<p>In perovskite solar cells, the thickness and refractive index of each layer are critical factors that determine light absorption, thereby directly influencing overall device performance. However, systematic experimental evaluation of a wide range of structural parameters is impractical due to the large parameter space and the associated time and cost constraints. Therefore, optical simulation methods are widely used as essential tools for device design and optimization. However, the assumptions of perfectly flat structures in typical simulations can lead to discrepancies from real devices. In this study, we incorporate measured morphology into the optical model and investigate their influence on device absorption. We analyze how interfacial structure influences the optical response of perovskite solar cells. When interfacial roughness is included, the interference induced fluctuations observed in the planar model are reduced. Especially, bottom interface roughness plays a significant role in mitigating the optical interference originating from the front side. These results show that considering realistic device structures is essential for accurately understanding and designing high-efficiency perovskite solar cells.</p> Graphical abstract <p></p>