Journal of Sol-Gel Science and Technology

, Volume 88, Issue 2, pp 454–464 | Cite as

Influence of annealing temperature on material properties of red emitting ZnGa2O4: Cr3+ nanostructures

  • M. K. HussenEmail author
  • F. B. Dejene
Original Paper: Nano-structured materials (particles, fibers, colloids, composites, etc.)


Zinc gallate (ZnGa2O4) nanopowders doped with Cr3+ (1 mo%) were synthesized by the citric acid assisted sol–gel method. The influence of annealing temperature, structural, morphological, and optical properties of ZnGa2O4: Cr3+ (1 mol%) nanosized particles were investigated. The X-ray diffraction (XRD) spectra indicated that the nanoparticles are cubic in structure and the annealing temperature did not influence any c in structure. The average crystallite size of ZnGa2O4: Cr3+ nanoparticles were observed to increase from 11.85 to 30.88 nm as the annealing temperature increased from 600 to 1000 °C. The scanning electron microscopy (SEM) showed nearly spherical nanostructures that change in size with annealing temperature. The high resolution transmission electron microscope (HR-TEM) images show well resolved lattice fringes which is an indications of highly crystalline samples. Ultraviolet–visible (UV–Vis) measurement show decrease in reflectance in visible region and energy band gap was found to decrease with annealing temperature. The photoluminescence (PL) intensity was found to be maximum for sample annealed at high temperature (1000 °C) and least with sample annealed at low temperature (600 °C). An increase in annealing temperature leads significantly increment in PL intensity. The degree of crystallinity also increased with annealing temperature from XRD, SEM, and HR-TEM analysis. The photoluminescence lifetimes, particle size, and emission spectra are comparable with reports on bioimaging applications.


In this paper, we provide the insights on the “Influence of annealing temperature on material properties of red emitting ZnGa2O4: Cr3+ nanostructures”.

It is found that:

  • The structural, morphological and optical properties of this material affected by annealing temperature.

  • The crystallite size and PL intensity found to be increased with annealing temperature.

  • Energy band gap found to be decreased with annealing temperature.

  • The parameter values obtained encourage the application of this materials for bioimaging application.


Sol Gel Annealing temperature ZnGa2O4 Bioimaging Citric acid 



The authors would like to acknowledge the financial support given from the directorate of the research at University of the Free State South Africa.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Cha JH, Kim KH, Park YS, Park SJ, Choi HW (2009) Photoluminescence characteristics of nanocrystalline ZnGa2O4 phosphors obtained at different sintering temperatures. Mol Cryst Liq Cryst 499(1):85–407CrossRefGoogle Scholar
  2. 2.
    Kim JS, Kim JS, Kim TW, Park HL, Kim YG, Chang SK, Do Han S (2004) Energy transfer among three luminescent centers in full-color emitting ZnGa2O4: Mn2+, Cr3+ phosphors. Solid State Commun 131(8):493–7CrossRefGoogle Scholar
  3. 3.
    Luan T, Liu J, Yuan X, Li JG (2017) Controlled hydrothermal synthesis and photoluminescence of nanocrystalline ZnGa2O4: Cr 3+ monospheres. Nanoscale Res Lett 12(1):219CrossRefGoogle Scholar
  4. 4.
    Bordun OM, Bihday VG, Kukharskyy IY (2014) Photo-and cathodoluminescence of ZnGa2O4: Cr thin films. J Appl Spectrosc 81(1):43–8CrossRefGoogle Scholar
  5. 5.
    Sharma SK, Gourier D, Viana B, Maldiney T, Teston E, Scherman D, Richard C (2014) Persistent luminescence of AB2O4: Cr3+ (A = Zn, Mg, B = Ga, Al) spinels: new biomarkers for in vivo imaging. Opt Mater 36(11):1901–6CrossRefGoogle Scholar
  6. 6.
    Srivastava BB, Kuang A, Mao Y (2015) Persistent luminescent sub-10 nm Cr doped ZnGa2O4 nanoparticles by a biphasic synthesis route. Chem Commun 51(34):7372–5CrossRefGoogle Scholar
  7. 7.
    Gu Z, Liu F, Li X, Howe JY, Xu J, Pan Z (2009) Red, green, and blue (RGB) luminescence from ZnGa2O4 nanowire arrays J Am Chem Soc 1(1):354–357Google Scholar
  8. 8.
    Bessière A, Jacquart S, Priolkar K, Lecointre A, Viana B, Gourier D (2011) ZnGa2O4: Cr3+: a new red long-lasting phosphor with high brightness. Opt Express 19(11):10131–7CrossRefGoogle Scholar
  9. 9.
    Dhak P, Gayen UK, Mishra S, Pramanik P, Roy A (2009) Optical emission spectra of chromium doped nanocrystalline zinc gallate. J Appl Phys 106(6):063721CrossRefGoogle Scholar
  10. 10.
    Cha JH, Choi HW (2011) Luminescence characteristics of ZnGa2O4: Mn2+, Cr3+ phosphor and thick film. Trans Electr Electron Mater 12(1):11–5CrossRefGoogle Scholar
  11. 11.
    Sharma SK, Gourier D, Viana B, Maldiney T, Teston E, Scherman D, Richard C (2014) Persistent luminescence of AB2O4: Cr3+ (A = Zn, Mg, B = Ga, Al) spinels: new biomarkers for in vivo imaging. Opt Mater 36(11):1901–6CrossRefGoogle Scholar
  12. 12.
    de Chermont QL, Chanéac C, Seguin J, Pellé F, Maîtrejean S, Jolivet JP, Gourier D, Bessodes M, Scherman D (2007) Nanoprobes with near-infrared persistent luminescence for in vivo imaging. NAS 104(22):9266–71CrossRefGoogle Scholar
  13. 13.
    Su J, Ye S, Yi X, Lu FQ, Yang XB, Zhang QY (2017) Influence of oxygen vacancy on persistent luminescence in ZnGa2O4: Cr 3+ and identification of electron carriers. Opt Mater Express 7(3):734–43CrossRefGoogle Scholar
  14. 14.
    Singh SK (2014) Red and near infrared persistent luminescence nano-probes for bioimaging and targeting applications. RSC Adv 4(102):58674–98CrossRefGoogle Scholar
  15. 15.
    Motloung SV, Tsega M, Dejene FB, Swart HC, Ntwaeaborwa OM, Koao LF, Motaung TE, Hato MJ (2016) Effect of annealing temperature on structural and optical properties of ZnAl2O4: 1.5% Pb2+ nanocrystals synthesized via sol–gel reaction. J Alloy Compd 677:72–9CrossRefGoogle Scholar
  16. 16.
    Menon SG, Hebbar DN, Kulkarni SD, Choudhari KS, Santhosh C (2017) Facile synthesis and luminescence studies of nanocrystalline red emitting Cr: ZnAl2O4 phosphor. Mater Res Bull 86:63–71CrossRefGoogle Scholar
  17. 17.
    Malevu TD, Ocaya RO (2015) Effect of annealing temperature on structural, morphology and optical properties of ZnO nano-needles prepared by zinc-air cell system method. Int J Electrochem Sci 10:1752–61Google Scholar
  18. 18.
    Williamson G, Smallman R (1956) Influences of substrate temperature on microcrystalline structure and optical properties of ZnTe thin films. Philos Mag 34:46Google Scholar
  19. 19.
    Guneri E, Gode F, Ulutas C, Kirmizigul F, Altindemir G (2010) Chalco Lett 7:685Google Scholar
  20. 20.
    Rahul Kumar B, Patel, Phil M (2010) Dissertation Submitted to Sardar Patel UniversityGoogle Scholar
  21. 21.
    Ivanova T, Harizanova A, Koutzarova T, Vertruyen B (2015) Optical characterization of sol–gel ZnO: Al thin films. Super Lattices Microstruct 85:101–11CrossRefGoogle Scholar
  22. 22.
    Jule LT, Dejene FB, Roro KT, Urgessa ZN, Botha JR (2016) Rapid synthesis of blue emitting ZnO nanoparticles for fluorescent applications. Phys B 497:71–7CrossRefGoogle Scholar
  23. 23.
    Safa S, Azimirad R, Safalou Moghaddam S, Rabbani M (2016) Investigating on photo catalytic performance of CuO micro and nanostructures prepared by different precursors. Desalin Water Treat 57(15):6723–31CrossRefGoogle Scholar
  24. 24.
    Somasundaram K, Abhilash KP, Sudarsan V, Selvin PC, Kadam RM (2016) Defect luminescence and lattice strain in Mn2+ doped ZnGa2O4. Phys B 491:79–83CrossRefGoogle Scholar
  25. 25.
    Safa S, Mokhtari S, Khayatian A, Azimirad R (2018) Improving ultraviolet photodetection of ZnO nanorods by Cr doped ZnO encapsulation process. Opt Commun 413:131–5CrossRefGoogle Scholar
  26. 26.
    Wang L, Hou Z, Quan Z, Lian H, Yang P, Lin J (2009) Preparation and luminescence properties of Mn2+ doped ZnGa2O4 nanofibers via electrospinning process. Mater Res 44(10):1978–83Google Scholar
  27. 27.
    Luan T, Liu J, Yuan X, Li JG (2017) Controlled hydrothermal synthesis and photoluminescence of nanocrystalline ZnGa2O4: Cr3+ monospheres. Nanoscale Res Lett 12(1):219CrossRefGoogle Scholar
  28. 28.
    Sangeetha A, Kumar KV, Kumar GN (2017) Effect of annealing temperature on the structural and magnetic properties of NiFe2O4 nanoferrites. Adv Mater Phys Chem 7(02):19CrossRefGoogle Scholar
  29. 29.
    Zou L, Xiang X, Wei M, Li F, Evans DG (2008) Single-crystalline ZnGa2O4 spinel phosphor via a single-source inorganic precursor route. Inorg Chem 47(4):1361–9CrossRefGoogle Scholar
  30. 30.
    Motloung SV, Dejene FB, Ntwaeaborwa OM, Swart HC (2014) Effects of catalyst/zinc mole fraction on ZnAl2O4: 0.01% Cr3+ nanocrystals synthesized using sol–gel process. Mater Res Express 1(4):045029CrossRefGoogle Scholar
  31. 31.
    Motloung SV, Dejene FB, Koao LF, Ntwaeaborwa OM, Swart HC, Motaung TE, Ndwandwe OM (2017) Structural and optical studies of ZnAl2O4: x% Cu2+ (0 < x ≤ 1.25) nanophosphors synthesized via citrate sol–gel route. Opt Mater 64:26–32CrossRefGoogle Scholar
  32. 32.
    Motloung SV, Dejene FB, Swart HC, Ntwaeaborwa OM (2015) Effects of Cr3+ mol% on the structure and optical properties of the ZnAl2O4: Cr3+ nanocrystals synthesized using sol–gel process. Ceram Int 41(5):6776–83CrossRefGoogle Scholar
  33. 33.
    Menon SG, Choudhari KS, Shivashankar SA, Santhosh C, Kulkarni SD (2017) Rapid annealing: A novel processing technique for Cr: ZnAl2O4 nanoparticles. J Alloy Compd 728:484–9CrossRefGoogle Scholar
  34. 34.
    Hone FG, Dejene FB (2017) Tuning the optical band gap and stoichiometric ratio of chemically synthesized lead selenide thin films by controlling film thickness. J Mater Sci Mater Electron 28(8):5979–89CrossRefGoogle Scholar
  35. 35.
    Bouhssira N, Abed S, Tomasella E, Cellier J, Mosbah A, Aida MS, Jacquet M (2006) Influence of annealing temperature on the properties of ZnO thin films deposited by thermal evaporation. Appl Surf Sci 252(15):5594–7CrossRefGoogle Scholar
  36. 36.
    Zhang W, Zhang J, Li Y, Chen Z, Wang T (2010) Preparation and optical properties of ZnGa2O4: Cr3+ thin films derived by sol–gel process. Appl Surf Sci 256(14):4702–7CrossRefGoogle Scholar
  37. 37.
    Tshabalala KG, Cho SH, Park JK, Pitale SS, Nagpure IM, Kroon RE, Swart HC, Ntwaeaborwa OM (2011) Luminescent properties and X-ray photoelectron spectroscopy study of ZnAl2O4: Ce3+, Tb3+ phosphor. J Alloys Compd 509(41):10115–20CrossRefGoogle Scholar
  38. 38.
    Hussen MK, Dejene FB, Gonfa GG (2018) Effect of citric acid on material properties of ZnGa2O4:Cr3+ nanopowder prepared by sol–gel method. Appl Phys A Mater Sci Process 124:1–10CrossRefGoogle Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of PhysicsUniversity of the Free State (Qwaqwa Campus)PhuthaditjhabaSouth Africa

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