摘要
采用高温固相法在1100℃下合成了Eu3+掺杂的CdxZn1-xO发光材料。采用X射线衍射对所合成样品的结构进行了表征。分析了不同浓度Cd2+的掺杂对于样品发光及激发峰位置的影响。通过对荧光光谱的测试,表明Cd2+的引入使得体系的禁带宽度变窄,并且通过Cd2+掺杂浓度的变化,可以对样品的激发光谱峰值在380～410nm进行调制,样品的发光以520nm处的宽带发射为主,并没有明显的Eu3+的特征发射,表明基质与Eu3+之间的能量传递并不有效。在加入Li+作为电荷补偿剂之后,出现了来自Eu3+的特征发射,相应的发射光谱的发射主峰位于609nm。样品380～410nm的激发峰范围覆盖了紫外LED芯片的输出波长。因此,这种荧光粉是一种可能应用在白光LED上的红色荧光粉材料。
Nowadays, along with the maturity of the nUV technology, phosphor to make white light will be more no,ticeable. For the lack of it is important significantly to explore this kind of phosphor. So, a the project that nUV LED excite tricolor phosphors matching the nUV LED chip, new-style red phosphor excited by nUV LED is discussed in this paper. Since the band-gap of CdO （2.3 eV） is smaller than that of ZnO （ 3.3 eV）, the band-gap of the material with Zn^2＋ as host can be narrowed by doping Cd^2＋. And by codoping Eu^3＋ and Li^＋, the red-light phosphor CdxZn1-xO： Eu^3＋, Li^＋ is produced. Eu^3＋ -doped CdxZn1-xO phosphor was prepared by solid-state method at 1 100℃ in atmosphere. The effect of Cd2~ doping on the luminescence and the excitation spectra of this phosphor has been analyzed. The XRD pattern of the sample shows that the phase of the sample is the simple ZnO phase, the doped ions lock-in Zn site or interstitial site. For the ion radius of Cd2~ （0. 097 nm） is larger than that of Zn2~ （0.074 nm）, when Cd2~ take place of the lattice of Zn2~ , the lattice parameter is expanded. So the XRD peaks of Cd-doped ZnO shift to small angles compared with that of pure ZnO. The excitation spectra for 609 nm emission of CdxZn1-xO： Eu is measured at room temperature. The addition of the Cd^2＋ narrow the band-gap of the system, and by changing the concentration of Cd^2＋ , the peak of the excitation spectra can be adjusted between 380 nm and 410 nm. The excitation peak at 466 nm belongs to the ^7F0-^5D2 transition of Eu^3＋ ion, and the peak at 533 nm belongs to the ^7F0-^5D1 transition of Eu^3＋ ion. The luminescence of the sample is a broad-band emission at 520 nm, but the emission of Eu^3＋ is not detected when the samples were excited by 381,387,398 and 411 nm UV light. The results show that the energy-transfer between the host and Eu^3＋ is not available. In order to enhance the energy-transfer between the host and Eu^3＋ , Li^＋ was co-doped as charge compensator. The emission of Eu^3 ＋ is detected in the emission spectra of the sample adulterating Li^＋ as charge compensator. The main peak of the emission spectra locates at 609 nm. It belongs to the s ^5D0-^7 F2 transition of Eu^3＋. For the ion radius of Li^＋ is very small, it＇s easy to enter into the crystal lattice of the host. The dopant enhances the energy-transfer between the host and Eu^3＋ and also enhances the luminescence intensity. The excitation range of the sample from 380 nm to 410 nm covers the emission wavelength of the ultraviolet LED chip. The intensity of emission was enhanced when Li^＋ is introduced into the system, and the photoluminescence of the phosphor is red. So this luminance phosphor is a possible kind of red fluorescent powder applying to white LED.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2008年第5期805-808,共4页
Chinese Journal of Luminescence
基金
国家自然科学基金(10504031,10574128)
国家“973”课题(2006CB601104)
国家“863”课题(2006AA03A138)资助项目
