15-Fold increase in solar thermoelectric generator performance through femtosecond-laser spectral engineering and thermal management
Tianshu Xu, Ran Wei, Subhash C. Singh, Chunlei Guo
Abstract
Solar thermoelectric generators (STEGs) have recently gained increasing attention. However, their widespread adoption has been limited due to the lack of high-efficiency thermoelectric materials and compact heat sinks for effective heat dissipation. To address these issues, we develop a spectral engineering and thermal management strategy that significantly increases STEG power generation by 15 times with only a 25% increase in weight. At the hot side, we transform a regular tungsten (W) to a selective solar absorber (W-SSA) through a femtosecond (fs)-laser processing technique, which enhances the solar absorption while minimizing the IR emissivity, obtaining >80% absorption efficiency at elevated temperatures. We also design a greenhouse chamber for W-SSA and achieved >40% reduction in convective heat loss. At the cold side, we apply the fs laser processing to transform a regular aluminum (Al) to a super-high-capacity micro-structured heat dissipator (μ-dissipator), which improves the cold-side heat dissipation through both radiation and convection, achieving twice the cooling performance of a regular Al heat dissipator. These spectral engineering and thermal management increase the temperature difference across the STEG, resulting in a substantial increase in output power. The high-efficiency STEG can find a wide range of applications, such as wireless sensor networks, wearable electronics, and medical sensors.