Optical methodology for process monitoring of chalcopyrite photovoltaic technologies: Application to low cost Cu(In,Ga)(S,Se)2 electrodeposition based processes

Oliva, Florian; Kretzschmar, Steffen; Colombara, Diego; Tombolato, Sara; Ruiz, Carmen M.; Redinger, Alex; Saucedo, Edgardo; Broussillou, C.; Monsabert, Thomas Goislard de; Unold, Thomas; Dale, Phillip J.; Izquierdo-Roca, Víctor; Pérez-Rodrı́guez, A.

doi:10.1016/j.solmat.2015.12.036

Cited by 51 publications

(46 citation statements)

References 55 publications

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“…The EL image acquired by the InGaAs camera (Figure a) is much more inhomogeneous than the image acquired by the silicon camera (Figure b). The EL image acquired by the InGaAs camera gives a better representation of the overall EL intensity than the Si camera because of its flat QE in the spectral range of the EL emission . The EL image acquired by the silicon camera may be misleading because the silicon camera acquires only the high energy part of the EL spectrum; therefore, the image tends to show higher EL intensity where the bandgap is higher, and not necessarily where the overall EL signal is higher.…”

Section: Discussionmentioning

confidence: 99%

Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence

Bokalič

Pieters

Gerber

et al. 2016

Prog. Photovolt: Res. Appl.

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A unique non‐destructive characterization method for apparent bandgap imaging in photovoltaic (PV) devices based on acquisition of two electroluminescence (EL) images in different spectral ranges is presented. The method consists of a calibration procedure and a bandgap imaging procedure. Calibration has to be performed once per module type and EL imaging setup, and must provide a relation between the bandgap and the ratio between two spectrally independent EL images. After calibration, bandgap imaging only requires acquisition of two spectrally independent EL images followed by image processing, making the method very fast and suitable for in‐line PV module characterization with regard to spatial (in)homogeneity and production process stability. The method is demonstrated on a commercial state‐of‐the‐art Cu(In,Ga)Se2 PV module where apparent bandgap fluctuations between 1.07 and 1.15 eV are detected. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence

Bokalič

Pieters

Gerber

et al. 2016

Prog. Photovolt: Res. Appl.

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“…The 785‐nm excitation wavelength was used for 2 reasons. The first one is due to the low interaction of this wavelength with the upper window layer that allows to characterize the absorber without removing the CdS/ZnO/ITO layers . The second advantage is related to the coupling of the energy of the excitation photons with the direct band gap of SnSe 2 .…”

Section: Methodsmentioning

confidence: 99%

“…The first one is due to the low interaction of this wavelength with the upper window layer that allows to characterize the absorber without removing the CdS/ZnO/ITO layers. 42 The second advantage is related to the coupling of the energy of the excitation photons with the direct band gap of SnSe 2 . This allows to work under resonant conditions largely increasing the sensitivity of the Raman measurements of this phase by several orders of magnitude.…”

Section: Characterizationmentioning

confidence: 99%

CZTSe solar cells developed on polymer substrates: Effects of low‐temperature processing

Becerril‐Romero

Acebo

Oliva

et al. 2017

Progress in Photovoltaics

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Cu2ZnSn(S1−xSex)4 solar cells are well suited for roll‐to‐roll mass production since they are formed mainly by non‐toxic and earth‐abundant elements. Polyimide (PI) has proved to be a promising roll‐to‐roll compatible substrate yielding very high efficiency devices for Cu(In,Ga)Se2. In this work, we demonstrate the feasibility of using PI as a low‐weight and flexible alternative to soda‐lime glass for Cu2ZnSnSe4 (CZTSe) solar cells. Two main concerns arise when working with PI. Firstly, its low thermal robustness limits process temperatures below 500°C. The second concern is the lack of alkali in PI in contrast to conventional soda‐lime glass fundamental for high efficiency devices. This work tackles both issues. First, different alkali doping strategies are investigated for the incorporation of Na and K into CZTSe absorbers prepared on PI substrates by sequential precursor sputtering and selenization at 470°C: pre‐absorber synthesis and post‐deposition treatment. Post‐deposition treatment does not lead to an improvement of performance. Pre‐absorber synthesis effectively dopes the CZTSe absorbers increasing the solar cell performance and carrier concentration of the devices. Cu2ZnSnSe4 devices are then fabricated on glass and PI at different temperatures (450°C‐490°C). A detrimental SnSe2 secondary phase is detected in most of these devices. The formation of this phase is proved to be strongly related to process temperature. Despite this, a 6.4% efficiency device is achieved at 490°C on glass. Finally, through further experimentation and the addition of a Ge nanolayer, we report a 4.9% efficiency flexible device on PI setting a new record for kesterite solar cells on a polymer substrate.

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“…Hyperspectral imaging techniques have the potential to provide information regarding the optoelectronic properties of materials and devices with spatial resolution (Unold and Gütay, 2016;Oliva et al, 2016). In contrast to conventional luminescence spectroscopy measurements where the emitted light is collected from a single spot, hyperspectral imaging luminescence offers the possibility to acquire spatially-resolved luminescence maps within a single measurement cycle where the whole sample is illuminated homogeneously.…”

Section: Optical Spectroscopymentioning

confidence: 99%

Advanced characterization and in-situ growth monitoring of Cu(In,Ga)Se2 thin films and solar cells

et al. 2018

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The continuous improvement of Cu(In,Ga)Se 2 (CIGSe) solar cells relies considerably on advanced characterization of individual layers in the solar-cell stacks as well as of completed CIGSe devices. The present contribution provides an overview of corresponding efforts performed by various research groups at Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. In-situ growth monitoring of CIGSe absorber layers by means of energy-dispersive X-ray spectrometry and light scattering is described, as well as structural analyses by means of X-ray and neutron diffraction. In addition, the characterization of surfaces and interfaces by soft X-ray and electron spectroscopy, the microscopic analysis by means of correlative electron microscopy, and optoelectronic characterization by optical spectroscopy are highlighted. The present contribution shows which substantial efforts in a research network are necessary in order to obtain deeper insight into materials properties and potentially limiting factors for the device performance, as well as to be able to control these factors during the solar-cell production.

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Optical methodology for process monitoring of chalcopyrite photovoltaic technologies: Application to low cost Cu(In,Ga)(S,Se)2 electrodeposition based processes

Cited by 51 publications

References 55 publications

Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence

Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence

CZTSe solar cells developed on polymer substrates: Effects of low‐temperature processing

Advanced characterization and in-situ growth monitoring of Cu(In,Ga)Se2 thin films and solar cells

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Optical methodology for process monitoring of chalcopyrite photovoltaic technologies: Application to low cost Cu(In,Ga)(S,Se)2 electrodeposition based processes

Cited by 51 publications

References 55 publications

Bandgap imaging in Cu(In,Ga)Se2photovoltaic modules by electroluminescence

Bandgap imaging in Cu(In,Ga)Se2photovoltaic modules by electroluminescence

CZTSe solar cells developed on polymer substrates: Effects of low‐temperature processing

Advanced characterization and in-situ growth monitoring of Cu(In,Ga)Se2 thin films and solar cells

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Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence

Bandgap imaging in Cu(In,Ga)Se₂photovoltaic modules by electroluminescence