Synthesis And Luminescent Properties Of Binary Pyrophosphate Phosphor

The percentation of lighting consumption in global electric consumption is 20%.Power saving of lighting industry may be an effictive path to deal with the problem of energy scarcity which has attracted so much dedication of scientists.As the next generation of solid state lighting devise,light emiting diode?LED?bears the properties of energy saving,high eco-photon convertion efficinency,long life,small size,low contamination,etc,which will dominate the lighting market rather than the traditional lighting devise such as fluorescent lamp and indescent lamp.Phosphor plays important role in LED compenonts,development of near-UV light excited phosphors is more signifiant.The pyrophosphate phosphor has been widely investigated due to its high physical and chemical stability,low toxicty,high thermal stability,etc.As part of pyrophosphate phosphor,the binary pyrophosphate phosphor has more merits including economy and low synthesizing temperature.Based on above advantages,we employ the binary pyrophosphate as the host lattice of phosphor,doping with rare earth ions as the luminescent centers.Here is the main research topics in this dissertation:?1?A series of Eu²⁺ doped Mg_1.2Sr_0.8P₂O₇ blue phosphor has been synthesized through solid state reaction method.The crystal phase,luminescent properties has been studied.The factors such as reaction temperature,holding time and measure temperature has been analyzed.It is shown that the materials have high crystallinity and strong UV absorption ability,however,its thermal stability is poor.?2?A series of Tb³⁺ and Eu³⁺ codoped KAlP₂O₇ phosphors has been synthesized through the solid state reaction method.The energy transfer and its mechanism have been studied.The color tuning of luminescense materials based on energy transfer has been designed.The application of samples in ultra violet?UV?-LED has been researched.The results shows that Eu³⁺ sensitized by Tb³⁺ could emit characterised orange and red light.A series of green-yellow-red phosphor can be obtained through tuning the Tb³⁺ ions content based on the energy transfer.Besides,the KAlP₂O₇: Tb³⁺,Eu³⁺ phosphor shows a good luminescent perfomance in UV-LED.?3?A series of K₂CaP₂O₇: Ce³⁺,Tb³⁺ phosphors has been synthesized through the solid state reaction method.The influnece of doping on host lattice and the measurement temperature on luminescent properties,the energy transfer and its mechanism have been investigated.The results shows that the Ca²⁺ site could be occupied by doping ions through Rietveld refinement.The intensity of Tb³⁺ ions can be efficiently enhanced by doping Ce³⁺ ions.The energy transfer mechanism has been further investigated to be dipole-dipole interaction.The phosphor has low reaction temperature,high thermal stability,energy transfer efficiency and quantum yield,which shows good peformance of luminescence.