A method of fabricating a flexible photovoltaic film cell with an iron diffusion barrier layer. The method includes: providing a foil substrate including iron; forming an iron diffusion barrier layer on the foil substrate, where the iron diffusion barrier layer prevents the iron from diffusing; forming an electrode layer on the iron diffusion barrier layer; and forming at least one light absorber layer on the electrode layer. A flexible photovoltaic film cell is also provided, which cell includes: a foil substrate including iron; an iron diffusion barrier layer formed on the foil substrate to prevent the iron from diffusing; an electrode layer formed on the iron diffusion barrier layer; and at least one light absorber layer formed on the electrode layer.