One of the most promising technologies for making inexpensive but reasonably efficient solar photovoltaic cells just got much cheaper. Scientists at the University of Toronto have shown that inexpensive nickel can work just as well as gold for one of the critical electrical contacts that gather the electrical current produced by their colloidal quantum dot solar cells.

The change to nickel can reduce the cell’s already low material costs by 40 to 80 percent, says Lukasz Brzozowski, the director of the Photovoltaics Research Program within the research group of Professor Ted Sargent (ECE). The research was presented in the July 12, 2010 issue of Applied Physics Letters, published by the American Institute of Physics.

Quantum dots are nanoscale bits of a semiconductor material that are created using low-cost,high-throughput chemical reactions in liquid solutions. Since their properties vary according to their size, quantum dots can be made to match the illumination spectrum. Professor Sargent’s group has pioneered the design and development of quantum dot solar cells that gather both visible and infrared light. The researchers have reached a power-conversion efficiency as high as 5 percent and aim to improve that to 10 percent before commercialization.

At first, nickel did not appear to do the job. But adding just one nanometer of lithium fluoride between the nickel and the dots created a barrier that stopped the contamination, and the cell’s efficiency jumped back up to the expected level.

This is the latest of several recent solar-cell milestones by the Canadian researchers. “We have been able to increase dramatically the efficiency of our photovoltaics over the last several years and continue to hold the performance world records,” Professor Sargent said.

Using your brain waves to control the environment around you, like the lights in your home or even your toaster, is already a reality. One Toronto-based company has developed a system called thought-control computing, and it is exploring a range of commercial opportunities that include screens on airplanes and video games.

Its philosophy is simple: if you can plug it in, you can control it with your brain. Ariel Garten, CEO of InteraXon, says the possibilities are endless. The technology involves a regular-looking headset, but embedded with electrodes that read brain waves. The brain waves are then processed on a computer.

The technology was demonstrated earlier this year at the Vancouver Olympics where visitors used their brain waves to control the lighting on three landmarks: the CN Tower, the Parliament buildings and Niagara Falls.

Garten was a student of Professor Steve Mann (ECE), credited with pioneering thought-controlled computing technology.

One of the fundamental tenets of quantum mechanics is that measuring a physical system always disturbs it. If the system in question is a message in a series of digital bits encoded in the polarisation of light, this means that intercepting and reading the message can no longer be done surreptitiously. The receiver should be able to detect an eavesdropper and take appropriate countermeasures.

In practice, quantum-key-distribution systems rely on sophisticated optical equipment to prepare, transmit and detect the individual polarised photons that make up the key. And when these real-world components meet the clever academic theorems that guarantee security, holes emerge.

Research conducted by the Norwegian University of Science and Technology, the National University of Singapore and the University of Toronto hacked into a system that connects several buildings on the National University of Singapore’s campus. For the first hack, small eavesdropping apparatus was designed to take advantage of a weakness in a particular kind of photon detector in the receiver’s receiving equipment. The second hack was carried out by a team from the University of Toronto, led by Professor Hoi-Kwong Lo (ECE), which stole information from a research version of a system made by ID Quantique—a Swiss firm trying to commercialise quantum cryptography—by taking advantage of synchronisation signals that pass between the sender and receiver.

As quantum hackers continue to put systems through their paces, such loopholes will be closed—as these now have been—and the systems become more secure.

Follow the link to read the full article in The Economist.

As the semiconductors that power the chips and lasers responsible for computing information shrink down to the nano-scale, they produce higher levels of electrical resistance and capacitance that ultimately slow performance. In recent years a research team, led by University of Toronto professors Doug Perovic (MSE) and Geoffrey Ozin of the Department of Chemistry, has been seeking to solve this problem by creating a new class of materials.

The material, known as periodic mesoporous organosilica (PMO), is a thin nano-porous film. It was created by mixing an organosilica precursor containing organic groups with a surfactant in an aqueous solution which causes the organosilica to self-assemble into a nano-structure. When the surfactant was washed away, it left a nano-porous material,  which the researchers discovered made an excellent dielectric material that could significantly improve the speed and reduce crosstalk of information transferred between the tiny wires inside microelectronic devices. The PMO acts as a better dielectric, allowing transistor components to shrink even further.

“We recently developed a vapour phase delivery technique, called vacuum assisted aerosol deposition (VAAD), and have investigated the properties most related to low-k [low dielectric constant] applications,” says materials chemistry PhD student Wendong Wang (Chemistry), who developed the technique. The PMO thin films used in the VAAD technique possess a combination of properties that satisfy the immediate and long-term
needs of the semiconductor industry.

In April, Wang presented the team’s research findings at the Materials Research Society’s spring meeting in San Francisco to overwhelming interest from industry. “Intel started calling us right away,” says Professor Perovic.

Follow the link to read the full article in Engineering Dimensions.

In the midst of a blistering heat wave, most Torontonians aren’t thinking much about frigid temperatures, ice and winter spills. But in a special laboratory at the Toronto Rehabilitation Institute, walking is a perilous — and chilly — experience for volunteers like Varun Ohri.

A 20-year-old from Mississauga, Ont., Ohri is walking for science. Or falling for science, if his supervisor, Jennifer Hsu (MIE, IBBME) is lucky. Ms. Hsu is a biomedical engineer and PhD candidate who specializes in gait biomechanics. She is currently working on a project at this University of Toronto-affiliated hospital that is designed to tease out the hows and whys of winter falls, and most particularly whether they can be avoided.

Ms. Hsu is doing the work for Canada Post, with a grant from Ontario’s Workplace Safety and Insurance Board. “Canada Post really wants to be able to protect their employees. So one of the problems that they know exists is that a lot of people slip and fall,” she says. “So they want to sort of nip it in the bud.”

With so many shale gas reserves available, major energy companies around the world are racing to start drilling. This carries some big environmental risks, but the upside is too great to ignore. Shale gas could one day lower fuel prices, rein in dependence on foreign oil and shrink carbon emissions. “A few years downstream, maybe in the next decade, there will be an energy shortage,” says Olev Trass, a chemical engineering and applied chemistry professor at the University of Toronto. “Shale gas really gives a respite to this whole crisis.”

The shot that kicked off the shale-gas rush came in the form of advancements in horizontal drilling—where a drill turns sideways after boring vertically—and hydraulic fracturing (fracking), a process that uses millions of gallons of high pressure liquid to expand cracks in rock and allow gas to leech out. The techniques have made deposits once far too expensive to access viable, and have caught the interest of fuel giants like Shell, ExxonMobil, Encana, Statoil, and smaller firms like Denver-based Forest Oil and Calgary-based Talisman Energy, both of whom are drilling on the Utica shale in southern Quebec, which is thought to hold over a trillion cubic metres of gas. Billions of dollars have also been invested in exploration and drilling projects in India, China, Australia, Russia and Germany since the mid 2000s.

Follow the link to read the full article in Maclean’s magazine.