Semi-transparent organic photovoltaics (ST-OPVs) have emerged as a promising technology for aesthetic building-integrated photovoltaic (BIPV) applications, offering unique advantages in light transmittance, power generation, thermal shielding, and color tunability. However, achieving a synergistic balance between color quality, photovoltaic performance, transparency, and thermal insulation remains a critical challenge for practical architectural deployment.

Current ST-OPV devices often suffer from monotonous colors and limited functional integration. While colorful semi-transparent devices have been demonstrated, key parameters closely related to building energy efficiency—such as infrared rejection rate (IRR) and color rendering index (CRI)—are frequently overlooked in device optimization. Conventional colored PV structures relying on microcavities, distributed Bragg reflectors, or photonic crystals face inherent drawbacks and cannot achieve multifunctional integration while maintaining satisfactory color performance. Moreover, single-sided DMD electrode structures still depend on ITO-based electrodes, whose insufficient reflectance limits color performance and adaptability to semi-transparent building scenarios.

In a study published in Advanced Functional Materials, a joint research team led by Prof. LIU Xingyuan from the Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences, together with Prof. XIE Zhiyuan from the Changchun Institute of Applied Chemistry (CIAC) of the Chinese Academy of Sciences, proposed an innovative double-sided dielectric/metal/dielectric (DMD) architecture for programmable photovoltaic windows.

ZHANG Yu et al redesigned the fundamental ST-OPV architecture by engineering a strong, tunable Fabry–Pérot microcavity using double-sided DMD electrodes instead of appending optical modulators to conventional electrodes. This design creates independent control knobs for visible color, transmission spectra, and infrared reflection. Combined with a bottom MoO₃ annealing strategy to optimize the optoelectronic properties of the DMD electrode, the structure effectively decouples and simultaneously maximizes multiple key performance parameters.

The resulting devices achieve a broad sRGB color gamut—approximately twice that of ITO-based counterparts—with a high color rendering index up to 89.8. The optimized ST-OPV device demonstrates an impressive balance between aesthetic and functional performance: a power conversion efficiency (PCE) of 10.07%, an average visible transmittance (AVT) of 35.9%, and an outstanding infrared rejection rate of 91.59%, yielding a light utilization efficiency (LUE) of 3.62%. The ultrathin Ag layers combined with MoO₃ phase modulation provide sufficient reflectivity to establish well-defined F–P cavity modes while maintaining high visible transparency and competitive photovoltaic efficiency.

These programmable photovoltaic windows integrate wide-gamut color programmability, high color rendering, and outstanding thermal management capability, offering a promising strategy for multifunctional semi-transparent OPVs that meet the stringent requirements of aesthetic, energy-efficient building facades in the era of carbon neutrality.