CePO4:Ln (Ln = Tb3+ and Dy3+) Nanoleaves Incorporated in Silica Sols

Highly crystalline CePO4, CePO4:Tb3+, and CePO4:Dy3+ nanoleaves with monoclinic structure and dispersible in solvents such as water and methanol were prepared by a low temperature synthesis. Subsequently, these nanoleaves were incorporated into silica sols by the sol-gel method. Such nanoleaves incorporated into silica sols exhibit improved luminescence properties compared to silica sols directly doped with lanthanide ions. The observed difference in the luminescent properties of nanoleaves incorporated into silica sols and silica sols directly incorporated with lanthanide ions has been explained based on the different extent of energy transfer from Ce3+ to Tb3+/Dy3+ ions. The different extent of quenching of the excited-state of lanthanide ions due to OH groups from Si-OH linkages and water molecules, taking place in nanoleaves incorporated into silica sols compared to silica sols directly doped with lanthanide ions, is also responsible for the improvement in the luminescence properties. The present Study will be quite relevant for developing biosensors for studying enzyme and protein activities based on luminescent silica sols.