Li^+共掺杂对掺Er^(3+):TiO_2上转换发光的增强作用  

Enhanced Upconversion Emissions of Er^(3+)-doped TiO_2 by Li^+ Codoping

作　　者：曹保胜[1] 冯志庆[1] 董斌[1] 何洋洋[2] 李慧[3] 

机构地区：[1]大连民族学院理学院,大连116600 [2]杜伊斯堡埃森大学物理系,杜伊斯堡47057 [3]大连民族学院生命科学学院,大连116600

出　　处：《材料导报》2009年第24期104-106,111,共4页Materials Reports

基　　金：国家自然科学基金(10804015);辽宁省教育厅高校科研计划项目(2008123)

摘　　要：采用非水性溶胶-凝胶法制备了0.1%Er^(3+)(摩尔分数,下同)、0%～2%Li^+共掺杂TiO_2粉末,在980nm半导体激光器(LD)激发下获得了中心波长526nm、550nm的绿色和663nm的红色上转换发光。Li^+共掺杂对掺Er^(3+):TiO_2的相结构未产生影响,但极大增强了上转换发光强度。随Li^+共掺杂摩尔分数的逐渐增大,绿色和红色上转换发光强度先增大后减小,当Li^+摩尔分数为1%时,上转换发光强度达到最大,绿色和红色上转换发光强度分别比掺Er^(3+):TiO_2提高了约330倍、30倍和60倍。Er^(3+)、Li^+共掺杂TiO_2粉末的绿色和红色上转换发光均为双光子吸收过程。Li^+共掺杂不改变Er^(3+)的上转换发光机制,但破坏了Er^(3+)的局部晶体场对称性,影响了Er^(3+)内部4f能级的跃迁几率,导致上转换发光强度增强。The 0. 1% Er^3＋-doped TiO2 powders with 0%-2% Li^＋ eodoping are performed by the non-aqueous sol-gel method. The green and red upconversion emissions centered at about 526nm, 550nm and 663rml are detected by a 980nm semiconductor laser diode excitation. The codoping of Li^＋ has no effect on the structure of Er^3＋：TiO2, however, strongly improves the upconversion emission intensity. With increasing the codoping concentration of Li^＋ , the intersity of green and red upeonversion emissions increases at first and then decreases, with highest intensity for 1% Li^＋ eodoping. The intensity of green and red emission is about 330 times, 30 times and 60 times greater than that of Er^3＋-doped TiO2 without Li^＋. The two-photon absorption upconversion process is involved in the green and red upconversion emission of Er^3＋- Li^＋ codoped TiO2. The eodoping of Li^＋ does not change the upconversion mechanism of Er^3＋ , but distort the local field symmetry of the Er^3＋ and hence increases the intra-4f transitions of Er^3＋ , which enhances the upeonversion emission intensity of Er^3＋ ： TiO2.

关 键 词：掺ER^3+ TiO_2 Li^+共掺杂 溶胶-凝胶法 上转换发光 

分 类 号：TQ171.79[化学工程—玻璃工业] TQ174[化学工程—硅酸盐工业]