Endohedral Fullerenes [내포풀러렌]
◦ Endohedral fullerene, which was discovered by Prof Smalley, the Nobel laureate in 1985, has a unique structure of a guest species, such as atoms or ions, being enclosed by a fullerene cage.
◦ When the endohedral fullerenes (or endofullerenes) are used as qubits, the carbon shell offers protection of the inside spin carriers from the environment, which prolongs the quantum coherence behaviour and enhances the chemical stability. In addition, the encapsulated system isolates a single qubit molecule in a fixed position allowing special manoeuvrability and facile manipulation that other materials cannot mimic.
◦ As a preeminent researcher with the unique capability to synthesise endohedral fullerene, Prof IL Jeon has blazed a trail in the device application of endohedral fullerenes, with particular emphasis on perovskite photovoltaics. His pioneering work, which introduced the application of Li@C60 to perovskite solar cells, was recognised in Angewandte Chemie as a VIP paper. This ground-breaking research not only presented the first instance of Li@C60 usage in solar cell applications, but it also unearthed a novel reaction pathway of Li@C60. Subsequent research, published in Journal of the American Chemical Society (JACS) a year later, married carbon nanotube technology with Li@C60. While this work mirrored the methodological approach of its predecessor, it revealed a more intricate reaction mechanism, thereby enriching the chemical comprehension of Li@C60. Concurrently, his team also demonstrated the doping of C60by Li@C60.
◦ His team are currently delving into the diverse varieties of endohedral fullerenes, investigating their potential applications in fields such as battery technology, quantum computing, and optoelectronics.
Carbon Encapsulated Metal Nanoparticles [탄소캡슐화된 금속나노파티클]
To date, there are two known types of carbon-encapsulated metal NPs: metallofullerenes and carbon-encapsulated iron carbide (FeC@C). The creation of FeC@C NPs involves heating ferrocene particles with carbon allotropes under high pressure, which is a simpler process that incurs lower production costs and yields higher output than metallofullerene synthesis. In contrast to this method, our team has proposed an innovative, cost-effective approach to producing FeC@C NPs, with a focus on their use in various photovoltaic devices.
We utilised aerosol-synthesized carbon nanotubes (CNTs), which employ ferrocene as a catalyst. As a result, the resultant CNT films invariably contain FeC@C NPs. While these are typically considered impurities by CNT researchers, and excess amounts can decrease the electrical performance of the CNTs, we've identified an opportunity to harness their potential. Rather than discarding these samples, we've found that FeC@C NPs can be selectively extracted from the CNTs. We've demonstrated a method for doing so, and have further applied them to PSCs as plasmonic light and charge transport enhancers, without inducing ion migration. The extraction process involved sonication, centrifugation, and filtration, yielding FeC@C NPs with a diameter of approximately 5–20 nm. Interestingly, these NPs exhibited a propensity for aggregation over time, a characteristic we attributed to the π–π interaction between the surrounding graphitic carbon layers. This was determined through various analyses, including microscopic techniques. By controlling the aggregation time, we were able to produce diverse plasmon modes through gap plasmon coupling between the constituent NPs. This offers the potential to manipulate the optical properties via different nano-assemblies, a step forward in our pioneering application of these materials.
Novel Fullerene Derivatives [유기합성으로 만드는 신규 풀러렌 유도체]
Pristine fullerenes, constructed solely from carbon atoms meticulously assembled in closed cages showcasing pentagonal and hexagonal configurations, have attracted tremendous attention for their potential use in various applications. However, inherent limitations prevent them from realizing their maximum potential. Prof IL Jeon has been synthesising novel fullerene derivatives, which introduce supplementary functional groups into the pristine fullerenes, offering even greater advantages to pristine fullerenes.