The Study of Quantum Dot Sensitized Solar Cell Prepared by Sol-Gel Method

• Main Authors: Kuan-Hong Cheng, 鄭冠宏
• Other Authors: 斯頌平
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/96409986839405125228

碩士 === 國立中興大學 === 物理學系所 === 104 === The quantum dots semiconductor sensitized solar cell is prepared by incorporation of the sol-gel and the chemical bath deposition methods. The CdS quantum dot which is prepared by the chemical bath deposition method is mixed with titanium isopropoxide. The solution is then spin coated on the substrate glass that is precoated with a thin dense TiO2 layer. X-ray, SEM and AC impedance analyzer are used to characterize the structure and morphology of the cell. According to the measurements of the I-V curves of the cells, the cell having the highest conversion efficiency is prepared using sodium sulfide as precursor, the molar ratio of Ti, Cd, and S is 1:1:1, pH value of the solution is 4, the heat treatment temperature is 450℃, the time of the heat treatment is 2 hours, and the soaking time to eliminate of Na+ ions is 4 minutes. The best performance cell has efficiency 0.213%, open circuit voltage 0.37 V, and short circuit current density 1.37 mA/cm2. The SEM image for the cell having the highest efficiency shows microstructure of small TiO2 particles aggeragating to larger particles and with small holes between them. The exchange current density, electron diffusion length and the recombination time of electron and hole are obtained by analyzing the ac impedance spectra. The results indicate that the recombination time of electron and hole is the most important factor affecting the efficiency of the cell.