The fabrication and characterization of a novel tri-layer piezoelectric nanogenerator (PNG) based on poly(vinylidene fluoride) (PVDF), barium titanate (BTO), and surface-modifiedn-type graphene (n-Gr) have been investigated. The n-Gr, with its majority of negative charge carriers, plays a vital role in enhancing the energy-harv.esting performance by aligning the dipoles in one direction. The tri-layer structure obtains by stacking two layers of PVDF-BTO nanocomposite films, one on each side of the n-Gr layer. The fabricated tri-layer PNG shows a maximum output voltage of 10V (pk-pk) along with a current of 2.5 mu A(pk-pk) at an applied force of 2 N. Furthermore, the PNG Exhibits 5.8 mu W instantaneous power at 1 MO load resistance. Moreover, the fabricated device demonstrated good stability even after 1000 pressing releasing cycles. This novel tri-layer PNG structure can opens a promising avenue for future piezoelectric generating technologies. (C) 2017 Elsevier B.V. All rights reserved.