摘要
采用红光荧光粉制备的白光LED具有高显色指数和低色温的特点。为制备具有优秀性能的红光荧光粉,本文以氟化铵、硝酸铕、硝酸钆、硝酸钠以及聚乙二醇为原料,采用水热法制备了一系列具有发光负热猝灭特性的NaGdF_(4)∶Eu^(3+)的红光荧光粉,得到的最佳样品为NaGdF_(4)∶0.25Eu^(3+),并对最佳样品进行了一系列表征。XRD结果表明,Eu^(3+)成功掺入NaGdF_(4)中;变温荧光表征测试结果表明,最佳样品的发光具有负的热猝灭效应。与室温相比,132℃时的积分发射强度提高了51.07%,即使温度升高至226℃,仍能够达到常温时的水平。良好的热稳定性拓展了红光荧光粉NaGdF_(4)∶Eu^(3+)在紫外激发白光LED的应用。对负的热猝灭现象进行了机理探讨,研究发现:由于部分热量被转换为光辐射的能量,导致负的热猝灭现象的出现;将此红光荧光粉与395 nm UV芯片封装测试,可以发现其在50 mA电流下仍能保持较低的色温,与变温荧光测试结果相互印证。优异的高温性能表明,NaGdF_(4)∶0.25Eu^(3+)红光荧光粉适合作为WLED中的红光成分,具有潜在应用价值。
White LED prepared by red phosphors has high color rendering index and low color temperature.In order to prepare red phosphors with excellent properties,ammonium fluoride,europium nitrate,gadolinium nitrate,sodium nitrate,and polyethylene glycol were used as raw materials,and a series of NaGdF_(4)∶Eu^(3+) red emitting phosphors with luminescent negative thermal quenching effect were prepared by hydrothermal method.The optimal sample was NaGdF_(4)∶0.25Eu^(3+) and the samples were characterized by a series of tests.XRD results show that Eu^(3+) was successfully incorporated into NaGdF_(4).Results of variable temperature fluorescence characterization test show that the luminescence of the optimal sample had a negative thermal quenching effect.Compared with room temperature,the integral emission intensity at 132℃was increased by 51.07%,and even when the temperature increased to 226℃,it could still reach the initial strength at room temperature.The good thermal stability can expand the application of NaGdF_(4)∶Eu^(3+) red emitting phosphor in UV-excited white LEDs.The mechanism of the negative thermal quenching effect was discussed,and results show that some heat was converted into the radiation energy of light,which caused the negative thermal quenching effect.The red phosphor was packaged and tested with 395 nm UV chip,and it was found that it could still maintain a low color temperature at the current of 50 mA,which was consistent with the results of variable temperature fluorescence test.The excellent high temperature performance indicates that NaGdF_(4)∶0.25Eu^(3+) red phosphor is suitable for red light component in WLED,and has potential application value.
作者
王春伟
王亚雄
梁洁
李燕
明俊宇
黄映恒
廖森
WANG Chunwei;WANG Yaxiong;LIANG Jie;LI Yan;MING Junyu;HUANG Yingheng;LIAO Sen(School of Resources,Environment and Materials,Guangxi University,Nanning 530004,China;Guangxi Jingzheng Science and Technology Development Co.Ltd.,Nanning 530007,China;Collegeof Chemistry and Chemical Engineering,Guangxi University,Nanning 530004,China)
出处
《材料科学与工艺》
CAS
CSCD
北大核心
2021年第6期35-41,共7页
Materials Science and Technology
基金
国家自然科学基金资助项目(21661006,21965004).
关键词
红光荧光粉
负热猝灭
能量转换
水热合成
稀土发光材料
red emitting phosphor
negative thermal quenching
energy transformation
hydrothermal method
rare earth luminescent material
