Air-Bridge Si Thermophotovoltaic Cell with High Photon Utilization
Air-Bridge Si Thermophotovoltaic Cell with High Photon Utilization
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DOI：
10.1021/acsenergylett.2c01075
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发表时间：
2022-06-27
影响因子：
22
通讯作者：
Forrest, Stephen R.
中科院分区：
文献类型：
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作者：
Lee, Byungjun;Lentz, Rebecca;Forrest, Stephen R.
热光伏（TPV）电池将从热表面发射的光子转换成电能。与太阳能电池不同，TPV电池可以放置在靠近热源的位置，允许低于带隙（即，带外（out-of-band，OOB）光子被发射器反射和再吸收。随着OOB光子的反射率接近1，TPV的光谱效率变得对电池的带隙和源温度越来越不敏感。在这里，我们采用空气桥结构与横向结硅TPV电池作为一种手段，增加OOB反射率，这允许在低热源温度下的有效操作，长期无法有效的硅TPV发电。该器件表现出98.0 +/- 0.1%的OOB反射率和至少6 cm x 6 cm的空气桥可扩展性。与具有Au背表面反射器（BSR）的器件相比，具有空气桥BSR的器件在1988 K的热源温度下表现出25%的功率转换效率的相对增加。用可扩展且相对低成本的Si制成的TPV电池的这种性能改进可以潜在地加速TPV系统在能量存储和发电系统中的广泛使用。
Thermophotovoltaic (TPV) cells convert photons emitted from hot surfaces into electrical power. Unlike solar cells, TPV cells can be placed in close proximity to the heat source, allowing below-bandgap (i.e., out-of-band, OOB) photons to be reflected and reabsorbed by the emitter. As the reflectance of OOB photons approaches unity, the spectral efficiency of the TPV becomes increasingly insensitive to the bandgap of the cell and the source temperature. Here, we employ air-bridge structures with a lateral junction Si TPV cell as a means of increasing OOB reflectivity, which allows for efficient operation at low thermal source temperatures that were long inaccessible to efficient Si TPV power generation. The devices exhibit an OOB reflectance of 98.0 +/- 0.1% and an air-bridge scalability to at least 6 cm x 6 cm. Compared to devices with a Au back surface reflector (BSR), devices featuring an air-bridge BSR exhibit a 25% relative increase in power conversion efficiency at a thermal source temperature of 1988 K. Such performance improvements in TPV cells made with scalable and relatively low-cost Si can potentially expedite the widespread use of TPV systems in both energy storage and generation systems.