Inkjet-Printed Xerogel Scaffolds Enabled Room-Temperature Fabrication of High-Quality Metal Electrodes for Flexible Electronics

摘要

Inkjet-printed metal electrodes with desirable morphologies and electricalproperties are indispensable cornerstones for printable and flexible electronics.However, methods to fabricate metal electrodes nowadays mostlyrequest the sintering of printed metal particles, which not only will easilydamage heat-sensitive plastic substrates, but also is difficult to achievea smooth, neat, and highly adhesive electrode structure. Herein, a roomtemperature,solution-processable copper (Cu) electrode is demonstrated toovercome the above issues. The key is to inkjet print a stable xerogel scaffoldwith high porosity, good uniformity, and smoothness for growing highqualityCu via electroless deposition. Xerogel-based Cu electrodes exhibit abi-layer architecture, consisting of an upper thin-film Cu (with an electricalconductivity of ≈1.2 × 10~7 S m~（?1）) and a bottom Cu-polymer interpenetratednetwork. The electrodes show an excellent uniformity, surface smoothness,high interfacial energy to the plastic substrates (690–970 mJ m~（?2）), and goodflexibility. Taking these merits, the electrodes can be patterned onto variousplastic substrates and fabricate all-solution-processed electronic devices suchas organic thin-film transistors and organic electrochemical transistors withstable electrical performance.