Fullerene-free polymer solar cells exhibiting great efficiency and stability have been invented

Polymer solar cells can now be even cheaper and more reliable thanks to this new breakthrough

Polymer solar cells can now be even cheaper and more reliable thanks to this new breakthrough

Polymer solar cells are gaining ground lately as a low-cost alternative to their silicon counterparts. They are also lightweight, flexible, customizable on the molecular level and have the potential to exhibit transparency, suggesting applications in windows, walls, flexible electronics, etc. However, fullerenes –which are costly and unstable - are usually required in polymer solar cells in order to obtain high efficiency.

A group of chemists, led by Professor Jianhui Hou at the Chinese Academy of Sciences (CAS), has developed a unique combination of a polymer called PBDB-T and a small molecule called ITIC without the use of fullerenes. With this combination, the sun's energy is converted with an outstanding efficiency of 11%, in comparison to other polymer cells with fullerenes.

Another group at Linköping University, held by researchers Feng Gao, Olle Inganäs and Deping Qian, has characterized the loss spectroscopy of photovoltage (Voc), a key figure for solar cells, and proposed approaches to further improving the device performance. ‘We have demonstrated that it is possible to achieve high efficiency without using fullerene, and that such solar cells are also highly stable to heat. Because they work under constant solar radiation, good thermal stability is very important’, says Feng Gao, physicist at the Department of Physics, Chemistry and Biology, Linköping University. ‘The combination of high efficiency and good thermal stability suggests that polymer solar cells, which can be easily manufactured using low-cost roll-to-roll printing technology, now come a step closer to commercialization’, he continues.

The results of these two research groups are presented in the journal Advanced Materials.

Image: Researchers Olle Inganäs and Shimelis Admassie demonstrate solar cells on a roll.

Source: Sciencedaily