LED

Riccardo Comin, a postdoctoral fellow in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering, has won the 2015 John Charles Polanyi Prize for Physics for his research into a rapidly emerging new class of materials, called perovskites, for more efficient solar cells and lighting.

The Polanyi Prizes are given annually to outstanding researchers in the early stages of their careers. The prizes, worth $20,000 each, are awarded in five areas: physics, chemistry, physiology or medicine, literature and economic science. Comin is the only recipient from the ��Ƶ this year. (Read about some of U of T's previous Polanyi Prize winners.)

“By scientific upbringing, I’m a solid state physicist,” said Comin. “I take new compounds, films or crystals, crafted by chemists, and I analyze them to figure out what’s special about those materials.”

Comin’s work, under the direction of Professor Ted Sargent, is to investigate the mysterious properties of a very special family of hybrid organic-inorganic materials called perovskites. Perovskites show great promise for a range of applications, from more efficient LED technologies to high-efficiency flexible and lightweight solar cells.

Read more about Comin’s recent work, published in the journals Science and Nature:

“My work in the Sargent Group has been to explore various key characteristics of perovskites, including their chemical composition, crystalline structure, and electronic structure,” said Comin. “Thanks to the Polanyi Prize, I plan to expand my work into using x-ray methods to look at the collective phenomena involving the reorientation of the organic molecules embedded in the inorganic crystalline structure of these hybrid materials.”

Comin earned his bachelor’s and master’s degrees at the Universita degli Studi di Trieste in Italy, both in physics. He completed his PhD at the University of British Columbia under the supervision of Andrea Damascelli, where he worked on characterizing quantum materials. When he joined the Sargent Group for his postdoctoral fellowship, he was ready to take a more applied approach to his research.

“I’d done a lot of fundamental materials science, and I was thinking, ‘What are the strategies and processes involved in harnessing and functionalizing the material properties that are key for devices that realize solar, imaging or lighting applications?’” he said “Here, we’re trying not just to develop high-quality materials, but also to combine them into device architectures that use the best properties of these materials. Ultimately, the metric for the quality of the work is the efficiency and performance of our devices.”

The John Charles Polanyi prize was created in honour of the achievement of John Charles Polanyi, recipient of the 1986 Nobel Prize in Chemistry and a professor in the ��Ƶ’s department of chemistry.

“My congratulations to Riccardo, who is doing exceptional research,” said Professor Sargent, vice-dean, research for the Faculty of Applied Science & Engineering, and Comin’s supervisor.

“It’s particularly wonderful to see him honoured with this award, named after one of the greatest investigators in the ��Ƶ’s long history.”

Learn more about the other 2015 John Charles Polanyi winners

Marit Mitchell is a writer with the Faculty of Applied Science & Engineering at the ��Ƶ

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Nanoleaf launches new product for Apple home system

sgupta — Tue, 27 Oct 2015 16:25:27 +0000

Nanoleaf launches new product for Apple home system sgupta Tue, 10/27/2015 - 12:25

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The Nanoleaf Ivy bulb (hanging) and hub (on table) work in connection with Apple HomeKit

Brianna Goldberg

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Brianna Goldberg

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Siri lets users wirelessly control alumni’s award-winning super-efficient LED bulbs

Nanoleaf, the fast-growing startup from ��Ƶ alumni, launched a new product Oct. 27 tied to Apple's HomeKit line.

“We've received Apple's approval to join the HomeKit ecosystem,” said Nanoleaf spokesperson Leslie Chen.

The Nanoleaf Smarter Kit combines “the world’s most energy efficient smart bulb” and a stylish, connected hub with Apple’s Siri-enabled HomeKit, Chen said. This will allow users to wirelessly control the startup’s award-winning LED bulb designs by simply using their voice. (Read more about Nanoleaf and the new Nanoleaf Smarter Kit)

“With the emergence of smart home products, lighting is entering a whole new territory,” said Chen, one of a growing number of recent U of T grads recruited to Nanoleaf.

“Imagine sitting in the living room and being able to control all of the lights in your home with just a few words,” she said. “Pretty revolutionary to say the least!”

Chen said the Ivy is an app-controlled bulb that users can turn on, off and dim using their Apple phone, tablet or smart watch. The Nanoleaf Smarter Kit is set for release in selected Best Buy locations in early November, she added, with more details still to come.

“Integrating technology like this, especially through a company as famed as Apple, is a great way to reach a wider audience and get access to a new market,” said Karen Sievewright, managing director of U of T's Banting & Best Centre for Innovation & Entrepreneurship. “It’s a smart move by Nanoleaf.”

The green tech startup founded by Engineering alumni Gimmy Chu, Christian Yan and Tom Rodinger has grown from a massively successful Kickstarter project in early 2013, based on the strength of their stylish “world’s most energy efficient” bulb, to a bustling company with approximately 40 employees spread between its Toronto and Shenzhen, China, offices.

The venture recently scored funding from ‘Asia’s richest philanthropist,’ debuted products at fairs in New York, Shanghai and Tokyo and won a reddot design award for 2015.

Read about Nanoleaf’s Kickstarter surpassing its goal by 500 per cent

Read about ‘Asia’s richest philanthropist’ investing in Nanoleaf

Read about Nanoleaf creating green jobs in Canada and China

Read about Nanoleaf’s revolutionary dimming bulb

Chen says the next big step for Nanoleaf will be releasing a product they believe will change the way people think about lighting.

“Light is not merely illumination. Light is atmosphere, it wakes you up after a night of sleep, it keeps us safe and content, just as much today as two million years ago,” said Chu, CEO of Nanoleaf. “We want to make products that will transform simple lighting solutions into meaningful experiences.”

Nanoleaf made the announcement as U of T's Impact Centre prepared to host a symposium celebrating the International Year of Light. (Read more about the IYL Symposium)

Chen says the gains of Nanoleaf rely on the team members they continue to recruit from U of T.

“The U of T presence is still very strong at Nanoleaf, and I believe it always will be,” said Chen. “When we were looking for interns to join our team, the first place we looked was at U of T.”

Watch for U of T News stories profiling Nanoleaf's three undergrad interns, Jeanny Yao, Frank Gu and Josh Hwang in the coming week.

“Nanoleaf will always be very closely connected with U of T: our three founders are all alumni and without the school, they would have never met in the first place,” said Chen.

“It will always be part of our identity and I think that’s why U of T grads are a good fit for us.”

(Video courtesy Nanoleaf's Smarter Kit Indiegogo)

Learn more about entrepreneurships and startups at U of T: visit the Banting & Best Centre for Entrepreneurship.

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Fiat lux: what do you get when you combine perovskite and colloidal dots?

sgupta — Fri, 17 Jul 2015 10:07:14 +0000

Fiat lux: what do you get when you combine perovskite and colloidal dots? sgupta Fri, 07/17/2015 - 06:07

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Riccardo Comin (left) and Xiwen Gong combined two different materials to create new hyper-efficient light-emitting crystal (photo by Marit Mitchell)

Marit Mitchell

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Marit Mitchell

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U of T researchers engineer hybrid solar-power crystal that opens new frontiers in high-efficiency lighting

It’s snack time: you have a plain oatmeal cookie, and a pile of chocolate chips. Both are delicious on their own but if you can find a way to combine them smoothly, you get the best of both worlds.

Researchers in the ��Ƶ's Edward S. Rogers Sr. Department of Electrical & Computer Engineering used this insight to invent something totally new: they’ve combined two promising solar cell materials together for the first time, creating a new platform for LED technology.

The team designed a way to embed strongly luminescent nanoparticles called colloidal quantum dots (the chocolate chips) into perovskite (the oatmeal cookie). Perovskites are a family of materials that can be easily manufactured from solution, and that allow electrons to move swiftly through them with minimal loss or capture by defects.

A glowing quantum dot seamlessly integrated into a perovskite crystal matrix (Image: Ella Marushchenko).

The work was published July 15 in the international journal Nature.

“It’s a pretty novel idea to blend together these two optoelectronic materials, both of which are gaining a lot of traction,” said Xiwen Gong, one of the study’s lead authors and a PhD candidate working with Professor Ted Sargent. “We wanted to take advantage of the benefits of both by combining them seamlessly in a solid-state matrix.”

The result is a black crystal that relies on the perovskite matrix to ‘funnel’ electrons into the quantum dots, which are extremely efficient at converting electricity to light. Hyper-efficient LED technologies could enable applications from the visible-light LED bulbs in every home, to new displays, to gesture recognition using near-infrared wavelengths.

“When you try to jam two different crystals together, they often form separate phases without blending smoothly into each other,” said Riccardo Comin, a post-doctoral fellow in the Sargent Group.

“We had to design a new strategy to convince these two components to forget about their differences and to rather intermix into forming a unique crystalline entity.”

The main challenge was making the orientation of the two crystal structures line up, called heteroexpitaxy. To achieve heteroepitaxy, Gong, Comin and their team engineered a way to connect the atomic ‘ends’ of the two crystalline structures so that they aligned smoothly, without defects forming at the seams.

“We started by building a nano-scale scaffolding ‘shell’ around the quantum dots in solution, then grew the perovskite crystal around that shell so the two faces aligned,” explained coauthor Zhijun Ning, who contributed to the work while a post-doctoral fellow at UofT and is now a faculty member at ShanghaiTech.

The resulting heterogeneous material is the basis for a new family of highly energy-efficient near-infrared LEDs. Infrared LEDs can be harnessed for improved night-vision technology, to better biomedical imaging, to high-speed telecommunications.

Combining the two materials in this way also solves the problem of self-absorption, which occurs when a substance partly re-absorbs the same spectrum of energy that it emits, with a net efficiency loss.

“These dots in perovskite don’t suffer reabsorption, because the emission of the dots doesn’t overlap with the absorption spectrum of the perovskite,” Comin said.

Gong, Comin and the team deliberately designed their material to be compatible with solution-processing, so it could be readily integrated with the most inexpensive and commercially practical ways of manufacturing solar film and devices.

Their next step is to build and test the hardware to capitalize on the concept they have proven with this work.

“We’re going to build the LED device and try to beat the record power efficiency reported in the literature,” Gong said.

This work was supported by the Ontario Research Fund Research Excellence Program, the Natural Sciences and Engineering Research Council of Canada (NSERC), and the King Abdullah University of Science & Technology (KAUST).

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