Sensitization Mechanism of Alumina Aerogels: Introducing Gd3+ as a Sensitizing Ion to Enhance the Luminescence Intensity of Tb3+

To enhance the luminous intensity of phosphors containing Tb3+, Gd3+ was used as a sensitizing ion to recombine with Tb3+. Gd3+ and Tb3+ ions were loaded on the Al2O3 aerogel matrix with nano porous structure via a simple and facile sol-gel method. After vacuum drying and calcination, Al2O3: Tb3+, Gd3+ composite aerogel materials were obtained. Al2O3 aerogel matrix has three-dimensional nanostructure and good chemical stability, which can provide stable crystal field and emission site for the rare earth activated ions. The results indicated that the introduction of Gd3+ can effectively enhance the luminescence intensity of Al2O3: Tb3+ at 543 nm under 260 nm UV excitation. The optimal ratio of Gd3+ and Tb3+ was determined to be 1: 1. The mechanism of Gd3+ sensitization to Tb3+ can be considered as electric multipole resonance transmission. We expected that this work could provide guidance for the development of enhancing the luminous intensity of green phosphors for lamp.