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Abstract: Spherical silver sulfide (Ag2S) nanoparticles have been synthesized using a simple and one-pot route, which is a direct heating process using silver acetate and n-dodecanethiol as raw materials.Transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and selected area electron diffraction (SAED) were used to confirm the size, morphology and crystal structure of as-obtained Ag2S nanoparticles. The size of the products can be tuned by controlling the reaction time, and the growth process of the samples has been studied by employing UV–vis absorption spectra. Furthermore, these Ag2S nanoparticles have a high tendency to self-assemble into two- or three-dimensional superlattice structures. This one-pot approach may be extended to synthesis of other metal sulfides nanoparticles. [Copyright &y& Elsevier]

Abstract: Porous Y2O3:Er plates with enhanced upconversion luminescence properties have been synthesized through a hydrothermal method, followed by a post thermal treatment. The as-obtained products exhibit red (650–670nm, 4F9/2→4I15/2) and green emission bands (520–570nm, 2H11/2, 4S3/2→4I15/2) under 980nm pumping. The shape and size of the pores in the plates can be tuned by controlling the reaction time in the autoclave. Moreover, the porous structure induces surface defects, which greatly affect the upconversion luminescence intensity and decay time. The potential mechanism for the effects of surface defects on the upconversion intensity and decay time was investigated, which could be a new complement for upconversion luminescence. [Copyright &y& Elsevier]