This study demonstrates the performance improvement of ultrasonic spray deposited bulk heterojunction type polymer solar cells through droplet boundary reduction assisted by acoustic substrate vibration of varying frequencies between 0–20 kHz. The optimum performance was achieved at 15 kHz of applied frequency, where ∼68% improvement in short-circuit current density and ∼85% improvement in overall cell efficiency were observed compared to the reference devices fabricated on stationary substrates. The performance enhancement is mainly attributed to the improved film morphology due to uniform and homogenous droplet spreading and coalescence under the influence of acoustic vibration. Systematic improvement was observed until 15 kHz when smooth films with significantly reduced droplet boundaries were observed with surface roughness around 10 nm only. However, beyond this point, higher frequencies were found to have detrimental effect on film formation. Significant improvement was observed for every cell parameter for 15 kHz samples. Almost ∼16% enhancement in carrier generation rate and ∼46% enhancement in exciton dissociation probability were observed, as estimated from the photo-current analysis. Urbach energy estimation reveals that the films, prepared at 15 kHz substrate vibration, forms less amount of band edge localized defect states (Eu (no vibration) = 161 meV and Eu (15 kHz) = 120 meV), resulting into reduced non-radiative recombination and better performances. The presented approach opens up new pathways for uniform and scalable thin film growth through acoustic substrate vibration assisted ultrasonic spray deposition technique, which would be beneficial for large scale industrial organic photovoltaic production.