Mapping the Competition between Exciton Dissociation and Charge Transport in Organic Solar Cells

Soong Ju Oh, Jongbok Kim, Jeffrey M. Mativetsky, Yueh Lin Loo, Cherie R. Kagan

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The competition between exciton dissociation and charge transport in organic solar cells comprising poly(3-hexylthiophene) [P3HT] and phenyl-C61-butyric acid methyl ester [PCBM] is investigated by correlated scanning confocal photoluminescence and photocurrent microscopies. Contrary to the general expectation that higher photoluminescence quenching is indicative of higher photocurrent, microscale mapping of bulk-heterojunction solar-cell devices shows that photoluminescence quenching and photocurrent can be inversely proportional to one another. To understand this phenomenon, we construct a model system by selectively laminating a PCBM layer onto a P3HT film to form a PCBM/P3HT planar junction on half of the device and a P3HT single junction on the other half. Upon thermal annealing to allow for interdiffusion of PCBM into P3HT, an inverse relationship between photoluminescence quenching and photocurrent is observed at the boundary between the PCBM/P3HT junction and P3HT layer. Incorporation of PCBM in P3HT works to increase photoluminescence quenching, consistent with efficient charge separation, but conductive atomic force microscopy measurements reveal that PCBM acts to decrease P3HT hole mobility, limiting the efficiency of charge transport. This suggests that photoluminescence-quenching measurements should be used with caution in evaluating new organic materials for organic solar cells.

Original languageEnglish
Pages (from-to)28743-28749
Number of pages7
JournalACS Applied Materials and Interfaces
Volume8
Issue number42
DOIs
Publication statusPublished - 2016 Oct 26

Fingerprint

Butyric acid
Excitons
Butyric Acid
Charge transfer
Esters
Photoluminescence
Quenching
Photocurrents
Laminating
Hole mobility
Organic solar cells
poly(3-hexylthiophene)
LDS 751
Heterojunctions
Atomic force microscopy
Solar cells
Microscopic examination
Annealing
Scanning

Keywords

  • charge transport
  • exciton dissociation
  • organic solar cells
  • scanning confocal photoluminescence microscopy
  • scanning photocurrent microscopy

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Mapping the Competition between Exciton Dissociation and Charge Transport in Organic Solar Cells. / Oh, Soong Ju; Kim, Jongbok; Mativetsky, Jeffrey M.; Loo, Yueh Lin; Kagan, Cherie R.

In: ACS Applied Materials and Interfaces, Vol. 8, No. 42, 26.10.2016, p. 28743-28749.

Research output: Contribution to journalArticle

Oh, Soong Ju ; Kim, Jongbok ; Mativetsky, Jeffrey M. ; Loo, Yueh Lin ; Kagan, Cherie R. / Mapping the Competition between Exciton Dissociation and Charge Transport in Organic Solar Cells. In: ACS Applied Materials and Interfaces. 2016 ; Vol. 8, No. 42. pp. 28743-28749.
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