Fine size Pb-based glass frit with spherical shape as the inorganic binder of Al electrode for Si solar cells

Pb-rich PbO–SiO2–B2O3–ZnO glass frits, which are used as an inorganic binder for Al electrodes for backside contact in single-crystalline or polycrystalline Si solar cells, were directly prepared by spray pyrolysis. Spherical glass frits with dense structure and an amorphous phase were prepared by spray pyrolysis at temperatures of 1100 and 1200 °C. The mean diameter and glass transition temperature (Tg) of the glass frits were 0.92 μm and 328.5 °C, respectively. The use of glass frits enhanced the contact between the Al powders in Al films and the films. The addition of glass frits also enhanced the adhesion properties of the conducting Al films. The sheet resistances of Al films with thicknesses of 14 and 37 μm that were formed from Al paste without glass frits at a firing temperature of 900 °C were 50.5 and 29.4 mΩ/sq, respectively, while those of Al films with thicknesses of 15 and 36 μm that were formed from Al paste with glass frits at the same firing temperature were 31.8 and 10.8 mΩ/sq, respectively.