Molecular ordering of A(D–A′–D)2-based organic semiconductors through hydrogen bonding after simple cleavage of tert-butyloxycarbonyl protecting groups

Abstract

We have successfully achieved the molecular ordering of semiconducting small molecules comprising a newly designed A(D–A′–D)₂ system. The A(D–A′–D)₂ small molecules have two different acceptors based on isoindigo and diketopyrrolopyrrole along with tert-butoxycarbonyl (t-Boc) groups and hexyl chains, which improve the solubility of the materials. After simple thermal annealing, the t-Boc groups were removed to allow strong hydrogen bonds between N–H⋯CO to form, and this resulted in improved molecular ordering of the organic semiconductors. The crystalline morphology was confirmed by X-ray diffraction coupled with high-voltage electron microscopy, and the resulting materials showed improved hole mobilities. In this work, the effect of the incorporation of t-Boc groups onto A(D–A′–D)₂-based organic semiconductors on their morphological and electrical properties was evaluated.