Metal-dependent Excited-State Dynamics and Charge Transport in Copper and Silver Corrole-Fullerene Dyads

Abstract

We report a class of covalently linked metallocorrole-fullerene dyads that integrate molecular-level design with device-relevant charge transport. Copper- and silver-corrole units are fused to C60 via a pyrrolidine linker. SC-XRD of the silver dyad reveals unusually short C60···Ag(III) contacts (2.96 Å), evidencing strong donor–acceptor coupling. Steady-state spectra show fulleropyrrolidine absorptions and subtle Soret/Q-band shifts upon conjugation. DFT reveals a HOMO delocalized over the corrole-phenylene framework and distinct LUMO distributions, with spin-dependent localization in the copper dyad and fullerene localization in the silver dyad. Electrochemistry resolves metallocorrole oxidations and fullerene reductions, while Rehm–Weller analysis indicates feasible photoinduced charge separation. Ultrafast transient absorption uncovers a heavy-atom-assisted route: rapid singlet–singlet energy transfers to the fulleropyrrolidine followed by accelerated intersystem crossing, with no spectroscopic signature of a charge-separated state on the fs-ns window. Indication of charge separation is instead found in the ns-μs time window for the copper dyad. Solid-state space-charge-limited current measurements reveal complementary transport behavior: the silver dyad functions as a high-mobility p-type material, whereas the copper dyad exhibits reasonable electron and hole mobility, which can be correlated to the energetic landscape of these molecules. Together, these results establish metallocorrole-fullerene dyads as tunable platforms that bridge excited-state dynamics with long-range charge transport for organic optoelectronic applications.