BaFBr中O^(2-)的发光研究  

Luminescence of Oxygen-impurity in BaFBr

作　　者：周映雪[1] 汪东升[1] 张新夷[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,安徽合肥230029

出　　处：《发光学报》2001年第2期164-166,共3页Chinese Journal of Luminescence

基　　金：中国科学院九五重大项目资助课题 (KJ95T 0 3 )

摘　　要：通过比较紫外和真空紫外光辐照前后 ,BaFBr以及BaFBr∶O样品的发光 ,研究氧在光激励发光材料中所起的作用。未经辐照的样品 ,在 2 4 0nm光激发下 ,BaFBr∶O有峰值为 3 3 0、3 4 5、540nm以及 4 40、4 80、50 2nm肩峰的发光 ,而对BaFBr却探测不到发光。辐照后 ,在 2 4 0nm激发下 ,BaFBr以及BaFBr∶O样品都可观测到相近的发光 ,只是相对强度略有不同 ,指出样品的发光来源于氧。在 1 0 0～ 4 0 0nm范围内 ,BaFBr以及BaFBr∶O样品的吸收谱中存在四个宽的吸收带 ,表明紫外和真空紫外光可激发或电离占据氟离子格位的O2 -离子 ,氧在BaFBr光激励发光材料中可充当空穴陷阱。The BaF X(X= Cl,Br,I)∶Eu 2+ is a kind of photo stimulated luminescence (PSL) material.The electron and hole traps play an important role in the mechanism of PSL.Both electron and hole leave respectively their traps by photo stimulation,then recombine with light emission at the luminescence center.In BaF X ∶Eu 2+ ,the vacancy of anion will attract an electron and form the F colour center which could be electron trap.Nevertheless,what will be the hole trap?It is not clear up to now.In this paper,the emission and absorption spectra of BaFBr and BaFBr∶O 2- samples have been investigated in order to ascertain the origin of hole traps in BaF X ∶Eu 2+ . In BaFBr∶O 2- sample,in which the concentration of O 2- is about 8×10 -3 at%,the O 2- ions occupy the site of fluorine ion.At room temperature,without pre irradiation,there are some emission peaks (at 330,345 and 540nm,respectively) and shoulders (near 440,480 and 502nm,respectively) in the emission spectra of BaFBr∶O 2- ,under the excitation of 240nm,as shown in Fig.1.But,no luminescence can be observed for BaFBr.However,for both BaFBr and BaFBr∶O 2- ,similar luminescence can be seen,after the pre irradiation with ultraviolet and vacuum ultraviolet(VUV) light of 50～400nm and/or 185nm,under the exitation of 240nm.Their emission peaks locate at 332,348,390,442,467,502 and 540nm approximately, although ,the relative intensities of these peaks have minor differences for both samples(Fig.2).We believe that the origin of the luminescence of BaFBr and BaFBr∶O 2- is due to the oxygen impurity. Furthermore,taking the reflection spectrum of Au thin film as reference,the reflection spectra of BaFBr and BaFBr∶O 2- samples are measured in the range of 100～400nm at U10B station of the National Synchrotron Radiation Laboratory(NSRL).The absorption spectra are calculated from these reflection spectra by using K K relation.It is found that there are four broad absorption sub

关 键 词：光激励发光 空穴陷阱 氧 BAFBR 

分 类 号：O482.31[理学—固体物理]