Suwen Liu

Luminescence characteristics of ZnS nanoparticles co-doped with Ni2+ and Mn2+

Abstract ZnS nanoparticles doped with Ni2+ and Mn2+ have been prepared by co-precipitation from homogeneous solutions of Zn, Ni and Mn salt compounds, with S2− as precipitating anion formed by decomposition of thioacetamide (TAA). X-ray diffraction analysis shows that the average crystalline particle size of the doped and undoped ZnS nanometer scale samples is about 2–4 nm. A novel luminescent property has been observed in the photoluminescence (PL) spectra of the ZnS nanoparticles co-doped with Ni2+ and Mn2+. The ZnS nanoparticles can be doped with Ni2+ and Mn2+ during synthesis without altering the X-ray diffraction pattern. However, the emission wavelengths (with a color range from blue to green, λem=475–540 nm) and PL intensities of the co-doped samples vary with changing the impurity mole ratios of Ni2+ and Mn2+ in the co-doped samples. When the mole ratios of Ni2+ and Mn2+ in the co-doped sample are 0.3% and 2.0%, respectively, the relative fluorescence intensity of the co-doped samples is about four times of that of un-doped ZnS nanocrystals. The PL properties of the co-doped samples are dramatically different from those of Ni2+- and Mn2+-doped ZnS nanocrystals.

Luminescence of CaS and MnS nanocrystallites co-activated sol–gel derived silica xerogel

Abstract CaS and MnS nanocrystallites co-activated sol–gel derived silica xerogel has been prepared by sol–gel processing. Their photoluminescence characteristics have been evaluated and compared with those of the undoped silica xerogel. Two emission bands have been observed from the doped sample, one at 440 nm while the other at 580 nm. CaS and MnS nanocrystallites embedded in sol–gel derived silica xerogel show sharp emission band. The novel luminescence phenomenon is attributed to the luminescent centers of CaS and MnS in the silica xerogel.

Photoluminescence characteristics of Ti2S3 nanoparticles embedded in sol–gel derived silica xerogel

Abstract Ti 2 S 3 nanocrystallites embedded in sol–gel derived silica xerogel have been prepared. Their photoluminescence (PL) characteristics have been evaluated and compared with those of pure silica xerogel. UV–vis absorption spectra, transmission electron micrograph, excitation spectra and PL spectra of the doped and undoped samples have all been investigated. Two emission peaks have been observed from the doped samples, one at 440 nm ( λ ex =380 nm) while the other at 600 nm ( λ ex =550 nm). The latter has been assigned to the Ti 2 S 3 nanocrystallites in the silica xerogel. Therefore, a novel luminescence property can be observed by introducing the semiconductor nanoparticles into the silica xerogel.