S.R. Lukić-Petrović

Structural and optical properties of europium-doped zinc oxide nanopowders prepared by mechanochemical and combustion reaction methods

Abstract Zinc oxide nanoparticles doped with europium were obtained by high energy ball milling followed by heat treatment and combustion reaction synthesis method starting from its microcrystalline powders. The influence of the preparation method approach and europium doping on the structural and optical properties of ZnO powders was investigated by X-ray diffraction, Raman and diffuse reflectance spectroscopy

Photoluminescence of Eu- and Sm-doped LiInO2 phosphor powders

Lithium-indium oxide doped with Eu3+ or Sm3+ is prepared by a solid-state chemistry method and its properties are analyzed with respect to its possible application as a phosphor material. X-ray diffraction confirmed that the present synthesis yields a product in tetragonal structural form (space group I41/amd) with no impurity phases. The optical band gaps of 3.4 eV for the Eu3+ sample and 3.5 eV for Sm3+ are found. Photoluminescence emission measurements showed that rare-earth ions substitute In in sites of D2d symmetry with single-exponential emission decays of 1.5 ms for the Eu3+-doped sample and 2.3 ms for the Sm3+ case.

Vaaisible upconversion emission of Er3+-doped and Er3+/Yb3+-codoped LiInO2

Lithium-indium oxide is a high-density (5.9 g·cm−3), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient phosphorescence when doped with Er3+ or Sm3+ ions. In this report, we demonstrate visible upconversion emission of Er3+-doped LiInO2 synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er3+ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared excitation, and it is greatly enhanced by co-doping with Yb3+ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications of this material as a low-temperature sensor.

Influence of copper on hardness of amorphous As-Se-I thin films

Abstract The paper reports on hardness of thin amorphous films of the Cux(As38·5Se54I7·5)100–x type for x = 10, 15, 20 and 25 at-% evaluated by microindentation measurements and instrumented nanoindentation testing. Values of determined microhardness are in the interval of 748–1137 MPa, while nanohardness are in the interval of 930–1591 MPa and can be regarded as moderate in the category of chalcogenide glasses. Isotropic mechanical properties on thin films surface are determined. Influence of copper on mechanical properties of As–Se–I films is discussed in terms of possible structural units in glass matrix.

Analysis of thermal processes in Cux(AsTe)100?x glasses

Chalcogenide glasses are promising materials for application in fiber optics and all-optical switching devices at telecommunication wavelengths, due to both their high transparency in the infrared region and their nonlinear refractive index. In this paper we present and discuss the results of the analysis of the processes that occur during the thermal treatment of the Cux(AsTe)100?x glass system, x?=?5 and 20?at.%. Our analysis is based on differential scanning calorimetry (DSC) curves, recorded in non-isothermal measurement conditions in temperature intervals of 300?770?K, at a heating rate of ??=?10?K?min?1. Samples with x?=?20?at.% are thermally treated at four different heating rates in order to implement kinetic analysis of the processes. The activation energy of the crystallization Ec is determined by the Kissinger and Mahadevan methods. The characteristic parameters of the crystallization process are determined using the Matusita method. We conclude that nucleation occurs in three dimensions and within the volume. The amorphous character of the as-prepared samples is verified by x-ray. A diffractogram of the glass sample with x?=?20?at.%, which was annealed at a temperature close to the crystallization temperature established by the DSC analysis, shows that structural units of copper with arsenic and copper with arsenic and telluride are formed within the amorphous matrix.