Microstructure and Luminescence Properties of Tb³⁺ Doped ZnO Quantum Dots

Abstract

In order to increase the exchange efficiency of solar cells by down-conversion, Tb3+ doped ZnO quantum dots (QDs) were successfully synthesized by sol-gel process. The X-ray diffraction (XRD) results indicate that ZnO QDs have hexagonal wurtzite structure. ZnO QDs have a spherical shape and diameter around 5 nm, which was confirmed by high-resolution transmission electron microscopy (HRTEM). The intensity of visible light emission peaks becomes strengthened and then weakened with the increase of Tb3+ doping concentration. When the concentration is more than 1%, because of the decrease of surface defects and concentration quenching effect, the emissive intensity is weakened. The enhancement of the PL emission peaks at 542 nm, 582 nm, and 619 nm was assigned to energy transfer between TbS+ ions and ZnO QDs host. Moreover, the absorption spectra also demonstrates energy transfers from Tb3+ ions to ZnO QDs.

White Light Emission from Thin-Film Samples of ZnO Nanocrystals, Eu3+ and Tb3+ Ions Embedded in an SiO2 Matrix

“…There have been substantial studies demonstrating the energy transfer specifically from ZnO-nc to Eu 3+ ions [6,7,8,9,10,11,12,13,14,15,16,17,18] and also from ZnO-nc to Tb 3+ ions [19,20,21,22,23]. Previous works by our group have also reported on the study of the energy transfer mechanism, contribution and transfer efficiency from various ZnO-nc emission centers to Eu 3+ ions [17,18,24] and Tb 3+ ions individually [23].…”

White and Tunable Emission from and Rhodamine B Detection by Modified Zinc Oxide Nanowalls

“…To date, most studies have focused on Eu­(III)-doped ZnO nanostructures. − Because the optical application of RE­(III)-doped ZnO nanostructures relies on the energy transfer from ZnO to RE­(III), Eu­(III) is less effective than Tb­(III) due to the larger energy difference between the conduction band minimum of ZnO and the emitting level for Eu­(III) ( 5 D 0 ) than that for Tb­(III) ( 5 D 4 ). Recently, Tb­(III)-doped ZnO [ZnO:Tb­(III)] nanostructured materials, such as nanorods, nanoparticles, nanocrystals, and microspheres, have been prepared by a number of methods including pulsed laser deposition and sol–gel and hydrothermal syntheses. ,,− The resulting ZnO:Tb­(III) nanostructures, however, were found to produce very weak lines as no or only trace characteristic emission originated from Tb­(III) was observed. The low emission intensities did not improve even with additional postannealing of the ZnO:Tb­(III) nanostructures.…”

Efficient energy transfer from zinc oxide nanocrystals to europium (3+) and terbium (3+) ions embedded in an oxide matrix

“…ZnO [18], Nd 3+ and Tm 3+ ions [32], respectively. Amongst the various lanthanide ions, the energy transfer from ZnO-nc to Eu 3+ ion [9, 23-28, 96, 97] and ZnO-nc to Tb 3+ ion [19,34,[98][99][100] have been most widely studied by various groups because of the usefulness of the enhanced sharp red and green emissions from Eu 3+ ions at 614 nm and Tb 3+ ions at 545 nm, respectively. Interestingly, in most of the studies on energy transfer from ZnO-nc to lanthanide ions, the focus has been to understand the structural and optical properties of such a system and the nature of the energy transfer process.…”

“…In most of the studies mentioned above, the energy transfers from ZnO-nc to a single type of lanthanide ion have been investigated. For example, the energy transfers specifically from ZnO-nc to Eu 3+ ions [24, 26-28, 45, 96, 97, 101, 103-107] or from ZnO-nc to Tb 3+ ions [35,100,[108][109][110]. Remarkably however, there has been little work on co-doping both Eu 3+ ions and Tb 3+ ions together with ZnO-nc in the same SiO 2 matrix.…”