|Dr Carmel Rotschild leads a multidisciplinary team that develops innovative applications to maximize the energy harnessed from the sun.
By Georgina Johnson
On the one hand we have sunlight - an infinite source of energy - with a broad spectrum of every bandwidth in creation. On the other, we have silicon - an abundant material made from sand and the front-runner as the material most likely to be used in photovoltaic cells for your solar energy panels. Between the simplicity of silicon and the broad spectrum of sunlight, falls the innovation.
As oil reserves deplete and energy prices rise, solar power is emerging as an essential source of clean, affordable energy. The scientific searchlights are on for new discoveries that could make solar energy competitive with fossil fuels.
Technion new recruit, Dr Carmel Rotschild, who arrived in August 2011 at the Faculty of Mechanical Engineering from MIT, is aiming to do just that. His dream is to increase the efficiency of photovoltaics by around 20 percent, by developing efficient appliances to convert the lost rays of the sun that silicon is unable to process. This involves the fusion (or up conversion) of infrared solar radiation to make that power accessible to silicon, and the fission (or down conversion) of radiation in the blue range to near infrared radiation, which could double the quantum efficiency of photovoltaics. The highly multidisciplinary approach includes the design and fabrication of nanoscale optical materials within an optical cavity, and Rotschild and his multidisciplinary team draws on expertise in nonlinear optics, material engineering, and energy transfer in molecules.
“My vision is to increase efficiency by 20 percent for a given photovoltaic cell.“
“What I’m doing in my research is combining nonlinear optics and luminescent solar concentrators to build accessories for photovoltaics,” explains Rotschild. “My vision is to increase efficiency by 20 percent for a given photovoltaic cell. The main issue that limits efficiency is the mismatch between the broad solar spectrum, and the narrow spectral response of photovoltaics. For example: silicon is very effective at one micron wavelength, but light with a longer wavelength cannot be converted into electricity by silicon solar cells. It would be nice to look at nonlinear optics as a toolbox for converting inefficient parts of the solar spectrum into emissions where solar panels can be more efficient.”
Rotschild has a personal passion for creating cleaner, more efficient ways to power our world: he lost a friend to cancer and is concerned that air pollution was a chief culprit. And his belief in the urgency of the need to advance energy research in Israel is shared by the Grand Technion Energy Program (GTEP) and the Russell Berrie Nanotechnology Institute (RBNI) who are jointly supporting his work.
“The energy revolution is already here, and the funny thing is it doesn’t come from science, it comes from engineering,” says Rotschild. “If you include the cost that we as a society pay for using petrol, coal and fossil fuels in terms of health and pollution, we are now even in the cost we can pay... we are reaching an era where solar energy becomes affordable for society.”
Rotschild says that multidisciplinary programs such as GTEP are powerful platforms for attracting scientists back to Israel. “Energy is a key part of the Technion vision, and my lab is evidence of that,” he says. “GTEP is a great platform to interact and collaborate in order for Israel to become a world leader in this field. It is really a great vision and I think we are reaching it.”
Dr Carmel Rotschild is a Horev Fellow in the Leaders in Science and Technology Program.