Light-Induced Plating of Screen-Printed Multi-Crystalline Silicon Solar Cells

Light-induced plating (LIP) has been used to evaluate solar cells screen-printed on 28 mm x 28 mm multi-crystalline Si (mc-Si) wafers from experimental silver thick-film pastes A and B. Cells were fabricated from paste A using screens with 60, 80, and 100 mu m wide line openings. After firing at optimal temperature and measuring electrical performance, the cells were plated using the LIP process. Cell fill factor and efficiency increased noticeably while cell series resistance decreased. The observed efficiency increase ranged from 0.4% to 1.0% and was due to improved contact resistivity and decreased conductor line resistance. The mechanism for improved performance was elucidated through conductivity measurements and microstructural investigation using advanced scanning electron microscopy. Surface morphology of the silver conductor line obtained from the LIP process is reported. Cells from paste B were printed with a 100 mu m wide opening screen. The efficiency of cells printed with paste B using the 100 mu m screen followed by the LIP process did not show an efficiency improvement. It is shown that an optimally designed, state-of-the-art paste (paste B) can deliver sufficiently low series resistance and achieve high cell efficiency without using the LIP process. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.021111jes] All rights reserved.