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PVDF-based Backsheet Cracking: Mapping In Situ Phase Evolution by X-ray Scattering
Published
Author(s)
Stephanie Moffitt, Sona Ulicna, Song-Syun Jhang, Po-Chang Pan, Michael Owen-Bellini, Peter Hacke, Michael Kempe, Jared Tracy, Kaushik Choudhury, Laura Schelhas, Xiaohong Gu
Abstract
One of the most common polymers in commercial photovoltaic (PV) backsheets is polyvinylidene fluoride (PVDF). However, recent reports have shown the potential for PVDF-based backsheets to crack and fail prematurely. Previous work has suggested that polymer phase change plays a role in the failure mechanism. Here wide-angle X-ray scattering maps are used to show that α- to β-phase transformations occur at cracks tips in aged PVDF-based backsheets. Substantial β-phase formation is shown to be associated with strain hardening. In addition, our work demonstrates that β-phase formation is not required for crack growth and only occurs at crack tips when plastic deformation of the PVDF polymer has occurred. The anisotropy in the strength of aged PVDF-based backsheets is linked to the lack of β-phase formation when strain is applied to aged backsheets in the transverse direction.
Moffitt, S.
, Ulicna, S.
, Jhang, S.
, Pan, P.
, Owen-Bellini, M.
, Hacke, P.
, Kempe, M.
, Tracy, J.
, Choudhury, K.
, Schelhas, L.
and Gu, X.
(2024),
PVDF-based Backsheet Cracking: Mapping In Situ Phase Evolution by X-ray Scattering, ACS Applied Energy Materials, [online], https://doi.org/10.1016/j.solmat.2024.113355, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956819
(Accessed October 9, 2025)