Structure-Luminescence Correlations in Europium-Doped Sol-Gel ZnO Nanopowders
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- 作者：Lidia Armelao ; Gregorio Bottaro ; Michele Pascolini ; Michele Sessolo ; Eugenio Tondello ; Marco Bettinelli ; Adolfo Speghini
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：March 20, 2008
- 年：2008
- 卷：112
- 期：11
- 页码：4049 - 4054
- 全文大小：101K
- 年卷期：v.112,no.11(March 20, 2008)
- ISSN：1932-7455
文摘
The present study, focused on the sol-gel synthesis of rare-earth-doped zinc oxide, highlights the crucialpoints involved in the design and development of ZnO/Eu nanosystems with peculiar and easily tunablephotophysical properties. ZnO nanopowders containing different europium amounts were prepared startingfrom zinc and europium acetate salts as the sol precursors. The densification process and the evolution of thestructural-optical properties were studied as a function of annealing performed in air between 100 and 1000
C. The microstructure and composition of the samples and their dependence on the synthesis procedurewere investigated by X-ray diffraction and X-ray photoelectron spectroscopy, whereas the emission propertieswere studied by photoluminescence spectroscopy in the energy and time domains as a function of the structuralevolution. Crystalline ZnO powders in the wurtzite structure were formed after heat treatment at 400 C,with an average nanocrystal size of ca. 20 nm. Stronger annealing conditions allowed a more extendeddensification of the oxide-based network and the removal of most -OH groups but also promoted thecrystallization of Eu2O3 at 800 C. The most intense emission bands around 600 nm due to Eu3+ transitionswere clearly observed in the annealed samples (T 
600 C). Interestingly, the observed overlap of the typicalEu3+ red emission with the characteristic green luminescence of the nanostructured ZnO matrix can besynergistically exploited for single or multicolor emission through the proper choice of the excitationwavelength.
C. The microstructure and composition of the samples and their dependence on the synthesis procedurewere investigated by X-ray diffraction and X-ray photoelectron spectroscopy, whereas the emission propertieswere studied by photoluminescence spectroscopy in the energy and time domains as a function of the structuralevolution. Crystalline ZnO powders in the wurtzite structure were formed after heat treatment at 400 C,with an average nanocrystal size of ca. 20 nm. Stronger annealing conditions allowed a more extendeddensification of the oxide-based network and the removal of most -OH groups but also promoted thecrystallization of Eu2O3 at 800 C. The most intense emission bands around 600 nm due to Eu3+ transitionswere clearly observed in the annealed samples (T 600 C). Interestingly, the observed overlap of the typicalEu3+ red emission with the characteristic green luminescence of the nanostructured ZnO matrix can besynergistically exploited for single or multicolor emission through the proper choice of the excitationwavelength.