Cellulose-Based Ionogels for Paper Electronics

• Published in: Advanced functional materials Vol. 24; no. 5; pp. 625 - 634
• Main Authors: Thiemann, Stefan, Sachnov, Swetlana J., Pettersson, Fredrik, Bollström, Roger, Österbacka, Ronald, Wasserscheid, Peter, Zaumseil, Jana
• Format: Journal Article
• Language: English
• Published: Hoboken Blackwell Publishing Ltd 01.02.2014; Wiley Subscription Services, Inc
• Subjects: Bend radius; Capacitance; Cellulose; Colloiding; electrolyte gating; Electrolytes; Electronics; Field effect transistors; Flexible components; flexible electronics; Ionic liquids; ionogels; Materials science; Multilayers; Nanorods; Substrates; Thin films; Zinc oxide
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201302026

A new class of biofriendly ionogels produced by gelation of microcellulose thin films with tailored 1‐ethyl‐3‐methylimidazolium methylphosphonate ionic liquids are demonstrated. The cellulose ionogels show promising properties for application in flexible electronics, such as transparency, flexibility, transferability, and high specific capacitances of 5 to 15 μF cm−2. They can be laminated onto any substrate such as multilayer‐coated paper and act as high capacitance dielectrics for inorganic (spray‐coated ZnO and colloidal ZnO nanorods) and organic (poly[3‐hexylthiophene], P3HT) electrolyte‐gated field‐effect transistors (FETs), that operate at very low voltages (<2 V). Field‐effect mobilities in ionogel‐gated spray‐coated ZnO FETs reach 75 cm2 V−1 s−1 and a typical increase of mobility with decreasing specific capacitance of the ionogel is observed. Solution‐processed, colloidal ZnO nanorods and laminated cellulose ionogels enable the fabrication of the first electrolyte‐gated, flexible circuits on paper, which operate at bending radii down to 1.1 mm. Highly flexible and biofriendly ionogels are produced by gelation of microcellulose thin films with 1‐ethyl‐3‐methylimidazolium methylphosphonate ionic liquids. The obtained ionogels can be laminated onto any substrate such as paper and act as high capacitance dielectrics for electrolyte‐gated inorganic (ZnO) and organic (P3HT) field‐effect transistors. They operate at very low voltages (<2 V) and enable the fabrication of flexible circuits on multilayer‐coated paper.