GaSb booster cells for over 30% efficient solar-cell stacks

Fraas, Lewis M.; Girard, G. R.; Avery, James; Arau, B. A.; Sundaram, V. S.; Thompson, Amanda L.; Gee, J.M.

doi:10.1063/1.344051

Cited by 136 publications

(44 citation statements)

References 6 publications

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“…This was recognized by Boeing personnel, who had been investigating. GaSb cells in back of conventional GaAs cells, to produce a tandem solar cell which in their experiments yielded efficiencies up to 35%, significantly higher than plain GaAs cells [4]. The high efficiencies of the tandem cells derive from the spectral characteristics of GaSb, which enable it to utilize the wavelengths that pass through the GaAs cells.…”

Section: Introductionmentioning

confidence: 99%

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

Schock¹,

Mukunda²,

Or³

et al. 1994

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The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator (RTPV), to complement similar studies of Radioisotope Thermoelectric Generators (RTGs) and Stirling Generators (RSGs) previously published by the author. Instead of conducting a generic study, it was decided to focus the design effort by directing it at a specific illustrative space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a post-encounter cruise lasting up to one year.Because of Pluto's long distance from the sun (30-50 A.U.) and the mission's large energy demand, JPL has baselined the use of a radioisotope power system for the PFF spacecraft. RTGs have been tentatively selected, because they have been successfully flown on many space missions, and have demonstrated exceptional reliability and durability. The only reason for exploring the applicability of the far less mature RTPV systems is their potential for much higher conversion efficiencies, which would greatly reduce the mass, and cost of the required radioisotope heat source. Those attributes are particularly important for the PFF mission, which -like all NASA missions under current consideration -is severely mass-and cost-limited.The paper describes the design of an RTPV system consisting of a radioisotope heat source, a thermophotovoltaic converter, and an optimized heat rejection system; and depicts its integration with the PFF spacecraft. It then describes the thermal, electrical, and structural analysis which led to that optimized design, and compares the computed performance of an RTPV system to that of an RTG designed for the same mission. Our analytical results indicated thatwhen fully developed -it could result in a 60% reduction of the heat source's mass, cost, and fuel loading, a 50% reduction of generator mass, a tripling of the power system's specific power, and a quadrupling of its efficiency.The paper concludes by briefly summarizing the RTPV's current technology status and assessing its potential applicability for the PFF mission. For other power systems (e.g. RTGs), demonstrating their flight readiness for a long-term mission is a very time-consuming process. But for the case of the described RTPV design, the paper lists a number of factors, primarily its cold (0 to 10°C) converter temperature, that may greatly reduce the need for long-term tests to demonstrate generator lifetime. In any event, our analytical results suggest that the RTPV generator, when developed by DOE and/or NASA would be quite valuable not only for the Pluto mission but also for other future missions requiring small, long-lived, low-mass generators.

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Section: Introductionmentioning

confidence: 99%

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

Schock¹,

Mukunda²,

Or³

et al. 1994

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show abstract

“…But gallium antimonide (GaSb) or gallium-indium antimonide have spectral properties that make them attractive candidates for TPV applications. This was recognized by Boeing personnel, who had been investigating GaSb cells in back of conventional GaAs cells, to produce a tandem solar cell which in their experiments yielded efficiencies up to 35%, significantly higher than plain GaAs cells [4]. The high efficiencies of the tandem cells derive from the spectral characteristics of GaSb, which enable it to utilize the wavelengths that pass through the GaAs cells.…”

Section: Introductionmentioning

confidence: 99%

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Application to the Pluto Fast Flyby Mission

Schock¹,

Mukunda²,

Or³

et al. 1994

View full text Add to dashboard Cite

The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator. Instead of conducting a generic study, it was decided to focus the design effort by directing it at a specific space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a one-year post-encounter cruise.Because of Pluto's long distance from the sun (30-50 A.U.) and the mission's large energy demand, JPL has baselined the use of a radioisotope power system for the PFF spacecraft. The chief advantage of Radioisotope Thermophotovoltaic (RTPV) power systems over current Radioisotope Thermoelectric Generators (RTGs) is their much higher conversion efficiency, which greatly reduces the mass and cost of the required radioisotope heat source. Those attributes are particularly important for the PFF mission, which -like all NASA missions under current consideration -is severely mass-and cost-limited.The paper describes the design of the radioisotope heat source, the thermophotovoltaic converter, and the heat rejection system; and presents the results of the thermal, electrical, and structural analysis and the design optimization of the integrated RTPV system. It briefly summarizes the RTPV system's current technology status, and lists a number of factors that may greatly reduce the need for long-term tests to demonstrate generator lifetime. Our analytical results show very substantial performance improvements over an RTG designed for the same mission, and suggest that the RTPV generator, when developed by DOE and/or NASA would be quite valuable not only for the PFF mission but also for other future missions requiring small, long-lived, low-mass generators.

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“…A particularly key development was the adoption of a high-performance, low-band gap PV cell, made from Zndiffused gallium antimonide (GaSb) in the late 1980s and early 1990s [19,20]. Another key development in 1994 allowed STPV systems to reach sustained temperatures up to 1350 ∘ C [21].…”

Section: Introductionmentioning

confidence: 99%

Solar thermophotovoltaics: reshaping the solar spectrum

et al. 2016

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Abstract:Recently, there has been increasing interest in utilizing solar thermophotovoltaics (STPV) to convert sunlight into electricity, given their potential to exceed the Shockley-Queisser limit. Encouragingly, there have also been several recent demonstrations of improved systemlevel efficiency as high as 6.2%. In this work, we review prior work in the field, with particular emphasis on the role of several key principles in their experimental operation, performance, and reliability. In particular, for the problem of designing selective solar absorbers, we consider the trade-off between solar absorption and thermal losses, particularly radiative and convective mechanisms. For the selective thermal emitters, we consider the tradeoff between emission at critical wavelengths and parasitic losses. Then for the thermophotovoltaic (TPV) diodes, we consider the trade-off between increasing the potential short-circuit current, and maintaining a reasonable opencircuit voltage. This treatment parallels the historic development of the field, but also connects early insights with recent developments in adjacent fields. With these various components connecting in multiple ways, a system-level end-to-end modeling approach is necessary for a comprehensive understanding and appropriate improvement of STPV systems. This approach will ultimately allow researchers to design STPV systems capable of exceeding recently demonstrated efficiency values.

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GaSb booster cells for over 30% efficient solar-cell stacks

Cited by 136 publications

References 6 publications

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

Radioisotope Thermophotovoltaic (RTPV) Generator and Its Application to the Pluto Fast Flyby Mission

Solar thermophotovoltaics: reshaping the solar spectrum

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