Franklin Kim

Bio: Franklin Kim is an academic researcher from ShanghaiTech University. The author has contributed to research in topics: Graphene & Nanorod. The author has an hindex of 36, co-authored 51 publications receiving 22925 citations. Previous affiliations of Franklin Kim include University of California, Berkeley & Kyoto University.

Surfactant-free water-processable photoconductive all-carbon composite.

Abstract: Heterojunctions between different graphitic nanostructures, including fullerenes, carbon nanotubes and graphene-based sheets, have attracted significant interest for light to electrical energy conversion. Because of their poor solubility, fabrication of such all-carbon nanocomposites typically involves covalently linking the individual constituents or the extensive surface functionalization to improve their solvent processability for mixing. However, such strategies often deteriorate or contaminate the functional carbon surfaces. Here we report that fullerenes, pristine single walled carbon nanotubes, and graphene oxide sheets can be conveniently coassembled in water to yield a stable colloidal dispersion for thin film processing. After thermal reduction of graphene oxide, a solvent-resistant photoconductive hybrid of fullerene−nanotube−graphene was obtained with on−off ratio of nearly 6 orders of magnitude. Photovoltaic devices made with the all-carbon hybrid as the active layer and an additional fullere...

Chemical synthesis of gold nanowires in acidic solutions.

Abstract: High aspect ratio gold nanowires with single crystalline surface have long been a missing piece in the toolbox of plasmonics metal nanostructures. Such wires are now made with a room temperature, surfactant assisted chemical synthesis in acidic aqueous solution. The diameters and lengths of the multiply twinned gold nanowires can be tuned by varying the amount of seed particles and acid in the growth solution. Nanowires with diameters around 35 nm and lengths up to 10 micron were made with a low seed concentration in pH approximately 1 solution.

Hydration-responsive folding and unfolding in graphene oxide liquid crystal phases

Abstract: Graphene oxide is promising as a plate-like giant molecular building block for the assembly of new carbon materials. Its water dispersibility, liquid crystallinity, and ease of reduction offer advantages over other carbon precursors if its fundamental assembly rules can be identified. This article shows that graphene oxide sheets of known lateral dimension form nematic liquid crystal phases with transition points in agreement with the Onsager hard-plate theory. The liquid crystal phases can be systematically ordered into defined supramolecular patterns using surface anchoring, complex fluid flow, and microconfinement. Graphene oxide is seen to exhibit homeotropic surface anchoring at interfaces driven by excluded volume entropy and by adsorption enthalpy associated with its partially hydrophobic basal planes. Surprisingly, some of the surface-ordered graphene oxide phases dry into graphene oxide solids that undergo a dramatic anisotropic swelling upon rehydration to recover their initial size and shape. T...

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.

Chemistry and properties of nanocrystals of different shapes.

Abstract: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102