STTR Phase I: Low Cost Copper Contacts with Built in Barriers for Crystalline Silicon Solar Cells

The broader impact/commercial potential of this Small Business Technology Transfer (STTR) Phase I project will be to lower manufacturing costs in the photovoltaic (PV) industry. In the past decade, the solar energy industry has seen double digit compound annual growth rates. This success has resulted in the industry consuming nearly 10 percent of the global silver production. The cost of metallization on silicon solar cells has become a notable cost driver for the manufacturers and the lack of stability of silver spot prices increases the volatility in this highly competitive industry. The successful implementation of copper inks would lead to significant cost savings, due to copper being around 100 times cheaper than silver. This project supports a materials research and development for a renewable energy industry that has the potential to offer significant cost savings to a very large industry. This Small Business Technology Transfer (STTR) Phase I project will develop copper based inks and pastes with an in-built diffusion barrier. The inks and pastes will be formulated from copper nanoparticles manufactured in solution phase. During this stage barrier layers will be grown directly upon the particles. This project will study the growth mechanisms of the nanoparticles and performance of the diffusion layer using high tech analysis techniques. The inks will be designed to be thermally processed using intense pulsed light (IPL) treatment, an advanced manufacturing technology. Reaction kinetics during IPL treatment will also be investigated in order to optimize ink formulations. This project will result in the formulation of two copper based inks for screen and ink jet printing, with optimized thermal processing conditions. Metal contacts formed with these inks will show that the barriers mitigate diffusion of copper into silicon and are a viable option for the replacement of the current silver contacts on silicon solar cells.