Synthesis And Investigation Of Oxynitride Phosphors For Light Emitting Diode

This paper investigated the luminescence properties of different rare earthirons doped phosphors such as Ba3Si6O12N2based phosphors、Ba3Si6O9N4basedphosphors and Ca3Si2O4N2based phosphors.The Eu2+-doped Ba3Si6O12N2green phosphor (EuxBa3-xSi6O12N2) wassynthesized by high temperature solid state method (twice sintered). It could beefficiently excited by UV-blue light (280-500nm) and showed a single intensebroadband emission at526nm. The effects of the doped-Eu2+concentration inBa3Si6O12N2:Eu2+on the photoluminescence (PL) were also investigated. Thephosphors has concentration quenching effect at x=15%and a systematic red-shift inemission wavelength with the increase of Eu2+concentration. A Ce3+/Eu2+co-activated Ba3Si6O12N2phosphor has been synthesized by traditional solid-statereaction. It was found that the luminescence intensity of the Ba3Si6O12N2:Eu2+phosphors can be efficiently enhanced by codoping with Ce3+. The resonance-typeenergy transfer mechanism from Ce3+to Eu2+in Ba3Si6O12N2:Ce3+, Eu2+phosphors isdominant by electric dipole-dipole interaction. This study prepared a kind of singlehost white emitting phosphors by Ce3+, Tb3+co-activated Ba3Si6O12N2.The Eu2+-doped Ba3Si6O9N4green phosphor (EuxBa3-xSi6O9N4) was synthesizedby high temperature solid state method (twice sintered). It could be efficientlyexcited by UV-blue light and showed a single intense broad emission band(470-625nm). The effects of the doped-Eu2+concentration in Ba3Si6O9N4:xEu2+onthe photoluminescence(PL) were also investigated. The phosphors has concentrationquenching effect at x=15%and a systematic red-shift in emission wavelength withthe increase of Eu2+concentration. It was found that the luminescence intensity of theBa3Si6O9N4:Eu2+phosphors can be efficiently enhanced by codoping with M(M=Ce3+, Mn2+and Dy3+). The addition of M in Ba3Si6O9N4:Eu2+remarkablyenhances the luminescent intensity by the factor of98%,88%, and66%for Ce3+,Mn2+, and Dy3+, respectively. The Eu2+-doped Ca3Si2O4N2green phosphor (EuxCa3-xSi2O4N2) was synthesizedby high temperature solid state method. It could be efficiently excited by near-UVlight and showed a single intense broad emission band (470-625nm). The effects ofthe doped-Eu2+concentration in Ca3Si2O4N2:Eu2+on the photoluminescence(PL)were also investigated. The phosphors have concentration quenching effect atx=0.8%. It founds that the emission intensity of Ca3Si2O4N2:Eu2+could be enhancedby addition of NH4Cl and H3BO3. In addition, emission intensity could also begreatly enhanced through doping Ce3+and K+in Ca3Si2O4N2:Eu2+phosphors. K+ionscould be used as charge compensation in Ca3Si2O4N2:Eu2+, Ce3+phosphors. Whenthe doping concentrations of Ce3+were1mol%, the emission intensity reached amaximum, which was about168%of that of the sample without doping Ce3+or K+.