Charge Transport in Thin‐Film Transistors Based on Liquid‐Crystalline Phthalocyanines

We investigate a series of liquid‐crystalline phthalocyanines (metal‐free and Cu, Zn, Ni, Co complexes) and their electronic performance as active layers in organic thin‐film transistors (OTFTs). Raman spectroscopy reveals metal‐dependent distortions of the phthalocyanine macrocycles, reflected in systematic shifts of the C−N−C and M−N vibrational modes. When integrated into OTFTs, all compounds exhibited markedly enhanced current response under ultrahigh vacuum compared to an N ₂ ‐ atmosphere, demonstrating that intrinsic charge transport is suppressed by atmospheric species. Temperature‐dependent measurements (in the 100–300 K range) revealed that the threshold‐voltage shifts in the devices were driven by deep interface and bulk traps, while all devices displayed thermally activated mobility with low activation energies (≈14–20 meV). These results highlight how mesomorphic order, metal coordination, and environmental conditions collectively govern charge transport in liquid‐crystalline phthalocyanines, offering design guidelines for their use as self‐assembled semiconducting materials in organic electronics. Our results therefore represent a systematic characterization of liquid‐crystalline phthalocyanine‐based OTFTs, revealing low trap‐barrier energies and efficient charge‐hopping pathways present in these materials.