The path to lightweight solar power

An international collaboration is leading the way to lightweight, flexible solar cells suitable for wearable solar power.

Single layer graphene sheet on PET substrate. Credit to: Hellen Jin.

Transparent conductive electrodes (TCEs) are essential components of optoelectronic devices such as LEDs, LCDs, touchscreens and solar cells. TCEs are typically comprised of an indium tin oxide (ITO) film. However, due to the increasing scarcity of indium, the search for an alternative earth-abundant-element based TCEs has become an important endeavour in optoelectronics research.

A team at the Centre for Organic Photonics & Electronics (COPE) supported by the Australian Centre for Advanced Photovoltaics has taken this opportunity to develop an alternative TCE that approaches the performance of ITO.

“Because of the brittleness and lack of mechanical flexibility of ITO, ITO is not the TCE of choice for manufacturing low-cost flexible organic solar cells,” said Dr Hellen Jin, lead COPE author of this research. “Graphene TCEs are a promising alternative to ITO as they are flexible, robust, conductive and transparent. Our research has pursued its application in organic solar cells and found its potential for lightweight and flexible solar power.”

Together with colleagues at the Chinese Academy of Sciences’ Shenyang National Laboratory for Materials Science, the team has developed graphene sheet-based TCEs that can be flexible, made from inexpensive and abundant carbon sources, and used for organic solar cells.

“Combining the graphene expertise at the Chinese Academy of Sciences with the advanced knowledge and skills of COPE in organic photovoltaics, and the support of comprehensive measurement techniques of ANFF-Q, has enabled the project to achieve tremendous outcomes from the project,” said Hellen.

“Our results provide the first steps in a pathway to solving the common problems associated with the large surface roughness, low work function and high cost of graphene TCEs, as well as the brittleness of ITO. Our aim is to develop the application of graphene TCEs in organic solar cells and open the opportunity for its industrialisation in flexible and potentially wearable solar power.”