New back side silver paste from Heraeus offers savings for silicon PV cell fabricators

With superior coverage and adhesion properties that outperform existing products currently available, a new back side silver bus bar paste from the Thick Film Materials Business Unit of Heraeus offers a high-quality, cost-effective solution for solar cell manufacturers. The new Heraeus SOL230 paste is lead and cadmium-free and ideal for mono- and multi-crystalline silicon solar cells. SOL230 paste can be processed on textured and untextured wafers and allows the use of lead bearing and lead-free solder ribbons.

The increased adhesion of the paste enables a better solder joint, virtually eliminating the effects of humidity or contaminants that could cause thermal cycling or joint failure. The enhanced coverage properties of Heraeus SOL230 paste enables solar cell manufacturers to use less paste and save on material costs. The paste is co-firable with back aluminum and front silver pastes.

According to David Malanga, worldwide technical service manager for the Thick Film Materials Division of Heraeus, manufacturers could save more than $360,000 per year with the advantages provided by SOL230 over commercially available materials, assuming an $18.00 (USD) per troy ounce price for silver bullion and typical fabrication costs. He said if the current volatility of the silver market continues - and the price of silver surpasses $20 per troy ounce - the savings offered to fabricators using SOL230 could well exceed $360,000.

Malanga said SOL 230 paste and the other items in the HeraSol line of conductor pastes expands the company's product portfolio for solar cell applications, which also includes a complete line of sputtering targets and connector ribbons.

He also noted that dedicated personnel in Europe, Asia, and the US help Heraeus provide unmatched local technical and sales support for the photovoltaic industry.