic nature. These results can be extended to design other optically absorbing periodic structures for photothermal heating applications.