Investigation of the Chemical Reaction between Silver Electrodes and Transparent Conductive Oxide Films for the Improvement of Fill Factor of Silicon Heterojunction Solar Cells

Abstract

We evaluated the fill factor (FF) degradation mechanism in silicon heterojunction (SHJ) solar cells with high mobility In2O3 film as a high carrier mobility transparent conductive oxide (TCO) film. In particular, we focused on the electrode formation using a high productive screen-printing technique. We found the In2O3 film is easier to be reduced than the traditional TCO such as tin-doped indium oxide (ITO). Thus, the Ag atom inside the electrode is easily oxidized during the cure annealing process and results in higher contact resistance at electrode/TCO interface and deteriorate FF characteristic. We introduced novel cation catalyst additive for paste polymerization which is less reactive with In2O3 and improve the contact resistance by suppressing the silver oxidation. We also demonstrated SHJ cell fabrication and prove the effect of the developed silver paste.