Showing papers in "Nature Communications in 2012"
TL;DR: It is shown, using first principles calculations, that monolayer molybdenum disulphide is an ideal material for valleytronics, for which valley polarization is achievable via valley-selective circular dichroism arising from its unique symmetry.
Abstract: The monolayer transition-metal dichalcogenide molybdenum disulphide has recently attracted attention owing to its distinctive electronic properties. Cao and co-workers present numerical evidence suggesting that circularly polarized light can preferentially excite a single valley in the band structure of this system.
2,163 citations
TL;DR: This is the first comprehensive investigation of process-friendly multilayer molybdenum disulphide field-effect transistors and their results provide potentially important implications in the fabrication of high-resolution large-area displays and further scientific investigation of various physical properties expected in other layered semiconductors.
Abstract: Unlike graphene, the existence of bandgaps (1–2 eV) in the layered semiconductor molybdenum disulphide, combined with mobility enhancement by dielectric engineering, offers an attractive possibility of using single-layer molybdenum disulphide field-effect transistors in low-power switching devices. However, the complicated process of fabricating single-layer molybdenum disulphide with an additional high-k dielectric layer may significantly limit its compatibility with commercial fabrication. Here we show the first comprehensive investigation of process-friendly multilayer molybdenum disulphide field-effect transistors to demonstrate a compelling case for their applications in thin-film transistors. Our multilayer molybdenum disulphide field-effect transistors exhibited high mobilities (>100 cm2 V−1 s−1), near-ideal subthreshold swings (~70 mV per decade) and robust current saturation over a large voltage window. With simulations based on Shockley's long-channel transistor model and calculations of scattering mechanisms, these results provide potentially important implications in the fabrication of high-resolution large-area displays and further scientific investigation of various physical properties expected in other layered semiconductors. Molybdenum disulphide offers some tantalizing advantages over graphene as a material with which to fabricate field-effect transistors. Kimet al. present a comprehensive study of field-effect transistors made from multilayer samples of MoS2and find that they can achieve high carrier mobilities.
1,494 citations
TL;DR: In this article, the authors presented flexible organic solar cells that are less than 2 μm thick, have very low specific weight and maintain their photovoltaic performance under repeated mechanical deformation.
Abstract: Organic solar cells are promising for technological applications, as they are lightweight and mechanically robust. This study presents flexible organic solar cells that are less than 2 μm thick, have very low specific weight and maintain their photovoltaic performance under repeated mechanical deformation.
1,451 citations
TL;DR: This Article contains errors in the numbering of several papers in the reference list; reference 34 is incorrectly listed as reference 44 and references 35 to 44 are incorrectly list as 34 to 43.
Abstract: Nature Communications 2: Article number: 338 (2011); Published: 7 June 2012; Updated: 25 September 2012. This Article contains errors in the numbering of several papers in the reference list; reference 34 is incorrectly listed as reference 44 and references 35 to 44 are incorrectly listed as 34 to 43.
1,350 citations
TL;DR: A simple adjustment to the traditional lithium-sulphur battery configuration is reported to achieve high capacity with a long cycle life and rapid charge rate and with a significant improvement not only in the active material utilization but also in capacity retention without involving complex synthesis or surface modification.
Abstract: The limitations in the cathode capacity compared with that of the anode have been an impediment to advance the lithium-ion battery technology. The lithium–sulphur system is appealing in this regard, as sulphur exhibits an order of magnitude higher capacity than the currently used cathodes. However, low active material utilization and poor cycle life hinder the practicality of lithium–sulphur batteries. Here we report a simple adjustment to the traditional lithium–sulphur battery configuration to achieve high capacity with a long cycle life and rapid charge rate. With a bifunctional microporous carbon paper between the cathode and separator, we observe a significant improvement not only in the active material utilization but also in capacity retention, without involving complex synthesis or surface modification. The insertion of a microporous carbon interlayer decreases the internal charge transfer resistance and localizes the soluble polysulphide species, facilitating a commercially feasible means of fabricating the lithium–sulphur batteries. The practical performance of lithium sulphide batteries is much less than their predicted performance because redox products dissolve over time. Su and Manthiram show that microporous carbon membranes inserted between cathode and separator localize soluble polysulphide species and improve battery cycling characteristics.
1,289 citations
TL;DR: This work predicts the first material realization of topological crystalline insulator in the semiconductor SnTe by identifying its non-zero topological index and predicts that as a manifestation of this non-trivial topology, SnTe has metallic surface states with an even number of Dirac cones on high-symmetry crystal surfaces.
Abstract: Topologically protected states of matter are receiving widespread attention owing to their unusual electronic properties Using numerical simulations, this study predicts that tin telluride is a physical realization of a new class of materials termed topological crystalline insulators
1,203 citations
TL;DR: Although yields continue to increase in many areas, it is found that across 24-39% of maize-, rice-, wheat- and soybean-growing areas, yields either never improve, stagnate or collapse, which underscores the challenge of meeting increasing global agricultural demands.
Abstract: In the coming decades, continued population growth, rising meat and dairy consumption and expanding biofuel use will dramatically increase the pressure on global agriculture. Even as we face these future burdens, there have been scattered reports of yield stagnation in the world's major cereal crops, including maize, rice and wheat. Here we study data from ∼2.5 million census observations across the globe extending over the period 1961-2008. We examined the trends in crop yields for four key global crops: maize, rice, wheat and soybeans. Although yields continue to increase in many areas, we find that across 24-39% of maize-, rice-, wheat- and soybean-growing areas, yields either never improve, stagnate or collapse. This result underscores the challenge of meeting increasing global agricultural demands. New investments in underperforming regions, as well as strategies to continue increasing yields in the high-performing areas, are required.
1,164 citations
TL;DR: A bubbling method is reported to transfer single graphene grains and graphene films joined from such grains on Pt by ambient-pressure chemical vapour deposition to arbitrary substrate, which is nondestructive not only to graphene, but also to the Pt substrates.
Abstract: Large single-crystal graphene is highly desired and important for the applications of graphene in electronics, as grain boundaries between graphene grains markedly degrade its quality and properties. Here we report the growth of millimetre-sized hexagonal single-crystal graphene and graphene films joined from such grains on Pt by ambient-pressure chemical vapour deposition. We report a bubbling method to transfer these single graphene grains and graphene films to arbitrary substrate, which is nondestructive not only to graphene, but also to the Pt substrates. The Pt substrates can be repeatedly used for graphene growth. The graphene shows high crystal quality with the reported lowest wrinkle height of 0.8 nm and a carrier mobility of greater than 7,100 cm 2 V − 1 s − 1 under ambient conditions. The repeatable growth of graphene with large single-crystal grains on Pt and its nondestructive transfer may enable various applications.
1,092 citations
TL;DR: This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features.
Abstract: Multiple biological structures have demonstrated fog collection abilities, such as beetle backs with bumps and spider silks with periodic spindle-knots and joints. Many Cactaceae species live in arid environments and are extremely drought-tolerant. Here we report that one of the survival systems of the cactus Opuntia microdasys lies in its efficient fog collection system. This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features. The gradient of the Laplace pressure, the gradient of the surface-free energy and multi-function integration endow the cactus with an efficient fog collection system. Investigations of the structure-function relationship in this system may help us to design novel materials and devices to collect water from fog with high efficiencies.
1,051 citations
TL;DR: It is reported that the marriage of graphene chemistry with ice physics can lead to the formation of ultralight and superelastic graphene-based cellular monoliths, which can sustain their structural integrity under a load of >50,000 times their own weight and can rapidly recover from >80% compression.
Abstract: Many applications proposed for graphene require multiple sheets be assembled into a monolithic structure. The ability to maintain structural integrity upon large deformation is essential to ensure a macroscopic material which functions reliably. However, it has remained a great challenge to achieve high elasticity in three-dimensional graphene networks. Here we report that the marriage of graphene chemistry with ice physics can lead to the formation of ultralight and superelastic graphene-based cellular monoliths. Mimicking the hierarchical structure of natural cork, the resulting materials can sustain their structural integrity under a load of >50,000 times their own weight and can rapidly recover from >80% compression. The unique biomimetic hierarchical structure also provides this new class of elastomers with exceptionally high energy absorption capability and good electrical conductivity. The successful synthesis of such fascinating materials paves the way to explore the application of graphene in a self-supporting, structurally adaptive and 3D macroscopic form.
1,047 citations
TL;DR: The authors' membranes with hygro-responsive surfaces can separate, for the first time, a range of different oil-water mixtures in a single-unit operation, with >99.9% separation efficiency, by using the difference in capillary forces acting on the two phases.
Abstract: There is a critical need for new energy-efficient solutions to separate oil-water mixtures, especially those stabilized by surfactants. Traditional membrane-based separation technologies are energy-intensive and limited, either by fouling or by the inability of a single membrane to separate all types of oil-water mixtures. Here we report membranes with hygro-responsive surfaces, which are both superhydrophilic and superoleophobic, in air and under water. Our membranes can separate, for the first time, a range of different oil-water mixtures in a single-unit operation, with >99.9% separation efficiency, by using the difference in capillary forces acting on the two phases. Our separation methodology is solely gravity-driven and consequently is expected to be highly energy-efficient. We anticipate that our separation methodology will have numerous applications, including the clean-up of oil spills, wastewater treatment, fuel purification and the separation of commercially relevant emulsions.
TL;DR: This work presents active optical control of metamaterial-induced transparency through active tuning of the dark mode, and opens up the possibility for designing novel chip-scale ultrafast devices that would find utility in optical buffering and terahertz active filtering.
Abstract: Recently reported metamaterial analogues of electromagnetically induced transparency enable a unique route to endow classical optical structures with aspects of quantum optical systems. This method opens up many fascinating prospects on novel optical components, such as slow light units, highly sensitive sensors and nonlinear devices. In particular, optical control of electromagnetically induced transparency in metamaterials promises essential application opportunities in optical networks and terahertz communications. Here we present active optical control of metamaterial-induced transparency through active tuning of the dark mode. By integrating photoconductive silicon into the metamaterial unit cell, a giant switching of the transparency window occurs under excitation of ultrafast optical pulses, allowing for an optically tunable group delay of the terahertz light. This work opens up the possibility for designing novel chip-scale ultrafast devices that would find utility in optical buffering and terahertz active filtering.
TL;DR: A counter-intuitive dual-polarity flat lens based on helicity-dependent phase discontinuities for circularly polarized light is experimentally demonstrated by controlling the helicity of the input light, and the positive and negative polarity are interchangeable in one identical flat lens.
Abstract: Surface topography and refractive index profile dictate the deterministic functionality of a lens. The polarity of most lenses reported so far, that is, either positive (convex) or negative (concave), depends on the curvatures of the interfaces. Here we experimentally demonstrate a counter-intuitive dual-polarity flat lens based on helicity-dependent phase discontinuities for circularly polarized light. Specifically, by controlling the helicity of the input light, the positive and negative polarity are interchangeable in one identical flat lens. Helicity-controllable real and virtual focal planes, as well as magnified and demagnified imaging, are observed on the same plasmonic lens at visible and near-infrared wavelengths. The plasmonic metalens with dual polarity may empower advanced research and applications in helicity-dependent focusing and imaging devices, angular-momentum-based quantum information processing and integrated nano-optoelectronics.
TL;DR: It is demonstrated that exceptionally efficient broadband modulation of terahertz waves at room temperature can be realized using graphene with extremely low intrinsic signal attenuation, which is also the first demonstrated graphene-based device enabled solely by intraband transitions.
Abstract: Terahertz technology promises myriad applications including imaging, spectroscopy and communications. However, one major bottleneck at present for advancing this field is the lack of efficient devices to manipulate the terahertz electromagnetic waves. Here we demonstrate that exceptionally efficient broadband modulation of terahertz waves at room temperature can be realized using graphene with extremely low intrinsic signal attenuation. We experimentally achieved more than 2.5 times superior modulation than prior broadband intensity modulators, which is also the first demonstrated graphene-based device enabled solely by intraband transitions. The unique advantages of graphene in comparison to conventional semiconductors are the ease of integration and the extraordinary transport properties of holes, which are as good as those of electrons owing to the symmetric conical band structure of graphene. Given recent progress in graphene-based terahertz emitters and detectors, graphene may offer some interesting solutions for terahertz technologies.
TL;DR: The results showed that the new intracellular thermometry could determine an intrinsic relationship between the temperature and organelle function, and not just the spatial and temperature resolutions.
Abstract: Intracellular temperature mapping has not previously been achieved. Now, a fluorescent polymeric thermometer has been developed that can be used in combination with fluorescence-lifetime imaging microscopy to allow thermometry with spatial and temperature resolutions of 200 nm and 0.18–0.58 ° C.
TL;DR: It is found that the filament growth can be dominated by cation transport in the dielectric film, and two different growth modes were observed for the first time in materials with different microstructures.
Abstract: Nanoscale resistive switching devices, sometimes termed memristors, have recently generated significant interest for memory, logic and neuromorphic applications. Resistive switching effects in dielectric-based devices are normally assumed to be caused by conducting filament formation across the electrodes, but the nature of the filaments and their growth dynamics remain controversial. Here we report direct transmission electron microscopy imaging, and structural and compositional analysis of the nanoscale conducting filaments. Through systematic ex-situ and in-situ transmission electron microscopy studies on devices under different programming conditions, we found that the filament growth can be dominated by cation transport in the dielectric film. Unexpectedly, two different growth modes were observed for the first time in materials with different microstructures. Regardless of the growth direction, the narrowest region of the filament was found to be near the dielectric/inert-electrode interface in these devices, suggesting that this region deserves particular attention for continued device optimization.
TL;DR: It is demonstrated that the genus Collinsella was enriched in patients with symptomatic atherosclerosis, defined as stenotic atherosclerotic plaques in the carotid artery leading to cerebrovascular events, whereas Roseburia and Eubacterium were enriched in healthy controls.
Abstract: Recent findings have implicated the gut microbiota as a contributor of metabolic diseases through the modulation of host metabolism and inflammation. Atherosclerosis is associated with lipid accumulation and inflammation in the arterial wall, and bacteria have been suggested as a causative agent of this disease. Here we use shotgun sequencing of the gut metagenome to demonstrate that the genus Collinsella was enriched in patients with symptomatic atherosclerosis, defined as stenotic atherosclerotic plaques in the carotid artery leading to cerebrovascular events, whereas Roseburia and Eubacterium were enriched in healthy controls. Further characterization of the functional capacity of the metagenomes revealed that patient gut metagenomes were enriched in genes encoding peptidoglycan synthesis and depleted in phytoene dehydrogenase; patients also had reduced serum levels of β-carotene. Our findings suggest that the gut metagenome is associated with the inflammatory status of the host and patients with symptomatic atherosclerosis harbor characteristic changes in the gut metagenome.
TL;DR: A new paradigm for the realization of optical metamaterials is introduced, showing that three-dimensional effects may be obtained without complicated inclusions, but instead by tailoring the relative orientation within the lattice.
Abstract: Optical metamaterials are usually based on planarized, complex-shaped, resonant nano-inclusions. Three-dimensional geometries may provide a wider set of functionalities, including broadband chirality to manipulate circular polarization at the nanoscale, but their fabrication becomes challenging as their dimensions get smaller. Here we introduce a new paradigm for the realization of optical metamaterials, showing that three-dimensional effects may be obtained without complicated inclusions, but instead by tailoring the relative orientation within the lattice. We apply this concept to realize planarized, broadband bianisotropic metamaterials as stacked nanorod arrays with a tailored rotational twist. Because of the coupling among closely spaced twisted plasmonic metasurfaces, metamaterials realized with conventional lithography may effectively operate as three-dimensional helical structures with broadband bianisotropic optical response. The proposed concept is also shown to relax alignment requirements common in three-dimensional metamaterial designs. The realized sample constitutes an ultrathin, broadband circular polarizer that may be directly integrated within nanophotonic systems.
TL;DR: It is suggested that substrate-mediated mechanical strain is a ubiquitous phenomenon in two-dimensional materials and the proposed analysis will be of great use in characterizing graphene-based materials and devices.
Abstract: Because of its superior stretchability, graphene exhibits rich structural deformation behaviours and its strain engineering has proven useful in modifying its electronic and magnetic properties. Despite the strain-sensitivity of the Raman G and 2D modes, the optical characterization of the native strain in graphene on silica substrates has been hampered by excess charges interfering with both modes. Here we show that the effects of strain and charges can be optically separated from each other by correlation analysis of the two modes, enabling simple quantification of both. Graphene with in-plane strain randomly occurring between −0.2% and 0.4% undergoes modest compression (−0.3%) and significant hole doping on thermal treatments. This study suggests that substrate-mediated mechanical strain is a ubiquitous phenomenon in two-dimensional materials. The proposed analysis will be of great use in characterizing graphene-based materials and devices. The spectral position of Raman peaks is a useful diagnostic for determining the degree of strain and excess electronic charges present in graphene. This study demonstrates that these two contributions can be separated from each other and therefore be obtained at the same time.
TL;DR: The quantum-corrected model (QCM), a novel approach that incorporates quantum-mechanical effects within a classical electrodynamic framework, is presented, opening a new venue for addressing quantum effects in realistic plasmonic systems.
Abstract: As lengthscales in plasmonic structures enter the sub-nanometre regime, quantum effects become increasingly important. Here, a quantum-corrected model is presented that addresses quantum effects in realistic-sized plasmonic structures, a situation not feasible for full-quantum-mechanical simulations.
TL;DR: Sun et al. as mentioned in this paper synthesize hollow photosynthetic nanospheres that function as light-harvesting antennae and structured scaffolds that improve photoredox catalysis, where the thylakoid membrane acts as a scaffold, precisely arranging functional proteins and electron carriers.
Abstract: Photosynthesis occurs at the thylakoid membrane, which acts as a scaffold, precisely arranging functional proteins and electron carriers. Sun et al. synthesize hollow photosynthetic nanospheres that function as light-harvesting antennae and structured scaffolds that improve photoredox catalysis.
TL;DR: A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared.
Abstract: Reflection is a natural phenomenon that occurs when light passes the interface between materials with different refractive index. In many applications, such as solar cells or photodetectors, reflection is an unwanted loss process. Many ways to reduce reflection from a substrate have been investigated so far, including dielectric interference coatings, surface texturing, adiabatic index matching and scattering from plasmonic nanoparticles. Here we present an entirely new concept that suppresses the reflection of light from a silicon surface over a broad spectral range. A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared. This new antireflection concept relies on the strong forward scattering that occurs when a scattering structure is placed in close proximity to a high-index substrate with a high optical density of states.
TL;DR: A thin-film acoustic metamaterial, comprising an elastic membrane decorated with asymmetric rigid platelets that aims to totally absorb low-frequency airborne sound at selective resonance frequencies ranging from 100-1,000 Hz, can reach almost unity absorption at frequencies where the relevant sound wavelength in air is three orders of magnitude larger than the membrane thickness.
Abstract: The attenuation of low-frequency sound has been a challenging task because the intrinsic dissipation of materials is inherently weak in this regime. Here we present a thin-film acoustic metamaterial, comprising an elastic membrane decorated with asymmetric rigid platelets that aims to totally absorb low-frequency airborne sound at selective resonance frequencies ranging from 100-1,000 Hz. Our samples can reach almost unity absorption at frequencies where the relevant sound wavelength in air is three orders of magnitude larger than the membrane thickness. At resonances, the flapping motion of the rigid platelets leads naturally to large elastic curvature energy density at their perimeter regions. As the flapping motions couple only minimally to the radiation modes, the overall energy density in the membrane can be two-to-three orders of magnitude larger than the incident wave energy density at low frequencies, forming in essence an open cavity.
TL;DR: Near-room-temperature motion of skyrmions driven by electrical currents in a microdevice composed of the helimagnet FeGe, by using in-situ Lorentz transmission electron microscopy is demonstrated.
Abstract: Current-induced motion of magnetic nanostructures, such as skyrmions or domain walls, is envisioned as a promising scalable technology for information storage. Yu et al. demonstrate near-room-temperature motion of skyrmions with current densities orders of magnitude lower than previously reported in domain walls.
TL;DR: Graphene can be printed onto water-soluble silk, which permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel, which is a fully biointerfaced sensing platform, which can be tuned to detect target analytes.
Abstract: Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide-graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets.
TL;DR: Stabilization of a high-temperature phase by crystallization from the glassy state dramatically enhances the Na(+) ion conductivity, and all-solid-state sodium batteries functioned as a rechargeable battery at room temperature.
Abstract: Rechargeable solid-state batteries are promising sources of energy for a range of applications. Hayashi et al. examine the electrochemistry of solid-state sodium batteries, and present an electrolyte that operates at room temperature.
TL;DR: It is shown that a metal-organic frameworks (UTSA-16) displays high uptake of CO(2) at ambient conditions, making it a potentially useful adsorbent material for post-combustion carbon dioxide capture and biogas stream purification.
Abstract: Metal-organic frameworks are promising candidates for capturing and sequestering carbon dioxide. Chen and co-workers report a metal-organic framework that exhibits high uptake of carbon dioxide at ambient conditions, and is a potentially useful adsorbent for post-combustion carbon dioxide capture.
TL;DR: It is shown, using immuno-fluorescent in situ hybridization and ChIP, that up to half of the DNA damage foci in stress-induced senescence are located at telomere irrespective of telomerase activity, and that all persistent foci are associated with telomeres.
Abstract: Telomeres are specialized nucleoprotein structures, which protect chromosome ends and have been implicated in the ageing process. Telomere shortening has been shown to contribute to a persistent DNA damage response (DDR) during replicative senescence, the irreversible loss of division potential of somatic cells. Similarly, persistent DDR foci can be found in stress-induced senescence, although their nature is not understood. Here we show, using immuno-fluorescent in situ hybridization and ChIP, that up to half of the DNA damage foci in stress-induced senescence are located at telomeres irrespective of telomerase activity. Moreover, live-cell imaging experiments reveal that all persistent foci are associated with telomeres. Finally, we report an age-dependent increase in frequencies of telomere-associated foci in gut and liver of mice, occurring irrespectively of telomere length. We conclude that telomeres are important targets for stress in vitro and in vivo and this has important consequences for the ageing process.
TL;DR: It is demonstrated that canonical Wnt signalling is necessary for TGF-β-mediated fibrosis and highlight a key role for the interaction of both pathways in the pathogenesis of fibrotic diseases.
Abstract: The transforming growth factor-β (TGF-β) signalling pathway is a key mediator of fibroblast activation that drives the aberrant synthesis of extracellular matrix in fibrotic diseases. Here we demonstrate a novel link between transforming growth factor-β and the canonical Wnt pathway. TGF-β stimulates canonical Wnt signalling in a p38-dependent manner by decreasing the expression of the Wnt antagonist Dickkopf-1. Tissue samples from human fibrotic diseases show enhanced expression of Wnt proteins and decreased expression of Dickkopf-1. Activation of the canonical Wnt pathway stimulates fibroblasts in vitro and induces fibrosis in vivo. Transgenic overexpression of Dickkopf-1 ameliorates skin fibrosis induced by constitutively active TGF-β receptor type I signalling and also prevents fibrosis in other TGF-β-dependent animal models. These findings demonstrate that canonical Wnt signalling is necessary for TGF-β-mediated fibrosis and highlight a key role for the interaction of both pathways in the pathogenesis of fibrotic diseases.
TL;DR: Ayan variants of green fluorescent protein (CFPs) are widely used as donors in FRET experiments as mentioned in this paper, and a new CFP, mTurquoise2, is developed, which displays a high-fluorescence quantum yield and a long mono-exponential fluorescence lifetime.
Abstract: Cyan variants of green fluorescent protein (CFPs) are widely used as donors in FRET experiments. Here, a new CFP, mTurquoise2, is developed, which displays a high-fluorescence quantum yield and a long mono-exponential fluorescence lifetime.