Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion

Mickey Finn, Christian James Martens, Aliaksandr V. Zaretski, Bérenger Roth, Roar R. Søndergaard, Frederik C Krebs*, Darren J. Lipomi

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The ability of printed organic solar cells (OSCs) to survive repeated mechanical deformation is critical to large-scale implementation. This paper reports an investigation into the mechanical stability of OSCs through bending and torsion testing of whole printed modules. Two types of modules are used that differ slightly in thickness as well as on the basis of the electrode materials: silver nanowires or carbon-based inks. Each type of module is subjected to two different mechanical modes of deformation, bending and torsion, of several thousand cycles per module using a purpose-built robotic device. Analysis of the distribution of stress in the devices performed by finite-element modeling predicts the locations of failure. Failure upon bending originates at the laser-cut edges of the modules from shear at the clamp/module interface leading to crazing of the plastic barrier encapsulant foils. This crazing leads to eventual delamination due first to decohesion of the active layer at the edge of the modules and later to deadhesion between the PEDOT:PSS (electrode) and P3HT:PCBM (semiconductor) layers. The torsion mode imposes greater stresses than the bending mode and thus leads to failure at fewer strain cycles. Failure during torsion occurs through crack propagation initiated at stress concentrations on the edges of the module that were imposed by their rectangular geometry and ultimately leads to bifurcation of the entire module. Rather than the differences in electrode materials, the differences in survivability between the two types of modules are attributed mostly to the thickness of the substrate materials used, with the thinner substrate used in the carbon-based modules (~160 µm) failing at fewer strain cycles than the substrate used in the silver-nanowire-based modules (~190 µm). Taken together, the results suggest ways in which the lifetimes of devices can be extended by the layouts of modules and choices of materials.
Original languageEnglish
JournalSolar Energy Materials and Solar Cells
Volume174
Pages (from-to)7-15
ISSN0927-0248
DOIs
Publication statusPublished - 2018

Keywords

  • Organic solar cell
  • Conjugated polymer
  • Flexible electronics
  • Barrier encapsulation
  • Mechanical stability
  • Cyclic fatigue testing

Cite this

Finn, M., Martens, C. J., Zaretski, A. V., Roth, B., Søndergaard, R. R., Krebs, F. C., & Lipomi, D. J. (2018). Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion. Solar Energy Materials and Solar Cells, 174, 7-15. https://doi.org/10.1016/j.solmat.2017.08.015
Finn, Mickey ; Martens, Christian James ; Zaretski, Aliaksandr V. ; Roth, Bérenger ; Søndergaard, Roar R. ; Krebs, Frederik C ; Lipomi, Darren J. / Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion. In: Solar Energy Materials and Solar Cells. 2018 ; Vol. 174. pp. 7-15.
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title = "Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion",
abstract = "The ability of printed organic solar cells (OSCs) to survive repeated mechanical deformation is critical to large-scale implementation. This paper reports an investigation into the mechanical stability of OSCs through bending and torsion testing of whole printed modules. Two types of modules are used that differ slightly in thickness as well as on the basis of the electrode materials: silver nanowires or carbon-based inks. Each type of module is subjected to two different mechanical modes of deformation, bending and torsion, of several thousand cycles per module using a purpose-built robotic device. Analysis of the distribution of stress in the devices performed by finite-element modeling predicts the locations of failure. Failure upon bending originates at the laser-cut edges of the modules from shear at the clamp/module interface leading to crazing of the plastic barrier encapsulant foils. This crazing leads to eventual delamination due first to decohesion of the active layer at the edge of the modules and later to deadhesion between the PEDOT:PSS (electrode) and P3HT:PCBM (semiconductor) layers. The torsion mode imposes greater stresses than the bending mode and thus leads to failure at fewer strain cycles. Failure during torsion occurs through crack propagation initiated at stress concentrations on the edges of the module that were imposed by their rectangular geometry and ultimately leads to bifurcation of the entire module. Rather than the differences in electrode materials, the differences in survivability between the two types of modules are attributed mostly to the thickness of the substrate materials used, with the thinner substrate used in the carbon-based modules (~160 {\^A}µm) failing at fewer strain cycles than the substrate used in the silver-nanowire-based modules (~190 {\^A}µm). Taken together, the results suggest ways in which the lifetimes of devices can be extended by the layouts of modules and choices of materials.",
keywords = "Organic solar cell, Conjugated polymer, Flexible electronics, Barrier encapsulation, Mechanical stability, Cyclic fatigue testing",
author = "Mickey Finn and Martens, {Christian James} and Zaretski, {Aliaksandr V.} and B{\'e}renger Roth and S{\o}ndergaard, {Roar R.} and Krebs, {Frederik C} and Lipomi, {Darren J.}",
year = "2018",
doi = "10.1016/j.solmat.2017.08.015",
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volume = "174",
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Finn, M, Martens, CJ, Zaretski, AV, Roth, B, Søndergaard, RR, Krebs, FC & Lipomi, DJ 2018, 'Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion', Solar Energy Materials and Solar Cells, vol. 174, pp. 7-15. https://doi.org/10.1016/j.solmat.2017.08.015

Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion. / Finn, Mickey; Martens, Christian James; Zaretski, Aliaksandr V.; Roth, Bérenger; Søndergaard, Roar R.; Krebs, Frederik C; Lipomi, Darren J.

In: Solar Energy Materials and Solar Cells, Vol. 174, 2018, p. 7-15.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion

AU - Finn, Mickey

AU - Martens, Christian James

AU - Zaretski, Aliaksandr V.

AU - Roth, Bérenger

AU - Søndergaard, Roar R.

AU - Krebs, Frederik C

AU - Lipomi, Darren J.

PY - 2018

Y1 - 2018

N2 - The ability of printed organic solar cells (OSCs) to survive repeated mechanical deformation is critical to large-scale implementation. This paper reports an investigation into the mechanical stability of OSCs through bending and torsion testing of whole printed modules. Two types of modules are used that differ slightly in thickness as well as on the basis of the electrode materials: silver nanowires or carbon-based inks. Each type of module is subjected to two different mechanical modes of deformation, bending and torsion, of several thousand cycles per module using a purpose-built robotic device. Analysis of the distribution of stress in the devices performed by finite-element modeling predicts the locations of failure. Failure upon bending originates at the laser-cut edges of the modules from shear at the clamp/module interface leading to crazing of the plastic barrier encapsulant foils. This crazing leads to eventual delamination due first to decohesion of the active layer at the edge of the modules and later to deadhesion between the PEDOT:PSS (electrode) and P3HT:PCBM (semiconductor) layers. The torsion mode imposes greater stresses than the bending mode and thus leads to failure at fewer strain cycles. Failure during torsion occurs through crack propagation initiated at stress concentrations on the edges of the module that were imposed by their rectangular geometry and ultimately leads to bifurcation of the entire module. Rather than the differences in electrode materials, the differences in survivability between the two types of modules are attributed mostly to the thickness of the substrate materials used, with the thinner substrate used in the carbon-based modules (~160 µm) failing at fewer strain cycles than the substrate used in the silver-nanowire-based modules (~190 µm). Taken together, the results suggest ways in which the lifetimes of devices can be extended by the layouts of modules and choices of materials.

AB - The ability of printed organic solar cells (OSCs) to survive repeated mechanical deformation is critical to large-scale implementation. This paper reports an investigation into the mechanical stability of OSCs through bending and torsion testing of whole printed modules. Two types of modules are used that differ slightly in thickness as well as on the basis of the electrode materials: silver nanowires or carbon-based inks. Each type of module is subjected to two different mechanical modes of deformation, bending and torsion, of several thousand cycles per module using a purpose-built robotic device. Analysis of the distribution of stress in the devices performed by finite-element modeling predicts the locations of failure. Failure upon bending originates at the laser-cut edges of the modules from shear at the clamp/module interface leading to crazing of the plastic barrier encapsulant foils. This crazing leads to eventual delamination due first to decohesion of the active layer at the edge of the modules and later to deadhesion between the PEDOT:PSS (electrode) and P3HT:PCBM (semiconductor) layers. The torsion mode imposes greater stresses than the bending mode and thus leads to failure at fewer strain cycles. Failure during torsion occurs through crack propagation initiated at stress concentrations on the edges of the module that were imposed by their rectangular geometry and ultimately leads to bifurcation of the entire module. Rather than the differences in electrode materials, the differences in survivability between the two types of modules are attributed mostly to the thickness of the substrate materials used, with the thinner substrate used in the carbon-based modules (~160 µm) failing at fewer strain cycles than the substrate used in the silver-nanowire-based modules (~190 µm). Taken together, the results suggest ways in which the lifetimes of devices can be extended by the layouts of modules and choices of materials.

KW - Organic solar cell

KW - Conjugated polymer

KW - Flexible electronics

KW - Barrier encapsulation

KW - Mechanical stability

KW - Cyclic fatigue testing

U2 - 10.1016/j.solmat.2017.08.015

DO - 10.1016/j.solmat.2017.08.015

M3 - Journal article

VL - 174

SP - 7

EP - 15

JO - Solar Energy Materials & Solar Cells

JF - Solar Energy Materials & Solar Cells

SN - 0927-0248

ER -