Izvorni znanstveni članak
Study of up-conversion luminescence in BaTiO3: Ho3+ nanocrystals
Y. Badr
; National Institute of Laser Enhancement Sciences (NILES), Cairo University, Egypt
A. Salah
; National Institute of Laser Enhancement Sciences (NILES), Cairo University, Egypt
I. K. Battisha
; National Research Center (NRC), Department of Solid State Physics, Cairo, Egypt
Sažetak
Visible up-conversion emissions at 435, 545, 580, 675 and 690 nm and 437, 547, 575 and 675 nm have been obtained from BaTiO3 doped with 4 % Ho3+ ions in two different forms of the prepared samples, powder and thin film, under 808 nm laser diode excitation emissions. Combined with the energy level structure of Ho3+ ions and the kinetics of the visible emissions, the up-conversion mechanism has been analyzed and explained. The blue, green and red emissions of both samples have been attributed to the ground state-directed transition from 5F1, 5S2 and 5F5 states, respectively, which are populated through excited state absorption on 808 nm excitation. Nano-structure pure barium titanate and doped with different concentrations of Ho3+ ions in the form of powder and thin films have been prepared by so-gel technique, using barium acetate (Ba(CH3CHOO)2) and titanium isopropoxide (Ti((CH3)2CHO)4) as precursors. The thin films were prepared by spin-coating sol-gel method. The as-grown thin film and powders were found to be amorphous, which crystallized to the tetragonal phase after synthesization at 750 °C in air for 30 minutes. The crystallite size of thin film and powder samples both doped with 4 % Ho3+ ions, were found to be equal to 11 and 16 nm, respectively.
Ključne riječi
BaTiO3; Ho3+ doping; sol-gel; thin film; powder; up-conversion; FT-Raman; TEM; SEM
Hrčak ID:
301742
URI
Datum izdavanja:
2.5.2004.
Posjeta: 174 *