The precise stoichiometric ratio of lead halide and organic ammonium salts is a fundamental yet unresolved scientific challenge in perovskite solar cells (PSCs). Conventional deposition techniques fail to establish a definitive structure-performance relationship due to limitations in quantitative control, leading to inconsistent film quality and ambiguous reaction pathways. In this work, a precise quantitative deposition approach using drop-on-demand inkjet printing to systematically investigate the impact of organic salt deposition surface density on PSC performance is developed. The findings reveal that the deposition amount significantly affects the morphology, composition, and crystallinity of the perovskite films, influencing the overall device performance. Low deposition surface densities below 22 µg cm