Zinc-Tin-Oxide-Based Porous Ceramics: Structure, Preparation and Properties

Zinc-tin-oxide-based ceramics have been extensively investigated especially regarding the synthesis of zinc stannate (Zn2SnO4), a spinel structure ternary compound with a wide range of possible applications. Among all of those, the best-known use of this material is in the combustion gas and moisture sensors. This chapter presents the research results review on the structure, morphology, and properties of mechanochemically synthesized Zn2SnO4 ceramics with large open porosity, as well as the results obtained during its solid-state processing optimization. Also shown is the review of the results obtained in the study of the influence of addition of the small amounts of bismuth oxide (Bi2O3) on the obtained Zn2SnO4 structure, microstructure, and electrical properties, as it provides the condition for the liquid phase sintering and creates a new dynamics in the zinc-tin-oxide reaction sintering process

Photoacousic Properties of Thin Film Zinc-Stannate

Poster presented at the The Seventh Yugoslav Materials Research Society Conference - YUCOMAT 2005, Herceg Novi, Crna Gora, September 12-16, 2005

Optical energy bandgap tuning of spinel zinc stannate by erbium/ytterbium doping

This work shows the results of an optical energy bandgap (Eg) investigation supported by scanning electron microscopy (SEM) of spinel-type zinc stannate (Zn2SnO4) upon doping with rear earth (RE3+) ions (Er3+, Yb3+). The powder samples are synthesized by a mechanochemical solid-state method with the final annealing step at 1200 C. The reference Zn2SnO4 powder sample bandgap (3.87 eV) turning lower upon doping, precisely to 3.5 eV, and 3.37 eV bandgap values found for Er-doped Zn2SnO4 and Er,Yb-codoped Zn2SnO4 powder samples, respectively is a confirmation of the successful incorporation of the RE3+ ions into the Zn2SnO4 host structure. Morphology of the obtained powders shows, in general, the non-uniformly shaped agglomerates, while their particle sizes follow up the bandgap decreasing trend with doping

Segmented thermistors printed using NTC nanometric paste on alumina and Sr-ferrite substrates

Poster presented at 12th Annual Conference of the Materials Research Society of Serbia - YUCOMAT 2010, Herceg Novi, Montenegro, 6–10. septembar 2010

Microstructure development and electrical properties of NiO doped alpha-Fe2O3

Poster presented at the 4th Serbian Congress for Microscopy, Belgrade, Serbia, 2010, October 11-12, 201

A Detailed XRD and FTIR Analysis of Bi2O3 Doped ZnO-SnO2 Ceramics

Poster presented at the 2nd International Congress on Ceramics, Verona, Italy, June 29 - July 4, 200

Rare earth doped niobates for UC luminescence applications

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.SCOM 2023 : 18th - 20st of October 2023, Belgrade