Title
Imaging 0.36 nm Lattice Planes in Conjugated Polymers by Minimizing Beam Damage
Date Issued
13 October 2020
Access level
open access
Resource Type
journal article
Author(s)
Pennsylvania State University
Publisher(s)
American Chemical Society
Abstract
Transmission electron microscopy can resolve the atomic structure of materials with 0.5 Å resolution. High-resolution transmission electron microscopy (HRTEM) of soft materials, however, is limited by beam damage. We characterized damage in a series of conjugated polymers comprising poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(3-dodecylthiophene-2,5-diyl) (P3DDT), and poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3″'-di(2-octyldodecyl)-2,2′5′,2″5″,2″'-quaterthiophene-5,5″'-diyl)] (PffBT4T-2OD) by monitoring the decay of electron diffraction peaks as a function of dose rate, beam blanking, and temperature. We also measured the decay of low-loss electron energy-loss spectra as a function of dose rate. These damage experiments suggest that the dominant mechanism of beam damage in conjugated polymers is the diffusion of a reacting species generated from ionization, likely of side chains. Elucidating a mechanistic description of radiation effects leads to imaging protocols that can minimize damage, which enables the direct imaging of 3.6 Å π-πstacking in a solution-processed conjugated polymer (PffBT4T-2OD), improving state-of-the-art resolution of this class of materials by an order of magnitude.
Start page
8296
End page
8302
Volume
53
Issue
19
Language
English
OCDE Knowledge area
Ingeniería química Ingeniería de materiales
Scopus EID
2-s2.0-85092065360
Source
Macromolecules
ISSN of the container
00249297
Sponsor(s)
The authors acknowledge financial support from the NSF through Award DMR-1609417 and DMR-1905550. B.K. acknowledges support by the DOE Office of Science Graduate Fellowship program and the Advanced Light Source Doctoral Fellowship in Residence. The work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. The authors thank C. Song for assistance with EELS alignment on the TEAM 0.5.
Sources of information: Directorio de Producción Científica Scopus