A solar cell made of organic materials has reached record efficiency in converting sunlight into electrical energy.

Organic solar cells could be cheaper and more flexible than silicon-based ones, but they are less efficient. To boost efficiency, Jianhui Hou at the Chinese Academy of Sciences in Beijing, Feng Gao at Linköping University in Sweden and their colleagues made a device by combining the polymer PBDB-T with a small molecular compound known as ITIC. The cell, measuring 1 square centimetre, had an efficiency of 10.78% under standard conditions — a record for an organic device of this size, and close to the record of 11.5% for all polymer-based devices.

Because the cell does not use large, relatively expensive molecules known as fullerenes, it could be cheaper to produce than the current best polymer-based devices.

Adv. Mater. http://doi.org/bd7p (2016)