Ionogel/Copper\nGrid Composites for High-Performance,\nUltra-Stable Flexible Transparent Electrodes

Abstract

Production\nof high-performance and stable low-cost copper (Cu)-based flexible\ntransparent electrodes (FTEs) is urgently needed for the development\nof new-generation flexible optoelectronic devices, but it still remains\nchallenging. Herein, we developed a facile approach to fabricate high-performance,\nultra-stable Cu grid (CuG)-based FTEs by UV lithography-assisted electroless\ndeposition of patterned Cu on flexible polyethylene terephthalate\n(PET), which is then encapsulated by a thin poly­(1-vinyl-3-ethyl­imida­zolium\nbis­(trifluoro­methane­sulfonyl)­imide) (P­[VEIM]­[NTf₂]) ionogel layer to improve the mechanical flexibility and\nstability. The as-prepared composite FTE (ionogel/​CuG@​PET)\nexhibits a sheet resistance of 10.9 Ω sq^–1 and optical transmittance of 90% at 550 nm. Introduction of the\nthin uniform P­[VEIM]­[NTf₂] ionogel nanofilm by virtue\nof the superwettability of the Cu layer endows the electrode with\nexcellent mechanical flexibility and stability. This new high-performance\nCu-based FTE should be an attractive alternative to indium tin oxide\nfor practical optoelectrical applications.