Los Alamos National Laboratory – Stable light from ‘squashed’ Quantum Dots provide viable alternative to presently employed nanoscale light sources used in the Commercialization of quantum-dot displays, TV’s and more …


quantumdotsl
Novel colloidal quantum dots are formed of an emitting cadmium/selenium (Cd/Se) core enclosed into a compositionally graded CdxZn1-xSe shell wherein the fraction of zinc versus cadmium increases towards the dot’s periphery. Due to a …more

 

” The new colloidal processing techniques allow for preparation of virtually ideal quantum-dot emitters with nearly 100 percent emission quantum yields shown for a wide range of visible, infrared and ultraviolet wavelengths. These advances have been exploited in a variety of light-emission technologies, resulting in successful commercialization of quantum-dot displays and TV sets … “

Intentionally “squashing” colloidal quantum dots during chemical synthesis creates dots capable of stable, “blink-free” light emission that is fully comparable with the light produced by dots made with more complex processes. The squashed dots emit spectrally narrow light with a highly stable intensity and a non-fluctuating emission energy. New research at Los Alamos National Laboratory suggests that the strained colloidal quantum dots represent a viable alternative to presently employed nanoscale light sources, and they deserve exploration as single-particle, nanoscale light sources for optical “quantum” circuits, ultrasensitive sensors, and medical diagnostics.

squashed quantum dot morestableli

“In addition to exhibiting greatly improved performance over traditional produced , these new strained dots could offer unprecedented flexibility in manipulating their emission color, in combination with the unusually narrow, ‘subthermal’ linewidth,” said Victor Klimov, lead Los Alamos researcher on the project. “The squashed dots also show compatibility with virtually any substrate or embedding medium as well as various chemical and biological environments.”

The new colloidal processing techniques allow for preparation of virtually ideal quantum-dot emitters with nearly 100 percent emission quantum yields shown for a wide range of visible, infrared and ultraviolet wavelengths. These advances have been exploited in a variety of light-emission technologies, resulting in successful commercialization of quantum-dot displays and TV sets.

The next frontier is exploration of  as single-particle, nanoscale light sources. Such future “single-dot” technologies would require particles with highly stable, nonfluctuating spectral characteristics. Recently, there has been considerable progress in eliminating random variations in emission intensity by protecting a small emitting core with an especially thick outer layer. However, these thick-shell structures still exhibit strong fluctuations in emission spectra.

los alamos xlosalamoslogo.png.pagespeed.ic.w4zn0ixzm6In a new publication in the journal Nature Materials, Los Alamos researchers demonstrated that spectral fluctuations in single-dot emission can be nearly completely suppressed by applying a new method of “strain engineering.” The key in this approach is to combine in a core/shell motif two semiconductors with directionally asymmetric lattice mismatch, which results in anisotropic compression of the emitting core.

This modifies the structures of electronic states of a  dot and thereby its  emitting properties. One implication of these changes is the realization of the regime of local charge neutrality of the emitting “exciton” state, which greatly reduces its coupling to lattice vibrations and fluctuating electrostatic environment, key to suppressing fluctuations in the emitted spectrum. An additional benefit of the modified electronic structures is dramatic narrowing of the  linewidth, which becomes smaller than the room-temperature thermal energy.

 Explore further: Sandwich structure of nanocrystals as quantum light source

More information: Young-Shin Park et al, Asymmetrically strained quantum dots with non-fluctuating single-dot emission spectra and subthermal room-temperature linewidths, Nature Materials (2018). DOI: 10.1038/s41563-018-0254-7

 

Los Alamos National Laboratory Studies Perovskites for Efficient Optoelectronics: Video


Los Alamos III 13785853973_eee18af4fc_b

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are gaining an extra degree of freedom in designing and fabricating efficient optoelectronic devices based on 2D layered hybrid perovskites. Industrial applications could include low cost solar cells, LEDs, laser diodes, detectors, and other nano-optoelectronic devices.

Los Alamos Lab lanl-logo-footerThe 2D, near-single-crystalline “Ruddlesden-Popper” thin films have an out-of-plane orientation so that uninhibited charge transport occurs through the perovskite layers in planar devices. The new research finds the existence of “layer-edge-states” at the edges of the perovskite layers which are key to both high efficiency of solar cells (greater than 12 percent) and high fluorescence efficiency (a few tens of percent) for LEDs. The spontaneous conversion of excitons (bound electron-hole pairs) to free carriers via these layer-edge states appears to be the key to the improvement of the photovoltaic and light-emitting thin film layered materials.

Watch the Video

See the news release here:
http://www.lanl.gov/discover/news-rel…

And the research paper in Science:
http://science.sciencemag.org/content…

Nanotechnology Education for the Global World: Training the Leaders of Tomorrow


Nano Education 062116 nn-2016-03872b_0004

Nanoscience is one of the fastest growing and most impactful fields in global scientific research. In order to support the continued development of nanoscience and nanotechnology, it is important that nanoscience education be a top priority to accelerate research excellence. In this Nano Focus, we discuss current approaches to nanoscience training and propose a learning design framework to promote the next generation of nanoscientists. Prominent among these are the abilities to communicate and to work across and between conventional disciplines. While the United States has played leading roles in initiating these developments, the global landscape of nanoscience calls for worldwide attention to this educational need. Recent developments in emerging nanoscience nations are also discussed. Photo credit: Jae Hyeon Park.

Education has long been recognized as an important factor for growing the fields of nanoscience and nanotechnology and solidifying and expanding their roles in the global economy. In many countries, there is growing interest in developing educational programs across the full spectrum of educational levels from K-12 to postgraduate studies.

Various formal and informal educational practices are being designed and tested that promote general awareness of nanoscience and nanotechnology as well as provide advanced learning and skills development, including through group learning and peer assessment”In their article, the authors discuss innovative learning models that are being applied at the undergraduate level in order to train future leaders at the interface of engineering and management.

students running nanoscience experiments

Middle and high school students spend time at the California NanoSystems Institute at UCLA running nanoscience experiments. High school teachers from over 100 schools and 30 school districts are trained, networked to one another, and supplied with kits for their classrooms. Graduate students, postdocs, faculty, and staff run, expand, and improve these fully subscribed outreach events on a continuous basis. (© American Chemical Society)

While thee programs are not strictly focused on nanotechnology, many graduates pursue nanotechnology-focused careers and they provide examples of important factors that should be considered in the nanotechnology field.Moreover, they represent the growing trend of holistic learning, which integrates coursework across disciplines, promotes foreign experiences, and encourages industrial internships.

Here is the set of recommendations they make:

Inspire Students To Envision What Is or Could Be Possible

Possibilities include a greater focus on nanotechnology applications in courses or hands-on laboratory experiences that tie in with class concepts. Even before reaching the classroom, students should have positive views of nanoscience and the potential it holds. Successful learning practices start with capturing the imagination of students. Communicating the remarkable features of nanoscience in a simple and clear way to the mainstream public would go a long way toward achieving this goal.

Promote Role Models Who Impact Society

From an educational perspective, the tech world is a particularly good example because successful entrepreneurs such as Steve Jobs, Elon Musk, Sheryl Sandberg, and Mark Zuckerberg have captured the public audience and inspired countless students to think beyond the classroom. In nanotechnology, similar role models can inspire students with the many opportunities available in the field.

Encourage Global Collaboration

Nanotechnology research and development is truly global. Early exposure to these trends will better inform students about career opportunities and give them ideas about how to work together in teams across disciplines and cultures. A growing number of partnerships already provide international experiences for nanoscience and nanotechnology students.

Support Early Exposure Inside and Outside of the Laboratory

For many students, nanoscience and nanotechnology are about working in a lab doing scientific research. While this activity is common, its generalization could not be farther from the truth. There are many possible ways to get involved in nanotechnology, from instructional education and hands-on training to entrepreneurship and manufacturing.Holistic approaches that integrate these different possibilities, while providing targeted career development, would greatly benefit students and the overall goals of nanotechnology education. Developing a strong workforce infrastructure for nanotechnology

Communication Across Fields

Stressing the importance of communication, the authors conclude:

“Finally, one of the great strengths of the nanoscience and nanotechnology communities is that we have taught each other how to communicate across fields, to look at and to leverage each other’s approaches, and to address the key issues of a multitude of fields.

As a field, we are increasingly viewed as problem solvers in science and technology, developing new tools, materials, methods, and opportunities. Bringing this aspect of our field to students (and scientists and engineers at all levels) will have significant impact on the world around us and our ability to make it better.”

By Michael Berger. © Nanowerk

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Solar Energy – Quantum Dot Powered Windows: Los Alamos National Laboratory


Quantum Dot Window 082515 id41125A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy; It could turn any window into a daytime power source.
“In these devices, a fraction of light transmitted through the window is absorbed by nanosized particles (semiconductor quantum dots) dispersed in a glass window, re-emitted at the infrared wavelength invisible to the human eye, and wave-guided to a solar cell at the edge of the window,” said Victor Klimov, lead researcher on the project at the Department of Energy’s Los Alamos National Laboratory. “Using this design, a nearly transparent window becomes an electrical generator, one that can power your room’s air conditioner on a hot day or a heater on a cold one.”
This is what becomes possible with new devices – quantum dot LSCs –which will be available in the journal Nature Nanotechnology in the study “Highly efficient large-area colourless luminescent solar concentrators using heavy-metal-free colloidal quantum dots”. The work was performed by researchers at the Center for Advanced Solar Photophysics (CASP) of Los Alamos, led by Klimov and the research team coordinated by Sergio Brovelli and Francesco Meinardi of the Department of Materials Science of the University of Milan-Bicocca (UNIMIB) in Italy.
quantum dot window
The luminescent solar concentrator could turn any window into a daytime power source.
In April 2014, using special composite quantum dots, the American-Italian collaboration demonstrated the first example of large-area luminescent solar concentrators free from reabsorption losses of the guided light by the nanoparticles. This represented a fundamental advancement with respect to the earlier technology, which was based on organic emitters that allowed for the realization of concentrators of only a few centimeters in size.
However, the quantum dots used in previous proof-of-principle devices were still unsuitable for real-world applications, as they were based on the toxic heavy metal cadmium and were capable of absorbing only a small portion of the solar light. This resulted in limited light-harvesting efficiency and strong yellow/red coloring of the concentrators, which complicated their application in residential environments.
Klimov, CASP’s director, explained how the updated approach solves the coloring problem: “Our new devices use quantum dots of a complex composition which includes copper (Cu), indium (In), selenium (Se) and sulfur (S). This composition is often abbreviated as CISeS. Importantly, these particles do not contain any toxic metals that are typically present in previously demonstrated LSCs.”
“Furthermore,” Klimov noted, “the CISeS quantum dots provide a uniform coverage of the solar spectrum, thus adding only a neutral tint to a window without introducing any distortion to perceived colors. In addition, their near-infrared emission is invisible to a human eye, but at the same time is ideally suited for most common solar cells based on silicon.”
Francesco Meinardi, professor of Physics at UNIMIB, described the emerging work, noting, “In order for this technology to leave the research laboratories and reach its full potential in sustainable architecture, it is necessary to realize non-toxic concentrators capable of harvesting the whole solar spectrum.”
“We must still preserve the key ability to transmit the guided luminescence without reabsorption losses, though, so as to complement high photovoltaic efficiency with dimensions compatible with real windows. The aesthetic factor is also of critical importance for the desirability of an emerging technology,” Meinardi said.
Hunter McDaniel, formerly a Los Alamos CASP postdoctoral fellow and presently a quantum dot entrepreneur (UbiQD founder and president), added, “with a new class of low-cost, low-hazard quantum dots composed of CISeS, we have overcome some of the biggest roadblocks to commercial deployment of this technology.”
“One of the remaining problems to tackle is reducing cost, but already this material is significantly less expensive to manufacture than alternative quantum dots used in previous LSC demonstrations,” McDaniel said.
A key element of this work is a procedure comparable to the cell casting industrial method used for fabricating high optical quality polymer windows. It involves a new UNIMIB protocol for encapsulating quantum dots into a high-optical quality transparent polymer matrix. The polymer used in this study is a cross-linked polylaurylmethacrylate, which belongs to the family of acrylate polymers. Its long side-chains prevent agglomeration of the quantum dots and provide them with the “friendly” local environment, which is similar to that of the original colloidal suspension. This allows one to preserve light emission properties of the quantum dots upon encapsulation into the polymer.
Sergio Brovelli, the lead researcher on the Italian team, concluded: “Quantum dot solar window technology, of which we had demonstrated the feasibility just one year ago, now becomes a reality that can be transferred to the industry in the short to medium term, allowing us to convert not only rooftops, as we do now, but the whole body of urban buildings, including windows, into solar energy generators.”
“This is especially important in densely populated urban area where the rooftop surfaces are too small for collecting all the energy required for the building operations,” he said. He proposes that the team’s estimations indicate that by replacing the passive glazing of a skyscraper such as the One World Trade Center in NYC (72,000 square meters divided into 12,000 windows) with our technology, it would be possible to generate the equivalent of the energy need of over 350 apartments.
“Add to these remarkable figures, the energy that would be saved by the reduced need for air conditioning thanks to the filtering effect by the LSC, which lowers the heating of indoor spaces by sunlight, and you have a potentially game-changing technology towards “net-zero” energy cities,” Brovelli said.
Source: Los Alamos National Laboratory

Read more: Capture sunlight with your quantum dot window

Shiny Quantum Dots Brighten Future of Solar Cells


NIST 13785853973_eee18af4fc_b

Quantum dot LSC devices under ultraviolet illumination.

The project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

Photovoltaic solar-panel windows could be next for your house

LOS ALAMOS, N.M. — A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work by Los Alamos National Laboratory researchers in collaboration with scientists from University of Milano-Bicocca (UNIMIB), Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

“The key accomplishment is the demonstration of large-area luminescent solar concentrators that use a new generation of specially engineered quantum dots,” said lead researcher Victor Klimov of the Center for Advanced Solar Photophysics (CASP) at Los Alamos.

Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry.  Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology – quantum dot displays – employed, for example, in the newest generation of the Kindle Fire ™ e-reader.QDLED 08_Bulovic_QDs_inLiquidSolutions

Light-harvesting antennas

A luminescent solar concentrator (LSC) is a photon management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided towards the slab edge equipped with a solar cell.

Klimov explained, “The LSC serves as a light-harvesting antenna which concentrates solar radiation collected from a large area onto a much smaller solar cell, and this increases its power output.”

“LSCs are especially attractive because in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy generation units,” said Sergio Brovelli, who worked at Los Alamos until 2012 and is now a faculty member at UNIMIB.

Because of highly efficient, color-tunable emission and solution processability, quantum dots are attractive materials for use in inexpensive, large-area LSCs.   One challenge, however, is an overlap between emission and absorption bands in the dots, which leads to significant light losses due to the dots re-absorbing some of the light they produce.

“Giant” but still tiny, engineered dots

To overcome this problem the Los Alamos and UNIMIB researchers have developed LSCs based on quantum dots with artificially induced large separation between emission and absorption bands (called a large Stokes shift).

These “Stokes-shift” engineered quantum dots represent cadmium selenide/cadmium sulfide (CdSe/CdS) structures in which light absorption is dominated by an ultra-thick outer shell of CdS, while emission occurs from the inner core of a narrower-gap CdSe. The separation of light-absorption and light-emission functions between the two different parts of the nanostructure results in a large spectral shift of emission with respect to absorption, which greatly reduces losses to re-absorption.

To implement this concept, Los Alamos researchers created a series of thick-shell (so-called “giant”) CdSe/CdS quantum dots, which were incorporated by their Italian partners into large slabs (sized in tens of centimeters) of polymethylmethacrylate (PMMA). While being large by quantum dot standards, the active particles are still tiny – only about hundred angstroms across. For comparison, a human hair is about 500,000 angstroms wide.

“A key to the success of this project was the use of a modified industrial method of cell-casting, we developed at UNIMIB Materials Science Department” said Francesco Meinardi, professor of Physics at UNIMIB.

Spectroscopic measurements indicated virtually no losses to re-absorption on distances of tens of centimeters. Further, tests using simulated solar radiation demonstrated high photon harvesting efficiencies of approximately 10% per absorbed photon achievable in nearly transparent samples, perfectly suited for utilization as photovoltaic windows.

Despite their high transparency, the fabricated structures showed significant enhancement of solar flux with the concentration factor of more than four. These exciting results indicate that “Stokes-shift-engineered” quantum dots represent a promising materials platform. It may enable the creation of solution processable large-area LSCs with independently tunable emission and absorption spectra.

Publication: A research paper, “Large-area luminescent solar concentrators based on ‘Stokes-shift-engineered’ nanocrystals in a mass-polymerized PMMA matrix,” is published online this week in Nature Photonics.

Funding: The Center for Advanced Solar Photophyscis (CASP) is an Energy Frontier Research Center funded by the Office of Science of the US Department of Energy.

The work of the UNIMIB team was conducted within the UNIMIB Department of Materials Science and funded by Fondazione Cariplo (2012-0844) and the European Community’s Seventh Framework Programme (FP7/2007-2013; grant agreement no. 324603).

Caption for image below:  This schematic shows how the quantum dots are embedded in the plastic matrix and capture sunlight to improve solar panel efficiency.

About Los Alamos National Laboratory

Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and URS for the Department of Energy’s National Nuclear Security Administration.

Genesis Nanotech Headlines Are Out!


Organ on a chip organx250Genesis Nanotech Headlines Are Out! Read All About It!

https://paper.li/GenesisNanoTech/1354215819#!headlines

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SUBCOMMITTE EXAMINES BREAKTHROUGH NANOTECHNOLOGY OPPORTUNITIES FOR AMERICA

Chairman Terry: “Nanotech is a true science race between the nations, and we should be encouraging the transition from research breakthroughs to commercial development.”

WASHINGTON, DCThe Subcommittee on Commerce, Manufacturing, and Trade, chaired by Rep. Lee Terry (R-NE), today held a hearing on:

“Nanotechnology: Understanding How Small Solutions Drive Big Innovation.”

 

 

electron-tomography

“Great Things from Small Things!” … We Couldn’t Agree More!

 

Quantum Dots may turn House Windows into Solar Panels


 

New-QD-Solar-Cell-id35756-150x150A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work by researchers at Los Alamos National Laboratory in the US in collaboration with scientists from University of Milano-Bicocca (UNIMIB) in Italy.

Their work, published earlier this year in Nature Photonics, demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

“The key accomplishment is the demonstration of large-area luminescent solar concentrators that use a new generation of specially engineered quantum dots,” said lead researcher Victor Klimov of the Center for Advanced Solar Photophysics at Los Alamos. Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry.

A luminescent solar concentrator (LSC) is a photon-management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided toward the slab edge equipped with a solar cell.

Quantum dots are embedded in the plastic matrix and capture sunlight to improve solar-panel efficiency.
Courtesy Los Alamos Lab.
 
LUMINESCENT SOLAR CONCENTRATOR AS LIGHT HARVESTER

Sergio Brovelli, a faculty member at UNIMIB and a co-author of the paper, explained, “The LSC serves as a light-harvesting antenna which concentrates solar radiation collected from a large area onto a much smaller solar cell, and this increases its power output. LSCs are especially attractive because in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy-generation units.”

Because of highly efficient, color-tunable emission and solution processability, quantum dots are attractive materials for use in inexpensive, large-area LSCs. To overcome a nagging problem of light reabsorption, the Los Alamos and UNIMIB researchers developed LSCs based on quantum dots with artificially induced large separation between emission and absorption bands, known as a large Stokes shift.

These “Stokes-shift-engineered” quantum dots represent cadmium selenide/cadmium sulfide (CdSe/CdS) structures in which light absorption is dominated by an ultra-thick outer shell of CdS, while emission occurs from the inner core of a narrower-gap CdSe.

Los Alamos researchers created a series of thick-shell (so-called “giant”) CdSe/CdS quantum dots, which were incorporated by their Italian partners into large slabs (sized in tens of centimeters across) of polymethylmethacrylate. While being large by quantum dot standards, the active particles are still tiny, only about hundred angstroms across.

QUANTUM DOTS USED FOR NEW DISPLAYS

Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry.

Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100%.3D Printing dots-2

These properties have recently become the basis of a new technology — quantum-dot displays — employed, for example, in the newest generation of the Kindle Fire e-reader.

In a new SPIE.TV video, Lawrence Berkeley National Lab director Paul Alivisatos demonstrates the Kindle Fire quantum-dot display.

 

DOI: 10.1117/2.4201407.10

Subcommittee Examines Breakthrough Nanotechnology Opportunities for America


Applications-of-Nanomaterials-Chart-Picture1SUBCOMMITTE EXAMINES BREAKTHROUGH NANOTECHNOLOGY OPPORTUNITIES FOR AMERICA
July 29, 2014

WASHINGTON, DCThe Subcommittee on Commerce, Manufacturing, and Trade, chaired by Rep. Lee Terry (R-NE), today held a hearing on “Nanotechnology: Understanding How Small Solutions Drive Big Innovation.” Nanotechnology is science, engineering, and technology conducted at the nanoscale, which is approximately 1 to 100 nanometers (one nanometer is a billionth of a meter). This technology brings great opportunities to advance a broad range of industries, bolster our U.S. economy, and create new manufacturing jobs. Members heard from several nanotech industry leaders about the current state of nanotechnology and the direction that it is headed.UNIVERSITY OF WATERLOO - New $5 million lab

“Just as electricity, telecommunications, and the combustion engine fundamentally altered American economics in the ‘second industrial revolution,’ nanotechnology is poised to drive the next surge of economic growth across all sectors,” said Chairman Terry.

 

 

Applications of Nanomaterials Chart Picture1

Dr. Christian Binek, Associate Professor at the University of Nebraska-Lincoln, explained the potential of nanotechnology to transform a range of industries, stating, “Virtually all of the national and global challenges can at least in part be addressed by advances in nanotechnology. Although the boundary between science and fiction is blurry, it appears reasonable to predict that the transformative power of nanotechnology can rival the industrial revolution. Nanotechnology is expected to make major contributions in fields such as; information technology, medical applications, energy, water supply with strong correlation to the energy problem, smart materials, and manufacturing. It is perhaps one of the major transformative powers of nanotechnology that many of these traditionally separated fields will merge.”

Dr. James M. Tour at the Smalley Institute for Nanoscale Science and Technology at Rice University encouraged steps to help the U.S better compete with markets abroad. “The situation has become untenable. Not only are our best and brightest international students returning to their home countries upon graduation, taking our advanced technology expertise with them, but our top professors also are moving abroad in order to keep their programs funded,” said Tour. “This is an issue for Congress to explore further, working with industry, tax experts, and universities to design an effective incentive structure that will increase industry support for research and development – especially as it relates to nanotechnology. This is a win-win for all parties.”

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Professor Milan Mrksich of Northwestern University discussed the economic opportunities of nanotechnology, and obstacles to realizing these benefits. He explained, “Nanotechnology is a broad-based field that, unlike traditional disciplines, engages the entire scientific and engineering enterprise and that promises new technologies across these fields. … Current challenges to realizing the broader economic promise of the nanotechnology industry include the development of strategies to ensure the continued investment in fundamental research, to increase the fraction of these discoveries that are translated to technology companies, to have effective regulations on nanomaterials, to efficiently process and protect intellectual property to ensure that within the global landscape, the United States remains the leader in realizing the economic benefits of the nanotechnology industry.”

James Phillips, Chairman & CEO at NanoMech, Inc., added, “It’s time for America to lead. … We must capitalize immediately on our great University system, our National Labs, and tremendous agencies like the National Science Foundation, to be sure this unique and best in class innovation ecosystem, is organized in a way that promotes nanotechnology, tech transfer and commercialization in dramatic and laser focused ways so that we capture the best ideas into patents quickly, that are easily transferred into our capitalistic economy so that our nation’s best ideas and inventions are never left stranded, but instead accelerated to market at the speed of innovation so that we build good jobs and improve the quality of life and security for our citizens faster and better than any other country on our planet.”

Chairman Terry concluded, “Nanotech is a true science race between the nations, and we should be encouraging the transition from research breakthroughs to commercial development. I believe the U.S. should excel in this area.”

– See more at: http://energycommerce.house.gov/press-release/subcommittee-examines-breakthrough-nanotechnology-opportunities-america#sthash.YnSzFU10.dpuf

NANOTECHNOLOGY – On the Horizon and in the Far Future: Video


 

 

 

What is Nanotechnology?

 
A basic definition: Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced.

 

 
In its original sense, ‘nanotechnology’ refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.

Nanotechnology (sometimes shortened to “nanotech”) is the manipulation of matter on an atomic and molecular scale. The earliest, widespread description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology.

A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter that occur below the given size threshold.

It is therefore common to see the plural form “nanotechnologies” as well as “nanoscale technologies” to refer to the broad range of research and applications whose common trait is size. Because of the variety of potential applications (including industrial and military), governments have invested billions of dollars in nanotechnology research.

Through its National Nanotechnology Initiative, the USA has invested 3.7 billion dollars. The European Union has invested 1.2 billion and Japan 750 million dollars

Embedded Quantum Dots Brighten the Future of Solar Cells


Los Anamos QD 13786149104_3291f6c66a_bA house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work by Los Alamos National Laboratory researchers in collaboration with scientists from University of Milano-Bicocca (UNIMIB), Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

“The key accomplishment is the demonstration of large-area luminescent solar concentrators that use a new generation of specially engineered quantum dots,” said lead researcher Victor Klimov of the Center for Advanced Solar Photophysics (CASP) at Los Alamos.

This schematic shows how the quantum dots are embedded in the plastic matrix and capture sunlight to improve solar panel efficiency.

Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry. Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology – quantum dot displays – employed, for example, in the newest generation of the Kindle Fire ™ e-reader.

Light-harvesting antennas

A luminescent solar concentrator (LSC) is a photon management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided towards the slab edge equipped with a solar cell.

Klimov explained, “The LSC serves as a light-harvesting antenna which concentrates solar radiation collected from a large area onto a much smaller solar cell, and this increases its power output.” “LSCs are especially attractive because in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy generation units,” said Sergio Brovelli, who worked at Los Alamos until 2012 and is now a faculty member at UNIMIB.

Because of highly efficient, color-tunable emission and solution processability, quantum dots are attractive materials for use in inexpensive, large-area LSCs. One challenge, however, is an overlap between emission and absorption bands in the dots, which leads to significant light losses due to the dots re-absorbing some of the light they produce.

“Giant” but still tiny, engineered dots

To overcome this problem the Los Alamos and UNIMIB researchers have developed LSCs based on quantum dots with artificially induced large separation between emission and absorption bands (called a large Stokes shift).

These “Stokes-shift” engineered quantum dots represent cadmium selenide/cadmium sulfide (CdSe/CdS) structures in which light absorption is dominated by an ultra-thick outer shell of CdS, while emission occurs from the inner core of a narrower-gap CdSe. The separation of light-absorption and light-emission functions between the two different parts of the nanostructure results in a large spectral shift of emission with respect to absorption, which greatly reduces losses to re-absorption.

To implement this concept, Los Alamos researchers created a series of thick-shell (so-called “giant”) CdSe/CdS quantum dots, which were incorporated by their Italian partners into large slabs (sized in tens of centimeters) of polymethylmethacrylate (PMMA). While being large by quantum dot standards, the active particles are still tiny – only about hundred angstroms across. For comparison, a human hair is about 500,000 angstroms wide.

“A key to the success of this project was the use of a modified industrial method of cell-casting, we developed at UNIMIB Materials Science Department” said Francesco Meinardi, professor of Physics at UNIMIB.

Spectroscopic measurements indicated virtually no losses to re-absorption on distances of tens of centimeters. Further, tests using simulated solar radiation demonstrated high photon harvesting efficiencies of approximately 10% per absorbed photon achievable in nearly transparent samples, perfectly suited for utilization as photovoltaic windows.

Despite their high transparency, the fabricated structures showed significant enhancement of solar flux with the concentration factor of more than four. These exciting results indicate that “Stokes-shift-engineered” quantum dots represent a promising materials platform. It may enable the creation of solution processable large-area LSCs with independently tunable emission and absorption spectra.


Publication: A research paper, “Large-area luminescent solar concentrators based on ‘Stokes-shift-engineered’ nanocrystals in a mass-polymerized PMMA matrix,” is published online this week in Nature Photonics.


Source: Los Alamos National Laboratory