Bandgaps of multi-junction solar cells potentially determined at the sun height of the culmination on the winter solstice

Araki, Kiyomichi; Lee, Kan‐Hua; Yamaguchi, Masafumi

doi:10.1016/j.solener.2017.05.094

Cited by 13 publications

(15 citation statements)

References 24 publications

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“…Equation (13) is widely used to estimate in a simple way cell temperature along year [33,34]. The current mismatching in multijunction solar cells improves the fill factor (FF) [35]. The current matching ratio (CMR) is obtained by Equation (14),…”

Section: Calculation Of Power Outputmentioning

confidence: 99%

Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions

et al. 2020

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Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird’s model has been used as a general spectral model. However, atmospheric parameters such as aerosol optical depth and precipitable water have a constant value in the model that only applies to clear days. In this study, atmospheric parameters were extracted using the Bird’s spectrum model from the measured global spectrum and the seasonal fluctuation of atmospheric parameters was examined. We propose an overcast spectrum model and calculate the all-weather solar spectrum from clear to overcast sky through linear combination. Three types of PV modules (fixed Si, two-axis tracking Si, and fixed InGaP/GaAs/InGaAs triple-junction solar cells) were installed at the University of Miyazaki. The estimated performance ratio (PR), which takes into account incident angle and spectral variations, was consistent with the measured PR. Finally, the energy yield of various PVs installed across Japan was successfully estimated.

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Section: Calculation Of Power Outputmentioning

confidence: 99%

Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions

et al. 2020

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“…The initial value for optimization calculation can be given by that of combination determined at the sun height of the culmination on the winter solstice [1 00]. The optimized bandgap given by this method was identified to be closed to the values given by the optimizing routine [100]. Considering that the target of this calculation is to identify the variation of the output performance influenced by the different climate and spectrum in other years (Figure 2), the difference between the initial value and optimized value was not crucial, namely, both had broad distributions [100], and difference between the initial value and optimized results were often invisible.…”

Section: Monte Carlo Simulation For Analyzing the Annual Performance mentioning

confidence: 99%

“…The optimized bandgap given by this method was identified to be closed to the values given by the optimizing routine [100]. Considering that the target of this calculation is to identify the variation of the output performance influenced by the different climate and spectrum in other years (Figure 2), the difference between the initial value and optimized value was not crucial, namely, both had broad distributions [100], and difference between the initial value and optimized results were often invisible. Therefore, for saving the computation time, the first step of the flow-chart in Figure 2 was optimized not by the annual dataset (365 days multiplied by the number of division of the time in the daytime) but by the representative sun height in the one of the culmination on the winter solstice.…”

Section: Monte Carlo Simulation For Analyzing the Annual Performance mentioning

confidence: 99%

“…The angular characteristics in the photon absorption were assumed to be Lambertian. The open-circuit voltage at 1 kW/m 2 irradiance of each junction was assumed to the bandgap voltage minus 0.3 V, namely, the best crystal quality in the current epitaxial growth conditions [100]. Figure 3 and Figure 4 summarizes the assumptions in the calculation of the efficiency potential of the solar cell.…”

Section: Modeling Multi-junction Solar Cells Affected By a Variety Ofmentioning

confidence: 99%

“…Figure 6. Comparison between the measured and modeled seasonal trend of the performance of the PV module using multi-junction solar cells [100]. Pereformance ratio can be calculated by the formula defined as PR = Yf / Yr, where PR is performance ratio, and Yf is the integrated energy yield of oneday, and Yr is nominal energy yield of one day calculated by the STC module efficiency and total insolation.…”

Section: Energy Predictionmentioning

confidence: 99%

See 2 more Smart Citations

Super-Multi-Junction Solar Cell, Device Configuration with the Potential of More Than 50 % of the Annual Energy Conversion Efficiency (Non-Concentration)

Araki¹,

Ota²,

Saiki³

et al. 2019

Preprint

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The highest efficiency solar cell won in the efficiency race does not always give the most excellent annual energy yield in the real world solar condition that the spectrum is ever-changing. The study of the radiative coupling of the concentrator solar cells implied that the efficiency could increase by the recycle of the radiative recombination generated by the surplus current in upper junction. Such configuration is called by a super-multi-junction cell. We expanded the model in the concentrator solar cell to non-concentrating installation. It was shown that this super-multi-junction cell configuration was found robust and can keep the maximum potential efficiency (50 % in realistic spectrum fluctuation) up to 10 junctions. The super-multi-junction cell is also robust in the bandgap engineering of each junction. Therefore, the future multi-junction may not be needed to tune the bandgap for matching the standard solar spectrum, as well as relying upon artificial technologies like ELO (Epitaxial lift-off), wafer-bonding, mechanical-stacking, and reverse-growth, but merely uses up-right and lattice-matching growth technologies. We have two challenging techniques; one is the optical cap layer that may be the directional photon coupling layer in the application of the photonics technologies, and another is the high-quality epitaxial growth with almost 100 % of the radiative efficiency.

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Impact of the atmospheric conditions to the bandgap engineering of multi-junction cells for optimization of the annual energy yield of CPV

Araki

Lee

Yamaguchi

2017

AIP Conference Proceedings

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Bandgaps of multi-junction solar cells potentially determined at the sun height of the culmination on the winter solstice

Cited by 13 publications

References 24 publications

Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions

Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions

Super-Multi-Junction Solar Cell, Device Configuration with the Potential of More Than 50 % of the Annual Energy Conversion Efficiency (Non-Concentration)

Impact of the atmospheric conditions to the bandgap engineering of multi-junction cells for optimization of the annual energy yield of CPV

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