Khaled Hriz

New anthracene-based soluble polymers: optical and charge carrier transport properties

A series of anthracene-based polymers (P1–3) have been synthesized via the Wittig polycondensation. These organic materials were soluble in common organic solvents and show good film-forming abilities. Their macromolecular structures were characterized by NMR, FT-IR spectroscopies and steric exclusion chromatography, their thermal behaviors were analyzed by differential scanning calorimetry and their HOMO-LUMO energy levels were estimated by cyclic voltammetry. The optical properties of these π-conjugated systems were investigated by UV-visible absorption and photoluminescence spectroscopies. The effect of the spacer-group structure on the photo-physical behavior, π-π stacking ability and charge carrier transport properties of the polymer has been studied.

New Blue-Photoluminescent Semi-Conducting Polymer Derived from Fluorinated Bisphenol A

A new confined p-phenylenevinylene (PPV)-type polymer (BPAF-PPV ) has been synthesized using Wittig condensation. The chemical structure of the polymer was well defined by 1H-NMR, 13C-NMR, and FT-IR spectroscopic analysis. BPAF-PPV contains oligomeric PPV units separated by hexafluoroisopropylidene groups in the main chain; it is fully soluble in common organic solvents and has a number-average molecular weight of 4570 g mol-1. Differential scanning calorimetry indicates that BPAF-PPV is amorphous and displays a glass transition temperature of 114 °C. The optical properties of the polymer were investigated by UV-visible absorption and photoluminescence spectroscopies. Its thin film showed a blue photoluminescence with a narrow emission spectrum. A high photoluminescence quantum efficiency of about 83% was determined in dilute solution. From the cyclic voltammetry analysis, the electrochemical bandgap was estimated to be 3.08 eV. A single-layer diode device of the configuration indium-tin oxide/ BPAF-PPV/aluminium has been fabricated and has a relatively low turn-on voltage of 3.0 V.

Synthesis, characterization and optical properties of distyrylanthracene-based polymers

Distyryl- and nitrodistyrylanthracene-based polymers (P1 and P2, respectively) have been synthesized and characterized. The polymers are fully soluble in common organic solvents and have number-average molecular weights of 18 570 and 23 480 g mol−1 for P1 and P2, respectively. The optical properties of the polymers were investigated by UV-visible absorption and photoluminescence spectroscopies. The optical gaps were estimated from the absorption-onsets of the polymer films; their values were 2.79, 2.75 eV for P1 and P2, respectively. A blue photoluminescence was observed in dilute solution. In solid thin film, Π–Π interactions influence the optical properties, and red-shifted photoluminescence spectra were obtained; a green emission (573 nm) for P1 and an orange one (605 nm) for P2 were observed. The HOMO and LUMO levels were estimated using cyclic voltammetry analysis. Single-layer devices of the indium-tin oxide/polymer/aluminum configuration were fabricated and showed relatively low turn-on voltages (5.14 V for P1 and 5.00 V for P2).

New Semiconducting Poly(arylene sulfide)s: Synthesis, Characterization, and Optical Properties

New semiconducting soluble poly(arylene sulfide)s were synthesized by Wittig polycondensation. The arylene moieties consist of distyrylbiphenyl (P1) and distyrylbithiophene (P2) π-conjugated systems. The polymers are fully amorphous and show good thermal stability. The absorption and photoluminescence properties of the polymers were investigated. P1 film has an optical gap of 2.95 eV and exhibits green-blue fluorescence. P2 shows a longer effective conjugation length with a gap of 2.42 eV and emits in the orange region. The HOMO/LUMO energy levels were estimated by cyclic voltammetry measurements. Single-layer diodes were fabricated and show relatively low turn-on voltages.