A novel method to eliminate the measurement artifacts of external quantum efficiency of multi-junction solar cells caused by the shunt effect

Li, Jing Jing; Lim, S. H.; Zhang, Yong-Hang

doi:10.1117/12.912790

Cited by 11 publications

(4 citation statements)

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“…With increased complexities in design and architecture of these types of cells, the task of performing electrical characterization and spectral response (SR) measurements of the cells will also become more involved. Although there are well-established procedures for performing current-voltage (I-V) or spectral response measurements in MJSCs [9,10], it has been shown previously that certain factors such as low shunt resistance [11][12][13][14][15][16][17], low reverse breakdown voltage [10,18] or luminescence coupling [12,[19][20][21][22][23][24][25] can cause artifacts in the spectral response or the quantum efficiency (QE) of the device.…”

Section: Introductionmentioning

confidence: 99%

Spectral response measurements of multijunction solar cells with low shunt resistance and breakdown voltages

Babaro

West

Hamadani

2016

Energy Science & Engineering

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Spectral response measurements of germanium-based triple-junction solar cells were performed under a variety of light and voltage bias conditions. Two of the three junctions exhibited voltage and light bias dependent artifacts in their measured responses, complicating the true spectral response of these junctions. To obtain more insight into the observed phenomena, a set of current-voltage measurement combinations were also performed on the solar cells under identical illumination conditions, and the data were used in the context of a diode-based analytical model to calculate and predict the spectral response behavior of each junction as a function of voltage. The analysis revealed that both low shunt resistance and low breakdown voltages in two of the three junctions influenced the measured quantum efficiency of all three junctions. The data and the modeling suggest that combination of current-voltage measurements under various light bias sources can reveal important information about the spectral response behavior in multijunction solar cells.

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Section: Introductionmentioning

confidence: 99%

Spectral response measurements of multijunction solar cells with low shunt resistance and breakdown voltages

Babaro

West

Hamadani

2016

Energy Science & Engineering

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“…be investigated to further improve the accuracy of the eXlstmg QE system which is already installed with the low impedance accessory [4]. …”

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confidence: 99%

Scaling error of quantum efficiency measurements for heavily shunted cells in reliability research

TamizhMani

Bowden

2014

2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)

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In photovoltaic (PV) cell and module reliability and durability research, it is of great importance to acquire an accurate quantum efficiency (QE) data of shunted cells which may be obtained after certain accelerated stress tests such as potential induced degradation (PID). The challenge in measuring accurate quantum efficiency of shunted cells stems from the interplay between the poor shunt resistance and the inherent impedance imposed by the traditional QE test equipment. Unless this test equipment related impedance is very, very low, the scaling error of the measured QE would be significant. A new very low impedance method which minimizes, but not totally eliminates, those erroneous drops in the QE system has been utilized to address the scaling error of the QE data of solar cells that have very low shunt resistances. This paper presents the challenges in measuring accurate QE of heavily shunted cells without measurement artifacts and the QE results obtained with and without the newly utilized low input impedance method.

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“…Therefore, we empirically establish 1 x 10 cm as a practical upper limit for the doping level of the BC base to allow a correct EQE measurement of the Ge subcell in an MJSC, regardless of other effects that might affect the EQE measurement (shunt resistance or light coupling) [8,10]. For higher doping levels, a straightforward way to measure the EQE of the subcell will be via an isotype Ge subcell although special procedures as described in Refs [15,16] might be successful and will be explored in a future study.…”

Section: Effects Of a Low V| R Of The Ge Subcell On Its Eqe Measuremmentioning

confidence: 99%

“…In brief, these papers show that the EQE of a subcell is not only determined by its own properties but also by the electro-optical interactions with other subcells in the stack. Light and voltage bias (Vj,¡ aj ) conditions have been suggested to minimize or eliminate this artifact [8,14,15], and a procedure has been already established to obtain the real EQE out of a device with strong luminescent coupling [12,15,16].…”

Section: Introductionmentioning

confidence: 99%

Implications of low breakdown voltage of component subcells on external quantum efficiency measurements of multijunction solar cells

Barrigón

Espinet‐González

Contreras

et al. 2015

Progress in Photovoltaics

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The electrical and optical coupling between subcells in a multijunction solar cell affects its external quantum efficiency (EQE) measurement. In this study, we show how a low breakdown voltage of a component subcell impacts the EQE determination of a multijunction solar cell and demands the use of a finely adjusted external voltage bias. The optimum voltage bias for the EQE measurement of a Ge subcell in two different GalnP/GalnAs/Ge triple-junction solar cells is determined both by sweeping the external voltage bias and by tracing the I-V curve under the same light bias conditions applied during the EQE measurement. It is shown that the I-V curve gives rapid and valuable information about the adequate light and voltage bias needed, and also helps to detect problems associated with non-ideal I-V curves that might affect the EQE measurement. The results also show that, if a non-optimum voltage bias is applied, a measurement artifact can result. Only when the problems associated with a non-ideal I-V curve and/or a low breakdown voltage have been discarded, the measurement artifacts, if any, can be attributed to other effects such as luminescent coupling between subcells.

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A novel method to eliminate the measurement artifacts of external quantum efficiency of multi-junction solar cells caused by the shunt effect

Cited by 11 publications

References 0 publications

Spectral response measurements of multijunction solar cells with low shunt resistance and breakdown voltages

Spectral response measurements of multijunction solar cells with low shunt resistance and breakdown voltages

Scaling error of quantum efficiency measurements for heavily shunted cells in reliability research

Implications of low breakdown voltage of component subcells on external quantum efficiency measurements of multijunction solar cells

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