Morphological, Chemical, and Electronic Changes of the Conjugated Polymer PTB7 with Thermal Annealing

Savikhin, Victoria; Jagadamma, Lethy K.; Purvis, Lafe J.; Robertson, Iain; Oosterhout, Stefan D.; Douglas, Christopher J.; Samuel, Ifor D. W.; Toney, Michael F.

doi:10.1016/j.isci.2018.03.002

Title: Morphological, Chemical, and Electronic Changes of the Conjugated Polymer PTB7 with Thermal Annealing

Journal Article · 22 March 2018 · iScience

DOI: https://doi.org/10.1016/j.isci.2018.03.002 · OSTI ID:1430557

Savikhin, Victoria ^[1]; Jagadamma, Lethy K. ^[2]; Purvis, Lafe J. ^[3]; Robertson, Iain ^[2]; Oosterhout, Stefan D. ^[4]; Douglas, Christopher J. ^[3]; Samuel, Ifor D. W. ^[2];

^[4]

SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); Stanford Univ., CA (United States)
Univ. of St. Andrews, Scotland (United Kingdom)
University of Minnesota – Twin Cities, Minneapolis, MN (United States)
SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)

There is considerable interest in improving the performance of organic optoelectronic devices through processing techniques. Here, we study the effect of high-temperature annealing on the properties of the semiconducting polymer PTB7 and PTB7:fullerene blends, of interest as efficient organic photovoltaic (OPV) devices. Annealing to moderate temperature improves the PTB7 morphology and optoelectronic properties. High-temperature annealing also improves morphology but results in poorer optoelectronic properties. This is a result of side chain cleavage that creates by-products that act as trap states, increasing electronic disorder and decreasing mobility. We further observe changes to the PTB7 chemical structure after thermal cleavage that are similar to those following solar irradiation. This implies that side chain cleavage is an important mechanism in device photodegradation, which is a major "burn-in" loss mechanism in OPV. These results lend insight into side chain cleavage as a method of improving optoelectronic properties and suggest strategies for improvement in device photostability.

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Research Organization:: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES); US Department of the Navy, Office of Naval Research (ONR); Engineering and Physical Sciences Research Council (EPSRC); National Science Foundation (NSF)

Grant/Contract Number:: AC02-76SF00515; N00014-14-1-0580; EP/L017008/1; EP/L012294/1; ECCS-1542152

OSTI ID:: 1430557

Alternate ID(s):: OSTI ID: 1623673

Journal Information:: iScience, Vol. 2, Issue C; ISSN 2589-0042

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 33 works

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