Effect of glass frit in Ag paste on the electrical properties of front-side Ag contacts for crystalline-silicon solar cells

Abstract

The effect of glass frit, used in front-side silver pastes, on the electrical properties of front-side silver contacts in silicon solar cells was studied. Glass frits with the same composition but three different degrees of crystallization were prepared by introducing some nucleating agents to provide nucleation sites for the formation of the crystal structure of the glass-frit. The phase structure of the glass frits was characterized using X-ray diffraction. The Ag–Si contacts were investigated using scanning electron microscopy, and the results indicated that glass frit with a moderate crystallization degree facilitated to acquire optimal size crystalline Ag, which was distributed uniformly in the glass layer and silicon substrate. Therefore, an excellent metallized contact was achieved. In addition, the particle size and proportion of glass frit in the paste also had an impact on the electrical properties of the solar cells. The results demonstrated that a silver paste consisting of 3 wt% crystalline glass frit with a particle size of 3.12 μm not only ensured sufficient adhesion of the silver electrode, but also improved the Ag–Si contact to enhance the conversion efficiency of the solar cells.