CuInS2/ZnS核壳结构量子点的水相制备与性能研究

因不含Cd、Pb、Te等有毒元素, 且具有在可见光至近红外光波段可调的发光性能, 铜铟硫(CuInS₂)量子点作为一种新型的I-III-VI型三元半导体材料, 广泛应用于分析检测和生物成像等领域。本研究采用一种低毒低温的方法快速合成CuInS₂量子点及其ZnS核壳结构量子点, 不仅利用ZnS带隙较宽且表面缺陷少的特点, 弥补了CuInS₂量子点的劣势, 提高了CuInS₂量子点的发光性能; 同时由于低毒性ZnS壳层的包覆, 进一步降低生物毒性。当Cu∶In摩尔比为1∶1时, CuInS₂量子点于530 nm处出现明显的发射峰, 且随着In含量的增加, 发光峰逐渐红移。包覆ZnS壳层后, CuInS₂量子点的发光强度明显增大, 且谱峰明显红移。当Cu∶Zn比为1∶1, 回流时间为45 min时, 合成的CuInS₂/ZnS量子点发光性能最优。该合成方法节省能源、生产效率高、绿色环保, 具有较大的应用前景。     

水热法合成N-乙酰-L-半胱氨酸稳定的Cd_xZn_（1-x）Se合金量子点

采用了N-乙酰-L-半胱氨酸为稳定剂,通过水热法制备了荧光发射峰可调、粒径均匀且结晶性能良好的ZnxCd1-xSe合金量子点,并采用紫外-可见光吸收光谱（UV-Vis）、荧光光谱（PL）、X射线衍射（XRD）、高分辨透射电镜（HRTEM）等对其结构和性能进行了表征。重点研究了Cd2＋/Zn2＋比值、初始溶液pH值、水热反应温度和时间等实验条件对ZnxCd1-xSe量子点荧光性能的影响。研究表明所制备的量子点荧光量子产率高（35%）,荧光发射谱半峰宽窄（FWHM〈50nm）,有望作为生物荧光标记物。     

Meyerozyma sp.合成Ag2S量子点及其抗菌性

利用从大庆油田土壤中筛出的耐重金属真菌季也蒙毕赤酵母(Meyerozyma sp.)还原硝酸银和亚硫酸钠合成硫化银(Ag2 S)量子点,并通过X射线光电子能谱分析(XPS)、X射线衍射(XRD)、倒置荧光显微镜、扫描电镜(SEM)对合成的硫化银(Ag2 S)量子点进行表征,同时研究了合成的硫化银(Ag2 S)量子点的抗...     

水解锌制备Zn/ZnO纳米结构及其光学性能研究

利用滚压振动磨在干法室温条件下将金属锌制备成尺度约为3~5nm的锌量子点,并使产物与水蒸气在250℃进行化学反应,得到纳米氧化锌或纳米氧化锌与锌的混合物。分别利用能量发射谱仪(EDS)、透射电镜(TEM)对样品成分和形貌进行了表征。结果表明,250℃反应温度下得到的产物具有良好的分散性,其特征是棒状和片状结构共存,而且纳米棒具有显著的沿[011 1]晶向生长的趋势。室温下光致发光(PL)谱显示,在360nm和388nm处有双紫外发射峰,属于激子态发光,双紫外发射峰可能与掺杂能级有关;同时,在496nm处有蓝光发射峰,在515nm处有绿光发射峰,这两种发射属于表面缺陷态发光。对各种发光峰的发光机制进行了讨论。UV-Vis吸收光谱表明,产物在紫外区有很强的紫外吸收,吸收峰出现了蓝移现象,验证了Zn纳米量子点的掺杂形成掺杂能级,也与测得的可见光发射一致。     

AgInS_2量子点研究进展

Ⅰ-Ⅲ-Ⅵ族新型三元半导体量子点AgInS2,不仅具备了量子点所具有的优异性能,同时以其低毒环保的优点,在近年来取得了重大的研究进展,有望取代Cd系量子点在各领域的应用。通过对国内外最新研究成果进行总结,概述了AgInS2量子点的研究进展,讨论了其存在的问题并对今后的研究进行了展望。     

Ag-SiO2复合纳米颗粒薄膜的制备及其光学特性研究

利用溶胶一凝胶法在玻璃基底上成功制备了Ag—SiO2复合纳米颗粒薄膜,SEM、TEM和XRD的表征分析表明Ag是以单晶纳米颗粒的形态均匀分散在SiO2基质中,形成了多孔状Ag—SiO2复合纳米颗粒薄膜。从Ag—SiO2复合纳米颗粒薄膜的光吸收谱发现,该复合薄膜中鲰纳米颗粒具有较强的等离子共振吸收峰,峰位在430nm附近,随着复合薄膜中Ag、Si摩尔比的逐渐增大,等离子共振吸收峰不断增强且发生蓝移,蓝移量可达30nm;研究Ag—SiO2复合纳米颗粒薄膜的光敛发光特性发现,当激发波长为220nm时,复合薄膜分别在330nm和375nm处出现了两个发光带,随着复合薄膜中Ag、Si摩尔比增大到0．11,两发光带均逐渐增强,继续增加Ag、Si摩尔比,两发光带又逐渐减弱,且375nm处的发光带变化尤为显著。     

水溶性掺杂型CdZnTe量子点的制备及表征

以Zn离子为掺杂材料,L-半胱氨酸为稳定剂,采用高温高压的水热合成法制备出水溶性的掺杂型CdZnTe量子点,有效地减少了量子点表面的缺陷,降低了CdTe量子点的毒性,使得制备出的CdZnTe量子点的生物相容性良好,具有单分散性好、发射范围宽、量子产率高等优点,将会在生化检测及生物医学领域大有作为。     

ZnS/PVA纳米复合薄膜的制备与表征

采用提拉真空干燥的方法制备出以石英玻璃为基板的ZnS/PVA纳米复合薄膜.ZnS/PVA纳米复合溶胶是通过直接混合法将ZnS纳米粒子与聚乙烯醇(PVA)高分子材料水溶液直接混合制备得到.ZnS纳米粒子由微乳液法制备得到.利用透射电子显微镜(TEM)和X射线衍射(XRD)分析表征了ZnS纳米粒子的微观形貌和晶型,TEM结果表明C12H25SH与Zn2 的比例越大,ZnS粒子的粒径越小且在PVA中的分散越好,当C12H25SH/Zn2 的比例为8∶1时,ZnS纳米粒子的粒径为50 nm,呈球状;XRD分析表明,PVA中ZnS纳米粒子具有类似于立方β-ZnS晶相.用紫外-可见(UV-VIS)吸收光谱和荧光光谱(PL)对其光学性能进行了表征,结果表明随着C12H25SH/Zn2 的摩尔比从4:1增长到8:1,ZnS/PVA纳米复合薄膜的吸收峰的强度逐渐增强,峰位也逐渐向短波长方向偏移.在280 nm下激发,PL中出现了峰位位于365 nm处的荧光发射峰;并且发现随着C12H25SH/Zn2 摩尔比从2:1增大到8:1,在C12H25SH/Zn2 摩尔比为4:1时,荧光发射峰的强度相对较大, 其余的荧光发射峰蓝移并且强度增大,表现出较为明显的量子尺寸效应;当C12H25SH/Zn2 摩尔比较大时,出现了低能发光(450 nm～467 nm)的现象.     

含Ag量子点钠硼硅玻璃的三阶非线性光学性质

以正硅酸乙酯、硼酸、金属钠为前驱体采用溶胶-凝胶法合成含Ag量子点的钠硼硅玻璃。X射线粉末衍射 (XRD) 分析Ag量子点具有立方相。通过透射电子显微镜 (TEM) 和高分辨透射电子显微镜 (HRTEM) 测定量子点的尺寸和分布, 结果显示在玻璃中量子点呈规则的球形, 并且尺寸在5~13 nm之间。紫外-可见(UV-Vis)吸收光谱仪得到Ag量子点的表面等离子体共振吸收峰大约在406 nm附近; 利用飞秒Z-scan 技术在800 nm波长处用飞秒钛宝石激光辐照对Ag量子点玻璃的非线性光学性质进行研究, 该玻璃的非线性折射率γ、非线性吸收系数β和三阶非线性极化率χ⁽³⁾分别为 –1.72×10^-17 m²/W、9.96×10^-11 m/W、1.01×10^-11 esu。     

Mn~(2+)掺杂水溶性ZnS量子点的制备及其光致发光性能

采用共沉淀法,在3-巯基丙酸(MPA)为表面修饰剂下,成功制备出Mn2+掺杂水溶性ZnS量子点。利用X射线衍射仪、透射电子显微镜、紫外-可见吸收光谱仪和荧光分光光度计等表征方法研究了Mn2+掺杂剂及掺杂量对ZnS量子点的晶体结构、形貌和发光性能等的影响。结果表明,所得产物为ZnS立方型闪锌矿结构,样品呈不规则球形,粒径主要集中在9.7nm左右;在320nm激发下,Mn2+掺杂ZnS量子点出现两个发射波峰,分别位于587和637nm处,其中587nm处的发射波峰为ZnS表面态缺陷发光,而637nm处的发射波峰则属于Mn2+∶4T1-6A1能级特征发光。同时,利用红外吸收光谱对Mn2+掺杂水溶性ZnS量子点的形成机理进行了初步探讨。     

Preparation of AgInS2 quantum dots and their application for trypsin detection

Journal of Materials Science: Materials in Electronics - Water-soluble AgInS2 quantum dots were prepared by hot injection method using glutathione (GSH) as the stabilizer. The obtained AIS QDs were...     

Synthesis and photoluminescence of ZnS quantum dots

Single-phase zinc sulphide (ZnS) quantum dots were synthesized by a chemical method. The influence of the pH value of the Zn(CH3COO)2 solution on the size and photoluminescence properties of the ZnS quantum dots was evaluated. X-ray power diffraction, transmission electron microscopy, and ultraviolet-visible spectroscopy were used to characterize the structure, size, surface states, and photoluminescence properties of ZnS quantum dots. The results showed that the crystal structure of ZnS quantum dots was a cubic zinc blende structure, and their average diameter was about 3.0 nm. ZnS quantum dots with good distribution and high purity were obtained. A strong broad band centered at about 320 nm was observed in the excitation spectrum of ZnS quantum dots. Their emission spectrum peaking at about 408 nm, was due mostly to the trap-state emission. The relative integrated emission intensity of ZnS quantum dots decreased as the pH value of the Zn(CH3COO)2 solution increased, which could be ascribed to the increase in average diameter of the ZnS quantum dots as the pH value of Zn(CH3COO)2 solution increased.     

Two- and three-photon absorption and frequency upconverted emission of silicon quantum dots

In this communication, we present the experimental results of two- and three-photon excitation studies on silicon quantum dots (QDs) in chloroform (as well as in water) by using femtosecond laser pulses with wavelengths of 778 and 1335 nm and a pulse duration approximately 160 fs. The photoluminescence spectral distributions are nearly the same upon one-, two-, and three-photon excitation. With one- and two-photon excitation, the temporal relaxation measurements of photoluminescence emission manifest the same multiexponential decay behavior in the time range from 0.05 ns to 15 mus, characterized by three successive decay constants: 0.75 ns, 300 ns, and 5 mus, respectively. Finally, the two-photon absorption spectrum in the spectral range of 650-900 nm and the three-photon absorption spectrum in the spectral range of 1150-1400 nm have been measured.     

Studies of interaction of amines with TOPO/TOP capped CdSe quantum dots: Role of crystallite size and oxidation potential

This work reports the interaction of aliphatic (triethyl amine, butyl amine) and aromatic amines (PPD, aniline) with CdSe quantum dots of varied sizes. The emission properties and lifetime values of CdSe quantum dots were found to be dependent on the oxidation potential of amines and crystallite sizes. Smaller CdSe quantum dots (size 5 nm) ensure better surface coverage of amines and hence higher quenching efficiency of amines could be realized as compared to larger CdSe quantum dots (size 14 nm). Heterogeneous quenching of amines due to the presence of accessible and inaccessible set of CdSe fluorophores is indicated. PPD owing to its lowest oxidation potential (0.26 V) has been found to have higher quenching efficiency as compared to other amines TEA and aniline having oxidation potentials 0.66 and >1.0 V, respectively. Butyl amine on the other hand, plays a dual role: its post-addition acts as a quencher for smaller and enhances emission for larger CdSe quantum dots, respectively. The beneficial effect of butyl amine in enhancing emission intensity could be attributed to enhance capping effect and better passivation of surface-traps.     

CdS量子点的制备和光学性质

以醋酸镉、硫粉为原料制备CdS量子点,研究了硫的加入量对其光学性质的影响,结果表明:合成的CdS量子点粒径均匀,分散性较好,随着硫加入量的增加CdS量子点的粒径增大;反应中过量的硫能有效地填补硫空位,从而抑制表面态发光,同时,ODA的修饰也能有效地钝化表面态,减小表面态的发光强度.     

Fluorescent magnetic hybrid nanoprobe for multimodal bioimaging

A fluorescent magnetic hybrid imaging nanoprobe (HINP) was fabricated by the conjugation of superparamagnetic Fe3O4 nanoparticles and visible light emitting (～600 nm) fluorescent CdTe/CdS quantum dots (QDs). The assembly strategy used the covalent linking of the oxidized dextran shell of magnetic particles to the glutathione ligands of QDs. The synthesized HINP formed stable water-soluble colloidal dispersions. The structure and properties of the particles were characterized by transmission electron and atomic force microscopy, energy dispersive x-ray analysis and inductively coupled plasma optical emission spectroscopy, dynamic light scattering analysis, optical absorption and photoluminescence spectroscopy, and fluorescent imaging. The luminescence imaging region of the nanoprobe was extended to the near-infrared (NIR) (～800 nm) by conjugation of the superparamagnetic nanoparticles with synthesized CdHgTe/CdS QDs. Cadmium, mercury based QDs in HINP can be easily replaced by novel water-soluble glutathione stabilized AgInS2/ZnS QDs to present a new class of cadmium-free multimodal imaging agents. The observed NIR photoluminescence of fluorescent magnetic nanocomposites supports their use for bioimaging. The developed HINP provides dual-imaging channels for simultaneous optical and magnetic resonance imaging.     

Detection of bioconjugated quantum dots passivated with different ligands for bio-applications

Bioconjugation of quantum dots has resulted in a significant increase in resolution of biological fluorescent labeling. This intrinsic property of quantum dots can be utilized for sensitive detection of target analytes with high sensitivity; including pathogenic bacteria and cancer monitoring. The quantum dots and quantum dot doped silica nanoparticles exhibit prominent emission peaks when excited at 400 nm but on conjugation to model rabbit antigoat antibodies exhibit diminished intensity of emission peak at 600 nm. It shows that photoluminescence intensity of conjugated quantum dots and quantum dot doped silica nanoparticles could permit the detection of bioconjugation. Samples of conjugated and unconjugated quantum dots and quantum dot doped silica nanoparticles were subjected to enzyme linked immunosorbent assay for further confirmation of bioconjugation. In the present study ligand exchange, bioconjugation, fluorescence detection of bioconjugated quantum dots and quantum dot doped silica nanoparticles and further confirmation of bioconjugation by enzyme linked immunosorbent assay has been described.     

Enhanced emissions of Eu(3+) by energy transfer from ZnO quantum dots embedded in SiO(2) glass

SiO(2):Eu(3+) based bulk composites containing ZnO quantum dots were synthesized by an in situ sol-gel process. The quantum dots homogeneously distributed among the SiO(2) glass matrix exhibited a broad ultraviolet emission band centered at 385?nm. The ZnO ultraviolet luminescence intensity decreased monotonically with increasing Eu(3+) doping concentration, while the Eu(3+) visible emission was intensified significantly by the precipitation of ZnO quantum dots, ascribed to the energy transfer from ZnO to Eu(3+). The Eu(3+) luminescence at 612?nm for the sample with 20?mol% ZnO was about ten times stronger than that for the sample without ZnO. The influence of ZnO or Eu(3+) concentration on the energy transfer process is discussed.     

三色碳点荧光防伪油墨的制备与性能研究

目的 通过优化碳点合成方法和油墨配方,制备一种具有优良防伪效果和印刷适性的环保丝网印刷油墨。方法 以邻苯二胺为碳源,水或乙醇为溶剂,采用溶剂(水)热法制备红色和黄色碳点。以柠檬酸钠和碳酸氢铵为碳源和氮源制备蓝色碳点,并对三色碳点的结构组成和光学性质进行表征和分析。以三色碳点作为荧光颜料,选择乙醇或水作为溶剂,水性环氧树脂或聚丙烯酸树脂作为连接料,通过实验获得最佳配比,制备三色荧光防伪油墨。结果 三色碳点均具有较为均匀的尺寸,在365 nm紫外光激发下分别发射725 nm的红色荧光、450 nm的蓝色荧光和570 nm的黄色荧光,且rCDs、bCDs和yCDs的荧光量子产率分别为56.63%、64.37%和78.26%。通过对pH、细度、黏度等性能测试,该荧光防伪油墨各项印刷适性指标良好。结论 通过优化碳点合成方法可控调节荧光发射光谱,制备出具有较宽的紫外吸收带、较窄的发射光谱带、荧光量子产率高的三色碳点。以此碳点作为荧光颜料可以制备出印刷适性良好的水性油墨,满足荧光防伪印刷的要求。     

Mid-Infrared Emission From InAs Quantum Dots Grown by Metal–Organic Vapor Phase Epitaxy

We have demonstrated mid-infrared emission from the self-assembled InAs quantum dots grown on InP substrate by metal-organic vapor phase epitaxy using low toxic tertiarybutylarsine and tertiarybutylphosphine as group V sources in pure nitrogen ambient. Emission wavelength of the InAs quantum dots has been extended to mid-infrared region by embedding the InAs quantum dots in graded In_xGa_1-xAs matrix layers. When compared with that of the InAs quantum dots grown on lattice matched In_0.53Ga_0.47As/InP matrix, emission wavelength of the InAs quantum dots red shifted by up to 370 nm when embedded the InAs quantum dots in graded In_0.53rarr0.8Ga_0.47rarr0.2As barriers. The longest emission wavelength of >2.35 mum from the self-assembled InAs quantum dot structure has been measured at 77 K. The full-width at half-maximum of the photoluminescence emission spectrum of the InAs quantum dots is as narrow as 25.5 meV. The results achieved would be promising to high performance mid-infrared quantum dot lasers on InP substrate