Ferro Electronic Material Systems, a leading supplier of materials for fabricating photovoltaic silicon solar cells for more than 25 years, broadened its product line with the introduction of five new products at the 24th European Photovoltaic Solar Energy Conference and Exhibition held in Hamburg, Germany September 21-24. The products improve electrical output, efficiency, and manufacturability, enabling solar energy to become a more cost-competitive energy generation alternative.
Front Silver Pastes for Shallow Emitters
Products in this family, NS 33-510 and NS 33-520, yield greater power output, fire through silicon nitride anti-reflective coatings, and provide a broad processing window. They form excellent contact on 55-70 ohms/square high sheet resistivity emitters, and their rheology is suitable for high aspect ratio grid lines. The products are compatible with all Ferro rear silver pastes as well as lead-free and low-bow aluminum pastes. Both NS 33-510 and NS 33-520 are for use with emitters having a low surface concentration diffusion profile. They also are RoHS compliant and Cadmium-free.
In addition, NS 33-510 and NS 33-520 offer the advantages of Ferro's patented Hot Melt ink technology. This specially designed silver conductor system eliminates the drying process of conventional pastes, resulting in higher throughput rates, increased productivity, improved yields, and reduction of volatile organic compounds (VOCs). Solid at room temperature, Hot Melt pastes are resistively heated above their melting points to screen print similarly to conventional thick film pastes. Unlike conventional pastes, they instantly re-solidify when transferred to the solar cell surface and are ready for the next printing sequence. This unique property also improves the aspect ratio of printed grid lines and reduces shading, contributing to a higher cell efficiency than can be achieved with conventional screen printing materials. Fired line resolution of 80 microns wide x 30 microns thick has been achieved under optimal conditions.
Back Side Aluminum Paste
Ferro's AL 53-110 Series are lead- and cadmium-free aluminum conductors for the back surface of 180-220-µm thick silicon wafers. They exhibit less than 1.5 mm camber on 150 x 150-mm wafers at 180-µm thickness, enabling solar cell manufacturers to reduce silicon usage and costs. They eliminate aluminum bead formation during the firing process and can be fired over a broad range of conditions, including co-fire processes with front contact silver inks. AL 53-110 Series inks provide a shallow eutectic and a uniform back surface field (BSF) to yield a smooth surface and high electrical efficiency.
High Adhesion Rear Silver Pastes
PS 33-610 and PS 33-612 are cost-effective thrifted silver conductor pastes that provide high adhesion and excellent solderability when used with lead-free solders. Low interfacial resistance yields improved electrical performance. Both products are cadmium-free, and PS-610 is led-free. Both inks also offer the additional manufacturing benefits of Ferro's Hot Melt ink technology.