The 2016 MRS Spring Meeting & Exhibit was held in Phoenix, Arizona earlier this month, with nearly 50 presentations in 20 symposium sessions including graphene-related research. A trend for considering environmentally-friendly methods was apparent throughout the meeting, which, for the growing graphene industry, will continue to be a key concern. These are some of the highlights for graphene.
“Graphene-Based Nanomaterials for Highly Efficient Energy Storage”, Hung-Ju Yen, Hsinhan Tsai, Aiping Chen, Gang Wu, Hsing-Lin Wang. Los Alamos National Laboratory, Los Alamos, New Mexico, United States; Rice University, Houston, Texas, United States; University at Buffalo, the State University of New York, Buffalo, New York, United States.
The authors have demonstrated high-surface area nanomaterials with excellent cyclic durability with enhanced capacity, as novel anode materials in lithium ion batteries. Development of these anodes indicates that the optimal design of graphene materials with high-surface areas and robust structures will be very important for next generation lithium ion batteries with high-energy storage efficiencies.
“Nitrogen-Doped Graphene Nanosheets/Sulfur as Cathode Material for Room-Temperature Sodium-Sulfur Battery”, Yong Hao, Xifei Li, Chunlei Wang. Florida International University, Miami, Florida, United States; Tianjin Normal University, Tianjin, China.
Nitrogen-doped graphene nanosheets interlinked with sulfur were used as an electrode material for room-temperature sodium-sulfur batteries. Synthesized through an environmentally-friendly chemical reaction-deposition strategy, this nanocomposite presented notable cycling life and cycling retention.
“Graphene-Based Optoelectronics for On-Chip Optical Interconnects”, Ren-Jye Shiue, Dirk Englund. Massachusetts Institute of Technology, Cambridge, Massachusetts, United States.
The authors presented implementations of graphene-based electro-optic modulators and photodetectors integrated with silicon photonic integrated circuits. Through coupling graphene to an optical cavity, an efficient electro-optic modulator with a response speed exceeding 1 GHz was demonstrated. Making use of the unique optoelectronic properties of graphene, a new type of on-chip broadband autocorrelator, based on graphene and hexagonal boron nitride heterostructures, was also demonstrated.
“Mid-Infrared Beamsteering with Tunable Graphene-Gold Metasurfaces”, Michelle C Sherrott, Victor Watson Brar, Philip Hon, Luke Sweatlock, Harry A. Atwater. California Inst of Technology, Pasadena, California, United States; Nanophotonics and Metamaterials Laboratory, Northrop Grumman Aerospace Systems, Redondo Beach, California, United States.
In nanophotonics, one of the current hot topics is the realization of dynamic metasurfaces composed of reconfigurable phased arrays of antennas. This would go toward applications including beam-steering and shaping, holography, and optical correlation. To achieve this, a fast active optical component will be required, for spatial control of the phase and amplitude of light in the mid-IR. Graphene is ideal for this, with a highly tunable dielectric constant in this range which varies with charge carrier density, and so can be tuned with an electrostatic gate. The authors demonstrated real-time beam steering by metasurfaces composed of electrically controlled reconfigurable graphene-gold antenna arrays.
“Graphene-Enabled Display Devices on Paper”, Coskun Kocabas. Bilkent Univ, Ankara, Turkey.
This covered a new class of optoelectronic devices on paper, using graphene as an electrically reconfigurable optical medium. While electronic paper has been a popular method for displaying information electronically, its realization has been challenging due to the large surface roughness and incompatible nature of paper with optical materials. This new approach relies on electro-modulation of optical properties of multilayer graphene on paper via blocking the interband electronic transitions. The paper based devices give high optical contrast in the visible spectrum with fast response speed. A wide range of novel optoelectronic devices are opened up, through patterning graphene into multiple pixels, folding paper into 3-dimensional shapes or printing colored ink on paper substrates.
