Roll Printed and Roll Imprinted Flexible Transparent Conductive Films

J. Jo, K-Y Kim, Y-S Jang, P.W. Park
Korea Institute of Machinery and Materials(KIMM),
Korea

Keywords: roll print, roll imprint, flexible transparent conductive films

Summary:

In this paper, we report a method to fabricate low-resistance and high optical transparent conductive films (TCFs) using Ag metal grids and conductive polymer. First, a gravure-offset printing method was used to fabricate Ag electrode layers and a doctor blade coating method was also used to form thin polymer layers with a cell structure of substrate/ Ag grid/ PEDOT:PSS. The gravure-offset printing and soluble printing processes made it possible to fabricate printed TCFs with a line width of 5±0.5 μm on plastic substrates. The optical transparency and sheet resistance of Ag grid/ PEDOT:PSS were controlled in the range of 86 ~ 93 % and 1 ~ 10 Ω/□, respectively, by controlling the line width and pitch of Ag grid. Second, to conduct a simple fabrication process and produce a high resolution printed TCFs, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll-imprinted(TRI) patterned plastic substrates, patterned plastic substrates filled with high-conductivity and low-resistance Ag paste using a doctor blade coating, the Ag metal grid can be easily fabricated in a plastic substrates and coated with a thin film layer of conductive polymer by a spin coating process. The thermal roll-imprinting and soluble printing processes made it possible to fabricate printed TCFs with a line width of 10±0.5 μm, a channel length of 500±2 μm, and a pattern depth of 7.3±0.5 μm on plastic substrates. As a result of measuring line widths and channel lengths of a thermal roll-imprinted grid patterns, the linearity and uniformity characteristics for deviation and variation was good obtained. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of 1 ~ 9.6 Ω/□, transparent ratio was 83.6 ~ 91. 5% % at a wavelength of 550 nm.