Luminescence spectroscopy of CaAl12O19:Eu3+ and SrAl12O19:Eu3+ nanoparticles
Jafar Afshani, Teresa Delgado, Gheorghe Paveliuc, Hans Hagemann
Abstract
Development of red-emitting phosphors have gained enormous interest in recent year, due to their great potential for biological applications as well as display panels and solid-state lighting. Here, we present luminescence spectroscopy of deep-red-emitting CaAl12O19 (CA6) and SrAl12O19 (SA6) nanocrystals doped with Eu3+. CA6:Eu3+ and SA6:Eu3+ hexagonal nanoparticles (NPs) were prepared via a solvothermal reaction followed by a post-annealing process at 1150 °C. The luminescence spectra were obtained both at 298 and 5 K. Unaccustomed for Eu3+, the strongest emission was observed to originate from the 5D0→7F4 transition. Furthermore, emissions from the higher excited states (5D1-3) of the f-configuration of Eu3+ were also observed in these NP hosts at room temperature. In addition to the bands assigned to Eu3+ on the high symmetry D3h site, additional bands assigned to lower symmetry charge compensated sites have been identified. Crystal field (CF) parameters were obtained for the Eu3+ ion in SA6 compound, and the energy levels were estimated theoretically, which agreed well with the experimental values.