Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States.
ACS Appl Mater Interfaces. 2013 Oct 9;5(19):9522-7. doi: 10.1021/am402200n. Epub 2013 Sep 26.
Thermally assisted transfer printing was employed to pattern thin films of high capacitance ion gels on polyimide, poly(ethylene terephthalate), and SiO2 substrates. The ion gels consisted of 20 wt % block copolymer poly(styrene-b-ethylene oxide-b-styrene and 80 wt % ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)amide. Patterning resolution was on the order of 10 μm. Importantly, ion gels containing the block polymer with short PS end blocks (3.4 kg/mol) could be transfer-printed because of thermoreversible gelation that enabled intimate gel-substrate contact at 100 °C, while gels with long PS blocks (11 kg/mol) were not printable at the same temperature due to poor wetting contact between the gel and substrates. By using printed ion gels as high-capacitance gate insulators, electrolyte-gated thin-film transistors were fabricated that operated at low voltages (<1 V) with high on/off current ratios (∼10(5)). Statistical analysis of carrier mobility, turn-on voltage, and on/off ratio for an array of printed transistors demonstrated the excellent reproducibility of the printing technique. The results show that transfer printing is an attractive route to pattern high-capacitance ion gels for flexible thin-film devices.
热辅助转印技术被用于在聚酰亚胺、聚对苯二甲酸乙二醇酯和 SiO2 基底上图案化具有高电容的离子凝胶薄膜。离子凝胶由 20wt%嵌段共聚物聚苯乙烯-b-聚环氧乙烷-b-聚苯乙烯和 80wt%离子液体 1-乙基-3-甲基咪唑双（三氟甲基磺酰基）酰胺组成。图案化分辨率在 10μm 左右。重要的是，由于热可逆凝胶化，含有短 PS 端基块聚合物（3.4kg/mol）的离子凝胶可以进行转印，这使得在 100°C 时凝胶与基底能够紧密接触，而具有长 PS 块（11kg/mol）的凝胶则由于凝胶与基底之间的润湿性接触不良而无法在相同温度下进行打印。通过使用印刷的离子凝胶作为高电容栅极电介质，制造了电解质门控的薄膜晶体管，其在低电压（<1V）下工作，并具有高导通/关断电流比（约 10(5)）。对印刷晶体管阵列的载流子迁移率、开启电压和导通/关断比进行统计分析，证明了该印刷技术具有极好的重现性。结果表明，转印是一种有吸引力的图案化高电容离子凝胶的方法，可用于柔性薄膜器件。
