Determination of subcell I–V characteristics of multijunction solar cells using optical coupling

Nesswetter, Helmut; Jost, Norman; Lugli, Paolo; Bett, Andreas W.; Zimmermann, C.

doi:10.1002/pip.2722

Cited by 8 publications

(3 citation statements)

References 32 publications

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“…33,34 Note that a larger subcell shunt resistance in smaller-sized devices may cause a higher influence to voltage measurements: the device size of the concentrator solar cells used here is around three orders of magnitude smaller than that of solar cells used in previous studies. [33][34][35][36] Figure 8(a) shows the transient V oc under 1-ms pulsed illumination in the reference device with high shunt resistance J4 obtained for measurement-device resistance of 2 and 0.2 MΩ. For the reference device, a significant difference appears between measurements with different measurementdevice resistances.…”

Section: Discussionmentioning

confidence: 99%

“…32 As another approach, transient voltage measurements using pulsed light irradiation have been demonstrated to allow for the evaluation of the internal voltages of individual subcells. [33][34][35][36] The method is beneficial as the evaluation of the subcell voltage is not based on luminescence intensity, which makes the method potentially useful to study the luminescent effect. This method can be used to obtain the voltage in the subcell which is emitting luminescence, and it can be combined with LC current measurements to determine the fundamental LC properties to understand both the voltage-independent PL and the voltage-dependent EL.…”

Section: Introductionmentioning

confidence: 99%

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Transient analysis of luminescent coupling effects in multi-junction solar cells

Tayagaki

Reichmuth

Helmers

et al. 2018

Journal of Applied Physics

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We investigate the luminescent coupling (LC) effects in a four-junction GaInP/GaAs//GaInAsP/ GaInAs concentrator solar cell based on transient open-circuit voltage (V oc ) measurements under monochromatic illumination. Photocurrent generation in the non-absorbing GaInAs bottom subcell due to LC from upper subcells shows superlinear behavior with increasing light intensity. Along with this, a V oc enhancement is observed and quantified for illumination intensities that span almost six orders of magnitude. The V oc increase is explained and studied using a series-connected diode model including subcell shunt resistances, capacitances, and LC effects. The impact of unilluminated subcells on the subcell V oc determination is discussed for multi-junction solar cells. Finally, in the analysis of the LC generated photocurrent, namely, the coupling factor from the GaInAsP to the non-absorbing GaInAs subcell, a characteristic dependency on bias voltage is shown and explained by a result of competing photo-and electroluminescence mechanisms.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient analysis of luminescent coupling effects in multi-junction solar cells

Tayagaki

Reichmuth

Helmers

et al. 2018

Journal of Applied Physics

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“…[2] The band gap energy is an essential parameter to optimize the efficiency and the performance of III-V solar cells. However, in monolithic MJSC, the subcells are not accessible separately, which makes characterization and measurement procedures challenging [3], [4]. Traditional methods to measure the band gap energy of a semiconductor device include techniques based on absorption spectrum [5], ellipsometry [6], photoluminescence [7]- [10], electroluminescence [11], or spectral response [11], [12].…”

mentioning

confidence: 99%

Optical Characterization of III-V Multijunction Solar Cells for Temperature-Independent Band Gap Features

Baumgartner

Oksanen

Kärhä

et al. 2019

IEEE J. Photovoltaics

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A recently developed method to characterize the band gap energies of III-V optosemiconductors was utilized to determine temperature-invariant band gap features of multijunction solar cells. The method is based on measuring electroluminescent spectra of the solar cells at different temperatures. The normalized spectra reveal temperature-invariant energy values of the different junctions which are further converted to band gap energies. The method utilization requires a calibrated spectroradiometer and a temperature controlled mounting base for the solar cell under test, however, no knowledge about the absolute temperature of the cell under measurement. The method was tested on GaAs and GaInP solar cells that consist of single and dual junctions. The band gap energies were also derived from spectral response measurements. The differences of the determined band gap energies from the literature values were smaller than 1.1%. Compared with other band gap determination methods, the developed method yields temperature-invariant band gap characteristics; with a known uncertainty, that separated the different junctions in a multijunction device without individual biasing for the different junctions. In addition, a temperature-independent characterization parameter ensures that the operating conditions of the device under test do not affect the results. Index Terms-Band gap, light-emitting diode (LED), spectral response, temperature, III-V solar cells. I. INTRODUCTIONM ULTIJUNCTION solar cells (MJSC) based on III-V materials are the third generation of photovoltaic cells, to allow solar energy conversion with efficiencies as high as 46% [1]. In addition to the traditional space applications, recent studies have suggested new applications for high efficiency III-V solar cells in energy harvesting systems. Sensors and devices without batteries or wired power supplies in Internet of Things applications are often utilized in indoor conditions, where ambient light is nowadays produced by use of light emitting diodes Manuscript

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Using electroluminescence of subcells for obtaining fundamental resistive-less dark IV characteristic of multi-junction solar cells

Mintairov

Evstropov

Mintairov

et al. 2022

Solar Energy Materials and Solar Cells

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Determination of subcell I–V characteristics of multijunction solar cells using optical coupling

Cited by 8 publications

References 32 publications

Transient analysis of luminescent coupling effects in multi-junction solar cells

Transient analysis of luminescent coupling effects in multi-junction solar cells

Optical Characterization of III-V Multijunction Solar Cells for Temperature-Independent Band Gap Features

Using electroluminescence of subcells for obtaining fundamental resistive-less dark IV characteristic of multi-junction solar cells

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