The luminescence enhancement of Eu³⁺ion and SnO₂nanocrystal co-doped sol—gel SiO₂films

Abstract

SnO2 nanocrystal and rare-earth Eu3+ ion co-doped SiO2 thin films are prepared by sol-gel and spin coating methods. The formation of tetragonal rutile structure SnO2 nanocrystals with a uniform distribution is confirmed by X-ray diffraction and transmission electron microscopy. Fourier transform infrared spectroscopy is used to investigate the densities of the hydroxyl groups, and it is found that the emission intensity from the 5D0−7F2 transitions of the Eu3+ ions is enhanced by two orders of magnitude due to energy transfer from the oxygen-vacancy-related defects of the SnO2 nanocrystals to nearby Eu3+ ions. The influences of the amounts of Sn and the post-annealing temperatures are systematically evaluated to further understand the mechanism of energy transfer. The luminescence intensity ratio of Eu3+ ions from electric dipole transition and magnetic dipole transition indicate the different probable locations of Eu3+ ions in the sol—gel thin film, which are further discussed based on temperature-dependent photoluminescence measurements.

Magnetoelectric effect in multiferroic NdMn 2 O 5

“…A polycrystalline sample of NdMn 2 O 5 was prepared by using the sol-gel method. [20,22] X-ray diffraction (XRD) measurement was performed with a Rigaku powder x-ray diffractometer using Cu Kα radiation in the 2θ range from 20 • to 80 • by step scanning at 0.02 • per step. The Rietveld refinement of the XRD pattern was performed by using the JANA2006 program.…”

Improved sensitization efficiency in Er3+ ions and SnO2 nanocrystals co-doped silica thin films

“…Our present results indicate that some Er 3+ ions remain in the amorphous silica matrix and others are trapped in the SnO 2 NCs, similar to Eu 3+ in SnO 2 NCs reported before. 31 Generally, Er 3+ ions are very hard to incorporate into Sn 4+ sites due to the large radius mismatch and the charge imbalance (0.088 nm for Er 3+ ions, 0.071 nm for Sn 4+ ions). However, it has been reported that Er 3+ ions were successfully doped into SnO 2 NCs with Er 3+ doping concentration of 0.043 at%.…”