Non-contact printed aluminum for metallization of Si photovoltaics

Aerosol jet printing is a contactless deposition technique that is ideally suited to depositing features on very thin and fragile substrates such as Si wafers. It can also be used to optimize device geometries including the Al back contact of a Si wafer solar cell quickly. A printable Al ink is required for this process, and we report lines and solar cells prepared with such a material. The resistivities of the printed Al lines approach bulk after appropriate sintering. Al lines printed on Si wafers have been heated over a wide temperature range of 550 to 800 °C to form low resistance contacts suitable for current extraction. Aerosol jet printed Al contacts to industrially produced 21 cm2 polycrystalline Si solar cells performed on par with all screen printed contacts on similar cells. These promising results demonstrate the potential for non-contact printed Al to contribute to the fabrication of low-cost photovoltaic devices and modules.