Tag Archives: Ted Sargent

Bob McDonald: How is Canada on the ‘forefront of pushing nanotechnology forward’?

Mr. Quirks & Quarks, also known as the Canadian Broadcasting Corporation’s (CBC) Bob McDonald, host of the science radio programme Quirks & Quarks, published an Oct. 9, 2016 posting on the programme’s CBC blog about the recently awarded 2016 Nobel Prize for Chemistry and Canada’s efforts in the field of nanotechnology (Links have been removed),

The Nobel Prize in Chemistry awarded this week for developments in nanotechnology heralds a new era in science, akin to the discovery of electromagnetic induction 185 years ago. And like electricity, nanotechnology could influence the world in dramatic ways, not even imaginable today.

The world’s tiniest machines

The Nobel Laureates developed molecular machines, which are incredibly tiny devices assembled one molecule at a time, including a working motor, a lifting machine, a micro-muscle, and even a four wheel drive vehicle, all of which can only be seen with the most powerful electron microscopes. While these lab experiments are novel curiosities, the implications are huge, and Canada is on the forefront of pushing this research forward. [emphasis mine]

McDonald never explains how Canadians are pushing nanotechnology research further but there is this (Note: Links have been removed),

Many universities offer degree programs on the subject while organizations such as the National Institute for Nanotechnology at the University of Alberta, and the Waterloo Institute for Nanotechnology at the University of Waterloo in Ontario, are conducting fundamental research on these new novel materials.

Somehow he never mentions any boundary-pushing research. hmmm

To be blunt, it’s very hard to establish Canada’s position in the field since ‘nanotechnolgy research’ as such doesn’t exist here in the way it does in the United States, Korea, Iran, Germany, China, the United Kingdom, Ireland, Austria, and others. It’s not a federally coordinated effort in Canada despite the fact that we have a Canada National Research Council (NRC) National Institute of Nanotechnology (NINT) in Alberta. (There’s very little information about research on the NINT website.) A Government of Canada NanoPortal is poorly maintained and includes information that is seriously out-of-date. One area where Canadians have been influential has been at the international level where we’ve collaborated on a number of OECD (Organization for Economic and Cooperative Development) projects focused on safety (occupational and environmental, in particular) issues.

Canada’s Ingenuity Lab, a nanotechnology project that appeared promising, hasn’t made many research announcements and seems to be a provincial (Alberta) initiative rather than a federal one. In fact, the most activity in the field of nanotechnology research has been at the provincial level with Alberta and Québec in the lead, if financial investment is your primary measure, and Ontario following, then the other provinces trailing from behind. Unfortunately, I’ve never come across any nanotechnology research from the Yukon or other parts North.

With regard to research announcements, the situation changes and you have Québec and Ontario assuming the lead positions with Alberta following. As McDonald noted, the University of Waterloo has a major nanotechnology education programme and the University of Toronto seems to have a very active research focus in that field (Ted Sargent and solar cells and quantum dots) and the University of Guelph is known for its work in agriculture and nanotechnolgy (search this blog using any of the three universities as a search term). In Québec, they’ve made a number of announcements about cutting edge research. You can search this blog for the names Sylvain Martel, Federico Rosei, and Claude Ostiguy (who seems to work primarily in French), amongst others. CelluForce, based in Quebec, and once  a leader (not sure about the situation these days) in the production of cellulose nanocrystals (CNC). One side comment, CNC was first developed at the University of British Columbia, however, Québec showed more support (provincial funding) and interest and the bulk of that research effort moved.

There’s one more shout out and that’s for Blue Goose Biorefineries in the province of Saskatchewan, which sells CNC and offers services to help companies  research applications for the material.

One other significant area of interest comes to mind, the graphite mines in Québec and Ontario which supply graphite flakes used to produce graphene, a material that is supposed to revolutionize electronics, in particular.

There are other research efforts and laboratories in Canada but these are the institutions and researchers with which I’m most familiar after more than eight years of blogging about Canadian nanotechnology. That said, if I’ve missed any significant, please do let me know in the comments section of this blog.

Split some water molecules and save solar and wind (energy) for a future day

Professor Ted Sargent’s research team at the University of Toronto has a developed a new technique for saving the energy harvested by sun and wind farms according to a March 28, 2016 news item on Nanotechnology Now,

We can’t control when the wind blows and when the sun shines, so finding efficient ways to store energy from alternative sources remains an urgent research problem. Now, a group of researchers led by Professor Ted Sargent at the University of Toronto’s Faculty of Applied Science & Engineering may have a solution inspired by nature.

The team has designed the most efficient catalyst for storing energy in chemical form, by splitting water into hydrogen and oxygen, just like plants do during photosynthesis. Oxygen is released harmlessly into the atmosphere, and hydrogen, as H2, can be converted back into energy using hydrogen fuel cells.

Discovering a better way of storing energy from solar and wind farms is “one of the grand challenges in this field,” Ted Sargent says (photo above by Megan Rosenbloom via flickr) Courtesy: University of Toronto

Discovering a better way of storing energy from solar and wind farms is “one of the grand challenges in this field,” Ted Sargent says (photo above by Megan Rosenbloom via flickr) Courtesy: University of Toronto

A March 24, 2016 University of Toronto news release by Marit Mitchell, which originated the news item, expands on the theme,

“Today on a solar farm or a wind farm, storage is typically provided with batteries. But batteries are expensive, and can typically only store a fixed amount of energy,” says Sargent. “That’s why discovering a more efficient and highly scalable means of storing energy generated by renewables is one of the grand challenges in this field.”

You may have seen the popular high-school science demonstration where the teacher splits water into its component elements, hydrogen and oxygen, by running electricity through it. Today this requires so much electrical input that it’s impractical to store energy this way — too great proportion of the energy generated is lost in the process of storing it.

This new catalyst facilitates the oxygen-evolution portion of the chemical reaction, making the conversion from H2O into O2 and H2 more energy-efficient than ever before. The intrinsic efficiency of the new catalyst material is over three times more efficient than the best state-of-the-art catalyst.

Details are offered in the news release,

The new catalyst is made of abundant and low-cost metals tungsten, iron and cobalt, which are much less expensive than state-of-the-art catalysts based on precious metals. It showed no signs of degradation over more than 500 hours of continuous activity, unlike other efficient but short-lived catalysts. …

“With the aid of theoretical predictions, we became convinced that including tungsten could lead to a better oxygen-evolving catalyst. Unfortunately, prior work did not show how to mix tungsten homogeneously with the active metals such as iron and cobalt,” says one of the study’s lead authors, Dr. Bo Zhang … .

“We invented a new way to distribute the catalyst homogenously in a gel, and as a result built a device that works incredibly efficiently and robustly.”

This research united engineers, chemists, materials scientists, mathematicians, physicists, and computer scientists across three countries. A chief partner in this joint theoretical-experimental studies was a leading team of theorists at Stanford University and SLAC National Accelerator Laboratory under the leadership of Dr. Aleksandra Vojvodic. The international collaboration included researchers at East China University of Science & Technology, Tianjin University, Brookhaven National Laboratory, Canadian Light Source and the Beijing Synchrotron Radiation Facility.

“The team developed a new materials synthesis strategy to mix multiple metals homogeneously — thereby overcoming the propensity of multi-metal mixtures to separate into distinct phases,” said Jeffrey C. Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems at Massachusetts Institute of Technology. “This work impressively highlights the power of tightly coupled computational materials science with advanced experimental techniques, and sets a high bar for such a combined approach. It opens new avenues to speed progress in efficient materials for energy conversion and storage.”

“This work demonstrates the utility of using theory to guide the development of improved water-oxidation catalysts for further advances in the field of solar fuels,” said Gary Brudvig, a professor in the Department of Chemistry at Yale University and director of the Yale Energy Sciences Institute.

“The intensive research by the Sargent group in the University of Toronto led to the discovery of oxy-hydroxide materials that exhibit electrochemically induced oxygen evolution at the lowest overpotential and show no degradation,” said University Professor Gabor A. Somorjai of the University of California, Berkeley, a leader in this field. “The authors should be complimented on the combined experimental and theoretical studies that led to this very important finding.”

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

Homogeneously dispersed, multimetal oxygen-evolving catalysts by Bo Zhang, Xueli Zheng, Oleksandr Voznyy, Riccardo Comin, Michal Bajdich, Max García-Melchor, Lili Han, Jixian Xu, Min Liu, Lirong Zheng, F. Pelayo García de Arquer, Cao Thang Dinh, Fengjia Fan, Mingjian Yuan, Emre Yassitepe, Ning Chen, Tom Regier, Pengfei Liu, Yuhang Li, Phil De Luna, Alyf Janmohamed, Huolin L. Xin, Huagui Yang, Aleksandra Vojvodic, Edward H. Sargent. Science  24 Mar 2016: DOI: 10.1126/science.aaf1525

This paper is behind a paywall.

University of New Brunswick (Canada), ‘sun in a can’, and buckyballs

Cutting the cost for making solar cells could be a step in the right direction for more widespread adoption. At any rate, that seems to be the motivation for Dr. Felipe Chibante of the University of New Brunswick  and his team as they’ve worked for the past three years or so on cutting production costs for fullerenes (also known as, buckminsterfullerenes, C60, and buckyballs). From a Dec. 23, 2015 article by Michael Tutton for Canadian Press,

A heating system so powerful it gave its creator a sunburn from three metres away is being developed by a New Brunswick engineering professor as a method to sharply reduce the costs of making the carbon used in some solar cells.

Felipe Chibante says his “sun in a can” method of warming carbon at more than 5,000 degrees Celsius helps create the stable carbon 60 needed in more flexible forms of photovoltaic panels.

Tutton includes some technical explanations in his article,

Chibante and senior students at the University of New Brunswick created the system to heat baseball-sized lumps of plasma — a form of matter composed of positively charged gas particles and free-floating negatively charged electrons — at his home and later in a campus lab.

According to a May 22, 2012 University of New Brunswick news release received funding of almost $1.5M from the Atlantic Canada Opportunities Agency for his work with fullerenes,

Dr. Felipe Chibante, associate professor in UNB’s department of chemical engineering, and his team at the Applied Nanotechnology Lab received nearly $1.5 million to lower the cost of fullerenes, which is the molecular form of pure carbon and is a critical ingredient for the plastic solar cell market.

Dr. Chibante and the collaborators on the project have developed fundamental synthesis methods that will be integrated in a unique plasma reactor to result in a price reduction of 50-75 per cent.

Dr. Chibante and his work were also featured in a June 10, 2013 news item on CBC (Canadian Broadcasting Corporation) news online,

Judges with the New Brunswick Innovation Fund like the idea and recently awarded Chibante $460,000 to continue his research at the university’s Fredericton campus.

Chibante has a long history of working with fullerenes — carbon molecules that can store the sun’s energy. He was part of the research team that discovered fullerenes in 1985 [the three main researchers at Rice University, Texas, received Nobel Prizes for the work].

He says they can be added to liquid, spread over plastic and shingles and marketed as a cheaper way to convert sunlight into electricity.

“What we’re trying to do in New Brunswick with the science research and innovation is we’re really trying to get the maximum bang for the buck,” said Chibante.

As it stands, fullerenes cost about $15,000 per kilogram. Chibante hopes to lower the cost by a factor of 10.

The foundation investment brings Chibante’s research funding to about $6.2 million.

Not everyone is entirely sold on this approach to encouraging solar energy adoption (from the CBC news item),

The owner of Urban Pioneer, a Fredericton [New Brunswick] company that sells alternative energy products, likes the concept, but doubts there’s much of a market in New Brunswick.

“We have conventional solar panels right now and they’re not that popular,” said Tony Craft.

“So I can’t imagine, like, when you throw something completely brand new into it, I don’t know how people are going to respond to that even, so it may be a very tough sell,” he said.

Getting back to Chibante’s breakthrough (from Tutton’s Dec. 23, 2015 article),

The 52-year-old researcher says he first set up the system to operate in his garage.

He installed optical filters to watch the melting process but said the light from the plasma was so intense that he later noticed a sunburn on his neck.

The plasma is placed inside a container that can contain and cool the extremely hot material without exposing it to the air.

The conversion technology has the advantage of not using solvents and doesn’t produce the carbon dioxide that other baking systems use, says Chibante.

He says the next stage is finding commercial partners who can help his team further develop the system, which was originally designed and patented by French researcher Laurent Fulcheri.

Chibante said he doesn’t believe the carbon-based, thin-film solar cells will displace the silicon-based cells because they capture less energy.

But he nonetheless sees a future for the more flexible sheets of solar cells.

“You can make fibres, you can make photovoltaic threads and you get into wearable, portable forms of power that makes it more ubiquitous rather than having to carry a big, rigid structure,” he said.

The researcher says the agreement earlier this month [Nov. 30 – Dec. 12, 2015] in Paris among 200 countries to begin reducing the use of fossil fuels and slow global warming may help his work.

By the way,  Chibante estimates production costs for fullerenes, when using his system, would be less that $50/kilogram for what is now the highest priced component of carbon-based solar cells.

There is another researcher in Canada who works in the field of solar energy, Dr. Ted Sargent at the University of Toronto (Ontario). He largely focuses on harvesting solar energy by using quantum dots. I last featured Sargent’s quantum dot work in a Dec. 9, 2014 posting.

Kavli Foundation roundtable on artificial synthesis as a means to produce clean fuel

A Sept. 9, 2015 news item on Azonano features a recent roundtable discussion about artificial photosynthesis and clean fuel held by the Kavli Foundation,

Imagine creating artificial plants that make gasoline and natural gas using only sunlight. And imagine using those fuels to heat our homes or run our cars without adding any greenhouse gases to the atmosphere. By combining nanoscience and biology, researchers led by scientists at University of California, Berkeley, have taken a big step in that direction.

Peidong Yang, a professor of chemistry at Berkeley and co-director of the school’s Kavli Energy NanoSciences Institute, leads a team that has created an artificial leaf that produces methane, the primary component of natural gas, using a combination of semiconducting nanowires and bacteria. The research, detailed in the online edition of Proceedings of the National Academy of Sciences in August, builds on a similar hybrid system, also recently devised by Yang and his colleagues, that yielded butanol, a component in gasoline, and a variety of biochemical building blocks.

The research is a major advance toward synthetic photosynthesis, a type of solar power based on the ability of plants to transform sunlight, carbon dioxide and water into sugars. Instead of sugars, however, synthetic photosynthesis seeks to produce liquid fuels that can be stored for months or years and distributed through existing energy infrastructure.

In a [Kavli Foundation] roundtable discussion on his recent breakthroughs and the future of synthetic photosynthesis, Yang said his hybrid inorganic/biological systems give researchers new tools to study photosynthesis — and learn its secrets.

There is a list of the participants and an edited transcript of the roundtable, which took place sometime during summer 2015, on the Kavli Foundation’s Fueling up: How nanoscience is creating a new type of solar power webpage (Note: Links have been removed),

The participants were:

PEIDONG YANG – is professor of chemistry and Chan Distinguished Professor of Energy at University of California, Berkeley, and co-director of the Kavli Energy NanoScience Institute at Berkeley National Laboratory and UC Berkeley. He serves as director of the California Research Alliance by BASF, and was a founding member of the U.S. Department of Energy (DOE) Joint Center for Artificial Photosynthesis (JCAP).
THOMAS MOORE – is Regents’ Professor of Chemistry and Biochemistry and past director of the Center for Bioenergy & Photosynthesis at Arizona State University. He is a past president of the American Society for Photobiology, and a team leader at the Center for Bio-Inspired Solar Fuel Production.
TED SARGENT – is a University Professor of Electrical and Computer Engineering at the University of Toronto where he is vice-dean for research for the Faculty of Applied Science and Engineering. He holds the Canada Research Chair in Nanotechnology and is a founder of two companies, InVisage Technologies and Xagenic.

THE KAVLI FOUNDATION (TKF): Solar cells do a good job of converting sunlight into electricity. Converting light into fuel seems far more complicated. Why go through the bother?

THOMAS MOORE: That’s a good question. In order to create sustainable, solar-driven societies, we need a way to store solar energy. With solar cells, we can make electricity efficiently, but we cannot conveniently store that electricity to use when it is cloudy or at night. If we want to stockpile large quantities of energy, we have to store it as chemical energy, the way it is locked up in coal, oil, natural gas, hydrogen and biomass.

PEIDONG YANG: I agree. Perhaps, one day, researchers will come up with an effective battery to store photoelectric energy produced by solar cells. But photosynthesis can solve the energy conversion and storage problem in one step. It converts and stores solar energy in the chemical bonds of organic molecules.

TED SARGENT: Much of the globe’s power infrastructure, from automobiles, trucks and planes to gas-fired electrical generators, is built upon carbon-based fossil fuels. So creating a new technology that can generate liquid fuels that can use this infrastructure is a very powerful competitive advantage for a renewable energy technology.

For someone who’s interested in solar energy and fuel issues, this discussion provide a good introduction to some of what’s driving the research and, happily, none of these scientists are proselytizing.

One final comment. Ted Sargent has been mentioned here several times in connection with his work on solar cells and/or quantum dots.

University of Toronto researchers combine 2 different materials for new hyper-efficient, light-emitting, hybrid crystal

The Sargent Group at the University of Toronto has been quite active with regard to LEDs (light-emitting diodes) and with quantum dots. Their latest work is announced in a July 16, 2015 news item on Nanotechnology Now (Note: I had to include the ‘oatmeal cookie and chocolate chips’ analogy in the first paragraph as it’s referred to subsequently),

It’s snack time: you have a plain oatmeal cookie, and a pile of chocolate chips. Both are delicious on their own, but if you can find a way to combine them smoothly, you get the best of both worlds.

Researchers in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering [University of Toronto] used this insight to invent something totally new: they’ve combined two promising solar cell materials together for the first time, creating a new platform for LED technology.

The team designed a way to embed strongly luminescent nanoparticles called colloidal quantum dots (the chocolate chips) into perovskite (the oatmeal cookie). Perovskites are a family of materials that can be easily manufactured from solution, and that allow electrons to move swiftly through them with minimal loss or capture by defects.

A July 15, 2015 University of Toronto news release (also on EurekAlert), which originated the news item, reveals more about the research (Note: A link has been removed),

“It’s a pretty novel idea to blend together these two optoelectronic materials, both of which are gaining a lot of traction,” says Xiwen Gong, one of the study’s lead authors and a PhD candidate working with Professor Ted Sargent. “We wanted to take advantage of the benefits of both by combining them seamlessly in a solid-state matrix.”

The result is a black crystal that relies on the perovskite matrix to ‘funnel’ electrons into the quantum dots, which are extremely efficient at converting electricity to light. Hyper-efficient LED technologies could enable applications from the visible-light LED bulbs in every home, to new displays, to gesture recognition using near-infrared wavelengths.

“When you try to jam two different crystals together, they often form separate phases without blending smoothly into each other,” says Dr. Riccardo Comin, a post-doctoral fellow in the Sargent Group. “We had to design a new strategy to convince these two components to forget about their differences and to rather intermix into forming a unique crystalline entity.”

The main challenge was making the orientation of the two crystal structures line up, called heteroexpitaxy. To achieve heteroepitaxy, Gong, Comin and their team engineered a way to connect the atomic ‘ends’ of the two crystalline structures so that they aligned smoothly, without defects forming at the seams. “We started by building a nano-scale scaffolding ‘shell’ around the quantum dots in solution, then grew the perovskite crystal around that shell so the two faces aligned,” explained coauthor Dr. Zhijun Ning, who contributed to the work while a post-doctoral fellow at UofT and is now a faculty member at ShanghaiTech.

The resulting heterogeneous material is the basis for a new family of highly energy-efficient near-infrared LEDs. Infrared LEDs can be harnessed for improved night-vision technology, to better biomedical imaging, to high-speed telecommunications.

Combining the two materials in this way also solves the problem of self-absorption, which occurs when a substance partly re-absorbs the same spectrum of energy that it emits, with a net efficiency loss. “These dots in perovskite don’t suffer reabsorption, because the emission of the dots doesn’t overlap with the absorption spectrum of the perovskite,” explains Comin.

Gong, Comin and the team deliberately designed their material to be compatible with solution-processing, so it could be readily integrated with the most inexpensive and commercially practical ways of manufacturing solar film and devices. Their next step is to build and test the hardware to capitalize on the concept they have proven with this work.

“We’re going to build the LED device and try to beat the record power efficiency reported in the literature,” says Gong.

I see that Sargent’s work is still associated with and supported by Saudi Arabia, from the news release,

This work was supported by the Ontario Research Fund Research Excellence Program, the Natural Sciences and Engineering Research Council of Canada (NSERC), and the King Abdullah University of Science & Technology (KAUST).

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

Quantum-dot-in-perovskite solids by Zhijun Ning, Xiwen Gong, Riccardo Comin, Grant Walters, Fengjia Fan, Oleksandr Voznyy, Emre Yassitepe, Andrei Buin, Sjoerd Hoogland, & Edward H. Sargent. Nature 523, 324–328 (16 July 2015) doi:10.1038/nature14563 Published online 15 July 2015

This paper is behind a paywall.

Finally, the researchers have made a .gif of their hybrid crystal available.

A glowing quantum dot seamlessly integrated into a perovskite crystal matrix (Image: Ella Marushchenko). Courtesy: University of Toronto

A glowing quantum dot seamlessly integrated into a perovskite crystal matrix (Image: Ella Marushchenko). Courtesy: University of Toronto

ETA July 17, 2015:

Dexter Johnson provides some additional insight into the work in his July 16, 2015 posting on the Nanoclast blog (on the Institute for Electrical and Electronics Engineers website), Note:  Links have been removed,

Ted Sargent at the University of Toronto has built a reputation over the years as being a prominent advocate for the use of quantum dots in photovoltaics. Sargent has even penned a piece for IEEE Spectrum covering the topic, and this blog has covered his record breaking efforts at boosting the conversion efficiency of quantum dot-based photovoltaics a few times.

Earlier this year, however, Sargent started to take an interest in the hot material that has the photovoltaics community buzzing: perovskite. …

Spray-on solar cells from the University of Toronto (Canada)

It’s been a while since there’s been a solar cell story from the University of Toronto (U of T) and I was starting to wonder if Ted (Edward) Sargent had moved to another educational institution. The drought has ended with the announcement of three research papers being published by researchers from Sargent’s U of T laboratory. From a Dec. 5, 2014 ScienceDaily news item,

Pretty soon, powering your tablet could be as simple as wrapping it in cling wrap.

That’s Illan Kramer’s … hope. Kramer and colleagues have just invented a new way to spray solar cells onto flexible surfaces using miniscule light-sensitive materials known as colloidal quantum dots (CQDs) — a major step toward making spray-on solar cells easy and cheap to manufacture.

A Dec. 4, 2014 University of Toronto news release (also on EurekAlert) by Marit Mitchell, which originated the news item, gives a bit more detail about the technology (Note: Links have been removed),

 Solar-sensitive CQDs printed onto a flexible film could be used to coat all kinds of weirdly-shaped surfaces, from patio furniture to an airplane’s wing. A surface the size of a car roof wrapped with CQD-coated film would produce enough energy to power three 100-watt light bulbs – or 24 compact fluorescents.

He calls his system sprayLD, a play on the manufacturing process called ALD, short for atomic layer deposition, in which materials are laid down on a surface one atom-thickness at a time.

Until now, it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing – an inefficient, slow and expensive assembly-line approach to chemical coating. SprayLD blasts a liquid containing CQDs directly onto flexible surfaces, such as film or plastic, like printing a newspaper by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler. In two recent papers in the journals Advanced Materials and Applied Physics Letters, Kramer showed that the sprayLD method can be used on flexible materials without any major loss in solar-cell efficiency.

Kramer built his sprayLD device using parts that are readily available and rather affordable – he sourced a spray nozzle used in steel mills to cool steel with a fine mist of water, and a few regular air brushes from an art store.

“This is something you can build in a Junkyard Wars fashion, which is basically how we did it,” says Kramer. “We think of this as a no-compromise solution for shifting from batch processing to roll-to-roll.”

“As quantum dot solar technology advances rapidly in performance, it’s important to determine how to scale them and make this new class of solar technologies manufacturable,” said Professor Ted Sargent, vice-dean, research in the Faculty of Applied Science & Engineering at University of Toronto and Kramer’s supervisor. “We were thrilled when this attractively-manufacturable spray-coating process also led to superior performance devices showing improved control and purity.”

In a third paper in the journal ACS Nano, Kramer and his colleagues used IBM’s BlueGeneQ supercomputer to model how and why the sprayed CQDs perform just as well as – and in some cases better than – their batch-processed counterparts. This work was supported by the IBM Canada Research and Development Centre, and by King Abdullah University of Science and Technology.

For those who would like to see the sprayLD device,

Here are links and citation for all three papers,

Efficient Spray-Coated Colloidal Quantum Dot Solar Cells by Illan J. Kramer, James C. Minor, Gabriel Moreno-Bautista, Lisa Rollny, Pongsakorn Kanjanaboos, Damir Kopilovic, Susanna M. Thon, Graham H. Carey, Kang Wei Chou, David Zhitomirsky, Aram Amassian, and Edward H. Sargent. Advanced Materials DOI: 10.1002/adma.201403281 Article first published online: 10 NOV 2014

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

Colloidal quantum dot solar cells on curved and flexible substrates by Illan J. Kramer, Gabriel Moreno-Bautista, James C. Minor, Damir Kopilovic, and Edward H. Sargent. Appl. Phys. Lett. 105, 163902 (2014); http://dx.doi.org/10.1063/1.4898635 Published online 21 October 2014

© 2014 AIP Publishing LLC

Electronically Active Impurities in Colloidal Quantum Dot Solids by Graham H. Carey, Illan J. Kramer, Pongsakorn Kanjanaboos, Gabriel Moreno-Bautista, Oleksandr Voznyy, Lisa Rollny, Joel A. Tang, Sjoerd Hoogland, and Edward H. Sargent. ACS Nano, 2014, 8 (11), pp 11763–11769 DOI: 10.1021/nn505343e Publication Date (Web): November 6, 2014

Copyright © 2014 American Chemical Society

All three papers are behind paywalls.

Given the publication dates for the papers, this looks like an attempt to get some previously announced research noticed by sending out a summary news release using a new ‘hook’ to get attention. I hope it works for them as it must be disheartening to have your research sink into obscurity because the announcements were issued during one or more busy news cycles.

One final note, if I understand the news release correctly, this work is still largely theoretical as there don’t seem to have been any field tests.

University of Toronto’s Ted Sargent and his colloidal quantum dots make news again

Ted Sargent at the University of Toronto is one of the most consistent communicators, in Canada, about nanoscale research. His work is focused on solar panels/cells and colloidal quantum dots and according to a Mar. 7, 2013 news release on EurekAlert, there have been some new developments,

A new technique developed by U of T Engineering Professor Ted Sargent and his research group could lead to significantly more efficient solar cells, according to a recent paper published in the journal Nano Letters.

The paper, “Jointly-tuned plasmonic-excitonic photovoltaics using nanoshells,” describes a new technique to improve efficiency in colloidal quantum dot photovoltaics, a technology which already promises inexpensive, more efficient solar cell technology. Quantum dot photovoltaics offers the potential for low-cost, large-area solar power – however these devices are not yet highly efficient in the infrared portion of the sun’s spectrum, which is responsible for half of the sun’s power that reaches the Earth.

The solution? Spectrally tuned, solution-processed plasmonic nanoparticles. These particles, the researchers say, provide unprecedented control over light’s propagation and absorption.

The new technique developed by Sargent’s group shows a possible 35 per cent increase in the technology’s efficiency in the near-infrared spectral region, says co-author Dr. Susanna Thon. Overall, this could translate to an 11 per cent solar power conversion efficiency increase, she says, making quantum dot photovoltaics even more attractive as an alternative to current solar cell technologies.

The University of Toronto Mar. 7, 2013 news release written by Terry Lavender, which is the original of the one on EurekAlert, goes on to explain the interest in colloidal quantum dots and to describe the new technique,

“There are two advantages to colloidal quantum dots,” Thon says. “First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum.

“Changing the size is very easy, and this size-tunability is a property shared by plasmonic materials: by changing the size of the plasmonic particles, we were able to overlap the absorption and scattering spectra of these two key classes of nanomaterials.”

Sargent’s group achieved the increased efficiency by embedding gold nanoshells directly into the quantum dot absorber film. Gold is not usually thought of as an economical material but researchers say lower-cost metals can be used to implement the same concept proved by Thon and her co-workers.

It’s exciting work and a 35% increase in efficiency sounds great, although the base efficiency isn’t mentioned. If your base is one and you increase it to two, you have a 100% increase. As I noted in my July 30, 2012 posting about the team’s last breakthrough which showed a 37% increase in efficiency for their technique but actually worked out to a 7% increase for solar cell efficiency,

I think the excitement over 7% indicates just how much hard work the researchers have accomplished to achieve this efficiency. It reminds me of reading about the early development of electricity (Power struggles; Scientific authority and the creation of practical electricity before Edison by Michael Brian Schiffer)  where accomplishments we would now consider minuscule built careers.

These increases  may be small but they are important not only for the development of solar cells but also as an illustration of how scientific breakthroughs are often a series of small steps and of the infinite patience exercised by researchers.

Colloidal quantum dot film from the University of Toronto and KAUST certified world’s most efficient

In my Sept. 20, 2011 posting, I featured an item about Ted Sargent ‘s (University of Toronto, Canada) work on colloidal quantum dot films. These films have now been certified as the world’s most efficient. There seems to be a lot of excitement given that these films have achieved a 7% efficiency rating. From the July 30, 2012 news item by Will Soutter on Azonano,

A team of scientists from the King Abdullah University of Science & Technology (KAUST) and University of Toronto (U of T) headed by Ted Sargent, an U of T Engineering Professor, has achieved a significant progress in the advancement of colloidal quantum dot (CQD) films, which in turn results in a CQD solar cell with an unprecedented efficiency of 7%.

The July 30, 2012 news release from the University of Toronto provides more detail,

“Previously, quantum dot solar cells have been limited by the large internal surface areas of the nanoparticles in the film, which made extracting electricity difficult,” said Dr. Susanna Thon, a lead co-author of the paper. “Our breakthrough was to use a combination of organic and inorganic chemistry to completely cover all of the exposed surfaces.”

The U of T cell represents a 37% increase in efficiency over the previous certified record. In order to improve efficiency, the researchers needed a way to both reduce the number of “traps” for electrons associated with poor surface quality while simultaneously ensuring their films were very dense to absorb as much light as possible. The solution was a so-called “hybrid passivation” scheme.

“By introducing small chlorine atoms immediately after synthesizing the dots, we’re able to patch the previously unreachable nooks and crannies that lead to electron traps,” explained doctoral student and lead co-author Alex Ip. “We follow that by using short organic linkers to bind quantum dots in the film closer together.”

Work led by Professor Aram Amassian of KAUST showed that the organic ligand exchange was necessary to achieve the densest film.

“The KAUST group used state-of-the-art synchrotron methods with sub-nanometer resolution to discern the structure of the films and prove that the hybrid passivation method led to the densest films with the closest-packed nanoparticles,” stated Professor Amassian.

I think the excitement over 7% indicates just how much hard work the researchers have accomplished to achieve this efficiency. It reminds me of reading about the early development of electricity (Power struggles; Scientific authority and the creation of practical electricity before Edison by Michael Brian Schiffer)  where accomplishments we would now consider minuscule built careers.

Ted Sargent and Inerjys

Ted Sargent, Canada Research Chair in Nanotechnology, University of Toronto, has been mentioned here a number of times regarding his work on solar cells. Here are a few of the mostly recent postings (not a complete list), June 28, 2011, July 11, 2011, and Sept. 20, 2011.

Now, a Montréal-based company, Inerjys Ventures has just announced that Ted Sargent has joined their board of advisors. From the Jan. 9, 2012 news item on MarketWatch,

Inerjys Ventures, a $1 billion renewable energy strategic investment fund and global leader in green finance, announced today that it has constituted a board of advisors and named its first members. Inerjys has brought together thought leaders from renewable energy, finance and government to guide its decisions and strategic vision as the world approaches a clean energy economy.

The announcement comes at a decisive time for Inerjys, which was recently featured at the prestigious World Climate Summit in Durban, South Africa. The firm is currently developing several large-scale renewable energy projects worldwide, to be announced as it completes the closing of its renewable energy investment fund, Inerjys Ventures. At a projected capitalization of $1 billion CAD, Inerjys Ventures will be the largest cleantech venture vehicle in Canada and one of the largest in the world. The board will convene regularly to direct the growth of Inerjys and will lend their expertise to analyze investment opportunities in Canada and around the world.

You can learn more about Inerjys here.

Nature of Things’ series: The Nano Revolution (Episode 3); Will Nano Save the Planet?

I’m never thrilled with titles of this ilk, Will Nano Save the Planet? Refreshingly, this episode featured some work being done by Canadian scientists (two of them) although the average Canadian could be forgiven for thinking that it’s the only nanotechnology research taking place in Canada.

It’s a little puzzling that they chose this final episode for a description of the term nanoscale. David Suzuki, the host, mentioned the ridges of skin on your fingers and noted that a nanoparticle is 80,000 times smaller than the distance between the ridges. (If you want a really good description of scale, I recommend listening to Professor Ravi Silva’s audio interview with Alok Jha on the (UK) Guardian’s Oct. 14, 2011 Science Weekly podcast.)

In general, I found the descriptions of the science in this episode were not of the same standard as the previous two, which were very good.

The vignettes, as always, were problematic largely since they were internal monologues of some character who’s grappling with ethical issues and other social impacts of these technologies. Interestingly, men starred in the vignettes where the ‘big’ issues are covered: ethics of health care; longer life; access to energy sources; pollution from nanotechnology-enabled products; etc. The woman who starred in the vignettes from episode one (as I noted in my review) was concerned with cleanliness, tidiness, shopping, and privacy. I guess things don’t change that much in our future, especially in 2050 where nanotechnology protestors are putting up banners, spraypainting, and leafletting (almost as if it were 1968) to express their opposition (in episode three).

There was some interesting work being covered. They profiled Professor Ted Sargent, based at the University of Toronto, who’s doing some exciting work with solar cells (he wants to make them flexible and, even, paintable). His latest breakthrough is mentioned in my Sept. 20, 2011 posting.

Professor Vicki Colvin, Rice University in Texas, is working to purify water. The project is in Mexico and highlights the difficulties when water supplies are contaminated, in this case, with arsenic. (Here in the Pacific Northwest we tend to forget that access to fresh clean water is not easy in many parts of the world.) Colvin and her colleagues are working on a simple solution that can be implemented with some sand, gravel, a tube, and active nanoparticles. (Her work with the Environmental Nanoscience Initiative; a UK/US collaboration was mentioned in my Jan. 28, 2011 posting.)

The third project was focussed on soil remediation and a team from the University of Western Ontario headed by Professor Dennis O’Carroll. I have not come across O’Carroll’s work previously so this was a find for me. As you may or may not know, there are many sites with contaminated soil throughout North America and elsewhere. If successful, O’Carroll’s technique promises to remediate (rehabiltate) the soil without having to move massive amounts of soil and use big  equipment.

This episode featured more discussion about the risks and uncertainties associated with nanotechnology and its use. Unfortunately, I did not recognize the names and (one of my major pet peeves with this series) they either didn’t write out the names on screen or they flashed them briefly which meant that unless I recognized the names it was difficult to find out more about the experts.

I did recognize the mesocosm project at Duke University, which was featured here in my August 15, 2011 posting. The researchers are trying to understand what impact silver nanoparticles have on life. They spray silver nanoparticles in various mesocosms (they look like raised plant beds) and then track what happens to the plant, the soil, and the water supply as the silver nanoparticles cycle through.

There’s work in the UK examining air and the nanoparticles released through the use of internal combustion engines (cars/trucks) as well as our newly engineered nanoparticles. I’m glad to see this material in the episode, perhaps it will finally motivate some public discussion in Canada.