NOVELTY - A photovoltaic module backsheet (B1) comprises: a polyester film having opposite first and second surfaces, and first and second fluoropolymer coatings on the first and second surfaces of the polyester film, respectively. The first and second fluoropolymer coatings comprise fluoropolymer selected from homopolymers and copolymers of vinyl fluoride and homopolymers and copolymers of vinylidene fluoride polymer blended with compatible adhesive polymer comprising a backbone that is compatible with fluoropolymer and pendant functional groups.    USE - As a photovoltaic module backsheet useful in a photovoltaic module (claimed), useful for photovoltaic cells or solar cells for producing electrical energy from sunlight.    ADVANTAGE - The fluoropolymer coated polymer film can be produced with fewer overall processing steps than manufacturing laminates with preformed fluoropolymer films while providing strong adhesion to the substrate and good durability to the fluoropolymer coated substrate. The fluoropolymer in the form of a coating enables thinner fluoropolymer layers if desired to save cost. Employing fluoropolymer coatings also enables the incorporation of additives into the fluoropolymer layer tailored to the intended use of the fluoropolymer coated film, e.g. fillers which improve barrier properties.    DETAILED DESCRIPTION - A photovoltaic module backsheet (B1) comprises: a polyester film having opposite first and second surfaces, and first and second fluoropolymer coatings on the first and second surfaces of the polyester film, respectively. The first and second fluoropolymer coatings comprise fluoropolymer selected from homopolymers and copolymers of vinyl fluoride and homopolymers and copolymers of vinylidene fluoride polymer blended with compatible adhesive polymer comprising a backbone that is compatible with the fluoropolymer and pendant functional groups selected from carboxylic acid, sulfonic acid, aziridine, anhydride, amine, isocyanate, melamine, epoxy, and/or hydroxy groups. The first and second surfaces of the polyester film comprise functional groups on each surface that interact with the pendant functional groups of the compatible adhesive polymer in the first and second fluoropolymer coatings to promote bonding of the fluoropolymer coatings to the respective first and second surfaces of the polyester film. An INDEPENDENT CLAIM is included for a photovoltaic module comprising: photovoltaic cells; an encapsulating layer on the photovoltaic cells; and the backsheet (B1) adhered to the encapsulating layer.