Pore Size Dependence of Optical Absorption Enhancement in Porous Anodic Aluminum Oxide

Three samples of high ordered AAO template were prepared via a two-step anodization procedure, the pore size was modified during the pore-widening process to tune the pore diameter to 50, 70, and 90 nm. Scanning electron microscopy (SEM) was adopted to gauge the pore diameter and the cell unit of the periodical hexagonal structure of the prepared AAO templates. In addition, the UV-vis spectrometer shows the variation of the absorbance spectrum for each pore size of the prepared AAO templates. To prove that the pore diameter (PD) and the intermediate layer (IL) could enhance the absorbance of the materials, a Lumerical FDTD solution was used by involving the exact experimental conditions of the AAO template. The resulting data show that a specific pore diameter with a specific intermediate layer can improve the absorbance spectrum of the materials. Thus, the results could serve the applications related to solar energy conversion (antireflective and photocatalyst) and photonics.