Cr~（3＋）离子掺杂对Al_2O_3粉末结构及发光性能影响

采用球磨法制备了不同浓度Cr_2O_3掺杂的Al_2O_3粉体,并在700℃、1200℃空气中退火2 h。1200℃退火后样品,除掺杂浓度为1.6%的样品中出现少量γ-Al_2O_3相外,其余样品相均为纯α-Al_2O_3。样品晶格常数随着Cr~（3＋）离子浓度的增加而增加。采用波长为579 nm的激发光源对佯品进行荧...

Effect of Cr3+ Doping on Structure and Photoluminescence of Al2O3 Powders

Cr³⁺:Al₂O₃ nano-powders were prepared by ball milling method and annealed at 700℃or 1200℃for 2 h in the air.The samples annealed at 1200℃are of single phase with theα-Al₂O₃ structure,except that there are some low-intensity peaks ofγ-Al₂O₃ appearing in the Cr（1.6%）- doped sample.The samples’ lattice constants increase with the increase of the doping of Cr³⁺ ions.Using the excitation source with a wavelength of 579 nm,the photoluminescence（PL） spectra of all the samples shows a strong emission band between 469 nm and 492 nm,which is ascribed to the absorption of F⁺ color center.The samples annealed at 1200℃show a strong emission band at 694 nm caused by the transition of Cr³⁺ ions’ electronics from 2A to ⁴A₂ and the 0.3%Cr doped sample shows the greatest fluorescence emission intensity.When the doped concentration was greater than 0.3%,too many Cr³⁺ ions can couple and lead to concentration quenching.In contrast,for the samples annealed at 700℃,only the 0.3%Cr doped sample exhibits a low-intensity emission peak at 694 nm.