We present a numerical optimization of organic and hybrid multijunction solar cell devices , using an integrated optoelectronic device simulation approach that captures the essential properties of the complex multilayer structures, such as, light scattering at both macroscopic and rough thin film textures, resonator effects in coherent stacks, and the impact of organic interface properties for the design of efficient recombination layers . The optimization capabilities of the numerical device simulation framework are illustrated in the examples of textured perovskite silicon and all organic tandem solar cells.