Rubbing induced reversible fluorescence switching in thiophene-based organic semiconductor films by mechanical amorphisation

Here, we applied rubbing on thiophene-basedorganic 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 films produces an opposite effect with respect to rubbing, inducing film crystallization. Notably, thermal crystallisation starts at a low temperature but generates the polymorph stable at a 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.

Automated summary

Rubbing was used on thiophene-based organic semiconductor thin films to induce reversible mechanical amorphisation, which is associated with fluorescence switching regulated by the film's polymorphic nature. Thermal annealing of the films produced an opposite effect, inducing film crystallization starting at a low temperature and generating a stable polymorph at high temperatures in the bulk. The mechanism of mechanical transformation was explained considering the material's mechanical properties and demonstrated through X-ray diffraction, atomic force microscopy, and photoluminescence at confocal microscopy.