Long-Lived, Non-Geminate, Radiative Recombination of Photogenerated Charges in a Polymer/Small-Molecule Acceptor Photovoltaic Blend

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

12 Scopus Citations
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Author(s)

  • Mark E. Ziffer
  • Sae Byeok Jo
  • Hongliang Zhong
  • Long Ye
  • Hongbin Liu
  • Francis Lin
  • Jie Zhang
  • Xiaosong Li
  • Harald W. Ade
  • David S. Ginger

Detail(s)

Original languageEnglish
Pages (from-to)9996-10008
Journal / PublicationJournal of the American Chemical Society
Volume140
Issue number31
Early online date14 Jul 2018
Publication statusPublished - 8 Aug 2018

Abstract

Minimization of open-circuit-voltage (VOC) loss is required to transcend the efficiency limitations on the performance of organic photovoltaics (OPV). We study charge recombination in an OPV blend comprising a polymer donor with a small molecule nonfullerene acceptor that exhibits both high photovoltaic internal quantum efficiency and relatively high external electroluminescence quantum efficiency. Notably, this donor/acceptor blend, consisting of the donor polymer commonly referred to as PCE10 with a pseudoplanar small molecule acceptor (referred to as FIDTT-2PDI) exhibits relatively bright delayed photoluminescence on the microsecond time scale beyond that observed in the neat material. We study the photoluminescence decay kinetics of the blend in detail and conclude that this long-lived photoluminescence arises from radiative nongeminate recombination of charge carriers, which we propose occurs via a donor/acceptor CT state located close in energy to the singlet state of the polymer donor. Additionally, crystallographic and spectroscopic studies point toward low subgap disorder, which could be beneficial for low radiative and nonradiative losses. These results provide an important demonstration of photoluminescence due to nongeminate charge recombination in an efficient OPV blend, a key step in identifying new OPV materials and materials-screening criteria if OPV is to approach the theoretical limits to efficiency.

Research Area(s)

Citation Format(s)

Long-Lived, Non-Geminate, Radiative Recombination of Photogenerated Charges in a Polymer/Small-Molecule Acceptor Photovoltaic Blend. / Ziffer, Mark E.; Jo, Sae Byeok; Zhong, Hongliang; Ye, Long; Liu, Hongbin; Lin, Francis; Zhang, Jie; Li, Xiaosong; Ade, Harald W.; Jen, Alex K.-Y.; Ginger, David S.

In: Journal of the American Chemical Society, Vol. 140, No. 31, 08.08.2018, p. 9996-10008.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review