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Core Halogenation as a Construction Principle in Tuning the Material Properties of Tetraazaperopyrenes
Author(s) -
Hahn Lena,
Maaß Friedrich,
Bleith Tim,
Zschieschang Ute,
Wadepohl Hubert,
Klauk Hagen,
Tegeder Petra,
Gade Lutz H.
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503484
Subject(s) - halogenation , homo/lumo , cyclic voltammetry , halide , substrate (aquarium) , chemistry , band gap , spectroscopy , materials science , photochemistry , computational chemistry , molecule , electrochemistry , organic chemistry , electrode , optoelectronics , physics , oceanography , quantum mechanics , geology
A detailed study on the effects of core halogenation of tetraazaperopyrene (TAPP) derivatives is presented. Its impact on the solid structure, as well as the photophysical and electrochemical properties, has been probed by the means of X‐ray crystallography, UV/Vis and fluorescence spectroscopy, high‐resolution electron energy loss spectroscopy (HREELS), cyclic voltammetry (CV), and DFT modeling. The aim was to assess the potential of this approach as a construction principle for organic electron‐conducting materials of the type studied in this work. Although halogenation leads to a stabilization of the LUMOs compared to the unsubstituted parent compound, the nature of the halide barely affects the LUMO energy while strongly influencing the HOMO energies. In terms of band‐gap engineering, it was demonstrated that the HOMO–LUMO gap is decreased by substitution of the TAPP core with halides, the effect being found to be most pronounced for the iodinated derivative. The performance of the recently reported core‐fluorinated and core‐iodinated TAPP derivatives in organic thin‐film transistors (TFTs) was investigated on both a glass substrate, as well as on a flexible plastic substrate (PEN). Field‐effect mobilities of up to 0.17 cm 2 Vs −1 and on/off current ratio of >10 6 were established.