Resonant Thermal Emitters and PV Cells for Thermophotovoltaic Power Generation

• Published in: IEEE journal of photovoltaics Vol. 13; no. 5; pp. 716 - 727
• Main Authors: Choi, Kwong-Kit, Omair, Zunaid, Oduor, Patrick, Dutta, Achyut K.
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.09.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Absorptivity; Directional thermal emitters; electromagnetic modeling; Emission; Emitters; Energy conversion efficiency; Far fields; Kirchhoff law; Metals; near-field thermophotovoltaic (TPV); Optical device fabrication; Optical resonators; Photovoltaic cells; resonant photodiodes; resonator; Semiconductor materials; Silicon carbide; Stimulated emission; Surface waves; Three dimensional models
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2023.3282895

A thermophotovoltaic (TPV) power generation system based on resonator-pixel (RP) emitters and photovoltaic (PV) cells is proposed. The RP structure enables wavelength-selective emission and absorption, which increases the system power throughout and efficiency. An RP structure contains a thin semiconductor material etched into an array of micron-sized rings and covered with a metal layer. The emissivity of the RP emitter is determined by equating it to absorptivity and is modeled by three-dimensional electromagnetic modeling. The result shows that the emitter is able to increase the wavelength selectivity by eight times compared to a bulk emitter. Integrated with an RP PV cell having enhanced absorption at the band edge, the power conversion efficiency can be maintained constant in a wide range of temperatures, while the power throughput increases by 1.7 times. In addition, the RP emission is highly directional. Its far-field beamwidth is less than 10°, with which the emitter and PV cell can be placed at a larger distance to avoid convectional heating on the PV cell. In this work, we also confirm a near-field TPV effect that raises the electrical power by a factor of 2 when the emitter and cell are placed less than 2 μ m apart.