Preparation of white light emitting YVO4: Ln3+ and silica-coated YVO4:Ln3+ (Ln3+ = Eu3+, Dy3+, Tm3+) nanoparticles by CTAB/n-butanol/hexane/water microemulsion route: Energy transfer and site symmetry studies

摘要: Lanthanide ions (Ln3+ = Eu3+, Dy3+, Tm3+) doped YVO4 and silica coated YVO4:Ln3+ (YVO4:Ln3+@SiO2) nanoparticles have been prepared by a microemulsion route using Cetyl trimethyl ammonium bromide (CTAB)/n-butanol/hexane/water. Average crystallite sizes of annealed at 500 900 °C are found to be ∼30 ∼80 nm, respectively. Successful coating the on core could observed transmission electron microscopy. The silanol group (SiO–H) is present in samples (heated up °C) acts as luminescence quencher. intensity lifetime those were less than their counterpart samples. This has attributed multi-phonon relaxation arising from high vibrational energy (3750 cm−1). When °C, both for systems increase significantly due loss group, well extent reduction surface non-radiative process core-shell formation. In case triple doping Dy3+ Tm3+), emission more that either Eu3+ or Tm3+. related transfer Interestingly, significant difference asymmetric ratio electric dipole allowed transition magnetic was when different Ln3+ same host. observation explained basis full width half maximum peak. Based Commission Internationale d'Eclairage (CIE) coordinates calculations, only CIE close ideal white light values amongst These materials used potential nanophosphors light-emitting diodes (LEDs) applications.