Harvesting human motion or blue energy with mechanical energy harvester is well-thought as an efficient and robust procedure nowadays. Besides, bacterial fouling to the harvester possesses serious alarms for implantation in human body or installation in water system. Here, for the first time, an antibacterial piezo-composite based on polydimethylsiloxane-zinc stannate@silver oxide (PDMS-ZnSnO3@Ag2O) has been proposed. The surface adornment of n-type ZnSnO3 nanocubes (NCs) with p-type Ag2O finished an effective bulk n-p heterojunction-based composite for energy harvesting and biological activities. The maximum output voltage, current, and power density of the made-up piezoelectric nanogenerator (PENG) are ~36 V, ~1.9 µA, and ~11.4 µW/cm2, respectively, under finger tapping. The energy conversion efficiency of the PENG assessed during a capacitor (10 µF) charging is ~2.49 %, which is superior to the earlier reports. Moreover, a gram-negative bacterium model (Pseudomonas aeruginosa) has been selected for the biofilm formation study. Biofilm assay, antimetabolite, and intracellular ROS studies clearly reveal that the piezo-composite comprising Ag2O is an excellent material for antibacterial activities.