Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.
We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy.
Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg, Sweden. Electronic address: obacke@chalmers.se.
Olof
O
Bäcke
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Camilla
C
Lindqvist
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Amaia Diaz
AD
de Zerio Mendaza
Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg, Sweden.
Stefan
S
Gustafsson
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Ergang
E
Wang
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Mats R
MR
Andersson
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Christian
C
Müller
Institute of Polymer Nanotechnology (INKA), FHNW University of Applied Science and Arts Northwestern Switzerland, 5210 Windisch, Switzerland; Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Per Magnus
PM
Kristiansen
Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg, Sweden. Electronic address: eva.olsson@chalmers.se.
Eva
E
Olsson
Crosslinking; Electron irradiation; In-situ transmission electron microscopy; Organic solar cells; Thermal stability