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A Simple Theoretical Model to Study the Voltage Dependence of the Electronic Structure of Phenyl Ethylene Oligomers
Author(s) -
SIMÓNMANSO YAMIL,
GONZALEZ CARLOS,
MUJICA VLADIMIRO,
ARAY YOSSLEN,
MARQUEZA MANUEL
Publication year - 2003
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1292.004
Subject(s) - molecule , chemistry , work (physics) , computational chemistry , chemical physics , conjugated system , electric field , ethylene , molecular model , simple (philosophy) , voltage , polymer , physics , stereochemistry , thermodynamics , organic chemistry , quantum mechanics , philosophy , epistemology , catalysis
A bstract : Although very few measurements have appeared in the open literature and there seems to be a controversy about the existence of the NDR phenomenon in molecules, the prospects of building such systems have attracted significant attention. In the work reported in this paper we used a model based on DFT calculations of the electronic structure of the 2′‐amino‐4,4′‐di(ethynylphenyl)‐5′‐nitro‐1‐benzenethiolate molecule (previously reported to exhibit NDR behavior) in a capacitor‐like electric field that mimics the potential spatial profile of the junction. Our results suggest that in these systems, there seems to be a correlation between a substantial charge density rearrangement of the neutral bridge at a threshold voltage and the NDR behavior observed in previous experiments. Our results highlight the importance of inclusion of the field in the study of electrified interfaces. We applied this model to a fluorine‐substituted conjugated diethynylphenyl molecule and found that these calculations predict similar behavior. Results based on extended system calculations, including electrode‐molecule interactions, confirm the validity of the model based on the isolated molecule and suggest the use of these simple models to rationally design molecular devices with similar switching characteristics.