Yan Wang

Bio: Yan Wang is an academic researcher from Nankai University. The author has contributed to research in topics: Graphene & Carbon nanotube. The author has an hindex of 14, co-authored 24 publications receiving 8006 citations. Previous affiliations of Yan Wang include Tianjin University.

Photoconductivity of Bulk‐Film‐Based Graphene Sheets

Abstract: Time-resolved photoconductivity measurements are carried out on graphene films prepared by using soluble graphene oxide. High photocurrent generation efficiency is observed for these graphene-based films, and the relationships between their photoconductivity and different preparation methods, incident light intensity, external electric field, and photon energies are investigated. Higher photoconductivity is observed with higher photon energy at same incident light intensity. By fitting the experimental data to the Onsager model, the primary quantum yields for charge separation to generate bound electron‐hole pairs and the initial ion-pair thermalization separation distance are calculated.

Mono-layer graphite and polymer compound material and preparation and application thereof

Abstract: The invention relates to a composite material of monolayer graphite and polymers, as well as a preparation method thereof. The composite material takes the monolayer graphite and the polymers as raw materials which are well mixed, wherein the weight portions of the raw materials are: 0.1 to 100 portions of the monolayer graphite and 0.1 to 100 portions of the polymers or other matrix materials. The preparation method is characterized by utilizing the excellent conductivity and large length-diameter ratio of the monolayer graphite to prepare conducting composite materials. Micro analysis proves that the monolayer graphite evenly disperses in the matrix materials, and a conducting network can be formed only by adding a small amount of the monolayer graphite, so as to obtain the conducting composite material with a plurality of forms. The composite material simultaneously has high strength and modulus, and is used in building, mechanical, aerospace and other special environments. In addition, as the monolayer graphite has excellent heat-conducting property, the composite material has the advantages of heat dissipation convenience and the like, and is expected to be applied to the precision instrument, microelectronic and other fields.

Electrode material and capacitor

Abstract: An electrode material comprising 0.5-50 wt % functionalized graphene material and a capacitor comprising the electrode material are provided. A method for preparing the functionalized graphene material is also provided. The method comprises the step of chemically reducing the soluble graphene material and the step of physically reducing the chemically reduced graphene material.

The chemistry of graphene oxide

Abstract: The chemistry of graphene oxide is discussed in this critical review Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)

Graphene and Graphene Oxide: Synthesis, Properties, and Applications

Abstract: There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.

Graphene photonics and optoelectronics

Abstract: The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.

Carbon-based Supercapacitors Produced by Activation of Graphene

Abstract: Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp 2 -bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...