Building-Integrated Photovoltaics (BIPV) are no longer just hidden technologies as construction materials. They’ve become canvases—adding color, texture, and personality to buildings while still converting sunlight into clean electricity. But as solar panels evolve into design elements, one big question remains: can we make them beautiful and efficient?

The Science of Color and Efficiency

At the heart of every BIPV module is a delicate balancing act: allowing sufficient sunlight to reach the photovoltaic cell while creating a surface that complements the building’s aesthetic.

Absorptive (Pigment-Based) Coloring:
Pigments are the most straightforward way to add color, but they come with a price. They absorb parts of the solar spectrum, blocking valuable light before it even reaches the solar cell. Research has shown that modules with pigment-based multilayer coatings can lose 16–24% efficiency, and bright white coatings can cut performance by almost 40% compared to uncolored modules

Structural (Interference-Based) Coloring:
A smarter approach is structural coloring. Instead of using pigments, it employs thin-film interference layers to reflect only narrow bands of light, while allowing the rest to pass through. That means the cell can still absorb most of the usable spectrum. Studies show that modules with structural colors can keep efficiency losses below 10% compared to standard black panels.

As Dr. N. Martín-Chivelet of CIEMAT explains, “with structural colors, it’s possible to combine vivid, stable aesthetics across wide viewing angles with minimal power losses”

Where Color Matters Most

The effect of coloring depends a lot on where in the module the change is made.

• Behind the PV Cell (encapsulants, interlayers, back cover):
  Adjustments here usually cause minimal or no efficiency losses, because the sunlight has already gone through the photovoltaic cell.
• In Front of the PV Cell (glass, front coatings):
  This is where it really matters. Any pigments or coatings here directly control how much light reaches the solar cell, and the losses can vary depending on the color. A strong example is the RINGS-BIPV demonstration façade in Spain. There, researchers found:
  • Green modules reduced efficiency by only 4%,
  • Terracotta modules lost about 15%,
  • Anthracite modules performed almost the same as black modules

As Martín-Chivelet notes, “the losses are very color-dependent; lighter shades tend to reflect more sunlight, which translates into lower electrical output.”

Even more exciting, Fraunhofer ISE developed a bionic surface inspired by the Morpho butterfly’s wing, achieving vivid structural colors with only a ~7% efficiency reduction, while also cutting glare

Innovative Techniques for Colored BIPV

To balance looks with performance, scientists and manufacturers are experimenting with new techniques:

• Anti-Reflection (AR) Coatings:
  Adjusting the thickness of AR coatings can change how a module appears in color, while still keeping sunlight transmission high. Silicon nitride and titanium oxide are the most common materials, and efficiency impacts usually range between 8–20% depending on the shade.
• Nano-Structured Surfaces:
  Inspired by nature, nano-textured coatings can produce strong, iridescent colors without pigments—similar to the shimmer on a butterfly’s wings or a peacock feather.
• Semi-Transparent and Colored Solar Glass:
  Some innovations go beyond opaque panels. Semi-transparent colored solar glass lets architects design façades and skylights that generate electricity while shaping how natural light enters indoor spaces.

Testing and Real-World Performance

Testing is key to making sure colored BIPV modules don’t just look good at launch but keep performing for decades.

• Spectral Response Analysis: Measures how different colors affect which wavelengths of light get absorbed.
• Outdoor Demonstration Projects: Like the CIEMAT façade in Spain, which reveals how modules actually behave in real weather conditions.
• Durability and Stress Tests: Confirm whether coatings keep their color and efficiency after long exposure to UV radiation, heat, and moisture.
• Angle of Incidence Studies: Show how some colors lose more efficiency when the sun hits at sharper angles, with losses up to 5% extra, depending on the hue.

Examples of AGC Planibel Coloured: Grey, dark-grey, purple, dark blue, azur, green, and
bronze.

The Future of Colored BIPV

Coloured BIPV is more than a technology—it’s a design revolution. It gives architects the freedom to blend solar façades into heritage settings with earthy terracotta, integrate greens into park-side projects, or showcase bold, futuristic looks with metallic or iridescent tones.

With structural coloring advancing rapidly, the old compromise between beauty and efficiency is fading. Instead, buildings can now tell their own story—through color, design, and energy—without giving up performance.