Phase separation in wurtzite CuInxGa1−xS2 nanoparticles


It has earlier been reported that that the gallium incorporation in wurtzite CuInS2 (CIS) results in structural distortion, non-homogeneous shape, and distribution of particles. However, a detailed study of the effect of Ga substitution on the structure and morphology has not been reported. Here, we report the synthesis of nanocrystalline CuInxGa1−xS2 (x = 1, 0.7, 0.5, 0.3, and 0) wurtzite particles by solution processing in a nitrogen atmosphere. Structural analyses by X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the as-synthesized CuInS2 (CIS) and CuGaS2 (CGS) nanoparticle were single-phase wurtzite structures, whereas CuIn0.7Ga0.3S2, CuIn0.5Ga0.5S2, and CuIn0.3Ga0.7S2 had three wurtzite phases having In-rich, In–Ga, and Ga-rich compositions. The shape of the resulting nanoparticles was either elongated, polygonal, or tadpole depending on the phase composition. In-rich particles had elongated rod-like morphology, the In–Ga particles were irregular hexagonal/equiaxed, while the Ga-rich phase formed with a tadpole morphology. The bandgap of the wurtzite-CuInxGa1−xS2 increased with Ga substitution: from 1.49 eV for CIS to 2.0 eV for CGS.

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  1. 1

    Reinhard P, Chirilǎ A, Blösch P, Pianezzi F, Nishiwaki S, Buecheler S, Tiwari AN (2013) Review of progress toward 20% efficiency flexible CIGS solar cells and manufacturing issues of solar modules. IEEE J Photovolt 3:572–580.

    Article  Google Scholar 

  2. 2

    Jackson P, Hariskos D, Lotter E, Paetel S, Wuerz R, Menner R, Wischmann W, Powalla M (2011) New world record efficiency for Cu(In, Ga)Se2 thin-film solar cells beyond 20%. Prog Photovol Res Appl 19:894–897.

    CAS  Article  Google Scholar 

  3. 3

    Ramanathan K, Contreras MA, Perkins CL, Asher S, Hasoon FS, Keane J, Young D, Romero M, Metzger W, Noufi R, Ward J, Duda A (2003) Properties of 19.2% efficiency ZnO/CdS/CuInGaSe2 thin-film solar cells. Prog Photovolt Res Appl 11:225–230.

    CAS  Article  Google Scholar 

  4. 4

    Green MA, Hishikawa Y, Dunlop ED, Levi DH, Hohl-Ebinger J, Ho-Baillie AWY (2018) Solar cell efficiency tables (version 51). Prog Photovolt Res Appl 26:3–12.

    Article  Google Scholar 

  5. 5

    Cui X, Yun D, Zhong C, Chen W, Cheng Q, Feng J, Zhang F (2015) A facile route for synthesis of CuInxGa1−xSe2 nanocrystals with tunable composition for photovoltaic application. J Sol Gel Sci Technol 76:469–475.

    CAS  Article  Google Scholar 

  6. 6

    Wang Y-HA, Zhang X, Bao N, Lin B, Gupta A (2011) Synthesis of shape-controlled monodisperse wurtzite CuInxGa1xS2 semiconductor nanocrystals with tunable band gap. J Am Chem Soc 133:11072–11075.

    CAS  Article  Google Scholar 

  7. 7

    Fischer J, Larsen JK, Guillot J, Aida Y, Eisenbarth T, Regesch D, Depredurand V, Fevre N, Siebentritt S, Dale PJ (2014) Composition dependent characterization of copper indium diselenide thin film solar cells synthesized from electrodeposited binary selenide precursor stacks. Sol Energy Mater Sol Cells 126:88–95.

    CAS  Article  Google Scholar 

  8. 8

    Rampino S, Armani N, Bissoli F, Bronzoni M, Calestani D, Calicchio M, Delmonte N, Gilioli E, Gombia E, Mosca R, Nasi L, Pattini F, Zappettini A, Mazzer M (2012) 15% efficient Cu(In, Ga)Se2 solar cells obtained by low-temperature pulsed electron deposition. Appl Phys Lett 101:132107.

    CAS  Article  Google Scholar 

  9. 9

    Nakada T, Paper I (2012) CIGS-based thin film solar cells and modules: unique material properties. Electron Mater Lett 8:179–185.

    CAS  Article  Google Scholar 

  10. 10

    Kapur V, Kemmerle R, Bansal A, Haber J, Schmitzberger J, Le P, Guevarra D, Kapur V, Stempien T (2008) Manufacturing of ‘ink based’ CIGS solar cells/modules. In 33rd IEEE photovoltaic specialists conference San Diego, CA, USA 2008 1 5

  11. 11

    Romeo A, Terheggen M, Abou-Ras D, Bätzner DL, Haug F-J, Kälin M, Rudmann D, Tiwari AN (2004) Development of thin-film Cu(In, Ga)Se2 and CdTe solar cells. Prog Photovolt Res Appl 12:93–111.

    CAS  Article  Google Scholar 

  12. 12

    Uhl AR, Katahara JK, Hillhouse HW (2016) Molecular-ink route to 13.0% efficient low-bandgap CuIn(S, Se)2 and 14.7% efficient Cu(In, Ga)(S, Se)2 solar cells. Energy Environ Sci 9:130–134.

    CAS  Article  Google Scholar 

  13. 13

    Bao N, Qiu X, Wang Y-HA, Zhou Z, Lu X, Grimes CA, Gupta A (2011) Facile thermolysis synthesis of CuInS2 nanocrystals with tunable anisotropic shape and structure. Chem Commun 47:9441–9443.

    CAS  Article  Google Scholar 

  14. 14

    Tinoco T, Rincón C, Quintero M, Pérez GS (1991) Phase diagram and optical energy gaps for CuInyGa1−ySe2 alloys. Phys Status Solidi 124:427–434.

    CAS  Article  Google Scholar 

  15. 15

    Loferski JJ (1956) Theoretical considerations governing the choice of the optimum semiconductor for photovoltaic solar energy conversion. J Appl Phys 27:777–784.

    CAS  Article  Google Scholar 

  16. 16

    Solar Frontier (2019) K.K Japan,

  17. 17

    Lindahl J, Zimmermann U, Szaniawski P, Torndahl T, Hultqvist A, Salomé P, Platzer-Björkman C, Edoff M (2013) Inline Cu(In, Ga)Se2 co-evaporation for high-efficiency solar cells and modules. IEEE J Photovolt 3:1100–1105.

    Article  Google Scholar 

  18. 18

    Huang C-H, Lin C-P, Jan Y-L (2016) Characteristics of (CIGS) photovoltaic devices co-evaporated with various Se flux rates at low temperatures. Semicond Sci Technol 31:85004.

    CAS  Article  Google Scholar 

  19. 19

    Ramanujam J, Singh UP (2017) Copper indium gallium selenide based solar cells—a review. Energy Environ Sci 10:1306–1319.

    CAS  Article  Google Scholar 

  20. 20

    Lee D-Y, Park S, Kim J (2011) Structural analysis of CIGS film prepared by chemical spray deposition. Curr Appl Phys 11:S88–S92.

    Article  Google Scholar 

  21. 21

    Guo Q, Ford GM, Hillhouse HW, Agrawal R (2009) Sulfide nanocrystal inks for dense Cu(In1−xGax)(S1−ySey)2 absorber films and their photovoltaic performance. Nano Lett 9:3060–3065.

    CAS  Article  Google Scholar 

  22. 22

    Arnou P, van Hest MFAM, Cooper CS, Malkov AV, Walls JM, Bowers JW (2016) Hydrazine free solution deposited CuIn(S, Se)2 solar Cells by spray deposition of metal chalcogenides. ACS Appl Mater Interfaces 8:11893–11897.

    CAS  Article  Google Scholar 

  23. 23

    Binsma JJM, Giling LJ, Bloem J (1980) Phase relations in the system Cu2S-In2S3. J Cryst Growth 50:429–436.

    CAS  Article  Google Scholar 

  24. 24

    Qi Y, Liu Q, Tang K, Liang Z, Ren Z, Liu X (2009) Synthesis and characterization of nanostructured wurtzite CuInS2: a new cation disordered polymorph of CuInS2. J Phys Chem C 113:3939–3944.

    CAS  Article  Google Scholar 

  25. 25

    Green MA, Emery K, Hishikawa Y, Warta W (2010) Solar cell efficiency tables (version 36). Prog Photovolt Res Appl 18:346–352.

    Article  Google Scholar 

  26. 26

    Norako ME, Brutchey RL (2010) Synthesis of metastable wurtzite CuInSe2 nanocrystals. Chem Mater 22:1613–1615.

    CAS  Article  Google Scholar 

  27. 27

    Norako ME, Franzman MA, Brutchey RL (2009) Growth kinetics of monodisperse Cu–In–S nanocrystals using a dialkyl disulfide sulfur source. Chem Mater 21:4299–4304.

    CAS  Article  Google Scholar 

  28. 28

    Batabyal SK, Tian L, Venkatram N, Ji W, Vittal JJ (2009) Phase-selective synthesis of CuInS2 nanocrystals. J Phys Chem C 113:15037–15042.

    CAS  Article  Google Scholar 

  29. 29

    Connor ST, Hsu C-M, Weil BD, Aloni S, Cui Y (2009) Phase transformation of biphasic Cu2S–CuInS2 to monophasic CuInS2 nanorods. J Am Chem Soc 131:4962–4966.

    CAS  Article  Google Scholar 

  30. 30

    Panthani MG, Akhavan V, Goodfellow B, Schmidtke JP, Dunn L, Dodabalapur A, Barbara PF, Korgel BA (2008) Synthesis of CuInS2, CuInSe2, and Cu(InxGa1-x)Se2 (CIGS) nanocrystal “inks” for printable photovoltaics. J Am Chem Soc 130:16770–16777.

    CAS  Article  Google Scholar 

  31. 31

    Nose K, Soma Y, Omata T, Otsuka-Yao-Matsuo S (2009) Synthesis of ternary CuInS2 nanocrystals; phase determination by complex ligand species. Chem Mater 21:2607–2613.

    CAS  Article  Google Scholar 

  32. 32

    Steinhagen C, Akhavan VA, Goodfellow BW, Panthani MG, Harris JT, Holmberg VC, Korgel BA (2011) Solution liquid solid synthesis of CuInSe2 nanowires and their implementation in photovoltaic devices. ACS Appl Mater Interfaces 3:1781–1785.

    CAS  Article  Google Scholar 

  33. 33

    Liu K, Li J, Xu Y, Shi L, Gao W (2018) Systematic investigation on synthesis of CuInS2 powder and its influencing factors. Cryst Res Technol 53:1700203.

    CAS  Article  Google Scholar 

  34. 34

    Pan D, An L, Sun Z, Hou W, Yang Y, Yang Z, Lu Y (2008) Synthesis of Cu–In–S ternary nanocrystals with tunable structure and composition. J Am Chem Soc 130:5620–5621.

    CAS  Article  Google Scholar 

  35. 35

    Liu H-X, Tang F-L, Xue H-T, Zhang Y, Cheng Y-W, Feng Y-D (2016) Lattice structures and electronic properties of wz-CuInS2/wz-CdS interface from first-principles calculations. Chin Phys B 25:123101.

    CAS  Article  Google Scholar 

  36. 36

    Zhang F, Sun C, Bajracharya C, Rodriguez RG, Pak JJ (2013) Fabrication and characterization of thin film solar cell made from CuIn0.75Ga0.25S2 wurtzite nanoparticles. J Nanomater.

    Article  Google Scholar 

  37. 37

    Ghorpade UV, Suryawanshi MP, Shin SW, Hong CW, Kim I, Moon JH, Yun JH, Kim JH, Kolekar SS (2015) Wurtzite CZTS nanocrystals and phase evolution to kesterite thin film for solar energy harvesting. Phys Chem Chem Phys 17:19777–19788.

    CAS  Article  Google Scholar 

  38. 38

    Mainz R, Singh A, Levcenko S, Klaus M, Genzel C, Ryan KM, Unold T (2014) Phase-transition-driven growth of compound semiconductor crystals from ordered metastable nanorods. Nat Commun 5:1–10.

    CAS  Article  Google Scholar 

  39. 39

    Liu X, Zhou F, Song N, Huang J, Yan C, Liu F, Sun K, Stride JA, Hao X, Green MA (2015) Exploring the application of metastable wurtzite nanocrystals in pure-sulfide Cu2ZnSnS4 solar cells by forming nearly micron-sized large grains. J Mater Chem A 3:23185–23193.

    CAS  Article  Google Scholar 

  40. 40

    Yang WC, Miskin CK, Hages CJ, Hanley EC, Handwerker C, Stach EA, Agrawal R (2014) Kesterite Cu2ZnSn(S, Se)4 absorbers converted from metastable, wurtzite-derived Cu2ZnSnS4 nanoparticles. Chem Mater 26:3530–3534.

    CAS  Article  Google Scholar 

  41. 41

    Zhou M, Gong Y, Xu J, Fang G, Xu Q, Dong J (2013) Colloidal CZTS nanoparticles and films: preparation and characterization. J Alloys Compd 574:272–277.

    CAS  Article  Google Scholar 

  42. 42

    Tan JMR, Lee YH, Pedireddy S, Baikie T, Ling XY, Wong LH (2014) Understanding the synthetic pathway of a single-phase quarternary semiconductor using surface-enhanced Raman scattering: a case of wurtzite Cu2ZnSnS4 nanoparticles. J Am Chem Soc 136:6684–6692.

    CAS  Article  Google Scholar 

  43. 43

    Jung HR, Shin SW, Gurav KV, Suryawanshi MP, Hong CW, Yang HS, Lee JY, Moon JH, Kim JH (2015) Phase evolution of Cu2ZnSnS4 (CZTS) kesterite thin films during the sulfurization process. Ceram Int 41:13006–13011.

    CAS  Article  Google Scholar 

  44. 44

    Tang A, Hu Z, Yin Z, Ye H, Yang C, Teng F (2015) One-pot synthesis of CuInS2 nanocrystals using different anions to engineer their morphology and crystal phase. Dalt Trans 44:9251–9259.

    CAS  Article  Google Scholar 

  45. 45

    Kruszynska M, Borchert H, Parisi J, Kolny-Olesiak J (2011) Investigations of solvents and various sulfur sources influence on the shape-controlled synthesis of CuInS2 nanocrystals. J Nanoparticle Res 13:5815–5824.

    CAS  Article  Google Scholar 

  46. 46

    Kruszynska M, Borchert H, Parisi J, Kolny-Olesiak J (2010) Synthesis and shape control of CuInS2 nanoparticles. J Am Chem Soc 132:15976–15986.

    CAS  Article  Google Scholar 

  47. 47

    Coughlan C, Singh A, Ryan KM (2013) Systematic study into the synthesis and shape development in colloidal CuInxGa1-xS2 nanocrystals. Chem Mater 25:653–661.

    CAS  Article  Google Scholar 

  48. 48

    Zhang X, Liu S, Wu F, Peng X, Yang B, Xiang Y (2018) Phase selective synthesis of CIGS nanoparticles with metastable phases through tuning solvent composition. Nanoscale Res Lett 13:362.

    CAS  Article  Google Scholar 

  49. 49

    Gusain M, Kumar P, Nagarajan R (2013) Wurtzite CuInS2: solution based one pot direct synthesis and its doping studies with non-magnetic Ga3+ and magnetic Fe3+ ions. RSC Adv 3:18863–18871.

    CAS  Article  Google Scholar 

  50. 50

    Gabka G, Leniarska K, Ostrowski A, Malinowska K, Donten M, Bujak P (2015) Solvent effect in the synthesis of Cu–In–S and Cu–In–Se nanocrystals with tunable structure and composition. Mater Chem Phys 162:291–298.

    CAS  Article  Google Scholar 

  51. 51

    Hao Z, Cui Y, Wang G (2015) Colloidal synthesis of wurtzite CuInS2 nanocrystals and their photovoltaic application. Mater Lett 146:77–80.

    CAS  Article  Google Scholar 

  52. 52

    Li Q, Zhai L, Zou C, Huang X, Zhang L, Yang Y, Chen X, Huang S (2013) Wurtzite CuInS2 and CuInxGa1−xS2 nanoribbons: synthesis, optical and photoelectrical properties. Nanoscale 5:1638.

    CAS  Article  Google Scholar 

  53. 53

    Lu X, Zhuang Z, Peng Q, Li Y (2011) Controlled synthesis of wurtzite CuInS2 nanocrystals and their side-by-side nanorod assemblies. Cryst Eng Comm 13:4039–4045.

    CAS  Article  Google Scholar 

  54. 54

    Gong F, Tian S, Liu B, Xiong D, Zhao X (2014) Oleic acid assisted formation mechanism of CuInS2 nanocrystals with tunable structures. RSC Adv 4:36875–36881.

    CAS  Article  Google Scholar 

  55. 55

    Kolny-Olesiak J, Weller H (2013) Synthesis and application of colloidal CuInS2 semiconductor nanocrystals. ACS Appl Mater Interfaces 5:12221–12237.

    CAS  Article  Google Scholar 

  56. 56

    Chang J, Waclawik ER (2013) Controlled synthesis of CuInS2, Cu2SnS3 and Cu2ZnSnS4 nano-structures: insight into the universal phase-selectivity mechanism. Cryst Eng Comm 15:5612–5619.

    CAS  Article  Google Scholar 

  57. 57

    Wu L, Chen SY, Fan FJ, Zhuang TT, Dai CM, Yu SH (2016) Polytypic nanocrystals of Cu-based ternary chalcogenides: colloidal synthesis and photoelectron chemical properties. J Am Chem Soc 138:5576–5584.

    CAS  Article  Google Scholar 

  58. 58

    Xie BB, Hu BB, Jiang LF, Li G, Du ZL (2015) The phase transformation of CuInS2 from chalcopyrite to wurtzite. Nanoscale Res Lett 10:86.

    CAS  Article  Google Scholar 

  59. 59

    Liu L, Li H, Liu Z, Xie YH (2018) Structure and band gap tunable CuInS2 nanocrystal synthesized by hot-injection method with altering the dose of oleylamine. Mater Des 149:145–152.

    CAS  Article  Google Scholar 

  60. 60

    Liu Z, Liu J, Huang Y, Li J, Yuan Y, Ye H, Zhu D, Wang Z, Tang A (2019) From one-dimensional to two-dimensional wurtzite CuGaS2 nanocrystals: non-injection synthesis and photocatalytic evolution. Nanoscale 11:158–169.

    CAS  Article  Google Scholar 

  61. 61

    Dilena E, Xie Y, Brescia R, Prato M, Maserati L, Krahne R, Paolella A, Bertoni G, Povia M, Moreels I, Manna L (2013) CuInxGa1–xS2 nanocrystals with tunable composition and band gap synthesized via a phosphine-free and scalable procedure. Chem Mater 25:3180–3187.

    CAS  Article  Google Scholar 

  62. 62

    Nelson JB, Riley DP (1945) An experimental investigation of extrapolation methods in the derivation of accurate unit-cell dimensions of crystals. Proc Phys Soc 57:160–177.

    CAS  Article  Google Scholar 

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The authors would like to thank the DST-SERB, New Delhi, for the financial support through grant sanction no. ECR/2016/000854. Authors would also like to thank DST for the FIST grant to establish the microscopy facility.


This study was funded by Department of Science and Technology-Science and Engineering Research Board (DST-SERB) (ECR/2016/000854).

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Pradeepkumar, M.S., Pal, A.S., Singh, A. et al. Phase separation in wurtzite CuInxGa1−xS2 nanoparticles. J Mater Sci 55, 11841–11855 (2020).

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