Thermophotovoltaic efficiency of 40

• Published in: Nature (London) Vol. 604; no. 7905; pp. 287 - 291
• Main Authors: LaPotin, Alina, Schulte, Kevin L., Steiner, Myles A., Buznitsky, Kyle, Kelsall, Colin C., Friedman, Daniel J., Tervo, Eric J., France, Ryan M., Young, Michelle R., Rohskopf, Andrew, Verma, Shomik, Wang, Evelyn N., Henry, Asegun
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.04.2022; Nature Publishing Group
• Subjects: 639/4077/4072/4062; 639/4077/4079; 639/624/1075/524; Alternative energy; back surface reflector; BSR; Decarbonization; devices for energy harvesting; Efficiency; Electric power; Electric power generation; Electric power grids; Electricity; Electricity distribution; Emitters; Energy gap; ENERGY STORAGE; Fabrication; Heat; Heat sources; High temperature; Hot Temperature; Humanities and Social Sciences; Infrared Rays; Low temperature; multidisciplinary; OMVPE; Photovoltaic effect; Photovoltaics; Radiation; Reflectors; Renewable energy; Renewable resources; Science; Science (multidisciplinary); SOLAR ENERGY; solar energy and photovoltaic technology; TEGS; Temperature; Thermal energy; thermal energy grid storage; thermophotovoltaic; Thermophotovoltaics; TPV; Tungsten; Turbines; United States > US
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-022-04473-y

Thermophotovoltaics (TPVs) convert predominantly infrared wavelength light to electricity via the photovoltaic effect, and can enable approaches to energy storage 1 , 2 and conversion 3 – 9 that use higher temperature heat sources than the turbines that are ubiquitous in electricity production today. Since the first demonstration of 29% efficient TPVs (Fig. 1a ) using an integrated back surface reflector and a tungsten emitter at 2,000 °C (ref. 10 ), TPV fabrication and performance have improved 11 , 12 . However, despite predictions that TPV efficiencies can exceed 50% (refs. 11 , 13 , 14 ), the demonstrated efficiencies are still only as high as 32%, albeit at much lower temperatures below 1,300 °C (refs. 13 – 15 ). Here we report the fabrication and measurement of TPV cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high-bandgap tandem TPV cells. The TPV cells are two-junction devices comprising III–V materials with bandgaps between 1.0 and 1.4 eV that are optimized for emitter temperatures of 1,900–2,400 °C. The cells exploit the concept of band-edge spectral filtering to obtain high efficiency, using highly reflective back surface reflectors to reject unusable sub-bandgap radiation back to the emitter. A 1.4/1.2 eV device reached a maximum efficiency of (41.1 ± 1)% operating at a power density of 2.39 W cm –2 and an emitter temperature of 2,400 °C. A 1.2/1.0 eV device reached a maximum efficiency of (39.3 ± 1)% operating at a power density of 1.8 W cm –2 and an emitter temperature of 2,127 °C. These cells can be integrated into a TPV system for thermal energy grid storage to enable dispatchable renewable energy. This creates a pathway for thermal energy grid storage to reach sufficiently high efficiency and sufficiently low cost to enable decarbonization of the electricity grid. Two-junction TPV cells with efficiencies of more than 40% are reported, using an emitter with a temperature between 1,900 and 2,400 °C, for integration into a TPV system for thermal energy grid storage.