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Graphene device makes ultrafast light to energy conversion possible
Using layers of graphene, scientists claim to have created a photodetector that converts light to energy in less than 50 quadrillionths of a second (Image: ICFO/Achim Woessner)
Converting light to electricity is one of the pillars of modern electronics, with the process essential for the operation of everything from solar cells and TV remote control receivers through to laser communications and astronomical telescopes. These devices rely on the swift and effective operation of this technology, especially in scientific equipment, to ensure the most efficient conversion rates possible. In this vein, researchers from the Institute of Photonic Sciences (Institut de Ciències Fotòniques/ICFO) in Barcelona have demonstrated a graphene-based photodetector they claim converts light into electricity in less than 50 quadrillionths of a second.
Graphene has already been identified as a superior substance for the transformation of photons to electrical current, even in the infrared part of the spectrum. However, prior to the ICFO research, it was unclear exactly how fast graphene would react when subjected to ultra-rapid bursts of light energy.
To test the speed of conversion, the ICFO team – in collaboration with scientists from MIT and the University of California, Riverside – utilized an arrangement consisting of graphene film layers set up as a p-n (positive-negative) junction semiconductor, a sub-50 femtosecond, titanium-sapphire, pulse-shaped laser to provide the ultrafast flashes of light, along with an ultra-sensitive pulse detector to capture the speed of conversion to electrical energy.
When this arrangement was fired up and tested, the scientists realized that the photovoltage generation time was occurring at a rate of better than 50 femtoseconds (or 50 quadrillionths of a second).
According to the researchers, this blistering speed of conversion is due to the structure of graphene which allows the exceptionally rapid and effective interaction between all of the conduction band carriers contained within it. In other words, the excitation of the molecules of graphene by the laser pulses causes the electrons in the material to heat up, and stay hot, while the carbon lattice underlying the structure remains cool. And, as the electrons in the laser-excited graphene do not cool down rapidly because they do not easily recouple with the graphene lattice, they remain in that state and transfer their energy much more rapidly.
As such, constant laser-pulse excitation of an area of graphene quickly results in superfast electron distribution within the material at constantly elevated electron temperatures. This rapid conversion to electron heat is then converted into a voltage at the p-n junction of two graphene regions.
Significantly, this "hot-carrier" generation is quite different from the operation of standard semiconductor devices. This is because their operation is dependent upon overcoming of the binding electron energy inherent in the material for an incoming photon to dislodge an electron and create an electrical current. In the ICFO device, the continued excitation of electrons above this band-gap level results in the much faster and easier movement of them when subjected to incoming photons to create an electric current.
Though it is early days in the study of such devices, the practical upshot of this research may be in the eventual production of novel types of ultrafast and extremely effective photodetectors and energy-harvesting devices. And, given that the basic operating principles of hot-carrier graphene devices are substantially different from traditional silicon or germanium semiconductors, an entirely new stream of electronic components that take advantage of this phenomenon may evolve.
The findings of this work have recently been published in the journal Nature Nanotechnology.
Source: ICFO
Source: http://www.gizmag.com/graphene-ultrafast-light-energy-conversion-photodetector-semiconductor/37005/
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Founded by Russian entrepreneur Dmitry Itskov in February 2011 with the participation of leading Russian specialists in the field of neural interfaces, robotics, artificial organs and systems.
The main goals of the 2045 Initiative: the creation and realization of a new strategy for the development of humanity which meets global civilization challenges; the creation of optimale conditions promoting the spiritual enlightenment of humanity; and the realization of a new futuristic reality based on 5 principles: high spirituality, high culture, high ethics, high science and high technologies.
The main science mega-project of the 2045 Initiative aims to create technologies enabling the transfer of a individual’s personality to a more advanced non-biological carrier, and extending life, including to the point of immortality. We devote particular attention to enabling the fullest possible dialogue between the world’s major spiritual traditions, science and society.
A large-scale transformation of humanity, comparable to some of the major spiritual and sci-tech revolutions in history, will require a new strategy. We believe this to be necessary to overcome existing crises, which threaten our planetary habitat and the continued existence of humanity as a species. With the 2045 Initiative, we hope to realize a new strategy for humanity's development, and in so doing, create a more productive, fulfilling, and satisfying future.
The "2045" team is working towards creating an international research center where leading scientists will be engaged in research and development in the fields of anthropomorphic robotics, living systems modeling and brain and consciousness modeling with the goal of transferring one’s individual consciousness to an artificial carrier and achieving cybernetic immortality.
An annual congress "The Global Future 2045" is organized by the Initiative to give platform for discussing mankind's evolutionary strategy based on technologies of cybernetic immortality as well as the possible impact of such technologies on global society, politics and economies of the future.
Future prospects of "2045" Initiative for society
2015-2020
The emergence and widespread use of affordable android "avatars" controlled by a "brain-computer" interface. Coupled with related technologies “avatars’ will give people a number of new features: ability to work in dangerous environments, perform rescue operations, travel in extreme situations etc.
Avatar components will be used in medicine for the rehabilitation of fully or partially disabled patients giving them prosthetic limbs or recover lost senses.
2020-2025
Creation of an autonomous life-support system for the human brain linked to a robot, ‘avatar’, will save people whose body is completely worn out or irreversibly damaged. Any patient with an intact brain will be able to return to a fully functioning bodily life. Such technologies will greatly enlarge the possibility of hybrid bio-electronic devices, thus creating a new IT revolution and will make all kinds of superimpositions of electronic and biological systems possible.
2030-2035
Creation of a computer model of the brain and human consciousness with the subsequent development of means to transfer individual consciousness onto an artificial carrier. This development will profoundly change the world, it will not only give everyone the possibility of cybernetic immortality but will also create a friendly artificial intelligence, expand human capabilities and provide opportunities for ordinary people to restore or modify their own brain multiple times. The final result at this stage can be a real revolution in the understanding of human nature that will completely change the human and technical prospects for humanity.
2045
This is the time when substance-independent minds will receive new bodies with capacities far exceeding those of ordinary humans. A new era for humanity will arrive! Changes will occur in all spheres of human activity – energy generation, transportation, politics, medicine, psychology, sciences, and so on.
Today it is hard to imagine a future when bodies consisting of nanorobots will become affordable and capable of taking any form. It is also hard to imagine body holograms featuring controlled matter. One thing is clear however: humanity, for the first time in its history, will make a fully managed evolutionary transition and eventually become a new species. Moreover, prerequisites for a large-scale expansion into outer space will be created as well.
Key elements of the project in the future
• International social movement
• social network immortal.me
• charitable foundation "Global Future 2045" (Foundation 2045)
• scientific research centre "Immortality"
• business incubator
• University of "Immortality"
• annual award for contribution to the realization of the project of "Immortality”.
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