Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Microstructure changes during failure of PVDF-based photovoltaic backsheets



Stephanie Moffitt, Po-Chang Pan, Lakesha Perry, Michael Kempe, Jared Tracy, Kaushik Choudhury, Xiaohong Gu


The backsheet layer of a solar module provides a safety and environmental barrier to the high voltages running through the photovoltaic (PV) cells and electrical contacts within the core of the module. However, in the past decade, backsheet cracking has become one of the most observed failure modes in PV module field surveys. In this work, the degradation of polyvinylidene fluoride (PVDF)-based backsheets is explored. Backsheet samples are either exposed to accelerated laboratory aging (UV light, heat, and moisture) or collected from the field. Fourier transform infrared and Raman spectroscopy, fragmentation testing, atomic force and scanning electron microscopy, and small-angle neutron scattering are combined to develop an understanding of how chemistry and microstructure evolve during aging. Chemical degradation, surface pitting, polymer phase changes, and anisotropic polymer domains are all observed in aged backsheet samples. The results provide insight into the degradation mechanisms that lead to cracking and field failure of PVDF-based backsheets. The comparison of aged PVDF-based backsheets helps to lay the groundwork for limiting polymer-based failure modes in PV modules.
Progress in Photovoltaics


backsheets, accelerated aging, phase-change, polymer degradation


Moffitt, S. , Pan, P. , Perry, L. , Kempe, M. , Tracy, J. , Choudhury, K. and Gu, X. (2022), Microstructure changes during failure of PVDF-based photovoltaic backsheets, Progress in Photovoltaics, [online],, (Accessed June 22, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 21, 2022, Updated November 29, 2022