KR20070103376A - Solid state photosensitive devices which employ isolated photosynthetic complexes - Google Patents

Abstract

Solid state photosensitive devices including photovoltaic devices are provided which comprise a first electrode and a second electrode in superposed relation; and at least one isolated Light Harvesting Complex (LHC) between the electrodes. Preferred photosensitive devices comprise an electron transport layer formed of a first photoconductive organic semiconductor material, adjacent to the LHC, disposed between the first electrode and the LHC; and a hole transport layer formed of a second photoconductive organic semiconductor material, adjacent to the LHC, disposed between the second electrode and the LHC. Solid state photosensitive devices of the present invention may comprise at least one additional layer of photoconductive organic semiconductor material disposed between the first electrode and the electron transport layer; and at least one additional layer of photoconductive organic semiconductor material, disposed between the second electrode and the hole transport layer. Methods of generating photocurrent are provided which comprise exposing a photovoltaic device of the present invention to light. Electronic devices are provided which comprise a solid state photosensitive device of the present invention.

Description

Solid state photosensitive device using insulated photosynthetic composite {SOLID STATE PHOTOSENSITIVE DEVICES WHICH EMPLOY ISOLATED PHOTOSYNTHETIC COMPLEXES}

Field of invention

The present invention is a first electrode and a second electrode in an overlapping relationship; And one or more insulated photosynthetic complexes (Light Harvesting Complex (LHC), such as PSI (from light system I, for example spinach)), and / or LH2 (condensing complex 2, purple bacteria) between the electrodes. generally associated with a photosensitive device in a solid state, including a photovoltaic device, which includes exposing the photoelectric device of the invention to light. A method for supplying is described An electronic device comprising a solid state photosensitive device according to the present invention is described.

Background technology

Photosynthesis is a biological process that converts electromagnetic energy into electrochemical energy through light and dark reactions. Photosynthesis occurs in differentiated organelles in higher plants and green algae called chloroplasms. Chloroplasm is enclosed in a double membrane and contains thylakoid, which consists of a layered membrane disk (Grana) and a non-layered membrane disk (stroma). The thylakoid membrane contains two important photosynthetic components, which are light system I and light system II, denoted PSI and PSII, respectively.

Electrical studies of photosynthetic complexes were initiated by Lee and Greenbaum at Oak Ridge National Lab [Lee, L, et. al , Phys . Rev , Lett . 79, 3294 (1997); Greenbaum, E., Science 230, 1373 (1985); Lee, L, et al ., J. Phys . Chem . B 104, 2439 (2000). These researchers chemically precipitated Pt into the electron donor sites on the composite surface and then produced H ₂ using a platinum coated composite. They also observed photovoltage using a Kelvin force microscope and measured the orientation statistics of the complex on the hydrophilic substrate [Greenbaum, E., Bioelectrochemistry and Bioenergetics, 21: 171, 1989; Greenbaum, E., J. Phys. Chem., 94: 6151, 1990; Lee, L, Proc. Natl. Acad. Sci. USA, 92: 1965, 1995; Lee, I., et al., 11 (4): 375, 1996. Also, United States Patent No. 6, 162,278, entitled " Photobiomolecular Deposition of Metallic Particles and Films ", Hu, December 19, 2000].

The manufacture of molecular circuits currently goes beyond the resolution of conventional patterning techniques such as electron beam lithography. However, the positioning of molecules with sub-nanometer precision is virtually routine and crucial for the operation of the photosynthetic complex. The photosynthetic complex is optimized to flow energy, for example, from the molecular antenna to the center of the reaction where the charge is generated. Natural protein scaffolds control the precise placement and orientation of optically and electronically active molecular components. Photosynthetic complexes include a combination of size and functionality optimized by evolution. In typical complexes such as those found in the purple bacterium Synechococcus Elongatus , absorbed photons are collected at a total quantum yield of 98% within 100 ps of photon absorption. Photovoltaic power of 1V occurs throughout the complex, with power conversion efficiency of about 40% [Schubert, WD, et al , J. MoI . Biol . 272, 741-768 (1997). In fact, natural biomolecular complexes outperform the best artificial optoelectronic devices.

However, the prior art does not describe a highly efficient light conversion structure for capturing incident light and converting the incident light into electrical energy suitable for nanometric electronic devices. There is a need in the art for a solid state photosensitive device that interfaces with conventional electronics, including photosynthetic molecular components based on proteins and photovoltaic devices that power the circuit by converting light into photocurrent.

Accordingly, the primary object of the present invention described herein is to incorporate the light collecting composite into a solid state into a functional device comprising a device using a single photosynthetic composite. The prior art also did not anticipate organic layers incorporated into the solid state photosensitive device comprising the light collecting composite as described herein.

Summary of the Invention

The photosensitive device in the solid state includes a first electrode 2 and a second electrode 4 in an overlapping relationship; And at least one insulated light collecting composite (LHC) 6 between the electrodes.

An electron transport 8 layer disposed between the first electrode 2 and the LHC 6 and adjacent the LHC 6 and formed of a first photoconductive organic semiconductor material; And a hole transport layer 10 disposed between the second electrode 4 and the LHC 6 and adjacent to the LHC 6 and formed of a second photoconductive organic semiconductor material.

Another embodiment of the invention is one or more additional photoconductive organic semiconductor material layers 12 disposed between the first electrode 2 and the electron transport layer 8, and / or the second electrode 4 and the hole transport layer 10. Disposed between and includes at least one layer of photoconductive organic semiconductor material 14.

Embodiments of the present invention provide that an electron and / or exciton blocking layer 16 is disposed between the second electrode 40 and the hole transport layer 10.

In the solid state photosensitive device of the present invention, the second electrode 2 is substantially transparent to incident light (λ to 800 nm), and the photoconductive organic semiconductor material between the electrodes 2 and 4 is applied to incident light. It is preferable that the second electrode 4 be transparent and substantially reflect the incident light.

Embodiments of the present invention provide a solid state photosensitive device wherein the distance 18 between the LHC and each electrode is about [lambda] / 4n, where [lambda] is the principal wavelength of light absorbed by the LHC and n is the LHC and Refractive index of the material between the electrodes 2 or 4).

In the photosensitive device in the solid state, it is preferable that the first electrode 2 is further connected with the second electrode 4 through the circuit 20.

A method is provided for generating a photocurrent comprising exposing the photovoltaic device of the invention to light.

An electronic device is provided incorporating one or more solid state photosensitive devices of the present invention.

Detailed description of the invention

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications and patents mentioned in this specification are incorporated by reference.

It is a general object of the present invention to provide a high efficiency light conversion for capturing incident light and converting the incident light into electrical energy. The invention relates in particular to a solid state photosensitive device comprising a first electrode and a second electrode in an overlapping relationship and at least one insulated light collecting composite (LHC) between the electrodes. The photosensitive device of the present invention includes a photoelectric device that supplies power to a circuit by converting light into a photocurrent. The present invention is directed to various embodiments of interfacing photosynthetic molecular components based on proteins with conventional electronic products. The present invention is particularly suitable for nanometer scale photosensitive devices, including sensors, photovoltaic cells and related devices. It is a primary object of the present invention to incorporate the light collecting composite into a functional device comprising a device using a single photosynthetic composite. Nanometer scale photodetectors and photovoltaic cells are provided for nanometric devices.

With reference to FIG. 1, the solid state photosensitive device of the present invention, in particular, includes a first electrode 2 and a second electrode 4 in an overlapping relationship; And at least one insulated LHC 6 between the electrodes. Embodiments of the invention include, for example, an electron transport layer 8 adjacent the LHC 6 and disposed between the first electrode 2 and the LHC 6 and formed of a first photoconductive organic semiconductor material; And a hole transport layer 10 adjacent the LHC 6 and disposed between the second electrode 4 and the LHC 6 and formed of a second photoconductive organic semiconductor material. An alternative embodiment of the invention is one or more additional photoconductive organic semiconductor material layers 12 and / or the second electrode 4 and the hole transport layer disposed between the first electrode 2 and the electron transport layer 8. 10) one or more additional photoconductive organic semiconductor material layers 14 disposed therebetween.

Referring to FIG. 2, an embodiment of the invention is provided in which an exciton blocking layer 16 is disposed between the second electrode 4 and the hole transport layer 10. In the solid state photosensitive device of the present invention, the first electrode 2 is substantially transparent to incident light (λ to 800 nm), the photoconductive organic semiconductor material between the electrodes is substantially transparent to incident light, and the second electrode (4) preferably reflects substantially the incident light. Embodiments of the invention provide that the distance 18 between the LHC and each electrode is about [lambda] / 4n, where [lambda] is the peak wavelength of light absorbed by the LHC, and n is the LHC and respectively Is the refractive index of the material between the electrodes. In the photosensitive device in the solid state, it is preferable that the first electrode 2 is further connected with the second electrode 4 through the circuit 20.

Evolutionary optimization of photosynthetic complexes has been especially developed to provide efficient power conversion. LHC places the photosynthetic agent at sub-nanometer precision and provides a two-molecule electronic component in the solid state photosensitive device of the present invention. The precisely placed molecules in the LHC component of the invention interact (like antennas and receivers) through dipole-dipole coupling. This coupling is very sensitive to molecular position and orientation. Subminiature scale lowers switching energy and transit time. As used herein, the term "condensing complex (LHC)" refers to, for example, PSI (photosystem I, eg from spinach), and / or LH2 (condensation complex 2, derived from purple bacteria). , P., et al , Biochim . Biophys . Acta 1365, 175 (1998); Lee, L, et al , Phys . Rev. Lett . 79, 3294 (1997); Schubert, WD, et al , J. MoI Biol . 272, 741-768 (1997). Such complexes are commercially available, for example, from PROTEIN LABS Inc., 1425 Russ Blvd., Suite T-107C, San Diego, CA 92101. Photosystem I (PSI) is a preferred LHC in the structure of the solid state photosensitive device of the present invention, including, for example, a logic device. For example, the PSI used according to the invention will preferably be prepared from, for example, spinach chloroplasts. PSI is a protein-chlorophyll complex with diode properties and is part of the photosynthetic machinery in the thylakoid membrane. It is oval shaped and has dimensions of about 5 x 6 nanometers. PSI is used herein to create nanometer circuits. The PSI reaction center / core antenna complex contains about 40 chlorophylls per photoactive reaction center pigment (P700). The chlorophyll molecule is used as an antenna that absorbs photons and delivers photon energy to P700, where this energy is captured and used to accelerate the photochemical reaction. In addition to P700 and antenna chlorophyll, the PSI complex contains multiple electron acceptors. Electrons released from P700 are transported from the reducing end of the PSI to the terminal receptor via an intermediate receptor, and electrons are transported across the thylakoid membrane. Electrons move to the stromal surface, and holes remain on the lumen surface of the PSI. After absorption of photons, energy is sent from the base of the complex to the main electron donor. After exciton decomposition, the electrons are moved to the opposite surface through three Fe 4 S 4 clusters. Electrons on the upper (stromal) surface and holes on the lower (lumen) surface are obtained as a result. Thus, due to the regulated nature of electron transfer, the composite preferably has the correct orientation when deposited on a substrate. Lee et al. Have determined that PSI complexes preferentially deposit on hydrophilic surfaces with electron transport vectors perpendicular to the substrate [ Phys . Rev. Lett . 79, 3294-3297 (1997).

For the PSI reaction center, the midpoint oxidization potential produced by the main electron donor (P700) is about +0.4 V, and the corresponding reduction potential produced by the electron acceptor (4Fe-4S center) is about −. 0.7 V. Thus, the PSI reaction center is a photodiode (unidirectional electron flow) and a solar cell of nanometer size (about 6 nm).

Another important complex is Rhodopseudomanas, which absorbs solar radiation. acidophila ). It is also insulated and crystallized [Cogdell, RJ, et al ., Biochimica et Biophysica Acta 722, 427-435 (1984); McDermott, G., et al ., Nature 374, 517-521 (1995); Papiz, MZ, et al , Journal of Molecular Biology 209, 833-835 (1989); Fenna, RE, et . Al. , Nature 258, 573-577 (1975). The photosynthetic machinery of these bacteria is biologically optimized to flow energy into the reaction center at 98% total quantum yield within 100ps [Sundstrom, V., et al., Journal of Physical Chemistry B 103, 2327-2346 (1999); Renger, T., et al., Physics Reports 343, 137-254 (2001). Protein serves several purposes. This gives rigidity to the photosynthetic unit, fixes the pigment in place and provides a heat sink for extra energy. Photosynthetic units have also evolved to protect against degeneration, for example one pigment known as a carotenoid improves the stability of the photosynthetic unit by quenching the triplet state (which avoids the possibility of reactive singlet oxygen formation through triplet-triplet extinction). Increase significantly. Such photosynthetic complexes can be used as components of the photovoltaic cells and photodetectors described herein.

The well characterized two-molecule complex photosystem I (PSI), derived from the purple bacterium Sinecococcus elongatus, is another example of an LHC for use in the solid state photosensitive device [Schubert, WD, et al., J. MoI. Biol. 272, 741-768 (1997). PSI preferentially forms trimmers. Charge generation occurs at the center of the reaction at the center of each PSI monomer. Approximately 100 chlorophyll molecules surround the reaction center. These molecules absorb light and move it to the center, acting as a highly efficient antenna. In addition, there are 15-25 carotenoid molecules that absorb light at wavelengths at which the chlorophyll molecule has low sensitivity. Carotenoids protect the structure against oxidation by quenching the formation of singlet oxygen. PSI can be present on its own or in combination with additional light collecting composites, thereby improving its absorption at low light levels.

Since the LHC reaction center is a pigment-protein complex responsible for photosynthetic conversion of light energy into electronic energy, this reaction center is now used as a constituent in various other kinds of devices as described herein.

The present invention provides a solid state photosensitive device comprising one or more insulated LHCs that are electronically connected to the first electrode and are independently electronically connected to the second electrode. A solid state photosensitive device is also provided that includes at least one insulated LHC that is electronically connected to the first electrode and is independently electronically connected to the second electrode, wherein the first electrode is further connected to the second electrode by a circuit. to provide. The solid state photosensitive device of the present invention includes a first electrode and a second electrode in an overlapping relationship; And at least one insulated LHC between the electrodes. The present system provides a photosynthetic system, which not only uses the light harvesting and charge separation processes in photosynthesis, but also acts as an efficient photo-current converter in molecular devices.

Electrodes or contacts used in the solid state photosensitive device of the present invention are an important consideration. It is desirable to allow the maximum amount of ambient electromagnetic radiation from outside the device to be allowed in the photoconductively active inner region. In other words, it is desirable to obtain electromagnetic radiation that can be converted to electricity by photoconductive absorption. This often indicates that one or more electrical contacts should absorb minimally and reflect incident electromagnetic radiation. In other words, these contacts should be substantially transparent. As used herein, “electrode” and “contact” refer only to a layer that provides a medium for delivering photogenerated power to an external circuit or for providing a bias voltage to a device. In other words, the electrode or contact provides an interface between the photoconductive active region of the photosensitive device in the solid state and other means for transporting charge carriers to or from wires, leads, traces or external circuits. The term “charge transfer layer” is similar to an electrode, but a charge transfer layer refers to a layer that differs from an electrode in that it only transfers charge carriers from one subsection of the device to an adjacent subsection. As used herein, an organic layer or a plurality of successive different material layers of a material is referred to as "transparent" when it allows the layer or layers to transmit at least 50% of the ambient electromagnetic radiation at the corresponding wavelengths through which they are transmitted. . Similarly, layers that allow some, but less than 50%, transmission of ambient electromagnetic radiation at corresponding wavelengths are referred to as "translucent".

The electrode or contact is generally a metal or "metal substitute". As used herein, the term "metal" refers to a metal alloy that is an elementally pure metal, such as Mg, and a material comprising two or more elementally pure metals, such as Mg and Ag (denoted Mg: Ag). Also used to include all. Herein, "metal substitutes" refer to materials which are not metals within the normal definition but which have the same properties as the desired metals in certain suitable applications. Metal substitutes for commonly used electrodes and charge transfer layers are transparent, such as doped wide bandgap semiconductors such as indium tin oxide (ITO), gallium indium tin oxide (GITO), and zinc indium tin oxide (ZITO). It will include a conductive oxide. In particular, ITO is a highly doped degenerate n + semiconductor with an optical bandgap of approximately 3.2 eV, which is transparent for wavelengths greater than approximately 3,900 Hz. Another suitable metal substitute material is permeable conductive polymer polyanaline (PANI) and chemical relatives thereof. Metal substitutes may also be selected from a wide variety of nonmetallic materials, where “nonmetals” is meant to include a wide variety of materials, provided the material does not contain a chemically unbound form of metal. When a metal is present in chemically unbound form, alone or in combination with one or more other metals as an alloy, this metal may alternatively be present in its metal form or may be referred to as a "free metal". Accordingly, the metal substitute electrode of the present invention may sometimes be referred to as "metal-free", where the term "metal free" is clearly a material that does not contain metal in its chemically unbound form. It means to include. Free metals generally take the form of metal bonds, which are thought to be a kind of chemical bond obtained from a vast amount of valence electrons that move freely across the metal lattice in the electron conduction band. While metal substitutes may include metal components, they are “nonmetals” in some respects. They are neither pure free metals nor alloys of free metals. When the metal is in its metal form, the electron conduction band tends to provide high reflectivity as well as high electrical conductivity for optical radiation, among other metal properties.

It is preferable that a 1st electrode is substantially transparent with respect to incident light (for example, (lambda)-800 nm). The first electrode may comprise, for example, indium tin oxide (ITO) or degenerately doped ITO. Other materials suitable for this purpose include, but are not limited to, for example, ZnO, TiO 2, Ag (silver), Au (gold) and Pt (platinum).

It is preferable that the second electrode substantially reflects incident light (for example, λ to 800 nm). The reflective electrode may be formed of a metal film such as Al (aluminum), Ag (silver), or Au (gold), In, Mg, Mg: Ag (-1: 10 ratio), Ca, or 0.5 nm LiF / 100 nm Al laminated film. It may include.

The term organic layer or "layer" as used herein refers to a photoconductive organic semiconductor material. As used herein, the term "semiconductor" refers to a material capable of conducting electricity when charge carriers are caused by heat or electromagnetic excitation. The term "photoconductivity" is generally associated with a process in which electromagnetic radiation is absorbed and converted into excitation energy of an electrical charge carrier so that the carrier can conduct, ie transport, electrical charge in the material. The terms "photoconductor" and "photoconductive material" are used herein to mean semiconductor materials that are selected for their property of absorbing electromagnetic radiation of selected spectral energy to produce electrical charge carriers.

The photosensitive device of the present invention comprises an electron transport layer formed of a first photoconductive organic [film] semiconductor material adjacent to the LHC and disposed between the first electrode and the LHC; And / or a hole transport layer formed of a second photoconductive organic semiconductor material adjacent the LHC and disposed between the second electrode and the LHC.

The electron transport layer may be formed of a photoconductive organic semiconductor, for example 3,4,9, lO-perylenetetracarboxylic-bis-benzimidazole (PTCBI). Other materials that have a general ability to extract electrons for this purpose and / or have a high affinity for electrons are for example BCP, AIq ₃ , CBP, Fi ₆ CuPc, C ₆₀ , PTCBI, and PTCDA. Including but not limited to.

The hole transport layer may be formed of a second photoconductive organic semiconductor, for example copper phthalocyanine (CuPc). Other materials having the general ability to donate electrons and / or low ionization potentials for this purpose include, but are not limited to, for example, αNPD.TPD, CuPc, CoPc, and ZnPc.

One or more additional photoconductive organic semiconductor material layers (up to about five layers) may be positioned between the first electrode and the electron transport layer in the solid state photosensitive device of the present invention. Similarly, one or more additional photoconductive organic semiconductor material layers (up to about five layers) may be located between the second electrode and the hole transport layer. The functions of these layers include, but are not limited to, spacer layers (for optical interference optimization), blocking layers, and multiplication layers.

In embodiments of the solid state photosensitive device described herein, it is preferred that the distance between the LHC and each electrode is about λ / 4n, where n is the refractive index of the material between the LHC and each electrode (n is generally As ~ 1.7)

Another embodiment of the solid state photosensitive device of the present invention is an exciton blocking of a photoconductive organic semiconductor material disposed between a second electrode and a hole transport layer, with a hole transport layer adjacent to the LHC and disposed between the second electrode and the LHC. Layer. Exemplary exciton blocking layer materials include 2,9-dimethyl-4,7-diphenyl-l, 10-phenanthroline (BCP); 4,4 ', 4 "-tris {N,-(3-methylphenyl) -N-phenylamino} triphenylamine (m-MTDATA); and polyethylene dioxythiophene (PEDOT); Forrest, et at., US Patent No. 6,451,415, entitled Organic Photosensitive Optoelectronic with an Exciton Blocking Layer ].

Another embodiment of the photosensitive device in the solid state is intended for the first electrode to have an aperture that allows light to the LHC. The solid state photosensitive device of the present invention may use an optical collector which allows light to LHC. Structures designed to capture light therein may generally be referred to as waveguide structures, or optical cavities, or reflective cavities. Since very thin photoactive layers can be used without sacrificing conversion efficiency, optical recycling possible within such optical cavities or waveguide structures is particularly advantageous in devices using organic photosensitive materials. Allowed light is collected and recycled through the contained photosensitive material to maximize light absorption. The purpose of this feature is to provide a highly efficient light conversion structure for increasing the collection of light and for capturing incident light and converting it into electrical energy. It is also an object of the present invention to provide a highly efficient light conversion structure that generally uses a conical dish type light collector. In addition, an object of the present invention is to provide a high-efficiency light conversion structure that generally uses a through-type dish-shaped light collector. It is also an object of the present invention to provide a highly efficient light conversion structure having an array of internal and external surfaces of a concentrator and a series of optical collectors and waveguide structures that concentrate and then recycle the captured radiation. Forrest, et ah, US Patent No. 6,333,458, called Highly Efficient Multiple Reflection Photosensitive Optoelectronic Device With Optical See Concentrator ].

As used herein, the term circuit has its general meaning, thereby referring to any circuit including a capacitor and a circuit including a load or an external load. The circuit may be applied with an external voltage. The photovoltaic device of the invention has the property of generating a photogenerated voltage and / or photocurrent when it is connected across a load and irradiated by light. 4 and 5 illustrate the production of a photocurrent, for example by a photosensitive device in a solid state, according to one embodiment of the invention.

The solid state photosensitive device of the present invention converts light into electricity. The apparatus of the present invention includes, for example, optical components, switches, sensors, logic gates and energy sources. Solid state photovoltaic (PV) devices are particularly provided for generating power. These devices are used to drive power consuming loads. Electronic facilities such as computers or remote monitoring or communication facilities can be operated by the solid state photosensitive device of the present invention. For example, many applications of nanoscale circuits will require distributed power supplies and photodetectors. The small size of the molecular complexes makes them ideal for functionality, design and purpose based on these materials. Such power generation applications may further include an energy storage device to enable or continue operation when direct lighting from the sun or other ambient light sources is unavailable. Solid state photosensitive devices, or devices incorporating the photosensitive devices of the present invention, include light powered molecular circuitry, solar cells, optical computing and logic gates, photoelectric switches, light, chemicals, toxins, pests. And electronic light sensors for sensing therapeutic agents, such as, but not limited to, photon A / D converters. The photosensitive device of the present invention can be used as a local energy source for nanoscale systems, eg, processing elements. The photovoltaic cell of the present invention may be, for example, about 10 ran in diameter.

The photosensitive device of the present invention may be incorporated into sensor devices for the detection of conditions, drugs, and / or organisms such as bacteria and viruses. Photosynthetic complexes can be compatible with biological and chemical systems, and photovoltaic energy sources can function in sensing applications. For example, sensors can use biological or chemical methods designed or evolved to sensitively detect biological and chemical agents. The response can be a change in current, voltage, capacitance, inductance, light output, for example, or absorbance. The presence of the analyte (component to be detected) turns on or off the photoreaction or changes the absorption or emission spectrum. Natural connections between these sensors and structures of complexes such as photosynthetic complexes have been developed in this way.

The expansion of molecular sensors based on LHC to molecular switches is shown in FIG. 6. Molecular sensors and structures of logic soda based on LHC. In both cases, energy is provided optically. This structure forms the basis of a wireless computer, where signals are performed by molecular triggers. In logic operation, the output of a single LHC unit must be input to another LHC. This requires that either of the photosynthetic units be used to generate a molecular trigger or that the LHC must be quenched by an electrical signal. LHC is used to generate molecular triggers that pass from one photosynthetic unit to the next, forming the basis of "wireless" computing.

Example

When metal contacts are deposited onto the light collecting complex (LHC), care must be taken not to inhibit the protein scaffold of the LHC. For this purpose, for example, nondestructive nanometric metal contact stamping techniques are used. Protein based complexes are interfaced with conventional electronic components using nanopatterning techniques. See, eg, Kim, et al, US Patent No. 6,468,819, Method For Patterning Organic Thin Film Devices Using A Die ; And, Lee, et al ., Programmable nanometer - Scdale Electrolytic Metal Deposition And Depletion , US Patent No. 6,447,663, each of which is incorporated herein by reference.

Example  I

The device can be assembled from one side. For example, the electrode can first be deposited on a substrate (eg glass or plastic). The PSI composite can be deposited, for example, on a transparent indium tin oxide electrode. Metallic contacts, PSI complexes, to LHC can be transferred directly to, for example, ultra high resolution intact stamping processes. The formation of metal contacts is compatible with the fragile protein (LHC) complex. The goal of this technique is to move the metal film at the point of contact between the lithographically patterned stamp and the substrate at a resolution comparable to the diameter (10 nm) of the PSI composite. If the substrate-metal adhesion surpasses the adhesion between the stamp and the metal layer, movement occurs. It can be deposited in between in order to improve the movement, at least one adhesion reducing layer, such as a Teflon ^® stamp surface and the metal layer (see Fig. 7 (Fig. 7-9)). Prior to step 1, a thin metal film (<50?) Is deposited on the substrate using vacuum deposition or sputtering. This "strike" layer is thin enough to minimize damage to any delicate features of the substrate. In step 1, the metal coated stamp is contacted with the strike layer. The metal is moved at the point of contact. Migration can be improved by inserting an adhesion reducing layer between the stamp and its metal coating, and possibly by removing the strike layer. After removal of the stamp in step 2, the patterned substrate is etched in step 3 and any exposed strike material is removed by Ar sputtering. 6,468,819, Method For Patterning Organic Thin Film Devices Using A Di e; and, Lee, et ai, Programmable Nanometer - Scdale Electrolytic Metal Deposition And Depletion , US Patent No. 6,447,663 ].

Although metal deposition is basically the first step in this embodiment, the (electrode) metal deposition of the electrode may be the final step of the construction process. As used herein, the term "electrode" encompasses "first electrode" or "second electrode" as used in the claims appended hereto.

Example II

The electrode can be patterned, for example lithography. However, patterning may occur simultaneously with electrode deposition as in I. 3 shows a schematic diagram of a number of LHC composites sandwiched between silver and transparent indium tin oxide (photoelectric device). Electron beam lithography can be used to pattern the TIO by exposing a self assembled LHC monolayer, thereby changing the surface adhesion properties of the LHC composite. The dimensions of the stamped contacts are defined by electron beam lithography. Electron beam lithography defining embossed features in stamps is known to those skilled in the art. It involves exposing the resist (polymer, generally PMMA-polymethyl methacrylate) to a fine (~ lnm) electron beam. When the resist is exposed, it will dissolve in a weak solvent leaving the unexposed portion intact. The resist pattern is then transferred to the stamp material by wet or dry etching techniques.

Example III

One to five organic layers can be added, for example, on top of the electrode, for example by thermal evaporation. LHC can be sandwiched between thin film organic charge transport materials. Since LHC requires a solution process, the supporting organic layer adjacent to the LHC may be a hydrophobic charge transport polymer (eg PPV (poly- (phenylene vinylene)) or PEDOT: PSS (polyethylene dioxythiophene: polystyrene-sulfo). Nate)). Overlayers adjacent to the LHC can be prepared from vacuum deposited small molecule materials to eliminate solvent collisions with the underlying polymer and the LHC. It is preferable that an organic layer is transparent with respect to incident light. Thus, the photoelectric action of heterostructures on visible light in the absence of LHC is negligible. Individual active optical molecules are contacted using, for example, organic thin films. Organic films of one to many (eg 5) molecular layers can be deposited using vacuum techniques, for example [SR Forrest, Chem . Rev. vol. 97, p. 1793 (1997).

Example IV

One or more LHCs, such as PSI or LH2, are deposited on the upper organic layer.

The system for controlling the electrodeposition of the deposit (eg, light collecting composite) preferably includes two electrodes in an overlapping relationship. Having inductive polarity, weak polarity or nonpolarity under electrodeposition conditions can covalently bind to a suitable charged carrier to form a charged complex that can be deposited on the electrode. Suspensions or solutions of deposition entities can be aqueous solutions, for example physiological saline, and can conduct significant currents. In the original deposition solution or suspension, the direction, movement speed and deposition rate can be very sensitively controlled by appropriately adjusting the pH of the solution. The pH of the solution or suspension is adjusted to be greater or less than the isoelectric point of the deposit being deposited. Such control can be achieved using any known known powder or alkali agent. In addition, other additives such as nonionic surfactants and antifoams or detergents may be added to the solution as desired. The electrode can be formed, for example, of a metal or “metal substitute” attached to a substrate. The substrate may be organic or inorganic, biological or abiotic, or any combination of these materials. Suitable materials as substrates include silicon, silica, quartz, glass, controlled pore glass, carbon, alumina, titanium dioxide, germanium, silicon nitride, zeolites and gallium arsenide. The term "metal" is an elementally pure metal, eg, a material comprising Ag or Mg, and a metal comprising two or more elementally pure metals, such as Mg and Ag (denoted Mg: Ag). It is also used to include all alloys. Herein, "metal substitutes" refer to materials which are not metals within the normal definition but which have the same properties as the desired metals in certain suitable applications. Suitable metal substitutes that can be used in the electrode include doped wide bandgap semiconductors, for example transparent conductive oxides such as indium tin oxide (ITO), gallium indium tin oxide (GITO), and zinc indium tin oxide (ZITO). . Other suitable materials as electrodes are polymeric metals such as polyethylene-dioxythiophene (PEDOT) doped with poly-styrenesulfonate (PSS). A power supply having a positive lead connected to one of the electrodes and a negative lead connected to the other electrode is provided to supply a substantially constant flow of current between the electrodes. The distance Di between the electrodes can range from about IO nm to about 5.0 mm. If the remaining area of the substrate is insulated, deposition on the nanoscale electrode can occur. An appropriate distance Di is about 1.0 mm. The voltage applied to the electrode depends on the distance Di. For example, the applied voltage can range from about 1 V / cm to about 1,000 V / cm. Appropriate voltage ranges from about 10 V / cm to about 200 V / cm can be used with distances between electrodes about 1 mm. A solution or suspension of deposits is provided between the electrodes. A voltage is continuously applied for a predetermined time to move the deposit toward one of the electrodes to provide deposition of the deposit film. For example, the voltage can be applied continuously for about 5 minutes to about 48 hours. The applied voltage is based on the desired thickness of the deposit film and the concentration of the solution to which the deposit is electrodeposited. It has been found that it is desirable to use the minimum distance between the electrodes to reduce the required voltage. The deposit concentration in the solution or suspension of the deposit and the volume of the solution are selected to control the thickness of the deposited film deposited by continuous application of a predetermined voltage. The concentration of deposits in solution or suspension can be selected to form a monolayer on one of the electrodes. In one embodiment of the invention, the concentration of deposits in the range of about lOμg / ml to about Img / ml, the volume of about lmm ³ to about 100mm ³ , the voltage in the range of about 10 V / cm to about 200 V / cm 100% of the deposit can be deposited on the electrode to obtain a single layer film having a thickness of about 5 nm to about IOnm. It will be appreciated that thicker membranes can be deposited by varying the concentration of deposits in the solution or suspension and the volume of the solution. The housing of the retainer may be sized to provide a predetermined volume of solution or suspension of the deposit. For example, the retainer housing may be sized to provide a volume of about lmm ³ to about 100 mm ³ . The movement of the deposit occurs towards the charged electrode in the opposite direction of the charge of the deposit. Deposits can be attached to the electrodes mostly due to van der Waals interactions between the deposits and the electrodes. A fixed deposit may be used in any device for which the fixed deposit is essential to the operation of the device. Suitable devices include solid state devices, memory devices and optoelectronic devices.

Monolayers of LHC can be deposited using conventional spinning techniques, for example in aqueous solution.

Light stimulation produces holes on the lower (lumen) surface of the LHC and electrons on the upper (stromal) surface, so the functional orientation of the LHC is important. Thus, when deposited on a substrate, it must be present in the proper orientation (depending on the intended application). Since both sides will have different charge densities or completely different charge polarities, this can be achieved by electrostatic deposition. Another possibility is the covalent binding or affinity for specific groups on the protein (these groups exist naturally or are inserted by recombinant DNA techniques). US Pat. No. 6,231,983, Method of Orienting Molecular Electronic Components, Lee, et al., May 15, 2001, for example, relates to a method of orienting a PSI reaction center on a substrate. The method includes chemical modification of the surface of the substrate such that the surface of the substrate can fix the PSI reaction center in a preselected orientation. Then, a solution containing the PSI reaction center is added and the PSI is oriented in a predetermined orientation. The predetermined orientation may be parallel to the surface of the substrate, perpendicular to the surface in the "up" position, or perpendicular to the surface in the "down" position. The determination of the predetermined orientation should be based on the desired use of the substrate.

Example  V

The organic layer can be added by thermal steam, for example, on top of the deposited light collecting composite, as in III.

Example VI

The upper electrode can be added by a nanometa stamping process, for example as in I.

All publications and patents mentioned in the above detailed description are incorporated herein by reference. Various modifications and variations of the compositions and methods of the invention described above may be apparent to those skilled in the art without departing from the scope and spirit of the invention. While the present invention has been described in connection with certain preferred embodiments, it should be understood that the claimed invention should not be unduly limited to such specific embodiments. Indeed, various modifications of the above-described compositions and modes for carrying out the invention are intended to be apparent to those skilled in the art or in the related art and are within the scope of the following claims.

Brief description of the drawings

1 shows one embodiment of a solid state photosensitive device of the present invention.

2 shows another solid state photosensitive device of the present invention.

3A shows a schematic embodiment of the invention.

3B shows a schematic diagram of a number of LHC composites sandwiched between silver and transparent indium tin oxide (photoelectric device).

4 shows the generation of a photocurrent by a solid state photosensitive device according to one embodiment of the invention.

5 shows the generation of a photocurrent by a solid state photosensitive device according to another embodiment of the invention.

6 shows an extension of a molecular sensor based on LHC to a molecular switch.

FIG. 7 illustrates one embodiment of a direct ultra high resolution, non-damaging stamping process for moving metal contacts to LHC.

8 shows the steps of an ultra high resolution, intact stamping process that moves metal contacts directly to LHC.

9 shows yet another step of an ultra high resolution, intact stamping process that moves metal contacts directly to LHC.

Claims (29)

A first electrode and a second electrode in an overlapping relationship; And A photosensitive device in a solid state comprising at least one insulated light collecting composite (LHC) between the electrodes. The method of claim 1, An electron transport layer disposed between the first electrode and the LHC and adjacent to the LHC and formed of the first photoconductive organic semiconductor material; And A hole transport layer disposed between the second electrode and the LHC and adjacent to the LHC and formed of a second photoconductive organic semiconductor material Solid state photosensitive device further comprising. The method of claim 2, And further comprising at least one additional layer of photoconductive organic semiconductor material disposed between the first electrode and the electron transport layer. The method of claim 2, And at least one additional layer of photoconductive organic semiconductor material disposed between the second electrode and the hole transport layer. The method of claim 3, And at least one additional layer of photoconductive organic semiconductor material disposed between the second electrode and the hole transport layer. The method of claim 4, wherein The photosensitive device in the solid state, wherein the photoconductive organic semiconductor material layer disposed between the second electrode and the hole transport layer is an exciton blocking layer. The method of claim 2, And the first electrode has an aperture that allows light to LHC. The method of claim 3, At least one additional photoconductive organic semiconductor material layer has an opening to allow light to the LHC. The method according to claim 7 or 8, A solid state photosensitive device further comprising an optical concentrator that allows light to LHC. The method of claim 1, And the first electrode is substantially transparent to incident light (λ to 800 nm). The method of claim 1, And the second electrode substantially reflects incident light (λ to 800 nm). The method of claim 5, Wherein the photoconductive organic semiconductor material between the electrodes is substantially transparent to incident light (λ-800 nm). The method of claim 10, And said first electrode comprises degenerately doped ITO. The method of claim 11, Wherein said second electrode comprises a metal film such as Al (aluminum), Ag (silver), or Au (gold). The method of claim 2, Wherein said electron transport layer comprises a material selected from the group consisting of PTCBI, BCP, AIq ₃ , CBP, Fi ₆ CuPc, C ₆₀ , and PTCDA. The method of claim 2, Wherein said hole transport layer comprises a material selected from the group consisting of αNPD, TPD, CuPc, CoPc, and ZnPc. The method of claim 3, The at least one layer of photoconductive organic semiconductor material disposed between the first electrode and the electron transport layer comprises a material selected from the group consisting of PTCBI, BCP, AIq ₃ , CBP, F ₁₆ CuPc, C ₆₀ , and PTCDA. Photosensitive device in state. The method of claim 4, wherein At least one layer of photoconductive organic semiconductor material disposed between the second electrode and the hole transport layer comprises a material selected from the group consisting of oNPD.TPD, CuPc, CoPc, and ZnPc. The method of claim 6, The exciton blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP); 4,4 ', 4 "-tris {N,-(3-methylphenyl) -N-phenylamino} triphenylamine (m-MTDATA); and polyethylene dioxythiophene (PEDOT) Photosensitive device in the solid state. The method of claim 1, The light converging composite (LHC) is selected from the group consisting of PSI and LH2 solid state photosensitive device. The method according to claim 2 or 5, The distance between the LHC and each electrode is about λ / 4n, where λ is the main wavelength of light absorbed by the LHC and n is the refractive index of the material between the LHC and each electrode. The method of claim 1, And said first electrode is further connected with said second electrode by a circuit. 23. The photosensitive device of claim 22, wherein the photosensitive device is a photovoltaic device. The method of claim 1, A solid state photosensitive device comprising a light collecting composite (LHC) monolayer. The method of claim 1, A solid state photosensitive device comprising one light collecting composite (LHC). A method of generating a photocurrent, comprising exposing the photovoltaic device of claim 23 to light. A method for powering a circuit comprising exposing the photovoltaic device of claim 23 to light. An electronic device comprising the photosensitive device in solid state according to claim 22. An electronic device comprising the solid state photosensitive device according to claim 28 selected from the group consisting of solar cells, optical computing and logic gates, optoelectronic switches, processing elements, electronic light sensors, sensors, and photon A / D converters.

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