CN101120458A - Solid-state photosensitive devices employing independent photosynthetic complexes - Google Patents

Abstract

Solid state photosensitive devices, including photovoltaic devices, are provided which include first and second electrodes in laminated relationship and at least one isolated LHC between the two electrodes. A preferred photosensitive device comprises: an electron transport layer formed of a first photoconductive organic semiconductor material adjacent to the LHC between the first electrode and the LHC; a hole transport layer formed of a second photoconductive organic semiconductor material layer, which is adjacent to the LHC and is located between this second electrode and the LHC. The solid state photosensitive device of the present invention may comprise at least one further layer of photoconductive organic semiconductor material between the first electrode and the electron transport layer and at least one further layer of photoconductive organic semiconductor material between the second electrode and the hole transport layer . Also provided are methods comprising exposing a photovoltage device of the invention to illumination to generate a photocurrent, as are electronic devices comprising the solid state photosensitive device of the invention.

Description

Solid-state photosensitive devices employing independent photosynthetic complexes

technical field

The present invention generally relates to solid-state photosensitive devices, including photovoltaic devices, comprising a first electrode and a second electrode in superimposed relationship, at least one independent photosynthetic complex (light-harvesting complex ( LHC) such as PSI (Photosystem I, eg from Spinach)) and/or LH2 (Light Harvesting Complex 2, from the order Caudobacteriaceae) between these two electrodes. Methods of powering circuits including illuminating an exposed photovoltage device of the invention are described, as are electronic devices incorporating the solid state photosensitive device of the invention.

Background technique

Photosynthesis is a biological process that converts electromagnetic energy into electrochemical energy through the reaction of light and dark. Photosynthesis occurs in specialized organelles called chlorophyll in green algae and higher plants. This chlorophyll is surrounded by a double membrane and contains thylakoids, which consist of superimposed membrane discs (called pigments) and non-superimposed membrane discs (matrix). This thylakoid membrane contains two key photosynthetic components, namely, photosynthetic system I and photosynthetic body II, denoted as PSI and PSII, respectively.

The pioneers in the electrical research of photosynthetic complexes are: Lee and Greenbaum at Oak Ridge National Lob. 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 deposited Pt onto electron-donating sites on the surface of the complex, and then treated the complex with platinum to generate _H2 . They also measured the orientation statistics of the complexes on the hydrophilic substrate while observing the photovoltage using a Kelvin force microscope. 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. See, also, United Stated Patent No. 6,162,278, entitled photobiomolecular Deposition of Met allic Particles and Films, Hu, December 19, 2000.

The fabrication of molecular circuits is currently beyond the resolution capabilities of conventional patterning techniques such as electron beam lithography. But positioning molecules with subnanometer precision is essentially routine and critical to the control of photosynthetic complexes. Photosynthetic complexes, for example, are optimized to concentrate energy from molecular antennae to reaction centers that generate charge. Native protein scaffolds control the precise positioning and orientation of optically and electronically active molecular components. Photosynthetic complexes have both size and functionality optimized through evolution. In a typical complex such as Synechococcus sp. Elongtus seen in the order Rhodobacteria, absorbed photons are captured and summed within 100 ps of photon absorption with a total quantum yield of 98%. A photovoltage of 1 volt was generated across the entire complex with a power conversion efficiency of about 40%. Schubert, W.D., et al, J. Moi. Biol. 272, 741-768 (1997). In fact, natural biomolecular complexes exceed the efficiency of even the best artificial optoelectronic devices.

But the prior art fails to describe efficient photoconversion structures for trapping incident light and converting it into electrical energy suitable for use in nanoelectronic devices. There remains a need in the art for solid-state photosensitive devices that enable photosynthetic protein-based molecular components to be associated with conventional electronic devices, including photovoltaic devices that convert light into photocurrent to power circuits.

Contents of the invention

For this reason, the main object of the invention described here is the solid-state incorporation of LHCs into functional devices comprising the use of a single photosynthetic complex (nor has the prior art envisioned the incorporation of organic layers into in solid-state photosensitive devices at the LHC).

There is provided a solid state photosensitive device comprising a first electrode 2 and a second electrode 4 in stacked relationship, the photosensitive device further comprising a standing light harvesting complex (LHC) 6 between the two electrodes.

The provided photosensitive device also includes: an electron transport layer 8 formed by a first photoconductive organic semiconductor material, which is adjacent to the LHC6 and located between the first electrode 2 and the LCH6; a gap formed by a second photoconductive organic semiconductor material The hole transport layer 10, which is adjacent to the LHC6, is located between the second electrode 4 and the LHC6.

Other embodiments of the present invention include: at least one further layer of photoconductive organic semiconductor material located between the first electrode 2 and the electron transport layer 8; and/or at least one further layer of photoconductive organic semiconductor material 14 located between the second between the electrode 4 and the hole transport layer 10 .

Embodiments of the invention are provided in which the electron and/or exciton blocking layer 16 is arranged between the second electrode 4 and the hole transport layer 10 .

The solid-state photosensitive device of the present invention is preferably: wherein first electrode 2 is transparent to incident light (wavelength λ-800nm) basically, and the organic semiconductor material between electrode 2 and 4 is transparent to incident light basically , and wherein the second electrode 4 substantially reflects incident light.

In the embodiment of the invention provided, the distance between the LHC and the electrodes 18 is approximately λ/4n, where λ is the peak wavelength of light absorbed by the LHC and n is the distance between the LHC and the electrodes (2 or 4) The refractive index of the material in between.

This solid-state photosensitive device is also preferably in which the first electrode 2 is also connected to the second electrode 4 through the circuit 20 .

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

Electronic devices are provided which include at least one solid state photosensitive device of the present invention.

Description of drawings

Figure 1 illustrates a solid state photosensitive device of the present invention.

Figure 2 schematically illustrates another solid state photosensitive device of the present invention.

Figure 3A schematically illustrates an embodiment of the present invention.

Figure 3B is a schematic diagram of several composites (photovoltaic devices) of LHCs sandwiched between silver and transparent indium tin oxide.

Fig. 4 shows photocurrent generation by an example of a solid-state photosensitive device of the present invention.

Fig. 5 illustrates another example of photocurrent generation by a solid state photosensitive device of the present invention.

Figure 6 shows the generalization of LHC-based molecular sensors to molecular switches.

Figure 7 shows an implementation of the direct transfer of metal contacts onto the LHC by an ultra-high resolution damage-free embossing process.

Figure 8 illustrates the transfer of metal contacts onto the LHC by a step in the ultra-high resolution damage-free embossing process.

Figure 9 illustrates the transfer of metal contacts onto the LHC by another step in the ultra-high resolution damage-free embossing process.

Detailed ways

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art of the invention. The contents of all publications and patents provided herein are incorporated herein by reference.

A general object of the present invention is to provide efficient light conversion structures for capturing incident light and converting it into electrical energy. In particular, the present invention relates to a solid state photosensitive device comprising a first electrode and a second electrode in superimposed relationship and at least one isolated UHC between the two electrodes. The photosensitive device of the present invention includes a photovoltage device that converts light into a photocurrent, thereby supplying electrical power to a circuit. The present invention is capable of a wide variety of embodiments that correlate protein-based molecular components of photosynthesis with conventional electronic devices. The invention is especially suitable for nanoscale photosensitive devices, including sensors, photocells and devices related thereto. The main objective of the present invention is to combine LHCs into functional devices including devices employing individual photosynthetic complexes. Nanoscale photodetectors and photocells for nanodevices are provided.

Referring to FIG. 1 , the solid-state photosensitive device of the present invention specifically includes a first electrode 2 and a second electrode 4 in a laminated relationship and at least one standing LHC 6 between the two electrodes. Embodiments of the present invention may also include, for example: an electron transport layer 8 formed of a first photoconductive organic semiconductor material, which is adjacent to the LHC6 and located between the first electrode 2 and the LHC6; formed of a second photoconductive organic semiconductor material The hole transport layer 10 is adjacent to the LHC6 and located between the second electrode 4 and the LHC6. Other embodiments of the present invention include: at least another layer of photoconductive organic semiconductor material 12, which is located between the first electrode 2 and the electron transport layer 8; and/or at least another layer of photoconductive organic semiconductor material 14, which is located at the first Between the second electrode 4 and the hole transport layer 10 .

Referring to FIG. 2 , an embodiment of the present invention is provided, wherein the exciton blocking layer 16 is disposed between the second electrode 4 and the hole transport layer 10 . The solid-state photosensitive device of the present invention is preferably: wherein first electrode 1 is substantially transparent to incident light (wavelength λ-800nm), the photoconductive organic semiconductor material between electrodes is substantially transparent to incident light, and wherein this first The two electrodes 4 substantially reflect incident light. In the embodiment of the invention provided, the distance 18 between the LHC and the electrodes is about λ/4n, where λ is the peak wavelength of light absorbed by the LHC and n is the refraction of the material between the LHC and the electrodes Rate. In the solid-state photosensitive device, the first electrode 2 is preferably connected to the second electrode 4 through the circuit 20 .

In particular, the progressive optimization process of the photosynthetic complex is utilized to provide efficient power conversion. The LHC localizes photosynthetic reagents with subnanometer precision in the solid-state photosensitive devices of the present invention and provides biomolecular electronic assembly for such devices. The precisely positioned molecules in the LHC components of the present invention interact through dipole-dipole coupling (analogous to antennas and receivers). This coupling is particularly sensitive to molecular position and orientation. The ultra-small size here reduces switching energy and transition time. The term "light-harvesting complex" (LHC) refers here to such photosynthetic complexes as PSI (Photosystem 1, e.g. from spinach), and/or LH2 (Light-harvesting complex 2, from Violales), Fromme , 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 PROTEINCABS Inc., 1425 Russ Blvd., Suit T-107C, San Diego, CA 92101. Photosynthetic system I (PSI), for example, is preferably HLC in the structure of the solid-state photosensitive device of the present invention, including the logic device. For example the PSI used in the present invention is preferably chlorophyll from eg spinach. PSI is a protein-chlorophyll complex with diodic properties that is part of the photosynthetic machinery within thylakoid membranes. It is oval in shape and about 5 x 6 nanometers in size. PSI is used here to create nanocircuits. This PSI reaction center/core antenna complex contains approximately 40 chlorophylls per photosensitive reaction center pigment (P700). Chlorophyll molecules act as antennas that absorb photons and transfer light energy to P700, where it is captured and used to drive photochemical reactions. In addition to P700 and antennal chlorophyll, this PSI complex contains many electron acceptors. The electrons released from P700 migrate through the intermediate acceptor at the reducing end of PSI to the terminal acceptor, and then the electrons are transported through the thylakoid membrane. The electrons migrate to the host surface of the PSI while the holes remain on the light emitting surface of the PSI. After photons are absorbed, this energy is directed to the primary electron donor at the base of the complex. After exciton dissociation, _electrons migrate to the opposite surface through the three _Fe4S4 clusters. As a result there are electrons on the upper (substrate) surface and holes on the lower (luminescent) surface. Therefore, due to the directionality of electron transport, such complexes preferably have the correct orientation when deposited on the surface. The work of Lee, et al. determined the selective deposition of PSI complexes on hydrophilic surfaces with the electron transfer vector perpendicular to the substrate-phys. Rev. Lett. 79, 3294-3297 (1997).

For the PSI reaction center, the midpoint oxidation potential energy generated by the primary electron donor (P700) is about +0.4v and the corresponding reduction potential energy generated by the electron acceptor (4Fe-4S center) is about -0.7v. The PSI reaction center is then a photodiode (unidirectional electron flow) and a nanoscale (about 6nm) solar cell.

Another important complex is the LHC, which is used by the Rhododendronaceae (acidophiles of the genus Rhodomonas) to absorb radiant solar energy. This LHC has been precipitated and crystallized Cogdel, R.J., et al., Biochimica et Biophysica Acta 722, 427-435 (1984); McDermott, G., et al., Nature 374, 517-521 (1995); Papiz, M.Z., et al., Journal of Molecular Biology 209, 833-835(1989); Fenna, R.E., et.al., Nature 258, 573-577(1975). The photosynthetic mechanism of the above-mentioned bacteria is optimized by biological methods, so that the energy can be concentrated to the reaction center within 100 ps and the total amount and yield are 98%. Sundstrom, V., et al., Journal of Physical Chemistry B103, 2327-2346 (1999); Renger, T., et al., Physics Beports 343, 137-254 (2001). This protein serves several purposes. It gives rigidity to the photosynthetic unit, holds pigments in place, and provides a heat sink for excess heat. Photosynthetic units have gradually evolved to resist degradation. For example, pigments called carotenoids can significantly increase the energy efficiency of photosynthetic units by quenching the triplet state (preventing the possible formation of singlet oxygen through triplet-triplet disappearance). stability. Photosynthetic complexes such as those described above can be used as components of the photodetectors and photocells described herein.

The biomolecular complex photosynthetic system I (PSI) known from Synechococcus sp. Elongtus of the order Fuchsiales is another example of an LHC for use in the solid-state photosensitive device of the present invention. Schubert, W. D. et al., J. MoI Biol. 272, 741-768 (1997). PSI preferentially forms trimer compounds. At the center of each PSI monomer, a charge is generated at the reaction center. There are about 100 chlorophyll molecules surrounding this reaction center. These molecules absorb light and direct it to this center, acting as an efficient antenna. There are also 15-25 carotenoid molecules that absorb light at wavelengths where chlorophyll molecules have low sensitivity, these carotenoids avoid structural oxidation by quenching the formation of singlet oxygen. PSI can exist alone or in combination with other LHCs, which enhances its absorption at low light levels.

Since LHC reaction centers are pigment-protein complexes that determine the photosynthetic conversion of light energy to electrical energy, such reaction centers are used as components of a variety of different devices as described herein.

The present invention provides such a solid state photosensitive device comprising at least one separate LHC electronically connected to a first electrode and independently electronically connected to a second electrode. Also provided is such a photovoltaic device comprising at least one isolated LHC electronically connected to a first electrode and electronically independently connected to a second electrode, and wherein the first electrode is also electrically connected to the second electrode via an electrical circuit. Electrode connection. The solid state photosensitive device of the present invention comprises a first electrode and a second electrode in superimposed relationship and at least one isolated LHC between the two electrodes. The present invention provides a system that uses light harvesting and charge separation methods for photosynthetic systems, but also as efficient light-to-current converters in molecular devices.

The electrodes or contacts used in the solid state photosensitive devices of the present invention are of particular concern. It is desirable to allow maximum transfer of ambient electromagnetic radiation from the exterior of the device to the photoconductive active interior region. That is, it is desirable to have electromagnetic radiation reach a point where it can be converted to electricity by photoconductive absorption. This generally means that at least one of these electrical contacts should least absorb and least reflect incident electromagnetic radiation. That is to say, such joints should be substantially transparent. The terms "electrodes" and "junctions" as used herein refer only to those layers which provide an intermediate means for delivering light-generating power to an external circuit or provide a bias voltage for such a device. That is, electrodes or contacts provide an interface between the photoconductive active region of a solid-state photosensitive device and a wire, lead, trace or other device for transporting or exporting charge carriers with respect to an external circuit. The term "charge transfer layer" here refers to a layer that is somewhat similar to an electrode, but differs in that the charge transfer layer only transports charge carriers from one subregion of the device to an adjacent subregion. A layer of organic material or a series of layers of different materials is referred to herein as "transparent" when such layers allow at least 50% of ambient electromagnetic radiation at the relevant wavelength to pass through such layers. Similarly, such layers are said to be "translucent" when they transmit less than 50% of ambient electromagnetic radiation at the relevant wavelength.

The electrodes or contacts are usually metallic or "metal substitute". The word "metal" herein is used to include pure metals in the sense of elements such as Mg and metal alloy materials composed of two or more pure metals in the sense of elements such as Mg and Ag together and denoted as Mg:Ag. As used herein, the term "metal substitute" refers to a material which is not a metal by definition, but which has desirable metal-like properties for some suitable applications. Typical metal substitutes for electrodes and charge transfer layers would include doped wide bandgap semiconductors such as transparent conducting oxides such as indium tin oxide (ITO), gallium indium tin oxide (GITO) and zinc indium tin oxide. In particular, ITO is a highly doped degenerate n ⁺ semiconductor with an optical band gap of about 3.2 eV, allowing it to transmit wavelengths greater than about 3900 angstroms. Another suitable metal substitute material is the transparent conductive polymer polyaniline (PANI) and its chemical relatives. Metal substitutes can also be selected from a wide range of non-metallic materials, wherein the term "non-metallic" is used to include a broad class of materials that are metal-free in their uncombined form. A metal may also be considered to be in its metallic form or "free metal" when it exists in its uncombined form either alone or in combination with one or more other metals as an alloy. ". Thus, the metal-replacement electrodes of the present invention may sometimes be referred to as "metal-free", with the term "metal-free" including materials that are metal-free in their uncombined form. Free metals usually have the form of metallic bonds that can be considered as chemical-like bonds that arise from a large number of valence electrons that are free to move along different electronic bands throughout the metal lattice. Although metal substitutes may contain metal components, they are "non-metallic" for several reasons. They are not pure free metals, nor are they alloys of free metals. Electronic conduction bands, among other metallic properties, also provide high electrical conductivity and high reflectivity for optical radiation when metals are present in their metallic form.

The first electrode is preferably substantially transparent to incident light (eg, wavelength λ-800nm). This first electrode may comprise, for example, indium tin oxide (ITO) or degenerately doped ITO. Other suitable materials include, but are not limited to, eg, ZnO, TiO ₂ , Ag, Au, and Pt.

The second electrode is preferably substantially reflective of incident light (eg, wavelength λ-800nm). Such a reflective electrode may comprise, for example, a film of the underlying metal: Al, Ag or Au, In, Mg, Mg:Ag (-1:10), Ca or a stack of 0.5nm LiF/100nm Al.

The term organic layer or layer as used herein refers to a photoconductive organic semiconductor material. The term "semiconductor" here refers to a material capable of conducting electricity when charge carriers are induced due to thermal or electromagnetic excitation. The aforementioned "photoconduction" generally refers to the following process: the energy of electromagnetic radiation is absorbed and converted into the excitation energy of carriers, so that the carriers can conduct, that is, transfer charges in the material. "Photoconductor" and "photoconductive material" are used herein to refer to semiconductor materials that have the property of absorbing electromagnetic radiation of selected spectral energies to generate charge carriers.

The photosensitive device of the present invention may also include: an electron transport layer formed of a first photoconductive organic (layer) semiconductor material, adjacent to the LHC, between the first electrode and the LHC, and/or formed of a second photoconductive organic A hole transfer layer formed of semiconductor material is adjacent to the LHC and located between the second electrode and the LHC.

The electron transport layer can be made of photoconductive organic semiconductor such as 3, 4, 9, 10 times tetracarboxybisbenzimidazole (PTCBI). Other generally electron-extracting and/or high-affinity materials suitable for this purpose include, but are not limited to, eg, BCP, _AIq3 , CBP, _Fi6CuPc , _C60 , PTCBI, and PTCDA.

The hole transport layer may be formed of a second photoconductive organic semiconductor such as copper phthalocyanine (CuPc). Other materials suitable for this purpose that are generally electron donating and/or have a low ionization potential include, but are not limited to, eg, αNPD.TPD, CuPc, CoPc, and ZnPc.

In the solid-state photosensitive device of the present invention, one or more layers (up to 5 layers) of photoconductive organic semiconductor materials are additionally provided between the first electrode and the electron transfer layer. Similarly, one or more layers (up to 5 layers) of photoconductive organic semiconductor material may be further provided between the second electrode and the hole transport layer. The functions of these layers include, but are not limited to, spacer layers (for optimizing light wave interference), barrier layers, and multiplication layers.

The solid-state photosensitive device described above is preferably implemented such 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 typically about ~1.7).

Other embodiments of the solid-state photosensitive device of the present invention include, in addition to the hole transport layer adjacent to the LHC between the second electrode and the LHC, a photoconductive organic layer positioned between the second electrode and the hole transport layer. Exciton blocking layers of semiconductor materials. Examples of exciton blocking layer materials include, but are not limited to, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP); 4,4′,4″-tris{N,- (3-methylphenyl)-N-anilino}triphenylamine (m-MTDATA); and polyethylenedioxythiophene (PEDOT). See, Forrest, et al., U.S. Patent No. 6,451,415, entitled "Having Organic Photosensitive Optoelectronic Devices with Exciton Blocking Layers".

Other embodiments of the solid-state photosensitive device described above are envisaged in which the first electrode has an aperture allowing light to enter the LHC. The solid-state photosensitive device of the present invention can utilize light concentrators to introduce light into the LHC. A structure designed to trap light therein may be generally referred to as a waveguide structure, or also as an optical or reflective cavity. The fact that light can be recycled repeatedly within such an optical cavity or waveguide structure is particularly beneficial for structures using organic photosensitive materials, since extremely thin photoactive layers can be used without sacrificing conversion efficiency. The incoming light is captured and recycled to maximize light absorption by the photosensitive material that contains it. The purpose of this feature is to increase the concentrated light while providing a highly efficient light conversion structure for capturing incident light and converting it into electrical energy, another purpose is to provide a highly efficient light conversion structure utilizing a generally conical parabolic concentrator . Yet another object is to provide a highly efficient light conversion structure utilizing substantially trough-shaped parabolic concentrators. Yet another object is to provide an efficient light conversion structure with a series of concentrators and waveguide structures, whereby the inner and outer surfaces of the concentrators are used to concentrate and then recycle the captured optical radiation. See Forrest et al, US Patent No. 6,333,458, entitled "Efficient Multiple Reflection Photosensitive Optoelectronic Devices with Light Concentrators."

The term circuit is used here in its ordinary sense and thus refers to any circuit including capacitors as well as circuits including loads or external loads. This circuit can be applied with an external voltage. The photovoltaic devices of the present invention have the property that when they are connected to a load and irradiated with light, they generate a photogenerated voltage and/or a photocurrent. Figures 4 and 5 illustrate photocurrent generation by an example of a solid state photosensitive device of the present invention.

The solid state photosensitive devices of the present invention convert light into electricity. The aforementioned devices of the present invention include, for example, optical components, switches, sensors, logic gates, and energy sources. In particular solid state photovoltaic (PV) devices are provided to generate electrical power. These devices are used to drive loads that consume power. Electronic equipment such as computers or remote control or communication equipment can be driven using the solid state photosensitive device of the present invention. Many applications of nanoscale circuits, for example, may require distributed power supplies and photodetectors. The small size of the aforementioned molecular complexes can ideally serve the purposes, design, and functional development of such materials. The application in this direction of power generation may also involve energy storage devices, which can be used in energy storage devices that cannot be powered by the sun or other environments. Allows work to continue while the light source is receiving direct illumination. Solid-state photosensitive devices incorporating photosensitive devices of the present invention include, but are not limited to, light-driven molecular circuitry; solar cells, optical computing and logic gates; optoelectronic switches; electronic devices that detect, for example, light, chemicals, toxins, pathogens and therapeutic agents. Light sensor and photon A/D converter. The photosensitive devices of the present invention can be used as local energy sources for nanoscale systems such as processing elements. Photovoltaic cells of the invention may be as small as 10 ran in diameter, for example.

The photosensitive devices of the present invention can be incorporated into sensor devices for detecting health conditions, pathogens and/or organisms such as bacteria and viruses. Photosynthetic complexes can be integrated with biological and chemical systems, while photovoltaic energy sources can be used for sensing applications. Sensors may, for example, employ biological or chemical methods developed or designed to sensitively detect biological or chemical agents, the response of which may be, for example, a change in current, voltage, capacitance, inductance, light output, or may be a change in absorption. The presence of the analyte (substance to be detected) will switch on or off the photosensitive response or change the absorption or change the emission spectrum. The natural link between these sensors and the structure of complexes such as the photosynthetic complex is exploited in this way.

Figure 6 shows the extension of LHC-based molecular sensors to molecular switches, which involves the structure of LHC-based molecular sensors and logic elements. In both cases the energy is provided optically. This structure forms the basis of a wireless computer in which signals are carried by molecular trigger circuits. For logic operations, the output of one LHC unit should be the input of another LHC. This requires that the photosynthetic unit can be used to generate molecularly triggered circuits or that the LHC must be quenched by electrical signals. The LHC is used to generate molecular trigger circuits that pass from one photosynthetic unit to the next, forming the basis for "wireless" computing.

example

Care should be taken not to disturb the protein scaffold of the LHC when setting the metal contacts onto the LHC. For this purpose, the non-destructive nanometal contact profiling technique is used, for example. This protein-based complex is made from conventional electronic components using nanopatterning techniques. See, for example: Kim, et al, U.S. 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, U.S. Patent No. 6,447,663 each The contents of the literature are incorporated herein by reference.

example 1

The device is formed ("grown") from one side. For example electrodes may first be deposited on a substrate (eg glass or plastic). The PSI composite can, for example, be deposited on a transparent indium tin oxide electrode. Metallic contacts of a PSI composite to the LHC can be directly transferred, for example, by ultra-high resolution damage-free embossing. The formed metal junction must be compatible with the fragile protein (LHC) complex. The above-described technique aims to transfer a metal film at the contact point between the photolithographically patterned stamp and the substrate with a resolution equivalent to the diameter of the PSI composite (approximately 10 nm). Transfer can occur as long as the substrate-to-metal adhesion exceeds the adhesion of the die to the metal layer. To improve transfer, one or more adhesion-weakening layers such as Teflon can be placed between the profiled surface and the metal layer, see FIG. 7 (FIGS. 7-9). Before step 1, a thin layer (<50) of metal is deposited by vacuum evaporation or sputtering. This "bump" layer is thin enough to minimize damage to any fine features of the substrate. In step 1, a metal-coated profile is brought into contact with this touch-up layer, and the metal is transferred at these contact points. By inserting an adhesion-weakening layer between the profile and its metal coating the transfer efficiency can be increased and a touch-up layer can be dispensed with. After removing the pattern in step 2, the patterned substrate is etched in step 3 while Ar sputtering is used to remove any exposed contact material. See: U.S. Patent No. 6,468,819, Method For Patterning Organic Thin Film Devices Using A Die; and, Lee, et ai, Programmable Nanometer-Scdale Electrolytic Metal Deposition And Depletion, U.S. Patent No. 6,477,663. Although in this example basically the metal-deposited electrodes are used as the first step (electrodes), it is also possible to metal-deposit the electrodes as the last step in this construction method. The term "electrode" is used herein as a generic term for "first electrode" or "second electrode", as in the appended claims.

Example II

The above-mentioned electrodes can be patterned, for example, by photolithography. But patterning can be done simultaneously with the electrode deposition step in Example I. Figure 3 schematically shows a composite (photovoltaic device) of several LHCs sandwiched between silver and a transparent indium tin oxide (TIO) film. This TIO can be patterned by e-beam lithography by exposing the self-assembled LHC monolayer, which modifies the adhesion properties of the LHC. The dimensions of the joints in the profiling form are determined by electron beam lithography. Determining the shape of the bumps on a die by electron beam lithography is well known, which involves exposing a resist (polymer, usually PMMA-polymethylmethacrylate) to a fine (~1 nm) under the electron beam. The exposed parts of the resist will dissolve under the weak solvent while leaving the unexposed parts intact. The resist pattern is then turned onto the stamp by wet or dry etching techniques.

Example III

On top of the electrodes, for example, 1-5 organic layers can be added by thermal evaporation. LHCs can be sandwiched between charge-transporting thin-film organic materials. Since the LHC requires solution processing, the supporting organic layer adjacent to the LHC is preferably a hydrophobic charge-transporting polymer (such as PPV (polyphenylene vinylene) or PEDOT:PSS (polyethylenedioxythiophene:polystyrene- Sulfonate)). The surface layer adjacent to the LHC can be fabricated by vacuum evaporating a small amount of molecular material to avoid solvent conflicts with the underlying polymer and LHC. The aforementioned organic layer is preferably transparent to incident light. Therefore, the photovoltage effect of this heterostructure on visible light is negligible in the absence of LHC. The individual active photomolecules are contacted, for example, with organic thin films. For example, one to more (for example five) molecular layers can be grown using vacuum techniques. S. R. Forrest, Chem. Rev. vol. 97, p 1793 (1997).

Example IV

At least one LHC such as PSI or LH2 is deposited on the uppermost organic layer.

Electrodeposition systems used to condition deposits such as LHC preferably include two electrodes in superimposed relationship. Substances with weak or non-existent or induced polarity under electrodeposition conditions can covalently link appropriate charge carriers to form charged complexes that can be deposited onto electrodes. Solutions or suspensions of deposits may be aqueous solutions such as physiological saline, capable of conducting significant electrical currents. The orientation, mobility and deposition rate of deposits initially in a deposit solution or suspension can be controlled with great sensitivity by properly adjusting the pH of the solution. The pH of the solution or suspension is adjusted to be above or below the isoelectric point of the deposit to be deposited. This adjustment can be accomplished using known acidic or basic reagents as desired. Other additives such as non-ionic surfactants and anti-foaming agents or detergents can also be added to this solution as required. The electrodes may be formed from metal or "metal substitutes" attached to the substrate. Substrates can be organic or inorganic, biotic or abiotic, or any combination of such materials. Suitable materials for substrates include silicon, silicon dioxide, quartz, glass, controlled porosity glass, carbon, alumina, carbon dioxide, germanium, silicon nitride, zeolites, and gallium arsenide. The term "metal" is used herein to include pure metals in the elemental sense, such as Ag or Mg, as well as metal alloy materials composed of two or more pure metals in the elemental sense, such as Mg and Ag, denoted Mg: Ag. As used herein, the term "metal substitute" refers to a material that is not a metal under the usual definition, but which has desirable metal-like properties for some appropriate applications. Suitable metal substitutes that can be used for the electrodes include doped wide bandgap semiconductors such as transparent conducting oxides such as indium tin oxide (ITO), gallium indium tin oxide (GITO) and zinc indium tin oxide (ZITO). Other suitable materials for electrodes are polystyrene sulfonate (PSS) doped polymeric metals such as polyethylenedioxythiophene (PEDOT). 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 provide a substantially constant current between the two electrodes, the distance Di between the two electrodes may be from about 10 nm to about 5.0 mm . Deposition on nanoscale electrodes is possible as long as the remaining area of the substrate is insulated. A suitable distance Di is about 1.0 mm. The voltage applied to the electrodes depends on this distance Di. For example, a voltage of about 1 v/cm to about 1000 v/cm can be applied. For a distance Di between the electrodes of about 1 mm, a suitable voltage is about 10 v/cm to about 200 v/cm. A solution or suspension of the deposit is provided between the two electrodes. The voltage is continuously applied for a predetermined time so that the deposited body can move toward an electrode to provide a deposited film of the deposit. For example, the voltage can be applied continuously for about 5 minutes to about 48 hours. The applied voltage depends on the desired film thickness of the deposit and the concentration of the solution used to electrodeposit the deposit. It has been found that it is best to minimize the distance between the two electrodes to reduce the required voltage. The concentration of the deposit in its solution or suspension and the volume of the solution are selected to control the film thickness of the deposit under continuous application of a predetermined voltage. The concentration of the deposit in solution or suspension can be selected to form a monolayer film on one of the electrodes. In one embodiment of the present invention, 100% of the deposit can be deposited on an electrode, at this time, the concentration of the deposit used is about 10 μg/ml to about 1 mg/ml, and the volume is about 1 mm ³ to about 100 mm ³ And the voltage is about 10v/cm to about 200v/cm, and the thickness of the formed single layer is about 5nm to about 10nm. It will be appreciated that thicker films can be deposited by varying the concentration of the deposit in solution or suspension and the volume of such solution. A holding tank of selected dimensions may be used to provide a predetermined volume of solution or suspension of the deposit. For example, the holding tank can provide a volume of about 1 mm ³ to about 100 mm ³ . The migration of the deposits towards the charged electrodes occurs in the opposite direction to the charge of the deposits. The deposit can adhere to the electrodes in large quantities due to its van der Waals interaction with the electrodes. The immobilized deposit can be used in any relevant device where the immobilized deposit is essential for the functioning of the device. Suitable devices include solid state devices, memory devices and photovoltaic devices.

Monolayers of LHC can be deposited, for example using the usual spin-coating technique in aqueous solution.

The functional orientation of the LHC is important because light stimulation generates electrons on the upper (substrate) surface and holes on the lower (cavity) surface of the LHC. Therefore, the LHC must be properly oriented when deposited on the substrate (this should depend on the specific application). This can be realized by electrostatic deposition technology, because the above-mentioned upper and lower sides will have different charge densities and even different charge polarities. Other possibilities are affinity or covalent bonding to specific groups on the protein (these groups can be naturally occurring or can be inserted by complex DNA techniques). For example, U.S. Patent No. 6231983 "Orientation method of molecular electronic components" (Lee et al., on May 15, 2001) is exactly the method for the orientation of PSI reaction center on the substrate. This method involves modifying the surface of the substrate to anchor the PSI reaction centers in a selected orientation. A solution containing the reaction centers of the PSI is then added, and the PSI is oriented in the chosen direction. The selected direction may be parallel to the substrate surface, perpendicular to the surface in the "upward" position or normal to the surface in the "downward" position. The choice of orientation should be based on the intended use of the substrate.

Example V

An organic layer can be added, for example, to the upper surface of the deposited LHC by thermal evaporation as described in Example III.

Example VI

The top electrode can be added using nano-stamping process such as in Example 1.

The contents of all publications and patents mentioned in the above specification are hereby incorporated by reference. Various modifications and variations of the composition and method of the present invention described above will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. Although the invention has been described in connection with specific preferred embodiments. However, it should be recognized that the present invention is not limited to these specific forms of implementation. In fact, the composition and mode described for implementing the present invention, and their various modifications are clear to those skilled in this technology or related fields, and should fall within the scope of the appended claims.

Claims (29)

1. solid state photosensor, it comprises:

Become first electrode and second electrode of stacked relation; And

The light capture complexes (LHC) that at least one arc between these two electrodes is upright.

2. according to the solid state photosensor of claim 1, it also comprises:

By the electron transfer layer that the first photoconductive organic semiconducting materials forms, it is adjacent with LHC, between this first electrode and LHC;

By the hole moving layer that the second photoconductive organic semiconducting materials forms, it is adjacent with LHC, between this second electrode and LHC.

3. according to the solid state photosensor of claim 2, it also comprises: the photoconduction of another layer at least electricity organic semiconducting materials between this first electrode and electron transfer layer.

4. according to the solid state photosensor of claim 2, it also comprises: the photoconduction of another layer at least electricity organic semiconducting materials between this second electrode and hole moving layer.

5. according to the solid state photosensor of claim 3, it also comprises: the photoconduction of another layer at least electricity organic semiconducting materials between this second electrode and hole moving layer.

6. according to the solid state photosensor of claim 4, wherein the photoconductive organic semiconducting materials layer between this second electrode and hole moving layer is an exciton barrier-layer.

7. according to the solid state photosensor of claim 2, wherein this first electrode has the hole that photoconduction can be guided to LHC.

8. according to the solid state photosensor of claim 3, wherein this at least the photoconductive organic semiconducting materials of another layer have the hole that photoconduction can be guided to LHC.

9. according to the solid state photosensor of claim 7 or 8, it also comprises and is used for photoconduction is drawn concentrator to LHC.

10. according to the solid-state photosensor of claim 1, wherein (wavelength X-800nm) is transparent to the first electrode pair incident light substantially.

11. according to the solid-state photosensor of claim 1, the second electrode pair incident light (wavelength X-800nm) reflect substantially wherein.

12. according to the solid-state photosensor of claim 5, wherein (wavelength X-800nm) is transparent substantially to incident light at two interelectrode photoconductive organic semiconducting materials.

13. according to the solid-state photosensor of claim 10, wherein this first electrode comprises the doped ITO of degeneracy.

14. according to the solid-state photosensor of claim 11, wherein this second electrode comprises for example metal film of Al, Ag or Au etc.

15. according to the solid-state photosensor of claim 2, wherein this electron transfer layer comprises and is selected from PTCBI, BCP, AIq ₃, CBP, Fi ₆CuPc, C ₆₀With the material in this group of PTCDA.

16. in the solid-state photosensor according to claim 2, wherein this hole moving layer comprises the material that is selected from this group of α NPD, TPD, CuPc, CoPc and ZnPc.

17. in the solid-state photosensor according to claim 3, wherein this one deck at least photoconduction organic semiconducting materials layer between first electrode and electron transfer layer comprises and is selected from PTCBI, BCP, AIq ₃, CBP, F ₁₆CuPc, C ₆₀With the material in this group of PTCDA.

18. in the solid-state photosensor according to claim 4, wherein this photoconduction of one deck at least organic semiconducting materials layer between second electrode and hole moving layer comprises the material that is selected from this group of oNPD.TPD, CuPc, CoPc and ZnPc.

19. according to the solid-state photosensor of claim 6, wherein this exciton barrier-layer comprises and is selected from 2,9-dimethyl-4,7-hexichol-1,10-phenanthroline (BCP); 4,4 ', 4 " three { N ,-(3-aminomethyl phenyl)-N-phenylamino } triphenylamines (m-MTDATA); And the material in the group of polyethylene dioxythiophene (PEDOT).

20. in the solid-state photosensor according to claim 1, wherein this light capture complexes (LHC) is selected from PSI and this group of LH2.

21., wherein be about λ/4n, and a kind of important optical wavelength that this λ is LHC to be absorbed and n is the refractive index of LHC and each interelectrode material at LHC and each interelectrode distance according to claim 2 or 5 described solid state photosensors.

22. according to the solid state photosensor of claim 1, wherein this first electrode also is connected to this second electrode by circuit.

23. according to the solid state photosensor of claim 22, wherein this solid state photosensor is a photovoltage device.

24. according to the solid state photosensor of claim 1, it also comprises the light capture complexes LHC of individual layer.

25. according to the solid state photosensor of claim 1, it also comprises single light capture complexes LHC.

26. a method that produces photoelectric current, the method comprise the photovoltage device exposure that makes claim 23 and throw light on.

27. a method of giving circuit supply, the method comprise the photovoltage device exposure that makes claim 23 and throw light on.

28. an electronic device, it comprises the solid state photosensor of claim 22.

29. according to the electronic device that comprises solid state photosensor of claim 28, and above-mentioned light-sensitive device is selected from this group of solar cell, photometry calculation and gate, optoelectronic switch, treatment element, electronic type optical sensor, transducer and photon A/D converter.

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