LAUSR

Novel Pb-free Ag paste with a TeO2 based glass frit for front contact electrodes of crystalline silicon solar cells were prepared. The influence of TeO2 content (44–80 mol%) on thermal properties, structure and chemical durability of TeO2 based glass was investigated. The thermal expansion coefficient decreased firstly when the TeO2 content reached 60 mol%, then increased with further increasing TeO2 content. The glass transition temperatures are 400–450 °C and melting temperature was as low as 800 °C. The weight loss of Te-3 glass specimen value is 0.28 × 10−3 mg/cm2, improving the chemical durability of the TeO2 based glass system. In addition, morphology of TeO2 based Ag films sintering at various temperatures were also investigated. The grain size of the Ag film increased when the content of glass frit increased, and grain boundaries for sintering TeO2 based Ag pastes was obvious. The host elements of Ag, Te, Bi, and O in AT-3 specimens were almost homogeneously distributed. The amounts of SiO2 formed when the Ag films were firing at 750 °C, indicating the etching of SiNx layer by TeO2 based glass frit. The specific resistivity of silver conducting films with 3 and 5 wt% glass materials of silver component were 3.1 and 3.7 µΩ cm, respectively.