<p>The power conversion efficiency of all-perovskite tandem solar cells is predominantly constrained by optical absorption losses, especially reflection losses. In this simulation study, we propose the optimization of a dual-interface serrated microstructure to mitigate these optical reflection losses in all-perovskite tandem solar cells. By adjusting the geometry of the periodic serrated structures at both the front interface and the back electrode, we enhance light absorption in the wide-bandgap perovskite layer and promote light scattering in the narrow-bandgap perovskite layer. The structural modification reduces the reflection-induced photocurrent density loss from 4.47 to 3.65&#xa0;mA&#xa0;cm⁻². It is expected to boost the efficiency of all-perovskite tandem solar cells to approximately 31.13%, representing a 3.41% increase. The dual-interface optimization effectively suppresses reflection losses and improves the overall photocurrent of all-perovskite tandem solar cells. These results offer a promising strategy for minimizing optical losses and enhancing device performance in all-perovskite tandem solar cells.</p> Graphical Abstract <p></p>