Mechano-Optoelectronic Conjugated Polymeric Thin Films with Nano-Structured Lamellae for Self-Sensing of Mechanical Strain*

Mechano-optoelectronic (MO) thin films generate electrical energy in direct current (DC) using an external light source. The generated DC was shown to vary with the mechanical strain that the MO thin films are subjected to. The unique strain-sensitive DC generation characteristic of the MO thin films permitted to devise a self-powered strain sensor for self-sensing mechanical strains. The MO thin films were fabricated by depositing p-n semiconducting polymer solution on a flexible substrate using a spin-coating technique. The p-type conjugated poly(3-hexylthiophene) (P3HT) was known to play a pivotal role in the strain-sensitive DC generation due to varying nano-structures of P3HT in the MO thin films subjected to mechanical deformation. 

In this study, we aim to understand how the MO properties of the thin films are affected by the nano-structures of the P3HT through empirical and simulation studies. The MO thin films will be fabricated using P3HTs with different regioregularities on a flexible substrate using a spin-coating technique. The fabricated MO thin films will be tested to measure DC output with mechanical strains applied onto the thin films. Also, using small angle X-ray scattering (SAXS), the nano-structures of the conjugated polymers will be characterized at different strain levels. The SAXS data will be used for modeling the conjugated polymers with different nano-structures using the molecular dynamics (MD) code to help understand how the nano-structures are related to the MO properties.