Fabrication of luminescent and macroporous Y2O3:Eu3+-coated silica monoliths via freeze drying

In this paper, we report a new method to fabricate luminescent and macroporous Eu3+ doped Y2O3 (Y2O3:Eu3+)-coated silica monoliths. Macroporous silica monoliths were firstly prepared through freeze drying emulsions containing silica nanoparticles (silica NPs) and calcination. Then Y2O3:Eu3+ layers were loaded onto the macroporous silica monoliths by the wet impregnation method. The Y2O3:Eu3+-coated silica monoliths were characterized by field emission scanning electron microscopy, X-ray diffraction and mercury intrusion porosimetry. The silica NPs content, emulsion composition and dip times played important roles on morphologies of the Y2O3:Eu3+-coated silica monoliths. It was found that the silica monoliths still remained good macroporous structures after coating the Y2O3:Eu3+ layers. The loading amount of Y2O3:Eu3+ was also controlled by the dip times. Finally, luminescence properties of the Y2O3:Eu3+-coated silica monoliths were examined and they gave a strong emission peak of 612 nm attributed to the 5D0 → 7F2 transition of Eu3+. This method was simple, convenient and provided a novel route for fabrication of luminescent and macroporous silica monoliths.