KCS

The ZnO nanoparticle was synthesized by sol-gel method using zinc acetate and lithium hydroxide ethanolic solution. Various concentration ratios [Zn]/[OH] were applied for the synthesis, which showed the particle size and morphology of ZnO were changed as a function of [Zn]/[OH]. When the ratio is as large as 3, the particle size was calculated around 30nm from the peak broadening by XRD. As the ratio decreases, various secondary structures such as platelet, 200nm-nanoball, networked cluster have been observed consecutively. Among dye-sensitived solar cell constructed with such ZnO materials, 200nm-ZnO nanoball electrode consisting of sparsely packed 10nm sized primary particles, exhibited the energy conversion efficiency as high as 5.76% with the thickness of 20㎛. The morphology and particles of ZnO powder and electrode was measured by FE-SEM and FE-TEM. The cell performance of nanoball ZnO electrode was analyzed with J-V measurement, electrochemical impedance spectroscopy and IPCE.