Nanoparticle Derived Contacts for Photovoltaic Cells

Contacts are becoming increasingly important as PV devices move to higher efficiency and lower cost. We present an approach to developing contacts using nanoparticle-based precursors. Both elemental, alloy and compound nanoparticles can be employed for contacts. Ink based approaches can be utilized at low temperatures and utilize direct write techniques such as ink jet and screen printing. Theability to control the composition of the nanoparticle allows improved control of the contact metallurgy and the potential for thermodynamically stable interfaces. Key is the ability to control the interface between particles and between particles and the substrate. We illustrate some of these principals with recent results on Al, Cu and (Hg,Cu)Te. We show for the elemental materials control ofthe surface can prevent oxide formation and act as glue to control the reactivity of the nanoparticles.