Photoluminescence and electron-vibrational interaction in 4fn−15d states of Ce3+ or Pr3+ ions doped LnBO3 (Ln=Lu, Y, La) orthoborates materials

Abstract

Calcite, vaterite and aragonite type rare earth LnBO3 (Ln=Lu, Y, La) orthoborate powders, doped with 1% cerium or praseodymium, were prepared by the classical solid state reaction method. The structure and the morphology of these powder materials were checked by X-ray Diffraction, Fourier Transform Infra Red Spectroscopy (FTIR) and Scanning Electron Microscopy. Room temperature excitation and emission spectra of four compounds: LuBO3 with calcite and vaterite structure, YBO3 (vaterite type structure) and LaBO3 with aragonite, doped with 1% cerium or praseodymium ions, have been measured and investigated. The effect of Ce3+ and Pr3+ crystalline environment in these compounds on the position of their 5d (4f5d) levels has been discussed. This work is also devoted to the problem of the electron-vibrational interaction (EVI) in 4f–5d optical transitions in orthoborate materials. The emission and excitation 4f–5d transitions resulted in broad vibronic bands whose shape functions were described and found. The main EVI parameters, such as the Huang-Rhys factor, effective phonon energy, and zero-phonon line position, were estimated. These values are checked by modeling the Ce3+ 5d–4f and Pr3+ 4f5d–4f2 emission lines shapes, in which good agreement with experimental spectra confirms validity of the performed analysis.