Water-Soluble GeO ₂ -Transferred Ultrathin PI/MnCo ₂ O ₄ /Ta ₂ O ₅ Heterostructures for High-Sensitivity Flexible Temperature Sensors with Extreme Stability

Despite advancements in flexible temperature sensors, achieving high sensitivity with robust stability remains a critical challenge. In this work, we present a 40 μm-thick ultrathin, flexible negative temperature coefficient (NTC) sensor based on PI/MnCo₂O₄/Ta₂O₅, fabricated via a water-soluble GeO₂ sacrificial layer transfer technique. The sensor exhibits exceptional performance, including a high temperature coefficient of resistance (TCR) of -4.1%/°C, outstanding mechanical durability (ΔR < 4% after 10,000 bending cycles), and remarkable thermal stability (ΔR < 1.5% under thermal shock). The B25/50 value remains stable at 3650-3750 K, confirming excellent compositional reliability. Demonstrations in robotic e-skin and real-time respiratory monitoring highlight its potential for next-generation wearable technologies. This work provides a scalable strategy for high-performance flexible sensors in extreme environments.