Efficient charge generation from triplet excitons in metal-organic heterojunctions

Friedrich Roth, Stefan Neppl, Andrey Shavorskiy, Tiberiu Arion, Johannes Mahl, Hyun Ook Seo, Hendrik Bluhm, Zahid Hussain, Oliver Gessner, Wolfgang Eberhardt

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Article number020303
JournalPhysical Review B
Issue number2
Publication statusPublished - 2019 Jan

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics


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