High-stability and skin-conformable temperature sensors based on all-solution-processed SnO₂@Ag core-shell nanowires

Ultra-stable, transparent, skin-conformable SnO₂@Ag NWs temperature sensors. • Sensors show a working range (30–130°C) and high sensitivity (TCR=0.31%°C⁻¹). • Excellent stability under chemical corrosion, 300 thermal cycles, and 3000 bends. • Sensors exhibit rapid response (1.5 s) and recovery (1.2 s). • Applied for monitoring human skin temperature and respiratory status. Skin-conformable temperature sensors with high stability and sensitivity are essential for electronic skin and real-time health monitoring. However, achieving high stability while preserving sensitivity and a broad linear working range remains a challenge. Herein, we report a novel, highly stable resistive temperature sensor based on an all-solution-processed SnO₂@Ag core-shell nanowire composite, embedded in an ultrathin polyvinylidene fluoride (PVDF) substrate (~5.1 μm) via laser direct writing. The conformal SnO₂ shell (~2 nm) protects Ag NWs from degradation without compromising conductivity and transparency. The resulting sensor exhibits high optical transparency (89.5% at 550 nm), a linear temperature sensing range of 30–130 °C, a temperature coefficient of resistance (TCR) of 0.31% °C⁻¹ , and a temperature resolution of 0.5 °C. Notably, the sensor demonstrates stable resistance after 300 thermal cycles (30–80 °C) and 3000 bending cycles, with a maximum hysteresis error of 1.73% over the full range, highlighting its mechanical and thermal robustness. Furthermore, the core-shell structure imparts robust resistance to moisture, oxidants, and salt solutions, ensuring reliable operation in harsh environments. As a proof-of-concept, the sensor enables precise, skin-conformal measurement of human body temperature, and offers a rapid response/recovery time of 1.5 s/1.2 s for respiratory pattern monitoring, showing its significant potential for electronic skin applications. Download: Download high-res image (153KB) Download: Download full-size image