Organic PV cells have gained tremendous attention in recent years for its advantage of having tailored molecular properties and economic manufacturing process. Along with the rigorous and rapid researchesprogressing in the field of organic photovoltaic cells, accurate modelling of organic PV cells has gained extreme importance. Hence in this paper, modelling of organic solar photovoltaic cells based on an improved reverse double diode model is presented. Apart from all other complex mathematical models available in literature, the modelling is performed by introducing simple circuit equations. Furthermore, the model is highly capable of realizing the ideal and non-ideal current-voltage characteristics of an organic PV cell. The eight unknown parameters of the model are extracted using Genetic Algorithm(GA) and the extracted parameters are used to predict the I-V characteristics of a nav-100 organic solar cell. The main aim of this paper is to study the behaviour of organic solar cells and to realize an accurate PV model to replicate the exact I-V characteristics.