Electron transfer processes in double lanthanide activated YPO4

This work reviews electron transfer processes in double lanthanide doped YPO4 studied using a diversity of optical techniques. The aim is to identify those transfer processes and to relate them with the location of lanthanide electron donor and lanthanide electron acceptor states within the bandgap of YPO4. Electron transfer from the valence band to a trivalent lanthanide impurity or to the conduction band was studied by traditional single photon excitation on single lanthanide doped YPO4. This work reports on YPO4 doped with the electron donor Ce3+ and co-doped with an electron acceptor Pr3+, Er3+, Nd3+, Ho3+, Dy3+, Tm3+, or Sm3+ studied by means of thermoluminescence and optical stimulated luminescence techniques. The same samples were studied by pump and probe two photon spectroscopy utilizing synchrotron photons to transfer electrons from Ce3+ to Ln3+ defects and 445 nm laser diode to probe the concentration of created Ln2+.