Here, we applied rubbing on thiophene derivate organic semiconductor thin films to induce a reversible mechanical amorphisation. Amorphisation is associated with fluorescence switching, which is regulated by the polymorphic nature of the film. Thermal annealing of rubbed film produces an opposite effect with respect to rubbing, inducing the film crystallization. Notably, thermal crystallisation starts at low temperature but generates the polymorph stable at high temperature in the bulk. The mechanism of mechanical transformation is explained considering the mechanical properties of the material and demonstrated through combined X-ray diffraction, Atomic force microscopy and photoluminescence at confocal microscopy.
Royal Society of Chemistry
1 Jan 2021
Journal of Materials Chemistry C