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Wearable solar panels with perovskite

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There was a bit of a flutter online in late July 2014 about solar cell research and perovskite, a material that could replace silicon therefore making solar cells more affordable, which hopefully would lead to greater adoption of the technology. Happily, the publishers of the study seem to have reissued their news release (h/t Aug. 11, 2014 news item on Nanwerk).

From the Wiley online press release Nr. 29/2014,

Textile solar cells are an ideal power source for small electronic devices incorporated into clothing. In the journal Angewandte Chemie, Chinese scientists have now introduced novel solar cells in the form of fibers that can be woven into a textile. The flexible, coaxial cells are based on a perovskite material and carbon nanotubes; they stand out due to their excellent energy conversion efficiency of 3.3 % and their low production cost.

The dilemma for solar cells: they are either inexpensive and inefficient, or they have a reasonable efficiency and are very expensive. One solution may come from solar cells made of perovskite materials, which are less expensive than silicon and do not require any expensive additives. Perovskites are materials with a special crystal structure that is like that of perovskite, a calcium titanate. These structures are often semiconductors and absorb light relatively efficiently. Most importantly, they can move electrons excited by light for long distances within the crystal lattice before they return to their energetic ground state and take up a solid position – a property that is very important in solar cells.

A team led by Hisheng Peng at Fudan University in Shanghai has now developed perovskite solar cells in the form of flexible fibers that can be woven into electronic textiles. Their production process is relatively simple and inexpensive because it uses a solution-based process to build up the layers.

The anode is a fine stainless steel wire coated with a compact n-semiconducting titanium dioxide layer. A layer of porous nanocrystalline titanium dioxide is deposited on top of this. This provides a large surface area for the subsequent deposition of the perovskite material CH3NH3PbI3. This is followed by a layer made of a special organic material. Finally a transparent layer of aligned carbon nanotubes is continuously wound over the whole thing to act as the cathode. The resulting fiber is so fine and flexible that it can be woven into textiles.

The perovskite layer absorbs light, that excites electrons and sets them free, causing a charge separation between the electrons and the formally positively charged “holes” The electrons enter the conducting band of the compact titanium dioxide layer and move to the anode. The “holes” are captured by the organic layer. The large surface area and the high electrical conductivity of the carbon nanotube cathode aid in the rapid conduction of the charges with high photoelectric currents. The fiber solar cell can attain an energy conversion efficiency of 3.3 %, exceeding that of all previous coaxial fiber solar cells made with either dyes or polymers.

Here’s an image used in the press release illustrating the new fiber,

[downloaded from http://www.wiley-vch.de/vch/journals/2002/press/201429press.pdf]

[downloaded from http://www.wiley-vch.de/vch/journals/2002/press/201429press.pdf]

Here’s a link to and a citation for the paper,

Integrating Perovskite Solar Cells into a Flexible Fiber by Longbin Qiu, Jue Deng, Xin Lu, Zhibin Yang, and Prof. Huisheng Peng. Angewandte Chemie International Edition DOI: 10.1002/anie.201404973 Article first published online: 22 JUL 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

I found a second item about perovskite and solar cells in a May 16, 2014 article by Vicki Marshall for Chemistry World which discussed some research in the UK (Note: Links have been removed),

A lead-free and non-toxic alternative to current perovskite solar-cell technology has been reported by researchers in the UK: tin halide perovskite solar cells. They are also cheaper to manufacture than the silicon solar cells currently dominating the market.

Nakita Noel, part of Henry Snaith’s research team at the University of Oxford, describes how perovskite materials have caused a bit of a whirlwind since they came out in 2009: ‘Everybody that’s working in the solar community is looking to beat silicon.’ Despite the high efficiency of conventional crystalline silicon solar cells (around 20%), high production and installation costs decrease their economic feasibility and widespread use.

The challenge to find a cheaper alternative led to the development of perovskite-based solar cells, as organic–inorganic metal trihalide perovskites have both abundant and cheap starting materials. However, the presence of lead in some semiconductors could create toxicology issues in the future. As Noel puts it ‘every conference you present at somebody is bound to put up their hand and ask “What about the lead – isn’t this toxic?”’

…

Brian Hardin, co-founder of PLANT PV, US, and an expert in new materials for photovoltaic cells, says the study ‘should be considered a seminal work on alternative perovskites and is extremely valuable to the field as they look to better understand how changes in chemistry affect solar cell performance and stability.’

Here’s a link to and a citation for the UK researchers’ paper,

Lead-free organic–inorganic tin halide perovskites for photovoltaic applications by Nakita K. Noel, Samuel D. Stranks, Antonio Abate, Christian Wehrenfennig, Simone Guarnera, Amir-Abbas Haghighirad, Aditya Sadhana, Giles E. Eperon, Sandeep K. Pathak, Michael B. Johnston, Annamaria Petrozza, Laura M. Herza, and Henry J. Snaith. Energy Environ. Sci., 2014, Advance Article DOI: 10.1039/C4EE01076K First published online 01 May 2014

This article was open access until June 27, 2014 but now it is behind a paywall.

I notice there’s no mention of lead in the materials describing the research paper from the Chinese scientists. Perhaps they were working with lead-free materials.

Tony Clement announces Canadian government nano investment in two Alberta firms

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Tony Clement, Canada’s Minister of Industry, announced investments totaling over $500,000 to two Alberta-based firms associated with nanotechnology. From the news release on Marketwire [ETA Aug.18.10: there’s also this link to the item on Nanowerk],

The Honourable Tony Clement, Minister of Industry, today announced contributions of $285,268 to Sonoro Energy Limited and $257,000 to IntelligentNano Incorporated from the National Research Council of Canada Industrial Research Assistance Program (NRC-IRAP). The funding supports innovative research and development projects that will assist both firms in developing high-tech solutions for global markets.

“Our government is investing in science and technology to create good jobs, strengthen the economy and improve the quality of life of Canadians,” said Minister Clement. “This government is supporting Canadian firms that successfully develop and apply innovative technologies. Canada’s Economic Action Plan is bolstering scientific research and commercialization, while creating good jobs and economic growth.”

Edmonton boasts Canada’s largest and most technologically advanced nanotechnology research infrastructure, centred around the National Institute of Nanotechnology (NINT). NINT is a joint initiative between the National Research Council of Canada, the University of Alberta, and the Government of Alberta.

So there you have it, the follow up to yesterday’s news flash. If you’re curious about the two companies, Sonoro is using the money to,

[support] a project that will seek to accelerate the commercial upgrading of heavy oil into synthetic crude, by small and medium- sized producers in remote areas. As the technology is both scalable and repeatable, Sonoro is actively pursuing heavy oil resource opportunities, particularly in remote global regions where there is heavy oil that could benefit from low-cost upgrading technology. Sonoro Energy has developed and patented a proprietary sonic reactor technology platform that transfers sonic energy on an industrial scale to physical, chemical or biological processes.

IntelligentNano will apply its funds towards,

further development of the “Sonacell,” a device for amplifying and accelerating the growth of therapeutic stem cells. Stem cells have an ability to self-renew and the potential to replace diseased and damaged tissues in the body, without the risk of rejection and side effects. Adults have a very small number of such cells; IntelligentNano has developed the “Sonacell,” which will make it possible to harvest and grow a sufficient quantity of a patient’s own stem cells for use in medical therapies. The “Sonacell” opens the door to the possibility of treatments for diseases like diabetes, arthritis, Parkinson’s and spinal cord injuries.

Textiles used as batteries at UC Berkeley; University of Calgary, quantum entanglement and building blocks; Raymor Industries has a nano problem with its shareholders?

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There seems to be a race to get our clothes electrified so we can become portable recharging devices. From the news item on Azonano,

In research that gives literal meaning to the term “power suit,” University of California, Berkeley, engineers have created energy-scavenging nanofibers that could one day be woven into clothing and textiles.

These nano-sized generators have “piezoelectric” properties that allow them to convert into electricity the energy created through mechanical stress, stretches and twists.

“This technology could eventually lead to wearable ‘smart clothes’ that can power hand-held electronics through ordinary body movements,” said Liwei Lin, UC Berkeley professor of mechanical engineering and head of the international research team that developed the fiber nanogenerators.

This announcement is on the heels of a similar announcement (noted in my posting of Jan.22.10 here)  from researchers at the University of Stanford in California.

Meanwhile, scientists at the University of Calgary are playing with construction toys (they use the lego metaphor, which seems quite popular right now). From the news release on the University of Calgary website (thanks to Azonano where I first found notice of the item),

While many of us enjoyed constructing little houses out of toy bricks, this task is much more difficult if the bricks are elementary particles. It is even harder if these are particles of light—photons—which can only exist while flying at an incredible speed and vanish if they touch anything.

Yet a team at the University of Calgary has accomplished exactly that. By manipulating a mysterious quantum property of light known as entanglement, they are able to mount up to two photons on top of one another to construct a variety of quantum states of light—that is, build two-story quantum toy houses of any style and architecture.

The research has just (yesterday, Feb.14.10) been published in Nature Photonics. You can read the abstract (here after you scroll down) but the rest of the article is behind a paywall.

I found something rather odd this morning about Raymor Industries. It’s a Canadian nanotechnology company (their products are based on single-walled carbon nanotubes) traded on the TSX that is currently experiencing difficulty with, at least some, shareholders. From the item on PRNewsWire,

RAYMOR INDUSTRIES INC. (TSX Venture RAR, RAYRF) is a leading Canadian developer of high technology and a producer of advanced materials and nanomaterials for high value-added applications. Raymor holds the exclusive rights to more than 20 patents throughout the world, with other patents pending. Shareholders have formed a group to fight to protect our shareholder rights and prevent the current board of directors from delisting and the eliminating the common shares of the corporation.  The group is called The Raymor Investors Special Action Group.  The group is sending out this communication to get the attention of the 8000 shareholders and advise them that an appeal to the recent January 27, 2010 court ruling has been launched and is underway.  A strong and reasonable chance exists that the appeal can be won.

If you’re curious about the company and its products, you can read more here at their website, although they offer no additional information about the contretemps.

Participatory science; wearable batteries; radio interview with Andrew Maynard; shadow science ministers in Canada’s political parties

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Ordinary people (nonscientists like me) have a long tradition of participating in scientific research in areas such as astronomy and ornithology (bird watching). A local example is the eagle count which takes place at Brackendale every year. (Aside: The 2010 count has already taken place but it’s still possible to attend festival events which are now part of the Brackendale eagle count experience.)

Someone whose science interests may be more esoteric can have trouble finding opportunities to pursue their interests. Thanks to the Science Cheerleader there is a new online resource to help you find a project. From the Science Cheerleader blog,

Hot diggity-DOG! After years in the making, my partner, Michael Gold, and I–with generous support from Science House–have officially unveiled the beta version (that means this is still a work-in-progress) of ScienceForCitizens.net . Science journalist, Carl Zimmer, who frequently writes for Discover and Time Magazine, said “It’s like Amazon.com for all sorts of possibilities for doing cool citizen science”. We’ll take that

And thanks to the Pasco Phronesis blog for the info. about the Science Cheerleader.

For an abrupt change of pace: Yes, you could be wearing your batteries at some point in the future. Scientists at Stanford University (CA) have found a way to easily and inexpensively turn cotton or polyester fibres into batteries or, as they call it, wearable energy textiles or e-textiles. From the news item on BBC News,

“Wearable electronics represent a developing new class of materials… which allow for many applications and designs previously impossible with traditional electronics technologies,” the authors [of the study published in ACS Nano Letters] wrote.

A number of research efforts in recent years have shown the possibility of electronics that can be built on flexible and even transparent surfaces – leading to the often-touted “roll-up display”.

However, the integration of electronics into textiles has presented different challenges, in particular developing approaches that work with ordinary fabrics.

Now, Yi Cui and his team at Stanford University in the US has shown that their “ink” made of carbon nanotubes – cylinders of carbon just billionths of a metre across – can serve as a dye that can simply and cheaply turn a t-shirt into an “e-shirt”.

I’ve taken a look at the research paper which, as these things go, is pretty readable. Bravo to the American Chemical Society (ACS) for not placing the material behind a paywall. The article, Stretchable, Porous and Conductive Energy Textiles,  published in the ACS journal Nano Letters is here.

I had the pleasure of listening to a radio interview on Whyy Radio conducted by Marty Moss-Coane where she interviewed Dr. Andrew Maynard, Chief Science Advisor for the Project on Emerging Nanotechnolgies. The interview (approximately 50 mins.)  titled, The Science and Safety of Nanotechnology, is available for listening here. Moss-Coane was well-prepared, asked good questions, and had listeners call in with their own questions. Dr. Andrew Maynard was, as always, very likable and interesting.

After my recent posting on science policy in Canada and the four major political parties, I thought I’d check out the various shadow science ministers or critics. Here’s what I found,

Gary Goodyear, Conservative, Minister of State (Science and Technology)

Jim Maloway, NDP, Science and Technology [portfolio]

Frances Coates, Green Party, shadow minister Science and Technology

Marc Garneau, Liberal Party, Industry, Science and Technology critic

I have looked at all their websites and Garneau seems the most interested in science and technology issues. Given that he’s a former astronaut and is an engineer, one might expect that he would have a major interest in the subject. He’s written a paper on the subject (thanks to the folks at The Black Hole for finding it). If you go here and either read or scroll to the bottom, you will find a link to his paper. He also has a poll on his website, What is the importance of science and technology to create the jobs for tomorrow? You can go here to answer the question. As for the others, Goodyear lists a series of announcements in news releases as accomplishments which makes identifying his actual accomplishments difficult. Jim Maloway does not mention science on his website and Frances Coates posted a few times on her blog in 2008 but made no mention of science.