Park et al. Nanoscale Research Letters 2012, 7:351 http://www.nanoscalereslett.com/content/7/1/351 N A N O E X P R E S S Open Access One-step fabrication of nanowire-grid polarizers using liquid-bridge-mediated nanotransfer molding Kyung S Park1, Jeong M Dang1, Myung M Sung1* and Soon-min Seo2 Abstract Ag nanowire-grid polarizers (NWGPs) were prepared by a one-step fabrication method, called liquid-bridge- mediated nanotransfer molding (LB-nTM). LB-nTM is a new direct nano-patterning method based on the direct transfer of various materials from a mold to a substrate via liquid layer. We fabricated NWGPs with Ag nanowire arrays (81 nm parallel lines and 119 nm spaces) on 2.5 in. transparent substrates by LB-nTM using an Ag nanoparticle solution. The maximum and minimum transmittances of the Ag NWGP at 800 nm were 80% and 10%, respectively. Keywords: Nanowire-grid polarizers, Direct printing method, Ag nanowire arrays PACS: 81.07.Gf Fabrication nanowires, 42.79.Ci optical polarizers, 81.20.Hy, molding Background Polarizer is an indispensable device in a wide range of optical systems, including flat panel displays, microdis- plays, and optical networking. Nanowire-grid polarizers (NWGPs) have been of great interest because of their excellent polarization performance and planar structure that allows them to be integrated to other thin-film optoelectronic devices. Moreover, they show good op- tical stability with respect to variation of the polar angle and azimuthal rotation, and excellent durability at high temperatures and under exposure to high UV flux [1]. The NWGP generally consists of fine grid of parallel metal nanowires with space and width less than the wavelength of light. For the light polarized parallel to the nanowire, it reflects, whereas for the light polarized perpendicular to the nanowire, it transmits. This type of polarizer shows very high extinction ratio between the reflected transverse electric-polarized light and the transmitted magnetic-polarized light over a wide wave- length range and incident angle. There are several fabrication methods for generating the NWGPs, which include photolithography [2], e-beam lith- ography [3-6], laser interference lithography [7,8], and * Correspondence: smm@hanyang.ac.kr 1Department of Chemistry, Hanyang University, Seoul 133-791, Korea Full list of author information is available at the end of the article nanoimprint lithography [9-17]. Among these techniques, nanoimprint lithography is a cost-effective and high- throughput method for the fabrication of metal nanowire grids over a large area, but it suffers from problems. For instance, it involves additional etching or sidewall depos- ition processes, and continuous fabrication can be difficult because vacuum conditions are required for metal depos- ition. Recently, we have developed a new direct printing method for generating nanometer-scale patterns of vari- ous materials, called liquid-bridge-mediated nanotransfer molding (LB-nTM) [18]. LB-nTM is based on the direct transfer of various materials from a mold to a substrate through a liquid bridge between them. This new tech- nique is capable of generating well-defined large-area nanowire patterns through one step and is well suited for use in automated direct printing machines. LB-nTM is the most efficient method for the fabrication of the wire-grid polarizers at low cost and low environmental impact. Here, we report the one-step fabrication of the nanowire- grid polarizer using LB-nTM with an ink solution. Figure 1 illustrates the procedure to produce the Ag NWGP by LB- nTM using an Ag nanoparticle solution. First, a patterned mold fabricated by polyurethane acrylate (PUA) is filled with an Ag nanoparticle solution using selective inking [19]. The filled ink is next solidified by drying at mild tempera- tures (<100 °C). Almost no particles remain on the © 2012 Park et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.