Ultra-violet B emitting Gd3+ doped LaP3O9 phosphors prepared by co-precipitation procedure

Abstract

We investigate the structural and photoluminescence (PL) properties of La1-xP3O9:xGd (0.005 <= x <= 0.11) phosphor synthesized by the co-precipitation method. We observe orthorhombic phase in the phosphor by X-ray diffraction analysis. The PL shows that upon excitation with 272 nm, the emission at 306 nm corresponds to the P-6(5/2) -> S-8(7/2), while 312 nm is asso- ciated with P-6(7/2) -> S-8(7/2) transitions, respectively. The prepared phosphor also exhibits the concentration quenching effect. Electron paramagnetic resonance (EPR) spectrum shows resonance signals at g similar to 5.7, similar to 4.5, similar to 3.3, similar to 2.7 and similar to 2.3 along with weak signals at g similar to 2.0, similar to 1.7 and -1.5. At present concentrations of dopant Gd3+ ions, U-type EPR spectrum for La1-xP3O9:xGd phosphors have obtained due to the distortions in local environment of oxygen vacancies.