Biological manufacturing process, pioneered by three Lehigh University engineers, produces equivalent quantum dots to those made chemically–but in a much greener, cheaper way
Quantum dots (QDs) are semiconducting nanocrystals prized for their optical and electronic properties. The brilliant, pure colors produced by QDs when stimulated with ultraviolet light are ideal for use in flat screen displays, medical imaging devices, solar panels and LEDs. One obstacle to mass production and widespread use of these wonder particles is the difficulty and expense associated with current chemical manufacturing methods that often requiring heat, high pressure and toxic solvents.
But now three Lehigh University engineers have successfully demonstrated the first precisely controlled, biological way to manufacture quantum dots using a single-enzyme, paving the way for a significantly quicker, cheaper and greener production method. Their work was recently featured in an article in The New York Times called “A curious tale of quantum dots.”
The Lehigh team– Bryan Berger, Class of 1961 Associate Professor, Chemical and Biomolecular Engineering; Chris Kiely, Harold B. Chambers Senior Professor, Materials Science and Engineering and Steven McIntosh, Class of 1961 Associate Professor, Chemical and Biomolecular Engineering, along with Ph.D. candidate Li Lu and undergraduate Robert Dunleavy–have detailed their findings in an article called “Single Enzyme Biomineralization of Cadmium Sulfide Nanocrystals with Controlled Optical Properties” published in theProceedings of the National Academy of Sciences (PNAS).
“The beauty of a biological approach is that it cuts down on the production needs, environmental burden and production time quite a lot,” says Berger.
In July of last year, the team’s work was featured on the cover of Green Chemistry describing their use of “directed evolution” to alter a bacterial strain called Stenotophomonas maltophilia to selectively produce cadmium sulphide QDs. Because they discovered that a single enzyme produced by the bacteria is responsible for QD generation, the cell-based production route was scrapped entirely. The cadmium sulphide QDs, as they have now shown in the PNAS article, can be generated with the same enzyme synthesized from other easily engineered bacteria such as E. coli.
“We have evolved the enzyme beyond what nature intended,” says Berger, engineering it to not only make the crystal structure of the QDs, but control their size. The result is the ability to uniformly produce quantum dots that emit any particular color they choose–the very characteristic that makes this material attractive for many applications.
Industrial processes take many hours to grow the nanocrystals, which then need to undergo additional processing and purifying steps. Biosynthesis, on the other hand, takes minutes to a few hours maximum to make the full range of quantum dot sizes (about 2 to 3 nanometers) in a continuous, environmentally friendly process at ambient conditions in water that needs no post-processing steps to harvest the final, water-soluble product.
Perfecting the methodology to structurally analyze individual nanoparticles required a highly sophisticated Scanning Transmission Electron Microscope (STEM). Lehigh’s Electron Microscopy and Nanofabrication Facility was able to provide a $4.5 million state-of-the-art instrument that allowed the researchers to examine the structure and composition of each QD, which is only composed of tens to hundreds of atoms.
“Even with this new microscope, we’re pushing the limits of what can be done,” says Kiely.
The instrument scans an ultra-fine electron beam across a field of QDs. The atoms scatter the electrons in the beam, producing a kind of shadow image on a fluorescent screen, akin to the way an object blocking light produces a shadow on the wall. A digital camera records the highly magnified atomic resolution image of the nanocrystal for analysis.
The team is poised to scale-up its laboratory success into a manufacturing enterprise making inexpensive QDs in an eco-friendly manner. Conventional chemical manufacturing costs $1,000 to $10,000 per gram. A biomanufacturing technique could potentially slash the price by at least a factor of 10, and the team estimates yields on the order of grams per liter from each batch culture, says McIntosh.
Taking a long view, the three colleagues hope that their method will lead to a plethora of future QD applications, such as greener manufacturing of methanol, an eco-friendly fuel that could be used for cars, heating appliances and electricity generation. Water purification and metal recycling are two other possible uses for this technology.
“We want to create many different types of functional materials and make large-scale functional materials as well as individual quantum dots,” says McIntosh.
He imagines developing a process by which individual quantum dots arrange themselves into macrostructures, the way nature grows a mollusk shell out of individual inorganic nanoparticles or humans grow artificial tissue in a lab.
“If we’re able to make more of the material and control how it’s structured while maintaining its core functionality, we could potentially get a solar cell to assemble itself with quantum dots.”
The Latest on: Quantum dots
via Google News
The Latest on: Quantum dots
- HDTV Question: Is Samsung's QLED Technology a Scam Or Worth the Money?on March 23, 2020 at 4:14 pm
HDTV Question: Is Samsung's QLED Technology a Scam Or Worth the Money? In short, a QLED TV is just an LCD TV with quantum dots, which are microscopic particles that when hit by light, emit a certain ...
- Quantum Workplace Cited Among Most Significant Employee Experience (EX) Management Platforms by Leading Market Research Firmon March 23, 2020 at 3:21 am
Quantum Workplace helps leaders connect the dots between engagement and performance with intuitive and user-friendly tools including comprehensive and automated employee surveys; goal setting and ...
- Global Quantum Dot Display Market 2020 – Samsung, LG, Sharp, CSOT, AUOon March 22, 2020 at 1:37 am
The report involves insightful data on the main sectors of the Global Quantum Dot Display Market. The report has segmented market, by its types and applications. Each segment has analyzed completely ...
- 2020 Innovations in Nanoencapsulation, Nanocomposites, Nanofibrous Coatings, and Quantum Dots - ResearchAndMarkets.comon March 20, 2020 at 4:06 am
DUBLIN--(BUSINESS WIRE)--The "Innovations in Nanoencapsulation, Nanocomposites, Nanofibrous Coatings, and Quantum Dots" report has been added to ResearchAndMarkets.com's offering. This issue of the ...
- Optical Fredkin gate assisted by quantum dot within optical cavity under vacuum noise and sideband leakageon March 20, 2020 at 3:18 am
We propose a deterministic Fredkin gate which can accomplish controlled-swap operation between three-qubit states. The proposed Fredkin gate consists of a photonic system (single photon) and quantum ...
- Spin-photon module for scalable network architecture in quantum dotson March 19, 2020 at 3:10 am
Reliable information transmission between spatially separated nodes is fundamental to a network architecture for scalable quantum technology. Spin qubit in semiconductor quantum dots is a promising ...
- Colloidal Assembly of Au–Quantum Dot–Au Sandwiched Nanostructures with Strong Plasmon–Exciton Couplingon March 14, 2020 at 2:50 am
This work demonstrates strongly coupled metal–semiconductor nanostructures can be constructed using colloidal assembly. Specifically, sandwiched Au–quantum dot–Au nanostructures were created through ...
- AGR: Curious case of how Airtel, Vodafone Idea paid lower than DoT’s estimated dueson March 12, 2020 at 10:17 pm
It is not clear how it will look at the telecom operators paying amounts lower than the DoT’s assessment. “The SC may not rule on the quantum of the dues. Technically, the TDSAT is equipped to handle ...
- Quantum Dot Sensors Market 2020, Global Trends, Opportunity and Growth Analysis Forecast by 2026on March 11, 2020 at 11:09 pm
The report provides a unique tool for evaluating the market, highlighting opportunities, and supporting strategic and tactical decision-making. This report recognizes that in this rapidly-evolving and ...
- ORNL’s Raphael Pooser on DoE’s Quantum Testbed Projecton March 11, 2020 at 10:24 am
That doesn’t just include Intel. Speaking broadly, the silicon quantum dot-based qubit (Intel) is a very interesting system. Those are hard to benchmark now because access to those systems is limited.
via Bing News