Polymorphism in the self-assembled nanostructures of a tris(phthalocyaninato) europium derivative: Phase-dependent semiconducting and NO2 sensing behaviour

Three different phases (χ-, β-, and α-form) triggered by different solvent systems are observed for Eu2[Pc(OCH2CF3)4]3 nanostructures for the first time, which in turn exhibit phase-dependent semiconducting and NO2 gas sensing performance with the χ phase nanostructure showing the thus far best room temperature-operated sensing property with ultrahigh sensitivity, low detection limit, and good reversibility and selectivity.126