Familiarization With Organic Photo-voltaic Cell and Simulation of Single Layer and Multi-layer Active Cell for Improving Efficiency and Fill Factor

Abstract

Organic photovoltaic has been developed for more than 30 years, however, within the last decade the research field gained considerable in momentum. The amount of solar energy lighting up Earth's land mass every year is nearly 3,000 times the total amount of annual human energy use. But to compete with energy from fossil fuels, photovoltaic devices must convert sunlight to electricity with a certain measure of efficiency. For polymer-based organic photovoltaic cells, which are far less expensive to manufacture than silicon-based solar cells, scientists have long believed that the key to high efficiencies rests in the purity of the polymer/organic cell's two domains -- acceptor and donor. The basic principle of organic solar cells is to place layer(s) of organic electronic material between two metallic conductors of two different work functions. This difference of work function sets up an electric field within the organic layer(s) which when absorbs light, causes the excited electrons to be pushed towards positive electrode and holes towards negative electrode. This thesis has been based on an optimized two-layer organic solar cell which aims to increase the photon absorption by increasing the interface area between donor and acceptor levels. This report summarizes the latest advances in the interfacial layers for bi-layer OSCs (including bulk hetero-junction photovoltaic cells. Finally, a brief summary and some perspectives about the current challenges and opportunities have been presented about this interesting area of research.