Energy

Hybrid solar cell captures energy from the sun and raindrops

Hybrid solar cell captures ene...
A new hybrid solar cell device can capture energy from the sun and from the movement of raindrops
A new hybrid solar cell device can capture energy from the sun and from the movement of raindrops
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The hybrid solar cell uses layers of two polymers to harvest energy from raindrops as well, using the triboelectric effect
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The hybrid solar cell uses layers of two polymers to harvest energy from raindrops as well, using the triboelectric effect
A new hybrid solar cell device can capture energy from the sun and from the movement of raindrops
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A new hybrid solar cell device can capture energy from the sun and from the movement of raindrops

As useful and ubiquitous as solar energy is becoming, it still has one major Kryptonite: gloomy weather. Now, a team of Chinese engineers has developed a hybrid solar cell that can produce electricity come rain or shine, using the triboelectric effect to harvest energy from the movement of raindrops on its surface.

Triboelectric nanogenerators (TENGs) create a charge from the friction of two materials rubbing together, which you may recognize as static electricity. It could find eventual practical uses in harvesting energy from movement or vibrations through clothing, car wheels, floors, or touchscreens.

In this case, the researchers tapped into the motion of raindrops rolling off the surface of a solar cell. To do so, they added two polymer layers to form a TENG on top of a photovoltaic cell. The top layer consists of a polymer called polydimethylsiloxane (PDMS), while the lower layer is made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). To improve the performance of both layers, the polymers are first textured with grooves by imprinting them with the pattern from the data side of DVDs.

The hybrid solar cell uses layers of two polymers to harvest energy from raindrops as well, using the triboelectric effect
The hybrid solar cell uses layers of two polymers to harvest energy from raindrops as well, using the triboelectric effect

The top layer is activated when drops of water land on it and roll off, bringing the polymer into contact with the lower layer. The PEDOT:PSS film acts as a mutual electrode between the TENG and the solar cell, conducting energy from the former to the latter. To make sure the photovoltaic cell still functions when it's sunny, both polymer layers are transparent.

According to the team, the device had a peak short-circuit current of about 33 nA, and a peak open-circuit voltage of around 2.14 V. That's not particularly high, but it is enough to demonstrate that the concept works, and might be scalable.

This isn't the first time researchers have experimented with TENGs to make solar cells more useful in other weather conditions, but the team says the new device is a simpler design, less bulky and easier to manufacture than others.

The research was published in the journal ACS Nano.

Source: American Chemical Society

8 comments
Tom Lee Mullins
I think being able to get energy from rain drops would be great for when the sun isn't shining and it is raining; especially good for areas that get more rain than sunshine.
Eric the Red
0.000000066 W is very small, I wonder what size produced that and if it scales up well. This would take a lot of rain at 10% eff. probably 600,000 rain drops per second. I hope my decimal places were correct ;)
Douglas Bennett Rogers
This looks like a delicate and short lived outer layer.
darron
I had the same question as Eric the Red. What was the actual surface area of the device? Thx!
DavidRogerBrown
Another ideal that clearly shows that the future is renewable & dino juice is so yesterday. At the same time our president & politicians are cutting research & development in this most critical field while ignoring climate change. While giving huge tax breaks to carbon companies. As China & Europe race ahead. How short sighted and stupid.
ljaques
There sure is a lot being made of nano whatevers. I think they're fine for powering nano-sensors, but that's about it. Maybe a nano-photochromic window could power itself sometimes. But other than that, it seems pretty much overpowered. I'm sure that even in the darkest cloudy weather, the solar panels would outproduce the nano layer, and as Doug said, probably a short-lived outer layer. What would replacement of the layer cost in dollars, electrical losses, and time? Enough to pay for itself? I strongly doubt it. While I'm all for alt energies, shouldn't we be a bit more realistic? If these pan out, find micro niches for them to thrive, but don't downgrade solar panels on a whim. I'd really love to see the Life-cycle cost analysis (LCCA) for these. In the meantime, I have to get that KW of standard solar up.
Nik
A textured surface will collect crap! A look at most roofs will show that in a very short time, there is enough crap on a roof to support life, in the form of mosses etc. so this idea is likely to be of zero effect in a very short time, without the added costs of a cleaning system. In addition, the collected crap will reduce the efficiency of the solar panels. It may be effective in a lab, but probably utterly useless in the real world!
DavidStonier-Gibson
So even in China researches can get funding for stupidly unrealistic projects!