Selenium-Intercalated Ti3C2Tx MXene Thermoelectric Films: Enhanced Seebeck Coefficient, Power Factor Optimization, and Flexible Module Demonstration at Near-Room Temperature

This study investigates selenium intercalation strategy for Ti3C2Tx MXene thermoelectric films to simultaneously enhance Seebeck coefficient and maintain electrical conductivity for near-room-temperature power factor optimization within the context of materials science and thermoelectric device engineering, an area of growing scientific importance given its implications for wearable body heat harvesting, IoT sensor self-powered modules, and flexible thermoelectric generator integration in smart textiles. Using electrochemical Se intercalation of Ti3C2Tx colloidal MXene, thin film deposition by filtration and drop-casting, Seebeck coefficient measurement (static method), 4-probe electrical conductivity, Hall effect carrier density, and 5-couple flexible module assembly and characterization, we examine selenium filling interlayer vacancies and donating electrons to Ti d-band while simultaneously scattering low-energy electrons preferentially, shifting Fermi level and increasing energy filtering effect that raises Seebeck coefficient without proportional conductivity loss in 12 Se-loading compositions (0, 1, 2, 4, 6, 8, 10, 12 wt% Se) with n=3 independent film preparations each, characterized at 293 K, 323 K, and 353 K; 5-couple flexible module tested on 10 K temperature gradient drawn from Pacific Materials Institute MXene synthesis and thin film deposition facilities with Linseis LSR-3 Seebeck measurement and custom 4-probe conductivity stage at 20-80 C. Results indicate that 6 wt% Se loading achieves optimal PF = 0.284 mW/m/K^2 (5.3x pristine MXene) with S = -42 uV/K (vs. -8 uV/K pristine) and sigma = 1,600 S/cm; 5-couple module generates 2.84 uW on 10 K gradient at 300 K (p < 0.001), with PF 5.3x improvement at 6 wt% Se; S -42 vs. -8 uV/K; 2.84 uW module output on 10 K as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to materials science and thermoelectric device engineering and carry actionable implications for the design of programs and policies targeting wearable body heat harvesting, IoT sensor self-powered modules, and flexible thermoelectric generator integration in smart textiles.