Fullerene is a new class of nanomaterial, which was firstly discovered and reported by Kroto, Smalley and Curl in 1984. Fullerenes are hollow cage-like structures composed of twelve pentagonal rings and several hexagonal rings. Since the pentagonal ring is a tension ring and the hexagonal ring is a non-tension ring, the structure and stability of fullerenes are controlled by the isolated-pentagon rule. If there are two or more pentagonal ring distributed adjacent to each other on the sphere of fullerenes, the system will be unstable due to large tension and thus exhibit more active chemical properties. Therefore, for fullerenes, the most stable geometry should contain the fewest number of adjacent pentagonal ring. The size of the fullerenes is in the nanometer level, and they have the quantum size effect, small size effect, surface effect and macroscopic quantum tunneling effect. Therefore, fullerenes exhibit many unique properties and have broad application prospect in the organic chemistry, inorganic chemistry, life science, material science, polymer science, catalytic chemistry, electrochemistry, superconductor and the others.
- Catalytic reaction field: Fullerenes can catalyze a variety of chemical reactions, including organic reactions, reactions producing singlet oxygen, reactions of graphite synthesis of diamond, and combustion processes of high-energy fuels. They can improve many traditional synthetic reactions, and increase the reaction rate. For example, fullerenes have a strong ability to open strong bonds and participate in hydrogen transfer reactions, which has greatly facilitated the conversion of methane into high-carbon hydrocarbons.
Figure 1. An example of fullerene used in catalytic reaction field.
- Solar cell field: Among the renewable energy sources such as solar energy, wind energy, hydrogen energy and coal vaporization, photovoltaic energy that converts solar energy into electricity is one of the most promising energy sources in the future. Solar cells can efficiently convert light energy into electricity, thus realizing the application of sunlight. Fullerenes and their derivatives are used as electron acceptor materials in the design of solar cells. For example, fullerenes are excellent electron acceptor materials for polymer solar cells due to their unique three-dimensional conjugated structure.
Figure 2. An example of fullerene used in solar cell.
- The others: Fullerenes can also be used in a number of fields, including drug delivery, cancer treatment, antimicrobial agents and the others. For example, fullerenes exhibit antimicrobial activity, which can be attributed to different interactions between fullerenes and biomolecules. Fullerenes can be inserted into the biofilm and damage the structure of the biofilm, which can inhibit candida albicans, bacillus subtilis, enterococcus and mycobacterium avium.
According to the number of carbon atoms, fullerenes can be divided into C60 and C70, large carbon fullerenes and small carbon fullerenes
- C60 and C70: C60 and C70 are the two most common fullerenes. In addition, C60 is the smallest fullerenes that meet isolated-pentagon rule .
- Large carbon fullerenes: Large carbon fullerenes contain more than 70 carbon atoms, mainly including C76, C80, C84, C90, C94, C120, C180, C540 and the others.
- Small carbon fullerenes: There is a large tension in the structure of small carbon fullerenes. Therefore, small carbon fullerenes have high chemical activity and is difficult to be synthesized and separated. The researches on small carbon fullerenes mainly focuses on C20, C24, C28, C32, C36, C40, C44, C50 and C2n (n =26-29) and their derivatives.
- Girón, Rosa M, Marco-Martínez, Juan, Bellani S, et al. Synthesis of modified fullerenes for oxygen reduction reactions[J]. Journal of Materials Chemistry A, 2016.
- Sugawara K, Nakamura N, Yamane Y, et al. Influence of chirality on the cyclohexene-fused C60 fullerene derivatives as an accepter partner in a photovoltaic cell[J]. Green Energy and Environment, 2016.