Why transparent solar cells could replace windows in the near future

Regardless of their sustainable, ecological and clean energy sources, conventional solar panels require a large installation area and a large initial investment. Due to these limitations, it is difficult to introduce them in urban areas (especially neighborhoods with a lot of buildings or shops). But thanks to the work of ingenious engineers at the University of Michigan, that may soon not be the case.

The researchers created transparent solar panels that they believe could be used as electricity-generating windows in our homes, buildings and even our rented apartments.

Image credits: Djim Loïc / Unsplash

If these transparent panels are indeed capable of producing electricity in a cost-effective manner, the time of ordinary windows may be passing as we speak. Soon we could have access to cheap solar power no matter where we live – and to make it even better, we could get rid of these. terrible power cuts this happens every now and then because, with transparent glass solar panels, every house and skyscraper will be able to generate its own electricity independently.

An overview of transparent solar panels

In order to generate energy from sunlight, solar cells built into a solar panel are needed to absorb solar radiation. Therefore, they cannot let sunlight pass through them completely (like a glass window). So, at first, the idea of ​​transparent solar panels may seem absurd and completely illogical because a transparent panel should be unable to absorb radiation.

But that’s not necessarily the case, researchers have found. In fact, this is not the case at all.

Professor R. Lunt from MSU showing the transparent luminescent solar concentrator. Image credits: University of Michigan

The solar panels created by engineers at the University of Michigan consist of transparent luminescent solar concentrators (TLSCs). Composed of cyanine, TLSC is capable selectively absorb invisible solar radiation, including infrared and UV lights, and allow the rest of the visible rays to pass through them. In other words, these devices are transparent to the human eye (much like a window) but still absorb a fraction of sunlight which they can then convert into electricity. It’s a relatively new technology, first developed in 2013, but it is already experiencing impressive developments.

Panels equipped with TLSC can be molded into thin transparent sheets which can be later used to create windows, smartphone screens, car roofs, etc. Unlike traditional panels, transparent solar panels do not use silicone; instead, they consist of a zinc oxide layer covered with a carbon based IC-SAM layer and a fullerene layer. The IC-SAM and fullerene the layers not only increase the efficiency of the panel, but also prevent the radiation absorbing regions of solar cells from breaking down.

Surprisingly, researchers at Michigan State University (MSU) also claim that their transparent solar panels can last 30 years, which makes them more durable than most regular solar panels. Basically, you can fit your windows with these transparent solar cells and get free electricity without much hassle for decades. Not surprisingly, this prospect has a lot of people excited.

According to Professor Richard Lunt (who led the transparent solar cell experiment at MSU), “Highly transparent solar cells represent the wave of the future for new solar applications.” He adds that these devices in the future can provide similar power generation potential to rooftop solar systems and can also equip our buildings, automobiles and gadgets with self-charging capabilities.

“This is what we are working towards,” he said. “Traditional solar applications have been the subject of active research for more than five decades, but we have only been working on these highly transparent solar cells for about five years. Ultimately, this technology offers a promising path to low-cost, widespread solar adoption over small and large areas that were previously inaccessible. “

Recent developments in the field of transparent solar cell technology

In addition to the research carried out by Professor Richard Lunt and his team at MSU, other research groups and companies are working on the development of advanced solar-powered glass windows. Earlier this year, a team from ITMO University in Russia developed a less expensive method of producing transparent solar cells. Researchers have found a way to produce transparent solar panels much cheaper than ever before.

“Ordinary thin-film solar cells have a non-transparent metal back contact that allows them to trap more light. Transparent solar cells use a light permeable counter electrode. In this case, a part of the photons is inevitably lost during the passage, thus reducing the performance of the devices. In addition, producing a counter electrode with the right properties can be quite expensive, ”explains Pavel Voroshilov, researcher at the Faculty of Physics and Engineering at ITMO University.

“For our experiments, we took a solar cell made from small molecules and attached nanotubes to it. Next, we doped nanotubes using an ion grid. We also treated the transport layer, which is responsible for allowing a charge of the active layer to successfully reach the electrode. We were able to do this without vacuum chambers and working in ambient conditions. All we had to do was dribble some ionic liquid and apply slight tension in order to create the necessary properties, ”adds co-author Pavel Voroshilov.

Image credits: Kenrick Baksh / Unsplash

PHYSEE, a technology company from the Netherlands has successfully installed its solar powered “PowerWindow” in a 300 square foot area of ​​a bank building in the Netherlands. Although at present, transparent PowerWindows are not efficient enough to meet the energy needs of the entire building, PHYSEE says that with a little more effort, they will soon be able to increase the power supply. feasibility and power generation capacity of their solar windows.

The Californian company Ubiquitous Energy is also working on a “ClearView Power” system which aims to create a solar coating capable of transforming the glass used in windows into transparent solar panels. This solar coating will allow clear glass windows to absorb high-energy infrared radiation, the company claims to have achieved 9.8% efficiency with ClearView solar cells in their first tests.

In September 2021, the factory of Nippon Sheet Glass (NSG) Corporation located in the city of Chiba became the first from Japan building equipped with solar windows. The transparent solar panels installed by NSG in their facilities are developed by Ubiquitous Energy. Recently, as part of its association with Morgan Creek Ventures, Ubiquitous Energy also installed transparent solar windows on Boulder Commons II, a commercial building under construction in Colorado.

All of these exciting developments indicate that sooner or later we could also install transparent electricity-generating solar windows in our homes. Such a small change in the way we produce energy, on a global scale, could turn out to be a big step towards living in a more energy efficient world.

Not there yet

If it almost sounds too good to be true, it sort of is. The efficiency of these fully transparent solar panels is around 1%, although the technology has the potential to achieve around 10% efficiency – compared to the 15% we already have for conventional solar panels (some efficient can reach 22% or even a little higher).

The efficiency is therefore not yet fully developed to make transparent solar cells efficient, but it could get there in the not-so-distant future. In addition, the advantage of this system is that it can be deployed on a small scale, in areas where regular solar panels are not possible. They don’t have to replace regular solar panels, they just have to complement them.

Come to think of it, solar power was not considered competitive until a decade ago – and a recent report discovered that now it is the cheapest form of electricity available so far in human history. Although transparent solar cells have not yet really been used, we have seen how quickly this type of technology can develop and the prospects are there for great results.

The simple idea that we may soon be able to power our buildings through our windows shows how far we’ve come. An energy revolution is in sight, and it would be wise to take it seriously.

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