Surface Eu-Treated ZnO Nanowires with Efficient Red Emission

Abstract

The structural and optical properties of post surface Eu-treated ZnO nanowires (NWs) have been investigated systematically. It is found that the Eu 3+ ions are in the Eu 2 O 3 -like state located at the surface of ZnO NWs. Sharp intense red emissions in the range of 580-650 nm due to the intra-4f transition of Eu 3+ ions are observed from the sample. The temperature-dependent photoluminescence (PL) measurement shows that the intensity of the Eu 3+ ions emission is related to the near-band-edge (NBE) emission of ZnO NWs, indicating direct energy transfer from ZnO to Eu 3+ ions. Finally, the time-resolved PL measurement was carried out, and the roles played by the Eu 2 O 3 -like layers are discussed in detail. It is found that the Eu 2 O 3 layers not only suppress the deep level emission (DLE) in ZnO NWs but also provide efficient energy trap centers supporting the direct energy transfer from ZnO to Eu 3+ ions.

Synthesis and Characterization of PANI/ZnO Nanocomposites

“…Further, the intensity of the band‐edge luminescence peak systematically increased with increased loading of ZnO. The defects at the surface of nanoparticles can trap free electrons and provide alternative recombination pathways . Effective passivation of the surface defects can minimize this possibility.…”

Room Temperature Excitonic Whispering Gallery Mode Lasing from High‐Quality Hexagonal ZnO Microdisks

“…At a low pumping intensity, a spontaneous emission peak located at ≈ 380 nm (3.2632 eV) is observed, which can be attributed to the recombination of a free exciton (FX). [ 24 ] At higher excitation density, the FX becomes saturated and with a UV-enhanced back-illuminated charged coupled device (CCD) for spectral recording. A typical μ -PL spectrum of an individual ZnO disk (diameter = 12.56 μ m) is shown in Figure 3 .…”

Enhanced 2.0 μm Emission and Lowered Upconversion Emission in Fluorogermanate Glass‐Ceramic Containing LaF3:Ho3+/Yb3+ by Codoping Ce3+ Ions

“…Generally, the decay rate for an excited state derived from the measured decay lifetime τ m is composed of two terms: the intrinsic radiative decay rate (τ R ) and the nonradiative decay rate (τ NR ), primarily due to multiphonon deexcitation of the excited state. In the absence of concentration quenching effects, they are related according to the formula: . As the multiphonon relaxation rate exhibits a great dependence on the phonon energy of the host matrix, the prolonged lifetime of 1.2 μm emission could be related to the reduced multiphonon relaxation rates as a result of the incorporation of RE ions into the low phonon energy environment provided by LaF 3 nanocrystals in GC samples .…”