980nm激发下YLiF_4∶Er^(3+),Tm^(3+),Yb^(3+)中的能量传递过程

Energy Transfer Process in YLiF_4∶Er^(3+),Tm^(3+),Yb^(3+) Excited by 980 nm

利用水热法合成了YLiF4∶Er3+,Tm3+,Yb3+,其中Er3+、Yb3+和Tm3+的摩尔分数分别为2%、1.5%和2%。在这种共掺杂体系中,在980nm光的激发下,材料的上转换发光为白光,发光峰不仅分别位于665nm(651nm)、552nm(543)、484nm和450nm处,并在648nm处还观察到了一个发光峰,其中最强的发射为红光。蓝光主要来源于Tm3+的激发态1G4到基态3H6的跃迁,绿光来源于Er3+的4S3/2和2H11/2到基态4I15/2的跃迁,红光既来源于Tm3+的1G4→3F4的跃迁,也来源于Er3+的4F9/2→4I15/2的跃迁。不同发射对应的激发光谱略有不同,当用不同波长光激发时,得到的发光不同,由此证明了Tm3+和Er3+之间存在能量传递,并且这种能量传递增强了红光的发射,降低了绿光的发射。

YLiF4：Er^3＋,Tm^3＋.Yb^3＋ is synthesized by hydrothermal method. The mole fractions of Er^3＋ , Yb^3＋ and Tm^3＋ are 2 %, 1.5 % and 2 %, respectively. The color of upconversion luminescence of YLiF4 ：Er^3＋ ,Tm^3＋ ,Yb^3＋ excited by 980 nm is white color. The upconversion spectrum exhibits distinct emission peaks at 665 nm （651 nm）, 552 nm （543）, 484 nm and 450 nm. There is another peak around in 648 nm. The strongest one is the light with the wavelength of 665 nm （651 nm）. The blue light results from the transition of ^1G4→^3H6 of Tm^3＋, green light is from the transition of ^4S3/2 （^2H11/2） →^4I15/2 of Er^3＋ ,red light originates from the transition ^1G4→^3F4 of Tm^3＋ and ^4F9/2→^-4I15/2 of Er^3＋. From the study of the excitation spectra and emission spectra, it is proved that there are different energy transfer processes between Tm^3＋ and Er^3＋ in YLiF4 ： Er^3＋ ,Tm^3＋ , Yb^3＋ excited by 980 nm. These energy transfer processes help to enhance red emission and decrease green emission.