Curved Nanocarbon Hosts for Fullerenes: Design, Assembly, and Functionalities

ConspectusCurved nanocarbon molecules, characterized by their nanoscale dimensions and nonplanar π-surfaces, have attracted considerable research interest owing to their distinct physicochemical properties dictated by molecular topology. The introduction of curvature─manifested as hoops, bowls, tweezers, cages─fundamentally modifies electronic structures relative to their planar analogues: it weakens π-bonds, induces asymmetric electron density distribution across concave and convex surfaces, and lowers the energy of the lowest unoccupied molecular orbitals (LUMOs). These electronic perturbations lead to unique optical behavior, polarity, charge transport characteristics and self-assembly propensity. Fullerenes, with their curved, electron-deficient spherical π-surfaces, have emerged as ideal guests in supramolecular chemistry. Their complexation with complementary curved nanocarbon hosts enables the construction of sophisticated assemblies with advanced functionalities, such as high-performance charge transport layers in organic field-effect transistors (OFETs), selective purification of fullerenes via kinetic differentiation (e.g., C60 vs C70), and ultrafast photoinduced charge separation in heterojunctions.A central challenge, however, lies in the design and precise construction of curved nanocarbon molecules, which is hampered by the high intramolecular strain inherent to curved π-frameworks. To address this, our group has developed and applied a suite of synthetic strategies─including flash vacuum pyrolysis (FVP), gold-mediated dimerization, incorporation of pentagon defects, meticulous design of active ring-closing motifs, and dynamic coordination-driven assembly─to successfully construct four principal types of curved nanocarbon hosts.Key advances covered in this Account include the following: (i) Synthesis and Assembly of Tailored Nanocarbon Hosts. We have developed hoop-shaped nanographenes that exploit radial π-conjugation to form the first ternary CPP-based co-crystals; cage-like nanographenes capable of encapsulating C60 dimers with a record 104-fold photoluminescence enhancement; tweezer-like hosts that combine π–π and n−π interactions for high selectivity; and bowl-shaped buckybowls, notably the flexible, electron-rich decapyrrylcorannulene (DPC), whose molecular conformations and electronic properties dictate specific binding behaviors toward a wide range of fullerenes. (ii) Functional Applications of Host–Fullerene Complexes. These supramolecular systems exhibit enhanced photoconductivity, enable high-efficiency solar cells, and facilitate versatile fullerene recognition and structural analysis. Representative examples include sulfur-doped buckybowl–fullerene stacks that show a 400% increase in electrical conductivity; corannulene–C60 assemblies that serve as solution-processable electron transport layers (ETLs) in inverted perovskite solar cells (PSCs), achieving a record power conversion efficiency (PCE) of 21.69%; and the universal host DPC, which allows structural elucidation of 15 different fullerenes, including endohedral metallofullerenes (EMFs) and heterofullerenes.Collectively, our work establishes curved nanocarbon hosts as transformative building blocks that bridge synthetic innovation and functional excellence. In this Account, we highlight the potential of these supramolecular systems in emerging applications such as photoconductivity, solar energy conversion, and precise molecular analysis. We also outline future directions, with an emphasis on stereoselective recognition and optical resolution of chiral fullerenes using tailored chiral curved nanocarbon hosts. Realizing such enantioselective platforms could unlock the potential of chiral fullerene-based materials and open a new chapter in fullerene supramolecular chemistry.