微观粒子量子谐振动的量子力学表征

对微观粒子量子谐振动的量子尺寸效应进行表征,给出量子谐振子精确的量子哈密顿量,建立适合量子谐振子特性的量子算符代数理论。根据创新的量子谐振子的量子算符代数理论,得到量子谐振子的能量关系。结果表明:量子谐振子的能量为常量,其值与时间量子数无关,不同时间量子态量子谐振子的能量都相同。     

一维量子谐振子坐标和动量的量子统计涨落

:根据一维量子谐振子的湮灭算符和产生算符的实么正变换理论 ,并结合SU(1,1)Lie代数 ,对一维量子谐振子坐标和动量的量子统计涨落进行详细研讨。结果表明 ,在坐标表象中 ,振子动量的量子统计涨落及在动量表象中 ,振子坐标的量子统计涨落均随时间变化     

动力学Monte Carlo方法对量子点生长微观机理模拟的研究进展

为深入理解生长因素及应变对量子点形成的影响,科研工作者采用动力学蒙特卡罗方法对量子点的生长进行了大量研究。简要概括了采用动力学蒙特卡罗法(kinetic monte carlo,KMC)模拟量子点生长的研究进展。主要从模型结构和原子间相互作用势的差异来介绍量子点二维层状生长向三维岛状生长过渡、成核位置、量子点尺寸分布以及量子点形貌转变等内容。此外还简单介绍了图形衬底上有序量子点生长的模拟研究进展,为量子点生长及应用奠定了坚实的基础。     

量子卡诺制冷机制冷率与熵产率的协调优化性能

研究了内可逆谐振子量子卡诺制冷机的整体最优性能。得到了协调优化目标函数Ｅ最大时量子制冷机的制冷系数以及最佳制冷率和熵产率。     

超细颗粒的量子耦合

根据一维量子谐振子的湮灭算符和产生算符为实算符的观点 ,结合SU( 1,1)Lie代数理论 ,对超细颗粒量子耦合系统的能级和波函数进行详细研讨     

通过晶格失配调节有盖层张应变Ge量子点的光电特性

利用Ge与不同衬底形成的不同晶格失配度来调节有盖层的张应变Ge量子点的光电特性。通过有限元方法模拟并获得张应变Ge量子点内的应变分布,而后通过形变势理论和有效质量近似计算得到量子点的电子结构。与无盖层张应变Ge量子点相比,有盖层Ge量子点能保持更大的应变量。另外,随着量子点尺寸和晶格失配度的增大,导带Γ谷与导带L谷的能量差缩减,最终使Ge转变为直接带隙材料。直接带隙能量随着量子点尺寸的增大而减小。该研究结果表明张应变Ge量子点是制备包含激光器在内的Si基光源的理想材料,在未来光电子应用中有巨大潜力。     

透镜形量子点的盖层和高宽比对应变场分布的影响

对透镜形自组织生长量子点的应变分布进行了研究。主要分析了透镜形状的量子点形貌对应变分布的影响,针对开放量子点（无盖层）和非开放量子点（有盖层）情况分别进行了讨论。结果表明,无论有无盖层,横向大尺寸量子点内部的应变分布趋向于均匀,无盖层量子点与有盖层情况相比内部应变释放程度大,甚至在量子点顶部有应变过释放情况,这一现象可以定性解释量子点生长的高度受限、量子点后续生长中出现的量子点塌陷和盖层生长停顿后产生的量子点“挖空”现象。     

量子点/环氧树脂复合材料的制备及性能

通过自组装技术将十二胺包覆到CdSe量子点表面实现量子点的氨基改性,并以三乙烯四胺为固化剂制备得到CdSe量子点/环氧树脂复合材料,研究了量子点表面氨基改性对复合材料性能的影响。通过高分辨透射电镜表征量子点的分散情况及粒径大小,X射线能谱表征量子点改性前后元素的变化,动态光散射表征量子点团簇在环氧基体中的粒度分布,紫外-可见光谱表征复合材料的透明性,荧光光谱表征复合材料的荧光性能,冲击试验表征量子点改性前后对复合材料的增韧作用。结果表明,氨基改性量子点/环氧树脂复合材料的透明度为原始量子点/环氧树脂复合材料的2倍,荧光强度为原始量子点/环氧树脂复合材料的4倍。当量子点含量为0.5%时,氨基改性量子点/环氧树脂复合材料的冲击强度达7.28 k J/m~2。     

衬底温度及退火对液滴外延法生长InAs量子点的影响

研究了In液滴法生长InAs量子点时不同衬底温度,以及是否引入退火的量子点生长情况并建立了物理模型。发现In原子沉积在衬底表面会首先沿[11-0]方向形成条状量子线,由于表面能会趋于最小,量子线会分裂成小段成为量子点的核心,当衬底温度从460℃上升至480℃时,量子点增多的同时量子线减少,且纳米结构的平均高度从4.09nm上升至4.58nm。在衬底温度为480℃的条件下引入退火后,扫描区域内只存在量子点结构,纳米结构平均高度上升至8.56nm。认为In液滴法生长量子点,是一个先形成量子线,量子线再分裂形成量子点的核心,继而捕捉由ES势垒束缚在台阶边缘的原子形成量子点的过程,退火的引入会促进量子线-量子点的转化,提高尺寸均匀性,并由此建立了物理模型。     

碳量子点的氨基化及其对发光性能的影响

利用水热反应釜的条件,使碳量子点的含氧基团与氨水反应,实现了碳量子点的表面氨基化。制备的氨基化碳量子点尺寸分布均匀,总的含氮量受反应温度影响。实验结果表明:氨基化后的碳量子点荧光发射性质明显优于未氨基化的碳量子点;氨基化的氮源及其氮源加入反应过程中的顺序均会影响碳量子点的荧光发射效率。通过实验设计,确定出了氨基化碳量子点的最佳制备条件,从而为碳量子点的光学性质调控及应用奠定了技术支持。     

Spin-density functional approach to N-electron quantum dots within the Matlab pde-tool

The ground-state electronic structures of N-electron quantum dots have been studied by using the spin-density functional method. The calculations are performed in real space using a developed program based on the Matlab pde-tool. Within the program, the recently proposed analytic representation of the exchange–correlation energy functional of Attaccalite et al. is used instead of the most used form of Tanatar and Ceperley. To compare with experimental results and theoretical studies, the addition energy spectra of quantum dots defined by harmonic and anisotropic confinements are examined. The calculations show that when the harmonic confining potential is weak enough the peak in addition energy spectra at N=2 can be firstly disappeared. For geometrical deformed circular quantum dots, the standard shell structure with N=2,6,12,… is continually destroyed, but the slightly distorting does not change the shell-filling order of electrons.     

Labelling of cells with quantum dots

Colloidal quantum dots are semiconductor nanocrystals well dispersed in a solvent. The optical properties of quantum dots, in particular the wavelength of their fluorescence, depend strongly on their size. Because of their reduced tendency to photobleach, colloidal quantum dots are interesting fluorescence probes for all types of labelling studies. In this review we will give an overview on how quantum dots have been used so far in cell biology. In particular we will discuss the biologically relevant properties of quantum dots and focus on four topics: labelling of cellular structures and receptors with quantum dots, incorporation of quantum dots by living cells, tracking the path and the fate of individual cells using quantum dot labels, and quantum dots as contrast agents.     

全无机钙钛矿量子点的光学研究进展

相比于传统半导体量子点,全无机钙钛矿量子点具有发光性能好,发射波长可调,光致发光量子产率高等优点,是光电领域的理想材料,现已被广泛用以制备发光二极管、太阳能电池等光电器件。综述了近年来全无机钙钛矿量子点的研究进展。介绍了全无机钙钛矿量子点的合成方式;分析了离子掺杂和配体修饰对全无机钙钛矿量子点的影响;阐述了全无机钙钛矿量子点在发光二级管中的应用;展望了全无机钙钛矿量子点的未来发展趋势,为全无机钙钛矿量子点在发光二极管的应用提供参考。     

圆偏振光诱导CdTe量子点再生长及其对光致发光的影响

实验研究了以3-巯基丙酸为配体合成的水溶性CdTe量子点经过非偏振光与圆偏振光照射处理后, 量子点的再生长变化规律。采用光致发光谱、紫外-可见吸收光谱、透射电子显微镜与X射线衍射等表征手段分析表明: 非偏振光会促进CdTe量子点的光氧化, 导致量子点尺寸缩小, 荧光发光峰位蓝移, 且发光效率降低; 而圆偏振光增强了配体的光氧化, 在量子点表面形成CdS层, 导致量子点尺寸进一步增大, 荧光发光峰红移, 且发光效率提升。进一步讨论了CdTe量子点与配体之间的键合作用, 相关光化学反应机制及其对量子点光致发光性质的影响。     

有缺陷和无缺陷量子点内应变分布的比较与分析

阐述了量子点内能级结构与应变的关系,用ANSYS7．1计算了有缺陷和无缺陷两种情况下：InAs／GaAs量子点的应变分布,通过对计算结果的比较,讨论了两种情况下不同的应变分布对量子点电子结构影响的不同结果,指出有缺陷时量子点各能级的改变量都与无缺陷时不同,无缺陷时应变的作用只是使能级平行移动;有缺陷时,缺陷将使量子点内能级结构复杂化,有缺陷时发光波长和发光光谱都比无缺陷时复杂。     

过渡金属离子(Mn、Cu、Fe)掺杂半导体纳米晶的研究进展

过渡金属掺杂量子点由于具有零自吸收、更宽的发射光谱范围、更好的光化学稳定性等优点,已经成为提高量子点光电性能的重要研究方向。本文首先简单介绍了其掺杂机制,发光原理,制备方法,然后着重介绍了Mn,Cu,Fe等过渡金属掺杂量子点的最新研究进展。通过对大量相关文献进行总结发现,量子点的量子效率以及发光特性主要受掺杂量子点的制备方法,掺杂浓度,壳层厚度等因素的影响,最后,分析了该领域中目前存在的问题,并提出了今后的研究方向。     

Growth of InAs Quantum Dots on GaAs (511)A Substrates: The Competition between Thermal Dynamics and Kinetics

The growth process of InAs quantum dots grown on GaAs (511)A substrates has been studied by atomic force microscopy. According to the atomic force microscopy studies for quantum dots grown with varying InAs coverage, a noncoherent nucleation of quantum dots is observed. Moreover, due to the long migration length of In atoms, the Ostwald ripening process is aggravated, resulting in the bad uniformity of InAs quantum dots on GaAs (511)A. In order to improve the uniformity of nucleation, the growth rate is increased. By studying the effects of increased growth rates on the growth of InAs quantum dots, it is found that the uniformity of InAs quantum dots is greatly improved as the growth rates increase to 0.14 ML s^?1. However, as the growth rates increase further, the uniformity of InAs quantum dots becomes dual‐mode, which can be attributed to the competition between Ostwald ripening and strain relaxation processes. The results in this work provide insights regarding the competition between thermal dynamical barriers and the growth kinetics in the growth of InAs quantum dots, and give guidance to improve the size uniformity of InAs quantum dots on (N11)A substrates.     

Luminescent quantum dots fluorescence resonance energy transfer-based probes for enzymatic activity and enzyme inhibitors

The paper describes the development and characterization of analytical properties of quantum dot-based probes for enzymatic activity and for screening enzyme inhibitors. The luminescent probes are based on fluorescence resonance energy transfer (FRET) between luminescent quantum dots that serve as donors and rhodamine acceptors that are immobilized to the surface of the quantum dots through peptide linkers. Peptide-coated CdSe/ZnS quantum dots were prepared using a one-step ligand exchange process in which RGDC peptide molecules replace trioctylphosphine oxide (TOPO) molecules as the capping ligands of the quantum dots. The peptide molecules were bound to the surface of the CdSe/ZnS quantum dots through the thiol group of the peptide cysteine residue. The peptide-coated quantum dots were labeled with rhodamine to form the FRET probes. The emission quantum yield of the quantum dot FRET probes was 4-fold lower than the emission quantum yield of TOPO-capped quantum dots. However, the quantum dot FRET probes were sufficiently bright to enable quantitative enzyme and enzyme inhibition assays. The probes were used first to test the enzymatic activity of trypsin in solution based on FRET signal changes of the quantum dot-based enzymatic probes in the presence of proteolytic enzymes. For example, exposure of the quantum dot FRET probes to 500 microg/mL trypsin for 15 min resulted in 60% increase in the photoluminescence of the quantum dots and a corresponding decrease in the emission of the rhodamine molecules. These changes resulted from the release of rhodamine molecules from the surface of the quantum dots due to enzymatic cleavage of the peptide molecules. The quantum dot FRET-based probes were used to monitor the enzymatic activity of trypsin and to screen trypsin inhibitors for their inhibition efficiency.     

硫化铜量子点的研究进展

硫化铜量子点作为一种p型半导体纳米晶,具有很强的表面等离子体共振效应、低的毒性以及独特的光学和电学性能,在光催化、生物技术、光电转换材料领域受到了极大关注。由于单分散的硫化铜量子点的制备过程复杂,效率较低,并且纯的硫化铜量子点电导率较低,这极大地限制了其在能量存储器件方面的应用。此外,由于硫化铜量子点复杂的能带结构和独特的p型半导体特性,针对硫化铜量子点的光学性能调控尚不成熟。基于此,本文综述了硫化铜量子点在制备方面的研究现状与取得的进展,介绍了硫化铜量子点的能带结构、晶体结构,及其在量子点敏化太阳能电池、光催化降解污染物、肿瘤细胞诊断与治疗等方面的研究进展,并对硫化铜量子点或Cu系量子点更进一步的研究、开发应用提出了几点建议。     

AgInS2和Ag—Zn—In—S量子点的制备及表征

采用热注入法成功制备出三元AgInS2和四元Ag—Zn—In—S量子点,物性测试得到AgInS2量子点的发射峰为701nm,Ag—Zn—In—S量子点的发射峰593nm,即Ag-Zn-In—S量子点的发射峰相对于AgInS2量子点发生了蓝移,AgInS2和Ag—Zn—In—S量子点都表现出了较长的荧光寿命,分别为169ns和162ns,结合生物组织光学窗口范围限制,相对Ag—Z—In—S,AgInS2量子点更适用于生物标记。