Visions for a molecular future

Abstract

At two recent conferences on molecular electronics, held in the past 12 months, there were feelings that the field would by now be a mature technology that would soon result in applications, when in fact it is not. I like to compare the current status of molecular electronics with what happened to microelectronics: the concept of the transistor had already been well established when finally the complementary metal–oxide–semiconductor technology arrived with its disruptive power. In between, plenty of unexpected new physics had been developed and inspired solid-state physicists to look far beyond mere applications in electronic devices. I see molecular electronics being in a similar exploratory phase. The proposition to use molecules as functional building blocks can be considered rather old by now, with experimental molecular electronics starting over 15 years ago. After having put a lot of effort into the fabrication of electronic devices and gaining basic understanding of the electronic conduction mechanisms, researchers are now starting to look beyond electric-charge transport and focus on molecular-transport properties, for example, thermoelectric and spin transport. Although interfacing molecules with metallic leads has proven to be a major challenge, molecular electronics remains a fascinating playground for scientists for exploring new fundamental concepts and it will hopefully stay in this 'hunter-gatherer' phase for many more years. Meanwhile, the first technological achievements may come from the development of molecule–semiconductor hybrid structures, and perhaps from molecular spintronics.