Recent progress and challenges in CIGS and CZTS  thin film photovoltaic technologies. Review

Editorial Board PCSS Journal; R.S. Yavorskyi; M.V. Krykhovetskyi

doi:10.15330/pcss.27.1.118-134

Authors

R.S. Yavorskyi Vasyl Stefanyk Carpathian National University, Ivano-Frankivsk, Ukraine
M.V. Krykhovetskyi Vasyl Stefanyk Carpathian National University, Ivano-Frankivsk, Ukraine

DOI:

https://doi.org/10.15330/pcss.27.1.118-134

Keywords:

CIGS, CZTS(Se), thin-film solar cells, photovoltaics, absorber materials, bandgap engineering, defect passivation, renewable energy, efficiency improvement, sustainable technology

Abstract

This review provides a comprehensive analysis of the current state, progress, and challenges of thin-film solar cells based on Cu(In,Ga)Se₂ (CIGS) and Cu₂ZnSn(S,Se)₄ (CZTS(Se)) absorber materials. The study highlights the global transition toward renewable energy, emphasizing the advantages of thin-film photovoltaic technologies as cost-effective, material-efficient, and flexible alternatives to conventional crystalline silicon solar cells. CIGS-based devices demonstrate high power conversion efficiencies exceeding 23%, wide tunability of the bandgap, and excellent long-term stability, making them among the most mature thin-film technologies. However, their dependence on scarce and costly elements such as indium and gallium motivates research into earth-abundant alternatives. CZTS(Se) materials, composed of non-toxic and widely available elements (Cu, Zn, Sn, S, Se), offer a sustainable substitute with comparable optical properties and tunable bandgaps (1.0–1.5 eV). Despite lower efficiencies (currently up to 15.8%), ongoing progress in controlling phase purity, defect passivation, and band alignment is rapidly improving device performance. Key research directions include the optimization of absorber synthesis, defect engineering, alkali-metal and cation doping, and development of environmentally benign, cadmium-free device architectures. The review outlines both the technological maturity of CIGS and the emerging potential of CZTS(Se), identifying critical challenges and future pathways toward high-efficiency, sustainable thin-film photovoltaics.

References

I. Boerasu, B.S. Vasile, Current status of the open-circuit voltage of kesterite CZTS absorber layers for photovoltaic applications—Part I, a review, Materials, 15(23), 8427 (2022); https://doi.org/10.3390/ma15238427.

M.D.K. Jones et al., Ecodesign of kesterite nanoparticles for thin film photovoltaics, ACS Sustain. Chem. Eng. (2024); https://doi.org/10.1021/acssuschemeng.4c02841.

S. Samadi, A review of factors influencing the cost development of electricity generation technologies, Energies 9(11), 970 (2016); https://doi.org/10.3390/en9110970.

C. Ballif et al., Status and perspectives of crystalline silicon photovoltaics in research and industry, Nat. Rev. Mater. 7(8), 597 (2022); https://doi.org/10.1038/s41578-022-00423-2.

K. ElKhamisy, H. Abdelhamid, E.S.M. El-Rabaie, N. Abdel-Salam, A comprehensive survey of silicon thin-film solar cell: challenges and novel trends, Plasmonics, 19(1), 1 (2024); https://doi.org/10.1007/s11468-023-02047-4.

F.M. Tseng, C.H. Hsieh, Y.N. Peng, Y.W. Chu, Using patent data to analyze trends and the technological strategies of the amorphous silicon thin-film solar cell industry, Technol. Forecast. Soc. Change, 78(2), 332 (2011); https://doi.org/10.1016/j.techfore.2010.06.007.

K.P. Bhandari et al., Energy payback time and energy return on energy invested of solar photovoltaic systems, Renew. Sustain. Energy Rev. 47, 133 (2015); https://doi.org/10.1016/j.rser.2015.02.057.

I.V. Vakaliuk, R.S. Yavorskyi, B.P. Naidych, L.I. Nykyruy, L.O. Katanova, O.V. Zamuruieva, Optical Properties of CdTe: In Thin Films Deposited by PVD Technique, J. Nano- Electron. Phys. (2023) 15 (5), 05023 https://doi.org/10.21272/jnep.15(5).05023

A. Faes et al., Building-integrated photovoltaics, Nat. Rev. Clean Technol. (2025).

R. Yavorskyi et al., Structural and optical properties of cadmium telluride obtained by physical vapor deposition technique, Appl. Nanosci. 9(5), 715 (2019); https://doi.org/10.1007/s13204-018-0872-z.

L. Nykyruy et al., CdTe vapor phase condensates on (100) Si and glass for solar cells, Proc. IEEE NAP (2017); https://doi.org/10.1109/NAP.2017.8190161.

S. Malik, Preparation of CuInSe₂ and CuInGaSe₂ nanoparticles and thin films for solar cells applications, PhD Thesis, Univ. of Manchester (2010).

S. Wiedeman et al., Manufacturing ramp-up of flexible CIGS PV, Proc. IEEE PVSC 35, 3485 (2010). https://doi.org/10.1109/PVSC.2010.5614725.

P. Reinhard, S. Buecheler, A.N. Tiwari, Technological status of Cu(In,Ga)(Se,S)₂-based photovoltaics, Sol. Energy Mater. Sol. Cells, 119, 287 (2013); https://doi.org/10.1016/j.solmat.2013.08.030.

K. Machkih et al., A review of CIGS thin film semiconductor deposition via sputtering and thermal evaporation, Coatings, 14, 1088 (2024); https://doi.org/10.3390/coatings14091088.

T. Ghorbani et al., Influence of affinity, band gap and ambient temperature on the efficiency of CIGS solar cells, Optik, 223, 165541 (2020); https://doi.org/10.1016/j.ijleo.2020.165541.

B. Salhi, The photovoltaic cell based on CIGS: principles and technologies, Materials, 15(5), 1908 (2022); https://doi.org/10.3390/ma15051908.

F. Mesa et al., Study of electrical properties of CIGS thin films prepared by multistage processes, Thin Solid Films, 518(7), 1764 (2010); https://doi.org/10.1016/j.tsf.2009.07.161.

W. Witte et al., Gallium gradients in Cu(In,Ga)Se₂ thin-film solar cells, Prog. Photovolt. 23(6), 717 (2015); https://doi.org/10.1002/pip.2478.

N.G. Dhere, Present status and future prospects of CIGSS thin film solar cells, Sol. Energy Mater. Sol. Cells 90(15), 2181 (2006); https://doi.org/10.1016/j.solmat.2006.02.018.

A. Romeo et al., Development of thin-film Cu(In, Ga)Se2 and CdTe solar cells, Prog. Photovolt. 12(2-3), 93 (2004); https://doi.org/10.1002/pip.527.

S. Sakthinathan et al., A review of thin-film growth, properties, applications, and future prospects, Processes 13(2), 587 (2025); https://doi.org/10.3390/pr13020587.

U.C. Matur et al., Optical properties of CIGS thin films derived by sol-gel dip coating, Procedia Soc. Behav. Sci. 195, 1762 (2015); https://doi.org/10.1016/j.sbspro.2015.06.252.

G.G. Buyukgoz et al., Impact of mixing on content uniformity of thin polymer films, Pharmaceutics, 13(6), 812 (2021); https://doi.org/10.3390/pharmaceutics13060812.

M. Singh et al., Thin-film CIGS solar cell based on low-temperature all-printing process, ACS Appl. Mater. Interfaces, 6(18), 16297 (2014); https://doi.org/10.1021/am503689n.

S. Binetti et al., Fabricating CIGS solar cells on flexible substrates by roll-to-roll deposition, Semicond. Sci. Technol. 30(10), 105006 (2015); https://doi.org/10.1088/0268-1242/30/10/105006.

F. Kessler, D. Rudmann, Technological aspects of flexible CIGS solar cells, Sol. Energy, 77(6), 685 (2004); https://doi.org/10.1016/j.solener.2004.05.008.

I. Repins et al., 19.9%-efficient ZnO/CdS/CuInGaSe₂ solar cell, Prog. Photovolt. 16, 235 (2008); https://doi.org/10.1002/pip.822.

A.N. Tiwari et al., 12.8% efficiency Cu(In,Ga)Se₂ solar cell on flexible polymer sheet, Prog. Photovolt. 7(5) (1999); https://doi.org/10.1002/(SICI)1099-159X(199909/10)7:5<393:AID-PIP265>3.0.CO;2-B.

F.S. Hasoon, H.A. Al-Thani, MoSe₂ formation at Mo/CIGS interface, Proc. IEEE PVSC (2016); https://doi.org/10.1109/PVSC.2016.7749882.

A.S. Najm et al., Nucleation and growth mechanism of CdS thin films by CBD, Sci. Rep. 12, 15295 (2022);. https://doi.org/10.1038/s41598-022-19478-3.

R.S. Yavorskyi, Features of optical properties of high stable CdTe photovoltaic absorber layer, Physics and Chemistry of Solid State 21 (2) (2020): 243-253. https://doi.org/10.15330/pcss.21.2.243-253

G. Brammertz et al., Recombination mechanisms in CIGS solar cells, ACS Appl. Mater. Interfaces 17, 46998 (2025); https://doi.org/10.1021/acsami.5c05678.

J. Keller et al., High-concentration silver alloying enabling 23.6% CIGS solar cell, Nat. Energy, 9(4), 467 (2024); https://doi.org/10.1038/s41560-024-01421-3.

E.H. Gorji, Fabrication, electrical characterization and simulation of thin film solar cells, PhD Thesis (2014).

[B.J. Stanbery et al., CIGS photovoltaics: reviewing an evolving paradigm, J. Phys. D Appl. Phys. 55, 173001 (2021); https://doi.org/10.1088/1361-6463/ac2b2f.

L. Dong et al., Grain-boundary passivation in CZTSSe solar cells by Na doping, Sol. RRL 7, 2300061 (2023); https://doi.org/10.1002/solr.202300061.

I. Repins et al., Required materials properties for high-efficiency CIGS modules, NREL Report (2009); https://doi.org/10.2172/956774.

M. Gloeckler, J.R. Sites, Band-gap grading in Cu(In,Ga)Se₂ solar cells, J. Phys. Chem. Solids, 66(11), 1891 (2005); https://doi.org/10.1016/j.jpcs.2005.09.087.

G. Wisz et al., Structure defects and photovoltaic properties of TiO₂:ZnO/CuO solar cells, Appl. Sci. 13, 3613 (2023); https://doi.org/10.3390/app13063613.

E.H. Alruqobah, R. Agrawal, Potassium treatments for solution-processed CIGS solar cells, ACS Appl. Energy Mater. 3, 4821 (2020); https://doi.org/10.1021/acsaem.0c00418.

A.C. Badgujar et al., Atmospheric selenization of spray-casted CIGS layers, Sol. Energy, 209, 1 (2020); https://doi.org/10.1016/j.solener.2020.08.080.

V. Sharma, S.S. Chandel, Performance and degradation analysis of PV systems, Renew. Sustain. Energy Rev. 27, 753 (2013); https://doi.org/10.1016/j.rser.2013.07.023.

M.Y. Zaki, A. Velea, Secondary phases in kesterite CZTSSe thin films, Energies, 17(7), 1600 (2024); https://doi.org/10.3390/en17071600.

M. Kangsabanik, R.N. Gayen, Cation substitution in CZTSSe thin films, Sol. RRL 7, 2300670 (2023); https://doi.org/10.1002/solr.202300670.

M. Kumar et al., Secondary phases and defect complexes in kesterite CZTSSe, Energy Environ. Sci. 8, 3134 (2015); https://doi.org/10.1039/C5EE02153G.

M. Kumar, C. Persson, Cu₂ZnSnS₄ and Cu₂ZnSnSe₄ absorber materials, Int. J. Theor. Appl. Sci. 5, 1 (2013).

E. Lund et al., Beneficial cation arrangement in Cu-rich CZTS, J. Appl. Phys. 115, 173503 (2014); https://doi.org/10.1063/1.4871665.

S. Chen et al., Intrinsic point defects in Cu₂ZnSnS₄, Phys. Rev. B 81, 245204 (2010); https://doi.org/10.1103/PhysRevB.81.245204.

K. Sun et al., Over 9% efficient CZTS solar cell fabricated by oxide precursor route, ACS Energy Lett. 2, 1859 (2017); https://doi.org/10.1021/acsenergylett.7b00388.

K. Sun et al., Over 9% efficient CZTS solar cell using Zn₁₋ₓCdₓS buffer, Adv. Energy Mater. 6, 1600046 (2016); https://doi.org/10.1002/aenm.201600046.

D. Shin et al., Enhanced CIGS performance by alkali post-deposition treatments, Sol. Energy Mater. Sol. Cells, 95, 146 (2011); https://doi.org/10.1016/j.solmat.2010.04.056.

M. Werner et al., 8.3% efficient CZTSSe solar cells from solution precursors, Thin Solid Films, 582, 308 (2015); https://doi.org/10.1016/j.tsf.2014.11.071.

T.C. Mangan et al., Thermochemical aspects of CZTSSe thin film growth, J. Appl. Phys. 118, 065304 (2015); https://doi.org/10.1063/1.4928057.

Y. Yusoff et al., Atmospheric pressure vapor phase epitaxy of ZnS, Mater. Lett. 221, 216 (2018); https://doi.org/10.1016/j.matlet.2018.03.106.

J. Just et al., Secondary phases and their influence on the composition of the kesterite phase in CZTS and CZTSe thin films, Phys. Chem. Chem. Phys. 18(23), 15988 (2016); https://doi.org/10.1039/C6CP00178E.

H. Guan et al., Fabrication of CZTS thin films by solution method, J. Mater. Sci. Mater. Electron. 28, 14424 (2017); https://doi.org/10.1007/s10854-017-7244-5.

Y. Mao et al., 12.86% efficient CZTSSe solar cells via inkjet printing, Adv. Funct. Mater. 35, 2416689 (2025); https://doi.org/10.1002/adfm.202416689.

R. Agrawal, Development of low-cost technology for earth-abundant solar cells, Technical Report (2014).

H.W. Schock, Thin film photovoltaics, Appl. Surf. Sci. 92, 606 (1996); https://doi.org/10.1016/0169-4332(95)00363-0.

S.M. Sivasankar et al., Progress in thin-film photovoltaics, J. Compos. Sci. 9(3), 143 (2025); https://doi.org/10.3390/jcs9030143.

A. Emrani, Fabrication and characterization of CZTS thin films, PhD Thesis (2014).

G. Altamura, J. Vidal, Impact of minor phases on the performances of CZTSSe thin-film solar cells, Chem. Mater. 28(11), 3540 (2016); https://doi.org/10.1021/acs.chemmater.6b00069.

S. Sivaraj et al., A comprehensive review on thin-film solar cells, Energies, 15(22), 8688 (2022); https://doi.org/10.3390/en15228688.

G. Wisz, P. Sawicka-Chudy, R. Yavorskyi, P. Potera, M. Bester, TiO2/Cu2O heterojunctions for photovoltaic cells application produced by reactive magnetron sputtering, Materials Today: Proceedings, 2021, 35, 552-557. https://doi.org/10.1016/j.matpr.2019.10.054.

T. Ahamed et al., Optimization of buffer layers for CZTSSe solar cells, J. Phys. Chem. Solids, 204, 112744 (2025); https://doi.org/10.1016/j.jpcs.2024.112744.

S.R. Kodigala, Thin film solar cells from earth abundant materials, Book (2013).

S. Saha, Status review on CZTS-based thin-film solar cells, Int. J. Photoenergy, 2020, 3036413 (2020); https://doi.org/10.1155/2020/3036413.

B.K. Durant, B.A. Parkinson, Photovoltaic response of natural kesterite crystals, Sol. Energy Mater. Sol. Cells, 144, 586 (2016); https://doi.org/10.1016/j.solmat.2015.09.024.

K. Kaur, M. Kumar, CZTSSe/CdS interface engineering, J. Mater. Chem. A 8, 21547 (2020); https://doi.org/10.1039/D0TA06027G.

T.R. Rana et al., Potassium fluoride treated CZTSSe solar cell, Curr. Appl. Phys. 17, 1353 (2017); https://doi.org/10.1016/j.cap.2017.07.007.

S.W. Shin et al., CZTS absorber layer using different stacking orders, Sol. Energy Mater. Sol. Cells, 95, 3202 (2011); https://doi.org/10.1016/j.solmat.2011.06.012.

R. Charghandeh, A. Abbasi, Effect of In(O,S) buffer layer on CZTSSe solar cells, Mater. Today Commun. 37, 107299 (2023); https://doi.org/10.1016/j.mtcomm.2023.107299.

H. Wang, Progress in thin film solar cells based on Cu2ZnSnS4, Int. J. Photoenergy 2011(1), 801292 (2011); https://doi.org/10.1155/2011/801292.