Interplay between Charge Carrier Mobility, Exciton Diffusion, Crystal Packing, and Charge Separation in Perylene Diimide-Based Heterojunctions

Kevin M. Felter, Valentina M. Caselli, D. Deniz Günbaş, Tom J. Savenije, Ferdinand C. Grozema

Research output: Contribution to journalArticleScientificpeer-review

7 Citations (Scopus)
40 Downloads (Pure)

Abstract

Two of the key parameters that characterize the usefulness of organic semiconductors for organic or hybrid organic/inorganic solar cells are the mobility of charges and the diffusion length of excitons. Both parameters are strongly related to the supramolecular organization in the material. In this work we have investigated the relation between the solid-state molecular packing and the exciton diffusion length, charge carrier mobility, and charge carrier separation yield using two perylene diimide (PDI) derivatives which differ in their substitution. We have used the time-resolved microwave photoconductivity technique and measured charge carrier mobilities of 0.32 and 0.02 cm2/(Vs) and determined exciton diffusion lengths of 60 and 18 nm for octyl- and bulky hexylheptyl-imide substituted PDIs, respectively. This diffusion length is independent of substrate type and aggregate domain size. The differences in charge carrier mobility and exciton diffusion length clearly reflect the effect of solid-state packing of PDIs on their optoelectronic properties and show that significant improvements can be obtained by effectively controlling the solid-state packing.

Original languageEnglish
Pages (from-to)8010-8021
Number of pages12
JournalACS Applied Energy Materials
Volume2
Issue number11
DOIs
Publication statusPublished - 2019

Keywords

  • charge separation
  • crystal packing
  • exciton diffusion length
  • microwave conductivity
  • PDI

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