Persistent Luminescent Non-Doped Layered Nanosilicate

Layered Silicates (LS) such as hectorite clays have been used as host matrices for optically functional species due to their tunable structure. Luminescence has been reported for different phosphors using LS as a host host intercalated with rare earth containing compounds. However, the LS composition has OH- ions which may result in severe luminescence quenching. In the present work, a new LS material based on the hectorite structure was synthesized by replacing OH- with F-. This LS produced without doping strong blue/green emission. Also persistent luminescence was observed for this material with the main emission lifetime about 321 ms. It is the first time that such kind of luminescence has been reported for trioctahedral smectites. The origin of the luminescence was proved to be a Ti3+ impurity - originally as TiIV in the SiO2 precursor. Both conventional and persistent luminescence mechanisms were suggested for this “non-doped” system.