Papers by Author: Bandar Ali Al-Asbahi

Abstract: The solution of poly [(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo [2,1,3] thiadiazol-4,8-diyl)] (F8BT) F8BT/TiO₂ nanocomposites were prepared using solution blending methods. The TiO₂ contents were fixed between 0 wt% - 35 wt%. Then, the solutions were spin coated at 1000 rpm for 30 s onto glass substrates to form thin film samples. The optical properties of the nanocomposites were determined using UV-Vis spectroscopy and photoluminescence spectroscopy. The absorption properties of the thin film increased due to existence of intermediate energy band which lead to higher space charge regions for electron insertion. Besides that, the λ_max for absorption and emission spectrum were systematically shifted due to incorporation of TiO₂ NPs indicating an interaction between nanoparticles and polymer matrix. Furthermore, the intensity of the emission spectrum were enhanced in the presence of TiO₂ NPs. This is due to the existence of TiO₂ NPs which trapped more electrons at the interface F8BT/TiO₂, resulted production of higher number of exciton formation in the nanocomposirte samples.

Abstract: The effect of laser dye (Fluorol 7GA) content on the optoelectronic properties of Poly ( 9,9'-di-n-octylfluorenyl-2.7-diyl) conjugated polymer (PFO) based OLEDs has been investigated. The PFO/Fluorol 7GA hybrids with weight ratios between 0.1 and 5 wt. % were prepared using the solution blending method. The blends were deposited on ITO (Indium Tin Oxide) substrate using spin-coating technique. Thin layer of aluminum was deposited on top of the films to act as electrode. Absorption and photoluminescence techniques were used to investigate the energy transfer in the blend. The device performance was investigated in terms of electroluminescence, luminance, luminance efficiency and color measurements. The Förster energy transfer occurred in the blends as evidence from optical spectroscopy and average distance between donor and acceptor molecules. The optimum ratio was 0.5 wt. % where highest enhancement in OLEDs performance was observed. These were attributed to the synchronize effect of efficient energy transfer from PFO to Fluorol 7GA and carrier trapping processes.