Nanoscale Columnar Bundles Based on Multistranded Core–Shell Liquid Crystals of Perylene Bisimide J-Aggregate Donor–Acceptor Dyads for Photoconductivity Devices with Enhanced Performance Through Macroscopic Alignment

Donor–acceptor dyads consisting of perylene bisimide (PBI) and trialkoxyphenyl–oligothiophene (TAPOT) units are reported that self-assemble into helical four-, six-, and seven-stranded hydrogen-bonded supramolecular polymers in solution and the columnar liquid-crystalline state. It is shown that the number of closely stacked and J-coupled PBI strands can be controlled by the incremental extension of the TAPOT wedge units in the bay position and the thereby tailored steric demand. Narcissistic self-sorting of TAPOT donor and PBI acceptor subunits facilitates the formation of core–shell structures creating individual percolation pathways for one-dimensional (1D) transport of photogenerated charge carriers. Macroscopic alignment of the nanoscale columnar structures by solution shearing enables anisotropic photoconductivity. Thus, selective orientation of the 1D charge-transporting domains parallel and perpendicular to the electrodes gives rise to an up to 90-fold increased photoresponse depending on the alignment quality. The intrinsic charge-separation and -transport properties were investigated by femtosecond transient absorption spectroscopy and flash-photolysis time-resolved microwave conductivity. These studies reveal a rising propensity for charge separation and transport upon increasing the conjugation length of the TAPOT donor and thereby increasing the size of the individual percolation pathways. Contrasting observations for intrinsic and macroscopic photoconductivities demonstrate the importance of processability in device performance.