Er^(3+)掺杂钇稳定氧化锆的上转换发光

Upconversion Luminescence of Er^(3+)-Doped Yttrium-Stabilized Zirconia Powders

将共沉淀法制备的前驱体于1 200℃煅烧3h得到不同浓度稀土铒离子掺杂的钇稳定氧化锆基上转换粉体Zr0.92-xY0.08O1.96-0.5x∶xEr3+。用X射线衍射仪和荧光光谱仪分别测试样品的物相结构和上转换荧光光谱,探讨了样品可能的上转换机理。结果表明:样品中加入8mol%的Y3+可获得结晶性良好、单一稳定的立方型氧化锆固溶体,同时由于加入的三价钇离子和四价锆离子半径大小与价态的差异造成c-ZrO2对称性的降低并形成氧缺陷,这有利于样品的上转换发光性能的稳定和提高,扩大其实际应用。在980nm红外光激发下,样品发出539nm(2 H11/2→4 I15/2),552nm(4 S3/2→4 I15/2)左右的绿光和656nm,680nm(4 F9/2→4 I15/2)左右的红光。Er3+掺杂浓度较低(0.1mol%)时,样品的发光是以激发态吸收作用产生的绿光为主;随着Er3+掺杂浓度的增加,产生2 H11/2+4 I15/2→4 I9/2+4 I13/2,4 F7/2+4 I11/2→2 4 F9/2和4 I15/2+4 I9/2→24 I13/2的交叉弛豫作用,使得样品的绿光减弱,红光明显增强;Er3+掺杂浓度较高(9mol%)时,样品发光以红光为主,绿光微弱,交叉弛豫作用居于主导地位。

Er^3＋-doped yttrium-stabilized zirconia upconversion powders Zr0.92-x Y0.08O1.96-0.5x ：xEr^3＋（x=0.001~0.11）were synthesized via chemical coprecipitation method at 1 200 ℃for 3hours.Phase structure and upconversion luminescence spectra of the samples were characterized by X-ray diffractometer and fluorescence spectrometer,respectively.The proposed upconversion mechanism of the samples was discussed.The results indicate that good crystallinity cubic ZrO2 solid solution can be stabilized by introducing 8mol% yttrium ions.Size and valent differences between trivalent Y3＋and quadrivalent Zr4＋ions generate asymmetry and oxygen vacancies,which contribute to the stability of upconversion luminescence properties and luminescence intensity increase of the samples,and expand its practical application fields.Under 980 nm excitation,the samples emit green light centered at 539nm（^2 H11/2→^4 I15/2）,552nm（^4 S3/2→^4 I15/2）and red light at 656 and 680nm（^4F9/2→^4 I15/2）.When Er^3＋doping concentration（0.1mol%）is low,the main green emission of samples is ascribed to the excited state absorption（ESA）processes;With the Er^3＋concentration increases from 0.1%to 11mol%,there exist three cross relaxation（CR）processes：^2 H11/2＋^4 I15/2→^4 I9/2＋^4 I13/2,^4 F7/2＋^4 I11/2→2^ 4 F9/2and ^4 I15/2＋^4 I9/2→2 ^4 I13/2,causing that the red emissions increase markedly whereas the green emissions decrease.When Er^3＋doping concentration（9mol%）is high,the sample mainly presents red luminescence due to the dominated CR processes in upconversion process.