Building-Integrated Photovoltaics (BIPV) are increasingly recognized as a key technology for accelerating urban decarbonization. However, one of the main barriers to their widespread adoption remains the challenge of balancing energy performance with architectural aesthetics, particularly in visually sensitive urban and historic environments.
Qithin Heritace project, ZH srl explore an innovative perception-driven approach to colored photovoltaic modules based on discrete micro-pattern printing.
Traditional methods used to color PV modules often rely on uniform pigment coatings, which can significantly reduce solar energy transmission and overall module efficiency. The new approach draws inspiration from halftoning techniques used in digital printing, where color is created through the distribution of microscopic dots rather than continuous layers.
Example of monochromatic halftoning (Stulik & Kaplan, 2013)
By applying carefully designed ceramic microdot patterns onto the front glass of photovoltaic modules, the researchers achieved a visually uniform colored appearance at typical viewing distances while maintaining greater optical transparency. This strategy allows more sunlight to reach the solar cells, potentially reducing efficiency losses associated with conventional coloring technologies.
The study focused on how the human visual system integrates small discrete elements into a continuous color field. Using principles derived from visual acuity and halftone imaging, the team developed a library of eight parametric pattern configurations with surface coverage ranging from 10% to 50%.
Different geometries were tested, including:
Each configuration was designed to optimize the balance between visual homogeneity and light transmission.
The patterns were manufactured using industrial digital ceramic printing technology and laminated with black monocrystalline photovoltaic cells. Three architectural color palettes were selected:
In addition, selected samples were produced using different glass textures, including satin and fluted finishes, to evaluate the influence of surface treatment on color perception and light diffusion.
The experimental assessment revealed several important insights:
Perhaps most importantly, the study confirmed that aesthetic integration can be enhanced without relying on fully opaque color layers, opening new opportunities for energy-efficient colored BIPV systems.
While the current research focused primarily on visual and optical performance, future work will include detailed electrical characterization of the prototypes to quantify the impact of pattern geometry, color selection, and glass finishing on energy generation.
The research was funded under the Horizon Europe project HeriTACE (Grant Agreement No. 101138672).