Charicteristic of a novel optoelectronic polymer and related device fabrication

Abstract

In this paper a preliminary investigation of a novel optoelectronic polymer, poly (p-phenylene N-4-n-butylphenyl-N,N-bis-4-vinylenephenylamine) (PNB), is reported. A single layer structure of ITO/PNB/Al was prepared via spin-coating of PNB solution as a thin film on the top of an ITO substrate, while aluminum top electrode was vacuum evaporated. Dark current-voltage characteristics of this device showed a typical rectifying behaviour. Photovoltaic response under a monochromatic illumination at 420 nm was observed, with an open circuit voltage of 0.3 V and fill factor of 0.21. Spectral response and optical absorption were found to be matched well. It was also discovered that the device showed a green electroluminescent emission at a forward bias. Turn-on voltage of the device was about 6 V and light output about 22.6 nW at a forward bias of 10 V. The work demonstrated that the PNB material might possess dual exciton sites resulting in a competition for excitons to be either separated or recombined. Both effects were associated with each other, which limited the photovoltaic or electroluminescence to some degrees.