The science behind transparent solar panels

Have you ever thought about transparent solar panels ? To generate electricity from windows, for example ? To shift cities from major energy users to energy providers ? This technology is called photovoltaic glass and scientists are currently trying to enhance its efficiency. The more transparent the panel is, the less efficient it is.

Two scientific studies published last July 2022 provided great developments in this area, one from University of Michigan in US, focusing on organic solar panels and the other from the Tohoku University in Japan, testing new materials and techniques.

On July 13, 2022, the group of researchers from University of Michigan led by Stephen Forrest released their study, reporting efficiently scaling semitransparent organic solar cells to two meters by two meters. Traditional silicon-based solar cells are completely opaque while organic solar cells, a kind of plastic, can be transparent. Compared to silicon-based solar panels, organic solar cells have lower efficiency and short lifespans, but this recent work has achieved record efficiencies of 10% and estimated lifetimes of up to 30 years. 

The press release from the University is here and the paper “Multilevel peel-off patterning of a prototype semitransparent organic photovoltaic module” is available here (subscription).

A few days earlier, on July 4, 2022, a group of scientists led by Toshiaki Kato from the Tohoku University, reported on innovative design works by exploiting complex interactions between ultra-thin materials. Technically speaking, to make the solar cell, the team controlled the contact barriers between indium tin oxide (ITO), one of the most widely used transparent conducting oxides, and a monolayer tungsten disulfide. Then tested layers of serval different materials. The design has allowed not only to obtain a solar cell almost invisible to the naked eye but also to increase by more than 1,000 times the conversion efficiency compared to a similar device. The group also studied manufacturing on a large scale, creating a small cell of 1 cm2, with a power of 420 PW and a very average transmission value of visible light of 79%. With this size, it would be used to power smaller devices, like cellphones.

Click here for the Press Release from Tohoku University while the research “Fabrication of near-invisible solar cell with monolayer WS2” as published in the journal Scientific Reports is available by clicking on the image below.