Ultrathin, flexible photovoltaic cells from MIT research could find many new uses
Imagine solar cells so thin, flexible, and lightweight that they could be placed on almost any material or surface, including your hat, shirt, or smartphone, or even on a sheet of paper or a helium balloon.
Researchers at MIT have now demonstrated just such a technology: the thinnest, lightest solar cells ever produced. Though it may take years to develop into a commercial product, the laboratory proof-of-concept shows a new approach to making solar cells that could help power the next generation of portable electronic devices.
The new process is described in a paper by MIT professor Vladimir Bulovic, research scientist Annie Wang, and doctoral student Joel Jean, in the journal Organic Electronics.
Bulovic, MIT’s associate dean for innovation and the Fariborz Maseeh (1990) Professor of Emerging Technology, says the key to the new approach is to make the solar cell, the substrate that supports it, and a protective overcoating to shield it from the environment, all in one process. The substrate is made in place and never needs to be handled, cleaned, or removed from the vacuum during fabrication, thus minimizing exposure to dust or other contaminants that could degrade the cell’s performance.
“The innovative step is the realization that you can grow the substrate at the same time as you grow the device,” Bulovi? says.
In this initial proof-of-concept experiment, the team used a common flexible polymer called parylene as both the substrate and the overcoating, and an organic material called DBP as the primary light-absorbing layer. Parylene is a commercially available plastic coating used widely to protect implanted biomedical devices and printed circuit boards from environmental damage. The entire process takes place in a vacuum chamber at room temperature and without the use of any solvents, unlike conventional solar-cell manufacturing, which requires high temperatures and harsh chemicals. In this case, both the substrate and the solar cell are “grown” using established vapor deposition techniques.
One process, many materials
The team emphasizes that these particular choices of materials were just examples, and that it is the in-line substrate manufacturing process that is the key innovation. Different materials could be used for the substrate and encapsulation layers, and different types of thin-film solar cell materials, including quantum dots or perovskites, could be substituted for the organic layers used in initial tests.
But already, the team has achieved the thinnest and lightest complete solar cells ever made, they say. To demonstrate just how thin and lightweight the cells are, the researchers draped a working cell on top of a soap bubble, without popping the bubble. The researchers acknowledge that this cell may be too thin to be practical — “If you breathe too hard, you might blow it away,” says Jean — but parylene films of thicknesses of up to 80 microns can be deposited easily using commercial equipment, without losing the other benefits of in-line substrate formation.
A flexible parylene film, similar to kitchen cling-wrap but only one-tenth as thick, is first deposited on a sturdier carrier material – in this case, glass. Figuring out how to cleanly separate the thin material from the glass was a key challenge, explains Wang, who has spent many years working with parylene.
The researchers lift the entire parylene/solar cell/parylene stack off the carrier after the fabrication process is complete, using a frame made of flexible film. The final ultra-thin, flexible solar cells, including substrate and overcoating, are just one-fiftieth of the thickness of a human hair and one-thousandth of the thickness of equivalent cells on glass substrates — about two micrometers thick — yet they convert sunlight into electricity just as efficiently as their glass-based counterparts.
No miracles needed
“We put our carrier in a vacuum system, then we deposit everything else on top of it, and then peel the whole thing off,” explains Wang. Bulovic says that like most new inventions, it all sounds very simple — once it’s been done. But actually developing the techniques to make the process work required years of effort.
While they used a glass carrier for their solar cells, Jean says “it could be something else. You could use almost any material,” since the processing takes place under such benign conditions. The substrate and solar cell could be deposited directly on fabric or paper, for example.
While the solar cell in this demonstration device is not especially efficient, because of its low weight, its power-to-weight ratio is among the highest ever achieved. That’s important for applications where weight is important, such as on spacecraft or on high-altitude helium balloons used for research. Whereas a typical silicon-based solar module, whose weight is dominated by a glass cover, may produce about 15 watts of power per kilogram of weight, the new cells have already demonstrated an output of 6 watts per gram — about 400 times higher.
“It could be so light that you don’t even know it’s there, on your shirt or on your notebook,” Bulovic says. “These cells could simply be an add-on to existing structures.”
Still, this is early, laboratory-scale work, and developing it into a manufacturable product will take time, the team says. Yet while commercial success in the short term may be uncertain, this work could open up new applications for solar power in the long term. “We have a proof-of-concept that works,” Bulovic says. The next question is, “How many miracles does it take to make it scalable? We think it’s a lot of hard work ahead, but likely no miracles needed.”
“This demonstration by the MIT team is almost an order of magnitude thinner and lighter” than the previous record holder, says Max Shtein, an associate professor of materials science and engineering, chemical engineering, and applied physics, at the University of Michigan, who was not involved in this work. As a result, he says, it “has tremendous implications for maximizing power-to-weight (important for aerospace applications, for example), and for the ability to simply laminate photovoltaic cells onto existing structures.”
Learn more: Solar cells as light as a soap bubble
The Latest on: Solar-cell manufacturing
[google_news title=”” keyword=”solar-cell manufacturing” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Solar-cell manufacturing
- Global solar manufacturing sector now at 50% utilization rate, says IEAon May 8, 2024 at 8:14 am
The International Energy Agency (IEA) says that global solar cell and module manufacturing capacity grew by around 550 GW in 2023. It reports that around 80% of the global PV manufacturing industry is ...
- A low-energy process for high-performance solar cells could simplify the manufacturing processon May 8, 2024 at 7:39 am
Finding reliable, eco-friendly power sources is crucial as our world grapples with increasing energy needs and the urgent call to combat climate change. Solar energy offers one solution, with ...
- Renewables manufacturing was 4% of 2023 GDP growthon May 7, 2024 at 5:00 pm
The IEA said that current solar module and cell production facilities are seeing “relatively low average utilisation rates of around 50% globally.” It attributed this to a “module supply glut” and ...
- The Australian Government’s Manufacturing Objectives Rely on IT Capabilitieson May 7, 2024 at 2:02 pm
The intent of the Future Made in Australia Act is to build manufacturing capabilities across all sectors, which will likely lead to more demand for IT skills and services.
- Solar, battery manufacturing could help Net Zero become reality — but demand lags behindon May 6, 2024 at 10:21 am
A new International Energy Agency report found that the current global manufacturing capacity for solar cells and modules could meet the sector’s target to realize a Net Zero emissions scenario by ...
- Accelerated declines in solar cell prices since late Marchon May 6, 2024 at 10:10 am
In a new weekly update for pv magazine, OPIS, a Dow Jones company, offers bite-sized analysis on solar PV module supply and price trends.
- Recent fires may impact production output for two leading solar panel manufacturerson May 6, 2024 at 5:42 am
Two solar panel manufacturers have experienced fires at factories in recent weeks that may affect production for months to come. JinkoSolar revealed that ...
- New water circulation tech promises lower PERC solar cell manufacturing costson May 1, 2024 at 5:00 pm
A German team developed models to illustrate water-saving potential in PERC silicon solar cell manufacturing based on a circular approach and commercially available technology. In the case of a 5 GW ...
- Federal Policies and Incentives Drive Demand for American-Made Solar Power Moduleson May 1, 2024 at 3:11 am
The U.S. was one of the world leaders in solar equipment manufacturing a few decades ago, but then the Chinese stole the show. Now, however, American companies are finding a lot of new opportunities a ...
- Boviet Solar to build 2GW cell and module assembly plant in North Carolinaon April 30, 2024 at 3:08 am
Boviet Solar will build its first North American production facility in Greenville, Pitt County, in the US state of North Carolina.
via Bing News