CdSe与CdSe/ZnS量子点合成及稀土掺杂

在LSS(liquid-solid-solution)多相体系中制得了CdSe、CdSe/ZnS量子点和Eu掺杂的量子点。利用TEM、XRD、PL、EDS对产物进行了表征。TEM结果显示所得的量子点形貌规则、尺寸均匀。XRD结果显示CdSe/ZnS量子点呈六方晶系。PL结果对比表明,合适厚度壳层ZnS包覆后的CdSe量子点发光效率明显提高,发光峰的半高宽有大幅度提高,并分析了所得的结果。掺杂稀土元素Eu后,CdSe(Eu)量子点在红光区域产生了新的发光峰;而CdSe(Eu)/ZnS量子点在红光区域内没有出现发光峰,并阐明了这种现象的原因。     

石墨烯量子点/CdS/CdSe共敏化太阳能电池

以三维锐钛矿TiO₂微球为上层光散射层材料, 以商业纳米TiO₂为下层连接材料, 采用刮刀法制备了一种新颖的双层TiO₂薄膜, 并应用于量子点敏化太阳能电池(QDSSC)。其中, 石墨烯量子点(GQDs)采用滴液法引入, CdS/CdSe量子点采用连续离子层吸附法(SILAR)制备。采用场发射扫描电镜、透射电镜、X射线衍射、紫外-可见漫反射光谱及荧光光谱对样品进行表征。实验还制备了CdS/CdSe量子点敏化及石墨烯量子点/CdS/CdSe共敏化太阳能电池, 并研究了石墨烯量子点及CdS不同敏化周期及对电池性能影响。研究结果表明, 石墨烯量子点及CdS不同敏化周期对薄膜的光学性质、电子传输及载流子复合均有较大影响。优选条件下, TiO₂/QGDs/CdS(4)/CdSe电池的光电转换效率为1.24%, 光电流密度为9.47 mA/cm², 显著高于TiO₂/CdS(4)/CdSe电池的这些参数(0.59%与6.22 mA/cm²)。这主要是由于TiO₂表层吸附石墨烯量子点后增强了电子的传输, 减少了载流子的复合。     

CdSe胶质量子点的电致发光特性研究

采用胶体化学法合成硒化镉(CdSe)胶质量子点, 在此基础上制成了以CdSe胶质量子点为有源层, 结构为ITO/ZnS/CdSe/ZnS/Al的电致发光(EL)器件. 透射电镜测量表明量子点的尺寸为4.3 nm, 扫描电子显微镜测量ZnS薄膜和Al薄膜结果显示表面均较为平整, 由器件结构的X射线衍射分析观察到了CdSe(111)、ZnS(111)等晶面的衍射, 表明器件中包含了CdSe量子点和ZnS绝缘层材料. 光致发光谱表征胶质量子点的室温发光峰位于614 nm, 电致发光测量得到器件在室温下的发光波长位于450 ~ 850 nm, 峰值在800 nm附近. 本文对电致发光机制及其与光致发光谱的区别进行了讨论.     

微混合模块合成CdS量子点方法研究

以CdS量子点的合成为考察对象,分别使用梳型和级联两种混合模块搭建了连续操作的微反应系统,比较了两种模块的混合效果,通过优化前躯体流速和停留时间获得了理想的合成工艺,使得量子点的尺寸分布极窄。     

在多相体系中制备核壳型CdSe/ZnS量子点

在多相体系中制得了CdSe/ZnS半导体量子点,采用X射线粉末衍射(XRD)、电子透射显微镜(TEM)等测试手段对产物进行了表征,结果表明CaSe/CdS量子点尺寸均一、形貌规则,具有立方晶体结构.初步研究了此体系的反应机理,并通过紫外-可见吸收光谱和荧光光谱对产物的光学性质进行了分析,结果表明在CASe量子点外面包覆一定厚度的ZnS壳层后,其激子发射强度和量子效率显著提高.     

CdSe量子点的合成、功能化及生物应用

量子点是一种新型荧光纳米材料,具有独特而优良的荧光性质,近年来受到研究者的广泛关注。文章综述蛋白质、抗体、肽类以及DNA等对CdSe量子点(CdSe QDs)的表面功能化作用,以及CdSe QDs在生物传感分析中的重要研究进展。具体介绍CdSe量子点的多种合成方法(包括有机相合成、水相合成等),蛋白质、抗体、肽类、DNA利用共价键或静电作用对CdSe量子点修饰方法,以及其在生物医学标记与成像、生物传感、药物载送以及癌症治疗等领域的相关应用,最后针对现有研究的不足进行展望。希望通过对CdSe量子点全方位总结与概述,在一定程度上帮助科研工作者快速、准确了解其相关性质与研究进展。     

羧基CdSe荧光量子点的制备及其荧光特性研究

以氯化镉、硒粉为前驱体,巯基乙酸(TGA)为稳定剂,制备了羧基CdSe量子点,并研究了其荧光特性与影响因素。结果表明,反应温度、反应时间与反应体系的pH值是影响量子点生长和荧光性能的主要因素。制备羧基CdSe量子点的最优条件为反应温度90℃、pH=11、n(Cd)∶n(Se)=2∶1。制备的羧基CdSe量子点的粒径随反应时间的延长而逐渐增大,量子点荧光稳定性好,荧光强度高,光漂白时间延长。     

量子点微显示技术研究进展

量子点是一种具有量子限域效应的半导体纳米晶,近年来,以其优异的光电特性得到了广泛关注。量子点具有发光效率高、发光波长可调、发光半峰宽窄、可溶液法低成本制备等优势,已被大量应用于显示领域,成为了新型显示的核心材料之一。微显示技术一般应用于有效显示区域对角线长度小于1 inch的近眼显示场景中,近年来虚拟现实、增强现实等近眼显示场景的兴起,对高亮度、高像素密度、全彩色的微显示技术提出了更高的要求。本文将从量子点应用于高亮度、高像素密度的全彩微显示技术的角度出发,从光致发光和电致发光两条技术路线对现有的进展进行回顾和总结,最后对量子点应用于微显示技术面临的机遇和挑战进行展望。     

电泳沉积法制备纳米CdSe均匀膜

采用电泳沉积技术，在预处理好的片上交替沉积表面带正负电荷的CdSe薄膜，扫描电子显微镜、原子力显微镜和紫外一可见光谱的表征分析表明，薄膜中粒子排布紧密平整、粒径大小均匀、颗粒粒径在60-100nm范围，构成的type—II型半导体材料发生电子空穴分离，量子点的荧光发射强度减小。     

Voltage-Controlled Electron-Hole Interaction in a Single Quantum Dot

The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole exchange interaction depends on the exciton charge and demonstrate how the interaction can be switched on and off with a small dc voltage. Furthermore, we report polarization sensitive analysis of the excitonic interband transition in a single quantum dot as a function of charge with and without magnetic field.     

Stability of Quantum Dots,Quantum Dot Films,and Quantum Dot Light‐Emitting Diodes for Display Applications

Quantum dots (QDs) are being highlighted in display applications for their excellent optical properties, including tunable bandgaps, narrow emission bandwidth, and high efficiency. However, issues with their stability must be overcome to achieve the next level of development. QDs are utilized in display applications for their photoluminescence (PL) and electroluminescence. The PL characteristics of QDs are applied to display or lighting applications in the form of color‐conversion QD films, and the electroluminescence of QDs is utilized in quantum dot light‐emitting diodes (QLEDs). Studies on the stability of QDs and QD devices in display applications are reviewed herein. QDs can be degraded by oxygen, water, thermal heating, and UV exposure. Various approaches have been developed to protect QDs from degradation by controlling the composition of their shells and ligands. Phosphorescent QDs have been protected by bulky ligands, physical incorporation in polymer matrices, and covalent bonding with polymer matrices. The stability of electroluminescent QLEDs can be enhanced by using inorganic charge transport layers and by improving charge balance. As understanding of the degradation mechanisms of QDs increases and more stable QDs and display devices are developed, QDs are expected to play critical roles in advanced display applications.     

喷墨打印量子点薄膜制备的影响因素研究

目的 为了通过喷墨打印技术很好地实现量子点薄膜图案化,需要调节量子点薄膜制备工艺的各项参数以获得表面均匀、厚度适宜和无咖啡环结构的量子点薄膜。方法 基板和退火是影响量子点薄膜成膜性能的2个重要参数,分别研究基板的清洗、材料和温度以及退火的温度和时间对喷墨打印量子点薄膜成膜性能的影响。结果 选择3种不同类型的溶剂依次清洗可提高基板表面能,有利于墨水的铺展;PVK基板的量子点面薄膜形貌相较于Pedot:Pss更均匀;当基板温度为50 ℃、退火温度为80 ℃或90 ℃、退火时间为15 min时,咖啡环效应最弱,可获得表面均匀、厚度适宜和无咖啡环结构的量子点薄膜。结论 基板的清洗、自身材料以及温度都会影响墨水的铺展性能,从而影响量子点薄膜的成膜性能;控制退火温度与退火时间,以使马兰戈尼流起作用,咖啡环效应被明显抑制,可以获得表面均匀的量子点薄膜。     

量子点量子阱ZnS/HgS/ZnS/CdS的制备与光学特性

运用湿化学与表面化学方法制备了ＺｎＳ／ＨｇＳ／ＺｎＳ／Ｃｄｓ量子点量子阱（ＱＤＱＷ）结构,以吸收光谱、光致发光及激光谱表征该结构,并研究了外层ＣｄＳ对材料发光特性的影响,首次观测到ＣｄＳ对中间ＨｇＳ阱层发光的增强作用,并归因子隧道效应的存在。     

Synthesis of Inorganic–Organic 2D CdSe Slab‐Diamine Quantum Nets

Porous semiconductors attract great interest due to their unique structural characteristics of high surface area as well as their intrinsic optical and electronic properties. In this study, synthesis of inorganic–organic 2D CdSe slabs‐diaminooctane (DAO) porous quantum net structures is demonstrated. It is found that the hybrid 2D CdSe‐DAO lamellar structures are disintegrated into porous net structures, maintaining an ultrathin thickness of ≈1 nm in CdSe slabs. Furthermore, the CdSe slabs in quantum nets show the highly shifted excitonic transition in the absorption spectrum, demonstrating their strongly confined electronic structures. The possible formation mechanism of this porous structure is investigated with the control experiments of the synthesis using n‐alkyldiamines with various hydrocarbon chain lengths and ligand exchange of DAO with oleylamine. It is suggested that a strong van der Waals interaction among long chain DAO may exert strong tensile stress on the CdSe slabs, eventually disintegrating slabs. The thermal decomposition of CdSe‐DAO quantum nets is further studied to form well‐defined CdSe nanorods. It is believed that the current CdSe‐DAO quantum nets will offer a new type of porous semiconductors nanostructures under a strong quantum‐confinement regime, which can be applied to various technological areas of catalysts, electronics, and optoelectronics.