Rheologically-Tailored, High-Concentration Gold Nanoparticle Pastes for Advanced Deposition-Based Sensor Manufacturing

There is a growing demand for extreme miniaturization and enhanced sensitivity in the next-generation sensing systems, including wearable devices and bioelectronics. Such advanced platforms require highly conductive, biocompatible, and mechanically robust architectures capable of conforming to dynamic surfaces. Conventional metallic thin-film fabrication techniques have reached their fundamental physicochemical limits, often suffering from suboptimal mechanical strength, complex multi-step processing, and high costs. In contrast, additive manufacturing methodologies offer streamlined microfabrication, yet traditional printing methods frequently struggle with low-viscosity constraints, insufficient metal loading and significant material losses. Herein, the morphological fidelity, mechanical resilience, and electrical performance of the rheologically-tailored, high concentration (above 90%) gold nanoparticle paste deposited via the unique Ultra-Precise Dispensing (UPD) technology developed and continuously advanced by XTPL are assessed. The capability of the UPD system to print complex, high-density fractal geometries with linewidths down to 7 μm is evaluated on both rigid and flexible substrates, glass and polyimide, respectively. The mechanical structural integrity of these conductive traces is characterized under 360-degree bending tests. Finally, the electrical stability and thermal response of a printed proof-of-concept temperature sensor are evaluated. The printed fractal microstructures maintain excellent mechanical adhesion without cracking or delamination under severe strain, and the fabricated sensor demonstrates a highly stable, linear thermal response with a temperature coefficient of resistance of 1.98⋅10-3 oC-1, validating this combined material-deposition approach for microelectronics.