Solar-Enhancing Film
Smart Material Solutions (SMS) has developed Solar-Enhancing Films that increases solar panel efficiency by integrating nanoscale anti-reflective (AR) moth-eye structures with microscale light-trapping features that increase the path length of light inside the panel. The nanocoating also resists dust accumulation, an advantage in terrestrial, Lunar, and Martian environments.
SMS’s Solar-Enhancing Film has demonstrated efficiency gains for many technologies including amorphous silicon, crystalline silicon, organic, and multijunction GaAs solar cells. For example, the nanocoating yields up to 5% more current from multijunction solar cells at normal incidence and over 20% more current at 80° incidence compared to state-of-the-art AR-coated solar glass. Preliminary testing also confirms UV stability and abrasion resistance.
Panel without Nanocoating
Uncoated panels exhibit strong reflections, absorb less light, and are more susceptible to the buildup of dust, dirt, and grime that block incoming light
Panel with Nanocoating
Microscale light-trapping features increase optical path length, while nanoscale moth-eye structures reduce Fresnel reflections and decrease surface soiling
This technology was developed with SBIR funding from the US Army and Space Force, in collaboration with PowerFilm Solar, MicroLink Devices, and MicroContinuum, and was selected as a winner of the Army XTechSBIR CleanTech Competition.
Performance Enhancement
Efficiency Increase
The Solar-Enhancing Film provides similar relative efficiency gains across a wide range of solar technologies, including amorphous silicon, crystalline silicon, organic, and multijunction GaAs cells.
Efficiency increase of silicon cells due to nanocoating
As an example, we measured the efficiency of crystalline silicon solar cells encapsulated in PET by PowerFilm as a function of incidence angle using a solar simulator with an AM1.5G filter. SMS’s adhesive-backed retrofit film was then applied to the same cells, and the measurements were repeated. The plot on the right shows the increase in power conversion efficiency after applying the Solar-Enhancing Film.
These efficiency improvements were used to estimate increases in daily power output, summarized in the table below, assuming direct sunlight on a south-facing panel in the northern hemisphere on the equinox.
Percent increase in daily power output of silicon solar cells due to addition of SMS’s retrofit film
Dust Mitigation
Photo showing solar cells with no coating (left) and with SMS’s nanocoating (right) after dust exposure
The Solar-Enhancing Film also reduces the adhesion of dust, which can otherwise accumulate on solar panels and block a significant portion of the incoming light. In addition, nanofeatures can impart self-cleaning properties that make it easier for rain to remove any dust that has accumulated.
The photo on the left shows two PowerFilm amorphous silicon solar cells after dust exposure. The uncoated cell (left) exhibits substantial dust accumulation, while the nanocoated cell (right) remains largely free of dust, demonstrating the film’s dust-mitigation capability.
Suppression of Bright, Specular Reflections
Photo of a PowerFilm panel with reflection suppression due to SMS’s Solar-Enhancing Film on the top, right corner
SMS’s Solar-Enhancing Film also suppresses bright, specular reflections. The photo on the left shows sunlight reflecting off a flexible PowerFilm panel with our light-trapping nanocoating on the top, right corner of the panel. The nanocoating suppresses the bright reflection in this region.
Film Options
Film Types
SMS has developed two types of Solar-Enhancing Films, each with the ability to impart light-trapping, self-cleaning properties to solar panels:
Solar encapsulation film
Solar Encapsulation Film: Replaces the encapsulation film in existing manufacturing processes with a light-trapping, self-cleaning encapsulation film like the one pictured to the right.
Retrofit Film: Adhesive-backed film that can be added to existing panels to increase efficiency.
Nanopatterns
SMS has developed a variety of nanoscale and microscale features for its light-trapping films such as those described below.
Moth-Eye
Nanoscale features that decrease Fresnel reflections by creating a graded-refractive-index structure
Light-Trapping
Microscale features that bend light to increase its path length inside a panel
Can have a variety of shapes including bumps, pyramids, and cones
Hierarchical
Multiscale features that contain both nanoscale moth-eye features and microscale light-trapping features
Armor
Large microscale features that can be added to any pattern to mechanically protect moth-eye and/or light-trapping features
Next Steps
SMS is pursuing additional funding opportunities through SpaceWERX Phase II and Army Sequential Phase II SBIR programs. We welcome partners interested in co-development or field testing. Potential customers or end users can also strengthen our proposals by sharing operational requirements, providing technical feedback, or offering letters of support that demonstrate mission relevance and transition potential. Contact us to learn more or request a free sample!