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Title: Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se 2 solar cells on glass substrate

Abstract

The precise control of alkali-metal concentrations in Cu(In,Ga)Se 2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominantmore » effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.« less

Authors:
ORCiD logo [1];  [1]; ORCiD logo [1];  [1];  [2];  [1];  [1];  [1]
  1. National Inst. of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1429975
Report Number(s):
NREL/JA-5K00-71194
Journal ID: ISSN 0021-8979; TRN: US1802487
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 9; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; materials; electrochemistry; metals; diffusion; condensed matter properties; mass spectrometry; electrical properties; materials treatment; liquids; metalloids

Citation Formats

Kamikawa, Yukiko, Nishinaga, Jiro, Ishizuka, Shogo, Tayagaki, Takeshi, Guthrey, Harvey, Shibata, Hajime, Matsubara, Koji, and Niki, Shigeru. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate. United States: N. p., 2018. Web. doi:10.1063/1.5016949.
Kamikawa, Yukiko, Nishinaga, Jiro, Ishizuka, Shogo, Tayagaki, Takeshi, Guthrey, Harvey, Shibata, Hajime, Matsubara, Koji, & Niki, Shigeru. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate. United States. https://doi.org/10.1063/1.5016949
Kamikawa, Yukiko, Nishinaga, Jiro, Ishizuka, Shogo, Tayagaki, Takeshi, Guthrey, Harvey, Shibata, Hajime, Matsubara, Koji, and Niki, Shigeru. Wed . "Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate". United States. https://doi.org/10.1063/1.5016949. https://www.osti.gov/servlets/purl/1429975.
@article{osti_1429975,
title = {Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate},
author = {Kamikawa, Yukiko and Nishinaga, Jiro and Ishizuka, Shogo and Tayagaki, Takeshi and Guthrey, Harvey and Shibata, Hajime and Matsubara, Koji and Niki, Shigeru},
abstractNote = {The precise control of alkali-metal concentrations in Cu(In,Ga)Se2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.},
doi = {10.1063/1.5016949},
url = {https://www.osti.gov/biblio/1429975}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 9,
volume = 123,
place = {United States},
year = {2018},
month = {3}
}

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Cited by: 6 works
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Figures / Tables:

Table I Table I: Solar-cell parameters for the CIGS solar cells with absorbers annealed at 350 °C and 550 °C with low flux KF irradiation and without KF addition and the as-grown CIGS solar cell. The diode parameters obtained by fitting dark J–V curves are also listed. T an is the annealingmore » temperature, E ff. is the solar-cell conversion efficiency, R sh is the shunt resistance, R s is the series resistance, J 0 is the reverse saturation current density, and m is the ideality factor.« less

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Works referenced in this record:

Effects of alkali-metal block layer to enhance Na diffusion into Cu(in,Ga)Se2 absorber on flexible solar cells
journal, February 2015


Highly Efficient Cu(In,Ga)Se 2 Thin-Film Submodule Fabricated Using a Three-Stage Process
journal, November 2013


Unveiling the effects of post-deposition treatment with different alkaline elements on the electronic properties of CIGS thin film solar cells
journal, January 2014


High‐efficiency CuIn x Ga 1− x Se 2 solar cells made from (In x ,Ga 1− x ) 2 Se 3 precursor films
journal, July 1994


Characterization of Grain Boundaries in Cu(In,Ga)Se$_{\bf 2}$ Films Using Atom-Probe Tomography
journal, October 2011


Effects of Na on the electrical and structural properties of CuInSe2
journal, May 1999


Effect of Alkali Metal Atom Doping on the CuInSe 2 -Based Solar Cell Absorber
journal, July 2017


n -type doping of CuIn Se 2 and CuGa Se 2
journal, July 2005


Effect of Cu deficiency on the optical bowing of chalcopyrite CuIn1−xGaxSe2
journal, October 2005


Na incorporation into Cu(In,Ga)Se2 for high-efficiency flexible solar cells on polymer foils
journal, April 2005


Solar cell efficiency tables (version 50)
journal, June 2017

  • Green, Martin A.; Hishikawa, Yoshihiro; Warta, Wilhelm
  • Progress in Photovoltaics: Research and Applications, Vol. 25, Issue 7
  • https://doi.org/10.1002/pip.2909

Effects of long-term heat-light soaking on Cu(In,Ga)Se 2 solar cells with KF postdeposition treatment
journal, August 2017


Potassium-induced surface modification of Cu(In,Ga)Se2 thin films for high-efficiency solar cells
journal, November 2013


Features of KF and NaF Postdeposition Treatments of Cu(In,Ga)Se 2 Absorbers for High Efficiency Thin Film Solar Cells
journal, August 2015


Defect physics of the CuInSe 2 chalcopyrite semiconductor
journal, April 1998


Sodium Passivation of the Grain Boundaries in CuInSe 2 and Cu 2 ZnSnS 4 for High-Efficiency Solar Cells
journal, December 2016


Impact of Cu/III ratio on the near-surface defects in polycrystalline CuGaSe2 thin films
journal, March 2011


Effects of heavy alkali elements in Cu(In,Ga)Se 2 solar cells with efficiencies up to 22.6%
journal, July 2016


A critical review on building integrated photovoltaic products and their applications
journal, August 2016


First-principles study on alkali-metal effect of Li, Na, and K in CuInSe 2 and CuGaSe 2
journal, July 2015


Diffusion barrier properties of molybdenum back contacts for Cu(In,Ga)Se 2 solar cells on stainless steel foils
journal, February 2013


Surface treatment of CuInGaSe2 thin films and its effect on the photovoltaic properties of solar cells
journal, September 2003


Progress in thin film CIGS photovoltaics - Research and development, manufacturing, and applications: Progress in thin film CIGS photovoltaics
journal, October 2016


Cu(In,Ga)(Se,S) 2 solar cell research in Solar Frontier: Progress and current status
journal, February 2017


Effect of Cu-deficient layer formation in Cu(In,Ga)Se 2 solar-cell performance
journal, December 2017


Effects of Mo surface oxidation on Cu(In,Ga)Se 2 solar cells fabricated by three-stage process with KF postdeposition treatment
journal, January 2016


Effects of Sodium on Polycrystalline Cu(In,Ga)Se2 and Its Solar Cell Performance
journal, January 1998


Interpretation of admittance, capacitance-voltage, and current-voltage signatures in Cu(In,Ga)Se2 thin film solar cells
journal, February 2010


CIGS thin-film solar cells on steel substrates
journal, February 2009


Optimization of CBD CdS process in high-efficiency Cu(In,Ga)Se2-based solar cells
journal, February 2002


Investigation of the diffusion behavior of sodium in Cu(In,Ga)Se 2 layers
journal, April 2014


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