10.1021/acs.jpcc.7b00970.s001
Chao Lu
Chao
Lu
Mamoru Fujitsuka
Mamoru
Fujitsuka
Akira Sugimoto
Akira
Sugimoto
Tetsuro Majima
Tetsuro
Majima
Dual Character of Excited Radical Anions in Aromatic Diimide Bis(radical
anion)s: Donor or Acceptor?
American Chemical Society
2017
Intramolecular electron transfer
photocarrier migration
electron donor
electron acceptor
ET rate constants
substitution positions
Marcus theory
n-type semiconductor materials
PDI
ADI
NDI
disproportionation reactions
Excited Radical Anions
bipolaron-generating nature
Dual Character
femtosecond laser flash photolysis
2017-02-07 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Dual_Character_of_Excited_Radical_Anions_in_Aromatic_Diimide_Bis_radical_anion_s_Donor_or_Acceptor_/4654573
Intramolecular electron
transfer (ET) processes in the excited aromatic diimide bis(radical
anion)s (ADI<sup>•–</sup>*–ADI′<sup>•–</sup>) were systematically investigated by applying femtosecond laser
flash photolysis to bis(radical anion)s of naphthalenediimide (NDI)
and perylenediimide (PDI), including NDI<sup>•–</sup>–<i>m</i>-NDI<sup>•–</sup>, NDI<sup>•–</sup>–<i>p</i>-NDI<sup>•–</sup>, PDI<sup>•–</sup>–<i>m</i>-PDI<sup>•–</sup>, and NDI<sup>•–</sup>–<i>m</i>-PDI<sup>•–</sup> (<i>m</i> and <i>p</i> indicate the substitution positions). The excitation of
NDI<sup>•–</sup>–<i>m</i>-NDI<sup>•–</sup> and NDI<sup>•–</sup>–<i>p</i>-NDI<sup>•–</sup> initiated disproportionation reactions generating
NDI and NDI<sup>2–</sup> with different ET rate constants.
For the first time, the dual characteristics of ADI<sup>•–</sup>* were confirmed upon selective excitation of NDI<sup>•–</sup>–<i>m</i>-PDI<sup>•–</sup>: NDI<sup>•–</sup>* was unambiguously demonstrated to function
as an electron donor in NDI<sup>•–</sup>*–<i>m</i>-PDI<sup>•–</sup>, whereas PDI<sup>•–</sup>* acted as an electron acceptor in NDI<sup>•–</sup>–<i>m</i>-PDI<sup>•–</sup>* because
of the energetically preferable production of NDI–<i>m</i>-PDI<sup>2–</sup>. The relationship between the ET rate constants
and driving forces in ADI<sup>•–</sup>*–ADI′<sup>•–</sup> can be reasonably analyzed by using the Marcus
theory. The current findings provide a new viewpoint regarding the
bipolaron-generating nature of ADI<sup>•–</sup>*–ADI′<sup>•–</sup> and facilitate simulating various types of
photocarrier migration in the densely charged regions of homo- and
heterogeneous n-type semiconductor materials upon irradiation.