Er^3＋掺杂浓度对掺Er^3＋：TiO2粉末结构及其光致发光特性的影响

Influence of Er^3＋ concentration on structure and PL properties in Er^3＋-doped TiO2 powders

以钛酸正丁酯为前驱体，乙酰丙酮为络合剂，70℃下进行对前驱体改性的络合反应，获得改性前驱体Ti（O-Bu）4-x（AcAc）x．以异丙醇为溶剂，采用溶胶-凝胶（sol-gel）法制备0-3％（摩尔分数）Er^3＋掺杂TiO2粉末。差热-热重（DTA-TG）分析结果表明，掺1％（摩尔分数）Er^3＋：TiO2干凝胶粉末在烧结过程中，130-300℃之间出现两个放热峰，其余试样只出现一个放热峰，决定这一现象的结构因素同时也决定了材料中Er^3＋相对较高的分散度,X射线衍射（XRD）分析表明，700℃烧结所得的掺0-3％（摩尔分数）Er^3＋：TiO2粉末，当Er^3＋掺杂浓度为0．1％（摩尔分数）和1％（摩尔分数）时，粉末均为锐钛矿与金红石混合相，前者的金红石相衍射峰更明显；掺3％（摩尔分数）Er^3＋：TiO2粉末为单一锐钛矿相结构,700℃烧结，当Er^3＋掺杂浓度在0-1％（摩尔分数）范围内时，粉末PL强度随Er^3＋掺杂浓度提高而增强；继续增加Er^3＋掺杂浓度至3％（摩尔分数）过程中，粉末PL强度明显减弱。

The 0 to 3mol% Er^3＋-doped TiO2 powders have been prepared by the sol-gel method using the modified titanium （IV） n-butoxide [Ti（O-Bu）4-x（AcAc）x] as precursor which is prepared by chelating reaction between Ti（O-Bu）4 and acetylacetone （AcAc） at 70℃. The preparation was performed by using iso-propyl （i-PrOH） as solvent with the addition of hydrated erbium nitrated [Er（NO3）3.5H2P]. The DTA-TG results showed that there were two peaks in the region of 130 to 300℃ during sintering for the 1 mol% Er^3＋-doped TiO2 xerogel, whereas there was only one peak for the other three powders. The reason which caused this phenomenon, also improved the dispersion of Er^3＋ ions. The XRD analysis showed that, the phase structure for the TiO2powders sintered at 700℃ with the Er^3＋ doping concentration of 0.1% and 1 mol% are the mixture of anatase and rutile in small amount, while that for the 3 mol% Er^3＋-doped TiO2 powders is anatase. The photoluminescence （PL） spectra centered at about 1.53μm with the form of multi-peak were obtained for the powders sintered at the temperature of 700℃. The 1 mol% Er^3＋-doped TiO2 powders sintered at 700℃ obtained the most strongest PL intensity at 1.53μm in the spectra. Further increasing of Er^3＋ doping concentration caused sharp decrease in the PL intensity of the powders.