Аннотация:A series of novel highly soluble double-caged [60]fullerene derivatives were prepared by means of lithium salt-assisted [2+3]-cycloaddition. The bispheric molecules feature rigid linking of the fullerene spheres via a four-membered cycle and a pyrrolizidine bridge with an ester function CO2R (R=n-decyl, n-octadecyl, benzyl, and n-butyl: compounds 1a-d, respectively), as demonstrated by NMR spectroscopy and X-ray diffraction. Cyclic voltammetry studies revealed three closely overlapping pairs of reversible peaks due to consecutive one-electron reductions of fullerene cages, as well as an irreversible oxidation peak attributed to abstraction of an electron from the nitrogen lone electron pair. Due to charge delocalization over both carbon cages, compounds 1a-d are characterized by upshifted energies of frontier molecular orbitals, narrowed band gap, and reduced electron transfer reorganization energy compared to pristine C60. Neat thin films of the n-decyl compound 1a demonstrated the electron mobility (1.3 ± 0.4)×10-3 cm2V-1s-1, comparable to PCBM and thus potentially advantageous for organic solar cells (OSC). An application of compounds 1 in OSC allowed a two-fold increase in power conversion efficiencies of as-cast P3HT/1 devices compared to the P3HT/PCBM ones. This is attributed to good solubility of 1 and their enhanced charge transport properties, both intramolecular, due to tightly linked fullerene cages, and intermolecular, due to large number of close contacts between the neighboring double-caged molecules. Test P3HT/1 OSCs demonstrated power conversion efficiencies up to 2.6% (1a). Surprisingly low optimal content of double-caged fullerene acceptor 1 in the photoactive layer (ca 30 wt%) favored better light harvesting and carrier transport due to larger content of P3HT and its higher degree of crystallinity.