Skip to main content

Cross-Sectional Depth Profiling of Accelerated and Field-Aged Backsheet Materials

DuraMAT is preparing photovoltaic (PV) backsheets, which underwent accelerated and field testing in the DuraMAT BACKFLIP project, for cross-sectional examination to understand the degradation through each backsheet layer and their interfaces.

Characterization methods include Raman spectroscopy and indentation studies.

PV backsheets are the traditional rear-surface material in a PV module, exposed to the outside environment. Backsheets are typically multilayer composites made with different polymer materials that each address properties such as electrical insulation or environmental durability.

Core Objective

Fielded Module Forensics


Sandia National Laboratories and National Renewable Energy Laboratory


This work will provide insight into the reliability of known and emerging backsheet materials and is proposed to increase the understanding of the recent BACKFLIP project by examining the cross-section. If the material degradation can be better understood, this facilitates improved material selection for module designs, lifetime predictions, and rate modeling by degradation mode. Where loss of mechanical integrity or electrical insulation was observed in BACKFLIP, the enabling mechanism is here studied using layer-specific examination.


Data and analysis from this study will be published on the DuraMAT Datahub.


[1] N. Al Hasan et al., “Arrhenius Analysis of the Degradation Modes in BackFLIP Study of Emerging Photovoltaic Backsheets,” Philadelphia, PA, 2022. doi: NREL/CP-5K00-82633.

[2] M. Thuis et al., “A Comparison of Emerging Nonfluoropolymer-Based Coextruded PV Backsheets to Industry-Benchmark Technologies,” IEEE J. Photovolt., vol. 12, no. 1, pp. 88–96, 2022, doi: 10.1109/JPHOTOV.2021.3117915.

[3] K. J. Geretschläger, G. M. Wallner, and J. Fischer, “Structure and basic properties of photovoltaic module backsheet films,” Sol. Energy Mater., vol. 144, pp. 451–456, 2016, doi: 10.1016/j.solmat.2015.09.060.

[4] C.-C. Lin, P. J. Krommenhoek, S. S. Watson, and X. Gu, “Depth profiling of degradation of multilayer photovoltaic backsheets after accelerated laboratory weathering: Cross-sectional Raman imaging,” Sol. Energy Mater., vol. 144, pp. 289–299, 2016, doi: 10.1016/j.solmat.2015.09.021.


To learn more about this project, contact Elizabeth Palmiotti.

A backsheet indicating how Raman spectroscopy and nano indentation are used to assess degradation of each layer, compare accelerated to fielded, and understand BACKFLIP results.