Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study
Journal article, 2015

The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk-heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk-heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals, ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components.

Author

Olof Bäcke

Chalmers, Applied Physics, Eva Olsson Group

Camilla Lindqvist

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Amaia Diaz de Zerio Mendaza

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Stefan Gustafsson

SuMo Biomaterials

Chalmers, Applied Physics, Eva Olsson Group

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Mats Andersson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Christian Müller

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Eva Olsson

Chalmers, Applied Physics, Eva Olsson Group

Nanoscale

2040-3364 (ISSN)

Vol. 7 18 8451-8456

Enabling Science and Technology through European Electron Microscopy (ESTEEM 2)

European Commission (FP7), 2012-10-01 -- 2016-09-30.

Subject Categories

Polymer Chemistry

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Energy

Materials Science

DOI

10.1039/c5nr00443h

More information

Created

10/7/2017