The innovation engine for new materials

Sarah Schlossberg

Sarah Schlossberg


University of California San Diego


Chemical Engineering

Site Abroad: 

Leibniz Institute for New Materials, Saarbruecken, Germany


Johannes Maurer
Lola González-García

Faculty Sponsor(s): 

Tobias Kraus

Project Title: 

Large-area nanoprinting of ultrathin gold nanowires on flexible substrates

Project Description: 

Transparent, conductive materials (TCMs) are used in devices such as organic LEDs (OLEDs), solar cells, and touch screens. Many TCMs exhibit a tradeoff between transparency and conductivity: materials that are highly conductive tend to be opaque and those that are highly transparent tend to have a low conductivity. Currently, many commercial applications use ITO (indium tin oxide), which is brittle and requires high temperature sintering to make highly conductive films. It is not suitable for coating the polymer that form the basis of flexible TCMs. We developed an alternative based on metal nanostructures. Based on previous work on glass substrates, we built a conductive metal nanomesh on a polymer film. Ultrathin gold nanowires in dispersion were shaped into grids of various shapes (square, hexagonal, lines) using a pre-patterned polydimethylsiloxane (PDMS) stamp on a polyethylene terephthalate (PET) film. During printing, the wires followed the stamp geometry and self-assembled into bundles with submicrometer linewidth. The bundles were then sintered in a H2/Ar plasma to obtain a conductive and stable mesh. We achieved a high conductivity and a very high transmittance on PET. Mechanical tests confirmed the bending stability of our meshes. We can change the printing conditions to tune the conductivity and transparency of the coating. Transparent and flexible metal grids with high resolution and good stability can thus be produced as future TCMs.