Charge generation in polymer: perylene diimide blends probed by Vis-NIR broadband transient absorption pump-probe spectroscopy

D. Gehrig, I. A. Howard, V. Kamm, C. Dyer-Smith, F. Etzold, F. Laquai

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

We report the photovoltaic performance of a low-bandgap polymer:perylene diimide (PDI) photovoltaic blend and study the exciton to charge carrier conversion in the photoactive layer by Vis-NIR broadband transient absorption spectroscopy over a dynamic range from pico- to microseconds. Power conversion efficiencies of 1.2 % are obtained from the polymer:PDI blends with a maximum EQE of about 30 %, which is significantly below the performance of the same polymer with fullerene as acceptor indicating that severe loss processes exist that limit the photocurrent. From the evolution of the transient absorption spectra we conclude that the photovoltaic performance of the polymer:PDI blends is mainly limited by inefficient exciton harvesting and dissociation at the interface. However, once free charge carriers are generated in the blend they can be extracted as photocurrent as their recombination occurs on a timescale similar to the time typically needed for charge extraction from the photoactive layer. Hence, strategies to improve the efficiency of polymer:PDI blends should aim at increasing exciton harvesting at the heterojunction and the dissociation efficiency into free charges at the interface.

Original languageEnglish (US)
Title of host publicationPhysical Chemistry of Interfaces and Nanomaterials XII
Volume8811
DOIs
StatePublished - 2013
Externally publishedYes
EventPhysical Chemistry of Interfaces and Nanomaterials XII - San Diego, CA, United States
Duration: Aug 25 2013Aug 28 2013

Other

OtherPhysical Chemistry of Interfaces and Nanomaterials XII
CountryUnited States
CitySan Diego, CA
Period08/25/1308/28/13

Keywords

  • Charge carrier dynamics
  • Low-bandgap polymer
  • Non-fullerene acceptors
  • Organic photovoltaics
  • Perylene diimide
  • Transient absorption spectroscopy

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Charge generation in polymer: perylene diimide blends probed by Vis-NIR broadband transient absorption pump-probe spectroscopy'. Together they form a unique fingerprint.

Cite this