Bandgap extraction from quantum efficiency spectra of Cu(In,Ga)Se2 solar cells with varied grading profile and diffusion length

Richter, Michael; Hammer, Maria S.; Sonnet, T; Parisi, J.

doi:10.1016/j.tsf.2016.08.022

Cited by 21 publications

(9 citation statements)

References 27 publications

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“…)) 2 method fails for graded absorbers (CIGS) as observed by Richter et al [3], and for devices with collection issues (here kesterite). Otherwise the values are in reasonable agreement with the optical measurements.…”

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confidence: 95%

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Bandgap of thin film solar cell absorbers: A comparison of various determination methods

et al. 2019

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Knowledge of the absorber bandgap is often needed for assessing the junction quality of a thin film solar cell, for example when computing the open-circuit voltage deficit. The bandgap is typically estimated from the routine measurement of the external quantum efficiency (EQE) of finished devices. However the extraction becomes ambiguous in the case of very thin absorbers, or in presence of bandgap gradients or collection issues of charge carriers. This work reviews several methods for the determination of the bandgap from EQE measurements and discusses their validity conditions. The numerical results are compared based on experimental EQE of several different thin film solar cells such as CuInGaSe 2 , CuInSe 2 , CdTe, CuZnSnSe and perovskite, and systematic trends are identified. Numerical simulations are also performed to illustrate the behavior of the different bandgap extraction methods in presence of a bandgap gradient and different magnitudes of the exponential tail states.

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confidence: 95%

“…However such approach fails for graded absorbers as reported in Ref. [3]. Variants and approximations of this expression are also commonly used.…”

Section: Introductionmentioning

confidence: 99%

Bandgap of thin film solar cell absorbers: A comparison of various determination methods

et al. 2019

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“…Figure 1 shows the quantum efficiency and photoluminescence of the devices. In order to extract the band gap energy from QE measurements, we employ the method described by Richter et al [24]. The internal quantum efficiency (IQE) is determined by the collection efficiency and the absorption characteristics of the solar cell.…”

Section: Effect Of Ordering and Annealing Time On The Band Gap Of Cu 2 Znsnsmentioning

confidence: 99%

Cadmium Free Cu₂ZnSnS₄ Solar Cells with 9.7% Efficiency

Larsen

Larsson

Törndahl

et al. 2019

Advanced Energy Materials

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“…As presented in ref. [25], for direct bandgap materials, the difference between the photons energy Eph and the bandgap Eg verifies:…”

Section: Results Analysismentioning

confidence: 87%

Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE

Onno

Tang

Oberbeck

et al. 2017

Journal of Crystal Growth

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Growth of high material quality Aluminum Gallium Arsenide (AlxGa1-xAs) is known to be challenging, in particular with an Al content x above 20%. As a result, the use of AlxGa1-xAs in devices requiring high minority carrier lifetimes, such as solar cells, has been limited. Nonetheless, it has long been established that the substrate temperature is a key parameter in improving AlxGa1-xAs material quality. In order to optimize the growth temperature of 1.70-eV Al0.22Ga0.78As solar cells, five samples have been grown by Solid-Source Molecular Beam Epitaxy (SSMBE) at 580°C, 600°C, 620°C, 640°C, and 660°C, respectively. A strong improvement in performance is observed with increasing the growth temperature from 580°C to 620°C. An open-circuit voltage above 1.21V has in particular been demonstrated on the sample grown at 620°C, translating into a bandgap-voltage offset Woc below 0.5V. Above 620°C, performances -in particular the short-circuit current density -moderately decrease. This trend is confirmed by photoluminescence, current density versus voltage characterization under illumination, and external quantum efficiency measurements.

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Bandgap extraction from quantum efficiency spectra of Cu(In,Ga)Se2 solar cells with varied grading profile and diffusion length

Cited by 21 publications

References 27 publications

Bandgap of thin film solar cell absorbers: A comparison of various determination methods

Bandgap of thin film solar cell absorbers: A comparison of various determination methods

Cadmium Free Cu₂ZnSnS₄ Solar Cells with 9.7% Efficiency

Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE

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Bandgap extraction from quantum efficiency spectra of Cu(In,Ga)Se2 solar cells with varied grading profile and diffusion length

Cited by 21 publications

References 27 publications

Bandgap of thin film solar cell absorbers: A comparison of various determination methods

Bandgap of thin film solar cell absorbers: A comparison of various determination methods

Cadmium Free Cu2ZnSnS4 Solar Cells with 9.7% Efficiency

Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE

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Cadmium Free Cu₂ZnSnS₄ Solar Cells with 9.7% Efficiency