Enhanced Thermoelectric Performance of InSb by Regulating the Carrier Concentration Combined With Resonant Level Doping

InSb-based semiconductors are promising candidates for medium-temperature thermoelectric applications owing to their non-toxicity, abundance, ultrahigh mobility, excellent process compatibility, and chemical stability. However, their single conduction band, small effective mass, and narrow optimal carrier transport range pose challenges for electrical property optimization. Herein, we achieve an obvious performance enhancement in InSb via Sn-doping, which concurrently induces resonant levels near the Fermi level and optimizes carrier concentration. This dual effect improves electrical conductivity while preserving a relatively high Seebeck coefficient, thereby yielding a remarkable power factor (PF∼5.60 mW m^-1 K^-2) in Sn-doped InSb. Ultimately, a high zT value of 0.80 at 723 K for InSn_0.00125Sb is achieved due to the enhanced power factor and reduced thermal conductivity, which is approximately 67% higher than that of intrinsic InSb. Furthermore, the corresponding single pair InSb-based module generates an open-circuit voltage of 94 mV and an output power of 2885 µW under a temperature difference of 320 K. In addition, an InSb-based solar-thermoelectric device using carbon nanotubes as the light absorption layer also demonstrates outstanding performance, highlighting its significant potential for applications in thermoelectric energy conversion.