TY - JOUR
T1 - Effect of the Electron Transport Layer on the Interfacial Energy Barriers and Lifetime of R2R Printed Organic Solar Cell Modules
AU - Vilkman, Marja
AU - Väisänen, Kaisa-Leena
AU - Apilo, Pälvi
AU - Po, Riccardo
AU - Välimäki, Marja
AU - Ylikunnari, Mari
AU - Bernardi, Andrea
AU - Pernu, Tapio
AU - Corso, Gianni
AU - Seitsonen, Jani
AU - Heinilehto, Santtu
AU - Ruokolainen, Janne
AU - Hast, Jukka
N1 - Funding Information:
The authors acknowledge financial support from Eni S.p.A and VTT Technical Research Centre of Finland LtD. Anne Peltoniemi is acknowledged for assisting in the characterization of the modules, Mikko Hietala for operating the R2R machine, and Pentti Korhonen for drawing the layouts and ordering the printing cylinders and screens.
Publisher Copyright:
© Copyright 2018 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2018/11/26
Y1 - 2018/11/26
N2 - Understanding the phenomena at interfaces is crucial for producing efficient and stable flexible organic solar cell modules. Minimized energy barriers enable efficient charge transfer and good adhesion allows mechanical and environmental stability, and thus increased lifetime. We utilize here the inverted organic solar module stack and standard photoactive materials (a blend of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester) to study the interfaces in a pilot scale large-area roll-to-roll (R2R) process. The results show that the adhesion and work function of the zinc oxide nanoparticle based electron transport layer can be controlled in the R2R process, which allows optimization of performance and lifetime. Plasma treatment of zinc oxide (ZnO) nanoparticles and encapsulation-induced oxygen trapping will increase the absolute value of the ZnO work function, resulting in energy barriers and an S-shaped IV curve. However, light soaking will decrease the zinc oxide work function close to the original value and the S-shape can be recovered, leading to power conversion efficiencies above 3 %. We present also an electrical simulation, which supports the results. Finally, we study the effect of plasma treatment in more detail and show that we can effectively remove the organic ligands around the ZnO nanoparticles from the printed layer in a R2R process, resulting in increased adhesion. This post-printing plasma treatment increases the lifetime of the R2R printed modules significantly with modules retaining 80% of their efficiency for ca. 3000 hours in accelerated conditions. Without plasma treatment, this efficiency level is reached in less than 1000 hours.
AB - Understanding the phenomena at interfaces is crucial for producing efficient and stable flexible organic solar cell modules. Minimized energy barriers enable efficient charge transfer and good adhesion allows mechanical and environmental stability, and thus increased lifetime. We utilize here the inverted organic solar module stack and standard photoactive materials (a blend of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester) to study the interfaces in a pilot scale large-area roll-to-roll (R2R) process. The results show that the adhesion and work function of the zinc oxide nanoparticle based electron transport layer can be controlled in the R2R process, which allows optimization of performance and lifetime. Plasma treatment of zinc oxide (ZnO) nanoparticles and encapsulation-induced oxygen trapping will increase the absolute value of the ZnO work function, resulting in energy barriers and an S-shaped IV curve. However, light soaking will decrease the zinc oxide work function close to the original value and the S-shape can be recovered, leading to power conversion efficiencies above 3 %. We present also an electrical simulation, which supports the results. Finally, we study the effect of plasma treatment in more detail and show that we can effectively remove the organic ligands around the ZnO nanoparticles from the printed layer in a R2R process, resulting in increased adhesion. This post-printing plasma treatment increases the lifetime of the R2R printed modules significantly with modules retaining 80% of their efficiency for ca. 3000 hours in accelerated conditions. Without plasma treatment, this efficiency level is reached in less than 1000 hours.
KW - organic solar cell modules
KW - R2R printing
KW - lifetime
KW - adhesion
KW - energy barrier
KW - zinc oxide
UR - http://www.scopus.com/inward/record.url?scp=85064841112&partnerID=8YFLogxK
U2 - 10.1021/acsaem.8b01040
DO - 10.1021/acsaem.8b01040
M3 - Article
C2 - 30506039
SN - 2574-0962
VL - 1
SP - 5977
EP - 5985
JO - ACS Applied Energy Materials
JF - ACS Applied Energy Materials
IS - 11
ER -