Batteries and semiconductors rely on the movement of charges from one group of atoms to another. During this process, electrons are transferred from donor atoms to acceptor atoms. Forming superatoms that can supply or accept multiple electrons while maintaining structural stability is a key requirement for creating better batteries or semiconductors, explains Professor Shiv Khanna of Virginia Commonwealth University. The ability of superatoms to effectively move charges while staying intact is attributed to how they mimic the properties of multiple groups of elements.
"We have devised a new approach in which one can synthesise such metal-based superatoms," Prof. Khanna says.
Prof. Khanna says that he and his team have theoretically proved a method of building superatoms that could result in the creation of more effective energetic materials.
Currently, alkali atoms, which form the first column of the periodic table, are optimal for donating electrons. These naturally occurring atoms require a low amount of energy to donate an electron. However, donating more than one electron requires a prohibitively high amount of energy.
The team created a process by which clusters of atoms can donate or receive multiple electrons using low levels of energy.
"The possibility of having these building blocks that can accept multiple charges or donate multiple charges would eventually have wide-ranging applications in electronics," Prof. Khanna continues.
| Above: Professor Shiv Khanna of Virginia Commonwealth University |
While such superatoms already have been made, there has never been a guiding theory for doing so effectively. Prof. Khanna and his colleagues theorise that organic ligands – molecules that bind metal atoms to protect and stabilise them – can improve the exchange of electrons without compromising energy levels.
They considered this theory using groups of aluminium clusters mixed with boron, carbon, silicon and phosphorous, paired with organic ligands. Using computational analysis, they demonstrated the cluster would use even less energy to donate an electron than francium, the strongest naturally occurring alkali electron donor.
"We could use ligands to take any cluster of atoms and turn it into either a donor or acceptor of electrons," Khanna explains. "We could form electron donors that are stronger than any element found on the periodic table."
