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In this study, we prepared TiO2 powder coated with nano-oxide particles such as Al2O3, SiO2, ZnO by a modified sol-gel method and also investigated the properties of the TiO2 light scattering particles surface-coated by adjusting the concentration and pH.
From SEM images, it was found that TiO2 powders modified with Al2O3 nanoparticles at pH7 condition showed a good adsorption behavior. But TiO2 powders coated with Al2O3 nanoparticles at pH2 condition rarely showed adsorption behavior, and TiO2 powders with Al2O3 nanoparticles at pH12 condition were observed aggregation phenomenon. Also, adsorption behavior shows differences according to concentration conditions. The case of SiO2, TiO2 powders modified with SiO2 nanoparticles at 5.92wt% and 0.018wt% condition showed a good adsorption behavior. But TiO2 powders coated with SiO2 nanoparticles at 0.037wt% condition rarely showed adsorption behavior in SEM images. TiO2 powders coated with ZnO nanoparticles at various pH and concentration conditions rarely showed adsorption behavior in SEM images.
Moreover, we found that the morphological change of TiO2 nanoparticles surface considerably affect back scattering abilities of the light scattering layer by using UV-vis. spectrometer. As a result, we confirmed that the DSSC performance was improved by using TiO2 light scattering layers with morphological change caused by the surface coating.
It was found that dye-sensitized solar cell characteristics fabricated by using modified TiO2 powder were remarkably better than those with unmodified TiO2. The use of single-coated and dual-coated TiO2 the light scattering layers resulted in an increase in both the Jsc value, resulting in increasing the overall power conversion efficiency of the DSSC devices. Experimental results suggest that the surface coating of the light scat tering layer is a way for improving the overall conversion efficiency.
Thesis Advisor: Prof. Sang-Ho Sohn