Hybrid additive manufacturing of ultra-fine high-resolution shell–core structured conductive mesh-based flexible transparent electrodes for flexible displays

Metal mesh transparent electrodes present a promising alternative to Indium-Tin Oxide (ITO) due to their adjustable period and favourable trade-off between transmittance and conductivity. In this work, a template-free, non-high temperature hybrid additive manufacturing approach of the polyacrylonitrile (PAN)/Cu core–shell structure high-resolution metal mesh flexible transparent electrode (FTE) is proposed. The electric field-driven (EFD) 3D printing method was employed to print ultra-fine lines with widths as low as 1 μm. The composite-plating process combining electroless plating and electroplating has solved the structural defects of single deposition process. The prepared FTE has an excellent conductivity down to 1 Ω/sq and 89% light transmission (at 550 nm). Its exceptional mechanical properties and environmental stability make it suitable for diverse working environments. Even after undergoing 2000 bends at a radius of 3 mm, the resistance change rate remains as low as 1.4%. The resistance exhibits an approximately 8% change rate in the acid–base environment experiments conducted over 72 h. The flexible touch screen prepared with this FTE exhibits excellent writing performance in both flat and curved working scenarios. Furthermore, the significant potential of this FTE in the field of optoelectronics is effectively demonstrated through its exceptional luminescent performance in electroluminescent devices.