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Efficient exciton dissociation at low energy offsets is key to overcoming voltage losses in organic solar cells. In this work, we developed two dimeric acceptors, i-YT and o-YT, by precisely controlling the position of an asymmetric electron-donating linker. It induced the foldamer conformation of i-YT with a para linkage (relative to the dicyano groups), while retaining the unfold conformation for o-YT. This subtle structural modification influenced the molecular assembly properties, enabled near-zero energy offset exciton dissociation and power conversion efficiencies exceeding 18 % for i-YT based organic solar cells. Detailed excitonic dynamics further revealed that the linker position critically influences three processes: the formation of delocalized singlet excited states, ultrafast charge transfer (~5 ps) in solid blends, and the suppression of exciton recombination. Additionally, devices based on i-YT demonstrated outstanding long-term stability, retaining 85 % of their initial efficiency after 1,400 hours of continuous illumination. These findings introduce a new class of dimeric acceptors that combine high efficiency with exceptional stability, offering a promising pathway toward low-energy-loss organic photovoltaics., (© 2024 Wiley-VCH GmbH.)

Hybrid rod-rod diblock copolymers, poly(γ-benzyl L-glutamate)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PBLG-PPI), with determined chirality are facilely synthesized through sequential copolymerization of γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and phenyl isocyanide monomers bearing chiral menthyl pendants using a Ni(cod)(bpy) complex as the catalyst in one-pot. Circular dichroism and absorption spectra reveal that each block of the block copolymers possesses a stable helical conformation with controlled helicity in solution due to the induction of chiral pendants. The two diastereomeric polymers self-assemble into helical nanofibrils with opposite handedness due to the different chiral induction of the L- and D-menthyl pendants, confirmed by transmission electron microscopy (TEM). Deprotection of the benzyl groups of the PBLG segment affords biocompatible amphiphilic diblock copolymers, poly(L-glutamic acid)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PLGA-PPI), that can self-assemble into well-defined micelles by cosolvent induced aggregation. Very interestingly, a chiral rhodamine chromophores RhB(D) can be selectively encapsulated into the chiral polymeric micelles, which is efficiently internalized into living cells when directly monitored with a confocal microscope. This contribution will be useful for developing novel rod-rod biocompatible hybrid block copolymers with a controlled helicity, and may also provide unique chiral materials for potential bio-medical applications., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)