Affordable Access

deepdyve-link
Publisher Website

Disentangling overlapping high-field EPR spectra of organic radicals: Identification of light-induced polarons in the record fullerene-free solar cell blend PBDB-T:ITIC.

Authors
  • Van Landeghem, Melissa1
  • Maes, Wouter2
  • Goovaerts, Etienne3
  • Van Doorslaer, Sabine4
  • 1 Department of Physics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium. Electronic address: [email protected] , (Belgium)
  • 2 Institute for Materials Research, Design & Synthesis of Organic Semiconductors, Hasselt University, Agoralaan 1, 3590 Diepenbeek, Belgium. Electronic address: [email protected] , (Belgium)
  • 3 Department of Physics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium. Electronic address: [email protected] , (Belgium)
  • 4 Department of Physics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium. Electronic address: [email protected] , (Belgium)
Type
Published Article
Journal
Journal of Magnetic Resonance
Publisher
Elsevier
Publication Date
Jan 11, 2018
Volume
288
Pages
1–10
Identifiers
DOI: 10.1016/j.jmr.2018.01.007
PMID: 29367021
Source
Medline
Keywords
License
Unknown

Abstract

We present a combined high-field EPR and DFT study of light-induced radicals in the bulk heterojunction blend of PBDB-T:ITIC, currently one of the highest efficiency non-fullerene donor:acceptor combinations in organic photovoltaics. We demonstrate two different approaches for disentangling the strongly overlapping high-field EPR spectra of the positive and negative polarons after charge separation: (1) relaxation-filtered field-swept EPR based on the difference in T1 spin-relaxation times and (2) field-swept EDNMR-induced EPR by exploiting the presence of 14N hyperfine couplings in only one of the radical species, the small molecule acceptor radical. The approach is validated by light-induced EPR spectra on related blends and the spectral assignment is underpinned by DFT computations. The broader applicability of the spectral disentangling methods is discussed.

Report this publication

Statistics

Seen <100 times