量子点发光二极管的研究进展

量子点发光技术是近日崛起的一项研究热点,该技术在显示方面的应用价值受到大家的普遍关注,以量子点发光技术为基础的显示器已经出现。量子点发光技术可为显示屏提供更加饱满的色泽,能够提高显示屏的颜色分辨率,有望取代当前主流的OLED技术开创显示科技新阶段。目前研究者对于量子点发光材料做了大量研究,主要分为以下三类:二元非氧化物半导体量子点,钙钛矿结构量子点和碳量子点。本文对上述三类量子点发光材料做了详细的介绍,并对其未来的发展提出展望。     

巯基乙胺为稳定剂制备水溶性荧光量子点的合成探究

本文用巯基乙胺作为稳定剂分别利用了水相加热回流法、水热法两种方法制备出CdTe水溶性荧光量子点。这种荧光量子点可溶于水,且根据其特性可调控发射波长,发光性能较好。同时本文亦研究了在合成CdTe荧光量子点的过程中其反应温度、反应时间,pH环境等对于CdTe量子点发光性能的影响,以此甄选出最优化的量子点合成条件。     

CdSe量子点掺杂硼硅酸盐玻璃的光学性能

将CdO和ZnSe作为量子点引入前驱体,采用高温熔融冷却–热处理法,制备了CdSe量子点掺杂硼硅酸盐玻璃。透射电子显微镜测试表明,CdSe量子点呈六方晶结构。荧光光谱测试表明,CdSe量子点在可见波段存在本征发光和缺陷发光。随热处理温度增高,可以降低缺陷发光,提高量子点本征发光。研究了玻璃网络结构对CdSe量子点析晶影响。结果表明,随着B2O_3含量增大,玻璃中二维(2D)网络结构增多,Cd~(2+)和Se2–移动能力增强,有利于量子点析出和表面缺陷钝化。CdSe量子点波长可调谐发光的特性,使得其有望作为在可见光波段的光增益介质。     

光转换薄膜用碳量子点的合成及其发光性能

开展了光转换薄膜用碳量子点的合成及其发光性能研究,着重探讨了氮(N)源种类对碳量子点发光性能的影响。结果表明,以尿素为N源时,合成出发射峰值位于440～530 nm范围的具有不同颜色特征的碳量子点。而以二乙烯三胺为N源时,合成出发射峰值位于450～460 nm的蓝光N掺杂碳量子点;随着激发波长的增大,碳量子点的发射光谱产生红移。采用不同N源时所合成碳量子点的发光特性差异,主要源于碳量子点晶粒尺寸的不同和表面官能团的化学修饰作用,后者填补了碳量子点的表面缺陷、或使碳量子点的带隙产生了差异,进而导致了不同的发光特性。     

发光碳量子点的合成与毒性

综述了近几年国内外碳量子点的研究现状,对电弧法、激光剥蚀法、电化学法、燃烧-水热法、模板法等合成碳量子点的方法进行了介绍,论述了碳量子点的发光性质及毒性。碳量子点有望取代传统半导体量子点,在生物成像、发光探针分析等领域进行广泛的应用。     

从表层土壤中提取天然碳基量子点

腐殖酸来源于动植物残体的腐殖化反应,在自然环境中广泛分布。因其形成过程与成煤作用类似,很可能与泥炭一样含有大量碳基量子点。碳基量子点由于其量子限域效应和边缘效应,展现出独特的光、电特性,具有良好的荧光和电化学发光性能。从广泛存在的腐殖酸中获取碳基量子点,具有成本低、工艺简单、适合大量生产的优点。本文从表层土壤中提取了腐殖酸,发现其中含有大量的碳基量子点,并对其荧光和电化学发光性质进行研究。     

修饰量子点使其发射白光

<正>研究人员利用两种不同的有机分子修饰硫化锌(Zn S)量子点,使其发射出纯白色的光。这些颗粒提供了一种使量子点发射白光的新方法,并且能够作为目前市场上所用量子点的无毒替代物。量子点是能够发光的半导体纳米晶体,其波长范围较短。电子产品制造商想要使用量子点材料     

量子点的合成及表面修饰

量子点在生物学及生物医学中的应用是当今纳米技术领域中快速发展的研究方向。与传统的有机荧光染料相比,量子点发光的长程稳定性和同时探测多色信号的能力使其在生物成像和生物传感方面具有广泛的应用。概述了量子点的结构及合成方法,并介绍了量子点表面修饰的研究进展。     

酶解木质素水热法制备碳量子点

以玉米秸秆生物发酵剩余物酶解木质素为碳源,选取水热降解的方法制备发光碳量子点,并通过透射电镜(TEM)、紫外-可见光谱仪、荧光光谱仪多种表征方法对样品进行了表征;并且进一步探究了常见金属离子以及溶液环境pH对碳量子点荧光强度的影响。结果显示,其发光碳量子点为分散良好、均一稳定的纳米颗粒,并在紫外灯的激发下发出蓝绿色荧光。     

铜离子掺杂CsPbCl3量子点光学性能及稳定性探究

近年来,钙钛矿因其特殊的结构受到广泛的关注。其中,全无机钙钛矿量子点作为下一代发光材料更因其优异的发光性能得到了广泛的研究和关注。但是因为其本身的铅（Pb）元素带来的毒性和较差的稳定性,钙钛矿量子点在生产和应用方面依然面临着诸多阻碍。为了解决这些难题,介绍了一种铜离子（Cu²⁺）B位掺杂CsPbCl₃钙钛矿量子点。采用了热注射的方法成功地将Cu²⁺引入CsPbCl₃钙钛矿量子点中。研究发现,Cu²⁺掺杂CsPbCl₃量子点能够保持初始四方晶体结构。由于Cu²⁺的掺杂,有效地消除了CsPbCl₃量子点的表面缺陷,从而通过辐射途径促进了激子复合,提高了CsPbCl₃量子点的发光性质。通过稳定性对比测试发现,一段时间内,Cu²⁺掺杂CsPbCl₃量子点在水中的发光强度明显高于CsPbCl₃量子点。     

CdTe/CdS量子点对木犀草素与人血清白蛋白结合力的影响

用还原型谷胱甘肽(GSH)作硫源和稳定剂在水相中合成了生物相容性好、量子产率高的核壳型CdTe/CdS半导体量子点;同时模拟人体内生理环境,研究了CdTe/CdS量子点(QDs)对木犀草素与人血清白蛋白(HSA)相互作用的影响。结果表明,CdTe/CdS QDs可有规律地猝灭HSA荧光;在CdTe/CdS QDs存在条件下,木犀草素可使HSA荧光最大发射波长从341 nm红移到347 nm,红移程度明显大于无QDs存在时,同时木犀草素与HSA的表观结合常数和结合位点数均有增加,即CdTe/CdS QDs使木犀草素与HSA的结合力增强。     

CdS量子点的合成和指纹检测研究

本工作提出以谷胱甘肽(GSH)为修饰试剂合成了高量子产率的硫化镉量子点,并应用其对非渗透性客体玻璃上的潜在指纹进行显现。结果发现,显现出的指纹清晰可辨,且与背景之间的反差好。该方法具有简便、快速、灵敏、安全、经济等特点。     

巯基丙酸还原TeO2水相一步法合成CdTe/ZnTe核壳型量子点

以TeO2为碲源,巯基丙酸（MPA）为稳定剂和还原剂,采用微波辅助加热法一步合成水溶性CdTe/ZnTe核壳结构的半导体量子点.考察了Cd/Zn反应物配比及MPA用量对CdTe/ZnTe量子点性能的影响,并用紫外、荧光光谱、高分辨透射电子显微镜（HRTEM）、X射线粉末衍射（XRD）光谱和EDX电子能谱对CdTe/ZnTe进行了表征.结果表明,在不需要另加NaBH4的条件下,同样能合成水溶性的CdTe/ZnTe量子点,且该核壳结构的CdTe/ZnTe量子点比单一的CdTe量子点具有更高的荧光量子产率.     

CdTe/CdS核壳型量子点的水相合成与荧光性质研究

在水相中制备了不同壳层厚度的核壳型半导体CdTe/CdS量子点,通过荧光光谱(PL)分析、原子力显微镜(AFM)和X-射线粉末衍射 (XRD)光谱分析对产物进行了表征.实验结果表明:反应时间、温度、硫化钠浓度和NaOH的量对CdTe/CdS量子点的壳层厚度和荧光强度都有很大影响.     

CdTe量子点的水相制备

在水相中以巯基丙酸作为稳定剂,合成出具有不同荧光发射波长的CdTe量子点（QDs）,利用紫外吸收光谱（UV）、荧光光谱（FS）以及透射电子显微镜（TEM）对CdTeQDs进行了表征。研究了反应温度及pH值对所制备的CdTeQDs光学性质的影响。实验结果表明,合成CdTeQDs的最佳温度为96℃,pH值为10,且随着时间的增加量子点的粒径增大。     

Enhanced electrochemiluminescence quenching of CdS:Mn nanocrystals by CdTe QDs-doped silica nanoparticles for ultrasensitive detection of thrombin

This work reports an aptasensor for ultrasensitive detection of thrombin based on remarkably efficient energy-transfer induced electrochemiluminescence (ECL) quenching from CdS:Mn nanocrystals (NCs) film to CdTe QDs-doped silica nanoparticles (CdTe/SiO(2) NPs). CdTe/SiO(2) NPs were synthesized via the St?ber method and showed black bodies' strong absorption in a wide spectral range without excitonic emission, which made them excellent ECL quenchers. Within the effective distance of energy scavenging, the ECL quenching efficiency was dependent on the number of CdTe QDs doped into the silica NPs. Using ca. 200 CdTe QDs doped silica NPs on average of 40 nm in diameter as ECL quenching labels, attomolar detection of thrombin was successfully realized. The protein detection involves a competition binding event, based on thrombin replacing CdTe/SiO(2) NPs labeled probing DNA which is hybridized with capturing aptamer immobilized on a CdS:Mn NCs film modified glassy carbon electrode surface by specific aptamer-protein affinity interactions. It results in the displacement of ECL quenching labels from CdS:Mn NCs film and concomitant ECL signal recovery. Owing to the high-content CdTe QDs in silica NP, the increment of ECL intensity (ΔI(ECL)) and the concentration of thrombin showed a double logarithmic linear correlation in the range of 5.0 aM～5.0 fM with a detection limit of 1aM. And, the aptasensor hardly responded to antibody, bovine serum albumin (BSA), haemoglobin (Hb) and lysozyme, showing good detection selectivity for thrombin. This long-distance energy scavenging could have a promising application perspective in the detection of biological recognition events on a molecular level.     

Synthesis of Aqueous CdTe/CdS/ZnS Core/shell/shell Quantum Dots by a Chemical Aerosol Flow Method

This work described a continuous method to synthesize CdTe/CdS/ZnS core/shell/shell quantum dots. In an integrated system by flawlessly combining the chemical aerosol flow system working at high temperature (200–300°C) to generate CdTe/CdS intermediate products and an additional heat-up setup at relatively low temperature to overcoat the ZnS shells, the CdTe/CdS/ZnS multishell structures were realized. The as-synthesized CdTe/CdS/ZnS core/shell/shell quantum dots are characterized by photoluminescence spectra, X-ray diffraction (XRD), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). Fluorescence and XRD results confirm that the obtained quantum dots have a core/shell/shell structure. It shows the highest quantum yield above 45% when compared to the rhodamine 6G. The core/shell/shell QDs were more stable via the oxidation experiment by H₂O₂.     

CdTe量子点的纯化以及作为pH探针的研究

以巯基乙酸为稳定剂在水相中合成了CdTe量子点,并将合成的CdTe量子点进行表征、纯化。通过用0.05 mol.L-1PBS缓冲溶液调节不同的pH来考察量子点的荧光强度和pH的关系。研究发现,水溶性的CdTe量子点是pH敏感的,随着pH值的降低,量子点荧光强度的下降规律与溶液pH值呈现良好的线性关系。结果表明,CdTe量子点是一个令人满意的pH敏感的探针,有潜在的化学和生物传感能力。     

Anodic electrogenerated chemiluminescence of quantum dots: size and stabilizer matter

The electrogenerated chemiluminescence (ECL) of semiconductor quantum dots (QDs) is generally believed to be independent of particle sizes or the capping agents used. Herein, we demonstrate that CdTe QDs with different sizes and stabilizers evidently exhibit different ECL behavior in aqueous solution. The ECL of CdTe QDs stabilized by 3-mercaptopropionic acid (MPA) displays two waves at potentials of about +1.17 V and +1.74 V vs. Ag/AgCl, respectively. ECL spectra confirm that the ECL of QDs is attributed to their band gap luminescence, in which the peak positions are changed with QD sizes. The ECL mechanism of CdTe QDs involves superoxide radical generation by reduction of dissolved oxygen at lower potential or water splitting at higher potential. Direct evidence for superoxide radicals in this medium was obtained via electron spin resonance (ESR) experiments. In comparison, the 2-mercaptoethylamine (MEA)-capped CdTe QDs did not exhibit any ECL in air-saturated pH 7.4 PBS. Both ESR and X-ray photon spectroscopy (XPS) experiments revealed that amine groups in MEA-capped QDs were responsible for the absence of ECL. The reaction of an amine group with a superoxide radical leads to the quenching of ECL. The ECL quenching of MPA-capped CdTe QDs was further used to detect melamine. Under the optimum conditions, the inhibited ECL was linear with the logarithm of concentration of melamine within the concentration range of 10(-9) to 10(-5) M and the detection limit was found to be 6.74 × 10(-10) M, which was 100-100?000 times lower than that of the most previous methods.     

碲化镉量子点与金纳米粒子用于DNA检测

A DNA fluorescence probe system based on fluorescence resonance energy transfer （FRET） from CdTe quantum dot （QD） donors to Au nanoparticle （AuNP） acceptors is presented. CdTe QDs, 2.5nm in diameter, as energy donors, were prepared in water. Au nanoparticles, 16nm in diameter, as energy acceptors, were prepared from gold chloride by reduction. CdTe QDs were linked to 5＇-NH2-DNA through 1-ethyl-3-（dimethylaminopropyl）car- bodiimide hydrochloride （EDC） as a linker, and the 3＇-SH-DNA was self-assembled onto the surface of AuNPs. The hybridization of complementary double stranded DNA （dsDNA） bound to the QDs and AuNPs （CdTe-dsDNA-Au） determined the FRET distance of CdTe QDs and Au nanoparticles. Compared to the fluorescence of CdTe-DNA, the fluorescence of CdTe-DNA-Au conjugates decreased extremely, which indicated that the FRET occurred between CdTe QDs and Au nanoparticles. The fluorescence change of this conjugate depended on the ratio of Au-DNA to CdTe-DNA. When the AuNPs-DNA to QD-DNA ratio was 10：1, the FRET efficiency reached a maximum. The probe system would have a certain degree of fluorescence recovery when a complementary single stranded DNA was introduced into this system, which showed that the distance between CdTe QDs and Au nanoparticles was increased.