Shuit-Tong Lee

Bio: Shuit-Tong Lee is an academic researcher from Soochow University (Suzhou). The author has contributed to research in topics: Silicon & Nanowire. The author has an hindex of 138, co-authored 1121 publications receiving 77112 citations. Previous affiliations of Shuit-Tong Lee include University of British Columbia & Hong Kong University of Science and Technology.

Molecule design and isomorphism synthesis towards artificial enzymes

Abstract: Design and construction of artificial enzymes via crystal engineering of organic–inorganic hybrid systems having two functional domains; with one domain serving as the reaction active site, and the other providing the reaction driving force have been demonstrated.

Solution-processed inverted polymer solar cells using chemical bath deposited CdS films as electron collecting layer

Abstract: We report the fabrication of a solution-processed cadmium sulfide (CdS) film and its application in inverted polymer solar cells (PSCs). The CdS film is formed by a chemical bath deposition (CBD) process and exhibits an n-type semiconducting property. An efficient inverted PSC is fabricated using a CBD-grown CdS film as the electron collecting layer (ECL), which is inserted between the indium tin oxide (ITO) cathode and the polymer bulk heterojunction active layer. The experimental results reveal that the cell response parameters depend critically on the deposition procedures in terms of bath temperature, deposition time and annealing temperature. A two-fold increase in the overall power conversion efficiency of inverted PSCs is realized with the optimization of CBD-grown CdS film properties through the deposition for 2 h at 50 °C and the annealing treatment at 200 °C. The simple and low-cost deposition method of CdS films is promising for the fabrication of hybrid PSCs.

Organic electroluminescent devices incorporating uv-illuminated fluorocarbon layers

Abstract: A simple and efficient method of increasing conductivity of the fluorocarbon film is disclosed. By illuminating the fluorocarbon film under ultraviolet light (UV-CFx), the film conductivity can be increased by five orders of magnitude. Devices using such a UV-treated, conductive fluorocarbon film as a buffer layer give much better performance in terms of lower operational voltage and enhanced operational stability. The improved smoothness and lowered hole injection barrier height with UV-CFx are responsible for the enhanced performance of electroluminescent devices.

Room temperature solution processed tungsten carbide as an efficient hole extraction layer for organic photovoltaics

Abstract: We demonstrated tungsten carbide (WC) as an efficient anode buffer layer for a high-performance inverted organic solar cell. The devices based on active layers comprised of either poly(3-hexylthiophene) (P3HT) or poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) mixed with fullerene derivatives have achieved power conversion efficiencies (PCEs) of 3.83% and 8.04%, respectively. The WC layer was deposited onto the active layer from a surfactant-free nanoparticle alcohol solution because the buffer layer was well functionalized, removing the requirement for oxygen-plasma or annealing treatment, while simultaneously allowing for optimum photogenerated charge-carrier collection in an inverted structure device. The WC-based device displayed an improved stability performance compared with the MoO3-based one. The anode buffer layer introduced here was easy to implement and compatible with solution processed organic photovoltaics, and therefore applicable for potential cost-effective manufacturing processes.

Effect of negative rf bias on electrophotographic properties of hard diamond-like carbon films deposited on organic photoconductors

Abstract: Hard diamond-like carbon (DLC) films were prepared on organic photoconductor (OPC) and PMMA (polymethyl methacrylate) samples by electron cyclotron resonance (ECR) plasma deposition with low substrate bias. The films exhibited a specific electrical resistivity above and very high transmittance for the visible spectrum of 370-800 nm. The hardness of the OPC samples was increased at least fourfold after deposition of DLC films. The acceptance voltage, photodischarge rate and dark decay rate of the DLC-coated OPC samples were all improved, and reached optimal values for rf biases around . The results indicated that the deposition of hard DLC films on OPC is a very promising technique to lengthen the working lifetimes of the OPC materials.

A roadmap for graphene

Abstract: Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

High-performance lithium battery anodes using silicon nanowires

Abstract: There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

Nanobelts of Semiconducting Oxides

Abstract: Ultralong beltlike (or ribbonlike) nanostructures (so-called nanobelts) were successfully synthesized for semiconducting oxides of zinc, tin, indium, cadmium, and gallium by simply evaporating the desired commercial metal oxide powders at high temperatures. The as-synthesized oxide nanobelts are pure, structurally uniform, and single crystalline, and most of them are free from defects and dislocations. They have a rectanglelike cross section with typical widths of 30 to 300 nanometers, width-to-thickness ratios of 5 to 10, and lengths of up to a few millimeters. The beltlike morphology appears to be a distinctive and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. The nanobelts could be an ideal system for fully understanding dimensionally confined transport phenomena in functional oxides and building functional devices along individual nanobelts.

Raman spectroscopy as a versatile tool for studying the properties of graphene

Abstract: Raman spectroscopy is an integral part of graphene research. It is used to determine the number and orientation of layers, the quality and types of edge, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups. This, in turn, provides insight into all sp(2)-bonded carbon allotropes, because graphene is their fundamental building block. Here we review the state of the art, future directions and open questions in Raman spectroscopy of graphene. We describe essential physical processes whose importance has only recently been recognized, such as the various types of resonance at play, and the role of quantum interference. We update all basic concepts and notations, and propose a terminology that is able to describe any result in literature. We finally highlight the potential of Raman spectroscopy for layered materials other than graphene.

Aggregation-Induced Emission: Together We Shine, United We Soar!

Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China