Charge transfer dynamics and interlayer exciton formation in MoS2/VOPc mixed dimensional heterojunction

Madison C. Schwinn, Shahnawaz Rafiq, Changmin Lee, Matthew P. Bland, Thomas W. Song, Vinod K. Sangwan, Mark C. Hersam, Lin X. Chen

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Mixed-dimensional van der Waals heterojunctions involve interfacing materials with different dimensionalities, such as a 2D transition metal dichalcogenide and a 0D organic semiconductor. These heterojunctions have shown unique interfacial properties not found in either individual component. Here, we use femtosecond transient absorption to reveal photoinduced charge transfer and interlayer exciton formation in a mixed-dimensional type-II heterojunction between monolayer MoS2 and vanadyl phthalocyanine (VOPc). Selective excitation of the MoS2 exciton leads to hole transfer from the MoS2 valence band to VOPc highest occupied molecular orbit in ∼710 fs. On the contrary, selective photoexcitation of the VOPc layer leads to instantaneous electron transfer from its excited state to the conduction band of MoS2 in less than 100 fs. This light-initiated ultrafast separation of electrons and holes across the heterojunction interface leads to the formation of an interlayer exciton. These interlayer excitons formed across the interface lead to longer-lived charge-separated states of up to 2.5 ns, longer than in each individual layer of this heterojunction. Thus, the longer charge-separated state along with ultrafast charge transfer times provide promising results for photovoltaic and optoelectronic device applications.

Original languageEnglish
Article number184701
JournalJournal of Chemical Physics
Issue number18
StatePublished - Nov 14 2022

Bibliographical note

Funding Information:
L.X.C. and M.C.S. acknowledge the partial support from CBGS, Basic Energy Science, Office of Science, the U.S. Department of Energy, through the Argonne National Laboratory under Contract No. DE-AC02-06CH11357. S.R. acknowledges his partial support from the U.S. National Science Foundation (Grant No. CHE-1955806 to L.X.C.), and C.L. acknowledges his partial support from the National Institutes of Health (under Contract No. R01-GM115761 to L.X.C.). M.P.B., V.K.S., and M.C.H. acknowledge support from the National Science Foundation Materials Research Science and Engineering Center at Northwestern University (Grant No. NSF DMR-1720139) for CVD growth and characterization of monolayer MoS. T.W.S. and M.C.H. acknowledge support from the National Science Foundation Division of Materials Research (Grant No. NSF DMR-2004420) for VOPc thin-film deposition and characterization. This work made use of the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (Grant No. NSF ECCS-2025633), the IIN, and Northwestern’s MRSEC program (Grant No. NSF DMR-1720139). The authors acknowledge Brendan P. Kerwin for providing sublimed VOPc for quality comparison. 2

Publisher Copyright:
© 2022 Author(s).

ASJC Scopus subject areas

  • Physics and Astronomy (all)
  • Physical and Theoretical Chemistry


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