6533b870fe1ef96bd12cf03e

RESEARCH PRODUCT

Recombination processes in rare-earth doped MAl2O4(M = Ca, Sr) persistent phosphors investigated by optically-detected magnetic resonance

B. HenkeWilliam M. YenUldis RogulisUldis RogulisStefan SchweizerStefan Schweizer

subject

ChemistryDopingAnalytical chemistryPhosphorSurfaces and InterfacesCondensed Matter PhysicsAcceptorSpectral lineSurfaces Coatings and FilmsElectronic Optical and Magnetic Materialslaw.inventionlawMaterials ChemistryElectrical and Electronic EngineeringLuminescenceElectron paramagnetic resonanceRecombinationExcitationNuclear chemistry

description

Single crystalline MAl 2 O 4 (M = Ca and Sr) persistent phosphors, which are nominally pure or additionally doped with Eu and Nd or Dy, respectively, were investigated for their recombination luminescence (RL) and microwave-induced changes in the RL at low temperatures. The analysis of the optically-detected electron paramagnetic resonance (EPR) spectra, recorded after ultraviolet excitation at 4.2 K, shows that intrinsic donor and acceptor centres are involved in the recombination process. Spectral dependent RL-EPR measurements on undoped CaAl 2 O 4 (CAO) and SrAl 2 O 4 (SAO) show that we deal with only one donor but at least two different acceptors. The g value of the donor is 1.99 in CAO and 1.97 in SAO; the g value of the acceptors is about 2.02. The donor-acceptor recombination energy is either emitted directly (undoped samples) or almost completely transferred to the rare-earth activators (doped samples).

yearjournalcountryeditionlanguage
2007-03-01physica status solidi (a)
https://doi.org/10.1002/pssa.200673745