Analysis of Nd <sup>3+</sup> concentration on the structure, morphology and photoluminescence of sol-gel Sr <inf>3</inf> ZnAl <inf>2</inf> O <inf>7</inf> nanophosphor

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

© 2019 The Authors Neodymium activated strontium zinc aluminate (Sr 3 ZnAl 2 O 7 :x%Nd 3+ ) nanophosphor was synthesized using the sol-gel technique whereby the Nd 3+ concentration was varied in the range 0 ≤ x ≤ 2. The effect of Nd 3+ concentration on the structure, particle morphology and photoluminescence properties of Sr 3 ZnAl 2 O 7 were investigated. The X-ray diffraction (XRD) results revealed that all samples resembled the mixture of both ZnAl 2 O 4 and Sr 3 Al 2 O 6 cubic structures. Nd 3+ doping influenced the crystallite sizes of the prepared phosphor materials. The energy dispersive X-ray spectroscopy (EDS) results confirmed the presence of all expected elements in the composition. Scanning electron microscopy (SEM) revealed that as the Nd 3+ concentration increased the surface morphology changed to smooth mountain-like structures. The ultraviolet–visible (UV–Vis) diffuse reflection spectroscopy showed that the band gap of Sr 3 ZnAl 2 O 7 can be tuned from 2.74 to 2.95 eV by increasing the Nd 3+ concentration. When the host is excited above the bandgap (374 nm), broad emission attributed to defects occurs with the maximum near 585 nm. Doped samples excited in this manner do not exhibit additional luminescence due to the Nd 3+ ions, but in contrast there is a small dip in the defect emission band near 585 nm due to absorption attributed to Nd 3+ ions. Characteristic infrared emissions of Nd 3+ ions at 885, 1064 and 1340 nm were observed by directly exciting the Nd 3+ ions at 585 nm ( 4 I 9/2 → 5 G 5/2 + 2 G 7/2 ) and were attributed to 4 F 3/2 → 4 I 9/24 I 11/2 and 4 I 13/2 transitions, respectively. The Commission Internationale de l'Eclairage (CIE) coordinates results showed that the orange emission colour is from the host.
Original languageEnglish
Pages (from-to)1786-1796
Number of pages11
JournalResults in Physics
Volume12
DOIs
Publication statusPublished - 1 Mar 2019

Keywords

  • CIE
  • Nd activated
  • Photoluminescence
  • Sol-gel
  • Sr ZnAl O

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