Molecular rectification could prove highly power efficient

The devices are based on the principle of molecular rectification, first proposed in 1974. They allow current to pass when operated at forward bias and block current when the bias is reversed. The researchers claim they have demonstrated a tenfold increase in switching efficiency by changing just one carbon atom. They add these devices could provide new ways to combat overheating in mobile phones and laptops. The device, created by Dr Damien Thompson at TNI and a team of researchers at the NUS led by Professor Chris Nijhuis, is based on molecules acting as electrical valves, or diode rectifiers. According to Dr Thompson: "These molecules are very useful because they allow current to flow through them when switched on and block current flow when switched off. The results show that simply adding one extra carbon atom is sufficient to improve the device performance by more than a factor of ten. "We are following up lots of new ideas based on these results and hope, ultimately, to create a range of new components for electronic devices." Computer simulations show molecules with an odd number of carbon atoms stand straighter than molecules with an even number of carbon atoms, allowing them to pack together more closely. When tightly packed assemblies of these molecules were formed on metal electrode surfaces by the group at NUS, they were found to be remarkably free of defects. A key enabling feature for nanoscale electronics will be the ability to use molecules as rectifiers and switches. By demonstrating the rational design of molecules that rectify current with a large and highly reproducible on/off ratio, the study provides a key advance towards the creation of technologically viable ultra small device components.