Investigation on structural, morphological, optical, and current-voltage characteristics of polyfluorene with dissimilar composition spin coated on ITO

Abstract

Different weight composition of polyfluorene (PFO) ((0.625 mg, 1.250 mg, and 2.500 mg) have been prepared and dissolved in toluene before spin coating on indium tin oxide (ITO) glass substrates. Post-deposition annealing was carried out to transform the wet film to solid film. High resolution X-ray diffraction analysis has detected the presence of broad diffraction peaks belonged to β-phase of PFO in all of the investigated samples. An onset of crystallization for the β-phase happened in the 2.500 mg PFO coated sample. Photoluminescence emission spectra of the β-phase was increased in intensity. Besides, a red shift happened due to an increase in energy transfer from glassy to β-phase, following an increase in conjugation length in the PFO backbone. The formation of crystalline β-phase and increased conjugation in the 2.500 mg PFO coated sample. Hence, the corresponding current-voltage characteristic showed that the highest current conduction has been perceived by the sample. A schematic diagram showing energy band diagram of the Al/PFO/ITO structure was presented and discussed in association with structural, morphological, and optical characteristics of the PFO films.