Professor Atsushi Nakajima, Project Associate Professor Masahiro Shibuta (at the time of research; currently Associate Professor at Osaka City University), and Assistant Professor Tomoya Inoue et al., have succeeded in fabricating aluminum (Al) superatom substrates by size-selectively depositing Al nanoclusters which were synthesized in the gas phase on an organic substrate pre-decorated with organic molecules, revealing that Al 13-mer superatoms were fixed to the surfaces in a negative ion state.
In order to overcome global environmental problems, it is crucial that a functional nanostructured substrate is developed to facilitate more efficient processes for chemical and energy conversion. Nanocluster superatoms are novel functional nanoscale units which are composed of several to several tens of atoms because nanocluster superatoms exhibit novel physical and chemical properties based on discrete electronic states mimicking that of an atom. However, there had been an intrinsic problem that nanocluster superatoms could not be stabilized on substrates owing to geometric deformations and the change in charge states through a nanocluster-substrate interaction, along with a methodological issue for the synthetic difficulty of efficient generation of nanocluster superatoms.
In this research, anionic Al 13-mer superatoms of Al13− were synthesized abundantly in a gas phase and the Al13− superatoms were fixed onto a substrate orderly using the organic substrates pre-decorated by organic molecules such as C60. In general, nanoscale aluminum-based materials exhibit extreme chemical reactivity and are instantly oxidized. However, the research group found that the oxidation reactivity rates of Al-superatom substrates could be reduced by about two digits by fabricating ordered assembled-films of Al13− superatoms. The results can be regarded highly useful in terms of developing functional nanostructured substrates with Al13− superatoms, leading to the creation of nanostructured functionalities toward the next generation chemical and energy conversions.
The results of this research were published in the academic journal "Nature Communication" on March 14, 2022.