This Small Business Innovation Research (SBIR) Phase I project will develop printable nickel materials and the laser reduction-sintering process to produce high-resolution metal electrodes on flexible substrates. Screen printing or inkjet printing with conductive inks based on metal nanoparticles is an attractive low-cost technology for direct metallization for optoelectronic devices. Today?s conductive inks and pastes are primarily made of silver. However, silver is expensive and prone to price volatility, whereas the price pressure of end consumer products is ever increasing. Therefore, silver alternatives are being sought, but the main challenge in replacing silver by inexpensive metals, such as copper and nickel, is in avoiding their oxidation at ambient conditions. Our innovation solves this problem by combining air-stable nickel oxide nanoparticles and laser processing, where the laser light induces direct local photochemical reduction, agglomeration, and sintering. Additionally, by employing the laser direct-write patterning, non-conducting nickel oxide film can be converted into a patterned, conducting nickel electrode in one step, without relying on complex process tools. This project will commercialize this technology by demonstrating the as-printed conductivity of nickel comparable to that of silver, by rigorous understanding of the photochemistry, ink formulation and laser process optimization. The broader impact/commercial potential of this project is to foster and advance printed electronics, an emerging market with tremendous growth potential across various end-user industries. The commercialization of large-scale printed-electronics is contingent on the development of low-cost materials and processes for conductive electrodes in many different application areas, including smart packaging, radio-frequency identification tags, flexible displays, biosensors, photovoltaics, thin film batteries, and smart textiles. Conventional electronic systems are fabricated using photolithography, a complex, multi-step process that requires expensive facilities and generates large volumes of hazardous waste, which damage the environment. The advancement of nanotechnology can convert inexpensive and more naturally abundant metals such as nickel into a functional material that can outperform silver. The total market for silver inks and pastes exceeds $7 billion today. If successful, the products developed in this project can capture a large share of this market. Printable electronics is a disruptive technology that has a profound effect to the America?s manufacturing competitiveness. The proposed project can establish a key component of this technology that stems from the fundamental work and promising results obtained by the collaborating team of researchers in photochemistry and nanotechnology.
