Mono-exponential Current Attenuation with Distance across 16 nm Thick Bacteriorhodopsin Multilayers

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Hauptverfasser: Chryssikos, Domenikos, Fereiro, Jerry A., Rojas, Jonathan, Bera, Sudipta, Tüzün, Defne, Kounoupioti, Evanthia, Pereira, Rui N., Pfeiffer, Christian, Khoshouei, Ali, Dietz, Hendrik, Sheves, Mordechai, Cahen, David, Tornow, Marc
Format: Preprint
Veröffentlicht: 2024
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author Chryssikos, Domenikos
Fereiro, Jerry A.
Rojas, Jonathan
Bera, Sudipta
Tüzün, Defne
Kounoupioti, Evanthia
Pereira, Rui N.
Pfeiffer, Christian
Khoshouei, Ali
Dietz, Hendrik
Sheves, Mordechai
Cahen, David
Tornow, Marc
author_facet Chryssikos, Domenikos
Fereiro, Jerry A.
Rojas, Jonathan
Bera, Sudipta
Tüzün, Defne
Kounoupioti, Evanthia
Pereira, Rui N.
Pfeiffer, Christian
Khoshouei, Ali
Dietz, Hendrik
Sheves, Mordechai
Cahen, David
Tornow, Marc
contents The remarkable ability of natural proteins to conduct electricity in the dry state over long distances remains largely inexplicable despite intensive research. In some cases, a (weakly) exponential length-attenuation, as in off-resonant tunneling transport, extends to thicknesses even beyond 10 nm. This report deals with such charge transport characteristics observed in self-assembled multilayers of the protein bacteriorhodopsin (bR). About 7.5 nm to 15.5 nm thick bR layers were prepared on conductive titanium nitride (TiN) substrates using aminohexylphosphonic acid and poly-diallyl-dimethylammonium electrostatic linkers. Using conical EGaIn top contacts, an intriguing, mono-exponential conductance attenuation as a function of the bR layer thickness with a small attenuation coefficient $β\approx 0.8 \space {\rm nm}^{-1}$ is measured at zero bias. Variable-temperature measurements using evaporated Ti/Au top contacts yield effective energy barriers of about 100 meV from fitting the data to tunneling, hopping, and carrier cascade transport models. The observed temperature-dependence is assigned to the protein-electrode interfaces. The transport length and temperature dependence of the current densities are consistent with tunneling through the protein-protein and protein-electrode interfaces, respectively. Importantly, our results call for new theoretical approaches to find the microscopic mechanism behind the remarkably efficient, long-range electron transport within bR.
format Preprint
id arxiv_https___arxiv_org_abs_2408_09289
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mono-exponential Current Attenuation with Distance across 16 nm Thick Bacteriorhodopsin Multilayers
Chryssikos, Domenikos
Fereiro, Jerry A.
Rojas, Jonathan
Bera, Sudipta
Tüzün, Defne
Kounoupioti, Evanthia
Pereira, Rui N.
Pfeiffer, Christian
Khoshouei, Ali
Dietz, Hendrik
Sheves, Mordechai
Cahen, David
Tornow, Marc
Biological Physics
Materials Science
Soft Condensed Matter
Chemical Physics
The remarkable ability of natural proteins to conduct electricity in the dry state over long distances remains largely inexplicable despite intensive research. In some cases, a (weakly) exponential length-attenuation, as in off-resonant tunneling transport, extends to thicknesses even beyond 10 nm. This report deals with such charge transport characteristics observed in self-assembled multilayers of the protein bacteriorhodopsin (bR). About 7.5 nm to 15.5 nm thick bR layers were prepared on conductive titanium nitride (TiN) substrates using aminohexylphosphonic acid and poly-diallyl-dimethylammonium electrostatic linkers. Using conical EGaIn top contacts, an intriguing, mono-exponential conductance attenuation as a function of the bR layer thickness with a small attenuation coefficient $β\approx 0.8 \space {\rm nm}^{-1}$ is measured at zero bias. Variable-temperature measurements using evaporated Ti/Au top contacts yield effective energy barriers of about 100 meV from fitting the data to tunneling, hopping, and carrier cascade transport models. The observed temperature-dependence is assigned to the protein-electrode interfaces. The transport length and temperature dependence of the current densities are consistent with tunneling through the protein-protein and protein-electrode interfaces, respectively. Importantly, our results call for new theoretical approaches to find the microscopic mechanism behind the remarkably efficient, long-range electron transport within bR.
title Mono-exponential Current Attenuation with Distance across 16 nm Thick Bacteriorhodopsin Multilayers
topic Biological Physics
Materials Science
Soft Condensed Matter
Chemical Physics
url https://arxiv.org/abs/2408.09289