Reducing optical losses in thermophotovoltaic systems

• Published in: Journal of power sources Vol. 501; p. 229972
• Main Authors: Khvostikov, V.P., Grachev, Ya.V., Vlasov, A.S., Khvostikova, O.A., Sorokina, S.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31-07-2021
• Subjects: Back surface reflector; Efficiency; Emitter; GaSb, photovoltaic converter; Thermophotovoltaic; GaSb, photovoltaic converter; Emitter; Thermophotovoltaic; Efficiency; Back surface reflector
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.229972

The reduction of optical losses in GaSb-based thermophotovoltaic converters via optimizing antireflection coatings and creating a back surface reflector on the photocell is reported. Upon the decrease in thickness of the GaSb substrate to 170 μm along with the lowering of its doping level to n ~2×1017 cm-3, the reflection coefficient of low-energy (λ < Eg) photons, R, is found to be ~ 0.7. A mathematical modeling at different temperatures and emitter materials shows that it is possible to increase the efficiency of thermophotovoltaic systems with tungsten and SiC emitters by 3% and 10.4% (at T = 1750 K), respectively, by using the back surface reflector with R ~ 0.7.
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•TPV system based on “black” emitter with unused radiation recirculation is a good alternative to those based on selective emitter.•“Black” emitter based TPV system is more compact and possesses efficiency higher than 20%.•Maximum reflection of 80% is reached on GaSb TPV cells with built-in back side mirror.•70% reflection can be achieved in practical systems with GaSb TPV cells.