CuIn (Se,Te)2 Absorbers With Bandgaps <1 eV for Bottom Cells in Tandem Applications

chalcopyrite; low gap; tandem solar cells; Absorber layers; Bottom cells; Cell-be; Cell/B.E; Chalcopyrite; Higher efficiency; Low carbon; Low gap; Tandem solar cells; Thin-films; Electronic, Optical and Magnetic Materials; Renewable Energy, Sustainability and the Environment; Condensed Matter Physics; Electrical and Electronic Engineering

Abstract :

[en] Thin-film solar cells reach high efficiencies and have a low carbon footprint in production. Tandem solar cells have the potential to significantly increase the efficiency of this technology, where the bottom-cell is generally composed of a Cu(In,Ga)Se2 absorber layer with bandgaps around 1 eV or higher. Here, we investigate CuIn(Se1 − xTex)2 absorber layers and solar cells with bandgaps below 1 eV, which will bring the benefit of an additional degree of freedom for designing current-matched two-terminal tandem devices. We report that CuIn(Se1 − xTex)2 thin films can be grown single phase by co-evaporation and that the bandgap can be reduced to the optimum range (0.92–0.95 eV) for a bottom cell. From photoluminescence spectroscopy, it is found that no additional non-radiative losses are introduced to the absorber when adding Te. However, (Formula presented.) losses occur in the final solar cell due to non-optimized interfaces. Nevertheless, a device with 9% power conversion efficiency is demonstrated with a bandgap of 0.97 eV and (Formula presented.), the highest efficiency so far for chalcopyrites with band gap <1 eV. Interface recombination is identified as a major recombination channel for larger Te contents. Thus, further efficiency improvements can be expected with improved absorber/buffer interfaces.

Disciplines :

Physics

Author, co-author :

WEISS, Thomas ; University of Luxembourg > Faculty of Science, Technology and Medicine > Department of Physics and Materials Science > Team Susanne SIEBENTRITT

SOOD, Mohit ; University of Luxembourg > Faculty of Science, Technology and Medicine > Department of Physics and Materials Science > Team Alex REDINGER

VANDERHAEGEN, Aline Inez Dominique ; University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Physics and Materials Science (DPHYMS)

SIEBENTRITT, Susanne ; University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Physics and Materials Science (DPHYMS)

External co-authors :

yes

Language :

English

Title :

CuIn (Se,Te)2 Absorbers With Bandgaps <1 eV for Bottom Cells in Tandem Applications

Publication date :

2024

Journal title :

Progress in Photovoltaics

ISSN :

1062-7995

eISSN :

1099-159X

Publisher :

John Wiley and Sons Ltd

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pip.3851

Available on ORBilu :

since 26 May 2025

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Bibliography

E. G. Hertwich, J. Aloisi de Larderel, A. Arvesen, et al., Green Energy Choices: The Benefits, Risks and Trade-Offs of Low-Carbon Technologies for Electricity Production (New York: United Nation's Environment Programme, 2016), 2016.
W. Shockley and H. J. Queisser, “Detailed Balance Limit of Efficiency ofp-nJunction Solar Cells,” Journal of Applied Physics 32 (1961): 510–519.
M. A. Green, E. D. Dunlop, M. Yoshita, et al., “Solar Cell Efficiency Tables (Version 62),” Progress in Photovoltaics: Research and Applications 31 (2023): 651–663.
M. Jošt, E. Köhnen, A. Al-Ashouri, et al., “Perovskite/CIGS Tandem Solar Cells: From Certified 24.2% Toward 30% and Beyond,” ACS Energy Letters 7 (2022): 1298–1307.
T. Feeney, I. M. Hossain, S. Gharibzadeh, et al., “Four-Terminal Perovskite/Copper Indium Gallium Selenide Tandem Solar Cells: Unveiling the Path to >27% in Power Conversion Efficiency,” Solar RRL 6 (2022): 2200662.
https://www.kaust.edu.sa/en/news/kaust-team-sets-world-record-for-tandem-solar-cell-efficiency.
T. C. J. Yang, P. Fiala, Q. Jeangros, and C. Ballif, “High-Bandgap Perovskite Materials for Multijunction Solar Cells,” Joule 2 (2018): 1421–1436.
A. Zunger and S.-H. Wei, “Electronic Structure Theory of Chalcopyrite Alloys, Interfaces, and Ordered Vacancy Compounds,” AIP Conference Proceedings 353 (1996): 155–160.
R. Diaz, M. León, and F. Rueda, “Characterization of Cu-In-Se-Te System in Thin Films Grown by Thermal Evaporation,” Journal of Vacuum Science & Technology, A: Vacuum, Surfaces, and Films 10 (1992): 295–300.
Z. Jehl-Li-Kao, T. Kobayashi, and T. Nakada, “CuIn(Se1−xTex)2 Solar Cells With Tunable Narrow-Bandgap for Bottom Cell Application in Multijunction Photovoltaic Devices,” Solar Energy Materials and Solar Cells 119 (2013): 144–148.
H. Hiroi, Y. Iwata, S. Adachi, H. Sugimoto, and A. Yamada, “New World-Record Efficiency for Pure-Sulfide Cu(In,Ga)S2 Thin-Film Solar Cell With Cd-Free Buffer Layer via KCN-Free Process,” IEEE Journal of Photovoltaics 6, no. 3 (2016): 760–763.
R. Mallick, X. Li, C. Reich, et al., “Arsenic-Doped CdSeTe Solar Cells Achieve World Record 22.3% Efficiency,” IEEE Journal of Photovoltaics 13 (2023): 510–515.
M. Langenhorst, B. Sautter, R. Schmager, et al., “Energy Yield of All Thin-Film Perovskite/CIGS Tandem Solar Modules,” Progress in Photovoltaics: Research and Applications 27 (2019): 290–298.
J. E. Avon, K. Yoodee, and J. C. Woolley, “Solid Solution, Lattice Parameter Values, and Effects of Electronegativity in the (Cu1−xAgx)(Ga1−yIny)(Se1−zTez)2 Alloys,” Journal of Applied Physics 55 (1984): 524–535.
Z. J. Li-Kao, T. Kobayashi, and T. Nakada, in Conference Record of the IEEE Photovoltaic Specialists Conference (2013), 3402.
A. M. Gabor, J. R. Tuttle, D. S. Albin, M. A. Contreras, R. Noufi, and A. M. Hermann, “High-Efficiency CuInxGa1−xSe2 Solar Cells Made From (Inx,Ga1−x)2Se3 Precursor Films,” Applied Physics Letters 65 (1994): 198–200.
T. P. Weiss, O. Ramirez, S. Paetel, et al., “Metastable Defects Decrease the Fill Factor of Solar Cells,” Physical Review Applied 19 (2023): 024052.
P. Würfel, “The Chemical Potential of Radiation,” Journal of Physics C: Solid State Physics 15 (1982): 3967–3985.
S. Siebentritt, T. P. Weiss, M. Sood, M. H. Wolter, A. Lomuscio, and O. Ramirez, “How Photoluminescence Can Predict the Efficiency of Solar Cells,” Journal of Physics: Materials 4 (2021): 042010.
M. H. Wolter, B. Bissig, E. Avancini, et al., “Influence of Sodium and Rubidium Postdeposition Treatment on the Quasi-Fermi Level Splitting of Cu(In,Ga)Se2Thin Films,” IEEE Journal of Photovoltaics 8 (2018): 1320–1325.
T. Trupke, R. A. Bardos, M. D. Abbott, and J. E. Cotter, “Suns-Photoluminescence: Contactless Determination of Current-Voltage Characteristics of Silicon Wafers,” Applied Physics Letters 87 (2005): 093503.
F. Babbe, L. Choubrac, and S. Siebentritt, “The Optical Diode Ideality Factor Enables Fast Screening of Semiconductors for Solar Cells,” Solar RRL 2 (2018): 1800248.
U. Rau, B. Blank, T. C. M. Müller, and T. Kirchartz, “Efficiency Potential of Photovoltaic Materials and Devices Unveiled by Detailed-Balance Analysis,” Physical Review Applied 7 (2017): 044016.
C. Hönes, (Diss., University of Luxembourg, 2016).
W. E. Vargas, D. E. Azofeifa, and N. Clark, “Retrieved Optical Properties of Thin Films on Absorbing Substrates From Transmittance Measurements by Application of a Spectral Projected Gradient Method,” Thin Solid Films 425 (2003): 1–8.
T. P. Weiss, P. Arnou, M. Melchiorre, et al., “Thin-Film(Sb,Bi)2Se3Semiconducting Layers With Tunable Band Gaps Below 1 eV for Photovoltaic Applications,” Physical Review Applied 14 (2020): 024014.
P. Yu and M. Cardona, Fundamentals of Semicondcutors, 4th ed., (Berlin Heidelberg: Springer-Verlag, 2010).
D. Regesch, L. Gütay, J. K. Larsen, et al., “Degradation and Passivation of CuInSe2,” Applied Physics Letters 101 (2012): 112108.
F. Babbe, L. Choubrac, and S. Siebentritt, “Quasi Fermi Level Splitting of Cu-Rich and Cu-Poor Cu(In,Ga)Se2 Absorber Layers,” Applied Physics Letters 109 (2016): 082105.
S. Siebentritt, U. Rau, S. Gharabeiki, et al., “Photoluminescence Assessment of Materials for Solar Cell Absorbers,” Faraday Discussions 239 (2022): 112–129.
J. K. Larsen, S. Y. Li, J. J. S. Scragg, et al., “Interference Effects in Photoluminescence Spectra of Cu2ZnSnS4 and Cu(In,Ga)Se2 Thin Films,” Journal of Applied Physics 118 (2015): 035307.
M. H. Wolter, B. Bissig, P. Reinhard, S. Buecheler, P. Jackson, and S. Siebentritt, “Physica Status Solidi (C) Current Topics,” Solid State Physics 6 (2017): 1600189.
U. Rau and J. H. Werner, “Radiative Efficiency Limits of Solar Cells With Lateral Band-Gap Fluctuations,” Applied Physics Letters 84 (2004): 3735–3737.
M. Sood, A. Urbaniak, C. K. Boumenou, et al., “Near Surface Defects: Cause of Deficit Between Internal and External Open-Circuit Voltage in Solar Cells,” Progress in Photovoltaics 30 (2022): 263–275.
R. Scheer and H. W. Schock, Chalcogenide Photovoltaics: Physics, Technologies, and Thin Film Devices (Weinheim: Wiley-VCH, 2011).
T. Bertram, V. Deprédurand, and S. Siebentritt, in 40th IEEE Photovoltaic Specialist Conference (IEEE, Denver, 2014), 3633.
V. Depredurand, Y. Aida, J. Larsen, A. Majerus, and S. Siebentritt, in 37th IEEE Photovoltaic Specialist Conference (IEEE, Seattle, 2011), 337.
R. T. Ross, “Some Thermodynamics of Photochemical Systems,” The Journal of Chemical Physics 46 (1967): 4590.
M. Maiberg and R. Scheer, “Theoretical Study of Time-Resolved Luminescence in Semiconductors. I. Decay From the Steady State,” Journal of Applied Physics 116 (2014): 123710.
T. Otaredian, “Separate Contactless Measurement of the Bulk Lifetime and the Surface Recombination Velocity by the Harmonic Optical Generation of the Excess Carriers,” Solid State Electronics 36 (1993): 153–162.
T. P. Weiss, B. Bissig, T. Feurer, R. Carron, S. Buecheler, and A. N. Tiwari, “Bulk and Surface Recombination Properties in Thin Film Semiconductors With Different Surface Treatments From Time-Resolved Photoluminescence Measurements,” Scientific Reports 9 (2019): 5385.
M. Maiberg and R. Scheer, “Theoretical Study of Time-Resolved Luminescence in Semiconductors. II. Pulsed Excitation,” Journal of Applied Physics 116 (2014): 123711.
M. Maiberg, T. Hölscher, S. Zahedi-Azad, and R. Scheer, “Theoretical Study of Time-Resolved Luminescence in Semiconductors. III. Trap States in the Band Gap,” Journal of Applied Physics 118 (2015): 105701.
S. J. Heise and J. F. López Salas, “Charge Separation Effects in Time-Resolved Photoluminescence of Cu(In,Ga)Se2 Thin Film Solar Cells,” Thin Solid Films 633 (2017): 35–39.
F. Pianezzi, P. Reinhard, A. Chirilă, et al., “Unveiling the Effects of Post-Deposition Treatment With Different Alkaline Elements on the Electronic Properties of CIGS Thin Film Solar Cells,” Physical Chemistry Chemical Physics 16 (2014): 8843–8851.
T. P. Weiss, F. Ehre, V. Serrano-Escalante, T. Wang, and S. Siebentritt, “Understanding Performance Limitations of Cu(In,Ga)Se2Solar Cells due to Metastable Defects—A Route Toward Higher Efficiencies,” Solar RRL 5 (2021): 2100063.
T. P. Weiss, O. Ramírez, S. Paetel, W. Witten, J. Nishinaga, T. Feurer, and S. Siebentritt, (in revision, 2022).
T. Wang, F. Ehre, T. P. Weiss, et al., “Diode Factor in Solar Cells With Metastable Defects and Back Contact Recombination,” Advanced Energy Materials 12 (2022): 2202076.
R. Scheer and H. W. Schock, Chalcogenide Photovoltaics: Physics, Technologies, and Thin Film Devices (Weinheim, Germany: Wiley-VCH Verlag & Co. KGaA, 2011).
M. Sood, D. Adeleye, S. Shukla, T. Törndahl, A. Hultqvist, and S. Siebentritt, “Faraday Discussions,” (2022).
J. Keller, K. V. Sopiha, O. Stolt, et al., “Wide-gap (Ag,Cu)(In,Ga)Se2 Solar Cells With Different Buffer Materials—A Path to a Better Heterojunction,” Progress in Photovoltaics: Research and Applications 28 (2020): 237–250.
M. Sood, P. Gnanasambandan, D. Adeleye, et al., “Electrical Barriers and Their Elimination by Tuning (Zn,Mg)O Buffer Composition in Cu(In,Ga)S2 Solar Cells: Systematic Approach to Achieve Over 14% Power Conversion Efficiency,” Journal of Physics: Energy 4 (2022): 045005.
T. Kirchartz and U. Rau, “What Makes a Good Solar Cell?” Advanced Energy Materials 8 (2018): 1703385.