Judging Panel

  • Prof. Catherine MICHAUX (UNamur), Chair
  • Prof. Yoann OLIVIER (UNamur), Secretary
  • Prof. Riccardo ALESSANDRI (Katholieke Universiteit Leuven)
  • Prof. Sylvain GABRIELE (University of Mons)
  • Prof. Olivier DEPARIS (UNamur)
  • Prof. Vincent LIEGEOIS (UNamur)

Abstract

This thesis presents a multiscale investigation of the nanomechanical properties and deformation mechanisms of organic semiconductors, which are best known for their optoelectronic properties. It examines their mechanical behavior in the context of increasing structural complexity, from individual molecular interactions to crystalline and polymeric materials. Computational results are systematically compared with available experimental measurements. The molecular dynamics methods used throughout this work are introduced and applied to various topics of current interest in the field.

 In this thesis, the following topics were investigated: (i) the force-induced dissociation and conformational unfolding pathways of individual π–π interactions in perylene derivative dimers, (ii) the anisotropic elastic properties of high-mobility DNTT molecular crystals and the influence of alkyl-chain functionalization on their mechanical rigidity, and (iii) the impact of microstructure—ranging from crystalline to amorphous phases—as well as F4TCNQ doping on the nanomechanical properties of PBTTT. In all of the applications described above, the computational results are compared with experimental data across these different structural scales to assess the predictive capabilities of the modeling approaches and identify the molecular and structural factors that govern the mechanical response of organic semiconductors. Finally, the conclusions are presented alongside future directions aimed at achieving a better understanding of—and ultimately the rational design of—mechanically tunable organic semiconductors for use in flexible electronics.