Procedures for evaluating multijunction concentrators

Emery, Keith; Meusel, M.; Beckert, R.; Dimroth, Frank; Bett, Andreas W.; Warta, Wilhelm

doi:10.1109/pvsc.2000.916085

Cited by 55 publications

(39 citation statements)

References 3 publications

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“…2 The efficiency of a lens-cell assembly reflects both the optical and cell efficiencies. No standard exists for the characterization of the performance of a collection of concentrator cells designed for use under optics that split the spectrum into two or more parts.…”

Section: Efficiency Measurement Methodsmentioning

confidence: 99%

Very high efficiency solar cell modules

Barnett

Kirkpatrick

Honsberg

et al. 2008

Progress in Photovoltaics

185

102

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The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system-PV modules for portable applications that operate at greater than 50% efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical design, and the integration of these designs. Optical systems efficiency with an optical efficiency of 93% and solar cell device results under ideal dichroic splitting optics summing to 42Á7 W 2Á5% are described.

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Section: Efficiency Measurement Methodsmentioning

confidence: 99%

Very high efficiency solar cell modules

Barnett

Kirkpatrick

Honsberg

et al. 2008

Progress in Photovoltaics

185

102

View full text Add to dashboard Cite

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“…I Load I pT I dT I pM I dM I pB I dB (6) The diode (or dark) currents are the familiar Shockley ideal diode equation [10]:…”

Section: Measurement Analysismentioning

confidence: 99%

“…The flash voltage was selected to balance the top and middle subcell photocurrents, whereas the 0.7-eV bottom subcell photocurrent was neglected [6,11]. Thus, the Xe emission lines below the GaAs band edge at 900 nm were assumed to not adversely affect results.…”

Section: Triple-band-gap Cell Efficiency Measurementsmentioning

confidence: 99%

“…It has been realized for many years that accurate efficiency measurements of series-connected multijunction solar cells requires the incident spectral irradiance be such that the photocurrents of the component subcells correspond to those that would be produced by the reference spectrum [1][2][3][4][5][6]. Spectral content affects not only the short-circuit current (I sc ) but also the open-circuit voltage (V oc ), fill factor (FF), and maximum power point (P max ) of these devices.…”

Section: Introductionmentioning

confidence: 99%

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Concentrator cell efficiency measurement errors caused by unfiltered xenon flash solar simulators

Osterwald

Wanlass²,

Moriarty

et al. 2014

AIP Conference Proceedings

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“…The characterization of multijunction solar cells is complex and the interpretation of results is usually not straightforward. There are techniques available, e.g., quantum efficiency and spectral response, 3 current-voltage characteristics under illumination and calibration routines thereof, 4 and electroluminescence. However, all these techniques require complete cell structures, including metallization and encapsulation of individual devices.…”

mentioning

confidence: 99%

Photoreflectance analysis of a GaInP/GaInAs/Ge multijunction solar cell

Cánovas

Marrón

Martı́

et al. 2010

Applied Physics Letters

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We have analyzed the photoreflectance spectra of a GalnP/GalnAs/Ge triple junction solar cell. The spectra reveal signatures from the window layer and middle and top subcells included in the stack. Additional contributions from the multilayer buffer introduced between the mismatched bottom and middle cells have been detected. Franz-Keldysh oscillations (FKOs) dominate the spectra above the fundamental bandgaps of the GalnP and GalnAs absorbers. From the FKO analysis, we have estimated the dominant electric fields within each subcell. In light of these results, photoreflectance is proposed as a useful diagnostic tool for quality assessment of multijunction structures prior to completion of the device or at earlier stages during its processing.Multijunction solar cells currently represent the most efficient approach to photovoltaic energy conversión, with efficiencies over 40%. 1 ' 2 The multijunction design pursues the selective absorption of different parts of the solar spectrum by different absorbers in a layer stack so as to optimize the photogeneration and collection of minority carriers and to reduce energy losses related to thermalization of hot carriers. The characterization of multijunction solar cells is complex and the interpretation of results is usually not straightforward. There are techniques available, e.g., quantum efficiency and spectral response, 3 current-voltage characteristics under illumination and calibration routines thereof, 4 and electroluminescence. However, all these techniques require complete cell structures, including metallization and encapsulation of individual devices. It would be of a great interest to expand the diagnostic tools that reveal the optoelectronic quality of the subcells to earlier stages of device completion or even during processing of the multilayer stack. In this letter, the results of photoreflectance (PR) characterization of a triple junction structure without metallization are presented, and the suitability of PR to this aim is demonstrated. The solar cell structure was grown as an epitaxial, latticemismatched (metamorphic) structure by metalorganic vaporphase epitaxy (MOVPE). More details on the MOVPE growth process can be found elsewhere. 1

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Procedures for evaluating multijunction concentrators

Cited by 55 publications

References 3 publications

Very high efficiency solar cell modules

Very high efficiency solar cell modules

Concentrator cell efficiency measurement errors caused by unfiltered xenon flash solar simulators

Photoreflectance analysis of a GaInP/GaInAs/Ge multijunction solar cell

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