The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminesc...The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminescent intensity, post-preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn-doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100℃ and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn-doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100℃ and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn-doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photolu- minescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2＋ ions in the as-prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn-doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron-hole pairs, attributing to the transition from the triplet state （4T1） to the ground state （6A1） of the Mn2＋ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn-doped CdTe/ZnS core-shell quantum dots.展开更多
A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and...A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and the effects of radical scavenger analysis were employed for identification of intermediate species.The CL spectra for this system showed only one maximum emission peak centered around 620 nm,which was similar with photoluminescence（PL） spectra of CdTe/CdS/ZnS QDs.The CL of CdTe/CdS/ZnS QDs was induced by direct chemical oxidation and the possible mechanism could be explained by radiative recombination of injected holes and electrons.This investigation not only provided new sight into the optical characteristics of CdTe/CdS/ZnS QDs,but also broadened their potential optical utilizations.展开更多
文摘纳米技术研究体系中量子点是重要的研究模块之一,量子点尺寸非常小,具有独特的光物理特性。该文旨通过实验进行分析,实验过程选择99%纯度硼氢化钠、99%纯度硫酸锌、S212恒速搅拌器、TG16-WS高速离心机、0.310 mL巯基乙酸等,制备0.4565 g CdCl_(2)·2.5H_(2)O混合液,当样本溶液呈现橙色时,表明CdTe核已制备完成。实验结果显示:单脉冲能量增加时,τ_(-rise)与τ_(2)有所降低,τ_(1)数值增加,τ_(-rise)与壳层厚度呈正比关系。通过对量子点荧光特性的分析,有利于促进核壳结构量子点的制备。
基金Project supported by the Hubei Science Foundation （No. 2010CDA061）, the Science Foundation of the Education Department of Hubei Province （No. D200922005） and Team Foundation of the Education Department of Hubei Province, and the Scientific Foundation of Huangshi City.
文摘The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminescent intensity, post-preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn-doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100℃ and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn-doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100℃ and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn-doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photolu- minescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2＋ ions in the as-prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn-doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron-hole pairs, attributing to the transition from the triplet state （4T1） to the ground state （6A1） of the Mn2＋ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn-doped CdTe/ZnS core-shell quantum dots.
基金supported by the National Natural Science Foundation of China(Nos.81373373,21435002,21227006)
文摘A novel chemiluminescence（CL） performance of CdTe/CdS/ZnS quantum dots（QDs） with periodate（KIO_4） was studied.Effects of concentration and pH on the CL system were investigated.Electron spin resonance（ESR） and the effects of radical scavenger analysis were employed for identification of intermediate species.The CL spectra for this system showed only one maximum emission peak centered around 620 nm,which was similar with photoluminescence（PL） spectra of CdTe/CdS/ZnS QDs.The CL of CdTe/CdS/ZnS QDs was induced by direct chemical oxidation and the possible mechanism could be explained by radiative recombination of injected holes and electrons.This investigation not only provided new sight into the optical characteristics of CdTe/CdS/ZnS QDs,but also broadened their potential optical utilizations.
