Fabrication Of Ordered Porous Anodic Alumina With Large Interpore Distances And Alumina Substrate

Ordered aluminum substrate is widely used in solar cells, in order to prepare highly ordered, consistent with the large diameter aluminum substrate structure, the paper sudies the traditional porous anodic aluminum oxide (Porous Anodic Alumina, PAA) preparation methods based on the comparative study of the advantages and disadvantages of the conventional preparation techniques PAA, and then by UV nanoimprint and hot stamping technology, we explores the preparation of highly ordered large aperture PAA and aluminum substrates. The detailed research contents and results are as follows:First of all, studying the traditional preparation technology of the anodic alumina. The preparation of PAA with small interval in oxalic acid and sulfuric acid based electrolytes is studied for porous anodic alumina with the large interval to provide technical support.Secondly, preparation of ordered PAA templates with ultra-large interpore distances using ultrahigh voltages. This paper explored the possibility of preparation of PAA with large intervals in mixed ethylene glycol acid and phosphoric/citric acid system based electrolytes. The dependence of pore intervals and the thickness of the barrier layer on anodizing voltages are systematically investigated. It is found that the highest voltage can reach 800 V, at the same time, the barrier layer increase with the voltages and the barrier layer-to-voltage ratio in the mixed acid is 0.9- 1.0 nm V-1. the cellular interval of PAA increase with the voltages and in the high voltage (600-800 V), the intervals-to-voltage ratios in the mixed acid are 2.34-2.55 nm V-1, so that cellular interval up to 1400-2036 nm. Although the structure of the prepared aluminum substrate is irregular, it is under nano-imprinting technologies of the prepration of highly ordered, periodic structure aluminum substrate laid the foundation.Once again, explore nano-imprint process conditions. From three aspects including the template selection, the photo-resist coating, uv-exposure time, explore the UV nano-imprinting process; from hot holding time, pressing temperature, stripping temperature, explores the hot embossing process. It was demonstrated that using PDMS as template in UV nano-imprint lithography process, photo-resist spin coating parameters were 10s,500rpm; 50s,3000rpm and the UV exposure time was 4 min. The holding time of hot embossing was 10 min, pressing temperature was 220℃, demolding temperature was 80℃.Finally, preparation of highly ordered aluminum templates with ultra-large interpore distances. In this paper, nano structure on the master template,though a series of transfer, can be more completely transfer the orderly pattern to the aluminum substrate by combines with thermal printing and UV nano-imprint., and thus guide the growth of porous anodic alumina prepared a highly ordered PAA template. At the same time release treatment on PAA, the surface of the aluminum foil was constructed aluminum pits quasi periodic structure with period 1000 nm..