Tailoring internal electric field to modulate carrier transport for enhanced thermoelectric performance in SWCNT for temperature monitoring

The high Seebeck coefficient ( S ) of inorganic semiconductors is expected to compensate for the low S of single-walled carbon nanotubes (SWCNT) with high electrical conductivity ( σ ). In this work, nano-Fe modified MoO 3 (Fe@MoO₃) has been synthesized by hydrothermal method. Then, high- S Fe@MoO 3 has been integrated with high- σ SWCNT for enhancing thermoelectric performance. The prepared Fe@MoO 3 /SWCNT exhibits an optimal power factor of 339.9 ± 16.7 μW m −1  K −2 with enhanced σ of 1125.7 ± 64.2 S cm −1 and the S of 55.0 μV K −1 , which is approximately three times that of the original SWCNT. The performance improvement is attributed to the nano-Fe in Fe@MoO 3 , which tailors the internal electric field of MoO 3 and compensates for electron capture from SWCNT through carrier mobility regulation, thereby effectively optimizing both σ and S . Furthermore, a thermoelectric module consisting of six pairs of p-type legs and copper wires is assembled, which demonstrates an optimal normalized power density of 2.42 μW cm −2  K −1 . For application demonstration, a temperature alarm device is built based on the thermoelectric module, which can be set to trigger alarms at different temperatures from 0 °C to 200 °C with a sensitivity of ±1 °C. Therefore, this work provides new insights into the preparation of SWCNT composites with enhanced thermoelectric performance.