CaLa2ZnO5:Gd3+ phosphor prepared by sol-gel method: photoluminescence and electron paramagnetic resonance properties

A sequence of Gd-doped CaLa2ZnO5 samples was synthesized through a sol gel method and their characterizations were done by X-ray diffraction (XRD), scanning electron microscope (SEM), electron spin resonance (ESR), and photoluminescence (PL) spectroscopic techniques. PL spectra exhibited a strong emission peak at 314 nm, showing the presence of Gd3+ ions in a CaLa2ZnO5 host lattice. This peak corresponded to 6P7/2 → 8S7/2 transition of Gd3+ ion under 227 nm excitation. ESR studies suggested Gd goes in the CaLa2ZnO5 matrix as Gd3+. By correlating the PL and ESR spectral data, the probable site symmetry of Gd3+ ion is proposed in the host matrix.