Title: Effect of calcination temperature on optical properties of Gd₃PO₇:Eu³⁺ nanophosphors synthesised by the combustion method

Authors: Khac Khong Minh Ngo; Vu Nguyen; Thi Kieu Giang Lam; Thi Khuyen Hoang; Manh Tien Dinh; Mariusz Stefanski; Karina Grzeszkiewicz; Dariusz Hreniak

Addresses: Institute of Materials Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam; Graduate university of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam; Nam Can Tho University, Cantho, 94000, Vietnam ' Institute of Materials Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam; Graduate university of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam ' Institute of Materials Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam; Graduate university of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam ' Institute of Materials Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam; Graduate university of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam ' Institute of Materials Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam ' Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland ' Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland ' Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland

Abstract: Red-emitting Gd₃PO₇:1mol%Eu³⁺ nanophosphors have been successfully synthesised via straightforward combustion method. Thermal behavior of the as-synthesised samples was investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Structures, morphology and optical properties of Gd₃PO₇:1mol% Eu³⁺ nanophosphors were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, and decay curve measurements. Samples were annealed at five different temperatures for 1 h. XRD analysis confirmed their monoclinic phase and the average grain sizes were calculated to be around about 20 nm. The influence of the annealing temperature on the optical properties, namely PLE, and PL spectra, as well as decay times was investigated. Under 252 nm excitation line, the strong red-emission at 615 nm due to the ⁵D₀→⁷F₂ transition was observed. It also shows that Eu³⁺ ions in Gd₃PO₇ mainly occupied noncentrosymmetric sites. The maximum intensity of ⁵D₀→⁷F₂ emission was recorded for the sample annealed at 900°C. It was found that increasing the annealing temperature leads to increase of the decay times from 1.3 ms to 1.5 ms for samples calcinated at 500°C and 900°C, respectively.

Keywords: luminescent nanomaterial; Gd₃PO₇; Eu³⁺.

DOI: 10.1504/IJNT.2020.111329

International Journal of Nanotechnology, 2020 Vol.17 No.7/8/9/10, pp.623 - 635

Published online: 20 Nov 2020 *

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