PV Goes Colorful: Printing and Color Technologies for Retrofitting Solar Modules

The aesthetic integration of photovoltaics into buildings and urban spaces is a key factor in unlocking untapped solar potential. In cities, on historic buildings, and for façades or balconies, conventional dark-colored PV modules often face acceptance issues. Despite the rapid expansion of photovoltaics in Germany, the potential for building-integrated (BIPV) and building-attached PV (BAPV) remains largely unused. Current standard modules are often unsuitable for architectural reasons, as they do not blend harmoniously into the built environment. Existing solutions for colored PV modules are either expensive, limited to standardized designs, or associated with significant efficiency losses. This creates a strong demand for customizable, efficient, and cost-effective PV modules that also consider recyclability.

The COLIPRI project aims to develop a retrofit solution for the individual color customization of commercially available PV modules. This solution should maintain high module efficiency (over 75% compared to unprinted reference modules) while ensuring recyclability. The approach combines cost-effective standard modules with printed front glass or films that can be produced independently of mass manufacturing and retrofitted without damage.

The technical focus is on innovative ceramic colors and digital printing processes. Glass-ceramic color matrices are intended to provide high reliability and long-term stability, while spectrally selective pigments – including ceramic interference colors – minimize efficiency losses. Additionally, new printing raster concepts are being developed to reduce coverage and absorption, further optimizing the energy yield of colored modules. In parallel, lamination and alternative assembly processes for glass, thin glass, and polymer films are being investigated for applications such as façades, roofs, and balconies.

Fraunhofer CSP is responsible for the design and evaluation of these colored retrofit solutions, developing efficiency-optimized printing rasters and optical layer stacks, creating high-resolution datasets, and establishing measurement methods and test specimens. A simulation tool will enable rapid estimation of performance losses. This work lays the foundation for cost-effective, design-flexible PV modules for urban environments, promoting acceptance and accelerating the expansion of solar energy.