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Interfacing Molecules to Electronic Materials
Artificial Enzymes Hydrogen generation, photovoltaics Steinberg-Yfrach et al. Nature 392, 479 (1998)
1. Make functional molecules 2. Wire molecules to electrodes Steps to bio/molecular electronics: 3. Make them function on electrodes like they do in solution 4. Make economically-viable devices
Test Case: Single Molecule Switch made from Oligo Aniline Insulator i V Conductor -2e - Insulator -2e - Single Molecule Switch?
Molecular electronics vs. solution charge transfer chemistry Charge transfer in nature in solution + ions. Charge transfer in molecular electronics electrode to electrode – No water/ions
1 2 LUMO HOMO CHARGED Why solvent + ions matter e-e- ENERGY e-e- LANDAUER MARCUS
Charge Transfer in DNA Barnett et al., Science (2001)
The Challenge Need to measure single molecule conductance in a conducting solution with independent control of charge state. How to do this?
Repeated break junction Xu and Tao, Science 301, (2003)
Wiring Single Molecules Reliably Cui et al. Science (2001) Xu and Tao, Science (2003) GOOD NEWS: 7000:1 G range – worst G theor /G meas is 3.3 BAD NEWS: All Landauer theory
Operating probes in electrolyte Rev. Sci. Instrum. 60, (1989) (DNA - Xu et al. Nanoletts ) Insulating layer
Controlling ion gradients/electric fields at an electrode surface Bigger ion gradient = Bigger electric field at molecule
Measuring transport as a function of oxidation state LOCAL FIELD SURFACE FIELD
Electrochemical Current Surface Potential, E S, V vs. Ag Molecular Conductance (nS) G=G MAX - a(E S -b) 2 InsulatorConductorInsulator TIP-SUBSTRATE V FIXED AT 50mV Ofer et al. JACS , 1990
Neutral molecule Current (nA) Tip-substrate bias (V) (NO IONS) FIX E S, VARY TIP FIELD Oxidized molecule E S =0.4V (H 2 SO 4 )
G=G max -a(E S -b) 2 E S (V) =E S - V =1.4 E S =0.3V E S =0.25V Tip-substrate bias (V) Current (nA) MOLECULE FIELD = SURFACE FIELD ± TIP FIELD
We have a two terminal switch!
Current (nA) V ts (Volts) E S (V vs. Ag Wire) --- But it will need more than one molecule: Bias sweeps Potential sweeps
Summary Made a low-voltage switch based on chemical knowledge, get NDR Probe role of fluctuations Roadmap for going from chemistry to molecular electronics
The moving charges (the microscopic particles) from the electric supply constitute an electric current Conventionally: The direction of the electric.
Unit 10 - Electricity. What is electricity? Electricity – form of energy caused by moving electrons.
AS Level Electricity - Circuits Taking Measurements The p.d. across a component in a circuit is measured in volts (V) using a voltmeter connected across.
By Valentin KulikovRegensburg Automated System for Combinatorial Synthesis and High-throughput Characterization of Polymeric Sensor Materials.
Electric Circuit A path on which electrons move continuously is called an electric circuit.
Of. and a to the in is you that it at be.
The. of and a to in is you that it he was.
CH 2: CHEMISTRY. Matter What is it? Anything that takes up space, has mass, and made up of atoms. What are the 3 states?
Chapter 13 Electricity. Charge and Force All matter is made of atoms that contain electrons, neutrons, and protons All matter is made of atoms that contain.
Chapter 2: The Chemical Level of Organization. KEY CONCEPT All Matter is made up of atoms Atoms join together to form chemicals with different characteristics.
Electricity & Magnetism Static, Currents, Circuits Magnetic Fields & Electro Magnets Motors & Generators.
Electrical Conductivity and pH MW – Molecules and Solutions.
Ionic Bonds For review pages Sections 8:1- 8:3 Forming Chemical Bonds The Formation and Nature of Ionic Bonds Names and Formulas for Ionic Compounds.
Electricity W Richards Worthing High School. Basic ideas… Electric current is when electrons start to flow around a circuit. We use an _________ to measure.
Electricity and Magnetism Flashcards. 1 No charge.
Practice and study guide for the test. ▪ Energy transformations-types of energy ▪ Machines- not needed for this test ▪ Motion- not needed for this test.
Conductivity A Conductor is a substance that allows electricity to pass through it. An Insulator is a substance that will not allow electricity to pass.
Electrochemical Sensors Electrochemical sensors are the most versatile and highly developed chemical sensors. They are divided into several types: Potentiometric.
Chemistry for Fuel Cells Alternative Energy and Fuel Cells Hocking Technical College July 23, 2007.
© 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their.
High Frequency Words List A Group 1. the of and.
Why Study Chemistry in Biology?. I. Atoms Definition: smallest particle of an element.
Copyright©2000 by houghton Mifflin Company. All rights reserved. 1 Reactions in Aqueous Solutions Chapter 7.
Unit 4 Test Review. Identify the following as covalent or ionic. 1.water (H 2 O) 2.salt (NaCl) 3.iron (II) sulfide (FeS) 4.calcium bromide (CaBr 2 ) 1.covalent.
CompoundSolubilityMelting Time Conductivity in solution Conductivity as solid.
1 of 22© Boardworks Ltd 2011 Extracting Metals by Electrolysis.
1 The Nature of Molecules Chapter 3. 2 Water Chemistry Water consists of an oxygen atom bound to two hydrogen atoms by two single covalent bonds. – stable.
Ionic Solutions Structure of liquids Interactions in ionic solutions Ion-ion interactions Debye-Huckel theory.
What is a Fuel Cell? Quite simply, a fuel cell is a device that converts chemical energy into electrical energy, water, and heat through electrochemical.
ElectricityElectricity. What do atoms contain? Charged particles.
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