Efficiency limit analysis of organic solar cells: model simulation based on vanadyl phthalocyanine/C60 planar junction cell

The power-conversion-efficiency (PCE) limit was simulated for a planar vanadyl phthalocyanine (VOPc)/C60 heterojunction model device. On the basis of the transfer matrix method and exciton diffusion analysis, short-circuit current density (J sc) was simulated as a function of exciton diffusion length (L d). The model device was simulated to be operated in a wide wavelength range (300–950 nm). A large J sc up to 30 mA/cm2 was obtained at an L d of approximately 10 µm. On the basis of the estimated V oc values of 0.8–1.0 V, the PCE limit of the model device was calculated to be in the range of 17–22%, which is close to the reported results of thermodynamic analysis.