What sounds more innovative than ‘solar paint’? A paint that can generate electricity, but still works as normal paint? The ability to turn not only a roof, but an entire building into a solar-generating surface? If that doesn't scream innovation, then I don't know what does.
So far, the lifeblood of the solar industry has been traditional photovoltaic solar panels. Solar panels are a well-proven technology that save homeowners a ton of money. However, the hassle and expense of rooftop panel installations often deter people from switching to solar energy.
Now imagine a world where we could simply paint our roofs and walls with a type of paint that can generate electricity. I am imagining this world - and it looks very promising.
So, what is solar paint? The most important thing to know is that it isn’t a single product; currently there are three different technologies that are referred to as 'solar paint'.
The 3 types of solar paint
The idea of using a paint-like substance to generate electricity has been discussed within the scientific community for many years. Only recently have promising, real-world applications emerged.
There are three separate innovations that are classified as solar paints. Here we explore what they are and what they might mean for the future of solar energy.
#1 Solar paint Hydrogen
A team of researchers from the Royal Melbourne Institute of Technology (RMIT) have developed solar paint that generates energy from water vapor.
Put simply, the paint works by absorbing moisture from the air and using solar energy to break the water molecules into hydrogen and oxygen. The hydrogen can then be used to produce clean energy.
This is how the paint actually works: it contains a newly developed substance, synthetic molybdenum-sulphide. Absorbing moisture from the air, it works similarly to silica gel, which you’ve undoubtedly seen packaged with consumer products in order to keep them dry.
This solar paint also contains titanium oxide, a substance already present in conventional paint. The titanium oxide helps the paint use solar energy to break down the absorbed moisture into hydrogen and oxygen particles. The hydrogen can then be used to produce clean energy.
#2 Quantum dot solar cells, aka photovoltaic paint
Quantum dots, also known as photovoltaic paint, were developed at the University of Toronto. They are nanoscale semiconductors that can capture light and turn it into an electric current.
‘Colloidal quantum dot photovoltaics’ - to use the full technical term - are not only cheaper to manufacture, but are also significantly more efficient than traditional solar cells.
According to research paper author Susanna Thon, “There are two advantages to colloidal quantum dots. First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum.”
These dots could end up being up to 11% more efficient than traditional solar panels. At some point in the future, we might even be able to paint these quantum dots on our roofs and other surfaces in order to transform sunlight into electricity.
#3: Perovskite solar paint
Known alternatively as spray-on solar cells, what makes this type of solar paint possible is Perovskites.
Named after Russian mineralogist Lev Perovski, Perovskite materials are derived from a calcium titanium oxide mineral. Perovskite structure was first discovered in 1839, but it was only 10 years ago that a research team in Japan debuted the first-ever application of Perovskite for the production of solar cells.
There are many properties that make Perovskite solar cells special, but the most revolutionary is the fact that they can take liquid form, making them the perfect candidate for solar paint.
In fact, researchers have developed a way to spray liquid perovskite cells on surfaces, known as spray-on solar cells. The first-ever spray-on solar cell was developed at the University of Sheffield in 2014. A Perovskite-based mixture was sprayed onto a surface to form a sun-harnessing layer.
Out of all the new inventions that could potentially revolutionize the solar industry, Perovskite cells are possibly the most promising.