Fluorescent Nanomaterial-derived White Light-Emitting Diodes: What’s Going On Qiang Zhang , Cai-Feng Wang , Lu-Ting Ling and Su Chen * First published online 25 Mar 2014, J. Mater. Chem. C , 2014, 2(22): 4358-4373 链接： http://pubs.rsc.org/en/content/articlelanding/2014/tc/c4tc00048j#!divAbstract 白光LED以长寿命、节能效果显著的优越性能，成为可替代传统白炽灯的新一代照明产品，因此近年来受到广泛关注。文章主要总结了近几年 Prof. Chen 课题组及国际上其他课题组在该领域的一些进展。在前人的基础上，扩充了光转换材料的范围。涉及到的白光LED转换材料主要包括半导体量子点、硅量子点、碳量子点、石墨烯量子点、荧光纳米有机无机和材料（量子点-聚合物、荧光薄膜）等，对此方向上的主要研究进展进行了客观的总结和评述。 1. 量子点 1.1 半导体量子点 1.2 核/多壳结构 1.3 掺杂量子点 1.4 无重金属量子点 1.5 直接白光发射的量子点 2. 碳量子点 3.1 电致发光碳量子点LED 3.2 光致发光碳量子点LED 3.3 白光碳量子点基LED 3. 硅量子点 4. 石墨烯量子点 5. 有机无机杂化白光LED 5.1 量子点-共轭聚合物杂化电致发光WLED 5.2 量子点-聚合物杂化光致发光WLED 5.3 半导体量子点-聚合物荧光薄膜（远程） 5.4 碳量子点-聚合物荧光薄膜（远程） Timeline showing recent progress in fluorescent nanomaterial-derived white LEDs. Abstract: White light-emitting diodes (white LEDs) have recently attracted substantial interest owing to their remarkable energy conservation. The evolution of fluorescent nanomaterials with tunable optical properties has provided an opportunity for light source design of white LEDs. However, the stability and performance of fluorescent nanomaterial-derived white LEDs still fail to meet the requirements of practical applications. It is therefore imperative to boost their overall device performance, which depends on not only the exploitation of advanced fluorescent nanomaterials but also the design of superior light source. In this review, the achievements in fluorescent nanomaterials as color converters towards white LEDs are highlighted, including semiconductor nanocrystals or colloidal quantum dots (QDs), carbon-based nanoparticles, silicon QDs, and organic-inorganic fluorescent nanocomposites. The challenges and future perspectives in this research area are also discussed.
最近，我们在 Chemical Society Reviews 上发表了题为Enhancing solar cell efficiency: the search for luminescent materials as spectral converters 的综述。 http://pubs.rsc.org/en/content/articlelanding/2013/CS/C2CS35288E Photovoltaic (PV) technologies for solar energy conversion represent promising routes to green and renewable energy generation. Despite relevant PV technologies being available for more than half a century, the production of solar energy remains costly, largely owing to low power conversion efficiencies of solar cells. The main difficulty in improving the efficiency of PV energy conversion lies in the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the bandgap of a semiconductor material. In recent years, luminescent materials, which are capable of converting a broad spectrum of light into photons of a particular wavelength, have been synthesized and used to minimize the losses in the solar-cell-based energy conversion process. In this review, we will survey recent progress in the development of spectral converters, with a particular emphasis on lanthanide-based upconversion, quantum-cutting and down-shifting materials, for PV applications. In addition, we will also present technical challenges that arise in developing cost-effective high-performance solar cells based on these luminescent materials. TOC
Quantum Dot Capped Magnetite Nanorings as High Performance Nanoprobe for Multiphoton Fluorescence and Magnetic Resonance Imaging Authors: Hai-Ming Fan,* Malini Olivo, Borys Shuter, Jia-Bao Yi, Ramaswamy Bhuvaneswari, Hui-Ru Tan, Gui-Chuan Xing, Cheng-Teng Ng, Lei Liu, Sasidharan S. Lucky, Boon-Huat Bay, and Jun Ding 期刊 ： J. Am. Chem. Soc . 2010, 132, 1480314811 摘要: In the present study, quantum dot (QD) capped magnetite nanorings (NRs) with a high luminescence and magnetic vortex core have been successfully developed as a new class of magneticfluorescent nanoprobe. Through electrostatic interaction, cationic polyethylenimine (PEI) capped QD have been firmly grafted into negatively charged magnetite NRs modified with citric acid on the surface. The obtained biocompatible multicolor QD capped magnetite NRs exhibit a much stronger magnetic resonance (MR) T2* effect where the r2* relaxivity and r2*/r1 ratio are 4 times and 110 times respectively larger than those of a commercial superparamagnetic iron oxide. The multiphoton fluorescence imaging and cell uptake of QD capped magnetite NRs are also demonstrated using MGH bladder cancer cells. In particular, these QD capped magnetite NRs can escape from endosomes and be released into the cytoplasm. The obtained results from these exploratory experiments suggest that the cell-penetrating QD capped magnetite NRs could be an excellent dual-modality nanoprobe for intracellular imaging and therapeutic applications. This work has shown great potential of the magnetic vortex core based multifunctional nanoparticle as a high performance nanoprobe for biomedical applications. 简评： 氧化铁纳米环的合成和制备已经在前期报道了很多。其特殊的形貌结构导致了稳定涡旋磁态(vortex state)的存在，这个vortex state 在外场的作用下可以磁化转成onion state。涡旋磁态的存在和 两个态之间的transition在过去5年已经在包括Science, PRL 等一系列顶级杂志中发表的论文里进行了详细的讨论。 然后其应用领域尚未有所突破，近期在nature physics上有论文报道关于利用vortex spin有效杀死癌症细胞的例子。本文利用其涡旋磁态时，颗粒之间弱的磁相互作用形成了较稳定的水相分散体，并嫁接了荧光量子点赋予其光学性能。这个复合的纳米环定义为，QD-FVIOs. 其中FVIO is ferrimagnetic/ferromagnetic vortex-state iron oxides.在磁共振成像的表征上发现，相对于超顺磁的氧化铁，涡旋磁态氧化铁表现了非常高的T2*效应。细胞荧光成像实验和MRI成像实验结果表明，这种基于vortex state 的纳米磁环结构在生物医学和细胞成像(cell imaging)上有着很大的用途。详情请参考论文。
In this paper, based on selecting the appropriate type of quantum dots (QDs), a novel method is developed to enhance the quantum yield (QY) of silica-coated QD nanoparticles (SQDNPs). The effect of varying types of QDs on the QY after silica encapsulation is systematically studied. The results show that QDs with appropriate structure and composition of shells can much better retain the initial QY after silanization. The seven-layered shell/core QDs with QY of 47.8% nearly completely retain the original QY and is the best type among six types of QDs for silica modification. In the aspect of shell composition, the CdS plays an important role for QY retention since the lattice mismatch between CdSe and CdS is lower than that of CdSe and ZnS. After the appropriate type of QDs is chosen for silica coating, the highly fluorescent SQDNPs are chemically modified with amine, thiol and carboxyl groups, and then labeled by antibodies for particle-based immunofluorescence assay. The results indicate that the SQDNPsantibody bioconjugates are alternative fluorescent probes useful for biodetection. http://www.iop.org/EJ/abstract/0957-4484/19/46/465604
标签: 量子点
