Intrinsic and impurity luminescence of CaF₂, CaF₂:Eu²⁺ and CaF₂:Eu³⁺ nanoparticles at high energy excitation

Abstract

CaF₂, CaF₂:Eu²⁺ and CaF₂:Eu³⁺ nanoparticles were synthesized by the chemical sedimentation method. The study of intrinsic and impurity recombination luminescence of the nanoparticles was carried out using synchrotron radiation. The intrinsic and impurity luminescence intensity was found to depend significantly on the nanoparticles size. The surface defects, the ratio between the thermalization length of photoelectrons and the nanoparticle size are crucial for luminescence intensity of the nanoparticles. The luminescence caused by the charge-transfer to Eu³⁺ ions is dominant for the small size nanoparticles.