Recombination luminescence of LaPO4-Eu and LaPO4-Pr nanoparticles

The study of the spectral-luminescence parameters of LaPO4-Eu and LaPO4-Pr nanoparticles upon excitation by the synchrotron radiation with photon energies 4–40 eV was performed. The differences of the luminescence intensity dependence on the size for LaPO4-Eu and LaPO4-Pr nanoparticles excited at the range of matrix transparency, the range of band-to-band transitions, and the range of electronic excitation multiplication were revealed. The observed regularities are explained in terms of the electron-phonon and electron-electron scattering, surface losses, and exciton diffusion. The ratio between the length of thermalization and electron mean free path and the size of nanoparticle is determinative for the luminescence intensity upon excitation in the range of fundamental absorption of matrix and X-ray excitation.