Advancing kesterite absorbers with bronze-based precursors through physical deposition routes: a step toward stable and sustainable industrial photovoltaic technology

Abstract

This work presents, for the first time, a direct comparison of the impact of applying elemental metallic stack precursors and bronze-based precursors to produce Cu₂ZnSnSe₄ (CZTSe)-based solar cells by sequential fabrication based on physical deposition methods. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction reveal an improved morphology, a higher compositional homogeneity, and a higher presence of binary alloys in the bronze-based precursor. Scanning electron microscopy observation also shows that bronze-based precursors improve the thickness homogeneity and the rear interface morphology of CZTSe absorbers, while Raman spectroscopy detects an improved crystalline quality and an improved structural micro-homogeneity at the absorber surface. The results of this work also demonstrate that germanium doping, which is required when applying elemental metallic stack precursors, can be avoided in the case of bronze-based precursors without compromising the efficiency of the solar cells. Thus, this work sheds light on the mechanisms induced by bronze-based precursors that contribute to producing high-efficiency CZTSe-based devices, so the expanded understanding of this precursor can help to further optimize such devices. Additionally, this work demonstrates that the bronze-based precursor reduces material, energy, and time consumption, which favors its possible scaling up to an industrial level.

Keywords

Kesterite / metallic precursor / solar cells / sputtering / technology industrialization

References

[1] Kinnaird JA.Critical raw materials.In: Yakovleva, N.; Nickless, E.; editors. Routledge handbook of the extractive industries and sustainable development. London: Routledge; 2022. pp. 13-33.

[2] Lee TD.A review of thin film solar cell technologies and challenges.Renew Sustain Energy Rev2017;70:1286-97

[3] Candelise C,Gross R.Implications for CdTe and CIGS technologies production costs of indium and tellurium scarcity.Prog Photovolt Res Appl2012;20:816-31

[4] Wang A,Sun K.Analysis of manufacturing cost and market niches for Cu₂ZnSnS₄ (CZTS) solar cells.Sustain Energy Fuels2021;5:1044-58

[5] Li J,Yuan X,Green MA.Emergence of flexible kesterite solar cells: progress and perspectives.npj Flex Electron2023;7:16

[6] Tripathi S,Kumar B.Comparative analysis of CZTS/CZTSe/CZTSSe absorber layer for solar cell applications. In: 2020 International Conference on Electrical and Electronics Engineering (ICE3); 2020 Feb 14-15; Gorakhpur, India. IEEE; 2020. pp. 588-91.

[7] Andrade-Arvizu J,Becerril-Romero I.Is it possible to develop complex S-Se graded band gap profiles in kesterite-based solar cells?.ACS Appl Mater Interfaces2019;11:32945-56

[8] Andrade-arvizu J,Sánchez Y.Rear band gap grading strategies on Sn-Ge-alloyed kesterite solar cells.ACS Appl Energy Mater2020;3:10362-75

[9] Andrade-Arvizu J,Izquierdo-Roca V.Controlling the anionic ratio and gradient in kesterite technology.ACS Appl Mater Interfaces2022;14:1177-86 PMCID:PMC8762644

[10] Mathews I,Buonassisi T.Technology and market perspective for indoor photovoltaic cells.Joule2019;3:1415-26

[11] Ghosh A.Potential of building integrated and attached/applied photovoltaic (BIPV/BAPV) for adaptive less energy-hungry building’s skin: a comprehensive review.J Clean Prod2020;276:123343

[12] Dinesh H.The potential of agrivoltaic systems.Renew Sustain Energy Rev2016;54:299-308

[13] Green MA,Yoshita M.Solar cell efficiency tables (Version 63).Prog Photovolt Res Appl2024;32:3-13Available from: https://onlinelibrary.wiley.com/doi/full/10.1002/pip.3750. [Last accessed on 26 Mar 2025]

[14] Grenet L,Emieux F.Analysis of failure modes in kesterite solar cells.ACS Appl Energy Mater2018;1:2103-13

[15] Fonoll-rubio R,Blanco-portals J.Insights into interface and bulk defects in a high efficiency kesterite-based device.Energy Environ Sci2021;14:507-23

[16] Schorr S,Guc M.Point defects, compositional fluctuations, and secondary phases in non-stoichiometric kesterites.J Phys Energy2020;2:012002

[17] Li J,Ma F.Unveiling microscopic carrier loss mechanisms in 12% efficient Cu₂ZnSnSe₄ solar cells.Nat Energy2022;7:754-64

[18] Giraldo S,Placidi M,Pérez-Rodríguez A.Progress and perspectives of thin film kesterite photovoltaic technology: a critical review.Adv Mater2019;31:1806692

[19] Zhou J,Wu H.Control of the phase evolution of kesterite by tuning of the selenium partial pressure for solar cells with 13.8% certified efficiency.Nat Energy2023;8:526-35

[20] Gong Y,Zhu Q.Identifying the origin of the V_oc deficit of kesterite solar cells from the two grain growth mechanisms induced by Sn²⁺ and Sn⁴⁺ precursors in DMSO solution.Energy Environ Sci2021;14:2369-80

[21] Gong Y,Jedlicka E.Sn⁴⁺ precursor enables 12.4% efficient kesterite solar cell from DMSO solution with open circuit voltage deficit below 0.30 V.Sci China Mater2021;64:52-60

[22] Ratz T,Caballero R.Physical routes for the synthesis of kesterite.J Phys Energy2019;1:042003

[23] Giraldo S,Neuschitzer M.How small amounts of Ge modify the formation pathways and crystallization of kesterites.Energy Environ Sci2018;11:582-93

[24] Hernández-martínez A,Arqués L.Insights into the formation pathways of Cu₂ZnSnSe₄ using rapid thermal processes.ACS Appl Energy Mater2018;1:1981-9

[25] Giraldo S,Andrade-arvizu JA.Study and optimization of alternative MBE-deposited metallic precursors for highly efficient kesterite CZTSe:Ge solar cells.Prog Photovolt Res Appl2019;27:779-88

[26] Taskesen T,Chen W.Resilient and reproducible processing for CZTSe solar cells in the range of 10%.Prog Photovolt Res Appl2018;26:1003-6

[27] Taskesen T,Schoneberg J.Device characteristics of an 11.4% CZTSe solar cell fabricated from sputtered precursors.Adv Energy Mater2018;8:1703295

[28] Pareek D,Márquez JA.Reaction pathway for efficient Cu₂ZnSnSe₄ solar cells from alloyed Cu-Sn Precursor via a Cu-rich selenization stage.Solar RRL2020;4:2000124

[29] Taskesen T,Nowak D.Potential of CZTSe solar cells fabricated by an alloy-based processing strategy.Z Naturforsch A2019;74:673-82

[30] González-castillo J,Rodríguez E,Leal J.Cu₆Sn₅ binary phase as a precursor material of the CZTSe compound: optimization of the synthesis process, physical properties and its performance as an absorbing material in a solar cell.Mater Scie Semicond Process2021;134:106016

[31] Giraldo S,Thersleff T.Large efficiency improvement in Cu₂ZnSnSe₄ solar cells by introducing a superficial Ge nanolayer.Adv Energy Mater2015;5:1501070

[32] Fairbrother A,Fontané X.Precursor stack ordering effects in Cu₂ZnSnSe₄ thin films prepared by rapid thermal processing.J Phys Chem C2014;118:17291-8

[33] Nowak D,Pareek D,Mikolajczak U.Tuning of precursor composition and formation pathway of kesterite absorbers using an in-process composition shift: a path toward higher efficiencies?.Solar RRL2021;5:2100237

[34] Nowak D,Pareek D.Influence of the precursor composition on the resulting absorber properties and defect concentration in Cu₂ZnSnSe₄ absorbers.Sol Energy Mater Sol Cells2023;256:112342

[35] Delbos S.Kësterite thin films for photovoltaics : a review.EPJ Photovolt2012;3:35004

[36] Márquez J,Dimitrievska M.Systematic compositional changes and their influence on lattice and optoelectronic properties of Cu₂ZnSnSe₄ kesterite solar cells.Sol Energy Mater Sol Cells2016;144:579-85

[37] Heriche H,Bouarissa N.New ultra thin CIGS structure solar cells using SCAPS simulation program.Int J Hydrogen Energy2017;42:9524-32

[38] Leonard E,Tomassini M,Marrón DF.Cu(In,Ga)Se₂ absorber thinning and the homo-interface model: influence of Mo back contact and 3-stage process on device characteristics.J Appl Phys2014;116:074512

[39] Jehl Z,Naghavi N.Thinning of CIGS solar cells: part II: cell characterizations.Thin Solid Films2011;519:7212-5

[40] Cheon KB,Seo SW,Park MA.Roughness-controlled Cu₂ZnSn(S,Se)₄ thin-film solar cells with reduced charge recombination.ACS Appl Mater Interfaces2019;11:24088-95

[41] Scragg JJ,Colombara D.Thermodynamic aspects of the synthesis of thin-film materials for solar cells.Chemphyschem2012;13:3035-46

[42] López-marino S,Pérez-tomás A.Inhibiting the absorber/Mo-back contact decomposition reaction in Cu₂ZnSnSe₄ solar cells: the role of a ZnO intermediate nanolayer.J Mater Chem A2013;1:8338

[43] Karade V,Babar P.Insights into kesterite’s back contact interface: a status review.Sol Energy Mater Sol Cells2019;200:109911

[44] Dimitrievska M,Guc M.Defect characterisation in Cu₂ZnSnSe₄ kesterites via resonance Raman spectroscopy and the impact on optoelectronic solar cell properties.J Mater Chem A2019;7:13293-304

[45] Weber A,Perlt S.Multi-stage evaporation of Cu₂ZnSnS₄ thin films.Thin Solid Films2009;517:2524-6

[46] Stanchik A,Juskenas R.Effects of selenization time and temperature on the growth of Cu₂ZnSnSe₄ thin films on a metal substrate for flexible solar cells.Solar Energy2019;178:142-9

[47] Redinger A,Dale PJ.The consequences of kesterite equilibria for efficient solar cells.J Am Chem Soc2011;133:3320-3

[48] Guo T,Liu L,Zhang Y.Effect of substrate and selenization temperature on the properties of RF sputtered CZTSe layer.Vacuum2017;145:217-24