Thermophotovoltaic (TPV) systems are a promising technology for distributed conversion of high-temperature heat to electricity. To achieve high conversion efficiency, the transport of sub-bandgap radiation between the thermal emitter and PV cell should be suppressed. This can be achieved by recycling sub-bandgap radiation back to the emitter using a spectrally selective cell. However, conventional TPV cells exhibit limited sub-bandgap reflectance. Here we demonstrate thin-film In_0.53Ga_0.47As-based structures with high spectral selectivity, including record-high average sub-bandgap reflectance (96%). Selectivity is enabled by short optical paths through a high-quality material fabricated using epitaxial lift-off, high-reflectance back surfaces, and optimized interference. In addition, we use a parallel-plate TPV model to evaluate the impact of specific structural features on performance and to optimize the cell architecture. We show that a dielectric spacer between InGaAs and the Au back surface is an important feature that enables a predicted TPV efficiency above 50% (with a power output of 2.1 W/cm²), significantly higher than current TPV devices. This work provides guidelines for the design of high-efficiency, low-cost TPV generators.

中文翻译：

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热光电池具有高光谱选择性的薄膜架构

热光电（TPV）系统是一种将高温热量分布式转换为电的有前途的技术。为了获得高转换效率，应抑制热发射器与PV电池之间的子带隙辐射的传输。这可以通过使用光谱选择性电池将子带隙辐射循环回发射器来实现。然而，常规的TPV盒显示出有限的亚带隙反射率。在这里我们展示了薄膜In _0.53 Ga _0.47具有高光谱选择性的As基结构，包括创纪录的高平均子带隙反射率（96％）。通过使用外延剥离，高反射背表面和优化干涉而制造的高质量材料的短光路，可以实现选择性。此外，我们使用平行板TPV模型评估特定结构特征对性能的影响并优化单元架构。我们表明，InGaAs和Au背面之间的电介质隔离层是一项重要功能，可使预计的TPV效率高于50％（功率输出为2.1 W / cm ²），远高于当前的TPV器件。这项工作为设计高效，低成本的TPV发电机提供了指导。