Synthesis and Characterization of a Novel Sm+3 Activated NaCdVO4 Phosphors for Red Emitting Material

Abstract

Sm3+ activated NaCdVO4 phosphors were prepared by the simple solid-state reaction method. X-ray diffraction, dispersive energy (EDS), scanning electron microscope (SEM), infrared as well as photoluminescence (PL) techniques were used to characterize obtained samples. Irregular and non-uniform structures were observed by SEM. EDS spectra confirmed the presence of Na, Cd, V, O and Sm elements in each sample. Uuder 405nm excitation, the NaCd1 − xVO4: xSm (x = 0.01, 0.03 and 0.05) exhibits a bright red emission consisting mainly of four wavelength peaks at 556, 593, 650 and 700 nm. The highest emission intensity was found with a composition of x = 0.05. The analysis of PL spectra suggest that studied samples can be used as a red emitting phosphors candidates for fabrication of white LEDs. The CIE chromaticity coordinates of prepared samples were close to the blue-emitting phosphors for NaCdVO4 and red-emitting ones for NaCd0.99Sm0.01VO4, NaCd0.97Sm0.03VO4, and NaCd0.95Sm0.05VO4. The band gap energies of phosphors were calculated from reflectance data using K-M function.

Comparative examination of the physical parameters of the sol gel produced compounds La0.5Ag0.1Ca0.4MnO3 and La0.6Ca0.3Ag0.1MnO3

“…Manganites of structure Ln1-xAxMnO3 (with Ln: rare earths and A: divalent element) have interesting physical properties and enormous technological interest in various fields of application. These intrinsic features are often described in these highly correlated electron systems by the indirect exchange interactions between the Mn 3+ and Mn 4+ ions, the average ionic radius of site A, and the magnetic and orbital disorder [1][2][3][4]. In this structure manganese has a mixed valence Mn 3+ /Mn 4+ .…”

“…Indeed, the trivalent element is substituted Ln 3+ by a divalent or monovalent element leads to oxidation of the Mn 3+ ions ([Ar] 3d 4 ) into Mn 4+ ions ([Ar] 3d 3 ). The La1-xCaxMnO3 system is one of the most studied compounds in recent years due to its rich magnetic and electrical behavior [5,6]. Previous studies carried out in our laboratory [7,8] on manganites of the perovskite type of general formula La0.5Ca0.5MnO3 substituted by silver in the A site revealed that 10% silver is sufficient to destroy the state charge order and increase ferromagnetic interactions with an increase in TC.…”