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Efficient charge generation from triplet excitons in metal-organic heterojunctions

Roth, Friedrich ; Neppl, Stefan ; Shavorskiy, Andrey LU ; Arion, Tiberiu ; Mahl, Johannes ; Seo, Hyun Ook ; Bluhm, Hendrik ; Hussain, Zahid ; Gessner, Oliver and Eberhardt, Wolfgang (2019) In Physical Review B 99(2).
Abstract

The success of many emerging molecular electronics concepts hinges on an atomistic understanding of the underlying electronic dynamics. We employ picosecond time-resolved x-ray photoemission spectroscopy (tr-XPS) to elucidate the roles of singlet and triplet excitons for photoinduced charge generation at a copper-phthalocyanine-C60 heterojunction. Contrary to common belief, fast intersystem crossing to triplet excitons after photoexcitation is not a loss channel but contributes to a significantly larger extent to the time-integrated interfacial charge generation than the initially excited singlet excitons. The tr-XPS data provide direct access to the diffusivity of the triplet excitons DCuPc=(1.8±1.2)×10-5cm2/s (where CuPc is... (More)

The success of many emerging molecular electronics concepts hinges on an atomistic understanding of the underlying electronic dynamics. We employ picosecond time-resolved x-ray photoemission spectroscopy (tr-XPS) to elucidate the roles of singlet and triplet excitons for photoinduced charge generation at a copper-phthalocyanine-C60 heterojunction. Contrary to common belief, fast intersystem crossing to triplet excitons after photoexcitation is not a loss channel but contributes to a significantly larger extent to the time-integrated interfacial charge generation than the initially excited singlet excitons. The tr-XPS data provide direct access to the diffusivity of the triplet excitons DCuPc=(1.8±1.2)×10-5cm2/s (where CuPc is copper-phthalocyanine) and their diffusion length Ldiff=(8±3)nm.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
99
issue
2
article number
020303
publisher
American Physical Society
external identifiers
  • scopus:85059898315
ISSN
2469-9950
DOI
10.1103/PhysRevB.99.020303
language
English
LU publication?
yes
id
016e1b75-5ce0-4bc8-9448-c64883e51add
date added to LUP
2022-04-04 09:55:05
date last changed
2023-11-24 06:44:25
@article{016e1b75-5ce0-4bc8-9448-c64883e51add,
  abstract     = {{<p>The success of many emerging molecular electronics concepts hinges on an atomistic understanding of the underlying electronic dynamics. We employ picosecond time-resolved x-ray photoemission spectroscopy (tr-XPS) to elucidate the roles of singlet and triplet excitons for photoinduced charge generation at a copper-phthalocyanine-C60 heterojunction. Contrary to common belief, fast intersystem crossing to triplet excitons after photoexcitation is not a loss channel but contributes to a significantly larger extent to the time-integrated interfacial charge generation than the initially excited singlet excitons. The tr-XPS data provide direct access to the diffusivity of the triplet excitons DCuPc=(1.8±1.2)×10-5cm2/s (where CuPc is copper-phthalocyanine) and their diffusion length Ldiff=(8±3)nm.</p>}},
  author       = {{Roth, Friedrich and Neppl, Stefan and Shavorskiy, Andrey and Arion, Tiberiu and Mahl, Johannes and Seo, Hyun Ook and Bluhm, Hendrik and Hussain, Zahid and Gessner, Oliver and Eberhardt, Wolfgang}},
  issn         = {{2469-9950}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review B}},
  title        = {{Efficient charge generation from triplet excitons in metal-organic heterojunctions}},
  url          = {{http://dx.doi.org/10.1103/PhysRevB.99.020303}},
  doi          = {{10.1103/PhysRevB.99.020303}},
  volume       = {{99}},
  year         = {{2019}},
}