Next-generation solar cells: Graphene is the answer

Singapore 17 June 2013. Longer-lasting and better - next-generation solar cells and optoelectronic devices will tout these properties and more when created from a combination of graphene and other one-atom thick materials. By Mallika Naguran.

A group of scientists from the University of Manchester and NUS recently published the results of their breakthrough work in Science. It could lead to a whole new type of solar device in years to come.

A high tech graphene "sandwich" has the potential to revolutionise photovoltaic devicesGraphene is the world's thinnest, strongest and most conductive material, and its isolation also led to the discovery of a whole new family of one-atom-thick materials. By stacking up the atom-thick materials and sandwiching them between two layers of graphene, multilayered heterostructures with multifunctional properties are formed. These features range from conductive to insulating, as well as opaque to transparent. 

The team managed to identify the ideal combination of materials - new photosensitive class of two-dimensional materials called transition metal dichalcogenides (TMDC) with optically transparent and conducive graphene - which collectively create a very efficient photovoltaic device, pointed out Professor Antonio Castro Neto, Director of the Graphene Research Centre at NUS and corresponding author of the paper. 

"It was impressive how quickly we passed from the idea of such photosensitive heterostructures to the working device. It worked practically from the very beginning and even the most unoptimised structures showed very respectable characteristics," said Dr Liam Britnell of the University of Manchester, the lead author and a visiting scientist at the Graphene Research Centre. 

Scientists evaluate single-layer graphene images at the NUS Graphene research laboratoryThe new devices could potentially be employed as ultrasensitive photodetectors or very efficient solar cells, giving rise to tantalising scenarios. For instance, self-sufficient buildings that tap electric energy generated by sunlight absorbed by their walls; and energy that can be used flexibly to alter the transparency and reflectivity of fixtures and windows in response to environmental conditions such as temperature and brightness.

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