Abstract
Optical characteristics of a doped material depend on the site wherein the dopant resides. In mixed A-site perovskites, the dopant has several possibilities. This, in turn, correlates with the emission spectrum of the doped material. Here we choose Eu3+ as the dopant since it is a well-known and efficient red-luminophore. Sodium bismuth titanate (NBT-Na0.5Bi0.5TiO3) is selected as a host due to its ability to accommodate Eu over large concentration windows while maintaining optical activity. For compositions x ≥ 0.04, we show that Eux:NBT has amphoteric behavior (i.e., simultaneous dopant substitution in two competing sites). Eu3+ occupancy in Bi and Ti-sites are quantitatively estimated using Rietveld refinement. Also, the appearance of A1g breathing vibrational mode (830–860 cm−1) in Raman spectra shows the presence of Eu3+ on the Ti-site. Photoluminescence (PL) emission shows sharp and intense bands at ∼592 nm, ∼615 nm, and ∼687 nm, and one weak band at ∼652 nm, corresponding to f–f transitions of Eu3+. To evaluate the optical characteristics with varying site-substitution of Eu3+; Judd–Ofelt parameters and radiative properties are calculated for the first time in this mixed A-site titanate system. From the values of asymmetric ratios; Eu3+ ion is shown to occupy the non-centrosymmetrical sites (Bi-sites) of NBT. However, at x = 0.04, Ω2 < Ω4, which indicates long-range effects and hence Eu occupancy in centrosymmetric sites (Ti-sites). This study opens up avenues for further exploration of correlations between dopant-concentration, amphotericity, and spectrochemical response in other systems. The amphoteric behavior of dopants can tune emission intensities and produce multi-emission colors using a single-dopant. This would have implications for luminescence-based applications.
| Original language | English |
|---|---|
| Article number | 100426 |
| Journal | Materialia |
| Volume | 7 |
| DOIs | |
| Publication status | Published - 2019 Sep 1 |
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Keywords
- Amphoteric behavior
- Eu-doping
- Judd–Ofelt parameters
- Raman spectra
- Rare-earth doping
- Sodium bismuth titanate
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Amphotericity-spectroscopy correlations in Eu doped sodium bismuth titanate (Na0.5Bi0.5TiO3). / Behara, Santosh; Hari Krishna, R.; Miryala, Muralidhar; Murakami, Masato; Irfan, Mohammad; Najma, S.; Thomas, Tiju.
In: Materialia, Vol. 7, 100426, 01.09.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Amphotericity-spectroscopy correlations in Eu doped sodium bismuth titanate (Na0.5Bi0.5TiO3)
AU - Behara, Santosh
AU - Hari Krishna, R.
AU - Miryala, Muralidhar
AU - Murakami, Masato
AU - Irfan, Mohammad
AU - Najma, S.
AU - Thomas, Tiju
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Optical characteristics of a doped material depend on the site wherein the dopant resides. In mixed A-site perovskites, the dopant has several possibilities. This, in turn, correlates with the emission spectrum of the doped material. Here we choose Eu3+ as the dopant since it is a well-known and efficient red-luminophore. Sodium bismuth titanate (NBT-Na0.5Bi0.5TiO3) is selected as a host due to its ability to accommodate Eu over large concentration windows while maintaining optical activity. For compositions x ≥ 0.04, we show that Eux:NBT has amphoteric behavior (i.e., simultaneous dopant substitution in two competing sites). Eu3+ occupancy in Bi and Ti-sites are quantitatively estimated using Rietveld refinement. Also, the appearance of A1g breathing vibrational mode (830–860 cm−1) in Raman spectra shows the presence of Eu3+ on the Ti-site. Photoluminescence (PL) emission shows sharp and intense bands at ∼592 nm, ∼615 nm, and ∼687 nm, and one weak band at ∼652 nm, corresponding to f–f transitions of Eu3+. To evaluate the optical characteristics with varying site-substitution of Eu3+; Judd–Ofelt parameters and radiative properties are calculated for the first time in this mixed A-site titanate system. From the values of asymmetric ratios; Eu3+ ion is shown to occupy the non-centrosymmetrical sites (Bi-sites) of NBT. However, at x = 0.04, Ω2 < Ω4, which indicates long-range effects and hence Eu occupancy in centrosymmetric sites (Ti-sites). This study opens up avenues for further exploration of correlations between dopant-concentration, amphotericity, and spectrochemical response in other systems. The amphoteric behavior of dopants can tune emission intensities and produce multi-emission colors using a single-dopant. This would have implications for luminescence-based applications.
AB - Optical characteristics of a doped material depend on the site wherein the dopant resides. In mixed A-site perovskites, the dopant has several possibilities. This, in turn, correlates with the emission spectrum of the doped material. Here we choose Eu3+ as the dopant since it is a well-known and efficient red-luminophore. Sodium bismuth titanate (NBT-Na0.5Bi0.5TiO3) is selected as a host due to its ability to accommodate Eu over large concentration windows while maintaining optical activity. For compositions x ≥ 0.04, we show that Eux:NBT has amphoteric behavior (i.e., simultaneous dopant substitution in two competing sites). Eu3+ occupancy in Bi and Ti-sites are quantitatively estimated using Rietveld refinement. Also, the appearance of A1g breathing vibrational mode (830–860 cm−1) in Raman spectra shows the presence of Eu3+ on the Ti-site. Photoluminescence (PL) emission shows sharp and intense bands at ∼592 nm, ∼615 nm, and ∼687 nm, and one weak band at ∼652 nm, corresponding to f–f transitions of Eu3+. To evaluate the optical characteristics with varying site-substitution of Eu3+; Judd–Ofelt parameters and radiative properties are calculated for the first time in this mixed A-site titanate system. From the values of asymmetric ratios; Eu3+ ion is shown to occupy the non-centrosymmetrical sites (Bi-sites) of NBT. However, at x = 0.04, Ω2 < Ω4, which indicates long-range effects and hence Eu occupancy in centrosymmetric sites (Ti-sites). This study opens up avenues for further exploration of correlations between dopant-concentration, amphotericity, and spectrochemical response in other systems. The amphoteric behavior of dopants can tune emission intensities and produce multi-emission colors using a single-dopant. This would have implications for luminescence-based applications.
KW - Amphoteric behavior
KW - Eu-doping
KW - Judd–Ofelt parameters
KW - Raman spectra
KW - Rare-earth doping
KW - Sodium bismuth titanate
UR - http://www.scopus.com/inward/record.url?scp=85070508868&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85070508868&partnerID=8YFLogxK
U2 - 10.1016/j.mtla.2019.100426
DO - 10.1016/j.mtla.2019.100426
M3 - Article
AN - SCOPUS:85070508868
VL - 7
JO - Materialia
JF - Materialia
SN - 2589-1529
M1 - 100426
ER -