The team, led by chemists James Heath, J. Fraser Stoddart and postdoctoral scholar Pat Collier, recently overcame a major hurdle to the creation of molecular computers, which promise to be cheaper, smaller and more efficient than today's silicon-based computers.
"Last year, we published an architectural demonstration with molecules and demonstrated that it is possible to do simple mathematical operations," Heath said. The paper, published in Science, received worldwide attention. "How- ever, the switches used in that work switched only once, and this limited their relevance to any serious technology.
"Now we have taken another class of Fraser's molecules and demonstrated that they may be repeatedly switched on and off over reasonably long periods of time in a solid-state device under normal laboratory conditions. For the first time, we are able to turn the molecular switches on and off repeatedly."
With this critical step, the researchers are now on the way to developing molecular RAM (random access memory), a major challenge that must be met if this is to be a viable technology, Heath said.
"From here, molecular RAM may well be just a matter of time. While there are many pitfalls between the demonstration of a technology and the actual invention, at the moment we can't see how any of those pitfalls could prove fatal."
Overall, the pace of progress has been faster than the researchers had initially expected.
"When I joined UCLA's faculty three years ago, if someone had asked me how far off molecular computing was, I would have said on a scale of a quarter-of-a-century," said Stoddart. Before coming to UCLA from England's University of Birmingham, he tried unsuccessfully to interest other scientists in working on a molecular computer in Europe. "Things I was only dreaming of are suddenly becoming a reality in Jim's lab," Stoddart said.