A Spatially-Resolved Evaluation of Accelerated Environmental Aging on Emerging Polypropylene-based Photovoltaic Backsheets using Raman Spectroscopy

Published

March 13, 2025

Author(s)

Ashlee Aiello, Stefan Mitterhofer, Jan Obrzut, Karissa Jensen, Patryk Wasik, Chiara Barretta, Gernot Oreski, Stephanie Watson, Li Piin Sung, Xiaohong Gu

Abstract

Accelerated aging was used to assess environmental degradation in emerging co-extruded polypropylene (PP)-based backsheets under three different environmental conditions (65 °C/20 % relative humidity (RH), 75 °C/20 % RH, and 75 °C/50 % RH). Although differential scanning calorimetry did not measure crystallinity changes with exposure, spatially-resolved Raman spectroscopy identified crystallinity increases in the core layer of aged samples, indicating a heterogeneous post-crystallinity process. These results were in agreement synchrotron-based microfocused wide-angle X-ray scattering measurements. Nanoindentation was used to correlate localized crystallinity shifts with changes in Young's modulus. A similar trend was found where increased modulus was measured in the core layer, supporting the relationship between modulus and crystallinity. Finally, dielectric characterization was used to assess the impact of these material property changes on performance. While changes in the backsheet material properties and dielectric performance were observed with accelerated aging, these shifts generally equilibrated with time, indicating general overall stability in response to environmental stressors. Additionally, the heterogeneous material property shifts identified indicate that spatially-resolved crystallinity measurements may be a valuable early failure indicator to be used in the assessment of PV backsheet reliability.

Citation

Progress in Photovoltaics

Pub Type

Journals

Download Paper

https://doi.org/10.1002/pip.3904

Local Download

Keywords

Raman spectroscopy, accelerated aging, backsheets, nanoindentation, photovoltaics (PVs), polypropylene, polyolefin

Citation

Aiello, A. , Mitterhofer, S. , Obrzut, J. , Jensen, K. , Wasik, P. , Barretta, C. , Oreski, G. , Watson, S. , Sung, L. and Gu, X. (2025), A Spatially-Resolved Evaluation of Accelerated Environmental Aging on Emerging Polypropylene-based Photovoltaic Backsheets using Raman Spectroscopy, Progress in Photovoltaics, [online], https://doi.org/10.1002/pip.3904, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958613 (Accessed March 31, 2025)