Visible light stimulating dual-wavelength emission and O vacancy involved energy transfer behavior in luminescence for coaxial nanocable arrays

Abstract

We report a strategy to investigate O vacancy (VO) involved energy transfer and dual-wavelength yellow emission in coaxial nanocable. By electric field deposition and subsequent sol-gel template approach, ZnO:Tb/Y2O3:Eu coaxial nanocable arrays are synthesized. After visible light excitation, system is promoted to O vacancy charge transfer state of VO(0/+). In the following cross relaxation, energy transfer from VO to the excitation energy level of Tb3+ in ZnO:Tb core area. While in Y2O3:Eu shell area, energy transfer to the excitation energy level of Eu3+. Subsequently, dual-wavelength emission is observed. By constructing nanocable with dual-wavelength emission, yellow luminescence is obtained. Adjust doping concentration of Eu3+ or Tb3+ in the range of 0.01–0.05, chromaticity coordinates of ZnO:Tb/Y2O3:Eu nanocable stably stays at yellow region in color space except ZnO:Tb0.01/Y2O3:Eu0.01. As Vo states act as media in energy transfer process in nanocablers, visible light can stimulate dual-wavelength emissions. Yellow luminescent nanocable arrays will have great applications in light-emitting diode luminescence.

Strong near band edge emission of (Ce, Yb) co-doped ZnO thin films after high temperature annealing

“…But it has not been easy to accommodate RE ions into the ZnO lattice due to the mismatch of charge and radius between the RE ion and Zn 2+ ; and even if preferred RE 3+ ions were somehow introduced into the ZnO lattice, there should still be no efficient light emissions from the RE ions, because the luminescence lifetime of RE ions is at least 10 3 times longer than the excitons decay time in ZnO. In recent years, with the great advances in synthesizing ZnO nano-structures (nano-ZnO), many research groups reported that by modulating the defects (whether extrinsic or intrinsic) of the nano-ZnO to form "energy trap centers", effective energy transfer from the host nano-ZnO to RE ions can be realized [9][10][11][12].…”