Eu3+ doped-CdTe(CdTe:Eu3+)nanocrystals were prepared via a facile hydrothermal method,and Eu3+ was successfully incorporated into the crystal lattice of CdTe and measured by X-ray powder diffraction(XRD),transmission ...Eu3+ doped-CdTe(CdTe:Eu3+)nanocrystals were prepared via a facile hydrothermal method,and Eu3+ was successfully incorporated into the crystal lattice of CdTe and measured by X-ray powder diffraction(XRD),transmission electron microscopy(TEM),ultraviolet-visible(UV-Vis) absorption spectroscopy and fluorescence emission.The CdTe:Eu^3+ nanocrystals still have a cubic crystal structure,and the corresponding XRD peaks of CdTe:Eu3+nanocrystals shift to larger angles compared with those of pure CdTe.The CdTe:Eu3+ nanocrystals are monodisperse and the particles size is about 2-4 nm.Compared with pure CdTe,the CdTe:Eu^3+ nanocrystals have larger band gap and thus exhibit blueshift in the emission spectra,which could be accounted for by the energy transfer between Eu^3+ and CdTe.To enhance the stability and functionality of CdTe:Eu3+nanocrystals,the CdTe:Eu3+nanocrystals were coated with SiO2 and the core-shell SiO2-coated CdTe:Eu3+nanocrystals(CdTe:Eu^3+@SiO2) were prepared via microemulsion method.TEM results show that CdTe:Eu3+nanocrystals are uniformly dispersed in the shell,and CdTe:Eu3+@SiO2 nanospheres are uniformly spherical with an average diameter of about 75 nm.The fluorescence emission of CdTe:Eu3+@SiO2(567 nm) shows a blueshift compared with that of CdTe:Eu^3+nanocrystals(632 nm),possibly because of altered surface properties after SiO2 coating.CdTe:Eu^3+and CdTe:Eu^3+@SiO2 with tunable photoluminescence are potentially useful in fabricating optical and bioimaging devices.展开更多
Thioglycolic acid（TGA）-stabilized CdTe nanocrystals（NCs） were prepared with sodium tellurite as tellurium source,which avoids the cumbersome processes associated with H2Te or NaHTe sources.Fluorescent CdTe/SiO2 co...Thioglycolic acid（TGA）-stabilized CdTe nanocrystals（NCs） were prepared with sodium tellurite as tellurium source,which avoids the cumbersome processes associated with H2Te or NaHTe sources.Fluorescent CdTe/SiO2 composites were synthesized by a sol-gel method without the exchange of surface ligands.The phase structure of CdTe NCs was investigated by X-ray diffractometry.For comparison,some characterizations were done for both the CdTe NCs and the composites.CdTe NCs and CdTe/SiO2 composites were characterized with TEM,digital camera and fluorescence spectrophotometer.The stability of CdTe NCs and the composites were investigated in phosphate-buffered saline（PBS） buffer and the fluorescent properties of the composites were discussed in detail.展开更多
We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting n...We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.展开更多
基金financially supported by the National Natural Science Foundation of China (No.21364007)the Natural Science Foundation of Inner Mongolia (No.2016MS0201)the Program for Young Talents of Science and Technology of Baotou Teachers College (No.01135003)
文摘Eu3+ doped-CdTe(CdTe:Eu3+)nanocrystals were prepared via a facile hydrothermal method,and Eu3+ was successfully incorporated into the crystal lattice of CdTe and measured by X-ray powder diffraction(XRD),transmission electron microscopy(TEM),ultraviolet-visible(UV-Vis) absorption spectroscopy and fluorescence emission.The CdTe:Eu^3+ nanocrystals still have a cubic crystal structure,and the corresponding XRD peaks of CdTe:Eu3+nanocrystals shift to larger angles compared with those of pure CdTe.The CdTe:Eu3+ nanocrystals are monodisperse and the particles size is about 2-4 nm.Compared with pure CdTe,the CdTe:Eu^3+ nanocrystals have larger band gap and thus exhibit blueshift in the emission spectra,which could be accounted for by the energy transfer between Eu^3+ and CdTe.To enhance the stability and functionality of CdTe:Eu3+nanocrystals,the CdTe:Eu3+nanocrystals were coated with SiO2 and the core-shell SiO2-coated CdTe:Eu3+nanocrystals(CdTe:Eu^3+@SiO2) were prepared via microemulsion method.TEM results show that CdTe:Eu3+nanocrystals are uniformly dispersed in the shell,and CdTe:Eu3+@SiO2 nanospheres are uniformly spherical with an average diameter of about 75 nm.The fluorescence emission of CdTe:Eu3+@SiO2(567 nm) shows a blueshift compared with that of CdTe:Eu^3+nanocrystals(632 nm),possibly because of altered surface properties after SiO2 coating.CdTe:Eu^3+and CdTe:Eu^3+@SiO2 with tunable photoluminescence are potentially useful in fabricating optical and bioimaging devices.
文摘Thioglycolic acid（TGA）-stabilized CdTe nanocrystals（NCs） were prepared with sodium tellurite as tellurium source,which avoids the cumbersome processes associated with H2Te or NaHTe sources.Fluorescent CdTe/SiO2 composites were synthesized by a sol-gel method without the exchange of surface ligands.The phase structure of CdTe NCs was investigated by X-ray diffractometry.For comparison,some characterizations were done for both the CdTe NCs and the composites.CdTe NCs and CdTe/SiO2 composites were characterized with TEM,digital camera and fluorescence spectrophotometer.The stability of CdTe NCs and the composites were investigated in phosphate-buffered saline（PBS） buffer and the fluorescent properties of the composites were discussed in detail.
文摘We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.
