Pr^(3+)或Sm^(3+)掺杂YAG∶Ce的发光特性及其荧光寿命

Luminescence Properties of YAG∶Ce Co-doped with Pr^(3+) or Sm^(3+)

研究了Pr3+,Sm3+掺杂对YAG∶Ce发射光谱及其荧光寿命的影响。观察到当掺杂Pr3+时,在609nm处出现Pr3+的发射峰,而掺杂Sm3+时,在616nm处呈现Sm3+的发射峰。掺杂Pr3+或Sm3+增加红光区的发射峰将有利于提高YAG∶Ce荧光粉的显色性。实验中测定了(Y0.95Sm0.01Ce0.04)3Al5O12、(Y0.95Pr0.01Ce0.04)3Al5O12、(Y0.96Ce0.04)3Al5O12的荧光寿命(τ),观察到在YAG∶Ce中掺入Pr3+或Sm3+使Ce3+的荧光寿命减小。实验结果表明,少量掺杂Pr3+或Sm3+并未引起基质的结构的变化。

Due to a lot of advantages, such as energy saving, high efficiency and long lifetime, white light emitting diode （W-LED） has been widely applied in many areas. The common way to fabricate W-LED is by painting a yellow-emitting phosphor on the blue LED chip. Since blue LED emits from 430 nm to 480 nm, the absorption energy for a better yellow-emitting phosphor should match that spectral region of LED emission. YAG： Ce^3＋ shows a strong broad band absorption around 465 nm and emits at about 540 nm; therefore it has been used as the main yellow-emitting phosphor in W-LED. However, the weakness of W-LED composed of blue LED and YAG： Ce^3＋ is the shortage of its red-emission component. To overcome this weakness, one of the following approaches could be chosen： 1. Adding some red-emitting components into YAG： Ce^3＋ phosphor; 2. Doping other cations in YAG： Ce^3＋ lattice. Lanthanide ions are the appropriate ones for this doping YAG： Ce^3＋ since their ionic radii are very close to that of Y^3 ＋ ion. Many papers have reported the study on lanthanide doping. In this paper, the doping effects of Pr^3 ＋ and Sm^3＋ on the luminescence properties and fluorescence lifetime of YAG： Ce were systematically studied in order to understand the rule. Phosphors were synthesized by high-temperature solid-state reaction under reducing atmosphere. ray diffraction patterns presented Pr^3＋ and Sm^3＋ can partially replace Y^3 ＋ and the lattice phases The X-ray diffraction patterns presented Pr^3＋ and Sm^3＋ can partially replace Y^3 ＋ and the lattice phases do not change . The doping effects of Pr^3 ＋ and Sm^3＋ on the luminescence properties and fluorescence lifetimes of （Y0.96%-xLnx Ce0.04）3Al5O12 （Ln = Pr^3＋, Sm^3＋） were studied. The emission and excitation spectra of the samples are recorded. In the （Y0.96-xPr, Ce0.04）3Al5O12 system the emission band of Pr^3 ＋ was at about 609 nm; and in the （Y0.96-xSmx Ce0.04） 3Al5O12 system the crease the color rendering index （CRI） of YAG： emission band of Sm^3＋ was at about 616 nm. So it can increase the color rendering index （CRI） of YAG： Ce phosphors doped by Pr^3 ＋ or Sm^3 ＋ of the Ce^3 ＋ in （ Y0.95 Pr0.01Ce0.04 ） 3Al5O12, （ Y0.95 Sm0.01Ce0.04 ） 3Al5O12, （ Y0.96 Ce0.04 The lifetime decreased due to the doping of Pr^3＋ or Sm^3 ＋ in YAG： Ce^3＋.