A transmission line model for the optical simulation of multilayer structures and its application for oblique illumination of an organic solar cell with anisotropic extinction coefficient

A transmission line model for the calculation of optical interference phenomena in dielectric multilayered structures is adopted as an alternative option to the transfer matrix model (TMM). The method is based on the transmission line theory and is exact, easy to implement and uses closed iterative forms instead of the TMMs matrix formalism. The proposed model has been appropriately modified and then applied for performance evaluation of a typical organic photovoltaic device under inclined illumination. Optical field distribution, short-circuit photocurrent and reflectivity have been calculated under different angles of light incidence. The theoretical simulations have been discussed and compared with experimental photocurrent measurements, while the influence of the photoactive layer thickness on the device efficiency has been evaluated for different angles of light incidence, taking into account its extinction coefficient anisotropy.