Solar panels are not known for their aesthetics, and this is one of the reasons why there is resistance to their adoption.
Conventional panels have to be dark to absorb maximum light. But they do not look good on urban infrastructure. Designers have been looking for ways around this without sacrificing output.
A new kind of colored solar cell is inspired by blue bird feathers. And it means more than 19 percent efficiency in generation.
How to leverage biological nanostructures that scatter wavelengths
This research was led by engineering and materials science researchers at Shanghai Jiao Tong University, in collaboration with The Hong Kong Polytechnic University (PolyU).
Their method involves the replication of biological nanostructures, and their latest result is a sky blue panel.
These surfaces were inspired by natural bird biology. The technology selectively reflects a narrow band of visible light to produce color while transmitting most of the remaining solar spectrum to the underlying cells with minimal absorption.
The blue color of bird feathers does not come from any pigment or dye. It is a structural coloration created by a network of microscopic keratin pores and air pockets.
The structure at the microscopic level has a quasi-ordered spatial arrangement that features uniform distances between immediate neighbors on one level but lacks a repeating, geometric pattern when looking at the bigger picture.
This formation interacts with sunlight. When light reaches the feather, blue wavelengths are scattered in all directions by the nanostructure.
The process is called constructive optical interference.
The pattern also allows other forms of visible and near-infrared light to penetrate without much of it being absorbed. This blue shade never fades or degrades under exposure to sunlight, which is important for application to solar energy systems.
Engineers have learned that chemical dyes absorb certain frequencies of light, and those photons do not reach the layer responsible for photovoltaics.
However, by copying the quasi-ordered physical structure of a blue feather, researchers came up with a coating that reflects color wavelengths but allows power to be generated at the same time.
A matrix across the panel surface that targets one color
Researchers had to synthesize self-assembling nanostructures to copy the natural structure of a feather. The result was a thin photonic layer with submicron particles arranged into a quasi-ordered matrix to be layered over the surface of the panel.
The panel covering works as an optical filter. It only reflects certain light bands outward, which humans see as sky blue.
What is important is that the coating does not absorb unreflected light. The photons that do not fall into the narrow blue band of reflection are able to pass through the film without much lost to scattering.
Optical testing showed that the structural color layer maintains high broad-spectrum transparency across harvestable solar wavelengths.
Laboratory measurements confirmed that the non-absorbing photonic structure preserves light intensity across the red and near-infrared spectrums, where solar cells generate substantial current.
By directing unreflected photons into the absorber below, the cell generates electrical power efficiently.
The bio-inspired coating operates without chemical pigments, preventing thermal degradation over time.
Photovoltaic efficiency results and architectural applications
Integrating structural coloration into solar cells typically carries a steep performance penalty. Conventional color treatments often cut overall energy conversion efficiency by several percentage points due to optical absorption and backscattering.
In experimental testing, solar cells featuring the bio-inspired photonic coating achieved a power conversion efficiency exceeding 19 percent.
This high performance proves that structural color can be applied to solar modules without severe efficiency losses.
Because the quasi-ordered nanostructure scatters only the specific blue wavelengths needed for visual appearance, the vast majority of incoming solar energy reaches the active cell layer.
Strong practical potential for building-integrated photovoltaics
Architects can incorporate these aesthetically pleasing blue panels into building facades, urban roofs, and exterior glass without the stark visual contrast of traditional dark silicon modules.
Future work will focus on scaling the nano-fabrication process for mass production and testing long-term weather durability under outdoor environmental conditions.
By combining biological optics with semiconductor engineering, the study demonstrates that renewable energy infrastructure can achieve visual appeal while maintaining high electrical output.
The full study can be read here: Li, Z., Ma, T., Chen, Y., Li, S., Dai, Y., Zhang, D., … & Yan, J. (2025). Structural coloring of solar photovoltaics with quasi-ordered photonic pigments. Nexus, 2(4).
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