Lanthanide charge transfer energies and related luminescence, charge carrier trapping, and redox phenomena

Thermoluminescence investigation of donor (Ce3+, Pr3+, TbYou1, Bos2, Shi3 et al. 2012Phys. Rev. B682130View full textAdd to dashboardCite

“…4,5 The photon energy required to transfer an electron from the VB to a trivalent lanthanide ion is another simple but useful approach to determine the GS positions of the created divalent lanthanide relative to the top of the VB. [6][7][8] Once the position of the levels for only one lanthanide ion is known, the position of 4f and 5d levels of all other 13 lanthanides can be determined fairly well by using an empirical model developed by Dorenbos. [6][7][8][9][10] Besides quantum efficiency, the position of the ground and excited states of lanthanides relative to the CB and VB determine whether a lanthanide impurity can act as an electron trap, electron donor, hole trap, or hole donor.…”

Spectroscopy of High‐Energy States of Lanthanide Ions

“…An understanding of these states, and other highenergy states, such as charge-transfer, conduction-band, and exciton states [6,7,8,9], is crucial to the development of better materials for such applications.…”

“…Therefore, it is helpful to have some simple ways to catalog some of the experimental results. Dorenbos [33,34,6] has given simple formulae to relate the lowest-energy 4f N to 4f N −1 5d transition energies, and also charge transfer transition energies, across the lanthanide series. In another approach, Duan and co-workers [35,36] have used a "simplified model", where the Coulomb interaction is approximated by a simple exchange potential.…”

Preparação e desenvolvimento do mecanismo da luminescência persistente de materiais dopados com íons terras raras

“…O mecanismo do fenômeno de luminescência persistente para materiais contendo Eu 2+ considera que após excitação, um elétron do Eu 2+ migra para a banda de condução e depois para os defeitos [33]. A espécie resultante pode ser um íon Eu 3+ [35] …”

“…é dependente da matriz. Essa energia é consideravelmente alta para o caso dos íons livres (18 eV) mas é reduzida consideravelmente para o íon dopado em matrizes sólidas, sendo >7 eV para fluoretos, entre 6 e 7 eV para óxidos e <6 eV para sulfetos [33,34]. A partir dessas informações, utilizou-se um valor de 6,1 eV para a diferença entre os níveis fundamentais …”