Optical Tuning of the Fluorescence Spectrum of a π-Conjugated Polymer through Excitation Power

Abstract

The photophysical properties of a π-conjugated polymer containing 2,2'-bipyridyl alternated with 2,5-dihexyloxyphenylene units (PBPyDHP) are investigated experimentally in terms of the conditions used (solvent, concentration, presence or absence of molecular oxygen, and optical excitation power). The experimental results have suggested that the fluorescence from PBPyDHP can be tuned by proper selection of the experimental conditions showing only one or two emission peaks: 445 nm (blue) and 555 nm (green). The observed effects were interpreted in terms of the twisted intramolecular charge transfer (TICT) theory. This is the first experimental report showing the interconversion of an usual fluorescence, called locally emission state (LE), to a TICT state in second scale time by varying the excitation power; that is, even though the torsion of only one fluorophore occurs in a nano or picosecond scale, the global change (the interconversion for all fluorophores) has occurred in the second time scale.

Polymer Nanofibers with Outstanding Thermal Conductivity and Thermal Stability: Fundamental Linkage between Molecular Characteristics and Macroscopic Thermal Properties

“…Due to the outstanding electronic–photonic properties and thermochemical stability, π-conjugated materials are applied in many areas, including chemical sensors, light-emitting diodes, photovoltaics, and cancer treatment. − In π-conjugated molecules, the overlap of the p-orbitals also imposes strong constraints that suppress bond rotation and thus lead to rigid backbones. − Polyacetylene (PA) is the simplest π-conjugated polymer (structure shown in Figure ). In the COMPASS potentials, the dihedral potential is presented by a sum of three cosine functions (eq ).…”

Humidity-Controlled Tunable Emission in a Dye-Incorporated Metal–Hydrogel–Metal Cavity

“…Several ways exist to actively tune the emission properties. These include the application of magnetic, , electric, and optical , fields. Furthermore, a diverse range of tunable metasurfaces based on mechanical actuation, − phase-change materials, − and liquid crystals − exist, offering dynamic tuning of optical properties.…”