Preparation and characterization of Tb3+ and Tb(sal)3·nH2O doped PC:PMMA blend

Tb doped polycarbonate:poly(methyl methacrylate) (Tb–PC:PMMA) blend was prepared with varying proportions of PC and PMMA. Thermal and spectroscopic properties of the doped polymer have been investigated employing Fourier Transform Infrared (FTIR) absorption and differential scanning calorimetric (DSC) techniques. PC:PMMA blend (with 10 wt% PC and 90 wt% PMMA) shows better miscibility. Optical properties of the dopant Tb3+ ions have been investigated using UV–vis absorption and fluorescence excited by 355 nm radiation. It is seen that luminescence intensity of Tb3+ ion depends on PC:PMMA ratio and on Tb3+ ion concentration. Concentration quenching is seen for TbCl3·6H2O concentration larger than 4 wt%. Addition of salicylic acid to the polymer blend increases the luminescence from Tb3+ ions. Luminescence decay curve analysis affirms the non-radiative energy transfer from salicylic acid to Tb3+ ions, which is identified as the reason behind this enhancement.