Model for Studies of Lateral Photovoltaic Effect in Polymeric Semiconductors

Abstract

We present here a discrete circuit spreading impedance network model for highly disordered semiconducting polymeric Schottky devices. Qualitative arguments are presented to correlate the parameters of the spreading function, which represents the network connectivity in the model, to the underlying morphology of the polymer. A detailed theoretical study of the lateral charge transport in organic Schottky devices is carried out using the model. We observe and analyze the dependence of the lateral photovoltage (LPV) on the polymer morphology, incident power, material specific Schottky junction parameters and the modulation frequency. The model is shown to account for a variety of experimental observations on poly-(3-hexylthiophene) and poly-[2-${hbox {methoxy}}$,5-(2-${hbox {ethylhexoxy}})$-1, 4- ${hbox {phenylene~vinylene}}$]-based position sensitive devices, while being physically transparent and computationally efficient. Using the model, we highlight those parameter regimes that would be optimal for position sensing applications.