Moungi G. Bawendi

Bio: Moungi G. Bawendi is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Quantum dot & Nanocrystal. The author has an hindex of 165, co-authored 626 publications receiving 118108 citations. Previous affiliations of Moungi G. Bawendi include United States Department of the Navy & United States Naval Research Laboratory.

Triplet Exciton Dissociation in Singlet Exciton Fission Photovoltaics

Abstract: Triplet exciton dissociation in singlet exciton fission devices with three classes of acceptors are characterized: fullerenes, perylene diimides, and PbS and PbSe colloidal nanocrystals. Using photocurrent spectroscopy and a magnetic field probe it is found that colloidal PbSe nanocrystals are the most promising acceptors, capable of efficient triplet exciton dissociation and long wavelength absorption.

Semiconductor nanocrystals for inventory control

Abstract: A novel encoding system, compositions for use therein and methods for determining the source, location and/or identity of a particular item or component of interest is provided. In particular, the present invention utilizes a collection of one or more sizes of populations of semiconductor nanocrystals having characteristic spectral emissions, to “track” the source or location of an item of interest or to identify a particular item of interest. The semiconductor nanocrystals used in the inventive compositions can be selected to emit a desired wavelength to produce a characteristic spectral emission in narrow spectral widths, and with a symmetric, nearly Gaussian line shape, by changing the composition and size of the semiconductor nanocrystal. Additionally, the intensity of the emission at a particular characteristic wavelength can also be varied, thus enabling the use of binary or higher order encoding schemes.

Strongly Enhanced Photovoltaic Performance and Defect Physics of Air-Stable Bismuth Oxyiodide (BiOI).

Abstract: R.L.Z.H. thanks Magdalene College, Cambridge. L.C.L. and J.L.M.-D. thank the EPRSC Centre for Doctoral Training: New and Sustainable Photovoltaics, and the Cambridge Winton Programme for the Physics of Sustainability for funding. T.N.H. thanks the Cambridge Graphene Centre, funded by the EPSRC. K.H.L.Z. was supported by the Herschel Smith fellowship. The U.S.-based theory and synthesis portions of this work were supported primarily as part of the Center for Next Generation Materials by Design (CNGMD), an Energy Frontier Research Center funded by the DOE Office of Science, Basic Energy Sciences under Contract No. DE-AC36-08GO28308. The MIT-based characterization portion of this work was supported primarily through a TOTAL SA research grant funded through MITei, as well as a SusChem grant funded by the National Science Foundation (No. CBET-1605495). The TCSPC work was supported as part of the Center for Excitonics, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0001088 (MIT). The computations were performed using resources sponsored by the Department of Energy’s Office of Energy Efficiency and Renewable Energy and located at the NREL. The authors also acknowledge the MRSEC Shared Experimental Facilities at MIT, supported by the National Science Foundation (No. DMF-08019762).

Structure in the lowest absorption feature of CdSe quantum dots

Abstract: We use transient differential absorption experiments to investigate the ‘‘single dot’’ absorption line shape of CdSe quantum dots. We observe both a narrow (full width half maximum ∼5 meV) and a broad (∼50 meV) bleach component within the inhomogeneously broadened first absorption line of our samples. We deduce the single dot absorption line shape which is most consistent with the experimental results. This line shape, which contains structure in the lowest quantum dot absorption feature, explains the large ‘‘Stokes’’ shift seen in the full band edge luminescence of CdSe quantum dots. We discuss the structure within the context of several competing models. The data appear inconsistent with models which use surface states to explain the anomalous emission behavior of II–VI quantum dots. Instead they imply that exciton fine structure is observed in our samples.

Speed Limit for Triplet-Exciton Transfer in Solid-State PbS Nanocrystal-Sensitized Photon Upconversion.

Abstract: Hybrid interfaces combining inorganic and organic materials underpin the operation of many optoelectronic and photocatalytic systems and allow for innovative approaches to photon up- and down-conversion. However, the mechanism of exchange-mediated energy transfer of spin-triplet excitons across these interfaces remains obscure, particularly when both the macroscopic donor and acceptor are composed of many separately interacting nanoscopic moieties. Here, we study the transfer of excitons from colloidal lead sulfide (PbS) nanocrystals to the spin-triplet state of rubrene molecules. By reducing the length of the carboxylic acid ligands on the nanocrystal surface from 18 to 4 carbon atoms, thinning the effective ligand shell from 13 to 6 A, we are able to increase the characteristic transfer rate by an order of magnitude. However, we observe that the energy transfer rate asymptotes for shorter separation distances (≤10 A) which we attribute to the reduced Dexter coupling brought on by the increased effective...

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Semiconductor Clusters, Nanocrystals, and Quantum Dots

Abstract: Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering

Abstract: Optical detection and spectroscopy of single molecules and single nanoparticles have been achieved at room temperature with the use of surface-enhanced Raman scattering. Individual silver colloidal nanoparticles were screened from a large heterogeneous population for special size-dependent properties and were then used to amplify the spectroscopic signatures of adsorbed molecules. For single rhodamine 6G molecules adsorbed on the selected nanoparticles, the intrinsic Raman enhancement factors were on the order of 10 14 to 10 15 , much larger than the ensemble-averaged values derived from conventional measurements. This enormous enhancement leads to vibrational Raman signals that are more intense and more stable than single-molecule fluorescence.