MOF/MXene Nanocomposite to Improve Thermal Sensitivity and Bending Resistance of Flexible Temperature Sensor for Body Temperature and Respiration Rate Monitoring

Flexible thermal-resistance temperature sensors (RTSs) have caught tremendous attention due to their lightweight, good portability, fast response, and simple fabrication. However, it still remains an enormous challenge to construct a continuous and stable thermosensitive film with a high-temperature coefficient of resistance (TCR) compatible with flexible techniques. Here, we present a new way that loads the semiconductor metal-organic framework (MOF) Ni3 (HHTP)2 onto the 2-D conductive nanomaterial MXene via in situ polymerization in aqueous solution to fabricate the thermosensitive nanocomposite for the RTS. Due to the wide bandgap of the MOF (0.45 eV), the RTS exhibits a high thermal sensitivity (TCR) of −3.1% $\cdot ^{\circ }\text{C}\,\,^{\mathbf {-{1}}}$ . In addition, the RTS shows outstanding bending resistance over 1000 bending cycles because the MOF is anchored to the MXene tightly through coordination interaction, compensating for the weak bonding between the MOF particles. Besides, benefiting from the high electrical conductivity of MXene, the resistance of the MOF/MXene nanocomposite was reduced. The high sensitivity, excellent durability, high accuracy (0.1 °C), and fast response (1.2 s) enable the RTS to be applied in continuous body temperature and respiration rate monitoring. Therefore, we believe that the prepared RTS has promising application prospects in family medical systems and health surveillance.