Crystalline Co-Assemblies of Functional Fullerenes in Methanol with Enhanced Charge Transport

Supramolecular arrangement of conjugated molecules has crucial influence on their material properties. For fullerenes and metallofullerenes, tight and ordered packing is beneficial for intermolecular charge transport and energy transfer, but it is tricky to achieve, especially for functionalized cages due to the often extensive solvation and steric effects of functional groups. In this study, we use an amphiphilic fullerene derivative soluble in methanol to form co-assemblies with insoluble fullerene derivatives, pristine fullerene, and metallofullerene via strong π–π interactions. These mixtures are processable in methanol and show fullerene-templated crystalline structures in spin-cast films. Devices are successfully fabricated on a field-effect transistor platform with this approach, and all co-assemblies show metallic-like conductive properties with significantly enhanced conductivity compared to the pure amphiphilic fullerene derivative.