나노입자 적층 시스템을 이용한 염료감응 태양전지의 제조

Abstract

TiO2 powders for dye-sensitized solar cell (DSSC) were sprayed on indium tin oxide (ITO) glass using nano-particle deposition system (NPDS) and calcined at 500 ℃ for making interconnections among TiO2 particles. NPDS is one of the novel deposition systems for ceramic and metallic powders on substrate at room temperature by means of accelerating particles to supersonic velocity. In this study, TiO2 powders were deposited via NPDS for DSSC to study its effects. Conventional method to prepare working electrode uses TiO2 paste where nano sized TiO2 powders was mixed with several binders and solutions using screen print TiO2 layers formed by this paste type, however, often induce low adhesion problem between the substrate and TiO2 layers, degrading energy efficiency of DSSC. Moreover, the fabrication of TiO2 paste needs numerous steps to make powders to be dispersed. To overcome these issues, TiO2 powders were directly sprayed on ITO glass using NPDS. During deposition process, nano-sized TiO2 particles were densely deposited and its cell properties were improved without any adhesion problems. To improve porosity and make scattering layers, commercial nanocrystalline TiO2 powders with different sizes were alternately deposited. Moreover, powders with different size are mixed and they were deposited on the TCO (Transparent Conductive Oxide) glass. The results indicated that DSSC with TiO2 layer composed of different particle size had better cell performance than the cells assembled with single-sized TiO2 particles. Furthermore, the cell with TiO2 layers deposited by NPDS method followed by paste method was used to compare the properties with the cell fabricated only by NPDS. Finally, the light conversion efficiency of 3.5% was obtained for the sample deposited by NPDS followed by paste method. That indicated that NPDS is a proper way to improve density of the TiO2 layers, by improving the electron diffusion rate.