Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Graphene and other two-dimensional materials, such as transition metal dichalcogenides, have rapidly established themselves as intriguing building blocks for optoelectronic applications, with a strong focus on various photodetection platforms The versatility of these material systems enables their application in areas including ultrafast and ultrasensitive detection of light in the ultraviolet, visible, infrared and terahertz frequency ranges These detectors can be integrated with other photonic components based on the same material, as well as with silicon photonic and electronic technologies Here, we provide an overview and evaluation of state-of-the-art photodetectors based on graphene, other two-dimensional materials, and hybrid systems based on the combination of different two-dimensional crystals or of two-dimensional crystals and other (nano)materials, such as plasmonic nanoparticles, semiconductors, quantum dots, or their integration with (silicon) waveguides

http://www-g.eng.cam.ac.uk/nms/publications/pdf/nnano.2014.215.pdf

Photodetectors based on graphene, other two-dimensional materials and hybrid systems

Graphene and related two-dimensional crystals and hybrid systems showcase several key properties that can address emerging energy needs, in particular for the ever growing market of portable and wearable energy conversion and storage devices. Graphene's flexibility, large surface area, and chemical stability, combined with its excellent electrical and thermal conductivity, make it promising as a catalyst in fuel and dye-sensitized solar cells. Chemically functionalized graphene can also improve storage and diffusion of ionic species and electric charge in batteries and supercapacitors. Two-dimensional crystals provide optoelectronic and photocatalytic properties complementing those of graphene, enabling the realization of ultrathin-film photovoltaic devices or systems for hydrogen production. Here, we review the use of graphene and related materials for energy conversion and storage, outlining the roadmap for future applications.

Graphene, related two-dimensional crystals, and hybrid systems for energy conversion and storage

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

/pdf/science-and-technology-roadmap-for-graphene-related-two-4q9m7czlkc.pdf

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

https://cyberleninka.org/article/n/768408.pdf

Mechanical properties of graphene and graphene-based nanocomposites

We demonstrate single layer graphene/n-Si Schottky junction solar cells that under AM1.5 illumination exhibit a power conversion efficiency (PCE) of 8.6%. This performance, achieved by doping the graphene with bis(trifluoromethanesulfonyl)amide, exceeds the native (undoped) device performance by a factor of 4.5 and is the highest PCE reported for graphene-based solar cells to date. Current–voltage, capacitance–voltage, and external quantum efficiency measurements show the enhancement to be due to the doping-induced shift in the graphene chemical potential that increases the graphene carrier density (decreasing the cell series resistance) and increases the cell’s built-in potential (increasing the open circuit voltage) both of which improve the solar cell fill factor.

http://absimage.aps.org/image/MAR13/MWS_MAR13-2012-000669.pdf

High Efficiency Graphene Solar Cells by Chemical Doping

Using current-voltage (I-V) and capacitance-voltage (C-V) measurements, we report on the unusual physics and promising technical applications associated with the formation of Schottky barriers at the interface of a one-atom-thick zero-gap semiconductor (graphene) and conventional semiconductors. When chemical vapor deposited graphene is transferred onto n-type Si, GaAs, 4H-SiC and GaN semiconductor substrates, there is a strong van der Waals attraction that is accompanied by charge transfer across the interface and the formation of a rectifying (Schottky) barrier. Thermionic emission theory in conjunction with the Schottky-Mott model within the context of bond-polarization theory provides a surprisingly good description of the electrical properties. Applications, such as to sensors where in forward bias there is exponential sensitivity to changes in the Schottky barrier height due to the presence of absorbates on the graphene or to analogue devices for which Schottky barriers are integral components are promising because of graphene's mechanical stability, its resistance to diffusion, its robustness at high temperatures and its demonstrated capability to embrace multiple functionalities.

Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor Based Diodes

Diodes based on metal-semiconductor interfaces are common place in semiconductor electronics. What happens when the normal metal is replaced by monolayer graphene? A group of physicists at University of Florida experimentally demonstrate that graphene-semiconductor interfaces make interesting diodes for a surprisingly wide variety of semiconductors.

https://link.aps.org/pdf/10.1103/PhysRevX.2.011002

Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor-Based Diodes

http://www.phys.ufl.edu/~afh/reprints/SchottkyDiodes_Carbon.pdf

Tuning Schottky diodes at the many-layer-graphene/ semiconductor interface by doping

We demonstrate single layer graphene/n-Si Schottky junction solar cells that under AM1.5 illumination exhibit a power conversion efficiency (PCE) of 8.6%. This performance, achieved by doping the graphene with bis(trifluoromethanesulfonyl)amide, exceeds the native(undoped) device performance by a factor of 4.5 and the best previously reported PCE in similar devices by a factor of nearly 6. Current-voltage, capacitance-voltage and external quantum efficiency measurements show the enhancement to be due to the doping induced shift in the graphene chemical potential which increases the graphene carrier density (decreasing the cell series resistance) and increases the built-in potential.

Xiaochang Miao

Papers

High Efficiency Graphene Solar Cells by Chemical Doping

Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor Based Diodes

Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor-Based Diodes

Tuning Schottky diodes at the many-layer-graphene/ semiconductor interface by doping

High Efficiency Graphene Solar Cells by Chemical Doping