ScholarWorks@성균관대학교

초록

This study reports a photothermal–radiative cooling–coupled thermoelectric generator (TEG) that enables self-sustained electrical power generation under natural sunlight by establishing a system-level thermal configuration. The device consists of a W–MgF2 composite layer at the hot side and a paraffin-based composite containing SiO2, Al2O3, and BaTiO3 nanoparticles at the cold side, which operate cooperatively to maintain a stable temperature difference across the thermoelectric module. The W–MgF2 photothermal layer exhibits strong broadband solar absorption exceeding 75% up to 1500 nm and rapidly increases the hot-side temperature to approximately 67 °C under 1 sun illumination. In contrast, the paraffin-based composite suppresses heat accumulation at the cold side through selective mid-infrared emissivity together with enhanced thermal conductivity and thermal diffusivity, as supported by simulation results. As a result, a sustained temperature gradient of approximately 20 K is maintained across the device, leading to an output voltage of 5.7 mV under steady illumination. After electrical poling, the output voltage further increases to 6.2 mV without a noticeable change in the temperature gradient, indicating a polarization-assisted contribution from BaTiO3. Long-term operation confirms stable electrical output for more than 55 hr, demonstrating that the coupled photothermal heating and radiative cooling configuration effectively preserves the temperature gradient. Outdoor measurements, including operation in combination with a commercial aluminum heat sink, further confirm stable power generation and improved thermal management under practical operating conditions.

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