More Efficient Solar Panels, Thanks To Eye Of Moth And Leaf Of Lotus

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When scientists at the Oak Ridge National Lab went rifling through nature’s drawers on their hunt for a more efficient solar panel, they missed the eye of newt, but they did find inspiration in a couple of other natural ingredients, the moth’s eye and lotus leaf. The result is a “revolutionary” souped-up superhydrophobic coating that could mean an increase in solar conversion efficiency in the range of three to six percent.

That may not sound all that awesome, but the new solar panel coating hits the trifecta when you count in brownie points for two other factors that contribute to the overall cost of solar energy, which would be manufacturing costs, and maintenance and operating costs.

efficient solar panel

Group Hug For More Efficient Solar Panels

Oak Ridge is part of the Energy Department’s network of national laboratories, so let’s pause here while US taxpayers get a nice group hug for chipping into the research project.

You can get all the details about the new coating in the Royal Society of Chemistry’s Journal of Materials Chemistry C under the impressive title “Monolithic graded-refractive-index glass-based antireflective coatings: broadband/omnidirectional light harvesting and self-cleaning characteristics,” but for those of you on the go it all boils down to a specialized, ultra-thin layer of porous glass.

Here is a snippet from the abstract:

…The coatings comprise an interconnected network of nanoscale pores surrounded by a nanostructured silica framework. These structures result from a novel fabrication method that utilizes metastable spinodal phase separation in glass-based materials….the fabricated nanostructured surfaces are found to promote a general and an invaluable [similar]3–7% relative increase in current output of multiple direct/indirect bandgap photovoltaic cells.

As a side note, the Energy Department’s press materials have the upper range at six percent, not seven, so we’ll settle for that.


The boost in solar panel efficiency is enabled by the antireflective property of the coating. It can also be tweaked to make it superhydrophobic (that’s fancyspeak for impressively water repellant) and resistant to fog. Did we mention that the new coating is extremely durable, too?

…Moreover, these antireflective surfaces also demonstrate superior resistance against mechanical wear and abrasion. Unlike conventional counterparts, the present antireflective coatings are essentially monolithic, enabling simultaneous realization of graded index anti-reflectivity, self-cleaning capability, and mechanical stability within the same surface…

The Biomimicry Road To More Efficient Solar Panels

In case you’re wondering where the witches’ brew of inspiration comes in, the lotus leaves are the easy part: they repel water like gangbusters, using rain for self-cleaning.

The trick for superhydrophobicicity is to get the surface angled so that drops of water hit at an angle of about 150 degrees. Oak Ridge came thisclose, in the range of 155-165. At that angle, water “literally bounces off, carrying away dirt and dust.”

The thing about the moth’s eye is a bit more complicated. Here’s the Oak Ridge team leader waxing enthusiastic on the topic:

…a moth’s eyes are antireflective because of naturally covered tapered nanostructures where the refractive index gradually increases as light travels to the moth’s cornea…

Here’s how it translates into modern fabrication methods that produce precisely engineered nanoscale structures (from the abstract):

These structures result from a novel fabrication method that utilizes metastable spinodal phase separation in glass-based materials. The approach not only enables design of surface microstructures with graded-index antireflection characteristics, where the surface reflection is suppressed through optical impedance matching between interfaces, but also facilitates self-cleaning ability through modification of the surface chemistry.

If you caught that thing about meastable spinodal phase separation, that produces a highly durable, heat-resistant surface. In contrast, conventional coatings are fabricated from powders or polymers, which tends to make them more fragile.

We’ve been focusing on the benefits in terms of more efficient solar panels, but the research team also sees a whole slew of applications in other fields aside from photovoltaics, including all sorts of optical instruments and light sensors.

They’re also looking at applying the coating to ships’ hulls, to prevent biofouling (that refers to buildup of barnacles and other sea creatures, which erodes fuel efficiency).

One Down, One To Go

Here in the US, coal power plants are shutting down like ninepins, and though it would be nice to give competition from solar power the credit, to a great extent the availability of low cost natural gas is factoring into the demise of coal.

So, are we going to be stuck with natural gas forever? Not necessarily.

Low-cost gas appears to be on its way out. If the busted natural gas drilling boom leads into yet another cycle of rising prices, it will be helped along by two new factors emerging in the US: the export of more natural gas under the Obama Administration (though see here and here and here for some important caveats) and the use of more natural gas in domestic plastics production.

Meanwhile the installed cost of solar power is already spiraling downward, and Oak Ridge’s new coating for low-maintenance, more efficient solar panels is a good indication that solar costs will continue to sink like a stone.

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Image Credit (cropped): Courtesy of Oak Ridge National Laboratory.

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Tina Casey

Tina specializes in advanced energy technology, military sustainability, emerging materials, biofuels, ESG and related policy and political matters. Views expressed are her own. Follow her on LinkedIn, Threads, or Bluesky.

Tina Casey has 3140 posts and counting. See all posts by Tina Casey

16 thoughts on “More Efficient Solar Panels, Thanks To Eye Of Moth And Leaf Of Lotus

  • “Eye of newt, and toe of frog,
    Wool of bat, and tongue of dog,
    Adder’s fork, and blind-worm’s sting,
    Lizard’s leg, and howlet’s wing,–
    For a charm of powerful trouble,
    Like a hell-broth boil and bubble.”

    Why the very idea of solar moths and lotus falls
    trippingly from the tongue.

  • The conversion efficiency of solar panels is SFIK conventionally measured for perpendicular illumination, the off-axis performance being modelled rather than measured. Here we have an innovation that looks as if it primarily improves off-axis performance. What indicator are they using?

  • I had to read this twice to get it but it looks pretty impressive. Changing the refractive index as the light travels through could make amazing telescopes, microscopes, glasses besides PVs.

    Ain’t science grand?!

  • Wonder if it’ll lengthen or shorten the laminates lifespan. I’m optimistic though.

    • My monocrystalline Arco Solar panels bought in 1980 (53 Watt) still work like new, with NO LOSS at all. And yes, they have been mounted in 1980 and never moved from their spot. Functioning all-year round, in a rather harsh climate (very hot in summer, very cold in winter).

      • That’s amazing! I’m trying to talk my parents into getting solar. They are in Florida and have a HUGE metal roof. Their electric bill is between $250/380 a month.

        • If they get it, opt for a hybrid inverter that let’s them use the energy in a blackout and has the option to add a battery later..

          • funny you say that, It was the tesla wall battery pack that finally got them interested in solar … My dad did some basic estimates and thinks he can pay the battery pack off (when he gets it) in 4-5 years (7.5k$Pack/interfere/labor) due to how expensive his rates are with Fort Pierce Utilities. Fl Power And Light, which has better rates, would take a little longer to pay itself off. I sent them links to get quotes from a few companies. Hopefully they will move forward with their solar roof. Hopefully the solar quotes he gets are reasonable. Not sure what the rates are like in south Florida.

          • You can only use the energy during a blackout when you have batteries.

          • If the load is less than the pv output you don’t need batteries.. our hybrid inverters just shut down the load if it exceeds the solar power available, no batteries.

            But you’re right.. if clouds pass over etc you want some battery buffer to go with that or to be able to start a motor (water pump or some such).
            But believe me, even a little bit of power if there is none from the grid does wonders (recharging a mobile phone, having the fridge run, etc)..

          • Don’t spam us, bro….

          • No way dude, im not going to make you rich with a BS line….but ill save you money with a cool solar system

          • Nathan, I appreciate your enthusiasm, but you’ve received your one spam warning….

          • How do you figure i am spamming anything? I simply wanted to help a guy out. Spam, i believe, is not even a real person. It is a computer bot, which i assure you i am not. So get out of here with your ridiculous warnings

          • I understand that you are attempting to help someone out. But you are also advertising your product/services. We don’t entertain free advertising, even if it is for renewable energy products/services.

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