Chem. J. Chinese Universities ›› 2009, Vol. 30 ›› Issue (9): 1696.

• Articles • Previous Articles     Next Articles

Preparation and Size-dependent Upconversion Luminescence Mechanism of Y2O2S∶Yb, Ho Nanoparticles

XING Ming-Ming, CAO Wang-He*, FENG Wei, PANG Tao, LING Xiao-Qiao   

  1. Optoelectronic Technology Institute, Dalian Maritime University, Dalian 116026, China
  • Received:2009-01-19 Online:2009-09-10 Published:2009-09-10
  • Contact: CAO Wang-He. E-mail: whcao_dl@126.com
  • Supported by:

    国家自然科学基金(批准号: 10374011)资助.

Abstract:

A series of Y2O2S∶Yb,Ho upconversion particles were prepared using an improved homogeneous precipitation method combined with a solid-gas sulfuration technology. The structure and morphology of particles were characterized by X-ray diffraction(XRD) and transmission electron microscope(TEM), and the upconversion luminescence(UCL) properties and mechanisms were studied by UCL spectra and FT-infrared spectra(FTIR). The results of XRD indicated that the prepared samples were pure hexagonal structure. TEM images showed the prepared particles were mono-dispersed with regular sphere shape and exhibited the narrow size distribution with average size of 40, 80 and 200 nm, respectively. According to the ln-ln plots of emission intensity as a function of excitation power, it was found that the blue emissions varied from three-photon absorption process to two-photon absorption process with decreasing particle size. For the green and red emissions, only the two-photon absorption process was observed, but the slope values of the lnIP-lnIUCL plot increased with decreasing particle size. The mechanism of the effects of particle size on the UCL properties was discussed.

Key words: Upconversion; Luminescence mechanism; Y2O2S∶Yb, Ho

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