Investigation of Preparation and photoluminescence properties of phosphors used for near ultraviolet and blue LEDs.

Abstract : Because white light emission diodes can offer benefits in terms of high luminous efficiency, energy savings, long persistence, environmental friendliness, small volume and lack of toxic mercury, they have been considered as the next generation solid state lighting system. Several approaches have been explored to achieve these qualities in LED-based white lighting. Presently, the most common white LED design employs a blue or NUV LEDs and to pump phosphors that emit at longer wavelengths where LED performance is deficient. Here, Ba2Mg(BO3)2:Eu,Mn, Eu2+ doped oxyapatite-type Mx-yLn10-x(SiO4)6O27-2+x/2 :Euy (M=Mg, Ca, Sr, Ba, Ln=Y, La, Gd) and their oxynitrides, Sr2Si5N8:Eu2+ phosphors and MCN2:Eu (M= Ca,Sr) by means of high temperature solid-state reaction have been prepared successfully. Their phase structure and photoluminescence properties have been investigated in detail by the measurements of XRD, FT-IR spectra, O/N analyzer, photoluminescence spectra at different temperature, photoluminescence decay time and SEM. The results show that Ba 2 Mg(BO 3 ) 2 :Eu,Mn exhibit excellent orangish-red emission under the excitation ranging from 250-450 nm. Oxyapatite-type MxLn10-2+x(SiO4)6O27-x/2:Eu phosphors show emission color from bluish-green to orangish-yellow according to M2+ and its content, Ln3+ and Eu2+ concentration, orangish-red emission can be obtained by the introduction of N in the host lattice under the excitation ranging from 280-510 nm. Pure Sr2Si5N8:Eu0.04 red phosphor were gained by using SrCN2:Eu and Si3N4 as starting materials at 1300 °C under NH3 atmosphere. Eu2+:SrCN2 shows a broad band red emission with a peak at 610nm when it is excited by 350-520nm at 77K.
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Shuanglong Yuan. Investigation of Preparation and photoluminescence properties of phosphors used for near ultraviolet and blue LEDs.. Material chemistry. Université de Rennes 1; East China University Of Science and Technology (ECUST), 2010. English. ⟨tel-02291021⟩

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