Structural Colored Planar Multilayers with Minimal Angular Color Dependence for Building Integrated Photovoltaics

The societal acceptance of building integrated photovoltaics (BIPV) is strongly linked to their visual appearance. In this regard, efforts have been devoted to the design of colored photovoltaic modules that can be esthetically blended into the roofs and façades of buildings. Distributed Bragg reflectors (DBRs), periodically intercalating nonabsorbing dielectric materials with contrasting refractive indices, are one of the most promising technologies currently explored to produce a broad range of vivid structural colors with minimal optical losses. However, DBRs usually exhibit strong color variation with respect to the angles of incident and reflected light, which is undesirable for BIPV applications. To minimize such iridescence, while avoiding the increased design complexity associated with the currently implemented textured substrates, here we developed an alternative approach, relying on an optimization‐based inverse design methodology, to identify nontrivial planar nanometer‐thin layer configurations capable of reproducing different target colors on demand with low angular color dependence. As we demonstrate, these optimized structures consistently outperform the conventional periodic DBRs, meeting the target colors with minimal angular variations in hue, regardless of the color selected, and with very low effect on the photovoltaic performance. Therefore, the proposed approach constitutes a promising route for the design of next‐generation colored BIPV.