Synthesis, optical spectroscopy and Judd–Ofelt analysis of Eu3+doped Li2BaP2O7 phosphors

Abstract A series of Li 2 BaP 2 O 7 : x Eu 3+ ( x =0.1%, 1%, 3%, 5%) compound have been synthesized by the classic ceramic method. The obtained powders crystallize in the monoclinic system with C2/c space group. Excitation and emission spectra as well as luminescence decays were recorded. Five emission bands have been observed from the 5 D 0 excited state to the lower lying states 7 F 0 , 7 F 1 , 7 F 2 , 7 F 3 and 7 F 4 at 578, 590, 615, 653 and 687 nm respectively upon exciting the sample with 375 nm wavelength. The Eu 3+ Stark energy levels, the strength crystal field and the Calorimetric parameters of the Eu 3+ ions in Li 2 BaP 2 O 7 are calculated. A comparative study of the optical results obtained for the different Eu 3+ concentrations was carried out by calculating the asymmetry ratio (1). The symmetry of the local environment of Eu 3+ activators has been described in the frame of Judd–Ofelt (J–O) theory, using Ω 2 and Ω 4 intensity parameters derived from emission spectra. A comparison is made between these parameters in order to determine the type of connection between the Eu 3+ activator ions and the Li 2 BaP 2 O 7 host. The Judd–Ofelt parameters are used to calculate the relative transition probability, branching ratio and relative lifetime. The luminescence decay rates of 5 D 0 excited state is measured and the correspondent emission quantum efficiency is calculated. The effective bandwidth of the Eu 3+ (∆ λ eff ) and stimulated emission cross-section ( σ p ) are also investigated.