Abstract
Two new anthracene derivatives were characterized to improve the optoelectronic properties of pi-conjugated anthracene polymers. The optical properties of the polymers were investigated by UV-visible absorption and photoluminescence (PL) spectroscopy. The energy bandgaps of anthracene-based polyether thin films were in the range 2.8-2.97 eV. Green emission (504 nm) was observed for anthracene/bisphenol A (An-BPA) and green-yellow emission (563 nm) for anthracene/fluorinated bisphenol A. (An-BPAF) Organic diodes formed by sandwiching anthracene layers between indium-tin oxide (ITO) and aluminum contacts were characterized. The dc electrical properties of ITO/anthracene derivatives/Al diodes were studied using current-voltage measurements and showed ohmic behavior at low voltage. The conduction mechanism seems to be a space-charge-limited current with exponential trap distribution at high applied bias voltage. The ac electrical transport of the anthracene derivatives was studied as a function of frequency (100 Hz-10 MHz) and applied bias in impedance spectroscopy analyses. We interpreted Cole-Cole plots in terms of the equivalent circuit model as a. single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed. The conduction mechanism revealed by I-V characteristics is in agreement with the impedance spectroscopy results. (C) 2013 Elsevier Ltd. All rights reserved.