Effect of Zn substitution in Cr3+ doped MgAl2O4 mixed spinel nanoparticles on red/NIR emission properties

Shreekrishna Karthik H.G., Samvit G. Menon, Deepak Hebbar N., K. S. Choudhari, C. Santhosh, Suresh D. Kulkarni

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Red/Near-infrared (NIR) emitting Mg1-xZnxAl1.98Cr0.02O4 nanoparticles were synthesized by co-precipitation followed by firing(1200 °C). Gradual shift of XRD peaks with Zn-content confirmed complete solid-solution formation. HRTEM revealed hexagonal sheet-like structures and lattice fringes revealed their single-crystallinity. Owing to refractory nature of MgAl2O4, particles were smaller(∼38 nm) in Mg-rich samples and gradually increased(∼58 nm) with Zn-substitution. Due to trigonal distortion, the fine splitting of the 4T1g level of Cr3+ manifests as asymmetric band(400 nm) in the excitation spectrum. Cr3+ emission was clearly observed, comprising of R-line and multi-phonon side-bands on either side, with maximum R-line intensity for x = 0.5. With increasing x, side-bands were more pronounced probably due to the band-gap difference of end members. High Dq/B (3.5–3.9), suggested Cr3+ in a strong crystal-field. Racah-parameter(B) variations suggest increased electron delocalization over molecular orbitals for higher Mg2+ substitutions. Longer lifetimes (23–34 ms) are well-suited for bioimaging and optoelectronic applications. Such a simple synthesis can be easily extended to other important phosphors.

Original languageEnglish
Pages (from-to)294-300
Number of pages7
JournalMaterials Research Bulletin
Volume111
DOIs
Publication statusPublished - 01-03-2019

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spinel
Substitution reactions
substitutes
Nanoparticles
Infrared radiation
nanoparticles
Molecular orbitals
Coprecipitation
Optoelectronic devices
Refractory materials
Phosphors
Solid solutions
Energy gap
Crystals
Electrons
refractories
phosphors
crystal field theory
crystallinity
molecular orbitals

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

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title = "Effect of Zn substitution in Cr3+ doped MgAl2O4 mixed spinel nanoparticles on red/NIR emission properties",
abstract = "Red/Near-infrared (NIR) emitting Mg1-xZnxAl1.98Cr0.02O4 nanoparticles were synthesized by co-precipitation followed by firing(1200 °C). Gradual shift of XRD peaks with Zn-content confirmed complete solid-solution formation. HRTEM revealed hexagonal sheet-like structures and lattice fringes revealed their single-crystallinity. Owing to refractory nature of MgAl2O4, particles were smaller(∼38 nm) in Mg-rich samples and gradually increased(∼58 nm) with Zn-substitution. Due to trigonal distortion, the fine splitting of the 4T1g level of Cr3+ manifests as asymmetric band(400 nm) in the excitation spectrum. Cr3+ emission was clearly observed, comprising of R-line and multi-phonon side-bands on either side, with maximum R-line intensity for x = 0.5. With increasing x, side-bands were more pronounced probably due to the band-gap difference of end members. High Dq/B (3.5–3.9), suggested Cr3+ in a strong crystal-field. Racah-parameter(B) variations suggest increased electron delocalization over molecular orbitals for higher Mg2+ substitutions. Longer lifetimes (23–34 ms) are well-suited for bioimaging and optoelectronic applications. Such a simple synthesis can be easily extended to other important phosphors.",
author = "{Karthik H.G.}, Shreekrishna and Menon, {Samvit G.} and {Hebbar N.}, Deepak and Choudhari, {K. S.} and C. Santhosh and Kulkarni, {Suresh D.}",
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Effect of Zn substitution in Cr3+ doped MgAl2O4 mixed spinel nanoparticles on red/NIR emission properties. / Karthik H.G., Shreekrishna; Menon, Samvit G.; Hebbar N., Deepak; Choudhari, K. S.; Santhosh, C.; Kulkarni, Suresh D.

In: Materials Research Bulletin, Vol. 111, 01.03.2019, p. 294-300.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of Zn substitution in Cr3+ doped MgAl2O4 mixed spinel nanoparticles on red/NIR emission properties

AU - Karthik H.G., Shreekrishna

AU - Menon, Samvit G.

AU - Hebbar N., Deepak

AU - Choudhari, K. S.

AU - Santhosh, C.

AU - Kulkarni, Suresh D.

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Red/Near-infrared (NIR) emitting Mg1-xZnxAl1.98Cr0.02O4 nanoparticles were synthesized by co-precipitation followed by firing(1200 °C). Gradual shift of XRD peaks with Zn-content confirmed complete solid-solution formation. HRTEM revealed hexagonal sheet-like structures and lattice fringes revealed their single-crystallinity. Owing to refractory nature of MgAl2O4, particles were smaller(∼38 nm) in Mg-rich samples and gradually increased(∼58 nm) with Zn-substitution. Due to trigonal distortion, the fine splitting of the 4T1g level of Cr3+ manifests as asymmetric band(400 nm) in the excitation spectrum. Cr3+ emission was clearly observed, comprising of R-line and multi-phonon side-bands on either side, with maximum R-line intensity for x = 0.5. With increasing x, side-bands were more pronounced probably due to the band-gap difference of end members. High Dq/B (3.5–3.9), suggested Cr3+ in a strong crystal-field. Racah-parameter(B) variations suggest increased electron delocalization over molecular orbitals for higher Mg2+ substitutions. Longer lifetimes (23–34 ms) are well-suited for bioimaging and optoelectronic applications. Such a simple synthesis can be easily extended to other important phosphors.

AB - Red/Near-infrared (NIR) emitting Mg1-xZnxAl1.98Cr0.02O4 nanoparticles were synthesized by co-precipitation followed by firing(1200 °C). Gradual shift of XRD peaks with Zn-content confirmed complete solid-solution formation. HRTEM revealed hexagonal sheet-like structures and lattice fringes revealed their single-crystallinity. Owing to refractory nature of MgAl2O4, particles were smaller(∼38 nm) in Mg-rich samples and gradually increased(∼58 nm) with Zn-substitution. Due to trigonal distortion, the fine splitting of the 4T1g level of Cr3+ manifests as asymmetric band(400 nm) in the excitation spectrum. Cr3+ emission was clearly observed, comprising of R-line and multi-phonon side-bands on either side, with maximum R-line intensity for x = 0.5. With increasing x, side-bands were more pronounced probably due to the band-gap difference of end members. High Dq/B (3.5–3.9), suggested Cr3+ in a strong crystal-field. Racah-parameter(B) variations suggest increased electron delocalization over molecular orbitals for higher Mg2+ substitutions. Longer lifetimes (23–34 ms) are well-suited for bioimaging and optoelectronic applications. Such a simple synthesis can be easily extended to other important phosphors.

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