In the photovoltaic industry, screen printing accounts for majority of the metallisation processes for silicon wafer solar cells. Contact formation by co-firing of front and rear screen printed metal pastes for mainstream p-type standard solar cells is a well-established process. It is of utmost importance to use front and rear metallisation pastes that are co-firing compatible. In this paper, we describe a methodology for front and rear paste selection and process optimisation. We explore the usage of HF dip (20 seconds) on finished cells to differentiate between over-fired and under-fired contacts. Two commercially available front Ag pastes (paste 'A' & paste 'B') with fine line printing capability were tested along with two commercially available rear Al pastes (paste 'C & paste 'D'). Firing optimisation was conducted to achieve a one-Sun fill factor of 80.7 % and a series resistance at maximum power point (MPP) of 0.4 Ωcm2 at the optimised firing profile. The Al paste 'C, which resulted in a better and more uniform back surface field at the optimised profile, was selected to study the effect of post-metallisation HF etching. By choosing the correct combination of metal pastes, at the optimised firing profile, efficiencies of 18.5% were realised for standard screen-printed 156 mm × 156 mm p-type pseudo-square monocrystalline solar cells. © 2013 Published by Elsevier Ltd. Selection.
Shanmugam, V., Cunnusamy, J., Khanna, A., Boreland, M. B., & Mueller, T. (2013). Optimisation of screen-printed metallisation for industrial high-efficiency silicon wafer solar cells. In Energy Procedia (Vol. 33, pp. 64–69). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2013.05.040