Influence of the properties of organic media in back-side silver pastes on the electrical performance of polycrystalline silicon solar cells

In this paper, the best composition and ratio of solvents for the organic medium in back-side silver pastes was selected through a series of orthogonal experiments. The results showed that the volatility of the organic medium mentioned above was better than the others. The back-side silver paste prepared using this organic medium had appropriate viscosity (4.36 Pa s) and less residual ash content (0.75 wt%) when the composition of the solid substances in the organic medium was: acrylic resin 3.50 wt%, phenoxy resin 2.30 wt%, and ethyl cellulose 2.40 wt%. The properties of this paste were investigated after it was printed and further sintered to form back-side silver electrodes on solar cells. Scanning electron microscopy images showed that these back-side silver electrodes had a smoother and more dense surface, a more appropriate width and thickness, and closer contact with the silicon wafer and a larger welding tension. As a result, the photoelectric conversion efficiency of the solar cells printed by this back-side silver paste reached 18.06%.