Tuning Dielectric Constant of P3HT by Ultrasound-Induced Aggregation

초록

Poly(3-hexylthiophene) (P3HT), a semiconducting polymer, is integral to the development oforganic electronic devices. Its optoelectronic properties are significantly influenced by the nature of itsintermolecular interactions, predominantly classified as J-type and H-type couplings. This study investigatesthe effect of sonication on the dielectric properties of P3HT, focusing on the transition from J-type (or lessprominent H-type) to H-type intermolecular interactions, accompanied by disorder-order transformation. Theresearch determined that sonication leads to a significant change in the dielectric properties of P3HT byforming distinct ordered regions interspersed within disordered or quasi-ordered areas. Specifically, there isan observable transition from J-type to H-type aggregation, which has profound effects on the material'selectronic structure and optoelectronic performance. This transition was confirmed by changes in theabsorption and photoluminescence spectra, indicating a more localized electronic character and the formationof non-emissive excitons in the case of H-aggregates. Increased dielectric constant after sonication isattributed to interface polarization, especially the Maxwell-Wagner-Sillars polarization. This effect is likelybecause new interfaces are created between the ordered regions and disordered/quasi-ordered regions withinthe P3HT material, where charges can accumulate as a result of disorder-order transformation. Our researchcontributes to the broader understanding of polymer physics and the development of organic electronic devicesby showing how the manipulation of microstructural environments can control material properties.

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