A Metal-Quartz Composite Nozzle for Stable Electrohydrodynamic Jet Printing on Flexible Substrates

High-resolution patterning of organic polymer semiconductors is essential for the advancement of flexible optoelectronic devices. However, conventional techniques such as photolithography and inkjet printing suffer from limitations in resolution, substrate compatibility, and processing-induced damage. Here, we introduce a novel electrohydrodynamic jet (E-jet) printing approach employing a metal-quartz composite nozzle to realize the direct writing of uniform microwires on flexible substrates with micrometer-scale precision. The hybrid nozzle design mitigates the tendency of charge accumulation on insulating substrates, enabling stable jetting on insulating substrates. Numerical simulations were used to optimize the printing parameters, including applied voltage, printing height, and ink flow rate. Under optimal conditions, uniform microwire arrays of IDT-BT were successfully printed on PI substrates with a minimum width of 3 μm. Field-effect transistors (FETs) based on these printed microwires exhibited a hole mobility of 0.9 cm² V⁻¹ s⁻¹ and an on/off ratio of 0.6 × 10⁵. This work demonstrates a viable pathway for high-resolution, damage-free integration of semiconducting materials into consumer electronics.