Fabrication of Cu-Based Quaternary Compounds PhotoVoltaic Devices

• Main Authors: Jheng, Bao-Tang, 鄭寶堂
• Other Authors: Wu, Meng-Chyi
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/34g94g

博士 === 國立清華大學 === 電子工程研究所 === 103 === I-III-VI2 chalcopyrite compounds, particularly copper indium gallium selenide Cu(In,Ga)Se2, are effective light-absorbing materials in thin-film solar cells. The first topic of this dissertation focuses on the improvement of device performance. We fabricated ZnO nanorod array antireflection coating on thin film Cu(In,Ga)Se2 solar cells by a cheap and simple hydrothermal route. The weighted reflectance was reduced from 13.5 to 12.6%. Highest increases in both the photocurrent of 29% and the solar cells efficiency of 21.9% were achieved. The second topic of this dissertation focuses on the post-treatment effect on the solar devices. The effects of air annealing, light soaking, and heat–light soaking on cell performances were investigated for Cu(In,Ga)Se2 thin-film solar cells. It was found that the heat–light soaking, a combination of light soaking and air annealing is the most effective process for improving the cell performance of cadmium (Cd)-free solar devices. The optimum cell efficiencies of Cu(In,Ga)Se2 solar cells were greatly improved from 7.8% to13.0% after heat–light soaking treatment at 130oC, under standard AM1.5, 100mW/cm2 illumination, for 80min. Recently, Cu2ZnSnS4 and Cu2ZnSnSe4 are particularly attractive because Sn and Zn are naturally abundant in the Earth’s crust. In the three topic of this dissertation, we describe Cu2ZnSnS4 films that are instead deposited by RF magnetron co-sputtering from from a quaternary alloy target and a ZnS binary target without any additional sulfurization. The preliminary conversion efficiency and fill factor for the non-sulfurization based solar cells are 6% and 48%, respectively, although the processing details are not yet optimized. Our simple and safe approach reported here represents the first step toward realizing low-cost, large-area, high efficiency solar cells.