The development of eco-friendly, strong, stretchable, and stable triboelectric nanogenerators (TENGs) is urgently needed to meet increasing energy demands. Moreover, using naturally available, sustainable materials and simple fabrication protocols is highly desirable for current industrial applications. Polyvinyl alcohol (PvOH) blended with modified chitosan (CN) films represents a promising alternative for harvesting high energy density via the contact-separation mechanism of TENGs. The PvOH–CN film forms a highly flexible, easily scalable membrane. When mechanically sand-blasted, the PvOH–CN biofilm (Sb-PvOH–CN) exhibits an increased surface area, enhancing its TENG output compared to the unmodified PvOH–CN film. Field-emission scanning electron microscopy (FE-SEM) revealed the surface morphology, while strong chemical interactions, particularly hydrogen bonding were observed within the PvOH–CN matrix. Importantly, the Sb-PvOH–CN biofilm achieves TENG outputs approximately two times higher than those of the pristine PvOH–CN biofilm, owing to its greater surface roughness and improved ion transport facilitated by ion exchange particularly in comparison with PTFE-based films. Furthermore, the Sb-PvOH–CN biofilm exhibits higher open-circuit voltage (Voc) and short-circuit current (Isc) than pristine CN, PvOH alone, and PvOH–CN films. The Sb-PvOH–CN surface efficiently generates charges via an electron-transfer mechanism in a vertical contact-separation mode, outperforming PTFE. Specifically, the Voc and Isc of the Sb-PvOH–CN TENG increase by up to 360 % and 4166 % over the CN TENG, 1009 % and 11,072 % over the PVA TENG, and 73 % and 109 % compared to pristine PvOH–CN TENG, respectively. These enhancements are attributed to the abundance of free electrons on the amine (–NH₂), hydroxyl (–OH) and O groups within the Sb-PvOH–CN film. The innovative Sb-PvOH–CN/PTFE TENG represents a strong, eco-friendly alternative for compact, high-performance energy-harvesting devices using contact-separation mode.