Enabling Highly Enhanced Solar Thermoelectric Generator Efficiency by a CuCrMnCoAlN-Based Spectrally Selective Absorber
Xi Liu, Peng Zhao, Cheng‐Yu He, Weiming Wang, Baohua Liu, Zhong‐Wei Lu, Yunfeng Wang, Huixia Guo, Gang Liu, Xiang‐Hu Gao
Abstract
Harvesting solar energy to enhance thermoelectric generator efficiency is a highly effective strategy. However, it is a grand challenge but essential to increase solar-thermal conversion efficiency. A spectrally selective absorber, which is capable of boosting solar absorptance (α) while suppressing thermal emittance (ε), shows great potential to elevate the solar-thermal conversion efficiency. Herein, we fabricate a multilayer spectrally selective absorber with the assistance of high-entropy nitrides, which shows outstanding spectral selectivity (α/ε = 95.2/10.9%). Benefitting from the high-entropy nitrides, it is experimentally demonstrated that the as-deposited absorber exhibits superior thermal stability, which is crucial to ensure service life. Under 1000 W·m–2 simulated solar illumination, it achieves a very high surface temperature of 109.6 °C, making it suitable to enhance the efficiency of solar thermoelectric generators. Impressively, the integration of the proposed absorber with a commercial thermoelectric generator efficiently reinforces thermoelectric performance, offering a high output power of 1.99 mW. More importantly, by taking advantage of a thermal concentration strategy, it enables a further increase of the output power by 2.98 mW. This work provides a promising solar-thermal material to boost high thermoelectric performance and extends the application category of high-entropy nitrides.