Unification of rheology of thixotropic yield stress fluids and screen printing properties of pastes

Abstract

At present, the electrode width of solar cells has been successfully reduced to less than 20 µm. Ensuring its morphology and aspect ratio remains a major challenge to further reducing the electrode width, which puts higher requirements on the performance of the paste. Previous studies have focused less on selecting organic carrier components and the relationship between carrier and paste printing suitability. Therefore, in this study, considering the wettability of the solvent to the silicon wafer, the solubility to the binder and the boiling point, the selection method of the mixed solvent for the organic carrier was given. The Herschel-Buckley model was introduced to characterize the flow behavior of the organic carrier. Furthermore, the model parameters were unified with the printability of the paste and the organic carrier model parameters corresponding to the paste with good printability were contributed. The results showed that when the consistency index (K) was 21.883 and the exponent (n) was 0.1545, the aspect ratio of the electrode was the largest. When the yield stress (5.38 Pa) and thixotropic loop area (707.71 Pa s−1) were the largest, the morphology of the electrode was the most regular.