Metal mesh electrode array fabricated by plate-to-roll nanoimprint lithography

Abstract

Nanoimprint lithography has long been considered a way of fabricating micronano structures in a high-efficiency manner. Based on this method, various 2D and 3D structures with feature sizes ranging from a few micrometers down to a single nanometer have been demonstrated. Here, we present the mechanical and control system design of recently developed plate-to-roll nanoimprint equipment. To improve the parallelism between the template and the substrate, we propose a three voice coil motor actuated mechanical structure and improved proportion integration differentiation algorithm, which can provide fast response and precise positioning. We used a template with a grooved structure to test the embossing performance. By using the nanoimprint system, an electrode array based on a metal mesh transparent conductive material was fabricated on a flexible substrate, which shows the great potential of this system for the fabrication of flexible devices.

A Microcontact-Printed Nickel-Passivated Copper Grid Electrode for Perovskite Photovoltaics

“…Transparent conducting electrodes (TCEs) serve an indispensable role in a wide range of optoelectronic devices including photovoltaics (PVs), supercapacitors, smart windows, touch screens, and organic light-emitting diodes . Over the past decade a number of innovative approaches have been reported for the fabrication of TCEs based on a fine grid of opaque metal lines together with a high transparency, low conductivity layer that spans the gaps between them. − This approach to TCE design offers a path for achieving performance matched to the requirements for several potentially very low cost, emerging thin film PVs, including perovskite PVs: A sheet resistance much less than 10 Ohms per square and far-field transparency >80% for light wavelengths in the range 400–900 nm. − Metal mesh electrodes are particularly attractive for organic PVs and perovskite PVs, as a replacement for the transparent conducting oxides (TCOs) indium-tin oxide (ITO) and fluorine-doped tin oxide (FTO) currently used. This is because ITO uses the high cost element indium, and both of these oxides are inherently brittle which limits their performance on the flexible plastic substrates needed for low cost roll-to-roll device processing .…”

“…Methods for the fabrication of metal grid electrodes with very narrow line-width and small line spacing include nanoimprint lithography, cracked film lithography, and microcontact printing (μ-CP) . μ-CP is a lithographic method, invented by George M. Whitesides, that uses a patterned molecular etch resist <2 nm thick and can achieve feature sizes as small as 100 nm in copper (Cu), silver (Ag), gold (Au), and aluminum (Al) over large areas .…”