Solar scientist honoured at UN University

An engineer from UNSW has been honoured at the United Nations University in Tokyo for her research into trapping and harvesting sunlight in thin-film silicon solar cells.

Dr Supriya Pillai, a postdoctoral researcher and fellow of the Australian Solar Institute (ASI), was runner-up for the 2012 ProSPER.Net-Scopus Young Scientist Award for Sustainable Infrastructure.

One of the key challenges and objectives in the photovoltaics industry is to create thin-film silicon solar cells that have the same energy-conversion efficiency as mainstream devices. Thinner solar cells require less material for manufacture and are therefore cheaper for consumers; however, they are less efficient at trapping sunlight, which limits their ability to generate electricity.

Pillai’s PhD and continuing research is investigating a novel and promising way of improving the performance of thin-film solar cells using plasmonics. This technology squeezes light below the wavelength limit, so it can be controlled on the nanoscale.

Her approach makes use of the unique optical properties of metal nanoparticles on the surface of thin-film solar cells, which scatter light and improve absorption.

“Conventional thick wafer-based solar cells use textures, which are features on the front to change the direction of incoming light in such a way that it can bounce back and forth and get trapped,” explained Pillai.

“However, when we talk thin films we are talking 100 times thinner cells and the textures are not feasible. Hence the metal nanoparticles are deposited on the cells as an alternative to texturing.”

Pillai is now involved with ASI projects looking at the potential of taking this technology from the labs to production, and is investigating new plasmonic structures suitable for other PV applications.

She says the most exciting thing is that the technology is not limited to improving the performance of thin-film solar cells, but can be extended to a range of other cutting-edge (third-generation) cell concepts, such as tandem solar cells, hot carrier cells and also organic solar cells.

In February 2012, Pillai outlined the challenges and potential of this technology in a commentary article published in the journal Nature Photonics. She co-authored this article with Scientia Professor and Director of the ARC Photovoltaics Centre of Excellence Martin Green.

The annual awards are sponsored by ProSPER.Net - a network of several leading higher education institutions in the Asia-Pacific region with a commitment to promoting sustainable development into their postgraduate curriculum - and Scopus, a database of peer-reviewed scientific literature.