Massachusetts Institute of Technology

Molecular Displays, Inc.

Harvard College

Gte Laboratories Incorporated

Mass. Institute of Technology

Mark S Wrighton

Henry S White, Jr

Robert M Buchanan

Gary S Calabrese

Gregg P Kittlesen

Nicholas Leventis

Dana C Bookbinder

George M Whitesides

Chad A Mirkin

James J Hickman

Steven W Kaiser

Joseph E Lester

Howard McKinzie

Nathan S Lewis

David Ofer

James A Bruce

Paul E Laibinis

Raymond N Dominey

James W Thackeray

James R Valentine

Arthur B Ellis

A display having an array of matrix addressable pairs of electrodes mounted face up on the same substrate. The pairs of electrodes are derivatized with either electrochromic materials or electroluminescent material to form the pixels of the display. In the electrochromic embodiment of the invention, a layer of a solid polymer electrolyte is included. The air of electrodes may also be left clean of derivatizing material, but with an electroluminescent substance dissolved in the solid polymer electrolyte. An electrochemiluminescent embodiment is also provided where the electrochemiluminescent substance can be dissolved in the solid polymer electrolyte. A method of patterning the electrolyte layer to form relatively nonconductive borders around each of the pairs by selective exposure of the electrolyte layer in the region of the border to electromagnetic radiation to cause permanent change in the chemical composition of the electrolyte so that the exposed border regions are rendered relatively non-conductive is also provided. An electrically reconfigurable photomask having an area comprised of an arrangement of electrochromic covered electrode pairs constituting pixels, the opacity and transmissivity of which may be controlled by application of an electrical bias to yield complete control over the transmissivity and opacity of each pixel of the areas, is also provided.

Electrochromic, electroluminescent and electrochemiluminescent displays

Self-assembly of a chemically insensitive redox material, such as ferrocenyl thiol, and a chemically sensitive redox material, such as a quinone thiol, onto microelectrodes forms the basis for a two-terminal, voltammetric microsensor having reference and sensor functions on the same electrode. Detection is based on measuring the potential difference of current peaks for oxidation and reduction of the reference (ferrocene) and indicator (quinone) in aqueous electrolyte in a two-terminal, linear sweep voltammogram using a counterelectrode of relatively large surface area. Use of microelectrodes modified with monolayer coverages of reference and indicator molecules minimizes the size of the counterelectrode and the perturbation of the solution interrogated. Key advantages are that the sensor requires no separate reference electrode and the sensor functions as long as current peaks can be located for reference and indicator molecules.

Two-terminal voltammetric microsensors

A display having an array of matrix addressable pairs of electrodes mounted face up on the same substrate. The pairs of electrodes are derivatized with either electrochromic materials or electroluminescent material to form the pixels of the display. In the electrochromic embodiment of the invention, a layer of a solid polymer electrolyte is included. The air of electrodes may also be left clean of derivatizing material, but with an electroluminescent substance dissolved in the solid polymer electrolyte. An electrochemiluminescent embodiment is also provided where the electrochemiluminescent substance can be dissolved in the solid polymer electrolyte. A method of patterning the electrolyte layer to form relatively non-conductive borders around each of the pairs by selective exposure of the electrolyte layer in the region of the border to electromagnetic radiation to cause permanent change in the chemical composition of the electrolyte so that the exposed border regions are rendered relatively non-conductive is also provided. An electrically reconfigurable photomask having an area comprised of an arrangement of electrochromic covered electrode pairs constituting pixels, the opacity and transmissivity of which may be controlled by application of an electrical bias to yield complete control over the transmissivity and opacity of each pixel of the areas, is also provided.

Several types of new microelectronic devices including diodes, transistors, sensors, surface energy storage elements, and light-emitting devices are disclosed. The properties of these devices can be controlled by molecular-level changes in electroactive polymer components. These polymer components are formed from electrochemically polymerizable material whose physical properties change in response to chemical changes, and can be used to bring about an electrical connection between two or more closely spaced microelectrodes. Examples of such materials include polypyrrole, polyaniline, and polythiophene, which respond to changes in redox potential. Each electrode can be individually addressed and characterized electrochemically by controlling the amount and chemical composition of the functionalizing polymer. Sensitivity of the devices may be increased by decreasing separations between electrodes as well as altering the chemical environment of the electrode-confined polymer. These very small, specific, sensitive devices provide means for interfacing electrical and chemical systems while consuming very little power.

Molecule-based microelectronic devices

Novel microelectrochemical devices are provided which consist of closely spaced microelectrodes coated with metal ion based inorganic redox active material such as oxides or mixed oxides of any of the following transition metals: W, Ni, Ru, Co, Rh, Ir, Nb, Mo, V, or any other metal that undergoes a change in electrical conductivity upon electrochemical oxidation or reduction, in contact with an electrolyte. Additionally, other metal based redox materials whose conductivity changes as a function of the movement of ions into or out of the material can be used in the construction of microelectronic devices, for example, Prussian Blue, Fe.sub.4 [Fe(CH).sub.6 ].sub.3. 'Metal ion-based microelectrochemical devices' encompasses all devices based on an inorganic redox active material which incorporate an active 'gate' region or 'channel', or exhibit rectification. Included in this classification are devices analogous to diodes, field effect transistors, p-n-p transistors, and n-p-n transistors, and pH sensors, among others. A number of specific examples of transistors and sensors are described in detail.

Microelectrochemical devices based on inorganic redox active material

Electrochemical devices constructed according to the present invention can be used to convert an ion flux into an electric current for determination of ion concentration. The devices are operated without the need for a reference electrode and are specific based on known ion transfer agents. Operation of the devices involves the use of pairs of electrodes modified with electroactive redox materials overlaid with ion selective coatings. An applied potential between a pair of appropriately modified electrodes results in the flow of an electric current between the electrodes which is dependent on the concentration of the ion to be sensed. Devices constructed by combining electrodes overlaid with electroactive polymers and different ion selective films allow simultaneous determination of diverse ions. For example, these devices are useful for measuring the concentration of total cations, total anions, H.sup.+, Li.sup.+, K.sup.+, Ca.sup.2+, Na.sup.+, HCO.sub.3.sup.-, Cl.sup.-, other cations and anions, and combinations thereof. The devices are small and stable enough to be used in vivo, for example, as blood monitoring means, or in large scale water quality monitoring or purification/separations techniques.

Amperometric electrochemical ion sensors and method for determining ion

Several types of new microelectronic devices including diodes, transistors, sensors, surface energy storage elements, and light-emitting devices are disclosed. The properties of these devices can be controlled by molecular-level changes in electroactive polymer components. These polymer components are formed from electrochemically polymerizable material whose physical properties change in response to chemical changes, and can be used to being about an electrical connection between two or more closely spaced microelectrodes. Examples of such materials include polypyrrole, polyaniline, and polythiophene, which respond to changes in redox potential. Each electrode can be individually addressed and characterized electrochemically by controlling the amount and chemical composition of the functionalizing polymer. Sensitivity of the devices may be increased by decreasing separations between electrodes as well as altering the chemical environment of the electrode-confined polymer. These very small, specific, sensitive devices provide means for interfacing electrical and chemical systems while consuming very little power.

Very stable, polymer-based electrochemical devices, formed by polymerization of thiophene or a derivative such as 3-methylthiophene which is durable in an aqueous electrolyte over a wide pH range, which respond rapidly to chemical or electrical signals, are disclosed. In one embodiment, the device functions as an extremely sensitive sensor which measures changes in chemical concentration or pH. For example, a poly-3-methylthiophene-based device is sensitive to as little as 8.times.10.sup.-16 moles of an oxidant which reversibly interacts with the polymer, including gas phase oxidants such as I.sub.2. In a variation of the polymer-based device, a catalyst such as a noble metal or an enzyme, is dispersed on or within the conducting polymer matrix so that the device is responsive to chemicals such as H.sub.2 and O.sub.2 which the polymer would otherwise respond very slowly to. In a second embodiment, a polymer-based electrochromic device consists of polymer-coated microelectrodes which are individually addressed. Very high resolution is achieved by separating the microelectrodes by distances on the order of 10,000 Angstroms. In still another embodiment, the polymer-based device functions as a capacitor with an energy density as high as 200-300 J/cm.sup.3 which can operate at frequencies as high as 100 Hz. Large polymer-based capacitors are useful for storage of solar energy or as automobile batteries. Microcapacitors may be incorporated into conventional integrated circuit designs.

Microelectrochemical devices

Methods, materials and apparatus for production of hydrogen peroxide are disclosed. In one preferred embodiment, high surface area circulating elements derivatized with a quinone catalyst are reduced in an electrolytic cell where the cathode may also be derivatized with a quinone catalyst and a solution quinone at low concentration is used as a mediator. Once reduced, the circulating elements are separated and used to form hydrogen peroxide from molecular oxygen in an aqueous, electrolyte-free, environment. The circulating elements can be cycled repeatedly. Particular, novel naphthoquinone compounds are also disclosed.

Production of hydrogen peroxide

An apparatus for the production of hydrogen peroxide is disclosed. In one preferred embodiment, high surface area circulating elements derivatized with a quinone catalyst are reduced in an electrolytic cell where the cathode may also be derivatized with a quinone catalyst and a solution quinone at low concentration is used as a mediator. Once reduced, the circulating elements are separated and used to form hydrogen peroxide from molecular oxygen in an aqueous, electrolyte-free, environment. The circulating elements can be cycled repeatedly. Particular, novel naphthoquinone compounds are also disclosed.

Apparatus for production of hydrogen peroxide

Synthesis of N,N'-dialkyl-4'bipyridinium reagents

A variety of redox mediating agents employing bipyridinium reagents and such reagents in conjunction with dispersed noble metals, such as platinium, are disclosed as coatings for substrates and electrodes. The agents may be charged by an applied voltage or by photoelectric effects or may be equilibrated with hydrogen. The agents are useful in reducing biological materials and electrolytic hydrogen production.

Redox mediation and hydrogen-generation with bipyridinium reagents

Sustained conversion of low energy visible or near i.r. light (&gt;1.25 eV) to electrical energy has been obtained using wet photoelectrochemical cells where there are no net chemical changes in the system. Stabilization of n-type semi-conductor anodes of CdS, CdSe, CdTe, GaP, GaAs and InP to photoanodic dissolution is achieved by employing selected alkaline solutions of Na.sub.2 S, Na.sub.2 S/S, Na.sub.2 Se, Na.sub.2 Se/Se, Na.sub.2 Te and Na.sub.2 Te/Te as the electrolyte. The oxidation of (poly) sulfide, (poly)selenide or (poly)telluride species occurs at the irradiated anode, and reduction of polysulfide, polyselenide or polytelluride species occurs at the dark Pt cathode of the photoelectrochemical cell. Optical to electrical energy conversion efficiencies approaching 15% at selected frequencies have been observed in some cells. The wavelength for the onset of photocurrent corresponds to the band gap of the particular anode material used in the cell.

Growing community of inventors

Winchester, MA, United States of America

Mark S Wrighton