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.