tailieunhanh - Báo cáo hóa học: " Structure and Photoluminescent Properties of ZnO Encapsulated in Mesoporous Silica SBA-15 Fabricated by Two-Solvent Strategy"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Structure and Photoluminescent Properties of ZnO Encapsulated in Mesoporous Silica SBA-15 Fabricated by Two-Solvent Strategy | Nanoscale Res Lett 2009 4 646-654 DOI S11671-009-9294-X NANO EXPRESS Structure and Photoluminescent Properties of ZnO Encapsulated in Mesoporous Silica SBA-15 Fabricated by Two-Solvent Strategy Qingshan Lu Zhongying Wang Jiangong Li Peiyu Wang Xialei Ye Received 8 January 2009 Accepted 5 March 2009 Published online 21 March 2009 to the authors 2009 Abstract The two-solvent method was employed to prepare ZnO encapsulated inmesoporous silica ZnO SBA-15 . The prepared ZnO SBA-15 samples have been studied by X-ray diffraction transmission electron microscope X-ray photoelectron spectroscopy nitrogen adsorption-desorption isotherm and photoluminescence spectroscopy. The ZnO SBA-15 nanocomposite has the ordered hexagonal mesostructure of SBA-15. ZnO clusters of a high loading are distributed in the channels of SBA-15. Photoluminescence spectra show the UV emission band around 368 nm the violet emission around 420 nm and the blue emission around 457 nm. The UV emission is attributed to band-edge emission of ZnO. The violet emission results from the oxygen vacancies on the ZnO-SiO2 interface traps. The blue emission is from the oxygen vacancies or interstitial zinc ions of ZnO. The UV emission and blue emission show a blue-shift phenomenon due to quantum-confinement-induced energy gap enhancement of ZnO clusters. The ZnO clusters encapsulated in SBA-15 can be used as light-emitting diodes and ultraviolet nanolasers. Keywords ZnO Clusters Mesoporous silica Photoluminescence Q. Lu Z. Wang J. Li El P. Wang X. Ye Institute of Materials Science and Engineering Lanzhou University Lanzhou 730000 China e-mail lijg@ Introduction Semiconductors usually exhibit quantum size effects and electric and optical properties different from bulk materials when their particle size decreases to nanometer scale 1 . The fabrication strategy for semiconductor nanostructure includes a wide variety of vapor liquid and solid state processing routes 2 . Different techniques such as .

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