Supramolecular Engineering of Crystalline Fullerene Micro-/Nano-Architectures

Fullerenes are a molecular form of carbon allotrope and bear certain solubility, which allow the supramolecular assembly of fullerene molecules-also together with other complementary compound classes-via solution-based wet processes. By well-programmed organizing these building blocks and precisely modulating over the assembly process, supramolecularly assembled fullerene micro-/nano-architectures (FMNAs) are obtained. These FMNAs exhibit remarkably enhanced functions as well as tunable morphologies and dimensions at different size scales, leading to their applications in diverse fields. In this review, both traditional and newly developed assembly strategies are reviewed, with an emphasis on the morphological evolution mechanism of FMNAs. The discussion is then focused on how to precisely regulate the dimensions and morphologies to generate functional FMNAs through solvent engineering, co-crystallization, surfactant incorporation, or post-fabrication treatment. In addition to C₆₀ -based FMNAs, this review particularly focuses on recently fabricated FMNAs comprising higher fullerenes (e.g., C₇₀ ) and metallofullerenes. Meanwhile, an overview of the property modulation is presented and multidisciplinary applications of FMNAs in various fields are summarized, including sensors, optoelectronics, biomedicines, and energy. At the end, the prospects for future research, application opportunities, and challenges associated with FMNAs are proposed.

Interfacial Reaction of Fulleropyrrolidines Affecting Organic Photovoltaic Performance

Fulleropyrrolidine derivatives are intrinsically basic owing to the amino group within the pyrrolidine structure. It can be predicted that the basicity of fulleropyrrolidine may affect the photovoltaic devices containing an acidic layer (e.g.

, PEDOT

PSS). To clarify the effect of basic fulleropyrrolidine derivatives, we synthesized compounds with an N-benzyl substituent group and fabricated organic photovoltaic (OPV) cells using this N-benzyl fulleropyrrolidine. A device structure with the ITO/PEDOT:PSS/organic layer (PTB7:fulleropyrrolidine)/Ca/Al showed high series resistance, short-circuit current density (J_sc), and low fill factor (FF) values. However, OPV cells having an inverted structure, without the PEDOT:PSS layer, contributed good device performance. We were able to reproduce the high series resistance in a model experiment using aqueous ammonia vapor to treat the PEDOT:PSS layer. Our results indicated that the activity of the PEDOT:PSS layer was affected by the basicity of the fulleropyrrolidines. These results also explain why this phenomenon does not occur at the interface of OPV devices when conventional [6,6]-phenyl C₆₁ butyric acid methyl ester is used as an acceptor material. This finding would contribute to enhancing the OPV device performances from a chemical view point of designing a new compound.

Synthesis and study of hybrid hydrogen-bonded bent-core liquid crystal complexes containing C60- and Si-based proton donors

Mesophasic and electro-optical properties can be manipulated via the ratio of Si- and C₆₀-based moieties in H-bonded bent-core LC complexes.