Solar panels are an incredible innovation in energy tech, but they’re way less efficient
than they could be, because they have a problem: heat.
Specifically, waste heat, or energy that’s lost while converting the sun’s energy into
electricity.
But a new technology—made possible by carbon nanotubes—may be just the thing that brings
solar panels into the lead for energy technologies.
Which would be sweet.
In brief, a solar panel works like this: the solar cell is made of a semiconducting material,
like silicon, that’s had some other, differently-charged elements added to create an internal electric
field.
When photons from the sun bounce down and hit the solar panel, they knock electrons
off the silicon atoms, and those electrons can then be pulled into an external circuit
as electricity.
So there ya go, sunshine into power.
But not all of the sun’s rays that touch a solar panel get turned into electricity,
and this is because not all light is created equal.
Electromagnetic radiation, of which visible light is a part, is a spectrum of many different
wavelengths, and only certain-wavelength photons carry the right amount of energy to knock
electrons loose.
For the rest of the wavelengths that can’t displace electrons, that energy is lost, unable
to be used in a solar panel to generate electricity.
We can actually lose about 70% of the electromagnetic radiation that hits a solar cell because of
this mismatch in energy levels!
This is one of the biggest issues facing solar panel efficiency.
And this, paired with other long-standing problems—like the resistance that electrons
face when passing through conducting materials—makes scientists think that in the future, even
with improvements to the existing tech, we’re looking at a maximum,
peak efficiency of solar panels at 29%.
Which still seems pretty low, to be honest.
I mean come on, sunlight is free—surely something can be done about this.
Well, one rescuer comes in a surprisingly tiny package.
Researchers at Rice University are adding a film of carbon nanotubes.
When looking at why solar panels lose so much energy, the researchers behind this new tech
saw that the radiation from the sun that couldn’t be absorbed by the solar panels was bouncing
off as heat… and they wanted to harness it.
But how to turn that heat into electricity?
Thermal radiation, like the kind released by solar cells is broadband— which is kinda messy.
Converting sunlight into electricity is only efficient if the emissions are in a pretty
narrow band, nice and precise.
So the researchers created wafer-thin films of carbon nanotubes that can absorb that broadband
waste heat and channel it into narrow bandwidth photons that can be easily converted to electricity.
So instead of going from heat to electricity, the nanotube film makes the conversion process
more efficient by taking that energy from heat to light to electricity.
Nanotube film is a perfect material for this because it can withstand temperatures up to
1,700 degrees Celsius, so it’s not going to buckle under the heat.
And this is huge.
It doesn’t require a change to the fundamental makeup of solar panels, so its minimally disruptive
to existing solar infrastructure.
And the researchers say that their tech could theoretically increase the efficiency of solar
panels from that measly 29% efficiency maximum....all the way up to 80%.
We live in a world where we’re gravitating more and more towards renewable energy, and
we NEED to.
But solar energy, this hugely untapped energetic resource, currently only produces around 2%
of the world’s electricity.
Potentially huge leaps in solar panel efficiency could make so much more of the sun’s energy
available for use.
The project is still in the prototyping phase and is a ways out from being used in existing
technologies, but if its promises come to fruition... it could change the way we think
about the future of our energy grid, and how efficiently we can power the world with clean energy.
Big news.
If you want even more on how solar panels are adapting into the future, check out this video
over here on solar cells powered by bacteria.
And subscribe to Seeker for energy tech updates as they break.
Let us know what other energy developments you’d like to see us cover down in the comments
below and as always, thanks for watching.