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. The PL shows that upon excitation with 272 nm, the emission at 306 nm corresponds to the 6P5/2 → 8S7/2, while 312 nm is associated with 6P7/2 → 8S7/2 transitions, respectively. The prepared phosphor also exhibits the concentration quenching effect. EPR spectrum shows resonance signals at g ∼5.7, ∼4.5,∼3.3, ∼2.7 and ∼2.3 along with weak signals at g ∼2.0, ∼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.