New soluble anthracene-based polymer for opto-electronic applications

A new anthracene-based polymer containing the isosorbide group in the side chain (PPVIs-An) has been synthesized via Wittig reaction. The polymer is soluble in common organic solvents and shows good film-forming abilities. The macromolecular structure was characterized by NMR and FT-IR spectroscopies. This organic material was investigated by differential scanning calorimetry and thermogravimetric analysis and showed an amorphous behavior with a T (g) of 48 A degrees C. The surface property of the PPVIs-An film was analyzed by contact angle and by atomic force microscopy. The optical properties of this organic semi-conductor were investigated by UV-Visible absorption and photoluminescence spectroscopies. The polymer exhibits a blue fluorescence in dilute solution and a green emission in thin film. The introduction of the polar isosorbide groups shown to improve the PL intensity, and a quantum yield of 72 % was obtained. The absence of pi-pi interaction between the chromophore units in polymer thin layer at fundamental electronic state was observed, due to the presence of steric repulsions between anthracene and isosorbide groups. The HOMO-LUMO energy levels were determined by cyclic voltammetry. An ITO/PPVIs-An/Al single-layer device was elaborated and investigated using current-voltage measurements which show a turn-on voltage of 5.3 V. The conduction mechanism seems to be a space-charge-limited current with exponential trap distribution at high applied bias voltage. The electrical transport properties of this device were studied as a function of frequency (100 Hz-10 MHz) and applied bias in impedance spectroscopy analyses.