Sm3＋/yb3＋ co-doped tellurite glasses are prepared by melt-quenching technique. The density of the glasses varies between 4.65 and 4.84 g/cm3. The optical absorption spectra consist of eight bands in the wavelength r...Sm3＋/yb3＋ co-doped tellurite glasses are prepared by melt-quenching technique. The density of the glasses varies between 4.65 and 4.84 g/cm3. The optical absorption spectra consist of eight bands in the wavelength range of 350-2 000 nm, which correspond to the transitions from ground level 6H5/2 to the various excited states of the Sm3＋ ion. Energy band gaps vary in the range of 2.73 2.91 eV, and the Urbach energy ranges from 0.21 to 0.27. Emission spectra exhibit four peaks originating from the 4G5/2 energy level centered at 576, 613, 657, and 718 nm. Quenches in emission bands may be due to the energy transfer from the Sm3＋ to Yb3＋ ions.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
Water-soluble cadmium telluride （CdTe） nanocrystals were synthesized in aqueous solution with thioglycolic acid （TGA） molecules as a stabilizer. A series of TGA-stabilized CdTe nanocrystals were prepared using sod...Water-soluble cadmium telluride （CdTe） nanocrystals were synthesized in aqueous solution with thioglycolic acid （TGA） molecules as a stabilizer. A series of TGA-stabilized CdTe nanocrystals were prepared using sodium tellurite as a tellurium source, which avoids the cumbersome processes associated with H2Te or NaHTe sources. The synthesized TGA-stabilized CdTe were characterized with X-ray diffraction, TEM and fluorescence spectrophotometer. The particles crystallized predominantly in cubic phase with narrow photoluminescence emission. The effects of reaction time, pH value, and precursor concentration on the photoluminescence properties were investigated in detail.展开更多
基金support fromthe Research Management Centre,University Technology Malaysia (RMC,UTM) through the researchgrants (VOTE ERGS 4L032 and 07J80,MoHE)F.Nawaz extends his gratitude to the financial support by UTM through the International Doctoral Fellowship(UTM.J.10.01/13.14/1/128)
文摘Sm3＋/yb3＋ co-doped tellurite glasses are prepared by melt-quenching technique. The density of the glasses varies between 4.65 and 4.84 g/cm3. The optical absorption spectra consist of eight bands in the wavelength range of 350-2 000 nm, which correspond to the transitions from ground level 6H5/2 to the various excited states of the Sm3＋ ion. Energy band gaps vary in the range of 2.73 2.91 eV, and the Urbach energy ranges from 0.21 to 0.27. Emission spectra exhibit four peaks originating from the 4G5/2 energy level centered at 576, 613, 657, and 718 nm. Quenches in emission bands may be due to the energy transfer from the Sm3＋ to Yb3＋ ions.
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Water-soluble cadmium telluride （CdTe） nanocrystals were synthesized in aqueous solution with thioglycolic acid （TGA） molecules as a stabilizer. A series of TGA-stabilized CdTe nanocrystals were prepared using sodium tellurite as a tellurium source, which avoids the cumbersome processes associated with H2Te or NaHTe sources. The synthesized TGA-stabilized CdTe were characterized with X-ray diffraction, TEM and fluorescence spectrophotometer. The particles crystallized predominantly in cubic phase with narrow photoluminescence emission. The effects of reaction time, pH value, and precursor concentration on the photoluminescence properties were investigated in detail.
