2022-Sustainable Industrial Processing Summit
SIPS2022 Volume 1
Alario-Franco Intl. Symp
Solid State Chemistry
| Editors: | F. Kongoli, F. Marquis, S. Kalogirou, B. Raveau, A. Tressaud, H. Kageyama, A. Varez, R. Martins. |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2022 |
| Pages: | 154 pages |
| ISBN: | 978-1-989820-34-6 (CD) |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Synthesis, Structure and Luminescence Properties of Mn(IV) Doped Li4Ti5O12 Phosphor
Milica Sekulić1; Vesna Djordjevic2; Mina Medic2; Zoran Ristic2; Miroslav Dramicanin2;1VINCA INSTITUTE OF NUCLEAR SCIENCES, UNIVERSITY OF BELGRADE, Belgrade, Serbia and Montenegro; 2UNIVERSITY OF BELGRADE, VINCA INSTITUTE OF NUCLEAR SCIENCES, Belgrade, Serbia and Montenegro;
Type of Paper: Regular
Id Paper: 72
Topic: 52
Abstract:
In this work, one step solid state method was used to obtain Li4Ti5-xMnxO12 (x = 0 - 0.08) powders starting from oxide precursors sintered at 850°C. Tetravalent manganese ion was taken as an optical activator and incorporated in lithium titanate (LTO) material. The material can potentially be used in various applications, such as white light emitting diodes, biolabeling, thermoluminescence, etc. Manganese(IV) efficient red luminescence can be color converter of warm white LEDs, composed of a blue emitting diode combined with a green-yellow emitting phosphors, and in such way improve colour-rendering index. Also, it can be used for thermoluminescence contactless measurements. [1]
Being a transition metal with 3d3 electronic configuration Mn(IV) is subject to a significant impact of host lattice. XRD measurements confirmed that the LTO samples crystallise in cubic spinel structure with Fd-3m space group. Three out of four Li ions (in the molecular formula Li4Ti5O12) are situated at the tetrahedral 8a site, while the forth Li and Ti(IV) ions randomly occupy the octahedral 16d site with a ratio of 1:5, respectively. Point symmetry of Ti(IV)/Mn(IV) site is -3m (D3d).
Kubelka-Munk function, based on measured diffuse reflectance spectra, showed gradual decrease od band gap energy with Mn(IV) concentration increase in the set of synthesized materials. Reflection and excitation spectra showed that samples can be efficiently excited by λ=500 nm. Emission peaks of Mn(IV) centered at 681 and 696 nm originate from spin-forbidden 2Eg → 4A2g electron transitions. Lifetime of the transition was determined in 0.136-0.200 ms range.
The sample with the highest Mn(IV) emission intensity was co-doped with different concentrations of Nb(V), used as a sensitizer to improve luminescent properties. [2] It was observed that the intensity was increased up to 10%.
Keywords:
Advanced Characterization Techniques and Applications; Advances in the synthesis routes;References:
[1] Glais E., Đorđević V., Papan J., Viana B., and Dramićanin M. D. (2018) RSC Adv., 8, 18341.
[2] Huang, C.-S., Huang, C.-L., Liu, Y., Lin, S., Chan, T.-S., and Tu, H.-W. (2018) Chem. Mater., 30(5), 1769–1775.