Nozzle heating with internal channel enhanced aerosol-jet printing with ultrahigh aspect ratio and ultrafine resolution for conformal electronics

Aerosol jet (AJ) printing enables conformal feature fabrication but struggles with limiting aspect ratio and resolution due to insufficient focus of aerosol ink particles. Here, we introduce an efficient method for AJ printing called nozzle heating with internal channel (NHIC), which incorporates a spiral flow channel into the nozzle, facilitating a continuous and temperature-controlled water bath through the channel to establish an auxiliary annular thermal field around the aerosolized ink particles (AIPs) flow, thereby modifying the flow field dynamics and enhancing the aerodynamic focusing of AIPs By raising up NHIC temperature to 90℃, a 7 μm wide deposited trace with a thickness of 2.1 μm was achieved. Above all, we increased the maximum aspect ratio of the printed deposits up to approximately 0.3, and improved the conductivity by 25 %. NHIC-enabled AJ printing successfully fabricated high-precision and high-density circuits, resistors, and conformal electrodes, demonstrating superior aspect ratio, resolution, thickness, and conductivity compared to conventional AJ methods for uneven conformal surfaces.