COMPUTER MODELING OF ORGANIC THIN-FILM SOLAR-CELLS .1. EXCITON MODEL OF PHOTOCURRENT GENERATION

A computer model was developed to simulate the generation of the photocurrent in two-layered pn-type organic solar cells. The model enables the calculation of the photocurrent in dependence on layer thicknesses, kind of dyes (exciton diffusion length, spectral absorption constants), and exposure. It could be shown that the optimal layer thicknesses in organic pn-type solar cells have to be relatively small (25 to 40 nm) due to the short exciton diffusion length in polycrystalline organic materials. The therefore limited performance of organic solar cells can be improved by alternative design, i.e., by inserted mixed dye layers for enlarged exciton dissociation efficiency.