Progress of Atmospheric Screen-printable Cu Paste for High Efficiency PERC Solar Cells

The metallization of solar cells remains a dominating factor for the total cost of solar cell manufacturing and must be reduced. A prime candidate to replace the traditional Ag is Cu since it is close in conductivity but about 100 times lower cost. However, the oxidation of Cu in atmosphere and its diffusion into Si have been troublesome factors preventing its implementation. These two challenges were considered to formulate the thick film Cu paste and the 19.4% efficiency, fill factor of 76.02%, short-circuit current density of 39.0 mA/cm2 and open-circuit voltage of 654.4 mV, show these challenges have been overcome.