TY - JOUR
T1 - Decoupling Chemically Active 2D Molecular Overlayers from the Substrate
T2 - Chlorophenyl Porphyrins on Graphene/Ir(111)
AU - Mowbray, Duncan John
AU - Paz, Alejandro Pérez
AU - Ferreira, Rodrigo C.C.
AU - Milotti, Valeria
AU - Schio, Pedro
AU - Simoes e Silva, Wendell
AU - Pichler, Thomas
AU - de Siervo, Abner
AU - Moreno-López, Juan Carlos
N1 - Funding Information:
J.C.M.L. thanks Prof. Byung-Chul Han for sharing his ideas about self-exploitation laborers, which, unfortunately, are disturbingly true in Academia. The authors thank the Brazilian Synchrotron Light Laboratory (LNLS) and the support of the PGM Beamline scientists to our proposal number PGM-20170630. For calculations we have employed the Imbabura cluster of Yachay Tech University, which was purchased under Contract 2017-024 (SIE-UITEY-007-2017). A.P.P. thanks UAEU for an internal start-up grant (No. 31S410). This work has financial support from Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) under Projects 2007/08244-5, 2007/54829-5, and 2017/18574-4 and from Conselho Nacional Científico e Tecnológico (CNPq) from Brazil..
Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.
PY - 2023/5/11
Y1 - 2023/5/11
N2 - The synthesis of atomically precise chemically active 2D molecular overlayers may be hindered by chemical interactions with the underlying substrate, especially when based on chlorophenyl porphyrins. At the same time, the chlorination of graphene, i.e., the covalent bonding of chlorine atoms with sp2 carbon atoms, is known to have a significant influence on the electronic properties of pristine graphene. In this study, we deposit a chlorinated porphyrin molecule, namely 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (Cl4TPP), on graphene/Ir(111). Employing a combined experimental and theoretical approach, we demonstrate that the porphyrin layer physisorbed on graphene self-assembles into a periodic square-like arrangement. This carpet-like growth is unperturbed by the step edges of the substrate, neither in its periodicity nor in its orientation. In addition, the molecular overlayer is thermally stable and does not alter the electronic properties of graphene. Remarkably, we show that Cl4TPP does not experience a dechlorination reaction with the underlying substrate, even after postdeposition annealing temperatures as high as 550 K. Moreover, postdeposition annealing at 700 K suggests the Cl4TPP molecules desorb intact without affecting graphene’s electronic properties. In so doing, we demonstrate the effectiveness of graphene physisorbed on Ir(111) to both promote the formation and preserve the properties of chemically reactive 2D overlayers based on chlorophenyl porphyrins. These results show physisorbed graphene’s potential as a general templating material for the formation of highly reactive self-assembled 2D overlayers.
AB - The synthesis of atomically precise chemically active 2D molecular overlayers may be hindered by chemical interactions with the underlying substrate, especially when based on chlorophenyl porphyrins. At the same time, the chlorination of graphene, i.e., the covalent bonding of chlorine atoms with sp2 carbon atoms, is known to have a significant influence on the electronic properties of pristine graphene. In this study, we deposit a chlorinated porphyrin molecule, namely 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (Cl4TPP), on graphene/Ir(111). Employing a combined experimental and theoretical approach, we demonstrate that the porphyrin layer physisorbed on graphene self-assembles into a periodic square-like arrangement. This carpet-like growth is unperturbed by the step edges of the substrate, neither in its periodicity nor in its orientation. In addition, the molecular overlayer is thermally stable and does not alter the electronic properties of graphene. Remarkably, we show that Cl4TPP does not experience a dechlorination reaction with the underlying substrate, even after postdeposition annealing temperatures as high as 550 K. Moreover, postdeposition annealing at 700 K suggests the Cl4TPP molecules desorb intact without affecting graphene’s electronic properties. In so doing, we demonstrate the effectiveness of graphene physisorbed on Ir(111) to both promote the formation and preserve the properties of chemically reactive 2D overlayers based on chlorophenyl porphyrins. These results show physisorbed graphene’s potential as a general templating material for the formation of highly reactive self-assembled 2D overlayers.
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U2 - 10.1021/acs.jpcc.3c00235
DO - 10.1021/acs.jpcc.3c00235
M3 - Article
AN - SCOPUS:85156275533
SN - 1932-7447
VL - 127
SP - 8751
EP - 8758
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 18
ER -