Synthesis, crystal structure and optical properties of AgY 0.95Eu 0.05(WO 4) 2-x(MoO 4) x and AgY 1-xEu x(MoO 4) 2 phases with scheelite related structures are described. The 5D 0- 7F 2 electric dipole transition at 615 nm is predominant in the photoluminescence (PL) emission spectra, under 465 nm excitation. The critical concentration of Eu 3+ is x 0.5 in AgY 1-x(MoO 4) 2, beyond which concentration quenching is observed. In AgY 0.95Eu 0.05(WO 4) 2-x(MoO 4) x phases, the 5D 0- 7F 2 emission intensity of Eu 3+ is increased with the increase of Mo content. © 2011 The Electrochemical Society.

Upadhyayula V Varadaraju

Department Of Chemistry

Concentration quenching

Critical concentration

ELECTRIC DIPOLE TRANSITION

Emission intensity

MO CONTENT

Photoluminescence emission

RED PHOSPHORS

WHITE LED

Electric excitation

Emission spectroscopy

Optical properties

TUNGSTATE MINERALS

Europium

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of the Electrochemical Society

A comparative study of Eu 3+ photoluminescence in the Scheelite-type oxides LiGd(WO 4 ) 2 and LiGd(MoO 4 ) 2 is made. From the emission results, it is observed that the 5 D 0 → 7 F 2 electric dipole transition at 615 nm is predominant in both cases. The critical concentration of Eu 3+ is found to be x=0.3 in both LiGd 1-x Eu x (WO 4 ) 2 as well as LiGd 1-x Eu x (MoO 4 ) 2 . The emission intensity of Eu 3+ is higher in the tungstate host lattice vis a vis the molybdate. In addition, the emission intensity of Eu 3+ in LiGd 0.7 Eu 0.3 (WO 4 ) 2 is 3.3 times higher compared to that of Y 2 O 3 :0.05Eu 3+ commercial red phosphor. © 2019 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

ChemistrySelect

Eu 3+ Photoluminescence in LiGd(WO 4 ) 2 with Scheelite-Related Structure

Intense red phosphors, AgGd0.95Eu0.05(WO 4)2-x(MoO4)x (x = 0-2) have been synthesized and characterized by powder X-ray diffraction (XRD) and photoluminescence. Powder XRD results reveal a phase transition from monoclinic to tetragonal structure at x ≥ 0.5. All compositions with Eu3+ show red emission on excitation either in the charge-transfer band or Eu3+ levels. Intense red emission is obtained in the molybdates, AgGd0.95Eu 0.05(MoO4)2 under 465-nm excitation. Studies on AgGd1-yEuy(WO4)2 and AgGd 1-yEuy(WO4)2 (y = 0.1 - 1 in steps of 0. 1) show that the emission intensity is maximum for compositions with y = 0.2 and 0.3, respectively, and a decrease in emission intensity is observed for higher y values. The intense red emission of the tungstate and molybdate phosphors under 394 and 465 nm excitation, respectively, suggests that these materials are promising candidates as red-emitting phosphors for near-UV/blue GaN-based light-emitting diodes for white light generation. © 2005 The Electrochemical Society. All rights reserved.

Intense red-emitting phosphors for white light emitting diodes

Applied Physics A

Preparation of phosphors AEu(MoO4)2 (A = Li, Na, K and Ag) by sol-gel method

Journal of Physics and Chemistry of Solids

Luminescent properties of R2(MoO4)3:Eu3+ (R=La, Y, Gd) phosphors prepared by sol–gel process

Journal of Solid State Chemistry

Structural, spectroscopic and photoluminescence studies of LiEu(WO4)2−x(MoO4)x as a near-UV convertible phosphor

Chemical Physics Letters

Novel red phosphors for solid-state lighting: the system NaM(WO4)2−x(MoO4)x:Eu3+ (MGd, Y, Bi)

Scheelite based red phosphors for white LEDs

Journal	Journal of the Electrochemical Society
ISSN	00134651
Open Access	No