Construction of multiple heterointerfaces in layered thermoelectric nanocoating to realize highly sensitive remote fire-warning

Organic thermoelectric materials demonstrate significant application potential for remote temperature monitoring during the fire incubation period and early fire-warning. Nevertheless, their low thermoelectric efficiency compromises the sensitivity, reliability and accuracy of sensing signal. Herein, heterogeneous thermoelectric nanowires (HTN) and thermoelectric graphene (TEG) were synthesized, and they were subsequently co-assembled to construct a thermoelectric nanocoating featuring multiple heterostructure and ordered layered structure. Thanks to the synergistic effect of the two structures, the thermoelectric-response temperature-sensing of the nanocoating demonstrated exceptional sensitivity, accuracy, and stability. The nanocoating swiftly triggered a fire-warning within 1.3 s upon exposure to flame, and even in the event of secondary burning, the fire-warning trigger time was only extended to 1.5 s. The output voltage of the nanocoating exhibited a precise and repeatable linear functional relationship (U = 0.0248 T-0.779) within the temperature range of 50–300 °C, enabling remote real-time temperature monitoring when integrated with a wireless signal transmitter. Moreover, the ordered layered structure endowed the nanocoating with excellent flame-retardancy, enabling it to self-extinguish during the flame-retardant tests. Thus, this thermoelectric nanocoating opened a new pathway for intelligent fire safety protection of flexible electrical materials.