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Figure showing the honeycomb-structured 3D PV design, the mechanical metamaterial support, and the light recapture mechanism. (Image Credit: Advanced Materials Technologies)
Although PV modules are useful, they have a flaw. They don’t retain all the captured sunlight, as reflected photons escape from the surface before being converted into electricity. Anti-reflection coatings and surface texturing don’t eliminate those losses, but they can reduce them. And there are other techniques to deal with this issue. In 2022, engineers sought inspiration from bees and developed a honeycomb-structured 3D photovoltaic module that redirects reflected sunlight toward solar cells.
The team’s module uses a 3D tetrahedron-like concave geometry assembled into a hexagonal honeycomb structure. Each honeycomb cell has six interconnected tetrahedron units with mechanical metamaterials supporting them. With this concave configuration, reflected and scattered light is redirected onto nearby solar cell surfaces. That makes the sunlight more likely to be absorbed and converted into electricity, a process that improves power production via enhanced light recapture.
To support the module’s complex geometry, the team added a mechanical metamaterial with a negative Poisson’s ratio. These materials expand laterally as tension is applied, unlike those that become thinner when stretched. This ensures the mechanical stress is more evenly distributed. Additionally, the photovoltaic module can flex and conform to curved surfaces while all the solar cells align.
Image showing the 3D photovoltaic module, its mechanical metamaterial framework, and the structural tests. (Image Credit: Advanced Materials Technologies)
Before fabricating the module, the team used computer simulations and optical ray-tracing analysis for geometry optimizations. They also observed how light moved through the 3D cavities. Afterward, they tested the finished prototypes against conventional flat photovoltaic modules to evaluate electrical output and mechanical performance.
During experiments, the geometry improved light capture. Compared to flat cells, tetrahedral units set at a 40-degree angle generated an 11% increase in short-circuit current. Meanwhile, those positioned at a 60-degree angle had a 39% increase. The team also tested the entire honeycomb module and discovered it generated roughly 28% more electricity than a flat photovoltaic module under controlled conditions. Performance results matched the team’s optical simulations. This suggests that enhanced light recaptured within the concave structure improved performance.
This technique could enable photovoltaic systems to be deployed in applications where standard flat modules aren’t practical, such as vehicles and curved surfaces. Improving energy collection through geometric design instead of new photovoltaic materials enables higher power output without changing the underlying solar cell technology.
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