Tag Archives: electrochromic windows

Excellent electrochromic smart window performance with yolk-shell NiO (nitrogen oxide) nanospheres

Electrochromic windows hold great promise where energy savings are concerned. So far, it’s still just a promise but perhaps the research in this April 17, 2023 news item on phys.org will help realize it, Note: Links have been removed,

Researchers from Tsinghua University synthesized porous yolk-shell NiO nanospheres (PYS-NiO NSs) via a solvothermal and subsequent calcination process of Ni-MOF. As the large specific surface areas and hollow porous nanostructures were conducive to ionic transport, PYS-NiO NSs exhibited a fast coloring/bleaching speed (3.6/3.9 s per one coloring/bleaching cycle) and excellent cycling stability (82% of capacity retention after 3000 cycles). These superior electrochromic (EC) properties indicated that the PYS-NiO NSs was a promising candidate for high performance EC devices.

Electrochromic (EC) materials (ECMs) are defined as the materials which have reversible changes in their colors and optical properties (transmittance, reflectance, and absorption) under different external voltages. Over the past decades, ECMs show promising advantages and application prospects in many fields such as smart windows, adaptive camouflage, electronic displays, and energy storage, etc., because of their excellent optical modulation abilities.

This image doesn’t seem all that helpful (to me) in understanding the research,

Caption: Porous yolk-shell nanospheres exhibit a fast coloring/bleaching speed. Credit: Baoshun Wang, Tsinghua University

An April 17, 2023 Particuology (journal) news release on EurekAlert, which originated the news item, does provide more detail, Note: Links have been removed,

Transition metal oxides (TMOs) are one of the most important ECMs which have been widely studied. They have many advantages such as rich nanostructure design, simple synthesis process, high security, etc. Among them, nickel oxide (NiO) is an attractive anode ECM and has attracted extensive research interest due to its high optical contrast, high coloring efficiency, low cost, etc. However, NiO-based ECMs still face the challenges of long EC switching times and poor cycling life which are caused by their poor ionic/electronic diffusion kinetics and low electrical conductivity.

Metal-organic frameworks (MOFs) have attracted enormous attention, because of their high porosity and large surface areas, and could be adjusted to achieve different properties by selecting different metal ions and organic bridging ligands. Due to the porosity and long-range orderliness, MOFs can provide fast and convenient channels for small molecules and ions to insert and extract during the transformation process. Therefore, MOFs can be used as effective templates for the preparation of hollow and porous TMOs with high ion transport efficiency, excellent specific capacitance, and electrochemical activities.

So the authors proposed a new strategy to design a kind of NiO with hollow and porous structure to obtain excellent EC performance and cyclic stability. As a proof-of-concept demonstration, the authors successfully synthesized MOFs-derived porous yolk-shell NiO nanospheres (PYS-NiO NSs) which exhibited excellent EC performance. Ni-organic framework spheres were prepared by a simple solvothermal method and then converted to PYS-NiO NSs by thermal decomposition. The PYS-NiO NSs exhibited relatively high specific surface areas and stable hollow nanostructures, which not only provided a large contact area between active sites and electrolyte ions in the EC process but also helped the NiO to accommodate large volume changes without breaking. Besides, the PYS-NiO NSs also shortened the ionic diffusion length and provided efficient channels for transferring electronics and ions. In addition, the coupling with carbon also rendered the PYS-NiO NSs with improved electronic conductivity and obtained better EC performance. The PYS-NiO NSs exhibited a fast coloring/bleaching speed (3.6/3.9 s). Besides, PYS-NiO NSs also exhibited excellent cycling stability (82% of capacity retention after 3000 cycles). These superior EC properties indicate that the PYS-NiO NSs is a promising candidate for high-performance EC devices. The as-prepared PYS-NiO NSs are believed to be a promising candidate for smart windows, displays, antiglare rearview mirrors, etc. More importantly, this work provides a new and feasible strategy for the efficient preparation of ECMs with fast response speed and high cyclic stability.

Particuology (IF=3.251) is an interdisciplinary journal that publishes frontier research articles and critical reviews on the discovery, formulation and engineering of particulate materials, processes and systems. Topics are broadly relevant to the production of materials, pharmaceuticals and food, the conversion of energy resources, and protection of the environment. For more information, please visit: https://www.journals.elsevier.com/particuology.

Here’s a link to and a citation for the paper, Note: There is an unusually long lead time between online access and print access,

Novel self-assembled porous yolk-shell NiO nanospheres with excellent electrochromic performance for smart windows by Baoshun Wang, Ya Huang, Siming Zhao, Run Li, Di Gao, Hairong Jiang, Rufan Zhang. Particuology Volume 84, January 2024, Pages 72-80 DOI: https://doi.org/10.1016/j.partic.2023.03.007 Available online: April 17, 2023

This paper is open access.

Spray-on coatings for cheaper smart windows

An August 6, 2020 RMIT University (Australia) press release (also on EurekAlert but published August 5, 2020) by Gosia Kaszubska announces a coating that makes windows ‘smart’,

A simple method for making clear coatings that can block heat and conduct electricity could radically cut the cost of energy-saving smart windows and heat-repelling glass [electrochromic windows?].

The spray-on coatings developed by researchers at RMIT are ultra-thin, cost-effective and rival the performance of current industry standards for transparent electrodes.

Combining the best properties of glass and metals in a single component, a transparent electrode is a highly conductive clear coating that allows visible light through.

The coatings – key components of technologies including smart windows, touchscreen displays, LED lighting and solar panels – are currently made through time-consuming processes that rely on expensive raw materials.

The new spray-on method is fast, scalable and based on cheaper materials that are readily available.

The method could simplify the fabrication of smart windows, which can be both energy-saving and dimmable, as well as low-emissivity glass, where a conventional glass panel is coated with a special layer to minimise ultraviolet and infrared light.

Lead investigator Dr Enrico Della Gaspera said the pioneering approach could be used to substantially bring down the cost of energy-saving windows and potentially make them a standard part of new builds and retrofits.

“Smart windows and low-E glass can help regulate temperatures inside a building, delivering major environmental benefits and financial savings, but they remain expensive and challenging to manufacture,” said Della Gaspera, a senior lecturer and Australian Research Council DECRA Fellow at RMIT.

“We’re keen to collaborate with industry to further develop this innovative type of coating.

“The ultimate aim is to make smart windows much more widely accessible, cutting energy costs and reducing the carbon footprint of new and retrofitted buildings.”

The new method can also be precisely optimised to produce coatings tailored to the transparency and conductivity requirements of the many different applications of transparent electrodes.

Global demand for smart glazing

The global market size for smart glass and smart windows is expected to reach $6.9 billion by 2022, while the global low-E glass market is set to reach an estimated $39.4 billion by 2024.

New York’s Empire State Building reported energy savings of $US2.4 million and cut carbon emissions by 4,000 metric tonnes after installing smart glass windows.

Eureka Tower in Melbourne features a dramatic use of smart glass in its “Edge” tourist attraction, a glass cube that projects 3m out of the building and suspends visitors 300m over the city. The glass is opaque as the cube moves out over the edge of the building and becomes clear once fully extended.

First author Jaewon Kim, a PhD researcher in Applied Chemistry at RMIT,  said the next steps in the research were developing precursors that will decompose at lower temperatures, allowing the coatings to be deposited on plastics and used in flexible electronics, as well as producing larger prototypes by scaling up the deposition.

“The spray coater we use can be automatically controlled and programmed, so fabricating bigger proof-of-concept panels will be relatively simple,” he said.

Caption: The ultra-thin clear coatings are made with a new spray-on method that is fast, cost-effective and scalable. Credit: RMIT University

That is an impressive level of transparency. As per usual, here’s a link to and a citation for the paper (should you wish to explore further),

Ultrasonic Spray Pyrolysis of Antimony‐Doped Tin Oxide Transparent Conductive Coatings by Jaewon Kim, Billy J. Murdoch, James G. Partridge, Kaijian Xing, Dong‐Chen Qi, Josh Lipton‐Duffin, Christopher F. McConville, Joel van Embden, Enrico Della Gaspera. Advanced Materials Interfaces DOI: https://doi.org/10.1002/admi.202000655 First published: 05 August 2020

This paper is behind a paywall.

View Dynamic Glass—intelligent windows sold commercially

At last, commercially available ‘smart’, that is, electrochromic windows.

An April 17, 2018 article by Conor Shine for Dallas News describes a change at the Dallas Fort Worth (DFW) International Airport that has cooled things down,

At DFW International Airport, the coolest seats in the house can be found near Gate A28.

That’s where the airport, working with California-based technology company View, has replaced a bank of tarmac-facing windows with panes coated in microscopic layers of electrochromic ceramic that significantly reduce the amount of heat and glare coming into the terminal.

The technology, referred to as dynamic glass, uses an electrical current to change how much light is let in and has been shown to reduce surface temperatures on gate area seats and carpets by as much as 15 degrees compared to standard windows. All that heat savings add up, with View estimating its product can cut energy costs by as much as 20 percent when the technology is deployed widely in a building.

At DFW Airport, the energy bill runs about $18 million per year, putting the potential savings from dynamic glass into the hundreds of thousands, or even millions of dollars, annually.

Besides the money, it’s an appealing set of characteristics for DFW Airport, which is North America’s only carbon-neutral airport and regularly ranks among the top large airports for customer experience in the world.

After installing the dynamic glass near Gate A28 and a nearby Twisted Root restaurant in September at a cost of $49,000, the airport is now looking at ordering more for use throughout its terminals, although how many and at what cost hasn’t been finalized yet.

On a recent weekday morning, the impact of the dynamic glass was on full display. As sunlight beamed into Gate A25, passengers largely avoided the seats near the standard windows, favoring shadier spots a bit further into the terminal.

A few feet away, the bright natural light takes on a subtle blue hue and the temperature near the windows is noticeably cooler. There, passengers seemed to pay no mind to sitting in the sun, with window-adjacent seats filling up quickly.

As View’s Jeff Platón, the company’s vice president of marketing, notes in the video, there are considerable savings to be had when you cut down on air conditioning,

View’s April 17, 2018 news release (PDF) about a study of their technology in use at the airport provides more detail,

View®, the leader in dynamic glass, today announced the results of a study on the impact of in-terminal passenger experience and its correlation to higher revenues and reduced operational expenses.The study, conducted at Dallas Fort Worth International Airport (DFW), found that terminal windows fitted with View Dynamic Glass overwhelmingly improved passenger comfort over conventional glass, resulting in an 83 percent increase in passenger dwell time at a preferred gate seat and a 102 percent increase in concession spending. The research study was conducted by DFW Airport, View, Inc., and an independent aviation market research group.

It’s been a long time (I’ve been waiting about 10 years) but it seems that commercially available ‘smart’ glass is here—at the airport, anyway.

ht/ April 20, 2018 news item on phys.org

‘Smart’ windows from Australia

My obsession with smart windows has been lying dormant until now. This February 25, 2018 RMIT University (Australia) press release on EurekAlert has reawkened it,

Researchers from RMIT University in Melbourne Australia have developed a new ultra-thin coating that responds to heat and cold, opening the door to “smart windows”.

The self-modifying coating, which is a thousand times thinner than a human hair, works by automatically letting in more heat when it’s cold and blocking the sun’s rays when it’s hot.

Smart windows have the ability to naturally regulate temperatures inside a building, leading to major environmental benefits and significant financial savings.

Lead investigator Associate Professor Madhu Bhaskaran said the breakthrough will help meet future energy needs and create temperature-responsive buildings.

“We are making it possible to manufacture smart windows that block heat during summer and retain heat inside when the weather cools,” Bhaskaran said.

“We lose most of our energy in buildings through windows. This makes maintaining buildings at a certain temperature a very wasteful and unavoidable process.

“Our technology will potentially cut the rising costs of air-conditioning and heating, as well as dramatically reduce the carbon footprint of buildings of all sizes.

“Solutions to our energy crisis do not come only from using renewables; smarter technology that eliminates energy waste is absolutely vital.”

Smart glass windows are about 70 per cent more energy efficient during summer and 45 per cent more efficient in the winter compared to standard dual-pane glass.

New York’s Empire State Building reported energy savings of US$2.4 million and cut carbon emissions by 4,000 metric tonnes after installing smart glass windows. This was using a less effective form of technology.

“The Empire State Building used glass that still required some energy to operate,” Bhaskaran said. “Our coating doesn’t require energy and responds directly to changes in temperature.”

Co-researcher and PhD student Mohammad Taha said that while the coating reacts to temperature it can also be overridden with a simple switch.

“This switch is similar to a dimmer and can be used to control the level of transparency on the window and therefore the intensity of lighting in a room,” Taha said. “This means users have total freedom to operate the smart windows on-demand.”

Windows aren’t the only clear winners when it comes to the new coating. The technology can also be used to control non-harmful radiation that can penetrate plastics and fabrics. This could be applied to medical imaging and security scans.

Bhaskaran said that the team was looking to roll the technology out as soon as possible.

“The materials and technology are readily scalable to large area surfaces, with the underlying technology filed as a patent in Australia and the US,” she said.

The research has been carried out at RMIT University’s state-of-the-art Micro Nano Research Facility with colleagues at the University of Adelaide and supported by the Australian Research Council.

How the coating works

The self-regulating coating is created using a material called vanadium dioxide. The coating is 50-150 nanometres in thickness.

At 67 degrees Celsius, vanadium dioxide transforms from being an insulator into a metal, allowing the coating to turn into a versatile optoelectronic material controlled by and sensitive to light.

The coating stays transparent and clear to the human eye but goes opaque to infra-red solar radiation, which humans cannot see and is what causes sun-induced heating.

Until now, it has been impossible to use vanadium dioxide on surfaces of various sizes because the placement of the coating requires the creation of specialised layers, or platforms.

The RMIT researchers have developed a way to create and deposit the ultra-thin coating without the need for these special platforms – meaning it can be directly applied to surfaces like glass windows.

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

Insulator–metal transition in substrate-independent VO2 thin film for phase-change device by Mohammad Taha, Sumeet Walia, Taimur Ahmed, Daniel Headland, Withawat Withayachumnankul, Sharath Sriram, & Madhu Bhaskaran. Scientific Reportsvolume 7, Article number: 17899 (2017) doi:10.1038/s41598-017-17937-3 Published online: 20 December 2017

This paper is open access.

For anyone interested in more ‘smart’ windows, you can try that search term or ‘electrochromic’, ‘photochromic’, and ‘thermochromic’ , as well.

Self-shading electrochromic windows from the Massachusetts Institute of Technology

It’s been a while since I’ve had a story about electrochromic windows and I’ve begun to despair that they will ever reach the marketplace. Happily, the Massachusetts Institute of Technology (MIT) has supplied a ray of light (intentional wordplay). An Aug. 11, 2016 news item on Nanowerk makes the announcement,

A team of researchers at MIT has developed a new way of making windows that can switch from transparent to opaque, potentially saving energy by blocking sunlight on hot days and thus reducing air-conditioning costs. While other systems for causing glass to darken do exist, the new method offers significant advantages by combining rapid response times and low power needs.

Once the glass is switched from clear to dark, or vice versa, the new system requires little to no power to maintain its new state; unlike other materials, it only needs electricity when it’s time to switch back again.

An Aug. 11, 2016 MIT news release (also on EurekAlert), which originated the news item, explains the technology in more detail,

The new discovery uses electrochromic materials, which change their color and transparency in response to an applied voltage, Dinca [MIT professor of chemistry Mircea Dinca] explains. These are quite different from photochromic materials, such as those found in some eyeglasses that become darker when the light gets brighter. Such materials tend to have much slower response times and to undergo a smaller change in their levels of opacity.

Existing electrochromic materials suffer from similar limitations and have found only niche applications. For example, Boeing 787 aircraft have electrochromic windows that get darker to prevent bright sunlight from glaring through the cabin. The windows can be darkened by turning on the voltage, Dinca says, but “when you flip the switch, it actually takes a few minutes for the window to turn dark. Obviously, you want that to be faster.”

The reason for that slowness is that the changes within the material rely on a movement of electrons — an electric current — that gives the whole window a negative charge. Positive ions then move through the material to restore the electrical balance, creating the color-changing effect. But while electrons flow rapidly through materials, ions move much more slowly, limiting the overall reaction speed.

The MIT team overcame that by using sponge-like materials called metal-organic frameworks (MOFs), which can conduct both electrons and ions at very high speeds. Such materials have been used for about 20 years for their ability to store gases within their structure, but the MIT team was the first to harness them for their electrical and optical properties.

The other problem with existing versions of self-shading materials, Dinca says, is that “it’s hard to get a material that changes from completely transparent to, let’s say, completely black.” Even the windows in the 787 can only change to a dark shade of green, rather than becoming opaque.

In previous research on MOFs, Dinca and his students had made material that could turn from clear to shades of blue or green, but in this newly reported work they have achieved the long-sought goal of producing a coating that can go all the way from perfectly clear to nearly black (achieved by blending two complementary colors, green and red). The new material is made by combining two chemical compounds, an organic material and a metal salt. Once mixed, these self-assemble into a thin film of the switchable material.

“It’s this combination of these two, of a relatively fast switching time and a nearly black color, that has really got people excited,” Dinca says.

The new windows have the potential, he says, to do much more than just preventing glare. “These could lead to pretty significant energy savings,” he says, by drastically reducing the need for air conditioning in buildings with many windows in hot climates. “You could just flip a switch when the sun shines through the window, and turn it dark,” or even automatically make that whole side of the building go dark all at once, he says.

While the properties of the material have now been demonstrated in a laboratory setting, the team’s next step is to make a small-scale device for further testing: a 1-inch-square sample, to demonstrate the principle in action for potential investors in the technology, and to help determine what the manufacturing costs for such windows would be.

Further testing is also needed, Dinca says, to demonstrate what they have determined from preliminary testing: that once the switch is flipped and the material changes color, it requires no further power to maintain its new state. No extra power is needed until the switch is flipped to turn the material back to its former state, whether clear or opaque. Many existing electrochromic materials, by contrast, require a continuous voltage input.

In addition to smart windows, Dinca says, the material could also be used for some kinds of low-power displays, similar to displays like electronic ink (used in devices such as the Kindle and based on MIT-developed technology) but based on a completely different approach.

Not surprisingly perhaps, the research was partly funded by an organization in a region where such light-blocking windows would be particularly useful: The Masdar Institute, based in the United Arab Emirates, through a cooperative agreement with MIT. The research also received support from the U.S. Department of Energy, through the Center for Excitonics, an Energy Frontier Center.

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

Transparent-to-Dark Electrochromic Behavior in Naphthalene-Diimide-Based Mesoporous MOF-74 Analogs by Khalid AlKaabi, Casey R. Wade, Mircea Dincă. Chem, Volume 1, Issue 2, 11 August 2016, Pages 264–272 doi:10.1016/j.chempr.2016.06.013

This paper is behind a paywall.

For those curious about the windows, there’s this .gif from MIT,

MIT_ElectrochromicWindows

Smart windows need anti-aging treatments

I’ve long been interested in electrochromic windows and this is the first I’ve heard of a problem with limited lifespans. Here’s more from an Oct. 1, 2015 news item on Nanowerk (Note: A link has been removed),

Electrochromic windows, so-called ‘smart windows’, share a well-known problem with rechargeable batteries – their limited lifespan. Researchers at Uppsala University [Sweden] have now worked out an entirely new way to rejuvenate smart windows which have started to show signs of age. The study, published in Nature Materials (“Eliminating degradation and uncovering ion-trapping dynamics in electrochromic WO3 thin films”), may open the way to other areas of application.

An Oct. 1, 2015 Uppsala University press release (also on EurekAlert), which originated the new item, describes previous work on electrochromic windows to provide context for the current research,

The electrochromic smart windows are controlled electrically. This kind of window is the result of research carried out at Uppsala University. Commercial production has recently been started by the company ChromoGenics AB.

The electrochromic smart window is made up of a series of thin layers on top of each other. The most important of these are two layers of tungsten oxide and nickel oxide, both about a third of a micrometer thick. They are separated by an electrolyte layer. The window’s opacity to visible light and solar energy varies when an electrical current flows between the oxide layers.

“The principle is the same as for an electric battery. Here the tungsten-oxide is the cathode and the nickel-oxide the anode. Opacity depends on how much the ‘battery’ is charged,” says Rui-Tao Wen, a doctoral student who carried out the study as part of his thesis.

The lifespan of both electric batteries and electrochromic smart windows is a well-known problem. They need to work after being charged and discharged many times if they are to be really profitable.

In the study, the researchers show that an electrochromic tungsten oxide layer which has been charged and discharged many times and has started to lose its capacity can be restored to its former high capacity. This is achieved by running a weak electric current through it while it is in light mode. This takes about an hour. In this way, the electric charge which has ‘fastened’ in the material is removed and the tungsten oxide layer is like new again.

“This is a new way to rejuvenate smart windows so that they last much longer. And the same principle might perhaps be used for electric batteries,” says Claes-Göran Granqvist, senior professor at the Ångström Laboratory, Uppsala University and one of the authors of the study.

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

Eliminating degradation and uncovering ion-trapping dynamics in electrochromic WO3 thin films by Rui-Tao Wen, Claes G. Granqvist, & Gunnar A. Niklasson. Nature Materials 14, 996–1001 (2015) doi:10.1038/nmat4368 Published online 10 August 2015

This paper is behind a paywall.

Smart windows from Texas (US)

I’ve been waiting for ‘smart’ windows and/or self-cleaning windows since 2008. While this research on ‘smart’ windows at the University of Texas at Austin looks promising I suspect it will be years before these things are in the marketplace. A July 22, 2015 news item on Nanotechnology Now announces the latest research,

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for heating and cooling buildings.

In 2013, chemical engineering professor Delia Milliron and her team became the first to develop dual-band electrochromic materials that blend two materials with distinct optical properties for selective control of visible and heat-producing near-infrared light (NIR). In a 2013 issue of Nature, Milliron’s research group demonstrated how, using a small jolt of electricity, a nanocrystal material could be switched back and forth, enabling independent control of light and energy.

A July 23, 2015 University of Texas at Austin news release, which originated the news item, provides more details about the research which has spawned two recently published papers,

The team now has engineered two new advancements in electrochromic materials — a highly selective cool mode and a warm mode — not thought possible several years ago.

The cool mode material is a major step toward a commercialized product because it enables control of 90 percent of NIR and 80 percent of the visible light from the sun and takes only minutes to switch between modes. The previously reported material could require hours.

To achieve this high performance, Milliron and a team, including Cockrell School postdoctoral researcher Jongwook Kim and collaborator Brett Helms of the Lawrence Berkeley National Lab, developed a new nanostructured architecture for electrochromic materials that allows for a cool mode to block near-infrared light while allowing the visible light to shine through. This could help reduce energy costs for cooling buildings and homes during the summer. The researchers reported the new architecture in Nano Letters on July 20.

“We believe our new architected nanocomposite could be seen as a model material, establishing the ideal design for a dual-band electrochromic material,” Milliron said. “This material could be ideal for application as a smart electrochromic window for buildings.”

In the paper, the team demonstrates how the new material can strongly and selectively modulate visible light and NIR by applying a small voltage.

To optimize the performance of electrochromics for practical use, the team organized the two components of the composite material to create a porous interpenetrating network. The framework architecture provides channels for transport of electronic and ionic change. This organization enables substantially faster switching between modes.
Smart Window

The researchers are now working to produce a similarly structured nanocomposite material by simple methods, suitable for low-cost manufacturing.

In a second research paper, Milliron and her team, including Cockrell School graduate student Clayton Dahlman, have reported a proof-of-concept demonstrating how they can achieve optical control properties in windows from a well-crafted, single-component film. The concept includes a simple coating that creates a new warm mode, in which visible light can be blocked, while near-infrared light can enter. This new setting could be most useful on a sunny winter day, when an occupant would want infrared radiation to pass into a building for warmth, but the glare from sunlight to be reduced.

In this paper, published in the Journal of the American Chemical Society, Milliron proved that a coating containing a single component ­— doped titania nanocrystals — could demonstrate dynamic control over the transmittance of solar radiation. Because of two distinct charging mechanisms found at different applied voltages, this material can selectively block visible or infrared radiation.

“These two advancements show that sophisticated dynamic control of sunlight is possible,” Milliron said. “We believe our deliberately crafted nanocrystal-based materials could meet the performance and cost targets needed to progress toward commercialization of smart windows.”

Interestingly, the news release includes this statement,

The University of Texas at Austin is committed to transparency and disclosure of all potential conflicts of interest. The lead UT investigator involved with this project, Delia Milliron, is the chief scientific officer and owns an equity position in Heliotrope Technologies, an early-stage company developing new materials and manufacturing processes for electrochromic devices with an emphasis on energy-saving smart windows. Milliron is associated with patents at Lawrence Berkeley National Laboratory licensed to Heliotrope Technologies. Collaborator Brett Helms serves on the scientific advisory board of Heliotrope and owns equity in the company.

Here are links to and citations for the two papers,

Nanocomposite Architecture for Rapid, Spectrally-Selective Electrochromic Modulation of Solar Transmittance by Jongwook Kim, Gary K. Ong, Yang Wang, Gabriel LeBlanc, Teresa E. Williams, Tracy M. Mattox, Brett A. Helms, and Delia J. Milliron. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.5b02197 Publication Date (Web): July 20, 2015

Copyright © 2015 American Chemical Society

Spectroelectrochemical Signatures of Capacitive Charging and Ion Insertion in Doped Anatase Titania Nanocrystals by Clayton J. Dahlman, Yizheng Tan, Matthew A. Marcus, and Delia J. Milliron. J. Am. Chem. Soc., 2015, 137 (28), pp 9160–9166 DOI: 10.1021/jacs.5b04933 Publication Date (Web): July 8, 2015

Copyright © 2015 American Chemical Society

These papers are behind paywalls.

Smarter ‘smart’ windows

It seems to me we may have to find a new way to discuss ‘smart’ windows as there’s only one more category after the comparative  ‘smarter’ and that’s the superlative ‘smartest’. Lawrence Berkeley National Laboratory (Berkeley Lab), please, let’s stop the madness now! That said, the Berkeley Lab issued an Aug. 14, 2013 news release  (also on EurekAlert) about it’s latest work on raising the IQ of smart windows,

Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have designed a new material to make smart windows even smarter. The material is a thin coating of nanocrystals embedded in glass that can dynamically modify sunlight as it passes through a window. Unlike existing technologies, the coating provides selective control over visible light and heat-producing near-infrared (NIR) light, so windows can maximize both energy savings and occupant comfort in a wide range of climates.

Milliron’s research group is already well known for their smart-window technology that blocks NIR without blocking visible light. The technology hinges on an electrochromic effect, where a small jolt of electricity switches the material between NIR-transmitting and NIR-blocking states. This new work takes their approach to the next level by providing independent control over both visible and NIR light. The innovation was recently recognized with a 2013 R&D 100 Award and the researchers are in the early stages of commercializing their technology.

Independent control over NIR light means that occupants can have natural lighting indoors without unwanted thermal gain, reducing the need for both air-conditioning and artificial lighting. The same window can also be switched to a dark mode, blocking both light and heat, or to a bright, fully transparent mode.

“We’re very excited about the combination of unique optical function with the low-cost and environmentally friendly processing technique,” said Llordés, a project scientist working with Milliron. “That’s what turns this ‘universal smart window’ concept into a promising competitive technology.”

Here’s the specific technology that’s been developed, from the news release,

At the heart of their technology is a new “designer” electrochromic material, made from nanocrystals of indium tin oxide embedded in a glassy matrix of niobium oxide. The resulting composite material combines two distinct functionalities—one providing control over visible light and the other, control over NIR—but it is more than the sum of its parts. The researchers found a synergistic interaction in the tiny region where glassy matrix meets nanocrystal that increases the potency of the electrochromic effect, which means they can use thinner coatings without compromising performance. The key is that the way atoms connect across the nanocrystal-glass interface causes a structural rearrangement in the glass matrix. The interaction opens up space inside the glass, allowing charge to move in and out more readily. Beyond electrochromic windows, this discovery suggests new opportunities for battery materials where transport of ions through electrodes can be a challenge.

I notice they’re using indium, one of the ‘rare earths’. Last I heard, China, one of the main sources for ‘rare earths’, was limiting its exports so this seems like an odd choice of material. Perhaps now they’ve proved this can be done,  they’ll research for easily available substitutes. Here’s a link to and a citation for the published paper,

Tunable near-infrared and visible-light transmittance in nanocrystal-in-glass composites by Anna Llordés, Guillermo Garcia, Jaume Gazquez, & Delia J. Milliron. Nature 500, 323–326 (15 August 2013) doi:10.1038/nature12398 Published online 14 August 2013

Finally, the researchers have provided an illustration of indium tin oxide nanocrystals,

Nanocrystals of indium tin oxide (shown here in blue) embedded in a glassy matrix of niobium oxide (green) form a composite material that can switch between NIR-transmitting and NIR-blocking states with a small jolt of electricity. A synergistic interaction in the region where glassy matrix meets nanocrystal increases the potency of the electrochromic effect. Courtesy Berkeley Lab

Nanocrystals of indium tin oxide (shown here in blue) embedded in a glassy matrix of niobium oxide (green) form a composite material that can switch between NIR-transmitting and NIR-blocking states with a small jolt of electricity. A synergistic interaction in the region where glassy matrix meets nanocrystal increases the potency of the electrochromic effect. Courtesy Berkeley Lab

Liquid solar blocker from Ontario’s Hy-Power Nano

Hy-Power Nano, mentioned in my Aug. 15, 2012 posting, has announced its first nanotechnology-enabled product and it’s a coating product for windows. From the Sept. 3, 2012 news item by Will Soutter item on Azonano,

Hy-Power Nano, the subsidiary of South Ontario-based [Canada] Hy-Power Coatings, engaged in developing nanocoating products characterized by thermal insulation and a solar blocking capability has introduced its first product labeled the Hy-Power Clear Liquid Solar Blocker.

The launch of the solar blocker represents a significant milestone in the company’s endeavors towards the development of nanotechnology-based coating products. The product was demonstrated in Mississauga at the International Conference Centre to a group of customers. The product is the output of two-and-a-half years of labor initiated after Hy-Power Nano President and CEO, Joseph Grzyb, envisaged the potential of leveraging their 46 years of expertise in industrial coating in combination with nanotechnology.

Hy-Power Nano’s Aug. 31, 2012 product announcement offers this comment from the company’s president, Joseph Grzyb,

“While we all love sunlight, ultraviolet (UV) rays can be damaging and infrared (IR) rays are a source of energy costs,” says Joseph Grzyb, President and CEO of Hy-Power Nano. “Our Clear Liquid Solar Blocker is so clear you can’t see it on glass, yet it blocks 99.99 per cent of UV and 40 per cent of infrared rays. Since the product is liquid-based, it can be applied on a variety of glass surfaces and geometries.”

“There are many applications for this product. For example, for retailers, that means products in windows won’t fade from sunlight while allowing customers a completely unobstructed view of the goods in the window. Skylights coated with our product allow people to enjoy the comfort and natural light without any negative impacts. There are actually quite a range of needs addressed by this product,” adds Grzyb.

There’s a lot of research interest in windows these days and it’s not just in Canada. This Aug. 27, 2012 Nanowerk Spotlight essay by Michael Berger offers an overview of some of the latest work,

Buildings and other man-made structures consume as much as 30-40% of the primary energy in the world, mainly for heating, cooling, ventilation, and lighting. In particular, air conditioners are responsible for a large proportion of the energy usage in the US: 13% in 2006 and 10% in 2020 (projected) of the total primary energy. Air conditioning in China is 40-60% of a building’s energy consumption (the exact figure depends on the area of the building), and overall, accounts for 30% of the total primary energy available. These figures will grow very rapidly with urbanization development.

“Smart window” is a term that refers to a glass window that allows intelligent control of the amount of light and heat passing though. This control is made possible by an external stimulus such as electrical field (electrochromic), temperature (thermochromic), ultraviolet irradiation (photochromic) and reductive or oxidizing gases (gasochromic). These technologies save energy, address CO2 concerns, improve comfort levels, and have economic benefits.

One of these days I’d like to see a study or two about the occupational health and safety issues for people who produce and apply coatings such as this one from Hy-Power.

Electrochromic windows and censorship/communication deficiencies

It was an unexpected response to a series of follow-up questions about electrochromic windows at the University of British Columbia’s (UBC) Centre for Interactive Research on Sustainability (CIRS) that has* given me the excuse to discuss censorship and science in Canada.

I’ll start with the windows. I participated in a pre-AAAS (American Association for the Advancement of Science) 2012 annual meeting event in February held by the University of British Columbia. The event was a tour of UBC’s relatively new (opened Nov. 2011) CIRS facility. It was very popular and there were at least 40 of us present.Here’s a little more information from the CIRS About page,

CIRS activities have a regional focus and a global reach. Located on the UBC campus in Vancouver, British Columbia, CIRS is a hub of excellence around green design and building operations practices. We bring thought leaders from UBC and our region together to create and test solutions that work at home, and then share our experiences and knowledge with the public and professionals from across our province and around the world. [emphasis mine] A typical day at CIRS generates many interesting conversations and ideas.

Documenting our activities and communicating our lessons and successes are priorities at CIRS.

We use this website as our primary communication vehicle, showcasing the building design and construction process and the exciting research underway at CIRS. Through this website we aim to build a community of professional and interested people who can connect, share ideas and further accelerate sustainability. [emphasis mine]

We also connect with individuals face-to-face as much as possible through symposiums, workshops, building tours and other events held in the interactive spaces at CIRS.

During the course of the tour there was some discussion about community-building, outreach, etc. and we were informed that the facility is testing a couple of electrochromic windows, amongst other things. Later, I did ask for more information about the electrochromic windows at CIRS and was promptly rewarded with this from Ann L. Campbell,

My colleague Brian Lin passed along your question regarding the electrochromic windows at UBC. Here is the response I received from Alberto Cayuela, the Associate Director of CIRS. He kindly answered my question (what are these windows?) as well as your question regarding their use at CIRS:

We have a limited number of electrochromic windows in the building (fourth floor southwest corner). We are planning to do some research on them in partnership with BC Hydro. Essentially this technology enables the glass to darken or light when a low-voltage electric current is applied to the glass. There are energy benefits associated with blocking or letting heat through windows depending on the time of the year and desired outcome.

I invite you to join the community at www.cirs.ubc.ca where we will post research projects and results as they are undertaken.

The answer excited my curiosity since I’ve written about ‘smart’ windows a number of times, most recently in a Sept. 16, 2011 posting about Boris Lamontagne’s work at the Canada National Research Council and in a Sept. 7, 2011 posting about WANDA, the nanocrystal robot and its role in one of the US Dept. of Energy’s projects with electrochromic windows so I sent back more questions.

After waiting two weeks for a reply, I resent the questions and got a response this morning,

Dear Maryse,

I’m sorry that we are not going to be able to help you with your questions right now. There is no other information available beyond what I sent previously and what is in the online CIRS Technical Manual (and I know that is not much).

Good luck with your blog. I’m sorry we are not able to contribute.

Warm regards,

Ann

Ann L. Campbell
Manager of Communications
UBC Sustainability Initiative

They aren’t able to answer these questions, eh? From my Feb. 21 and March 6, 2012 email request:

Perhaps you could direct me to someone who could answer more specific questions about these windows for publication in my blog. It’s a topic I’ve mentioned on a number of occasions and am hugely excited to hear about this research. Here are the questions:

Who is answering these questions? (Perhaps include a brief bio.?)

Are these windows both electrochromic & photochromic?

Where did you get these windows from and what specific technology do they demonstrate? Could you describe that technology in more detail? e.g. Switch Materials, a local company offers electrochromic and photochromic films for windows or Boris Lamontagne at the NRC has a project with glass that includes curling electrodes, etc.

Exactly how big are these electrochromic windows and what percentage of the windows in the CIRS are electrochromic?

What kind of research are you doing with regard to these windows? Are you measuring their effectiveness, their aesthetic impact, the quality of light and its impact on wellbeing, etc.?

How many pilot programmes for electrochromic/photochromic windows are there in BC? (Is the one at CIRS the only one?)

Is BC Hydro hoping to encourage consumer use of these windows? Are they hoping this is the wave of the future?

I’m not sure why they weren’t willing answer at least a few of these questions, which seem relatively unexceptional, or even supply a reason of some kind for the failure to share information. It seems odd given their mandate which emphasizes outreach and communication.

I did look at the technical manual for the building and Campbell quite correctly noted that it doesn’t provide answers to my questions. I checked the information on lighting and searched for the terms ‘windows’ and ‘electrochromic windows’ in the building manual (the search function does not seem to be working).

The response from Campbell is a pretty standard bureaucratic response (I must give her credit for being significantly more polite than many others). The problem starts with the organization’s stated mandate of  ‘sharing’. I am assuming the intentions are good but the execution is a problem as it often is with mandates that include words such as  ‘sharing’, ‘interactivity’, ‘openness’, and/or ‘community building’, etc. in situations where that is not always possible.

There is another issue: a communications manager is acting as an interface or gatekeeper to the scientists. Note:  I’m not familiar with UBC or CIRS policies regarding direct contact with scientists. Campbell may have been acting as an interface or gatekeeper as a consequence of my initial request which was made to Brian Lin of UBC’s Public Affairs group, although the result seems roughly the same whether Campbell’s role as gatekeeper was intentional or accidental. It should be noted that she never explicitly denied access to a scientist and even if I did get access, there is no guarantee I would have received any answers (scientists aren’t always willing to talk). Still, could Campbell’s response be described as censorship? Before I try to answer that question, I’m going to touch on another situation.

Over the last few years the Canadian government has intentionally instituted a new strategy of insisting a communications professional act as an interface to government scientists. This ‘new’ practice has become a sore point for Canadian journalists who have described it as ‘muzzling scientists’. I certainly haven’t been happy about this added hurdle to getting questions answered as I noted most recently in my Jan. 24, 2012 posting but I’m still considering whether the practice could be described as censorship or not.

The AAAS 2012 annual meeting in Vancouver hosted an event about the ‘science muzzle’ and it was SRO (standing room only). I didn’t attend largely because it had a certain fevered quality I associate with mobs but it has stimulated a fair degree of discussion. Here’s a description of the session from the Professional Institute of the Public Service of Canada webpage titled Unmuzzling Government Scientists,

 Across Canada, journalists are being denied access to publicly funded scientists and the research community is frustrated with the way government scientists are being muzzled. Some observe that it is part of a trend that has seen the Canadian government tighten control over how and when federal scientists interact with the media. As a result, media inquiries are delayed, and scientists are less present in coverage of research in Canada.

In 2008, Environment Canada ordered its scientists to refer all media queries to Ottawa, where communications officers and strategists would decide if the scientist could respond and help craft “approved media lines”.

Stories written for the CBC, Postmedia news, the journal Nature and others have then revealed how these communication restrictions had spread to other government departments.

And the situation is somewhat similar in the United States. A recent article in the Columbia Journalism Review details how restrictive practices established by George W. Bush’s administration still hold under the current government.

This panel will be an occasion to better understand the friction between the media and the governments.

Are the tightened communication strategies symptomatic of a worldwide trend in public and private sectors? Are they justified?

How do obstructions in communications with scientists compromise science research progression and undermine democracy? And in the end, what can be done to improve the situation? 

The February 17, 2012 posting on the Scientific Canadian blog provides some insight into these ‘obstructions’ (I have removed some links),

 I’ve had my own experiences with the phenomenon. Last spring, I interviewed Environment Canada scientist David Tarasick about how cold stratospheric temperatures led to more ozone depletion than usual in 2011. Although he was quite willing to talk to me, government policy required my questions to be submitted in advance by e-mail, and his written responses vetted by Environment Canada’s media relations department; I never did speak to him in person, and couldn’t ask any follow-up questions. More importantly, the whole process took about two weeks. If I had been writing for a daily publication instead of a monthly, the delay would have been unacceptably long. By contrast, his co-author on the paper, the University of Toronto’s Kaley Walker, was able to talk to me on the phone within 24 hours. But I was lucky; a few months later Postmedia News was prevented from speaking with Tarasick altogether.

Even though Environment Canada communication professionals eventually refused access to Tarasick, does that action constitute censorship? According to David Bruggeman’s Mar. 3, 2012 posting on his Pasco Phronesis blog, the answer is no,

 I am not trying to defend the Canadian government.  There is plenty to disagree with about their policies of limiting the dissemination of government conducted research results.  But because they allow this research to be published, the problem is one of transparency, and not of censorship. It doesn’t help those seeking to change the policies to call the bad behavior something it isn’t.  Utilize Canadian open records and open government laws (whatever might be the equivalent of the Freedom of Information Act) to fight for the information.

It might be helpful to know this about David Bruggeman, from Pasco Phronesis blog About page,

I have over 12 years experience in U.S. federal science and technology policy, conducting research and analysis in many subjects for the National Academies and other organizations while slogging through grad school. My education is in Politics (B.A.), Science, Technology, and Public Policy (M.A.), and Science and Technology Studies (need to write that Ph.D. dissertation). I currently work and blog for the Association for Computing Machinery as its Senior Public Policy Analyst.  (Disclaimer – opinions expressed here are strictly my own.)

I do agree with David’s call for clarity but I’m inclined to consider the ‘muzzle’ as a type of de facto censorship. While the research is published, as David notes, it is usually written in language that renders it inaccessible to virtually anyone who’s not an expert in that field. Reporters and other science communicators such as bloggers often act as translators of highly specialized and, at times, obscure research for a variety of audiences.

Direct access to the scientist or expert researcher allows the reporter/communicator to clarify and better understand the materials as they translate it for other audiences, particularly non expert audiences. Without direct access, the act of translation becomes highly difficult if not impossible. As a direct consequence, you have de facto censorship from every audience other than expert audiences.

Here’s the definition of censorship I found at Wikipedia,

 Censorship is the suppression of speech or other public communication which may be considered objectionable, harmful, sensitive, or inconvenient to the general body of people as determined by a government, media outlet, or other controlling body.

Given that definition and getting back to Campbell and her response to my electrochromic window questions, then it could be described as censorship if she’s withholding information (again, she did not refuse access to scientists [she contacted Alberto Cayuela for the first response], which differentiates this from the Environment Canada example). It is possible, although not likely, that the CIRS team does not have the information I requested in my follow up questions.

While I don’t like being on the receiving end, I do believe there are some situations where censorship is indicated. I’m not convinced that’s the case with the electrochromic windows at the CIRS but I am willing to entertain the possibility.

ETA March 9, 2012: Here’s a posting by Leigh Bedon (March 8, 2012) on Techdirt about the issue of the government limiting media access to scientists. The title, Canadians To Prime Minister: Don’t Censor Our Scientists, hints at Bedon’s perspective.

*’haz’ corrected to ‘haz’ on August 28, 2015.