Maskless Fabrication of Highly Robust, Flexible Transparent Cu Conductor by Random Crack Network Assisted Cu Nanoparticle Patterning and Laser Sintering

A novel maskless fabrication method for highly flexible Cu random network transparent conductor has been developed by random nanocrack generation and subsequent Cu nanoparticle ink filling, transfer, and oxidation-free laser sintering without the aid of conventional photolithography or vacuum metal deposition steps. Use of random nanocrack on a silicon as a transfer printing template enables large area, high resolution network patterning, and fabrication in a simple maskless manner. At the same time, the laser sintering process allows low temperature, fast processing time, and oxidation suppression of Cu nanoparticle under ambient atmosphere. The fabricated Cu metal network establishes strong adhesion to plastic substrates, thus mechanical stability against tensile and compressive bending is attainable. Moreover, the template-assisted Cu metal network fabrication method minimizes waste of Cu nanoparticle as compared with other methods. A simple touch screen using Cu metal network-based transparent conductor is also demonstrated.