Congting Sun

Bio: Congting Sun is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Coating & Crystallization. The author has an hindex of 33, co-authored 138 publications receiving 3557 citations. Previous affiliations of Congting Sun include Dalian University of Technology & Kunming Institute of Zoology.

Surface characterization of transparent conductive oxide Al-doped ZnO films

Abstract: High preferred (0 0 2) orientation Al-doped ZnO (ZAO) films were prepared by DC magnetron reactive sputtering from a Zn target mixed with Al of 2.0 wt%. The dependence of spatial distributions of resistivity on substrate temperature indicates that the spatial distribution of resistivity across substrate placed parallel to the target was improved by increasing substrate temperature. XPS analysis indicates Al-enrichment on the film surface.

Crystallization design of MnO2 towards better supercapacitance

Abstract: Nanostructured manganese oxides with different crystallization behaviors were fabricated by a simple redox reaction between KMnO4 and NaNO2 aqueous solution. MnO2 nanostructures with sphere-, rod-, wire-, plate- and flower-like morphologies were crystallized, and the relationship between crystallization characteristics and their electrochemical performances were studied. The electrochemical energy storage behaviors of these samples were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements processed using noncorrosive Na2SO4 as the electrolyte. A maximum specific capacitance 200 F g−1 was obtained for poorly crystallized α-MnO2 at a current density of 1 A g−1. For different crystallographic MnO2 phases, their specific capacitance values increase in the order: β < γ < δ < α, meanwhile, for any particular MnO2 phase, their electrochemical energy storage performances decrease with increasing crystalline nature and particle size.

Structural, electrical, and optical properties of transparent conductive oxide ZnO:Al films prepared by dc magnetron reactive sputtering

Abstract: ZnO:Al/(ZaO) films were deposited on quartz substrates by dc magnetron reactive sputtering from a Zn target mixed with Al. The effect of oxygen flow rate, target to substrate distance, substrate temperature, and Al doping content on the structural, electrical and optical properties of ZAO were investigated. It was observed that the (002) peak position of all films shifts to lower angle comparable to that of bulk ZnO due to the residual stress change with deposition parameters. X-ray photoemission spectroscopy was introduced to analyze the chemical state of Al on the film surface and the results show Al enrichment. The dependences of electrical properties such as resistivity, carrier concentration and Hall mobility on substrate temperature, and Al doping content were measured. The visible transmittance of above 80% and infrared reflectance of above 80% were obtained. The minimum resistivity is 4.23×10−4 Ω cm with the carrier concentration of 9.21×1020 cm−3 and Hall mobility of 16.0 cm2 v1 s−1. The optical ...

Polymorphology formation of Cu2O: A microscopic understanding of single crystal growth from both thermodynamic and kinetic models

Abstract: Cuprous oxide (Cu2O) crystals with polymorphology have been synthesized under EDTA-assisted hydrothermal conditions. It was found that the branching degree of Cu2O cubes can be kinetically controlled by different reaction times, which can evolve into five typical polyhedra by selecting different reagent amounts and pH values. On the basis of chemical bonding viewpoint, a kinetic model has been proposed to explain the polymorphology formation of Cu2O crystals. Our calculated results indicate that octahedron is the thermodynamic shape of Cu2O crystal, while these five typical shapes can be kinetically simulated. Furthermore, the current kinetic model can be used to understand the growth mechanism of other inorganic crystals grown in the presence of additives.

Transparent conductive ZnO:Al thin films deposited on flexible substrates prepared by direct current magnetron sputtering

Abstract: In this paper, we report different methods to reduce the sheet resistance of ZnO:Al (AZO) films on flexible substrates without degrading the optical transmittance in the visible range. Under proper bias, AZO films deposited on Al2O3-buffered flexible substrates showed a significant decrease of sheet resistance when compared with those deposited on bare polymer. The films with resistivity as low as 8.4 � 10 � 4 V cm and the optical transmittance about 80% have been obtained by improved methods. By calculating the Al doping efficiency and the mean free path of electrons, ionized impurity scattering was considered to be the dominant factor for the transport mechanism of carriers. D 2005 Elsevier B.V. All rights reserved.

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

X-ray photoelectron spectroscopy: Towards reliable binding energy referencing

Abstract: With more than 9000 papers published annually, X-ray photoelectron spectroscopy (XPS) is an indispensable technique in modern surface and materials science for the determination of chemical bonding. The accuracy of chemical-state determination relies, however, on a trustworthy calibration of the binding energy (BE) scale, which is a nontrivial task due to the lack of an internal BE reference. One approach, proposed in the early days of XPS, employs the C 1s spectra of an adventitious carbon layer, which is present on all surfaces exposed to air. Despite accumulating criticism, pointing to the unknown origin and composition of the adventitious carbon, this is by far the most commonly used method today for all types of samples, not necessarily electrically insulating. Alarmingly, as revealed by our survey of recent XPS literature, the calibration procedure based on the C 1s peak of adventitious carbon is highly arbitrary, which results in incorrect spectral interpretation, contradictory results, and generates a large spread in reported BE values for elements even present in the same chemical state. The purpose of this review is to critically evaluate the status quo of XPS with a historical perspective, provide the technique’s operating principles, resolve myths associated with C 1s referencing, and offer a comprehensive account of recent findings. Owing to the huge volume of XPS literature produced each year, the consequences of improper referencing are dramatic. Our intention is to promote awareness within a growing XPS community as to the problems reported over the last six decades and present a guide with best practice for using the C 1s BE referencing method.

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

Abstract: It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.

Electrochromics for smart windows: Oxide-based thin films and devices

Abstract: Electrochromic (EC) smart windows are able to vary their throughput of visible light and solar energy by the application of an electrical voltage and are able to provide energy efficiency and indoor comfort in buildings Section 1 explains why this technology is important and timely by first outlining today's precarious situation concerning increasing energy use and associated effects on the world's climate, and this section also underscores the great importance of enhancing the energy efficiency of buildings by letting them function more in harmony with the environment—particularly its varying temperature—than is possible with current mainstream technologies This same chapter also surveys recent work on the energy savings and other benefits that are possible with EC-based technologies Section 2 then provides some notes on the history of the EC effect and its applications Section 3 presents a generic design for the oxide-based EC devices that are most in focus for present-day applications and research This design includes five superimposed layers with a centrally-positioned electrolyte connecting two oxide films—at least one of which having EC properties—and with transparent electrical conductors surrounding the three-layer structure in the middle It is emphasized that this construction can be viewed as a thin-film electrical battery whose charging state is manifested as optical absorption Also discussed are six well known hurdles for the implementation of these EC devices, as well as a number of practical constructions of EC-based smart windows Section 4 is an in-depth discussion of various aspects of EC oxides It begins with a literature survey for 2007–2013, which updates earlier reviews, and is followed by a general discussion of optical and electronic effects and, specifically, on charge transfer absorption in tungsten oxide Ionic effects are then treated with foci on the inherent nanoporosity of the important EC oxides and on the possibilities to accomplish further porosity by having suitable thin-film deposition parameters A number of examples on the importance of the detailed deposition conditions are presented, and Section 4 ends with a presentation of the EC properties of films with compositions across the full tungsten–nickel oxide system Section 5 is devoted to transparent electrical conductors and electrolytes, both of which are necessary in EC devices Detailed surveys are given of transparent conductors comprising doped-oxide semiconductors, coinage metals, nanowire meshes and other alternatives, and also of electrolytes based on thin films and on polymers Particular attention is devoted to electrolyte functionalization by nanoparticles Section 6 considers one particular device construction: A foil that is suitable for glass lamination and which, in the author's view, holds particular promise for low-cost large-area implementation of EC smart windows Device data are presented, and a discussion is given of quality assessment by use of 1/ f noise The “battery-type” EC device covered in the major part of this critical review is not the only alternative, and Section 7 consists of brief discussions of a number of more or less advanced alternatives such as metal hydrides, suspended particle devices, polymer-dispersed liquid crystals, reversible electroplating, and plasmonic electrochromism based on transparent conducting oxide nanoparticles Finally, Section 8 provides a brief summary and outlook The aim of this critical review is not only to paint a picture of the state-of-the-art for electrochromics and its applications in smart windows, but also to provide ample references to current literature of particular relevance and thereby, hopefully, an easy entrance to the research field

MnO2-based nanostructures for high-performance supercapacitors

Abstract: MnO2-based materials have been intensively investigated for use in pseudocapacitors due to their high theoretical specific capacitance, good chemical and thermal stability, natural abundance, environmental benignity and low cost. In this review, several main factors that affect the electrochemical properties of MnO2-based electrodes are presented. Various strategic design and synthetic methods of MnO2-based electrode materials for enhanced electrochemical performance are highlighted and summarized. Finally, the challenges and future directions toward the development of MnO2-based nanostructured electrode materials for high performance supercapacitors (SCs) are discussed.