'Sandwich’ solar cells discovered

Scientists at Melbourne's Monash University have developed a new generation of solar cells that they say could lead to significant improvements in solar panel efficiency.

The team used dye sensitised solar cells containing electrolytes made out of an iron-based organometallic compound called ferrocene, also known as ‘sandwich compound’ because it sandwiches an iron atom between two organic rings to form a highly stable compound structure.

"Extensive research around the world since 1991 has improved the energy conversion efficiency of traditional iodide electrolytes to about 12 per cent,” ABC Science quoted Dr Udo Bach as saying.

"But in just 2 years of work, a single PhD student at Monash was able to achieve energy conversion efficiencies of 7.5 per cent using ferrocene compound electrolytes."

Silicon based solar cells achieve energy conversion efficiencies of 20 per cent.

However, these cells have limitations because of their complex chemistry and corrosive nature. They overcame this problem by constructing the cells in an environment filled with an inert gas.

Another problem, ferrocene’s strong charge recombination effect, which causes charge carriers generated through photon conversion to recombine before their energy can be collected, was also taken care of.

"We included additives to cut down recombination, customized the semi conductor layer and used an organic dye with stronger light absorbing properties, developed by researchers at the University of Melbourne," he said.

Future research by the team will focus on improving the system to fine tune the electrochemical properties, slightly modify the chemical structure and evaluate the stability of the ferrocene based solar cell.

According to Dr Ashraf Uddin from the University of New South Wales School of Photovoltaic and Renewable Energy, the team has to still know more about the product's reliability, the sort of durability or life span the cells are likely to have.

Uddin said these types of solar cells could do more than recharge cell phones and laptop computers.

"They could be included in the body work of cars or on the walls of buildings to help generate electricity."

Their research is published today in the journal Nature Chemistry.