Fabrication of Oxide Ceramics Dendrites for Porous Electrodes by Using Stereolithography

Abstract

Porous oxide ceramics such as zinc oxide are applied for dye sensitized solar cell. This device requires consideration of high surface area, mechanical strengths and porous networks. Thus, we focused on the dendrite structures constructed from micrometer order rods with coordination numbers of 4, 8, and 12. There perfectly controlled structures were fabricated by stereolithography. Variations of the aspect ratios (lattice length to diameter ratios) were adjusted to control the porosity in the range 50–80 vol. % by using computer graphic software. The dendrite models sliced into a series of cross sectional patterns with uniform thickness by using a stereolithographic file format convertor. These numerical data were transferred into the micro processing equipment. High viscosity slurry material was prepared by mixing oxide ceramic powder and photosensitive acrylic resin. This slurry was spread on a flat stage and smoothed. An ultraviolet laser beam was exposed over the deposited layer to create cross-sectional planes. Through layer-by-layer processes, solid components were fabricated. These precursors were dewaxed at 600°C for 2 h at a heating rate of 1.0°C/min and sintered at 1400°C for 2 h at a heating rate of 5.0°C/min in air. The oxide ceramics microstructure was observed using a scanning electron microscope.