Modelling of Contact and Adhesion at Interfaces in Bulk Heterojunction Solar Cells

Edmond, N.Y. Doumon (2011-12-15)


The study of the structures and properties of organic materials for organic photovoltaic (OPV) applications and their interrelationships is a rapidly growing field of research, involving interdisciplinary efforts at the frontiers of chemistry, solid state physics and materials science. These materials differ from the better-understood silicon solar cell based materials by the lack of long range three-dimensional translational periodicity in their atomic arrangements and also by their layered structures but are of important use in electronics, the medical fields, defense and aerospace etc. This study is concerned with bulk heterojunction (BHJ) solar cells, a class of organic photovoltaic (OPV) solar cells. We present a review of the state-of-the-art in the theoretical study of the structures of such solar cells. The topics covered include theory of semiconductors; the physics of solar cells; the structure, the properties and the nature of the organic materials for use in solar cells and the modeling of effects of contacts and adhesion at the interfaces of the layers of such devices. Our results showed that the presence of particles such as dust affect the performance of the devices. It creates voids at the interfaces of the device, resulting in reduction in contact length. It is also observed based on the modeling that the void’s length increases with increasing Young’s modulus of the layers while it decreases with increasing adhesion or increasing pressure due to lamination. This in turn, affects the contact length in the reverse way.