Abstract

Urban architects increasingly seek solar windows that deliver both energy generation and aesthetic value. However, existing color-engineering strategies rely on absorptive metal layers or lack control over the achievable colors. Here, we present a modelling-guided inverse design strategy that integrates an all-dielectric (ZnS/MgF2) multilayer into semitransparent perovskite photovoltaics, enabling user-defined colors with minimal spectral loss.

Leveraging an active learning algorithm, we mapped the attainable color gamut for ZnS/MgF2-coated devices with distinct perovskite absorber thicknesses and average visible transmittance (AVT) values. As a representative case, a device with a 110 nm-thick absorber on glass or polyethylene terephthalate (PET), initially exhibiting a reddish-brown tint, was transformed into vivid cyan using a 600 nm-thick all-dielectric multilayer.

This tuning retained high AVT—6.5% on glass and 5.3% on PET—while enhancing power conversion efficiency by 20.9% and 10.4%, respectively. Real-world imaging confirmed enhanced aesthetics with see-through visibility, underscoring the practical potential of the inverse-design framework. Moreover, this approach is readily transferable to other thin film photovoltaics, providing a versatile route toward color customizable, transmittance-tunable, and high-efficiency solar windows for buildings, vehicles, and wearable electronics.