Photoinduced Intramolecular Charge Separation at the Repetition Units of Light-Emitting Alternating Copolymers

Abstract

Light‐emitting nitrogen‐containing poly‐ (phenylene vinylene) PPV‐related copolymers are synthesized by the well‐known Wittig‐Horner reaction. The alternating copolymers have hole‐transporting moieties such as triphenylamine (TPA) and conjugated aromatic units such as 1,4‐phenylene, 1,4‐ or 1,5‐naphthylene and 9,10‐anthrylene. The dipole moments within the repetition units of the copolymers in the excited state are estimated by measuring the solvent effect on absorption and fluorescence emission spectra, indicating that charge separation is present. The dipole moment values are in agreement with the electron affinities of acceptors, i. e. aromatic units. The evidence can help to elucidate the photophysical behavior, particularly the fluorescence quantum efficiencies.

Amorphous molecular material containing bisthiophenyl-benzothiadiazole and triphenylamine with bipolar and low-bandgap characteristics for solar cells

“…The intramoleuclar charge-transfer state could contribute to the reduction of the bandgap. In addition, as we proposed previously, a stable charge-transfer state may effectively prevent the electron backdonation after the charge separation from the donor to the acceptor molecules, such as C 60 derivatives [23,24].…”

Photophysics and Applications in Plastic Solar Cells of Conjugated Polymer/Fullerene Composites

“…Intramolecular charge transfer (ICT) from the triphenylamine moiety to the anthracene unit can occur in TPA-PAV. 7 Upon excitation at longer wavelength such as 430 nm, the fluorescence emission of TPA-PAV is mainly from its ICT states. Figure 2 shows the fluorescence spectra of TPA-PAV quenched by C 60 .…”

Solid-Phase Synthesis of Unsymmetrical trans-Stilbenes

“…Stilbene derivatives have been widely investigated as short subunits of poly( p -phenylenevinylene), which was the first light-emitting polymer to be discovered, to gain an understanding of the emission mechanism and the relationship between the substitution on the conjugated skeleton and the emitted light . Moreover, stilbene and aminostilbene derivatives exhibit blue photoluminescence and hole transport properties. Stilbene dendrimers have recently attracted considerable attention as efficient luminescent materials …”