Abstract: The present invention relates to a composite film that is capable of converting mechanical energy to electrical energy. The film comprises a substrate and piezoelectric nanoparticles that are configured to form a plurality of pores. The present film is flexible and highly porous, providing high permittivity and beneficial porosity-mediated mechanical properties. When used in a piezoelectric nanogenerator (PNG), the film provides enlarged bulk film strain and reduced film impedance, resulting in a high efficiency PNG with increased output voltage and current as compared to known PNGs. A method of synthesizing the film is also described. The provided method is simple and cost-effective.