TY - JOUR
T1 - Empirical Parameter to Compare Molecule-Electrode Interfaces in Large-Area Molecular Junctions
AU - Carlotti, Marco
AU - Soni, Saurabh
AU - Kovalchuk, Andrii
AU - Kumar, Sumit
AU - Hofmann, Stephan
AU - Chiechi, Ryan C.
N1 - Funding Information:
R.C.C., M.C., and A.K. acknowledge the European Research Council for the ERC Starting Grant 335473 (MOLECSYNCON). S.S. acknowledges the Zernike Institute for Advanced Materials. We thank the Center for Information Technology of the University of Groningen for their support and for providing access to the Peregrine high performance computing cluster. M.C. gratefully acknowledges partial support from the European Unions Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement 885881 (MP3). S.K. and S.H. acknowledge funding from EPSRC (EP/T001038/1). We thank Prof. Hyo Jae Yoon, Prof. Michael Zharnikov, and Prof. Christian Nijhuis and their group members for useful discussions and sharing their data.
Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
PY - 2022/5/25
Y1 - 2022/5/25
N2 - This paper describes a simple model for comparing the degree of electronic coupling between molecules and electrodes across different large-area molecular junctions. The resulting coupling parameter can be obtained directly from current-voltage data or extracted from published data without fitting. We demonstrate the generalizability of this model by comparing over 40 different junctions comprising different molecules and measured by different laboratories. The results agree with existing models, reflect differences in mechanisms of charge transport and rectification, and are predictive in cases where experimental limitations preclude more sophisticated modeling. We also synthesized a series of conjugated molecular wires, in which embedded dipoles are varied systematically and at both molecule-electrode interfaces. The resulting current-voltage characteristics vary in nonintuitive ways that are not captured by existing models, but which produce trends using our simple model, providing insights that are otherwise difficult or impossible to explain. The utility of our model is its demonstrative generalizability, which is why simple observables like tunneling decay coefficients remain so widely used in molecular electronics despite the existence of much more sophisticated models. Our model is complementary, giving insights into molecule-electrode coupling across series of molecules that can guide synthetic chemists in the design of new molecular motifs, particularly in the context of devices comprising large-area molecular junctions.
AB - This paper describes a simple model for comparing the degree of electronic coupling between molecules and electrodes across different large-area molecular junctions. The resulting coupling parameter can be obtained directly from current-voltage data or extracted from published data without fitting. We demonstrate the generalizability of this model by comparing over 40 different junctions comprising different molecules and measured by different laboratories. The results agree with existing models, reflect differences in mechanisms of charge transport and rectification, and are predictive in cases where experimental limitations preclude more sophisticated modeling. We also synthesized a series of conjugated molecular wires, in which embedded dipoles are varied systematically and at both molecule-electrode interfaces. The resulting current-voltage characteristics vary in nonintuitive ways that are not captured by existing models, but which produce trends using our simple model, providing insights that are otherwise difficult or impossible to explain. The utility of our model is its demonstrative generalizability, which is why simple observables like tunneling decay coefficients remain so widely used in molecular electronics despite the existence of much more sophisticated models. Our model is complementary, giving insights into molecule-electrode coupling across series of molecules that can guide synthetic chemists in the design of new molecular motifs, particularly in the context of devices comprising large-area molecular junctions.
KW - single-level model
KW - EGaIn
KW - self-assembled monolayers
KW - interface
KW - molecular electronics
UR - http://www.scopus.com/inward/record.url?scp=85139322908&partnerID=8YFLogxK
U2 - 10.1021/acsphyschemau.1c00029
DO - 10.1021/acsphyschemau.1c00029
M3 - Article
AN - SCOPUS:85139322908
SN - 2694-2445
VL - 2
SP - 179
EP - 190
JO - ACS Physical Chemistry Au
JF - ACS Physical Chemistry Au
IS - 3
ER -