Dual-mode thermoelectric-thermochromic fiber with manipulated PEDOT:PSS-coated Te nanowires for early fire detection

Reliable and flexible early fire warning sensors play a crucial role in fire detection, yet remain a major challenge. Herein, we combined poly (p-phenylene benzobisoxazole) (PBO) nanofibers with thermoelectric and thermochromic (PTT) nano-functional particles to construct a dual-mode early fire warning sensing fiber, which realizes accurate temperature detection through visual and digital signal cooperative sensing. The resulting core-sheath structured nanoscale PTT sensing fiber features PBO nanofibers as sheath, with perovskite crystals assembled on the outermost layer, while the core is composed of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)@tellurium nanowires (Te NWs)/polyurethane composite thermoelectric nanomaterial. Incorporating PEDOT:PSS@Te NWs into the core facilitates a millisecond-level response to fire (threshold voltage: 1.0 mV, response time: ≤ 0.9 s) and wide temperature range (50–300 °C) fire warning performance. This rapid response is attributed to the optimization of the Te NWs nanointerface heterojunction structure, as well as the formation of a nanowire permeable conductive network, which synergistically enhances the Seebeck coefficient and conductivity ( S = 46.5 μV K − 1 , σ = 2.05 × 10 4 S m − 1 ). Moreover, the sensing fiber has achieved an independent power-free visual warning capability by utilizing colorimetric monitors and the thermochromic properties of perovskite crystals over a wide temperature range of 100–300 °C. This work offers a novel approach to develop a reliable real-time monitoring strategy with an impressive temperature sensing accuracy of up to 97.25% to early fire warning detection in precombustion.