Lead-free materials with superior piezoelectric properties are gaining much interest due to their high performance and increased long-term sustainability. In this context, bismuth-based ternary oxides exhibit perovskite crystal structures with high piezoelectric coefficients and mechanical damping. Thus, in this work, we report a Bi2CuO4: Polydimethylsiloxane (BCO: PDMS) composite -based photoinduced-piezoelectric nanogenerator for harvesting weak mechanical vibrations which are abundant in the atmosphere. Notably, the BCO nanoparticles exhibit a highly crystalline tetragonal structure with 2D-nanoflake-like morphology providing a high surface area for the PENG applications. Further, the optical studies of BCO illustrate an enhanced absorption in the visible region with a bandgap of 2.5 eV. BCO: PDMS-based PENG displays a maximum open circuit voltage of 50 V and short circuit current of 300 nA upon application of 0.15 kgf vertical compressive force without any electrical poling. The PENG device exhibits an 18 % increment in output voltage upon illumination of visible light of 5 mW/cm2 intensity with superior photodetection properties. The obtained response can be attributed to the synergistic effect, i.e., the generation of exciton pairs upon illumination and separation of charge carriers due to the inbuilt piezoelectric field. Moreover, the PENG exhibits a distinct and accurate response for feeble and subtle frequencies in the range of 3–22 Hz such as atmospheric noise, and gravity hum noise. thus, proving the superior sensitivity. The fabricated PENG device displayed a stable response for 30 min of continuous vibration displaying superior cyclic stability. This work demonstrates a combination of perovskite crystalline material and PDMS leading to the development of high-performance piezoelectric nanogenerators with future scope in frequency detection systems for security and safety applications. © 2023 Elsevier B.V.