探花直播 of Cambridge - organic

Quantum waves at the heart of organic solar cells

fpjl2 — Thu, 12 Dec 2013 19:01:00 +0000

By using an ultrafast camera, scientists say they have observed the very first instants following the absorption of light into artificial yet organic nanostructures and found that charges not only formed rapidly but also separated very quickly over long distances - phenomena that occur due to the wavelike nature of electrons which are governed by fundamental laws of quantum mechanics.

This result surprised scientists as such phenomena were believed to be limited to "perfect" - and expensive - inorganic structures; rather than the soft, flexible organic material believed by many to be the key to cheap, 'roll-to-roll' solar cells that could be printed at room temperatures - a very different world from the traditional but costly processing of current silicon technologies.

探花直播study, published today in the journal Science, sheds new light on the mystery mechanism that allows positive and negative charges to be separated efficiently - a critical question that continues to puzzle scientists - and takes researchers a step closer to effectively mimicking the highly efficient ability to harvest sunlight and convert into energy, namely photosynthesis, which the natural world evolved over the course of millennia.

"This is a very surprising result. Such quantum phenomena are usually confined to perfect crystals of inorganic semiconductors, and one does not expect to see such effects in organic molecules - which are very disordered and tend to resemble a plate of cooked spaghetti rather than a crystal," said Dr Simon G茅linas, from Cambridge's Cavendish Laboratory, who led the research with colleagues from Cambridge as well as the 探花直播 of California in Santa Barbara.

During the first few femtoseconds (one millionth of one billionth of a second) each charge spreads itself over multiple molecules rather than being localised to a single one. This phenomenon, known as spatial coherence, allows a charge to travel very quickly over several nanometres and escape from its oppositely charged partner - an initial step which seems to be the key to generating long-lived charges, say the researchers. This can then be used to generate electricity or for chemical reactions.

By carefully engineering the way molecules pack together, the team found that it was possible to tune the spatial coherence and to amplify - or reduce - this long-range separation. "Perhaps most importantly the results suggest that because the process is so fast it is also energy efficient, which could result in more energy out of the solar cell," said Dr Akshay Rao, a co-author on the study from the Cavendish Laboratory.

Dr Alex Chin, who led the theoretical part of the project, added that, if you look beyond the implications of the study for organic solar cells, this is a clear demonstration of "how fundamental quantum-mechanical processes, such as coherence, play a crucial role in disordered organic and biological systems and can be harnessed in new quantum technologies".

探花直播work at Cambridge forms part of a broader initiative to harness high tech knowledge in the physics sciences to tackle global challenges such as climate change and renewable energy. This initiative is backed by both the UK Engineering and Physical Sciences Research Council (EPSRC) and the Cambridge Winton Programme for the Physics of Sustainability. 探花直播work at the 探花直播 of California in Santa Barbara was supported by the Center for Energy Efficient Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DC0001009.

Researchers have been able to tune 鈥榗oherence鈥� in organic nanostructures due to the surprise discovery of wavelike electrons in organic materials, revealing the key to generating 鈥渓ong-lived charges鈥� in organic solar cells - material that could revolutionise solar energy.

One does not expect to see such effects in organic molecules - which [...] tend to resemble a plate of cooked spaghetti

Simon G茅linas

Simon Gelinas

This is the experimental setup used to generate femtosecond laser pulses which serve as an ultrafast "flash " for the camera so that very rapid phenomenon can be filmed

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Rainforest remedy could spell end of dental pain

sjr81 — Wed, 14 Mar 2012 14:40:18 +0000

探花直播remedy, made from an Amazonian plant species from varieties of Acmella Oleracea and turned into a gel for medical use, has proved hugely successful during the first two phases of clinical trials and may hasten the end of current reliance on local anaesthetics in dental use and Non-Steroid Anti-Inflammatory Drugs (NSAIDs) in specific applications.

Cambridge 探花直播 anthropologist Dr Fran莽oise Barbira Freedman, the first westerner to be invited to live with the Keshwa Lamas in Amazonian Peru, is leading efforts to bring this wholly natural painkiller to the global marketplace as an organic alternative to synthetic painkillers.

In doing so, the company she founded, Ampika Ltd (a spin-out from Cambridge Enterprise, the 探花直播鈥檚 commercialisation arm) will be run according to strict ethical guidelines, and will be able to channel a percentage of any future profits back to the Keshwa Lamas community who agreed to share their expertise with her.

With no known side-effects during the past five years of Phase I and II trials, Dr Freedman, who has continued to visit and live among the Keshwa Lamas over the past 30 years, is confident the stringent Phase III trials (multi-location trials across a diverse population mix) will be the final hurdle to clear. If successful, Ampika鈥檚 plan is to bring the product to market in 2014/15.

She said: 鈥� 探花直播story began in 1975 when I first went to live among the indigenous people of Peru. We were trekking through the rainforest and I was having terrible trouble with my wisdom teeth. One of the men with me noticed and prepared a little wad of plants to bite onto. 探花直播pain went away. When it came back a few hours later, he had foreseen the need and kept plant material in his hunters鈥� bag for me.

鈥淚 forgot all about the wisdom teeth problem for many years until Cambridge-based neuroscientist Dr Mark Treherne asked me to bring some medicinal plant samples back in order to test them for neurological research. Almost as an afterthought I remembered to include the one I鈥檇 used on my teeth. It was added to the bottom of the list, but somehow the list got reversed and it was the first one tested back in the UK. It was immediately successful and we鈥檝e never looked back.

鈥淒uring the time I have spent with the Keshwa Lamas I鈥檝e learnt all about the different plants and leaves they use for everyday illnesses and ailments. I first went to Peru as a young researcher hoping to learn more about what was a secretive community who were experts in shamanism. Along the way I鈥檝e learnt a great deal about natural medicines and remedies; everything from toothache to childbirth.鈥�

鈥淭his treatment for toothache means we could be looking at the end of some injections in the dentist鈥檚 surgery. We鈥檝e had really clear result from the tests so far, particularly for peridodontological procedures such as root scaling and planing, and there are many other potential applications. 探花直播native forest people described to me exactly how the medicine could and should work and they were absolutely right. There are a range of mucous tissue applications it could benefit, and may even help bowel complaints such as IBS (irritable bowel syndrome).鈥�

探花直播Keshwa Lamas remedy represents the first clinical trial of a natural product in Peru using the International Convention of Clinical Trials, of which Peru is a signatory, the gold-standard for clinical trials that is recognised across the Pacific and Atlantic regions.

Dr Freedman, who will visit the Peruvian community again in the coming weeks, has already been able to channel some early funding to the Keshwa Lama to help in the creation of a medicinal plant garden to conserve plants and plant knowledge related to women鈥檚 health and maternity care 鈥� with the express aim of preserving wisdom for future generations.

She added: 鈥淲e think the remedy is better than current treatments because NSAID drugs are systemic and have long-term effects; the plant product is not systemic and does not have any known side-effects. We think people prefer to use natural products and this is particularly the case for baby teething 鈥� for which, to my knowledge, there is no clinically tested natural alternative.鈥�

探花直播dentists who carried out the Phase 2 trial reported a high level of satisfaction among their patients who disliked injections and did not need to use painkillers after the periodontological procedures.

There was also a higher rate of patient return for further appointments than average for the group with which the plant gel was used. 探花直播gel works by blocking nerve endings (sodium channel pathways).

Ampika has a portfolio of plant-based drug development, particularly related to women鈥檚 health conditions and Type 2 diabetes, which it hopes to develop in the coming years.

An ancient Incan toothache remedy 鈥� for centuries handed down among an indigenous people in the rainforests of Peru 鈥� could be on the cusp of revolutionising worldwide dental practice.

During the time I have spent with the Keshwa Lamas I鈥檝e learnt all about the different plants and leaves they use for everyday illnesses and ailments.

Dr Fran莽oise Barbira Freedman

探花直播plant used in the rainforest remedy

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