New highly efficient green phosphor for LEDs

Mihail Nazarov, Boris Tsukerblat, Do Young Noh

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

To develop a highly energy-efficient white light sources, one needs to design highly efficient yellow, green and red phosphors, which are able to absorb excitation energy of blue LEDs and generate emissions. In this paper, results on production of a new green multiphase thiogallate phosphor {SrGa 2S4 + MgGa2O4}: Eu2+ with improved luminescence properties have been presented. The detailed XRD analysis, Raman spectroscopy and PL study have been carried out in order to enlarge the understanding of the radiative processes in {SrGa2S 4+ MgGa2O4}:Eu2+, based on two different crystallographic phases {SrGa2S4} and {MgGa 2O4}, prepared by solid state reaction at 900-1000°C during 4 h with a carbon reduction atmosphere. A model of 4f-5d optical transitions with due account for the electron-vibrational interaction is discussed. An approximate simple expression for the shape function of the broad vibronic bands with allowance for the terms corresponding to the emission (absorption) from both ground and first excited vibrational levels is given. Within this approximation we analyze the room temperature experimental data on the 4f-5d transitions in thiogallates doped with Eu2+ ions. The vibronic coupling parameters, Stokes shift and nephelauxetic effect for systems under study are estimated. The theoretical results are in a good agreement with the experimental data.

Original languageEnglish
Pages (from-to)147-150
Number of pages4
JournalIndian Journal of Engineering and Materials Sciences
Volume16
Issue number3
StatePublished - 1 Jun 2009

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