Sun Chemical is now offering a broad range of metallization solutions for both additive and subtractive processes as well as module materials for use in the crystalline silicon (c-Si), thin film, printed electronics and other emerging markets. Products being highlighted include a variety of silver tabbing and aluminum backside pastes such as ‘SunTronic’ Cellmet 437W Backside Aluminum paste and SunTronic Cellmet 451W Silver Tabbing Paste.
Solar cell manufacturers are continually searching for new ways to reduce the cost of solar cells in both additive and subtractive processes for metallization pastes, insulators, and resists.
One of the key products being featured includes SunTronic Cellmet Aluminum metal pastes which are formulated for screen printing processes. Cellmet 437 was developed for use as the back electrode on mono or multi-crystalline silicon solar cells. These low bow, green environmental and health hazard friendly aluminum pastes are specially designed to form p+ doped layer when fired on a p-doped silicon photovoltaic devices. This paste has been optimized to eliminate Al bead formation during the firing process and has been optimized to be co-fireable with Sun Chemical’s and others front side silver and back side silver metallization pastes.
Back-surface electrode on mono or multi-crystalline silicon solar cells.
Cellmet 437 is specially designed to fire through the back surface of the silicon solar cells 180-220 mm thick. When fired at ~ 780oC peak temperature it gives the low bow of ~1.0 mm for 200 ± 20 micron thick 6” wafer as well as excellent electrical properties. The paste viscosity (40 ± 10 Pa.S) (no shear rate figure was given) is said to be suitable for screen printing of the complete back metallization. The product is fritted using an environmentally friendly lead and cadmium free glass composition and can be fired over a broad range of conditions including co-fire process techniques with front contact silver inks.