When we think of solar panels the first image that comes to mind is pieces of land filled with dark blue solar panels or perhaps unsightly rooftops that stand out because of the panels. However, this image might be about to change in the not-too-distant future. Research about color-neutral transparent solar cells that do not generate visual pollution reached a new record at the end of last year.

For several years researchers at the University of Michigan (US) have been working on a prototype of transparent solar cells. The technology was first introduced to the scientific community in 2014, and six years after this milestone in 2020 a new and improved technology was announced: a combination of organic molecules replaced the conventional silicon as the main component. The new carbon-based design improved absorption of the light spectrum, which resulted in a new efficiency record.

Transparent solar cells are measured by their light utilization efficiency, which describes how much of the solar rays captured by a photovoltaic module can be harnessed and converted into electrical energy. With this new design 8 % of all solar rays captured can be harnessed and converted. To put this number into context, previous transparent solar cells have light utilization efficiencies of about 2-3 %. When it comes to conventional solar panels, the average efficiency is about three times as much as with transparent ones.

In addition to improved efficiency, the change in the design also made it possible to achieve up to 43 % of transparency in the cells. This improvement could make transparent panels a possible replacement for traditional glass windows on buildings or cars, making them power sources in addition to their basic function. It would be possible to take advantage of the extensive direct sun exposion to cover partially or perhaps even fully a building’s or car’s electricity needs.

“Although the transparent solar panel technology is still in development, its tremendous potential makes it worth following in the near future.”

While a light utilization efficiency of 8 % might not sound too impressive when compared with conventional solar panels, the results could be significant if the lower efficiency is compensated with large scale deployment. If the technology were to be applied on a global scale with most windows in a home or office building consisting of clear solar panels, the effects could be transformative. For example, preliminary estimations show that transparent solar cells could cover 40 % of the energy demand in the United States.

Although the transparent solar cell technology is still experimental and under development, its tremendous potential makes it worth following in the near future. It could offer an eco-friendly power source that could be applied on buildings and road infrastructure on a large scale. This innovation would also mean that solar energy would no longer require extensive land parcels or unsightly roof spaces as in the case of conventional solar panels. Time will tell how close we are to converting buildings, skyscrapers and cars into power sources.



Michigan News, 08/2020. Transparent solar panels for windows hit record 8% efficiency.
Solar Magazine, 02/2020. Transparent Solar Panels: Reforming Future Energy Supply.



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