Preperation And Properties Of (OXO) Nitridosilicate Phosphor For White LED

Nowadays,white light-emitting diodes?White LED?are expected to be next generation white light source due to their promising advantages such as lower energy consumption,long lifetime,environmental protection and so on.The photolumminescence properties and stability of phosphor have a decisive influence of the luminescence,color rendering index and color temperature of white LED.The white LED composed of blue LED chip and yellow phosphor shows a poor color rendering index and high color temperature due to the lack of red light component.The white LED using tri-colored phosphor?red,green and blue?excited by a near ultraviolet?UV?chip shows uncontrollability because of too many kinds of phosphors.Besides,the optical efficiency of the UV chip still needs to be improved.So,the packaging method of green phosphor and red phosphor excited by a blue LED chip have been mainstream currently.Between many phosphor systems which applied to white LED devices of high luminescence and color rendering,the?oxo-?nitride phoshpor doped with rare earth elements can be excited by UV to blue light effectively and emit light of blue to red region.The?oxo-?nitride phoshpor has a broad emitting light spectra range and excellent luminescence properties.In this paper,Ba₃Si₆O₉N₄:Eu²⁺,BaSi₂O₂N₂:Eu²⁺and(Sr_1-xBa_x)₂Si₅N₈:Eu²⁺phosphor are selected as the research object.The influence of preperation method,calcination temperature,doping concentration,high temperature and high humidity environment on the luminescent properties of phoshpor is studied.Use the package of blue chip,red phosphor and green phosphor to acheive white LED.The impact of high temperature and high humidity environment on the optical properties of white LED is also researched.The main research contents are:1.(Sr_1-xBa_x)₂Si₅N₈:Eu²⁺phosphors were prepared by high temperature solid state method.The influence of different Ba²⁺doping concentration,high temperature and high humidity environment on the luminescence properties and thermal stability of phosphor was studied.It is found that with the increase of the Ba²⁺doping concentration,the blue shift phenomenon occured and the thermal stability are improved greatly.The causes were explained with the band structure and bond length of(Sr_1-xBa_x)₂Si₅N₈:Eu²⁺phosphor.Besides,this phosphor was packaged with blue LED chip and green phosphor to achieve white LED.The effect of high temperature and high humidity environment on the optical properties of white LED was studied.2.Ba₃Si₆O₉N₄:Eu²⁺phosphor was synthesised by precursor method of BaSiO₃as precursor.The influence of calcination temperature,Eu²⁺doping concentration,preperation method,high temperature and high humidity environment on the luminescence properties and thermal stability of phosphor was studied.Besides,this phosphor was packaged with blue LED chip and red phosphor to achieve white LED.The effect of high temperature and high humidity environment on the optical properties of white LED was studied.3.BaSi₂O₂N₂:Eu²⁺phosphor was synthesised by precursor method of Ba₂SiO₄as precursor.The influence of calcination temperature,Eu²⁺doping concentration,preperation method,high temperature and high humidity environment on the luminescence properties and thermal stability of phosphor was studied.Besides,this phosphor was packaged with blue LED chip and red phosphor to achieve white LED.The effect of high temperature and high humidity environment on the optical properties of white LED was studied.4.Ca₃Mg₃Si₄O₁₄:Eu²⁺phosphor was prepared by high temperature solid state method.The influence of calcination temperature,Eu²⁺doping concentration,flux concentration,high temperature and high humidity environment on the luminescence properties and thermal stability of phosphor was studied.At the same time,the luminescent properties and thermal stability of Ca₃Mg₃Si₄O₁₄:Eu²⁺phosphor were compared with that of commercial green powder.