This Small Business Innovation Research (SBIR) Phase I project aims to develop nickel-based nanoinks for the front-side metallization of silicon solar cells. Current front-side metallization processes rely on screen printing contact methods that use silver paste, which contains glass frits that require high curing temperatures from 800 to 900 degree Celsius. The high temperatures introduce stress on the silicon wafer and the contact method risks cracking the wafer. In this project, nanonickel inks will be synthesized and deposited on solar panels by a non-contact Aerosol-Jet method at low temperatures from 300 to 400 degree Celsius. The nanonickel inks will be used as a seed layer for front-side metallization of solar panels. An additional layer of copper nanoinks will be deposited on top of the nickel layer creating thicker conductive lines.
The broader/commercial impact of this project will be the potential to offer a cost-effective replacement to silver paste for the front-side metallization of crystalline-silicon solar cells using a non-contact method. It is expected to provide manufacturing processes and materials that enhance quality of front-side metallization while reducing cost.
. Current commercial processes for front side metallization of silicon solar cells produce wide and thick contacts that cover 7 to 8% of the cell’s surface, thereby increasing shadowing and decreasing the efficiency of the cell. Current processes also rely on screen-printing contact methods that use silver paste, which contains glass frits that require high curing temperatures, 800 – 900 oC. The high temperature introduces stress on the silicon wafer and the contact method risks cracking the wafer. The objective of this proposal was to evaluate the feasibility of the synthesis of new materials, nickel nanoinks, which will be deposited on solar panels by a non-contact method and fired at low temperatures, 300 – 400 oC. These Phase I efforts proved technically feasible. A reliable and highly reproducible method for the production of nickel nanoparticles from inexpensive precursors was developed. A new approach for the scaling up reaction of high temperature synthesis was invented. The method produced high quality nickel nanoparticles with high yield. The obtained nanoparticles showed good printability and potential for using nanonickel as a seed layer for the front-side metallization of solar cells. Then an additional layer of copper nanoinks will be deposited on top of the nickel layer creating thicker conductive lines. The deposited inks will provide narrow lines that will increase the efficiency of solar cells and decrease the cost of solar cells metallization. Broader Impacts of the Proposed Activity The market for solar cells is dominated by silicon crystalline solar cells, and it accounts for more than 80% of the total PV market. Researchers and manufacturers are actively looking for processes or technologies to improve efficiency and to reduce the cost per watt of PV energy. The current process for the front side metallization of silicon cells includes a contact screen-printing method that produces wide lines, requires high firing temperatures and breaks silicon wafers. This Phase I project introduces the production of new materials for non-contact methods for the front-side metallization of solar cells. This approach will have a lasting impact on $1 billion market of silver pastes and inks for metallization of crystalline silicon solar cell industry by developing an inexpensive manufacturing process which improves efficiency, saves energy, enhances quality, decreases the cost of metallization and the amount of expensive materials needed. The public will benefit through a reduction in solar energy costs and the saving of precious metals including silver, and others with limited abundance. This research will also have a great impact on our understanding of material properties at small dimensions. This research will accelerate nanoparticles exploration and stimulate public and commercial interests in future nanotechnology. This Small Business Innovation Research Project Phase I will provide a basis for the large-scale manufacturing of nickel nanoinks in Phase II and beyond and at the same time will decrease the cost of manufacturing. These inks will serve as a new material for the front side metallization of solar cells due to improved quality and technological process.
