Effect of the Pb–Te–B–O system glass frits in the front contact paste on the conversion efficiency of crystalline silicon solar cells

In the present paper, many monocrystal silicon (Si) solar cells are produced by screen printing a front contact paste prepared with crystalline silver particles, a series of glass frits with the different lead oxide (PbO) contents in Pb–Te–B–O system glass, and an organic medium. Under scanning electron microscopy, the selective etching of cells screen-printed by pastes containing the glass frits of different PbO contents from low to high (37.2–52.5 mol%) reveals the corrosion degree of antireflection coating and the growth of silver crystallite microstructures on Si substrate. When the PbO content is 42.7 mol% in glass frits, the silver crystallites of optimal size were formed to make the conversion efficiency of cells best. By comparing the cross-section microstructures of solar cells, the different transition temperatures (T_g = 283–546 °C) of glass frits are found to have a substantial impact on wetting behavior during the firing cycle. When the glass T_g is medium (T_g = 393 °C), the optimal glass layer will be obtained to derive photoelectrons smoothly.