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 - Publisher Copyright:
© 2019 American Chemical Society.
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
SN - 1932-7447
VL - 123
SP - 13337
EP - 13343
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 21
ER -