Method for preparing porous alumina photonic crystal film with high-saturation structural color

The invention relates to a method for preparing a porous alumina photonic crystal film with high-saturation structural color. The method comprises the following steps that a high-purity aluminum sheetis annealed, polished, washed and then used as an anode, graphite is used as a cathode and immersed in an oxalic acid solution, constant potential sinusoidal pulse is used for performing the first time of anodic oxidation, and photonic crystal is prepared; and after washing, the high-purity aluminum sheet is placed in the oxalic acid solution and subjected to the second time of anodic oxidation by using a large voltage supplied by a direct current stabilized power source to obtain the anodized alumina photonic crystal template with the high-saturation structural color. The method can observethe structural color with higher saturation without removing an aluminum substrate and depositing other materials in an alumina film, and further expands the application of the photonic crystal structural color in the fields o