solar cells made entirely of carbon--Printed Solar Panels, Lithium-Ion Power

Low-cost solar cell for everyday use

Typical solar cells use expensive rare earth minerals. Researchers at Stanford University have come up with an alternative method of creating solar cells made entirely of carbon

Mirror Bureau

Posted On Saturday, November 03, 2012 at 08:39:51 AM

Stanford University scientists have built the first solar cell made entirely of carbon, a promising alternative to the expensive materials used in photovoltaic devices today. The results are published in the journal ACS Nano.

“Carbon has the potential to deliver high performance at a low cost,” said study senior author Zhenan Bao. “To the best of our knowledge, this is the first demonstration of a working solar cell that has all of the components made of carbon.”

Unlike rigid silicon solar panels that adorn many rooftops, Stanford’s thin film prototype is made of carbon materials that can be coated from solution.

“Perhaps in the future we can look at alternative markets where flexible carbon solar cells are coated on the surface of buildings, on windows or on cars to generate electricity,” Bao said.

The coating technique also has the potential to reduce manufacturing costs, said student Michael Vosgueritchian, co-lead author of the study with Marc Ramuz. “Processing silicon-based solar cells requires a lot of steps,” Vosgueritchian explained.

“But our entire device can be built using simple coating methods that don’t require expensive tools and machines.”

Carbon nanomaterials

The Bao group’s experimental solar cell consists of a photoactive layer, which absorbs sunlight, sandwiched between two electrodes. In a typical thin film solar cell, the electrodes are made of conductive metals and indium tin oxide (ITO).

“Materials like indium are scarce and becoming more expensive as the demand for solar cells, touchscreen panels and other electronic devices grows,” Bao said. “Carbon, on the other hand, is low cost and Earth-abundant.”

For the study, Bao and her colleagues replaced the silver and ITO used in conventional electrodes with graphene – sheets of carbon that are one atom thick and single-walled carbon nanotubes that are 10,000 times narrower than a human hair.

“Carbon nanotubes have extraordinary electrical conductivity and light-absorption properties,” Bao said.

For the active layer, the scientists used material made of carbon nanotubes and “buckyballs” – soccer ball-shaped carbon molecules just one nanometer in diameter.

The research team recently filed a patent for the entire device. “Every component in our solar cell, from top to bottom, is made of carbon materials,” Vosgueritchian said. “Other groups have reported making all-carbon solar cells, but they were referring to just the active layer in the middle, not the electrodes.”

One drawback of the all-carbon prototype is that it primarily absorbs near-infrared wavelengths of light, contributing to a laboratory efficiency of less than 1 per cent – much lower than commercially available solar cells. “We clearly have a long way to go on efficiency,” Bao said.

“But with better materials and better processing techniques, we expect that the efficiency will go up quite dramatically.”

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A century ago, The University of Texas was built on energy. Some sources may have changed, but as these brilliant innovations prove, UT is still charging ahead.

1. Spray solar panels on.

The sun pours enough energy onto the Earth in an hour to supply all our energy needs in a year, if we could harvest it. Silicon-based solar cells are still pricey, largely because manufacturing them eats up a lot of energy. For energy users on a budget—and that would be most of us—the numbers still favor fossil fuels. But what will future solar panels, or photovoltaics, be like?
Think ink on a plastic sheet. Brian Korgel, professor of chemical engineering and a nanotechnology expert, is among a group of scientists who are reimagining photovoltaics. Steering away from silicon in favor of copper, indium, gallium, and selenium (a combo he calls CIGS), Korgel is using extremely small crystals of these elements to form a liquid that can collect solar energy. This “nanocrystal ink” can be used to make photovoltaics at far lower temperatures than silicon requires, and low temperatures in turn allow for more delicate and multilayered devices. Much like traditional ink, it can be printed or even sprayed onto flexible surfaces.
“We’re trying to create a process like a printing press for making solar cells,” Korgel says. “One thing that I think could be possible would be to have a solar panel that’s almost like a carpet you unfurl on the top of your roof.”
There are many alternatives to silicon, and lightweight CIGS-based photovoltaics aren’t new. But Korgel hopes that painting with nanocrystals will allow solar cells to be mass-produced quickly and cheaply while remaining efficient enough to compete with other energy sources.
How efficient do newfangled photovoltaics need to be? To succeed on the market, the magic number is 10 percent. A few years ago, Korgel’s group proved that CIGS inks could work at 1 percent efficiency; they have since pushed that to 3 percent with low-heat and 7 percent for high-heat manufacturing methods. (By comparison, silicon solar panels are about 15-20 percent efficient.) “There’s no reason to believe you couldn’t get to 10 percent,” Korgel says. “It’s just a challenge of figuring out how to do it.”
While Korgel says his group is one of many around the world working on more cost-effective solar cells, he’s optimistic that somebody will invent photovoltaics that hit “grid parity,” meeting or beating the cost of grid power, in the next decade. “The pace and progress in the area of photovoltaics has been really, really impressive in the last four or five years,” he says. “It’s the kind of problem that if you solved it would really change the world.” —Jenny Blair

2. Develop the next generation of lithium-ion batteries.

UT scientists have repeatedly pushed boundaries when it comes to batteries. In the 1970s, Cockrell School professor John Goodenough pioneered lithium-ion technology to power the vast array of small electronics we rely on today. Now his colleague Arumugam Manthiram, director of UT’s Texas Materials Institute and the Materials Science and Engineering Program, has taken Goodenough’s discoveries to the next level.
Manthiram is innovating how to use lithium-ion technology to power cars and store electricity produced by renewable sources. Cost, cycle life, safety, energy, and power are major barriers.
Manthiram is developing safe, nano-engineered alloy anodes to replace the unsafe graphite anodes now used, in addition to new high-energy cathode materials.
To bring these ideas to market, Manthiram partnered with Cleantech entrepreneur Bill Ott. They co-founded ActaCell, a company that got early support from the Austin Technology Incubator’s Clean Energy division and seed funding from the Texas Emerging Technology Fund.
ActaCell is now developing high-power lithium-ion batteries based on the technology developed in Manthiram’s lab. —Maria Arrellaga
Read the next great ideas on energy here.
Top, Illustration by Dan Page. Bottom, John Goodenough. Photo by Marc Brown.

A pathbreaking device that can prove to be a giant leap for cancer treatment

Published: Friday, Nov 2, 2012, 16:24 IST
Place: London | Agency: IANS

A pathbreaking device will do away with invasive tests and long waits at clinics in diagnosing all kinds of cancers. In a mere 20 minutes, the device could also tell specialists which drug to prescribe for the cancer.
The world's first tumour profiler is being developed by QuantuMDx, in the universities of Newcastle and Sheffield. It will be used by the National Health Service of the UK within three years.
Company representatives said the device can potentially prolong the lives of the 12 million newly diagnosed cancer victims worldwide.
It will help surgeons remove most, if not all of the tumour, and allow cancer specialists to prescribe the correct treatment.
The device is relying on advanced nanotechnology, analysing microscopic amounts of tissue to work out the type of cancer, its genetic make-up and how far it has developed, the Daily Mail reports.
Sir John Burn, professor at the Newcastle University and medical director of QuantuMDx, says: "We have a world leading position to deliver complex DNA tumour testing to the routine pathology lab or even to the operating theatre."
"A low-cost device requiring no technical expertise will extract, amplify and analyse tumour DNA to make sure the patient gets the right treatment first time and without delay," he adds.
QuantuMDx chief executive Elaine Warburton said: "Currently tumour samples are sent away to a centralised sequencing laboratory, which can take several weeks to turnaround results, usually at a very high price which is not routinely affordable to many economies."
"As far as we are aware, QuantuMDx's current underlying technologies, which can break up a sample and extract the DNA in under five minutes, represents a first in the world for complex molecular diagnostics," Warburton said.

Alzheimer's wonder pill that halts effect of disease, could be available in four years

New pill thought to be twice as effective as any other treatments on market
Research leader says it 'flatlines the disease' and can 'pull people back the brink'

By Fiona Macrae and Paul Bentley
PUBLISHED: 16:08 GMT, 30 October 2012 | UPDATED: 02:38 GMT, 31 October 2012

A pill said to halt the devastating onset of Alzheimer’s disease could be on the market within four years, scientists said yesterday.
Believed to be more than twice as good as anything already available, it could greatly slow or even halt the progression of the cruel illness.
Given early enough, it could stop Alzheimer’s from ever developing, an international dementia conference was told yesterday.

Later symptoms of dementia include confusion and mood swings. LMTX dissolves the 'tangles' of protein that are a hallmark of the dementia (file)

A version of the twice-a-day pill – developed by British scientists – has already been tested on patients, with ‘unprecedented’ results.
Its inventor, Professor Claude Wischik, of Aberdeen University, said: ‘It flatlines the disease. If you get in early, you can pull people back from the brink.’

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Eventually, the drug could be prescribed to everyone aged 60-plus to keep their mind sharp, even if they have yet to show signs of dementia.
However, others have urged caution, warning that even extremely promising drugs can fail in the final stages of testing.
Alzheimer’s and other forms of dementia affect more than 800,000 Britons, with the number expected to double in a generation as the population ages.
Existing drugs delay the progress of Alzheimer’s, but their failure to tackle the underlying cause in the brain means that the effect quickly wears off and the disease soon takes its devastating course.

Research leader Professor Claude Wischik: Says you can stop decline if you introduce drug early enough

The new drug, known only as LMTX, works in a different way to current treatments and to many of the Alzheimer’s tablets and jabs in development, which target the brain’s chemistry or the build-up of a brain-clogging protein called beta-amyloid.
LMTX, in contrast, dissolves the ‘tangles’ of protein that are a hallmark of the disease and spread through the brain like an infection, stopping them working from within.
An earlier version of LMTX, called Rember, has already been tested on patients with promising results.
Given to men and women with mild to moderate dementia, the Rember capsules slowed the progression of the disease by 90 per cent for two years.
This made it more than twice as good as current treatments.
Patients, and their loved ones, told how they were more confident and better able to cope with daily life.
One woman with mild Alzheimer’s was able to return to work and, around six years on, is still taking the drug and still working.
However, Rember had several digestive side-effects and there were problems taking it with food, leading to its reformulation as LMTX.
To prove that LMTX is just as effective but without as many complications, TauRx Therapeutics, the drug firm Professor Wischik co-founded, is starting two ‘final-hurdle’ trials that will involve almost 1,500 men and women with mild or moderate Alzheimer’s.
The patients, including some 150 Britons, will take the pill or a dummy drug for up to 18 months.
If LMTX is deemed safe and effective by the regulatory authorities, it could be on sale in just four years, the Clinical Trials Conference on Alzheimer’s Disease in Monte Carlo heard.
Several highly promising Alzheimer’s drugs have recently failed to make the grade but Professor Wischik is confident of success.
He said that even if LMTX simply slows the progression of the disease, rather than completely halting it, it could still be of huge benefit.
‘Even if people are progressing very slowly, they can stay at home with their loved ones for longer, rather than having to go into institutional care,’ he said.
‘But, hopefully, if you bring it in early enough, you can stop this or at least put a big dent in it.’
Dr Richard Perry, an Alzheimer’s expert at London’s Charing Cross Hospital and at the Re:Cognition Health memory clinic, said that the protein tangles are a ‘very legitimate target’.
He added that LMTX is one to watch but its value won’t be known until the large-scale trials are completed.
Rebecca Wood, of the Alzheimer’s Research UK charity, said: ‘With current Alzheimer’s drugs acting to relieve symptoms, there is a desperate need for new treatments which can slow or stop the disease.
‘Support for research must be maintained if we are to keep building on our knowledge and developing potential new ways to beats this devastating disease.’

'TREATMENT THAT GAVE MY WIFE HOPE'

Sandra Sutherland and her husband Ian say the drug slowed down Mrs Sutherland's Alzheimer's

For five years, Sandra Sutherland’s Alzheimer’s was kept at bay by the new drug’s predecessor Rember.
But since coming off Rember in August last year, because it did not mix well with another drug she had to start taking for epilepsy, the 65-year-old now struggles to concentrate for more than ten minutes at a time.
The ex-accounts worker’s husband Ian said: ‘When she was on Rember there was no notable deterioration.
Since she has come off I see distinct deterioration in her mental abilities.
‘She now takes [rival Alzheimer’s drug] Aricept.
'Her short-term memory is getting worse. She remembers names, but can’t remember what happened yesterday.
'Her mood swings are getting more pronounced. 'It’s more difficult now to communicate.’
Former power station worker Jimmy Hardie, 76, also started on a Rember trial in 2006, a year after being diagnosed with Alzheimer’s, and continues to take the drug.
'While he used to put sugar mistakenly in the fridge and suffered mood swings, Mr Hardie, of Boddam, Aberdeenshire, can now spend much of his day working on his tractors.
His wife Dorothy said she believes the treatment has helped him gain confidence, adding: ‘He’ll sit for several hours at a time and read the newspaper.
He’s very interested in current affairs and will watch Question Time and This Week every Thursday.’