Thermal Desorption-Driven Temperature Sensor with Unprecedented High Sensitivity

Temperature measurement is fundamental to diverse fields such as industrial production, biological systems, and healthcare. However, developing temperature sensors with both high sensitivity and long-term stability remains a persistent challenge. Here, we introduce a novel temperature-sensing mechanism based on the thermal desorption of molecules from the surface of hydrophilic nanodiamond (H-ND). By modifying nanodiamond surfaces to enhance hydrophilicity, conductive channels are formed through the absorption of water molecules. As temperature rises, water molecules desorb, leading to a reduction in these conductive channels and an increase in resistance and enabling precise temperature sensing. The H-ND sensor exhibits a high temperature coefficient of resistance (TCR) of 1595%/°C within the range of 70-100 °C. Remarkably, the addition of salts such as NaCl further enhances the TCR to 415000% /°C within the same temperature range, the highest TCR reported to date for temperature sensors. Furthermore, we developed a flexible H-ND sensor array with 6 × 6 sensing cells, capable of generating high-resolution temperature images. This work provides a novel sensing mechanism that significantly advances the development and application of highly sensitive temperature sensors.