Mechano-Optoelectronic and Micro-Mechanical Properties of Conjugated Polymeric Thin Films with Nano-Structured Lamellae

In this study, we aim to deepen understanding about the process-structure-property (PSP) relationship of the mechano-optoelectronic thin films where the conjugated poly(3-hexylthiophene) (P3HT) polymers form nano-structured lamellae. The MO thin films are known for the multifunctional capability of the radiant-electrical energy conversion and the direct current (DC)-based strain sensing capability. In the MO thin films, the p-type semiconducting P3HTs form crystalline domains along with n-type semiconducting fullerene derivatives to form p-n bulk heterojunction (BHJ), where holes and electrons are dissociated to generate DC upon the photonic energy introduction at the p-n junctions (i.e., the radiant-electrical energy conversion). In addition, it was shown that the optoelectronic property of the P3HT-based thin film was affected by the amount of the mechanical strain by which the thin film was stretched (i.e., MO property). The MO property has been hypothesized to be attributed to the varying nano-structures of P3HTs resulting from the macro-scale mechanical strain applied onto the P3HT-based thin films. As it is known that the nano-structures of P3HTs are greatly influenced by the manufacturing processes, we plan to study how the P3HTs’ nano-structures are affected by the spin-coating and the air-brushing processes to understand the PSP relationship of the P3HT-based MO thin films.