Effect of the Molar Ratio of B_2O_3 to Bi_2O_3 in Al Paste with Bi_2O_3-B_2O_3-ZnO Glass on Screen Printed Contact Formation and Si Solar Cell Performance

摘要

In this study, eco-friendly Pb-free Bi_2O_3-B_2O_3-ZnO glass frits were chosen as an inorganic additive for the Al paste used in Si solar cells. The effects of the molar ratio of Bi_2O_3 to B_2O_3 in the glass composition on the electrical resistance of the Al electrode and on the cell performance were investigated. The results showed that as the molar ratio of Bi_2O_3 to B_2O_3 increased, the glass transition temperature and softening temperature decreased because of the reduced glass viscosity. In Al screen-printed Si solar cells, as the molar ratio of Bi_2O_3 to B_2O_3 increased, the sheet electrical resistance of the Al electrode decreased and the cell efficiency increased. The uniformity and thickness of the back-surface field was significantly influenced by the glass composition.