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1.
以巯基丙酸(MPA)为稳定剂, 利用共沉淀法制备了水溶性的Ag掺杂的ZnxCd1-xS合金型纳米晶. Ag掺杂后ZnxCd1-xS纳米晶产生新的发射峰, 并且发光效率得到了有效提高. 通过改变纳米粒子中Zn/Cd比例可有效地调控ZnxCd1-xS∶Ag纳米晶的吸收带隙宽度, 同时可以在425~603 nm之间实现对ZnxCd1-xS∶Ag纳米晶发射峰位的连续调控. 相似文献
2.
HUA Rui-nian SUN Hong-jie JIANG Hui-ming SHI Chun-shan 《高等学校化学研究》2006,22(4):423-426
IntroductionPerovskite complex fluorides have attracted great ainterest due to their particular physical properties, suchas piezoelectric characteristics[1], ferromagnetic prop-erty[2], nonmagnetic insulator behavior[3], and photo-luminescence host functi… 相似文献
3.
Xiaofei Han Run Liu Zhude Xu Weixiang Chen Yifan Zheng 《Electrochemistry communications》2005,7(12):1195-1198
Nanocrystalline cadmium peroxide thin film has been electrodeposited on indium doped tin oxide glass substrate from aqueous solution at room temperature. The grain size of the nanocrystals of the film is estimated from XRD and is about 14 nm. The deposits are decomposed at 228 °C by formation of CdO, releasing plentiful heat at same time. The band-gap of the nanocrystalline CdO film made from decomposition of electrodeposited CdO2 is around 2.4 eV. 相似文献
4.
The thermal decomposition of Zn-MPA complex was investigated under microwave irradiation. ZnO and ZnS nanocrystals could be obtained by decomposing Zn-MPA(3-mercaptopropionic acid) complex under different reaction conditions. It was found that both the pH value of the solution and the molar ratio of Zn2+ and MPA can play an important role in the formation of ZnO and ZnS nanocrystals. MPA mainly acts as an S source or as a complexing agent. This study provides a new route for the controllable preparation of semiconductor nanocrystals. 相似文献
5.
We investigate the energy structure of colloidal CdS nanocrystals by measuring the UV–vis absorption spectra. Nanocrystals were synthesized by sol–gel method in a gelatin matrix in the size range from 2.5 to 3.9 (±0.2) nm. In order to interpret the UV–vis absorption spectra we calculate the energy spectrum of electron quasi-stationary states using the model of open nanocrystal as well as the hole stationary spectrum in a two-band approach. It is shown that the main contribution to the absorption spectrum is made by interband transitions 1S3/2→1Se and 1P3/2→1Pe, and its shape is determined by the size distribution of nanoparticles. For this system the estimated values of the effective masses of the heavy hole and light hole are 1.44m0 and 0.28m0, respectively. 相似文献
6.
YANG Liming GUO Lixin YU Hao WANG Guan SUN Jiangman ZHANG Pengfei GU Xinggui TANG Ben Zhong 《高等学校化学研究》2021,37(1):129-136
The development of fluorescent nanocrystals based on organic small molecules is of great importance in bioimaging due to the merits of easy modification,high brightness and excellent photostability,however suffering from the emission-detrimental aggregation-caused quenching(ACQ)effect.Herein,we successfully designed and synthesized an AIE-active di(N,N-dimethylaniline)-dibenzofulvene(named as NFTPE),which exhibits the crystallization-induced emission enhancement(CIEE)effect.Interestingly,two types of yellow-and orange-emissive crystals for NFTPE were obtained,exhibiting aggregation microenvironment-dependent emission tuning in the solid state.Single-crystal analysis and density functional theory(DFT)calculations reveal that different aggregation microenvironments result in the distinct molecular conformation for various emission.Excitingly,the crystallization of NFTPE in an aqueous solution under the assistance of amphiphilic PEG polymer matrices could be monitored in situ by the fluorescence changes,facilitating the preparation of NFTPE nanocrystals(NFTPE-NCs)by adjusting the aggregation microenvironment.The obtained NFTPE-NCs exhibit the superior performance in cell imaging in respect to high brightness,photostability,and biocompatibility,thus demonstrating the potential in bioimaging applications. 相似文献
7.
纳米NaYF4:Yb,Ho上转换荧光粉的合成及其性质研究 总被引:8,自引:0,他引:8
以EDTA为螯合剂,采用络合共沉淀法合成了纳米级镱、钬共掺杂的氟化钇钠上转换荧光材料.所合成的纳米材料颗粒均匀,分散性好.通过调节EDTA的加入量,可在41~148nm范围内调控纳米颗粒的大小.在980nm红外激光器照射下,肉眼可观察到明亮的上转换荧光,对发光机理进行了探讨. 相似文献
8.
从纳米晶到三维超晶格结构 总被引:1,自引:0,他引:1
纳米晶的有序组装对未来纳米材料的应用拓展具有重要意义. 本综述介绍了纳米晶三维超晶格的研究价值以及制备方法,着重对“胶体溶液蒸发”、“不良溶剂扩散”、“胶束引导集聚”、“氢键连接”、“静电聚集”、“DNA导向”、“外场辅助”和“水-油界面辅助”的组装机制进行了总结与评述,同时也探讨了这一新兴领域中仍然存在的挑战. 相似文献
9.
E. Verrelli I. Anastassiadis D. Tsoukalas M. Kokkoris R. Vlastou P. Dimitrakis P. Normand 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):67
We report on proton radiation tolerance of Si-nanocrystal (Si-NCs) MOS structures aiming at non-volatile memory applications. Si-NCs were formed by low-energy (1 keV) ion-beam-synthesis within a 9 nm thick SiO2 layer. A 2-D layer of Si-NCs with 3 nm mean diameter and 1012 cm−2 surface density was successfully achieved. After fabrication of Al capacitors, samples with and without Si-NCs were 1.5 and 6.5 MeV proton were irradiated at doses ranging from 1 Mrad (SiO2) to 120 Mrad (SiO2). Significant irradiation-dose-dependent shifts are detected in the C–V curves of the NC-MOS cells and programmed cells are found to undergo bit flip. Despite the above, the attainable memory windows after write/erase operations remain unchanged. Retention time characteristics at room temperature for the write and erase states of irradiated and non-irradiated samples reveal that even after an irradiation dose as high as 120 Mrad (SiO2) the devices still exhibit long time charge storage behavior. We observe that the erase state flat-band voltage decay rate does not depend on the irradiation-dose while the opposite happens for the write state flat-band voltage decay rate which is found to be directly dependent on Dit values giving insight to the physics of the discharging mechanisms. 相似文献
10.
Virginie Gueu Hongpeng You Tomokatsu Hayakawa Masayuki Nogami 《Journal of Sol-Gel Science and Technology》2007,41(3):231-236
Fluorescence and spectral hole burning properties of Eu3+ ions were studied in nanocrystals-precipitated SnO2-SiO2 glasses. The glasses were prepared to contain various amount of Eu2O3 using the sol-gel method, in which SnO2 nanocrystals were precipitated by heating in air. In the glasses containing Eu2O3 less than 1%, the Eu3+ ions were preferentially doped in the SnO2 nanocrystals and their fluorescence intensities were enhanced by the energy transfer due to the recombination of electrons
and holes excited in SnO2 crystals. The SnO2 nanocrystals-precipitated glasses exhibited the persistent spectral holes with the depth of ∼25% of the total fluorescence
intensities of the Eu3+ ions. With the increasing Eu2O3 concentration, the amount of SnO2 nanocrystals decreased and the Sn4+ ions formed the random glass structure together with the silica network. This structure change induced the fluorescence intensities
and the hole depth to decrease. 相似文献