Effect of composition of front-electrode-paste glass on electrical performance of multicrystalline silicon solar cells

In this study, the effects of Si/Pb ratio of Pb–Te–Si–O glasses on the electrical performance of multicrystalline Si solar cells were investigated. We first studied the relationship between the properties of glass frit (such as transition temperature (Tg), crystallization tendency, and aggressiveness) and the Si/Pb ratios. Then, the influence of glass frit Tg on the structure of the contact interface, quality of ohmic contacts, and solar cell electrical performance was investigated. The results showed that the cell based on glass frit produced at moderately low Tg, had smaller series resistance and higher photoelectric conversion efficiency than those based on lower Tg and higher Tg glass frits. The optimal glass frit Tg was 289.6 °C; glass frits can form dense and thick films, which can reduce the bulk resistance of the grid line. At the same time, glass frits can reduce the Ag crystallite size to prevent high junction leakage and shunting of shallow emitters, and probably increase the concentration of Ag crystallites and Ag colloids to help tunnel the thinner glass layer. This led to formation of good ohmic contacts and conductive chains. All these features contributed to reach the best values of photoelectric conversion efficiency (18.628%) and series resistance (0.0019 Ω).