Effect of Glass Frits Amount on Atmospheric Sintering Behavior and Characteristics of Electrode Produced by Copper–Phosphorus Alloy

In this study, we evaluate the atmospheric sintering behavior and characteristics of electrodes produced by copper-phosphorus (Cu-P) alloy paste containing various amounts of B₂O₃-Bi₂O₃-SiO₂ glass frits. We demonstrate the need for a certain extent of glass frits to expand the applicable temperature for use of Cu-P alloy paste shifted to the higher temperature side, where commercial pastes for crystalline silicon (Si) photovoltaics are sintered, although the minimum electrical resistivity of the Cu-P alloy electrode increased by increasing the amount of glass frits. Based on the characteristics of the Cu-P alloy electrode, the need to expand the Cu crystal network and prevent the oxidization of generated Cu has emerged to reduce electrical resistivity. A crystalline BiPO₄ was formed in the sintered Cu-P alloy electrode, which suggests a reaction between partially crystallized glass frits and P₂O₅ generated from Cu-P-O glass derived from the Cu-P alloy that has occurred. Subsequently, the sintering behavior of Cu-P alloy paste, including the glass frits, was discussed based on the results of X-ray diffraction, transmission electron microscopy, scanning transmission electron microscopy energy-dispersive X-ray spectroscopy, and electron energy loss spectroscopy.