UV-curable self-healing polymer layers for increased sustainability of photovoltaics

Dorothee Ehrhardt, Kurt Van Durme, Johan Jansen, Bruno Van Mele, Niko Van den Brande

Research output: Unpublished contribution to conferenceUnpublished abstract

Abstract

Typically, photovoltaic manufacturers guarantee a module lifespan of 25 years, during which photovoltaic modules must
withstand the effects of outside conditions with limited performance reduction. However, daily thermal cycling and fast
temperature changes cause thermal stresses between contiguous materials (due to mismatching thermal expansion
coefficients), which lead to the formation of small fractures and cracks. By replacing conventional polymer layers used in
photovoltaics by self-healing polymer materials, such micro-defects can be repaired before they increase in size and turn
into larger defects, which may affect the energy output. Consequently, the sustainability of photovoltaics is increased.
In this work, UV-crosslinked polymer networks containing reversible Diels-Alder bonds were developed to function as
autonomously self-healing materials. It is shown by means of Fourier transform infrared spectroscopy, (modulated
temperature) differential scanning calorimetry and dynamic mechanical analysis that these polymer networks have the
potential to exploit the daily temperature cycle to achieve self-healing through thermally reversible chemical crosslinking,
and that they maintain structural integrity over the whole photovoltaics application temperature range (-40 to 85 °C).
Recently, room-temperature healing of a fully reversible Diels-Alder system based on furan and maleimide was reported,
proving that elevated temperatures are not always required for self-healing. [1] Additionally, it was recently shown on a
similar system that the Diels-Alder reaction continues in diffusion-controlled conditions (below the glass transition
temperature). [2] This means that even if the photovoltaic modules are exposed to moderate or cold outside temperatures
during longer periods, the healing process within the self-healing polymer layers continues.
[1] M. M. Diaz et al., Polymer, vol. 153, pp. 453–463, 2018.
[2] D. Ehrhardt et al., Central and Eastern European Committee for Thermal Analysis and Calorimetry (CEEC-TAC), p.
368 PS2.002, ISBN 978-3-940237-50-7.
Original languageEnglish
PagesPolymer8, ID103
Number of pages1
Publication statusPublished - 3 Jun 2019
Event7th International Conference on Self-Healing Materials (ICSHM2019) - Yokohama, Japan
Duration: 3 Jun 20195 Jun 2019

Conference

Conference7th International Conference on Self-Healing Materials (ICSHM2019)
CountryJapan
CityYokohama
Period3/06/195/06/19

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