Design, Synthesis, and Property Tuning of Spin-Coated Chiral Polymer Films for Advanced Photonic Applications

Chiral photonics research is increasingly centered on developing thin films that manipulate optical properties through enantioselective methods, offering promising applications in optical signal processing, sensing, and molecular spintronics. These thin films provide unique opportunities for controlling linear and nonlinear optical behavior, making them ideal candidates for advanced photonic devices and coatings. In this study, we focus on the development of thin spin-coated chiral polymer films, synthesized through the copolymerization of chiral fluorene monomers with thiophene comonomers via the Suzuki polycondensation method. By modulating the conjugation units within the monomer, we precisely control the chiroptical properties of the thin films, enabling their use in various photonic applications. We employ several strategies to enhance the optical activity of these films, including the incorporation of supramolecular softeners (PEM-OH) and plasmonic doping during the film deposition process. These approaches facilitate spatiotemporal control over the chiroptical properties via in situ photopolymerization, demonstrating significant enhancements in the optical performance of the thin films. Furthermore, we achieve substantial improvements in magneto-optic (MO) properties in these thin films, with a high Verdet constant, surpassing the performance of existing MO materials. The spin-coated chiral polymer films demonstrate great potential for applications such as optical isolation, weak magnetic field mapping, and advanced coating technologies for metamaterial design. The ability to manipulate the electric and magnetic dipole coupling in these thin films opens new possibilities for controlling MO effects across a wide range of wavelengths, positioning these materials at the forefront of chiral photonics and optoelectronics