Key Laboratory of Thermal Science and Power Engineering of Ministry of Education, Beijing Key Laboratory for CO2 Utilization and Reduction Technology, Tsinghua University, Beijing, 100084, China.
MIIT Key Laboratory of Thermal Control of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Sci Rep. 2017 Apr 21;7(1):1026. doi: 10.1038/s41598-017-01197-2.
We show theoretically that 2D rectangular gratings on the surface of GaSb can serve as an "anti-reflection" pattern for nano-gap thermophotovoltaic (TPV) devices, which significantly enhances near-field radiative flux from the emitter to a GaSb cell, thus improving output power and conversion efficiency. The system in this study is a 200-nm gap TPV power generation system with a planar infrared plasmonic emitter and GaSb cell. Rigorous coupled-wave analysis is used to calculate the spectral near-field radiative flux involving periodic structures. The simulation shows that when coupled with a near-infrared plasmonic bulk emitter, adding gratings on the GaSb cell surface results in strong spectral enhancement above the cell's bandgap and suppression for low-energy photon transmission, an effect that cannot be fully predicted by the effective medium theory. The resultant peak spectral heat flux is 2.8 times as high as the case without surface structures and the radiative transfer efficiency increased to 24.8% from the original 14.5% with the emitter temperature at 1800 K. The influence of the grating's geometry parameters on the enhancement and peak frequency is further discussed with rigorous calculation of the spatial distribution of thermal radiative transfer that provided insight into the physical mechanism.
我们从理论上表明，GaSb 表面上的二维矩形光栅可以作为纳米间隙热光伏（TPV）器件的“抗反射”图案，这显著增强了发射器到 GaSb 电池的近场辐射通量，从而提高了输出功率和转换效率。本研究中的系统是一个 200nm 间隙的 TPV 发电系统，具有平面红外等离子体发射器和 GaSb 电池。严格耦合波分析用于计算涉及周期性结构的光谱近场辐射通量。模拟表明，当与近红外等离子体体发射器耦合时，在 GaSb 电池表面添加光栅会导致电池带隙上方的光谱增强和低能量光子传输的抑制，这种效应不能完全用有效媒质理论来预测。与没有表面结构的情况相比，峰值光谱热通量增加了 2.8 倍，当发射器温度为 1800K 时，辐射传输效率从原来的 14.5%增加到 24.8%。进一步通过严格计算热辐射的空间分布，讨论了光栅几何参数对增强和峰值频率的影响，为深入了解物理机制提供了帮助。
