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Modeling the Exposure of Photovoltaic Components on the Module

This DuraMAT project consists of a computational effort using raytracing to describe the backside ultraviolet (UV) exposure and environmental chamber measurements to validate parameters for degradation extrapolation looking at multiple modes and degradation steps potentially leading to photovoltaic (PV) material failure.

We will acquire several contemporary backsheet materials of known good and known bad quality and expose them to various conditions of heat, UV, and relative-humidity conditions. Because we need to know the spectral dependence of degradation on UV light, we will use band-pass filters in front of the samples to vary the stress. For the material testing, we will look at loss of elongation to break, loss of adhesion, reduction in tensile strength, color change, and loss of transmittance or reflectance.

The project’s end-product will include both software as open access Python code on PVdeg on GitHub and some typical values for degradation parameters useful to the PV industry.

Core Objective

Multi-Scale, Multi-Physics Model


National Renewable Energy Laboratory (NREL)


This work will be useful for anyone looking to investigate the degradation of backsheets. This will be used to generate realistic exposure and form a basis for comparing chamber studies to the outdoors. This is useful for backsheet manufacturers and for researchers working on the implementation/development of qualification testing.


The results of the experiment will be published in peer reviewed journals and the Python code will be publicly available on PVdeg on GitHub.


[1] T. C. R. Russell, R. Saive, A. Augusto, S. G. Bowden, and H. A. Atwater, "The Influence of Spectral Albedo on Bifacial Solar Cells: A Theoretical and Experimental Study," IEEE Journal of Photovoltaics, vol. 7, no. 6, pp. 1611-1618, 2017, doi: 10.1109/JPHOTOV.2017.2756068.

[2] X. Gu et al., "Linking Accelerated Laboratory Test with Outdoor Performance Results for a Model Epoxy Coating System," in Service Life Prediction of Polymeric Materials, Boston, MA, J. W. Martin, R. A. Ryntz, J. Chin, and R. A. Dickie, Eds., 2009// 2009: Springer US, pp. 3-28.

[3]  M. Brown, S. Ovaitt, C. Deline, and M. D. Kempe, "Spectral Rear Irradiance Testing and Modeling for Degradation and Performance of Solar Fields: Preprint," presented at the Conference: Presented at the 49th IEEE Photovoltaic Specialists Conference (PVSC 49), 5-10 June 2022, Philadelphia, Pennsylvania, United States, 2022. [Online]. Available:


To learn more about this project, contact Michael Kempe, Silvana Ovaitt, and Martin Springer.


To show exposure, arrows from the sun, a cloud, and the earth pointing at two PV modules.