scholarly journals Heterobinuclear Light Absorber Coupled to Molecular Wire for Charge Transport across Ultrathin Silica Membrane for Artificial Photosynthesis

2018 ◽  
Vol 10 (37) ◽  
pp. 31422-31432 ◽  
Author(s):  
Georgios Katsoukis ◽  
Heinz Frei
Keyword(s):  
Charge Transport ◽  
Artificial Photosynthesis ◽  
Molecular Wire ◽  
Silica Membrane ◽  
Light Absorber

(Invited) Driving Metal Oxide Water Oxidation Catalyst By Visible Light Absorber Separated By an Ultrathin Proton Conducting Silica Membrane with Embedded Molecular Wires

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1845-1845
Author(s):  
Heinz Frei
Keyword(s):  
Charge Transfer ◽  
Metal Oxide ◽  
Visible Light ◽  
Water Oxidation ◽  
Oxide Catalyst ◽  
Molecular Wires ◽  
Core Shell ◽  
Molecular Wire ◽  
Silica Membrane ◽  
Light Absorber

We are developing nanoscale photosynthetic assemblies for coupling the catalysis for CO2 reduction with the H2O oxidation half reaction, taking an inorganic molecular approach that utilizes heterobinuclear units such as ZrOCoII as light absorber coupled to metal oxide catalyst. Artificial nanoscale photosystems are inspired by natural photosynthesis, the only existing technology for producing energy-dense chemicals on the terawatt scale, which has as key design feature the closing of the cycle of water oxidation and formation of primary reduction intermediates on the shortest possible length scale, the nanometer scale, while separating the incompatible redox environments by an ultrathin membrane. To accomplish the photocatalytic cycle of CO2 reduction by H2O under membrane separation, we are exploring a Co oxide – silica core-shell nanotube geometry.1-3 The inside surface of the Co oxide nanotube core provides the catalytic sites for H2O oxidation, which are separated from light absorber and sites of CO2 reduction on the outside by an ultrathin (2 nm) dense phase silica layer. The latter functions as proton conducting, O2 impermeable membrane.4 Tight, molecular-level control of charge transfer between light absorber and Co oxide nanotube catalyst is accomplished by oligo-para(phenylene vinylene) molecules with 3 aryl units embedded in the silica shell.5 This approach addresses the requirements of robustness and tunability of the electronic properties of the photosystem components with the objective of converting the maximum fraction of the solar photon energy into chemical energy of the fuel.6 The core-shell nanotube geometry offers the opportunity of assembling macroscale arrays of enormous numbers of nanotubes, each operating as independent photosynthetic unit while at the same time providing separation of evolving O2 and reduced CO2 products on all length scales from nano to centimeters.3 Detailed characterization of charge transfer between light absorber and Co oxide catalyst across the silica membrane was investigated by transient optical absorption spectroscopy and photoelectro-chemical methods using nanotube, spherical, or planar morphology depending on the type of experiment. Ultrafast optical monitoring allowed us to detect transient positive charge (hole) on the silica embedded molecular wire and revealed very efficient, 255 ps transfer to the Co oxide catalyst.7 Short circuit current measurements upon visible light sensitized hole injection using sensitizers with different redox potentials showed that charge transfer is controlled by the HOMO and LUMO energetics of the silica embedded wire molecules.4,5 Synthetic methods were developed for the accurate selection of embedded molecular wire loading and tuning of the concentration. Electron transfer processes of visible light excited ZrOCo or TiOCo light absorbers coupled to silica embedded wires and Co oxide catalyst are being explored by transient optical spectroscopy and photoelectrochemical methods, and will be the main topic of the presentation.8 Time permitting, recent application of ultrathin silica membrane with embedded molecular wires for separating incompatible catalytic environments of electronically coupled inorganic and microbial components will also be discussed.9 [1] Kim, W.; Edri, E.; Frei, H. Acc. Chem. Res. 49, 1634 (2016) [2] Kim, W.; McClure, B. A.; Edri, E.; Frei, H. Chem. Soc. Rev. 45, 3221 (2016) [3] Edri, E.; Aloni, S.; Frei, H., ACS Nano, submitted [4] Yuan, G.; Agiral, A.; Pellet, N.; Kim, W.; Frei, H. Faraday Discuss. 176, 233 (2014) [5] Edri, E.; Frei, H. J. Phys. Chem. C 119, 28326 (2015) [6] Frei, H. Curr. Opin. Electrochem. 2, 128 (2017) [7] Edri, E.; Cooper, J. K.; Sharp, I. D.; Guldi, D. M.; Frei, H. J. Am. Chem. Soc. 139, 5458 (2017) [8] Katsoukis, G.; Frei, H., to be submitted [9] Cornejo, J. A.; Sheng, H.; Edri, E.; Ajo-Franklin, C.; Frei, H., submitted

Charge transport through a molecular wire for flexible electronics

2012 ◽  
Vol 111 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Vijay Kr. Lamba ◽  
Suman J. Engles ◽  
R.S. Sawhney ◽  
C. Arora ◽  
Derick Engles
Keyword(s):  
Charge Transport ◽  
Flexible Electronics ◽  
Molecular Wire

ROLE OF ADENINE AND GUANINE SITES IN HOLE HOPPING IN DNA NANOWIRE

2009 ◽  
Vol 08 (03) ◽  
pp. 529-539
Author(s):  
INDERPREET KAUR ◽  
GIRISH S. KULKARNI ◽  
RAM AJORE ◽  
RICHA BHARADWAJ ◽  
BHANU PRAKASH KOTAMARTHI ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transport ◽  
Conformational Changes ◽  
Transport Mechanism ◽  
Molecular Wire ◽  
Charge Transport Mechanism ◽  
Close Analysis ◽  
Sequence Variations ◽  
Transfer Integrals

Transfer integrals for oligos with different bases have been calculated using INDO/Koopman's approximation to unveil the charge transport mechanism in DNA. The sequences, G(A) n G , n = 1, 2, …, 10; G(A) x G(A) y G , x + y = 9; and G(A) x G(A) y G(A) z G , x + y + z = 8, were employed to interpret the Guanine (G) and Adenine(A) hopping. Adenine hopping is found to be faster in G(A) n G sequences with longer Adenine bridges (n ≥ 3). Inserting G-bases in between G(A) 10 G led to a decrease in the value of transfer integrals. Close analysis has revealed that bridge closer to 3′-end forms a hopping bottleneck; however, the presence of bridge at 5′-end enhances the charge transfer through A-hopping. Further insertion of single G sites in G(A) x G(A) y G (where x + y = 9) reduces the transfer integrals, thus explaining the hampering of A-hopping. Hence, sequences of the type G(A) n G , n > 3, are better suited for their application as molecular wire. Finally, studies on the effect of flipping of bases, i.e. flipping G:C to C:G on transfer integrals, have revealed that helical distortions and conformational changes due to sequence variations lead to changes in coupling, which is highly unpredictable.

Membranes for artificial photosynthesis

2017 ◽  
Vol 10 (6) ◽  
pp. 1320-1338 ◽  
Author(s):  
Sakineh Chabi ◽  
Kimberly M. Papadantonakis ◽  
Nathan S. Lewis ◽  
Michael S. Freund
Keyword(s):  
Charge Transport ◽  
Artificial Photosynthesis ◽  
Electrochemical Potential ◽  
Potential Gradients

Membrane-based architectures enable optimization of charge transport and electrochemical potential gradients in artificial photosynthesis.

Molecular Wires: Charge Injection, Charge Transport and Motion Mechanisms in DNA

2001 ◽  
Vol 679 ◽  
Author(s):  
Yu. A. Berlin ◽  
A. L. Burin ◽  
A. Nitzan ◽  
V. Mujica ◽  
A. Xue ◽  
...  
Keyword(s):  
Charge Transport ◽  
First Principles ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Charge Injection ◽  
Molecular Wires ◽  
Molecular Wire ◽  
Dna Duplex ◽  
Experimental Findings ◽  
Hopping Model

The use of the DNA duplex as a molecular wire is discussed with particular attention to recent experimental findings. Experimental studies of photo-excited hole dynamics in DNA can be understood within the phenomenological hopping model. However a microscopic first principles approach requires taking into account the interaction between charge and duplex degrees of freedom. The nature of possible metallic native DNA behavior is discussed.

scholarly journals Identification of the current path for a conductive molecular wire on a tripodal platform

Nanoscale ◽  
2016 ◽  
Vol 8 (20) ◽  
pp. 10582-10590 ◽  
Author(s):  
M. A. Karimi ◽  
S. G. Bahoosh ◽  
M. Valášek ◽  
M. Bürkle ◽  
M. Mayor ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Charge Transport ◽  
Molecular Wire ◽  
Phenylene Ethynylene ◽  
Synthesis Route ◽  
Transport Measurements ◽  
Current Path ◽  
Chemical Synthesis Route

We present charge transport measurements and calculations and outline the chemical synthesis route for a new tripodal platform based on a rigid 9,9′-spirobifluorene equipped with a phenylene-ethynylene wire.

CHARGE TRANSPORT THROUGH THIOPHENE BITHIOL MOLECULE AS A MOLECULAR WIRE

2005 ◽  
Vol 04 (04) ◽  
pp. 1001-1014 ◽  
Author(s):  
SEIFOLLAH JALILI ◽  
FERESHTEH MORADI
Keyword(s):  
Density Functional Theory ◽  
Quantum Mechanics ◽  
Charge Transport ◽  
Density Functional ◽  
Quantum Mechanical ◽  
Molecular Wire ◽  
Functional Theory ◽  
The Right ◽  
Non Equilibrium Green’S Function ◽  
Left Lead

The conductance properties of the thiophene bithiol molecular wire, a nano-wire connecting two metallic electrodes, were investigated using quantum-mechanical based methods such as Density Functional Theory, in conjunction with non-equilibrium Green's function formalism. Using the quantum mechanics methods, the Hamiltonians of the three main parts of system, i.e. the right lead, the device, the left lead and conductance properties of this molecular wire such as I-V curve, were calculated.

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