FIDO tech boosts stability of perovskite solar cells

Researchers at Nagoya University in Japan have created a material based on fullerene indanones (FIDO) that could improve the durability of next-generation solar cells. The researchers published their findings in the ­Journal of the American Chemical Society.

The next-generation of solar cells will potentially use perovskite-based cells. These crystal-based cells are efficient and can even generate electricity indoors under weak light conditions. They are also lighter and more flexible than conventional silicon solar cells and are therefore suitable for installation on vertical surfaces, such as windows and walls.

Many of the unique properties of these solar cells come from fullerene (C60). Shaped like soccer balls, fullerenes are carbon-based semiconductors that can channel electrons to create power, making them essential for organic electronics. Researchers can attach organic molecules to fullerenes to enhance their electronic function, thereby creating derivatives with different properties. The researchers, led by Professor Yutaka Matsuo, added indanone to fullerene to create FIDOs.

Indanone is a useful compound in reactions and has a unique structure of fused rings that create strong carbon links between the fullerene and the benzene part of the indanone. This creates an arrangement with excellent stability even when heated. Using FIDO, the researchers controlled the film to create an amorphous material instead of the more common crystalline material found in silicon solar cells. Amorphous materials have a more random structure than carefully organised crystals; this allows amorphous films to be engineered to have specific properties by adjusting the deposition conditions and tailoring the electrical characteristics of the film to meet the requirements of solar cell technology.

When compared with a standard film, the researchers found that the new film was more efficient and stable; these properties also did not degrade. There was also no decrease in conversion efficiency. Matsuo said the amorphous film did not crystallise upon heating and showed excellent morphological stability.

“A problem with films is that when heated to 150°C, the degree of crystallisation increases. Our newly developed film is an amorphous thin film after deposition and remains amorphous even when heated,” Matsuo said.

This new technique could have a range of applications, as the fullerene derivatives can be used for perovskite solar cells and for photoelectric conversion elements, such as organic photodiodes and organic photodetectors. “Organic photodetectors contribute to the high resolution of imaging sensors in cameras and will be used in fingerprint authentication on smartphone displays, allowing unlocking from any part of the screen touched by a finger,” Matsuo said.

Image credit: iStock.com/deyanarobova