| 摘要 |
A glass substrate for CIGS solar cells of the present invention is produced by a selenization method. The ratio of Ca + Sr + Ba in the surface layer of the glass substrate to that in the inner part is 0.7 or less. The ratio of the Na2O content in the glass substrate surface to that in the inner part is 0.4-1.1. The ratio of Na in the surface layer of the glass substrate before a heat treatment to that after the heat treatment is 1.1 or more. At a depth of 5,000 nm or more from the glass substrate surface, the glass substrate contains, in mass percentage based on oxides below, 50-72% of SiO2, 1-15% of Al2O3, 0-10% of MgO, 0.1-11% of CaO, 0-13% of SrO, 0-11% of BaO, 1-11% of Na2O, 2-21% of K2O, 0-10.5% of ZrO2, 4-25% of MgO + CaO + SrO + BaO, 2-23% of CaO + SrO + BaO and 8-22% of Na2O + K2O, while satisfying Na2O/(CaO + SrO + BaO) <= 1.2. The glass substrate for CIGS solar cells has a glass transition temperature of 580°C or more and an average thermal expansion coefficient of from 70 × 10-7 /°C to 100 × 10-7 /°C. The glass substrate is able to achieve a good balance between high power generation efficiency and high glass transition temperature. |
