Efficient Energy Transfer and Enhanced Infrared Emission in Er-Doped ZnO-SiO₂ Composites

Abstract

Intense near-infrared (NIR) emission around 1534 nm has been obtained from ZnO-SiO2:Er3+ composites upon broadband ultraviolet light excitation. Remarkably, enhancement of the NIR emission as much as 20 times was achieved by optimal codoping with Li+ ions. To elucidate the relevant mechanisms, comprehensive spectroscopic measurements have been performed on ZnO-SiO2 composites with and without Er3+ ions doping. Photoluminescence spectroscopy and fluorescence decay dynamics clearly verify the efficient energy transfer from ZnO quantum dots (QDs) to Er3+ ions. Our results have not only demonstrated an efficient approach of color down-conversion but also indicated that ZnO-SiO2:Er3+ composites could be a promising material for optical amplifier using broadband UV pumping.

Energy dissipation channels affecting photoluminescence from resonantly excited Er3+ ions doped in epitaxial ZnO host films

“…Er 3þ ions bonded to the grain boundary surfaces have similarities to Er 3þ ions bonded to ZnO nanocrystals, which have been reported to be highly emission-active. 13,21,28 In contrast, there were no cracks for ZnO crystals with ZnO buffer layers and the film surfaces were entirely smooth. Under such circumstances, all Er 3þ ions would be accommodated inside ZnO crystallites.…”

“…The excitation energy is transferred from Er 3þ ions to ZnO host crystals, and vice versa. 28 In fact, Jang et al 27 demonstrated that band-edge and defect emissions of ZnO were anti-correlated with Er 3þ emissions, suggesting that the excitation energy is shared between various emission channels. The number of defects and lifetimes of individual energy levels affect the branching ratio of excitation energy toward ZnO defects and Er 3þ ions.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Despite extensive studies, how the crystal quality of ZnO hosts is correlated with emission intensities is still poorly understood. This is partly due to the difficulty in unambiguously identifying the registered sites of Er 3þ ions in ZnO lattices since the small fraction of Er 3þ ions, typically less than a few at.…”

Microstructure and Luminescence Properties of Tb3+ Doped ZnO Quantum Dots

“…Doping Al, Fe, Co, and rare earth elements will enhance the optical performance of ZnO nanomaterials. [15][16][17][18][19][20][21] Currently, rare earth (RE) ions with unique electronic structure and optical properties have been used as activators in various host matrices. [22][23][24] Taking the advantages of quantum effect and 4f -4f energy level transition of trivalent RE ions, the ZnO QDs photoluminescence and photocatalytic properties can be significantly strengthened.…”

Preparation and time-resolved fluorescence study of RGB organic crystals

“…Doping has been proven to be an efficient way to tune the emission color of fluorescent materials [31][32][33]. It is widely applied in the field of inorganic crystalline materials and organic thin film systems.…”