Enhancement of red emission assigned to inversion defects in ZnAl₂O₄:Cr³⁺ hollow spheres

Abstract

ZnAl₂O₄:Cr³⁺ hollow spheres composed of secondary nanoparticles with single spinel phase were fabricated using carbon templets. Monitoring the emission of 687 nm, two wide excitation bands attributed to the electrons of Cr³⁺ transiting from ⁴A_2g (⁴F) → ⁴T_1g (⁴F) and ⁴A_2g (⁴F) → ⁴T_2g (⁴F) were observed. The broad excitation band at about 397 nm was asymmetric and consisted of two peaks, indicating that there was a trigonal distortion existing in the lattices. The intensity of all emitting peaks revealed sharp increasing trend with the sintering temperature increase, and the intensity of emission at 698 nm assigned to inversion defects was more intense than that of emission at 687 nm assigned to octahedral Cr³⁺ ions in the undistorted spinel lattice. The samples with higher synthesized temperature revealed longer decay time, and the relative weightage of shorter decay time component decreased with the increase of sintering temperature, indicating that the surface defects decreased.

Keywords

semiconductors / hollow sphere / inversion defects / photoluminescence

References

[1] Cheng B C, Ouyang Z Y, Tian B X, . Porous ZnAl₂O₄ spinel nanorods: High sensitivity humidity sensors. Ceramics International, 2013, 39(7): 7379–7386

[2] Bite I, Krieke G, Zolotarjovs A, . Novel method of phosphorescent strontium aluminate coating preparation on aluminum. Materials & Design, 2018, 160: 794–802

[3] Pathak N, Ghosh P S, Saxena S, . Exploring defect-induced emission in ZnAl₂O₄: An exceptional color-tunable phosphor material with diverse lifetimes. Inorganic Chemistry, 2018, 57(7): 3963–3982

[4] Jain M, Manju , Gundimeda A, . Defect induced broadband visible to near-infrared luminescence in ZnAl₂O₄ nanocrystals. Applied Surface Science, 2019, 480: 945–950

[5] Zhang D, Yin Y L, Liu Y L, . The photoluminescence and magnetic properties of ZnAl₂O₄:Mn nanocrystals. Journal of Physics and Chemistry of Solids, 2013, 74(8): 1131–1135

[6] Zhang D, Ma X X, Zhang Q, . Influence of Zn/Al molar ratio on the structural and photoluminescence performances of Zn_xAl₂O₄:Cr³⁺ phosphors. Journal of Alloys and Compounds, 2016, 688: 581–587

[7] Xiang C, Tan H L, Lu J S, . Effect of O₂ on reduction of NO₂ with CH₄ over gallium-modified ZnAl₂O₄ spinel-oxide catalyst by first principle analysis. Applied Surface Science, 2015, 349: 138–146

[8] Walerczyk W, Zawadzki M, Okal J. Characterization of the metallic phase in nanocrystalline ZnAl₂O₄-supported Pt catalysts. Applied Surface Science, 2011, 257(6): 2394–2400

[9] Shi Q, Wang C, Zhang D, . Luminescence of Cr³⁺-doped ZnGa₂O₄ thin films deposited by pulsed laser ablation. Thin Solid Films, 2012, 520(23): 6845–6849

[10] Sreeja V, Smitha T S, Nand D, . Size dependence coordination behavior and cation distribution in MgAl₂O₄ nanoparicles from ²⁷Al solid state NMR studies. The Journal of Physical Chemistry C, 2008, 112(38): 14737–14744 doi:10.1021/jp800412k

[11] Yang C G, Zhu W D, Sen S, . Site inversion induces thermodynamic stability against coarsening in zinc aluminate spinel. The Journal of Physical Chemistry C, 2019, 123(14): 8818–8826

[12] Lahmer M A. First-principles study of the structural and electronic properties of the clean and O-deficient ZnAl₂O₄ (111) surfaces. Surface Science, 2019, 682: 75–83

[13] Chen M G, Liu Q, Zhu J F, . Effect of ZnAl₂O₄ content on the microstructure and electrical properties of ZnO-based compound conductive ceramics. Journal of Alloys and Compounds, 2018, 750: 213–219

[14] Zhang Y J, Liu M, Peng B, . Temperature induced interface and optical properties of the multi-layer nanotube network. Journal of Applied Physics, 2018, 123(22): 224102

[15] Zhang D, Guo Q J, Ren Y F, . Influence of inversion defects and Cr‒Cr pairs on the photoluminescent performance of ZnAl₂O₄ crystals. Journal of Sol-Gel Science and Technology, 2018, 85(1): 121–131

[16] Zhou A P, Zhang D, Gong Z Q, . The structure and photoluminescence performances of Zn_xAl₂O₄:Cr³⁺ crystals with various annealing temperatures. Optoelectronics and Advanced Materials Rapid Communications, 2018, 12(9‒10): 588–594

[17] Zhang D, Du C Y, Chen J X, . Improvement of structural and optical properties of ZnAl₂O₄:Cr³⁺ ceramics with surface modification by using various concentrations of zinc acetate. Journal of Sol-Gel Science and Technology, 2018, 88(2): 422–429

[18] Singh V, Chakradhar R P S, Rao J L, . EPR and photoluminescence properties of combustion-synthesized Zn_xAl₂O₄:Cr³⁺ phosphors. Journal of Materials Science, 2011, 46(7): 2331–2337

[19] Zhang D, Qiu Y H, Xie Y R, . The improvement of structure and photoluminescence properties of Zn_xAl₂O₄:Cr³⁺ ceramics synthesized by using solvothermal method. Materials & Design, 2017, 115: 37–45

[20] Dong G, Xiao X, Peng M, . Synthesis and optical properties of chromium-doped spinel hollow nanofibers by single-nozzle electrospinning. RSC Advances, 2012, 2(7): 2773–2782

[21] Hebbar D N, Menon S G, Choudhari K S, . Cr-doped ZnAl₂O₄: Microwave solution route for ceramic nanoparticles from metal organic complexes in minutes. Journal of the American Ceramic Society, 2018, 101(2): 800–811

[22] Karthik H G S, Menon S G, Hebbar N D, . Nanocrystalline MgCr_xAl_2−xO₄: Facile synthesis and thermal dependency of photoluminescence. Materials Research Bulletin, 2017, 94: 513–519

[23] Gluchowski P, Strek W. Luminescence and excitation spectra of Cr³⁺:MgAl₂O₄ nanoceramics. Materials Chemistry and Physics, 2013, 140(1): 222–227

[24] Karthik H G S, Menon S G, Hebbar N D, . Effect of Zn substitution in Cr³⁺ doped MgAl₂O₄ mixed spinel nanoparticles on red/NIR emission properties. Materials Research Bulletin, 2019, 111: 294–300

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