Raman spectrum of graphene and graphene layers.
TL;DR: This work shows that graphene's electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers, and allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area.
Abstract: Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process The G peak slightly down-shifts This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area
Citations
More filters
TL;DR: The optoelectronic properties of graphene are exploited to realize an ultrafast laser and pave the way to graphene-based photonics.
Abstract: Graphene is at the center of a significant research effort Near-ballistic transport at room temperature and high mobility make it a potential material for nanoelectronics Its electronic and mechanical properties are also ideal for micro- and nanomechanical systems, thin-film transistors, and transparent and conductive composites and electrodes Here we exploit the optoelectronic properties of graphene to realize an ultrafast laser A graphene-polymer composite is fabricated using wet-chemistry techniques Pauli blocking following intense illumination results in saturable absorption, independent of wavelength This is used to passively mode-lock an erbium-doped fiber laser working at 1559 nm, with a 524 nm spectral bandwidth and approximately 460 fs pulse duration, paving the way to graphene-based photonics
1,878 citations
TL;DR: The magnetite-graphene hybrids show a high binding capacity for As(III) and As(V), whose presence in the drinking water in wide areas of South Asia has been a huge problem.
Abstract: Magnetite−graphene hybrids have been synthesized via a chemical reaction with a magnetite particle size of ∼10 nm. The composites are superparamagnetic at room temperature and can be separated by an external magnetic field. As compared to bare magnetite particles, the hybrids show a high binding capacity for As(III) and As(V), whose presence in the drinking water in wide areas of South Asia has been a huge problem. Their high binding capacity is due to the increased adsorption sites in the M−RGO composite which occurs by reducing the aggregation of bare magnetite. Since the composites show near complete (over 99.9%) arsenic removal within 1 ppb, they are practically usable for arsenic separation from water.
1,806 citations
TL;DR: Recent developments in preparation of GQDs are discussed, focusing on the main two approaches (top-down and bottom-down).
1,796 citations
TL;DR: It is reported that the high-temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS(2) thin layers with superior electrical performance on insulating substrates.
Abstract: The two-dimensional layer of molybdenum disulfide (MoS2) has recently attracted much interest due to its direct-gap property and potential applications in optoelectronics and energy harvesting. However, the synthetic approach to obtain high-quality and large-area MoS2 atomic thin layers is still rare. Here we report that the high-temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS2 crystals. This synthetic approach is simple, scalable, and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to arbitrary substrates, providing gr...
1,734 citations
TL;DR: It is found that a nitrogen-doped ordered mesoporous few-layer carbon has a capacitance of 855 farads per gram in aqueous electrolytes and can be bipolarly charged or discharged at a fast, carbon-like speed and can store a specific energy of 41 watt-hours per kilogram (19.5 watt- hours per liter).
Abstract: Carbon-based supercapacitors can provide high electrical power, but they do not have sufficient energy density to directly compete with batteries. We found that a nitrogen-doped ordered mesoporous few-layer carbon has a capacitance of 855 farads per gram in aqueous electrolytes and can be bipolarly charged or discharged at a fast, carbon-like speed. The improvement mostly stems from robust redox reactions at nitrogen-associated defects that transform inert graphene-like layered carbon into an electrochemically active substance without affecting its electric conductivity. These bipolar aqueous-electrolyte electrochemical cells offer power densities and lifetimes similar to those of carbon-based supercapacitors and can store a specific energy of 41 watt-hours per kilogram (19.5 watt-hours per liter).
1,719 citations
References
More filters
28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations