@conference{
author = "Ivetić, Tamara and Banjac, Boris and Đačanin Far, Ljubica and Ristić, Zoran",
year = "2023",
abstract = "Oxide compounds of the niobate type with the composition ANbO4 (A = Lu, Y, La, Gd) have promising properties as inorganic luminescence host materials [1-5]. The luminescence process of converting lower-energy, long-wavelength NIR light into higher-energy UV or VIS light, known as the luminescence up-conversion (UC) phenomenon, finds wide application in optical and sensor devices and bio-medical imaging and therapy [6]. The UC of rare-earth (RE)-based materials appears mainly through excited-state absorption, energy-transfer upconversion, and photon avalanche mechanisms, the latter of which is rarely found. Niobates ANbO4 (A = Lu, Y, La, Gd) show energy-transfer UC luminescence when doped with Er3+, Ho3+, and Tm3+ ions as activators and often co-doped with Yb3+ ions as sensitizers [7]. The choice of yttrium niobate (YNbO4) as the matrix and rare-earth ions of erbium/ytterbium for UC activation seems preferable because YNbO4 has low phonon energy, is both chemically and thermally stable as a host material, with a fairly simple synthesis, while Er3+ as an activator has a suitable energy level spacing and can be excited by several IR wavelengths, and Yb3+ as a sensitizer has a higher probability of absorption under 980 nm excitation which can increase the energy-transfer UC [8]. In our recent study, erbium (1 at. %) and ytterbium (2 at. %) doped yttrium niobate (YNbO4:Er,Yb) nanocrystallites of about 31 nm were synthesized using a combustion-assisted solid-state method. Scanning electron microscopy showed uniformity of shape and particle size of several microns and no RE-dopants affecting the microstructure. Energy dispersive spectroscopy mapping confirmed the satisfactory quality of doping. Emission spectra at 980 nm excitation showed a total of 4 Er3+ emission bands from the UC process. To determine the variation of emission characteristics with temperature, the phosphor thermometry decay measurement method was used. The quality and potential of YNbO4:Er,Yb as a temperature sensor was quite good as the relative sensitivity decreased from 0.2% to 0.09% K-1 by varying the temperature from 300 to 600K.",
publisher = "Belgrade : Society for science development of Serbia",
journal = "SCOM 2023 : The 2nd Serbian Conference on Materials Application and Technology : Book of abstracts",
title = "Rare earth doped niobates for UC luminescence applications",
pages = "I-2",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13235"
}