摘要
用水热法合成了Tm^(3+)/Er^(3+)/Yb^(3+)三掺杂YF_3上转换发光粉末,并对其进行了结构和形貌表征。对上转换发射谱的研究表明,在相对低激发功率下,可以观察到比较明亮的近白色发光,且随着激发功率的增大,上转换发射强度迅速增大并达到饱和状态,继续增大激发功率,出现发光猝灭现象。退火温度对上转换发射强度的影响表明,随着退火温度的升高,Tm^(3+),Er^(3+)的所有特征发射峰均相对增强。上转换发射谱随Tm^(3+)浓度变化关系表明,在相对低Tm^(3+)掺杂浓度下,Tm^(3+)-Er^(3+)相互作用占优势,Tm^(3+)把能量传递给Er^(3+),Er^(3+)发射相对增强;在相对高掺杂浓度下,Tm^(3+)-Tm^(3+)之间交叉弛豫过程占优势,Er^(3+)发射相对减弱。从实验结果看出,该粉末的上转换发光非常丰富,从紫外到红外均有发射,是一种潜在的白色上转换发光及三维固体显示材料。
Tm^3＋/Er^3＋/Yb^3＋ tri-doped YF3 powders were synthesized using a facile hydrothermal method. XRD analysis found that the powders were crystallized products. Their sizes and morphologies were characterby scanning electron micrographs （SEM, Hitachi S-4800）, which indicated that most of the YF3 powders were in the sizes of hundreds of nanometers. Under 980 nm excitation, we recorded the upconversion spectra at room temperature by Hitachi F-4500. From UV to IR, plenty of upconversion emissions of Tm^3＋ and Er^3＋ were observed. For Tm^3 , - 291 nm emissions come from ^1I6→^3H6, -347 nm from ^1I6→^3F4, - 362 nm from ^1D2→^3H6, -452 nm from ^1D2→^3F4, and -475 nm from ^1G4→^3H6 can be identified in the upconversion spectra. The upconversion emissions from Er^3＋ are： -380 nm （^4G11/2→^4I15/2） , - 408 nm （^2H9/2 →^4I15/2 ）, - 521 nm （ ^2H11/2→^4I15/2 ）, - 537 nm （^4S3/2-→^4I15/2）, - 652 nm （^4F9/2→^4I15/2）. Therefore, cyan-white light were observed by naked-eye under 980 nm excitation even for a low excitation power density. With increasing of the excitation power, the emissions firstly become stronger, then weaker, at last nearly disappear. There are some discussions on the tempe-rature-dependent upconversion emission spectra, too. Crys- tallization became well after higher temperatures annealing tively stronger. Upconversion spectra depending on Tm^3 , and all emissions of Tm^3 concentration indicate that and Er^3＋ become rela- at relatively low Tm^3 concentration, Tm^3 -Er^3＋ interaction is dominant, and all Er^3＋ emissions become stronger for Tm^3 transfer energy to Er^3 ＋. When Tm^3 concentration reaches about 0.3%, Tm^3 -Tm^3 cross relaxation is dominant, and Er^3＋ emission relatively become weaker. All Tm^3 emissions become relatively stronger with Tm^3 concentration increasing. From the experimental results, we concluded that the YF3 powders should be promising materials for up-conversion white light and three-dimensional solid display.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第5期705-709,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金(10474096
50672030
10774142)
关键词
YF3粉末
上转换
发射光谱
退火温度
YF3 powders
upconversion
emission spectra
annealing temperature
