Shining a Light on Eco-Friendly Solar Paint

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Nearly 70 years after the first solar panel was developed at Bell Laboratories in New Jersey, scientists are creating a new solar energy product the original innovators might not have thought possible: solar paint.

Solar paint produces an electrical charge using the sun’s energy, just like conventional panels do. Made from photovoltaic nanoparticles suspended in a solvent, it can be applied to metal surfaces, such as roofing tiles, or printed as a thin film.

Although the technology is still under development, scientists are already considering it to be a lighter, easier to transport, and potentially cheaper alternative to solar panels. Researchers at the National Renewable Energy Laboratory believe it can be mass-produced and sold in paint cans at hardware stores nationwide, allowing homeowners to install the solar-energy system themselves.

Solar paint is a step up from solar panels, which are still relatively expensive for the average American homeowner and often require technical expertise to install, despite having dropped by 89% in price since 2010.

In this article, we explore what solar paint is, and the benefits that it could bring to you. 

What is solar paint?

Solar paint is a liquid-based solar technology that uses light-absorbing nanomaterials to produce electricity.

In development since the mid-2000s, solar paint is quickly becoming as efficient as traditional solar panels. Current research suggests that perovskite-based solar paint has an estimated efficiency of about 19 percent – above the 10 percent efficiency required for solar technologies to be viable for commercial use. 

At 19 percent efficiency, it can absorb nearly one-fifth of the energy from the sun. It trails closely behind traditional silicon-based solar panels, which have an efficiency of about 25 percent.

Additionally, it can be sprayed or painted onto surfaces to create a thin sheet of photovoltaic material. When the paint dries, it leaves behind a thin, flexible coating of energy-generating solar nanocrystals that can be linked up to a building’s electrical system.

The thin photovoltaic sheet is expected to be more weather-resistant than conventional solar panels. It may also provide better protection and durability during snowstorms and hail. Researchers, like the team at Australia’s University of Newcastle, hope that once solar paint hits the market, it can serve a double function as roof shingles and energy generator. 

But before that happens, more research needs to be done to speed up the manufacturing process of the paint. Solar paint currently takes so long to dry that clumps occur at different parts of the film, reducing the film’s overall efficiency. 

Thankfully, a team of researchers at the Korea Institute of Science and Technology (KIST) are already developing a spin-coating technique for solar paint that speeds up the paint evaporation process and spreads it evenly over a large area. The process has so far shown a 30 percent improvement in the power-conversion performance of solar paint when compared to existing technologies.  

What is it made of?

Solar paint is made from tiny semiconductors suspended in a solvent. These semiconductors convert sunlight to electricity and can be produced from a variety of organic and inorganic materials.

At the present moment, semiconductors in the form of photovoltaic quantum dots, molybdenum disulfide, and perovskite minerals are used to manufacture the paint. 

For researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the University of Toronto, photovoltaic quantum dots made from lead sulfide are the semiconductor of choice. They’re said to be cheaper to manufacture than other nanoscale semiconductors and more efficient than silicon-based solar cells.

Photovoltaic quantum dots allow researchers to modify separate batches of solar paint to meet local light and weather conditions. The size of the quantum dots can be made larger or smaller to increase the amount of light they can absorb.  

The dots are mixed together with gold nanoshells before being immersed in a solvent to increase their efficiency, which currently stands at about 12.9 percent. With more research, scientists predict that quantum dot solar paint could become 11 percent more efficient than traditional solar panels. 

For researchers in Japan and the University of Sheffield, perovskite materials, derived from calcium titanium oxide, are showing promise that they could be scaled to high volume manufacturing. These materials require less energy and equipment to make than other photovoltaic cells and work quite well with absorber materials to achieve high levels of efficiency.

They can be combined with materials such as crystalline silicon to create solar paint that captures energy well in low-light conditions. 

Other researchers at the University of Kansas are exploring the potential of molybdenum disulfide, which creates “free” electrons that bounce around vigorously when exposed to sunlight.  

How much does it cost?

Although solar paint is not yet available for purchase, researchers estimate that it will cost just a fraction of traditional solar panels.

That’s mainly because solar paint doesn’t require expensive machinery to produce. The semiconductor nanoparticles simply need to be mixed with other absorber materials and immersed in a solvent.  

According to Professor Paul Dastoor at the University of Newcastle, a solar paint-based home energy installation could cost just one-tenth of a silicon solar panel installation. Though he didn’t specify what a can might cost, he suggested that a sheet-printed film version of it could be commercially available at 7 Australian dollars per square meter.

This sentiment is echoed by the NREL, who also believes that solar paint can be available at low prices. Researchers there are still studying whether the paint should be sold as a liquid or a dried film to ensure maximum efficiency for homeowners. 

Can you paint over solar panels?

Discussions about an upcoming solar paint product should not be confused with the act of painting over existing panels. 

Solar panels are an existing, standalone technology that does not require any additional painting or coating. The majority of panels available today already have a special coating over them to make the panels anti-reflective in sunlight and weather-resistant. 

Any type of paint damage caused to solar panels by spray paint, roof paint, or wall paint can drastically reduce their efficiency by more than 50 percent. The damage may even void the warranty on them. The chemicals in the paint may corrode the panel’s coating and in some cases the cells. 

Most paint damage to panels occurs during roof repair and paint works. If you’re planning to do either of these, it’s best to cover up your solar panels to protect them from overspray and accidents. Removing paint from solar panels usually requires a lengthy cleaning process involving clay blocks and deionized cleaning treatments.

The future of solar paint

Thanks to recent advancements in energy efficiency and manufacturing, solar paint already has an efficiency rate of about 20 percent. Together with its low price tag and use of commonly available materials, solar paint could become the world’s cheapest solar technology.

Here are three ways that it could revolutionize our planet:

Help us reach net-zero emissions

Energy from the sun is a key weapon in the fight against climate change. To reach global net-zero carbon emissions by 2050, cities and rural communities around the planet will need to phase out fossil fuels and rely on alternative and clean sources of energy, of which electricity generated by solar paint could be one.

The paint’s low cost will make homeowners more interested in switching to solar energy. Plus, its compact size and ruggedness will allow it to reach communities everywhere, helping to reduce energy poverty.

Make home solar energy power systems DIY

Also, solar paint may become so widespread and easy to use that installing a solar paint home energy system could be done by homeowners themselves

Instead of buying bulky panels that require specialized expertise to install, homeowners may be able to apply the paint on their roofs or walls themselves. It could be as simple as spraying a metallic contact layer onto the roof or wall, waiting for it to dry, and then applying the paint. Scientists at NREL predict that a solar paint-based home power system may be able to last up to 15 years.

Potentially boost space exploration

Solar paint may even replace the solar cells currently being used to power space vessels and probes.

Researchers believe that quantum dot solar paints paired with cheap thin-film perovskite materials can achieve the same level of efficiency as silicon-based solar panels. The materials are more lightweight and cheaper to manufacture and could open up many new possibilities for space vessel design.

Other ways to fight climate change

Installing a home solar electric system is a great way to fight climate change but it’s not the only one. You can also buy personal carbon offsets and cut your support for fossil fuel companies; both of which can help accelerate our transition to a carbon-neutral planet.

If you want to get started, Aspiration can help you. Aspiration is a B Corp certified online finance platform that helps customers buy carbon offsets automatically through our app. Our Plant Your Change program rounds up every transaction you make to the nearest dollar and uses the spare change to plant trees on your behalf. 

Plus, the money you save with us is safe from fossil fuels. We don’t invest any money in oil companies or any environmentally-destructive industry for that matter. We make sure that your wealth multiplies as you do your part to make the planet a better place.

*Photo by Zachary Keimig on Unsplash

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