Preparation And Properties Of Phosphor In Bismuthate Glass For Warm White LED

White light emitting diodes?white-LEDs?as the fourth generation lighting source,offer great market potential as the source of decorative lighting,display backlighting,advertising lighting,car headlights,military,navigation and aviation.It possess numerous advantages including significant power reduction,environmental friendliness,long life,fast response and so on,compared with the conventional lighting sources.In the market,the great majority of white-LEDs consist of blue chip and phosphor,the preparation process is phosphor was mixed with silicone or epoxy resin and then packed on the chip surface.However,this package have some serious issues including the heat dissipation,aging of phosphors the deterioration and yellowing of the traditional silicone?epoxy resin?.In this paper,we reported bismuthate based phosphor in glass material which was prepared by the low-temperature co-sintering.The phosphor in glass for white LED is used to uniformly mix commercial phosphor into precursor glass,which has the characteristics of glass and the basic properties of phosphor.So it can obtain the same wavelength excitation as the doped phosphor and effectively avoid the influence of temperature and humidity on the phosphor.The following major tasks have been carried out:1.In this paper,bismuthate glass is chosen as precursor glass.for many reasons,such as excellent transmittance,low conversion temperature?<500°C?and melt temperature?900°C?,high mechanical strength,chemical stability,non-toxicity and so on.Experimental comparison,the bismuthate glass was prepared with following nominal composition?mol%?of 25%Bi₂O₃-70%B₂O₃-5%ZnO.2.Commercial phosphors such as YAG:Ce³⁺yellow phosphor,LuAG:Ce³⁺green phosphor and CaAlSiN₃:Eu²⁺red phosphor were successfully mixed into bismuthate glass,and different samples were studied by some testing methods.3.To explore the preparation methods of phosphor in glass for warm white LED,Three methods have been obtained through experiments:first,red phosphor film was coated on green phosphor in glass by spin coating method;second,green and red phosphor were mixed into precursor glass at the same time,and the warm WLED can be achieved by simple varying the weight ratio of bismuthate glass powders to phosphors;third,the Eu³⁺-doped bismuthate glass was prepared with 25%Bi₂O₃-70%B₂O₃-5%ZnO and xEu₂O₃ weight percent?wt%?,and the LuAG:Ce³⁺green phosphor was mixed Eu³⁺-doped bismuthate glass,the addition of europium ions complements the red light.