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Advanced Multifunctional Coatings for PV Glass to Reduce Soiling and PID Losses

As a DuraMAT project, WattGlass is conducting a fundamental investigation into the physical and chemical interactions that occur between environmental soils and anti-soiling (AS)/anti-reflective (AR) coatings for photovoltaic (PV) glass. It's using its own AS/AR coating as the pilot material.

The investigation will result in a testing protocol that can be applied to an arbitrary AS/AR coating. It will also facilitate the further development of coatings with novel anti-soiling chemistries.

In addition, WattGlass is evaluating a novel double-sided coating for solar glass to reduce potential induced degradation (PID) losses in high-voltage PV module architectures.

For the project, WattGlass is utilizing advanced X-ray scattering and spectroscopy tools at SLAC National Accelerator Laboratory, as well as the artificial soiling methodologies developed at Sandia National Laboratories (SNL).

Transmittance losses due to soiling of PV modules have a large, negative impact on the levelized cost of electricity. In some geographic regions, the combined effect of soiling losses can result in the reduction of module efficiency and power output in excess of 30%. This has led to much interest in development of AS/AR coatings. However, relatively little is understood about the fundamental mechanisms that contribute to the anti-soiling properties of AS/AR coatings.

Primary Capability Area

Materials Characterization and Forensics


WattGlass, Inc., in collaboration with SLAC and SNL


Knowledge of the physical chemical interactions that occur between AS/AR coatings and environmental soils will:

  • Drive the adoption of AS/AR coatings in the solar industry
  • Help identify geographic regions where specific coating chemistries are optimum
  • Lead to new material designs.


Available to collaborators at national labs and industry.


Moffitt, S.L.; Fleming, R.A.; Thompson, C.S.; Toney, M.F.; Schelhas, L.T. (2018). “Fundamental
Characterization of Anti-Soiling Coatings for PV Glass: Application of Small-Angle X-ray
Scattering.” 2018 IEEE PVSC, Waikoloa, HI, June 10-15.

Fleming, R.A.; Pop, S.C.; Moffitt, S.L.; Schelhas, L.T.; Thompson, C.S. (2018). “Advanced
Multifunctional Coatings for PV Glass to Reduce Soiling and PID Losses.” 2018 NREL
Photovoltaic Reliability Workshop, Golden, CO, February 27 – March 1.

Freiburger, B.; Thompson, C.S.; Fleming, R.A.; Hutchings, D.; Pop, S.C. (2017). “High Efficiency
Anti-Reflective Coating for PV Module Glass.” 2017 IEEE PVSC, Washington, D.C., June 25-30.


To learn more about this project, contact Drew Fleming or Corey Thompson.

Four quadrant image. First quadrant titled” “WattGlass High-Performance Anti-Soiling and Antireflective Coating” with an image that says “Powered by SunShot, U.S. Department of Energy.” Second quadrant titled “Lab-Scale Artificial Soiling Protocols” with images showing bare glass and WattGlass coatings. Third quadrant titled “Advanced X-ray Scattering and Spectroscopy Analysis” with two line charts: one showing Q-vector and the other showing photon energy. Fourth quadrant titled “Understanding Fundamental Interactions to Eliminate PV Module Soiling” with an image of a PV module.