A U of T Engineering innovation could make printing cells as easy and inexpensive as printing a newspaper. Dr. Hairen Tan and his team have cleared a critical manufacturing hurdle in the development of a relatively new class of solar devices called perovskite solar cells. This alternative solar technology could lead to low-cost, printable solar panels capable of turning nearly any surface into a power generator.
“Economies of scale have greatly reduced the cost of silicon manufacturing,” says University Professor Ted Sargent (ECE), an expert in emerging solar technologies and the Canada Research Chair in Nanotechnology and senior author on the paper. “Perovskite solar cells can enable us to use techniques already established in the printing industry to produce solar cells at very low cost. Potentially, perovskites and silicon cells can be married to improve efficiency further, but only with advances in low-temperature processes.”
Today, virtually all commercial solar cells are made from thin slices of crystalline silicon which must be processed to a very high purity. It’s an energy-intensive process, requiring temperatures higher than 1,000 degrees Celsius and large amounts of hazardous solvents.
In contrast, perovskite solar cells depend on a layer of tiny crystals — each about 1,000 times smaller than the width of a human hair — made of low-cost, light-sensitive materials. Because the perovskite raw materials can be mixed into a liquid to form a kind of ‘solar ink’, they could be printed onto glass, plastic or other materials using a simple inkjet process.
But, until now, there’s been a catch: in order to generate electricity, electrons excited by solar energy must be extracted from the crystals so they can flow through a circuit. That extraction happens in a special layer called the electron-selective layer, or ESL. The difficulty of manufacturing a good ESL has been one of the key challenges holding back the development of perovskite solar cell devices.
“The most effective materials for making ESLs start as a powder and have to be baked at high temperatures, above 500 degrees Celsius,” says Tan. “You can’t put that on top of a sheet of flexible plastic or on a fully fabricated silicon cell — it will just melt.”
Tan and his colleagues developed a new chemical reaction than enables them to grow an ESL made of nanoparticles in solution, directly on top of the electrode. While heat is still required, the process always stays below 150 degrees C, much lower than the melting point of many plastics.
The new nanoparticles are coated with a layer of chlorine atoms, which helps them bind to the perovskite layer on top — this strong binding allows for efficient extraction of electrons. In a paper recently published in Science, Tan and his colleagues report the efficiency of solar cells made using the new method at 20.1 per cent.
“This is the best ever reported for low-temperature processing techniques,” says Tan. He adds that perovskite solar cells using the older, high-temperature method are only marginally better at 22.1 per cent, and even the best silicon solar cells can only reach 26.3 per cent.
Another advantage is stability. Many perovskite solar cells experience a severe drop in performance after only a few hours, but Tan’s cells retained more than 90 per cent of their efficiency even after 500 hours of use. “I think our new technique paves the way toward solving this problem,” says Tan, who undertook this work as part of a Rubicon Fellowship.
“The Toronto team’s computational studies beautifully explain the role of the newly developed electron-selective layer. The work illustrates the rapidly-advancing contribution that computational materials science is making towards rational, next-generation energy devices,” said Professor Alán Aspuru-Guzik, an expert on computational materials science in the Department of Chemistry and Chemical Biology at Harvard University, who was not involved in the work.
“To augment the best silicon solar cells, next-generation thin-film technologies need to be process-compatible with a finished cell. This entails modest processing temperatures such as those in the Toronto group’s advance reported in Science,” said Professor Luping Yu of the University of Chicago’s Department of Chemistry. Yu is an expert on solution-processed solar cells and was not involved in the work.
Keeping cool during the manufacturing process opens up a world of possibilities for applications of perovskite solar cells, from smartphone covers that provide charging capabilities to solar-active tinted windows that offset building energy use. In the nearer term, Tan says his technology could be used in tandem with conventional solar cells.
“With our low-temperature process, we could coat our perovskite cells directly on top of silicon without damaging the underlying material,” says Tan. “If a hybrid perovskite-silicon cell can push the efficiency up to 30 per cent or higher, it makes solar power a much better economic proposition.”
Learn more: Printable solar cells just got a little closer
Receive an email update when we add a new SOLAR CELLS article.
The Latest on: Solar cells
via Google News
The Latest on: Solar cells
- New report: Global Solar Panel Recycling Management market research on December 17, 2018 at 5:51 am
Global Solar Panel Recycling Management Market: How Technology Is Changing with business opportunities and threats, challenges to industry growth during forecast period 2018-2023. Increasing demand fo... […]
- Hanwha Q CELLS surpasses 10 GW of Q.ANTUM solar cell production - first time ever for any PERC technology on December 17, 2018 at 5:29 am
- Hanwha Q CELLS passed the 10 GW production mark for its proprietary Q.ANTUM solar cell technology - The Company will end 2018 having produced more than 2.5 billion individual Q.ANTUM cells since ... […]
- Hanwha Q Cells Surpasses 10GW of PERC Q.ANTUM Cells on December 17, 2018 at 4:51 am
Hanwha Q CELLS, one of the largest solar cell and module manufacturers in the world, today announced that it has surpassed the 10GW threshold for production of the company’s proprietary Q.ANTUM cell t... […]
- Pioneer looks at solar plan on December 17, 2018 at 4:49 am
NORTHFIELD — Solar panels on the roof could cut energy costs for Pioneer Valley Regional School by a quarter and would cost the school nothing, district Business Manager Tanya Gaylord said. Plans for ... […]
- Soft-serve sculpture and solar cells you can wear: 5 material innovations that will shape tomorrow on December 16, 2018 at 6:26 pm
Seetal Solanki is the founder and director of materials research design studio Ma-t-ter, and author of "'Why Materials Matter: Responsible Design for a Better World," published by Prestel. For us to l... […]
- Starting in 2020, all new homes in California must come with solar panels. Builders are getting ready on December 16, 2018 at 8:00 am
When Irvine-based City Ventures started sticking solar panels on all of its homes six year ago, the builder emerged as a front-runner in the race toward energy-efficient home building. Soon it will be ... […]
- Why President Trump’s Solar Tariffs Have Failed on December 16, 2018 at 5:02 am
When President Trump put a 30% tariff on most imported solar panels and cells, it was supposed to be a needle in the side of the solar industry and was also meant to drive more investment in U.S. sola... […]
- Austin High School installs over 200 solar panels on December 15, 2018 at 4:23 pm
AUSTIN — Stephen F. Austin High School has installed over 200 solar panels, as part of Austin ISD's plan to cut down energy costs. While students normally aren't allowed to get on Austin High's roof, ... […]
- How Many Solar Panels Do I Need? on December 14, 2018 at 8:50 pm
“How many solar panels do I need?” is typically the first question most of us have around solar. Even I, the author who has worked in the industry for years, continue to ask myself that question all t... […]
via Bing News