Investigation on photocurrent polarity of a bulk heterojunction organic photovoltaic device using a ferroelectric thin film

Abstract

The ferroelectric thin film of lead magnesium niobate-lead titanate (PMN-PT) was fabricated and characterized using UV-Vis transmission spectroscopy, X-ray diffraction (XRD), and atomic force microscopy (AFM). To determine the photocurrent properties of the bulk hetero junction organic blend film a photovoltaic device with the structure of tin indium oxide (ITO)/PMN-PT/organic blend film /aluminum (Al)was fabricated. Under modulated laser irradiation the amplitude and polarity of the transient photocurrent varied with the bias voltage, which shows that the photocurrent polarity of a conventional bulk hetero junction organic photovoltaic device is determined by the internal electric field that is induced by the difference between the work function of the anode and cathode electrodes. A new method is proposed for investigating the photocurrent properties of bulk hetero junction organic photovoltaic devices. © Editorial office of Acta Physico-Chimica Sinica.