A supramolecular polymeric heterojunction composed of an all-carbon conjugated polymer and fullerenes

Herein, we design and synthesize a novel all-carbon supramolecular polymer host (SPh) containing conjugated macrocycles interconnected by a linear poly(para-phenylene) backbone. Applying the supramolecular host and fullerene C60 as the guest, we successfully construct a supramolecular polymeric heterojunction (SPh⊃C60). This carbon structure offers a means to explore the convex–concave π–π interactions between SPh and C60. The produced SPh was characterized by gel permeation chromatography, mass spectrometry, FTIR, Raman spectroscopy, and other spectroscopies. The polymeric segment can be directly viewed using a scanning tunneling microscope. Femtosecond transient absorption and fluorescence up-conversion measurements revealed femtosecond (≪300 fs) electron transfer from photoexcited SPh to C60, followed by nanosecond charge recombination to produce the C60 triplet excited state. The potential applications of SPh⊃C60 in electron- and hole-transport devices were also investigated, revealing that C60 incorporation enhances the charge transport properties of SPh. These results expand the scope of the synthesis and application of supramolecular polymeric heterojunctions.