Influence of morphological uniformity on the signal-to-noise ratio of EHD-printed ultrathin silver electrodes for capacitive touch sensors

초록

In this study, we fabricated coplanar capacitive touch sensors using electrohydrodynamic (EHD) printing and systematically investigated the influence of electrode width, spacing, height, and roughness on sensing performance. Reducing electrode spacing enhanced electrostatic coupling, improving both capacitance change (ΔC) and signal-to-noise ratio (SNR). Electrode width exhibited an optimal value, beyond which increased baseline capacitance reduced sensitivity. Although ΔC increased with electrode height, SNR decreased at higher thickness due to morphology-induced noise amplification caused by multi-pass printing. Ultrathin (∼60 nm) electrodes with high morphological uniformity achieved a maximum SNR of 41.6 dB with optical transmittance exceeding 93%. These results reveal that capacitive sensing performance is governed not only by geometric scaling but also by morphology-controlled noise, providing practical design guidelines for transparent, high-performance touch sensors. © 2026 Korean Physical Society

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