Structured interference layer systems for the color design of integrated PV systems

PV plays a major role in the global decarbonization of energy systems. Especially colored modules show great potential in the building and mobility sector as they can increase the acceptance of PV applications by overcoming previous design or monument protection limitations. MorphoColorTM [1] enables aesthetically pleasing PV while maintaining high efficiency. Inspired by the Morpho butterfly effect [2, 3] and described by Bläsi et al. [4], MorphoColorTM basically consists of an interference layer system on the inside of a structured PV module cover glass, optimized for high color saturation and color stability by using a higher harmonic reflection order and a high average refractive index. We present our work on the optical simulation of these layer-structure systems by means of ray tracing and compare the results with gonio-spectrophotometric measurements. We observe good agreement and can describe and visualize the optical properties of the real systems well. A model-based comparison of possible module configurations further shows a clear advantage of a structured layer system compared to planar interference layers in combination with a scattering structure on the front side of the glass. When viewed from different angles, the MorphoColorTM approach results in a significantly more homogeneous appearance. Structuring of the front interface can optionally be added for an anti-glare effect but has no significant influence on the angular spread of the color appearance. In addition to the described simulation results, we present a new demo façade installation with an area of about 180m². In addition, a selection of possible colors is presented on the basis of large 1.5m² modules. The modules show a very angular stable and homogeneous color appearance and have an efficiency of 94% (red and green) or 96% (blue) relative to a black module.