Carbon black-induced edge guided-metal lateral electrodeposition and its application in paper-based flexible electronic devices

The rapid advancement and development of flexible electronics are rendering traditional metal film preparation and patterning techniques increasingly inadequate to meet the processing requirements of diverse device forms. Herein, we proposed a novel copper film preparation and patterning method, named ‘‘edge guided-metal lateral electrodeposition’’ (EG-MLED), which was induced by a conductive carbon black (CCB) template. The key to this method lies in effectively suppressing the deposition of copper ions on the copper surface. By introducing the non-ionic surfactant polyethylene glycol (PEG) into the electroplating solution, the reduction potential of copper ions on CCB was effectively reduced because of the improved hydrophilicity of the CCB layer, while the reduction potential on copper was increased due to an increase in the resistance to electron transport at the solid–liquid interface. The newly formed copper layer served as the electron transport channel, facilitating the continuous deposition of copper ions along the edge of the developed copper layer. The deposition mechanism was studied in detail through controlled experiments, surface contact angle tests, in situ microscopy, and SEM. This EG-MLED method eliminated the reliance of traditional electroplating on conductive substrates and is especially suitable for preparing metal films on insulating substrates with complex surface structures. We successfully achieved copper film deposition on the surface of plastics, rubber, fibers, leather, wood blocks, and leaves, demonstrating the versatility and wide applicability of this method. The paper-based LED and photodetector devices prepared using this method demonstrate potential applications in the field of flexible electronics.