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Strong Enhancement of π‐Electron Donor/Acceptor Ability by Complementary DD/AA Hydrogen Bonding
Author(s) -
Liu ChengHao,
Niazi Muhammad Rizwan,
Perepichka Dmitrii F.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201910288
Subject(s) - stacking , supramolecular chemistry , acceptor , ambipolar diffusion , molecule , electron acceptor , carbazole , chemistry , hydrogen bond , photochemistry , chemical physics , crystallography , materials science , electron , crystal structure , physics , organic chemistry , quantum mechanics , condensed matter physics
π‐Conjugated organic materials possess a wide range of tunable optoelectronic properties which are dictated by their molecular structure and supramolecular arrangement. While many efforts have been put into tuning the molecular structure to achieve the desired properties, rational supramolecular control remains a challenge. Here, we report a novel series of supramolecular materials formed by the co‐assembly of weak π‐electron donor (indolo[ 2,3‐a ]carbazole) and acceptor (aromatic o ‐quinones) molecules via complementary hydrogen bonding. The resulting polarization creates a drastic perturbation of the molecular energy levels, causing strong charge transfer in the weak donor–acceptor pairs. This leads to a significant lowering (up to 1.5 eV) of the band gaps, intense absorption in the near‐IR region, very short π‐stacking distances (≥3.15 Å), and strong ESR signals in the co‐crystals. By varying the strength of the acceptor, the characteristics of the complexes can be tuned between intrinsic, gate‐, or light‐induced semiconductivity with a p ‐type or ambipolar transport mechanism.