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Báo cáo hóa học: " Synthesis and Luminescence Properties of Core/Shell ZnS:Mn/ZnO Nanoparticles"

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: Synthesis and Luminescence Properties of Core/Shell ZnS:Mn/ZnO Nanoparticles | Nanoscale Res Lett 2009 4 78-83 DOI 10.1007 S11671-008-9205-6 NANO EXPRESS Synthesis and Luminescence Properties of Core Shell ZnS Mn ZnO Nanoparticles Daixun Jiang Lixin Cao Wei Liu Ge Su Hua Qu Yuanguang Sun Bohua Dong Received 18 September 2008 Accepted 30 October 2008 Published online 26 November 2008 to the authors 2008 Abstract In this paper the influence of ZnO shell thickness on the luminescence properties of Mn-doped ZnS nanoparticles is studied. Transmission electron microscopy TEM images showed that the average diameter of ZnS Mn nanoparticles is around 14 nm. The formation of ZnO shells on the surface of ZnS Mn nanoparticles was confirmed by X-ray diffraction XRD patterns high-resolution TEM HRTEM images and X-ray photoelectron spectroscopy XPS measurements. A strong increase followed by a gradual decline was observed in the room temperature photoluminescence PL spectra with the thickening of the ZnO shell. The photoluminescence excitation PLE spectra exhibited a blue shift in ZnO-coated ZnS Mn nanoparticles compared with the uncoated ones. It is shown that the PL enhancement and the blue shift of optimum excitation wavelength are led by the ZnO-induced surface passivation and compressive stress on the ZnS Mn cores. Keywords ZnS Mn ZnO Nanoparticles Core shell structure Luminescence II-VI Semiconductor Introduction In recent years a great deal of attention has been devoted to doped semiconductor nanomaterials mainly due to their unique luminescence properties arising from quantum confinement effects. The doping ions act as recombination D. Jiang L. Cao H W. Liu G. Su H. Qu Y. Sun B. Dong Institute of Materials Science and Engineering Ocean University of China Qingdao 266100 People s Republic of China e-mail caolixin@mail.ouc.edu.cn centers for the excited electron-hole pairs and play an influential role in determining optical properties resulting in strong luminescence. Among the semiconductor nanomaterials zinc sulfide is particularly suitable for use