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 B 2 O 3 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.