Strategies for efficient and stable colored perovskite module with Bragg reflector and luminescent down-shifting layer

Colored perovskite modules (CPMs) offer a promising solution to the aesthetic limitations of building-integrated photovoltaics (BIPVs). Here, we report the theoretical efficiencies of CPMs incorporating either a Bragg reflector (BR) or a luminescent down-shifting layer (LDS). Results indicate that CPMs with LDSs outperform those with BRs for colors with L∗ coordinates under 70 in the CIELAB color space, attributed to the use of high-energy photons in LDSs, where the internal quantum efficiency is usually low. Conversely, the BR is more effective for colors with L∗ coordinates exceeding 85, as these colors require a narrower reflectance bandwidth for BR than the emission bandwidth of LDS. Additionally, the analysis of trap-assisted recombination and energetic disorder reinforces the potential of CPMs in terms of their stability. These findings emphasize the necessity for distinct color-generation strategies based on color coordinates, providing valuable guidance for designing CPMs that balance the performance and aesthetics of BIPVs.