Mention quantum dots to most non-scientists, and you’re likely to elicit a blank stare. It’s a term that hasn’t registered in the popular vernacular — yet. However, that could change in the not-too-distant future.
Quantum dots — a category of man-made molecules — are one of several promising materials that have recently emerged from the burgeoning growth area of nanotechnology, and fall into the category of nanocrystals, which also includes quantum rods and nanowires.
As a materials subset, quantum dots are characterized by particles fabricated to the smallest of dimensions from only a few atoms and upwards. These minuscule (2nm-10nm) man-made molecules are nanocrystal semiconductors made of materials small enough to display quantum mechanical properties are still flying pretty much under the radar of popular perception. At these tiny dimensions, quantum dots 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, or in other words, objects consisting of many atoms.
However, because quantum dots can be used as an enabling material across many industries, and are claimed to be unparalleled in versatility and flexible in form, they are projected to soon revolutionize production of transistors, solar cells, LEDs,and diode lasers, which should raise their popular profile immensely . Quantum dots (QD) are also being researched as agents for medical imaging and as possible (quantum bits – is a unit of quantum information in quantum computing).
“The Quantum Dot Century”
Texas-based nanotech firm Quantum Materials Corporation (QMC) maintains that this will be the “Quantum Dot Century,” and that kilogram quantity mass production of quantum dots will be a game-changer, with high quality and lower-priced quantum dots accelerating the rate of technological change — new products cascading into the marketplace as manufacturers learn to integrate higher efficiency/luminescence quantum dots into their products. QMC predicts that this level of change represents a new paradigm that will create new industries, products, and jobs in science and industry — and that the list of possible quantum dot applications constantly expanding.
Consequently, QMC’s management considers the projection that quantum dots mass production and economical market availability are still five to ten years in the future is simply wrong. The company’s strategy is to use its strengths in quantum dot synthesis and mass production, along with quantum dot printing abilities, to create new product paradigms in industrial and commercial applications. The company is using two proprietary disruptive technologies — a novel QD synthesis method licensed from Houston’s Rice University, and industrial scale production of QD using advanced flow chemistry micro reactor technology — to produce highly desirable tetrapod quantum dot variants at a cost saving of greater than 75% compared to competing suppliers.
Tetrapod (4 arms) shaped QD outperform all other QD shapes due to their better abilities in charge transport and multiple exciton generation (MEG). QMC coordinates with JV partners to create the optimal QD for their purpose and can choose hybrid metals and elements in various shapes and sizes. This advantage will result in specific nanocrystals for their best function and cut development time considerably. Research has shown that in a traditional solar cell each photon of light striking the cell yields one exciton.
However, pioneering work by Dr. Nozik and NREL in Golden, Colorado has demonstrated that the absorption of a single photon by their quantum dots yielded – not one exciton as is usually the case, but three of them. When a photon strikes a quantum dot it can produce potentially 3 electrons, and some reports of up to 7 electrons have been published. The formation of multiple excitons per absorbed photon happens when the energy of the photon absorbed is far greater than the semiconductor band gap. This phenomenon does not readily occur in bulk semiconductors where the excess energy simply dissipates away as heat before it can cause other electron-hole pairs to form. In semi-conducting quantum dots, the rate of energy dissipation is significantly reduced, and the charge carriers are confined within a minute volume, thereby increasing their interactions and enhancing the probability for multiple excitons to form.
“Quantum Materials is excited to be offering highly uniform Tetrapod Quantum Dots to a wide array of industry connections that have recently been established,” says QMC Vice President for Research and Development David Doderer</a> “Our research shows that Tetrapod Quantum Dots exhibit a unique potential to better the performance of the ‘industry standard’ spherical quantum dots. I believe that our inherent process improvements will result in higher uniformity and less defects in the near future, and will enable tailored solutions for many device applications. High material performance, combined with our ability to soon provide the industry with the commercial production they need, should well meet the increased demand for Tetrapod Quantum Dot products.”
The QD synthesis process has several advantages over traditional batch synthesis, including larger production amounts, which can be ) scaled up by mass production. The process allows record 95 percent conversion (full shape), uniformity (same size), and selectivity (precise control of width and length of tetrapod arms). This mastery of the QD production method distinguishes QMC from its competition.
Because electrons in Quantum Dot nano particles are confined in all three spatial dimensions, they display unique optical, electrical, and mechanical characteristics, making them an attractive option for manufacturing next-generation devices in the lighting, display, solar energy, and healthcare categories.
Interested in learning more about Quantum Materials Corporation’s tetrapod quantum dots? Be sure to read their technology section here.
QMC’s Colloidal Synthesis Method Overcomes Challenges
Although QDs were first developed for applications in the healthcare industry, research and development efforts have extended application into other fields such as sensors and flexible displays. However, challenges, such as high manufacturing cost and low performance efficiency have thus far limited adoption of QDs in most of the mentioned applications. Consequently, the low toxicity of QDs manufactured using colloidal synthesis has become the most adopted method for QD manufacturing in preference over other processes.
Colloidal synthesis is a wet chemistry method that enables manufacturing of QDs in batches. However, challenges such as expensive manufacturing equipment and low yield have increased the current manufacturing cost of QDs, thus limiting their adoption in price-sensitive sectors, such as consumer electronics.
Quantum Materials Corporation recently relocated its tetrapod quantum dot laboratories to the STAR Park (Science, Technology and Academic Research Park) at San Marcos, an Austin, Texas, suburb. The company recently also entered into a memorandum of understanding and University–Industry Partnership Agreement with Texas State University (TSU) at San Marcos, located a short distance from QMC’s new STAR Park headquarters.
The company is now commercializing a low cost quantum dot technology using a revolutionary new production technique developed by QMC board member and Professor of Chemical and Biomolecular Engineering and Chemistry Dr. Michael S. Wong and colleagues at Rice University in Houston. QMC has acquired an exclusive, worldwide license for this new synthesis method, which is mass producible using continuous flow technology processes developed in conjunction with a leading continuous flow microreactor technology. QMC’s research and development group was instrumental in devising the new scaling-up process.
“The establishment of a new laboratory facility for research, development and initial production in Texas allows us to provide manufacturing clients Tetrapod Quantum Dots specifically characterized for their unique applications,” says QMC Founder, President and CEO Stephen B. Squires. “We are working to secure funding to expand production capacity to volume quantities of Tetrapod Quantum Dots, while continuing to work with the increasing number of different industry sector leaders who have requested optimized Tetrapod Quantum Dot samples.”
Dr. Wong’s lab at Rice invented a simplified synthesis using greener fluids in a moderate temperature process producing same-sized QD particles, of 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 QDs 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 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.
Quantum Materials manufactures both Cadmium-based and Non-Heavy-Metal (Cadmium-Free) Tetrapod Quantum Dots. Colloidal Tetrapod QD are tetrahedrally symmetric nano crystals with wurtzite arms exhibiting bright and narrow emission, uniquely capable of dual emissions from one energy source and also singularly unique as micromechanical stress gauges measurable by color shifting of their energy gap when bending under strain.
To read research related to Quantum Materials Corporation, be sure to visit their Research Page here.
QMC’s patented synthesis technique 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’s David Doderer notes: “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.”
QMC’s dot semiconductors enable a new level of engineered performance in a wide array of established consumer and industrial products. The company’s volume manufacturing methods enable consistent QD quality and scalable cost reductions to drive innovative discovery to commercial success. 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.
QMC’s continuous flow microreactors manufacture the highly desirable CdSe tetrapod quantum dots at a small fraction of the cost compared to competing suppliers. Being able to supply large scale quantities with superior characteristics is a ‘disruptive game changer’ enabling quantum dot projects ready for commercialization to be brought to fruition today — years earlier than was thought possible. QMC Tetrapod quantum dots address a tremendous need in a variety of industries including semiconductor electronics, printed electronics, and medical diagnostic and biomedical applications. While QMC expects CdSe tetrapods to be its flagship product, its corporate technologies are capable of producing a range of other inorganic hybrid tetrapods and other shapes for specific purposes in niche industries and to third party developers of quantum dot products.
QMC are implementing one or more company-owned mass production lines with the design of each pilot line to scale from the initial kilogram+ output of the line at least by an order of magnitude to 100 kilograms per day per microreactor. To put this in perspective, less than one month’s quantum dot production at 100kg/day would equal the display industry’s total consumption of quantum dots in 2010. The production lines can be replicated as necessary to increase output capacity as needed.
“Quantum Materials is excited to be offering highly uniform Tetrapod Quantum Dots to a wide array of industry connections that have recently been established,” comments Mr. Doderer “Our research shows that Tetrapod Quantum Dots exhibit a unique potential to better the performance of the ‘industry standard’ spherical quantum dots. I believe that our inherent process improvements will result in higher uniformity and less defects in the near future, and will enable tailored solutions for many device applications. High material performance, combined with our ability to soon provide the industry with the commercial production they need, should well meet the increased demand for Tetrapod Quantum Dot products.”
With the list of possible quantum dot applications ever-expanding, the company envisions creative new applications waiting for the availability of quantum dots, creating a multitude of new jobs made possible by QD. They foresee applications that will create or save energy, diagnose, treat and cure formidable diseases and are Green because QPS’s quantum dot solar cell manufacture is the cleanest way to create energy (LCOE basis) and their quantum dot products use less material, no REE, and are thinner, lighter, more robust and ecologically greener in the manufacture process. QPS predicts that Quantum Dot possibilities will become product realities and increase the standard of living for the people of the world as electricity becomes portable and plentiful while at the same time electronic products become ubiquitous and inexpensive, and that Quantum Materials Corporation quantum dots are now available to help make this revolution happen.
Looking for more information about Quantum Materials Corporation? Be sure to visit their website at http://www.qmcdots.com.