Synthesis of Novel Hyperbranched Polybenzo-Bisthiazole Amide with Donor–Acceptor (D-A) Architecture, High Fluorescent Quantum Yield and Large Stokes Shift

Abstract

Two novel highly fluorescent hyperbranched polybenzobisthiazole amides with a donor-acceptor architecture and large Stokes shift were rationally designed and synthesized. The chemical structures of the prepared hyperbranched polymers were characterized using Fourier Transform Infrared Spectroscopy (FTIR) analysis, Hydrogen Nuclear Magnetic Resonance ( 1 H-NMR) analysis, and Gel Permeation Chromatography (GPC) analysis. These two polymers were soluble in dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), and their DMSO and DMF solutions emitted strong green light (517-537 nm) with high quantum yields (QYs) and large Stokes shifts. Their relative fluorescence QYs in the DMSO solution were calculated as 77.75% and 81.14% with the Stokes shifts of 137 nm (0.86 eV) and 149 nm (0.92 eV) for HP-COOH and HP-NH 2 , respectively, using quinine sulfate as the standard. In the DMF solution, the QYs of HP-COOH and HP-NH 2 were calculated as 104.65% and 118.72%, with the Stokes shifts of 128 nm (0.79 eV) and 147 nm (0.87 eV), respectively. Their films mainly emitted strong blue light with the maximum emission wavelengths of 436 nm and 480 nm for HP-COOH and HP-NH 2 , respectively. The Stokes shifts for HP-COOH and HP-NH 2 films were 131 nm (0.42 eV) and 179 nm (0.86 eV), respectively. They are promising candidates for luminescent solar concentrators and blue light emitting materials.

Synthesis and Characterization of White-Light Luminescent End-Capped Polyimides Based on FRET and Excited State Intramolecular Proton Transfer

“…To overcome this problem, the uses of excited-state intramolecular proton transfer (ESIPT) and intersystem crossing (ISC) followed by phosphorescence emission are advantageous [21,28,33]. In addition, molecules having a donor-acceptor structure exhibit large Stokes-shifted fluorescence owing to the effective spatial separation of HOMO and LUMO [34]. The Förster resonance energy transfer (FRET) is a well-known energy transfer phenomenon [35], in which the excitation energy between two chromophores in close distance is directly transferred through non-radiative dipole-dipole coupling, and has been applied to white light-emitting materials [36].…”

Single-Component Polycondensation of Bis(alkoxycarbonyldiazomethyl)aromatic Compounds To Afford Poly(arylene vinylene)s with an Alkoxycarbonyl Group on Each Vinylene Carbon Atom

“…This larger Stokes shift of poly6′ could be ascribed to the significant conformational change in an excited state in the solution, resulting in variations in the twist angle between neighboring fluorene rings. 22 As for the UV−vis absorption spectrum in the film state (Figure 4b), no bathochromic shift was observed (λ max = 345 nm) in comparison with the solution state, suggesting that polymer-chain aggregation was restricted in the solution owing to the long alkyl chains both in fluorenylene and ester moieties.…”

“…In addition, a significantly red-shifted emission (540 nm of emission maximum) was observed in the poly6′ solution compared with that in the PFV solution (450 nm of emission maximum), resulting in a much larger Stokes shift of poly6′ [195 nm ( poly6′ ) vs 60 nm (PFV)]. This larger Stokes shift of poly6′ could be ascribed to the significant conformational change in an excited state in the solution, resulting in variations in the twist angle between neighboring fluorene rings …”

AIENP‐Reinforced DISCO Method for Whole‐Tissue 3D Reconstruction of Pulmonary Capillaries

“…The PL spectra suggested that AIENPs showed near‐infrared emission maxima (≈620 nm) and a large Stokes shift (240 nm) (Figure 2D) that is attributed to the donor‐acceptor (D‐A) architecture which imparts intramolecular charge transfer character. [ 12 ] The AIENPs also showed good photostability (Figure 2E). Additionally, we conducted the in vitro cytotoxicity assessment using the CCK‐8 assay.…”