Tetrapod Nanocrystals as Fluorescent Stress Probes of Electrospun Nanocomposites

Abstract Image



A nanoscale, visible-light, self-sensing stress probe would be highly desirable in a variety of biological, imaging, and materials engineering applications, especially a device that does not alter the mechanical properties of the material it seeks to probe. Here we present the CdSe–CdS tetrapod quantum dot, incorporated into polymer matrices via electrospinning, as an in situ luminescent stress probe for the mechanical properties of polymer fibers. The mechanooptical sensing performance is enhanced with increasing nanocrystal concentration while causing minimal change in the mechanical properties even up to 20 wt % incorporation. The tetrapod nanoprobe is elastic and recoverable and undergoes no permanent change in sensing ability even upon many cycles of loading to failure. Direct comparisons to side-by-side traditional mechanical tests further validate the tetrapod as a luminescent stress probe. The tetrapod fluorescence stress–strain curve shape matches well with uniaxial stress–strain curves measured mechanically at all filler concentrations reported.

Tetrapod Quantum Dots Break Kasha’s Rule: Enhanced Performance Enables Commercialization

QDOTS imagesCAKXSY1K 8SAN MARCOS, Texas, June 6, 2013 /PRNewswire/ — By Quantum Materials Corporation (OTCQB:QTMM) – Since 1950,  Kasha’s  Rule 1, a principle of photochemistry,  held true  that if a source of light excited a molecule enough, the molecule would  fluoresce in a single color.


In 2011, the Alivasatos group at DOE’s  Lawrence Berkeley National Laboratory, using tetrapod quantum dots, broke  Kasha’s rule2 by causing them to emit two separate colors instead of  just one. This dual emission is possible because the tetrapod’s core and arms  can separately emit at different wavelengths, and this discovery finds potential  in many new advances in optics and nano-bio applications.

Quantum Materials Corp. (QMC) is delivering tetrapod quantum dots to a client studying dual emission  effects in sensitive force sensing environments. Dual-emitting tetrapod QD  sensors can measure very minute stresses such as those of a heartbeat by reading  the changing variance of luminescence response emitted as the tetrapod quantum  dots arms bend. Nano-probes of this type are poised to be a platform technology  providing optical readout for many other biomechanical processes.  This  unique ability of the tetrapod quantum dot helps it to outshine the more common  spherically shaped quantum dot.

QMC’s patented synthesis allows precise control of tetrapod quantum dot  composition, size of QD core, length of arms, and arm thickness. This ability to  design the tetrapod characteristics allows optimization to control the  tetrapod’s reaction to stress and thereby tune the light emissions for different  applications. QMC VP of R&D David Doderer remarked, “We are proud  to  stand out as the singular company that can provide industrial-scale quantities  of tetrapod quantum dots, customized to our client’s needs, with the uniformity  and reliability necessary to feed the demands of large scale commercial  operations.”

Quantum Materials Corporation has established new offices at STAR Park in San Marcos.  QMC C.E.O. is enthusiastic  about the move, quote “The facilities are state-of-the-art and Texas State faculty and the STAR Park Leadership continue to offer us  opportunities to discuss collaborative projects from a well-connected home base.  Indeed, so soon after coming to STAR Park, we  are already determining scheduled visits from global companies that have  indicated strong interest in discussing business opportunities.”

While currently marketing our tetrapod quantum dot technology to end users in  the Printed Electronic, LED, and Solar markets, QMC is specifically focusing  efforts on capturing a significant market share of the 2013 forecast estimated  over $100MM by BCC Research for quantum dots in Bioscience applications. To  accomplish this, QMC will demonstrate our tetrapod quantum dots’ superiority  over standard spherical quantum dots to our diverse customer base.

MarketsandMarkets 2012 Quantum Dot Global Forecast predicts total QD  sales of $7.48 Billion by 2022 in a wide range of  QD applications.

  1. http://en.wikipedia.org/wiki/Kasha’s_rule
  2. http://www.sciencedaily.com/releases/2011/07/110701150459.htm

About Quantum Materials Corporation

QUANTUM MATERIALS CORPORATION, INC has a steadfast vision that  advanced technology is the solution to global issues related to cost, efficiency  and increasing energy usage. Quantum dot semiconductors enable a new level of  performance in a wide array of established consumer and industrial products,  including low power lighting and displays and biomedical diagnostic  applications. QMC’s volume manufacturing methods enables cost reductions moving  laboratory discovery to commercialization


Got Quantum Dots? Seeking to Impact Our Lives (for the better) through Nanotechnology

QDOTS imagesCAKXSY1K 8 Got Quantum Dots?


A Nanotechnology and Applied Materials company, Quantum Materials Corporation (QMC), explains that Quantum dots refer to one of several promising materials niche sectors that recently have emerged from tremendous nanotechnology advances in chemistry and materials processing in the past two decades, and fall into the category of nano-crystals, which also includes quantum rods and nanowires. QMC believes there are abundant opportunities  to commercialize the many applications emerging now in this arena … and QMC intends to capitalize on those opportunities! (See potential Applications Below)

As a materials subset, quantum dots are characterized by synthetic nano-materials particles fabricated to the smallest of dimensions from only a few atoms and upwards. At these tiny dimensions, they behave according to the rules of quantum physics, which describe the behavior of atoms and sub atomic particles, in contrast to classical physics that describes the behavior of bulk materials. In other words, objects consisting of many atoms.

Quantum Dots measure near one billionth of an inch and are a non-traditional type of semiconductor that can be used as an enabling material across many industries that is unparalleled in versatility and flexible in form.

Quantum Materials Corporation (QMC) is now commercializing a low cost quantum dot technology of a superior quality and characteristics. This revolutionary new quantum dot production technique, developed by Dr. Michael S. Wong and colleagues at Houston’s William Marsh Rice University, has been acquired under an exclusive, world-wide license. QMC’s new synthesis method is mass producible using continuous flow technology processes developed in conjunction with Access2Flow micro-reactor technology. QMC’s research and development group was instrumental in developing the new scaling-up process.

michaelwongRice University Quantum Dot Synthesis

Dr. Wong’s Rice University lab invented a simplified synthesis using greener fluids in a moderate temperature process producing same-sized QD particles, in which more than 95 percent are tetrapods; where previously even in the best recipe less than 50 percent of the prepared particles were all same size and tetrapods. These highly efficient tetrapod QD are available across the entire light wavelength from UV to IR spectra and very narrow bandwidth is common. Selectivity of arm width and length is very high allowing different characteristics to be emphasized. Capping with shells and dyes adds desired properties. A custom mixture of quantum dots tuned to optimal wavelengths is easy to create, and projects will have the advantage of unprecedented flexibility and quantities for determining the optimal quantum dot without the time, expense and poor quality of batch synthesis methods.

Moreover, the Rice process uses much cheaper raw materials and fewer purification steps. A positively charged molecule called cetyltrimethylammonium bromide provides this dramatic improvement in tetrapod manufacture. This compound, found in some shampoos, also is 100 times cheaper than alkylphosphonic acids currently used and is far safer, further simplifying the manufacturing process.

With the underlying theme of designing and engineering novel materials for catalytic and encapsulation applications, Dr. Wong’s research interests lie in the areas of nanostructured materials (e.g. nanoporous materials, nanoparticle-based hollow spheres, and quantum dots), heterogeneous catalysis, and bioengineering applications. He is particularly interested in developing new chemical approaches to assembling nanoparticles into functional macrostructures.

QD Nanotech Applications

Current and future applications of quantum dots impact a broad range of industrial markets. These include, for example, biology and biomedicine; computing and memory; electronics and displays; optoelectronic devices such as LEDs, lighting, and lasers; optical components used in telecommunications; and security applications such as covert identification tagging or biowarfare detection sensors. All of these markets can move from laboratory discovery to commercialization as QMC scales production of quantum dots to robust levels. They include:

IN VITRO analysis for cells and biological systems:

Quantum dots make improvements in the quality of marking in both brightness and time to study (hours instead of minutes).

IN VIVO selective tissue marking:

Quantum dots have been used for lymph node mapping and vascular and deep tissue imaging. This use has the potential to be much more significant for disease control and cure than any other current pharmacological technology.

QD Printing Applications

Quantum Materials Corporation has the exclusive worldwide license to proprietary quantum dot printing technologies developed by Dr. Ghassan Jabbour. This pioneering technology makes significant improvements over prior art.


Quantum Dot LED as well as nanoparticle LED/OLED based displays now have the potential to be manufactured using very high volume, low cost roll-to-roll print processing on inexpensive substrates, with potential to deliver a significantly lower price point combined with higher definition, increased viewing angles, lower power consumption, and reduced response time for enhanced display imaging in a very thin, light weight, format.


Tetrapod quantum dots and printing technologies can be printed and applied to certain lighting applications delivering high brightness, true color balance, long life and low energy consumption for highest efficiency. As global consumption of electricity in the world increases dramatically, energy efficiency through better electronics and lighting is a key to reducing the overall burden on power production and the expected increases in greenhouse gas emissions.


Thermoelectric devices are notoriously inefficient, and many researchers are working diligently on nanocomposite materials, such as quantum dots that artificially induce phonon scattering, thereby inhibiting heat transfer due to lattice vibrations while facilitating electron and hole conduction.

Photonics & Telecommunications:

Quantum dots open potential to develop optical switches, modulators, and other devices that rely upon nonlinear optics, with the aim of creating faster, cheaper, and more powerful optical telecommunication components.

Security Inks:

Inks and paints incorporating quantum dots, nanoscale semiconductor particles, can be tuned to emit light at specific wavelengths in the visible and infrared portion of the spectra.

While currently marketing its tetrapod quantum dot technology to end users in the Printed Electronic, LED, and Solar markets, QMC is specifically focusing efforts on capturing a significant market share of the 2013 forecast estimated over $100MM by BCC Research for quantum dots in Bioscience applications. To accomplish this, QMC says it will demonstrate its tetrapod quantum dots’ superiority over standard spherical quantum dots to its diverse customer base.

MarketsandMarkets 2012 Quantum Dot Global Forecast predicts total QD sales of $7.48 Billion by 2022 in a wide range of QD applications. Quantum Materials believes that its provision of an accessible supply of quantum dots enables potential partners to now strategically develop commercially viable quantum dot products.

A company, Quantum Materials Corporation, is delivering tetrapod quantum dots to a client studying dual emission effects in sensitive force sensing environments. Dual-emitting tetrapod QD sensors can measure very minute stresses such as those of a heartbeat by reading the changing variance of luminescence response emitted as the tetrapod quantum dots arms bend. Nano-probes of this type are poised to be a platform technology providing optical readout for many other biomechanical processes.

This unique ability of the tetrapod quantum dot helps it to outshine the more common spherically shaped quantum dot.

QMC says in a release that its patented synthesis allows precise control of tetrapod quantum dot composition, size of QD core, length of arms, and arm thickness, and this ability to design the tetrapod characteristics allows optimization to control the tetrapod’s reaction to stress and thereby tune the light emissions for different applications.

QMC with its Patented Technologies receiving the prestigious Frost and Sullivan Award “Best Practices Award” for Advanced Quantum Dot Manufacturing Enabling Technology”, is the singular company that can provide industrial-scale quantities of tetrapod quantum dots, customized client’s needs, with the uniformity and reliability necessary to feed the demands of large scale commercial operations.

Collaboration with Texas State’s Material Science, Engineering and Commercialization Doctoral Program exemplifies that institution’s powerful commitment to advancing nanotechnology “Research with Relevance” and parallels Quantum Materials’ own strategy to convert advanced quantum dot research into successful products. Texas State is creating a team environment for innovation by attracting internationally renowned faculty, encouraging cross-pollination across different scientific disciplines, and supporting STAR Park’s growth environment.

“Quantum Materials is a great example of the kind of collaborative effort Texas State University is interested in creating through STAR Park. The firm will have access to experienced faculty and specialized facilities that will support joint R&D efforts.



Adoption by TV makers Expands Market for light-emitting nanocrystals. (Quantum Dot’s)

QDOTS imagesCAKXSY1K 8Quantum Dots Go on Display




Sony has announced that it will embed quantum dots in its latest flat-screen televisions.

Steve Marcus/REUTERS

Sony Announces Use of QD's in TV Screens

Live from your living room, in super­saturated colour: it’s the quantum-dot TV! Researchers working with nanoscale fluorescent particles called quantum dots have long predicted groundbreaking achievements, such as ultra-efficient light-emitting diodes (LEDs) and solar cells, but the technology has found mainly niche applications. That could change with the announcement last week that QD Vision, based in Lexington, Massachusetts, would supply Sony Corporation of Tokyo with quantum dots for flat-screen televisions that will transmit more richly coloured images than other TVs on the market.

Demand for quantum-dot displays, say industry watchers, could benefit quantum-dot companies, bring down the price of these nanomaterials and boost other applications that have stalled. “Displays are a potential market that could help quantum-dot companies find traction,” says Jonathan Melnick, an analyst at Lux Research in Boston, Massachusetts.

Quantum dots are crystals about 10 nano­metres in diameter, made from a semiconductor material, commonly cadmium selenide. They are so tiny that their shape and size affect the quantum properties of their electrons, in particular their energy gap — the energy needed to kick electrons into a higher-energy band — which determines the colour of light that the mater­ial can emit. Whereas a bulk semiconductor is limited to emitting a single colour of light, researchers can tune the precise colour a quantum dot will absorb and re-emit by tailoring its size.

Discovered in 1981, quantum dots did not find applications until 2002. That was when the Quantum Dot Corporation of Hayward, California, began selling them to cell biologists, who prize them as fluorescent imaging labels for proteins and other biological molecules. As recently as 2010, the biomedical sector was responsible for US$48 million of $67 million in total quantum-dot revenues, according to BCC Research of Wellesley, Massachusetts.

Quantum dots have shown promise for electronics, too — for example in solar cells, in which a mix of quantum dots tuned to absorb different wavelengths of light could capture more of the energy in the solar spectrum. But one hurdle to their exploitation was their temperature sensitivity. Near the backlight of a liquid-crystal display (LCD), for example, temperatures can be around 100 °C. At this temperature, the dots lose efficiency and up to half of their brightness, says QD Vision co-founder and chief technology officer Seth Coe-Sullivan. He says that the company spent a long time tuning the chemistry of its quantum dots to make them stable at higher temperatures.

Moungi Bawendi, a chemist at the Massachusetts Institute of Technology in Cambridge and a co-founder of QD Vision, admits that the company also made some business miscalculations. For its first product, in 2009, it provided Nexxus Lighting of Charlotte, North Carolina, with quantum-dot coatings to convert the harsh glare of LEDs into a warmer glow, to make them more appealing as long-life, low-energy light bulbs. But Bawendi says that LED designs and technology for the light-bulb market evolved too fast for the quantum-dot coatings to keep up. “You design something, and six months later it doesn’t work,” Bawendi says. “Television technology is more stable.”

His optimism will be tested this spring with the company’s quantum-dot debut in Sony LCD televisions, to be sold under the Tri­luminos brand name. The contrast with today’s flat screens begins with the light source. Conventional LCDs use a high-intensity blue LED backlight whose glow is converted by a phosphor coating to create a broadband, white light used to make the moving TV images. The new Triluminos tele­visions instead pair an uncoated blue LED with a thin glass tube filled with quantum dots. Two kinds of quantum dots in the tube absorb some of the blue light from the backlight and re-emit it as pure red andgreen light. The resulting white light is more intense at the wavelengths of these three specific colours than the white light made by a phosphor-coated LED, so that more colour comes through in the images.

Another quantum-dot company, Nanosys of Palo Alto, California, is providing 3M of St Paul, Minnesota, with material for a similar product. 3M will make a polymer film seeded with quantum dots that does the same jobas QD Vision’s glass tube. The film is layered between the LCD’s stack of light filters, diffusers and polarizers, and similarly converts raw blue light into white light made up of pure colours. Nanosys and 3M announced their partnership in June 2012, but have not yet named any customers.

BCC predicts that, by 2015, optoelectronics, including display components, will make up $310 million of a total $666 million in quantum-dot revenues. Melnick says that these numbers might be overly optimistic, because quantum dots remain expensive. “Even on the low end, they still cost in the hundreds of dollars per gram, and range up to $10,000 per gram,” he says. But demand from 3M and Sony could help to bring prices down. Although neither QD Vision nor Nanosys would comment on the volume of material they expect to make this year, or their selling price, both say that they are scaling up their manufacturing volume.

Bawendi is not surprised that it took quantum dots so long to find their footing. “You could argue that 30 years is about the right amount of time from fundamental discovery to applications,” he says.

Quantum Dot Mass Production Breakthrough Achieved

PRNewswire/ — An Advanced Materials emerging Nanotechnology company has announced a new microreactor and software controlled continuous flow process has been successfully developed and operated for delivery of mass produced quantum dots. This new quantum dot production process replaces batch synthesis and has potential for high improvement in both yield and conversion. Tetrapod Quantum Dots are used in a variety of emerging applications including solid state lighting, QLED displays, nanobio applications and for 3rd Generation solar cells in solar panels. QD-Tetrapods have proven to have superior performance characteristics surpassing spherical nanoparticles in a number of nano-applications including Nano-Bio (delivery) and Nano-Solar (increased harvesting and efficiencies).

The inherent design of the microreactor allows for commercial-scale 0f parallel modules to achieve large production rates in a regulated, optimized system. This breakthrough production process enables both the low cost, high volume production of quantum dots, and also provides flexibility in the choice of materials used to produce the quantum dots including heavy metal free (Cadmium Free) quantum dots and other biologically inert materials.

Quantum dots have been widely recognized for their potential in next generation display technologies, solar cells, LEDs, OLEDs, computer memory, printed electronics and a vast array of security, biomedical and energy storage applications. According to research group BCC Research, the 2010 global market for quantum dots was estimated $67 million in revenues, and is projected to grow quickly over the next 5 years at greater than 50% per year reaching almost $670 million by 2015. The nanomaterials enabled market grew to $263 billion USD in 2012.

For the first time this technology offers to manufacturers that it is now realistic to test the advantages of quantum dots to establish higher performance benchmarks across a number of industries and product applications. Many discoveries and commercial applications have been developmentally slowed by the lack of high quality and consistent quantum dots. Correspondingly high costs, have also proved to be a barrier to entry and development of otherwise commercially poised nanomaterials enabled applications. This technology removes the roadblock from widespread adoption of the quantum dot as a basic building block of technology and services much like the silicon chip that has ubiquitously advanced corporate function and consumer lifestyles worldwide.

“Our goal from the onset has been to achieve a production rate of 100kg per day with a 95% or greater yield,” according to the Founder and CEO. He added that “with this breakthrough we have coupled two disruptive technologies resulting in the potential to now achieve that goal.”

According to the company’s internationally recognized CTO,  “Besides the scalability indicated, in my opinion, the truly remarkable accomplishment in this breakthrough is its adaptability to other inorganic metals and elements, including cadmium-free Quantum Dots.”

The Company has a steadfast vision that advanced technology is the solution to global issues related to cost, efficiency and increasing energy usage. Quantum dot semiconductors enable a new level of performance in a wide array of established consumer and industrial products, including low cost flexible solar cells, low power lighting and displays and biomedical research applications.

The Company intends to invigorate these markets through cost reduction and moving laboratory discovery to commercialization with volume manufacturing methods to establish a growing line of innovative high performance products.

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