Oxidation-resistant Cu-based metallisation for Si solar cells

Herein, the oxidation resistance effect of B on the high-temperature sintering of Cu-based metallisation for crystalline Si solar cells is described. Atmospheric sintering of B-containing Cu–Ag core-shell paste printed on a Si wafer is performed at high temperatures (up to 800°C). The oxidation of Cu is effectively prevented by B, affording a brown bulky Cu–Ag film with low electrical resistivity (order of 10⁻⁶ Ω cm). The Cu–Ag film formation is monitored via microscopic and crystallographic analyses. The Cu–Ag film exhibits increased electrical conductivity with increasing B content from 0 to 5 wt.%. X-ray photoelectron spectroscopy data reveal that the B₂O₃ formed on the Cu–Ag film surface prevents external oxygen diffusion into the bulk. The developed paste is applied to a crystalline Si solar cell, affording a maximum efficiency of 17.55%. These results show the practical applicability of Cu-based electrodes in the solar cell industry.