Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl                         2                         O                         4                          /ZnO/SrAl                         2                         O                         4                         /Sr                         3                         Al                         2                         O                         6                         :0.025% Tb                         3+                          nanophosphor synthesized by sol-gel technique

Motlalepula Rebecca Mhlongo; L. F. Koao; R. E. Kroon; T. E. Motaung; Setumo Victor Motloung

doi:10.1016/j.molstruc.2019.02.021

Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique

Motlalepula Rebecca Mhlongo^*, L. F. Koao, R. E. Kroon, T. E. Motaung, Setumo Victor Motloung

^*Corresponding author for this work

Physics

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Abstract

Nanophosphor powders of the mixed phases of ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ (ZZSS) doped with Tb ³⁺ (ZZSS:0.025%Tb ³⁺ ) were successfully prepared by sol-gel technique. The effect of the annealing period at a fixed annealing temperature (1000 °C) and dopant concentration (0.025% Tb ³⁺ ) on the structure and photoluminescence properties was investigated. X-ray diffraction results revealed that the crystallite size was influenced by the annealing period. Scanning electron microscopy showed that varying the annealing period influenced the particle morphology of the prepared nanophosphor material. High resolution transmission electron microscopy confirmed that the prepared material is on the nanoscale. The photoluminescence results showed that the ZZSS emits at 585 nm when excited at 374 nm, which is attributed to the defects centres within the ZnO phase. The Tb ³⁺ doped samples showed emissions peaks at 545, 590 and 623 nm which were attributed to the 4f transitions of Tb ³⁺ , specifically ⁵ D ₄ → ⁷ F _J (J = 5, 4, 3). Increasing the annealing period up to 5.4 h led to luminescence enhancements, while a further increase led to quenching. The Commision Internationale de l'Eclairage coordinates showed that the greenish emission colour could be tuned by varying the annealing period.

Original language	English
Pages (from-to)	92-101
Number of pages	10
Journal	Journal of Molecular Structure
Volume	1184
DOIs	https://doi.org/10.1016/j.molstruc.2019.02.021 https://doi.org/10.1016/j.molstruc.2019.02.021
Publication status	Published - 15 May 2019

Keywords

Annealing period
Luminescence
Mixed phases
Sol-gel
Tb

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Mhlongo, M. R., Koao, L. F., Kroon, R. E., Motaung, T. E., & Motloung, S. V. (2019). Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique Journal of Molecular Structure, 1184, 92-101. https://doi.org/10.1016/j.molstruc.2019.02.021, https://doi.org/10.1016/j.molstruc.2019.02.021

Mhlongo, Motlalepula Rebecca ; Koao, L. F. ; Kroon, R. E. et al. / Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique In: Journal of Molecular Structure. 2019 ; Vol. 1184. pp. 92-101.

@article{454f267f6b9c4d2d867b234e05e0057a,

title = " Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl 2 O 4 /ZnO/SrAl 2 O 4 /Sr 3 Al 2 O 6 :0.025% Tb 3+ nanophosphor synthesized by sol-gel technique ",

abstract = " Nanophosphor powders of the mixed phases of ZnAl 2 O 4 /ZnO/SrAl 2 O 4 /Sr 3 Al 2 O 6 (ZZSS) doped with Tb 3+ (ZZSS:0.025%Tb 3+ ) were successfully prepared by sol-gel technique. The effect of the annealing period at a fixed annealing temperature (1000 °C) and dopant concentration (0.025% Tb 3+ ) on the structure and photoluminescence properties was investigated. X-ray diffraction results revealed that the crystallite size was influenced by the annealing period. Scanning electron microscopy showed that varying the annealing period influenced the particle morphology of the prepared nanophosphor material. High resolution transmission electron microscopy confirmed that the prepared material is on the nanoscale. The photoluminescence results showed that the ZZSS emits at 585 nm when excited at 374 nm, which is attributed to the defects centres within the ZnO phase. The Tb 3+ doped samples showed emissions peaks at 545, 590 and 623 nm which were attributed to the 4f transitions of Tb 3+ , specifically 5 D 4 → 7 F J (J = 5, 4, 3). Increasing the annealing period up to 5.4 h led to luminescence enhancements, while a further increase led to quenching. The Commision Internationale de l'Eclairage coordinates showed that the greenish emission colour could be tuned by varying the annealing period. ",

keywords = "Annealing period, Luminescence, Mixed phases, Sol-gel, Tb",

author = "Mhlongo, {Motlalepula Rebecca} and Koao, {L. F.} and Kroon, {R. E.} and Motaung, {T. E.} and Motloung, {Setumo Victor}",

note = "Funding Information: This work is supported by the South African National Research Foundation (NRF) Thuthuka programme (fund number: UID 99266 and 113947 ), Sefako Makgatho Health Science University (SMU) Research Development Grant (RDG). This work is based on the research supported in part by the National Research Foundation of South Africa (R.E. Kroon, Grant Number 93214 ). The author would like to thank Dr James Wesley-Smith and SMU Electron Microscope Unit for all SEM and TEM images. Appendix A Publisher Copyright: {\textcopyright} 2019 Elsevier B.V. Copyright: Copyright 2019 Elsevier B.V., All rights reserved.",

year = "2019",

month = may,

day = "15",

doi = "10.1016/j.molstruc.2019.02.021",

language = "English",

volume = "1184",

pages = "92--101",

journal = "Journal of Molecular Structure",

issn = "0022-2860",

publisher = "Elsevier",

}

Mhlongo, MR, Koao, LF, Kroon, RE, Motaung, TE & Motloung, SV 2019, ' Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique ', Journal of Molecular Structure, vol. 1184, pp. 92-101. https://doi.org/10.1016/j.molstruc.2019.02.021, https://doi.org/10.1016/j.molstruc.2019.02.021

Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique . / Mhlongo, Motlalepula Rebecca; Koao, L. F.; Kroon, R. E. et al.
In: Journal of Molecular Structure, Vol. 1184, 15.05.2019, p. 92-101.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl 2 O 4 /ZnO/SrAl 2 O 4 /Sr 3 Al 2 O 6 :0.025% Tb 3+ nanophosphor synthesized by sol-gel technique

AU - Mhlongo, Motlalepula Rebecca

AU - Koao, L. F.

AU - Kroon, R. E.

AU - Motaung, T. E.

AU - Motloung, Setumo Victor

N1 - Funding Information: This work is supported by the South African National Research Foundation (NRF) Thuthuka programme (fund number: UID 99266 and 113947 ), Sefako Makgatho Health Science University (SMU) Research Development Grant (RDG). This work is based on the research supported in part by the National Research Foundation of South Africa (R.E. Kroon, Grant Number 93214 ). The author would like to thank Dr James Wesley-Smith and SMU Electron Microscope Unit for all SEM and TEM images. Appendix A Publisher Copyright: © 2019 Elsevier B.V. Copyright: Copyright 2019 Elsevier B.V., All rights reserved.

PY - 2019/5/15

Y1 - 2019/5/15

N2 - Nanophosphor powders of the mixed phases of ZnAl 2 O 4 /ZnO/SrAl 2 O 4 /Sr 3 Al 2 O 6 (ZZSS) doped with Tb 3+ (ZZSS:0.025%Tb 3+ ) were successfully prepared by sol-gel technique. The effect of the annealing period at a fixed annealing temperature (1000 °C) and dopant concentration (0.025% Tb 3+ ) on the structure and photoluminescence properties was investigated. X-ray diffraction results revealed that the crystallite size was influenced by the annealing period. Scanning electron microscopy showed that varying the annealing period influenced the particle morphology of the prepared nanophosphor material. High resolution transmission electron microscopy confirmed that the prepared material is on the nanoscale. The photoluminescence results showed that the ZZSS emits at 585 nm when excited at 374 nm, which is attributed to the defects centres within the ZnO phase. The Tb 3+ doped samples showed emissions peaks at 545, 590 and 623 nm which were attributed to the 4f transitions of Tb 3+ , specifically 5 D 4 → 7 F J (J = 5, 4, 3). Increasing the annealing period up to 5.4 h led to luminescence enhancements, while a further increase led to quenching. The Commision Internationale de l'Eclairage coordinates showed that the greenish emission colour could be tuned by varying the annealing period.

AB - Nanophosphor powders of the mixed phases of ZnAl 2 O 4 /ZnO/SrAl 2 O 4 /Sr 3 Al 2 O 6 (ZZSS) doped with Tb 3+ (ZZSS:0.025%Tb 3+ ) were successfully prepared by sol-gel technique. The effect of the annealing period at a fixed annealing temperature (1000 °C) and dopant concentration (0.025% Tb 3+ ) on the structure and photoluminescence properties was investigated. X-ray diffraction results revealed that the crystallite size was influenced by the annealing period. Scanning electron microscopy showed that varying the annealing period influenced the particle morphology of the prepared nanophosphor material. High resolution transmission electron microscopy confirmed that the prepared material is on the nanoscale. The photoluminescence results showed that the ZZSS emits at 585 nm when excited at 374 nm, which is attributed to the defects centres within the ZnO phase. The Tb 3+ doped samples showed emissions peaks at 545, 590 and 623 nm which were attributed to the 4f transitions of Tb 3+ , specifically 5 D 4 → 7 F J (J = 5, 4, 3). Increasing the annealing period up to 5.4 h led to luminescence enhancements, while a further increase led to quenching. The Commision Internationale de l'Eclairage coordinates showed that the greenish emission colour could be tuned by varying the annealing period.

KW - Annealing period

KW - Luminescence

KW - Mixed phases

KW - Sol-gel

KW - Tb

UR - http://www.scopus.com/inward/record.url?scp=85061672724&partnerID=8YFLogxK

U2 - 10.1016/j.molstruc.2019.02.021

DO - 10.1016/j.molstruc.2019.02.021

M3 - Article

SN - 0022-2860

VL - 1184

SP - 92

EP - 101

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

ER -

Mhlongo MR, Koao LF, Kroon RE, Motaung TE, Motloung SV. Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique Journal of Molecular Structure. 2019 May 15;1184:92-101. doi: 10.1016/j.molstruc.2019.02.021, 10.1016/j.molstruc.2019.02.021

Effects of annealing period on the structure and photoluminescence of the mixed phases ZnAl ₂ O ₄ /ZnO/SrAl ₂ O ₄ /Sr ₃ Al ₂ O ₆ :0.025% Tb ³⁺ nanophosphor synthesized by sol-gel technique

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