TY - JOUR
T1 - Molecular-Orientation-Dependent Interfacial Charge Transfer in Phthalocyanine/MoS2 Mixed-Dimensional Heterojunctions
AU - Padgaonkar, Suyog
AU - Amsterdam, Samuel H.
AU - Bergeron, Hadallia
AU - Su, Katherine
AU - Marks, Tobin J.
AU - Hersam, Mark C.
AU - Weiss, Emily A.
N1 - Funding Information:
acknowledges support from the Department of Defense through the National Defense Science and Engineering Graduate Fellowship Program. The authors thank Wooje Chang for help with spectroelectrochemical measurements of the CuPc radical cation.
Funding Information:
This research was supported by the Materials Research Science and Engineering Center (MRSEC) of Northwestern University (NSF DMR-1720139) (spectroscopy) and the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0001059 (sample preparation and characterization). This work made use of the Keck-II facility of Northwestern University NU Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. H.B. acknowledges support from the NSERC Postgraduate Scholarshipâ€"Doctoral Program and a National Science Foundation Graduate Research Fellowship. S.H.A. acknowledges support from the Department of Defense through the National Defense Science and Engineering Graduate Fellowship Program.
Funding Information:
This research was supported by the Materials Research Science and Engineering Center (MRSEC) of Northwestern University (NSF DMR-1720139) (spectroscopy) and the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0001059 (sample preparation and characterization). This work made use of the Keck-II facility of Northwestern University NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. H.B. acknowledges support from the NSERC Postgraduate Scholarship−Doctoral Program and a National Science Foundation Graduate Research Fellowship. S.H.A.
PY - 2019/5/30
Y1 - 2019/5/30
N2 - Mixed-dimensional heterojunctions (MDHJs) combine the characteristics of component materials such as the discrete orbital energies of zero-dimensional (0D) molecules and the extended band structure of two-dimensional (2D) semiconductors. Here, time-resolved spectroscopy reveals sub-picosecond photoinduced hole-transfer and sub-320 fs photoinduced electron-transfer processes at the interfaces of type-II copper and free-base phthalocyanine/monolayer MoS2 MDHJs. In CuPc/MoS2 heterojunctions, charge separation lasts as long as 70 ns, which is a factor of 17 longer than that in H2Pc/MoS2 heterojunctions and a factor of 40 longer than that in previously reported transition-metal dichalcogenide-based heterojunctions. Preservation of the charge-separated state is attributed to the face-on orientation of CuPc on the MoS2 surface, which templates stacking of CuPc molecules and facilitates hole migration away from the interface, whereas H2Pc molecules adopt a mixed edge-on and face-on orientation. This work highlights the role of molecular structure in determining the interfacial geometry and, ultimately, charge-transfer dynamics in 0D/2D heterojunctions.
AB - Mixed-dimensional heterojunctions (MDHJs) combine the characteristics of component materials such as the discrete orbital energies of zero-dimensional (0D) molecules and the extended band structure of two-dimensional (2D) semiconductors. Here, time-resolved spectroscopy reveals sub-picosecond photoinduced hole-transfer and sub-320 fs photoinduced electron-transfer processes at the interfaces of type-II copper and free-base phthalocyanine/monolayer MoS2 MDHJs. In CuPc/MoS2 heterojunctions, charge separation lasts as long as 70 ns, which is a factor of 17 longer than that in H2Pc/MoS2 heterojunctions and a factor of 40 longer than that in previously reported transition-metal dichalcogenide-based heterojunctions. Preservation of the charge-separated state is attributed to the face-on orientation of CuPc on the MoS2 surface, which templates stacking of CuPc molecules and facilitates hole migration away from the interface, whereas H2Pc molecules adopt a mixed edge-on and face-on orientation. This work highlights the role of molecular structure in determining the interfacial geometry and, ultimately, charge-transfer dynamics in 0D/2D heterojunctions.
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U2 - 10.1021/acs.jpcc.9b04063
DO - 10.1021/acs.jpcc.9b04063
M3 - Article
AN - SCOPUS:85066729990
VL - 123
SP - 13337
EP - 13343
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 21
ER -