EP1442485A2 - Molecular electronic component used to construct nanoelectronic circuits, molecular electronic component, electronic circuit and method for producing the same - Google Patents

Abstract

The invention relates to a molecular electronic component used to construct nanoelectronic circuits. Said molecular electronic component comprises a redox-active unit with an electron donor (D) and an electron acceptor (A). The electron donor and the electron acceptor (A) comprise one point of contact (K1, K2) each for connection to other components and the points of contact (K1, K2) allow a charge carrier transfer to the component and away from the component. Especially, the point of contact (K1, K2) of electron donor (D) and electron acceptor (A) is a permanent point of contact for mediating charge carrier transport via a permanent chemical bond, said point of contact comprising one binding partner of the chemical bond each. A plurality of such components can be assembled via the points of contact to an assembly or to an electronic circuit.

Description

Molecular electronic component for the construction of nanoelectronic circuits, molecular electronic assembly, electronic circuit and manufacturing process

Technical field

The present invention relates to the field of components of molecular dimensions for the construction of nanoelectronic circuits, and relates in particular to a molecular electronic component, a molecular electronic assembly comprising molecular components and an electronic circuit with such molecular components or assemblies, as well as a production method for such an electronic circuit.

State of the art

The technological development of microelectronics is documented by the SIA (Semiconductor Industry Association) (SIA roadmap: www.sematech.org/public/publications). It predicts the fourfold increase in the complexity of electronic chips per three-year period (Moore's law) since 1970, also for the next two decades. Semiconductor technology will increasingly come up against physical limits, especially since the necessary structure sizes will soon assume molecular dimensions. Against this background, efforts are increasingly being made to implement electronic components with dimensions of a few nanometers - so-called nanoelectronic components.

A circuit arrangement is described in the patent specification DE 198 58 759 as to how nanoelectronic components can be combined with a CMOS component in a semiconductor substrate. However, the nanoelectronic components themselves are not dealt with in this document. Transistors are known as nanoelectronic components and consist of semiconductor structures with a size of a few nanometers. For example, in FG Picus et al. (Nanoscale field-effect transistors: An ultimate size analysis, Appl. Phys. Lett. 71 (25) (1997) 3661) describes a nanoelectronic CMOS component. These are miniaturized "classic" components based on semiconductor crystals and not components that are made up of individual molecules.

In US 4,539,507, US 5247190 and DE 197 35 653 polymers are presented as electroluminescent substances. Layers of active materials are discussed that can be used for the production of organic light-emitting diodes (OLEDs). Individual documents as separately contactable units are not described in these publications.

Since the discovery of fullerenes and the discovery of the superconductivity of n-doped fullerenes, there has been considerable research activity with these closed carbon molecules (C _n molecules with n> 60). Fullerenes can be grown as crystals or applied as epitaxial layers. These so-called fullerites are dealt with in DE 198 22 333 and can be doped in order to produce electronic components.

WO 98/39250 also discusses carbon nanotubes consisting of fullerenes with a diameter of 0.6 to 100 nm and a length of 5 to 1000 nm, which act as molecular electrical conductors for quantum effect components, but also as antennas for optical frequencies, STM and AFM Tips are suitable. A memory cell with a nanobit (1.38 nm diameter, 10-50 nm length) is described, which is written and read over equally small molecular "wires". The bit is stored due to the bistable position of a small molecule within a nanotube Carbon nanotubes also serve as molecular wires.

Molecular conductors are known in many embodiments. In S. Kagoshima et al. (One-dimensional conductors, Springer Verlag 1988), in addition to conductive organic crystals such as fluoranthene, perylene hexafluorophosphate and other radical cation salts of arenes, above all conductive linear polymers have been described. The latter include polyethylenes (CH) _X , carbyne C _x , sulfur-nitrogen polymers (SN) _X , polypyrroles and phenylazetylenes (= phenylethynyls). Oligo-phenylethynyls have been described by S. Creager et al. (J. Am. Chem. Soc. 121 (1999) 1059-1064) as molecular wires between gold electrodes and ferrocenes. JD Holmes (Science 287 (2000) 1471) describes nanowires from silicon crystals with diameters of 4 to 5 nm and lengths of a few micrometers.

P. Fromherz (Phys. Blätter 57 (2001) 43) refers to the electrical conductivity of nerve cells and describes their functional contact on semiconductor chips. The possibility of building hybrid networks of nerve cells and microelectronics is promised.

It is known from WO 00/31101 that double-stranded nucleic acid oligomers, in particular double-stranded DNA, can also function as a molecular electrical conductor.

The photosynthesis (RC) reaction center is another natural system in which currents flow at the molecular level. Based on the structural elucidation of RCs of the purple bacteria Rhodopseudomonas viridis (R. viridis) (J. Deisenhofer et al., Nature 318 (1985) 618) and Rhodobaoter sphaeroides (Rb.sphaeroides) (C. Chang et al., FEBS Letters 205 (1986) 82) the mechanism of charge separation was elucidated in detail. Both reaction centers consist of pigments (a bacteriochlorophyll dimer P, two bacteriochlorophylls B _A and B _B , two bacteriopheophytins H _A and H _B and two quinones Q and Q _B ), which are embedded in a protein matrix. In the RC, a photochemical reaction begins when light is irradiated, which results in an electron transfer and thus a transmembrane electrochemical potential gradient, which ultimately leads to the synthesis of high-energy substances. The photo-induced charge separation leads via an electron transfer chain from the excited state P * via B _A , H _A and Q to the final electron acceptor Q _B. After a two-fold reduction, it is protonated and releases as Q _B H ₂ from the protein pocket. An electron transfer chain follows over several cytochromes, which among other things reduces the primary electron donor P again. In the case of Q _B -free RCs, the state P ⁺ Q ^" , which is stable for 100 ms, is formed by the photo-induced charge separation within 200 ps with a quantum yield of 99.9%.

The reaction center of the thermophilic green bacterium Chloroflexus aurantiacus (Chl aurantiacus) is characterized by a temperature resistance up to approx. 90 ° C, whereby - despite a pigment set deviating from the purple bacteria - the electron transfer processes take place in a similar way (R. Feick et al. In: Reaction Centers of Photosynthetic Bacteria, ed. ME Michel-Beyerle, Springer-Verlag 1990, p. 181). As an alternative to photosynthetic reaction centers, artificial donor-acceptor systems are manufactured and their electron transfer properties are investigated. By HA Staab et al. (Chem. Ber. 127 (1994) 231; Ber. Bunsenges. Phys. Chem. 100 (1996) 2076; Chem. Phys. Lett. 209 (1993) 251) porphyrin-quinone cyclophanes are produced and characterized as artificial photosynthetic reaction centers , They consist of at least one porphyrin as donor (D), which is bridged with at least one quinone as acceptor (A), and change to the charge-separated state D + A- upon optical excitation.

WO 00/19550 describes artificial photosynthetic reaction centers consisting of a triad of a porphyrin which is connected to a fullerene electron acceptor (A) and a carotenoid electron donor (D). This triad also changes into the charge-separated state D + A- through photo-induced electron transfer. Since its life is strongly dependent on the magnetic field, the use of this triad as a magnetically controlled optical or optoelectronic switch is proposed.

WO 00/42217 describes a nucleic acid oligomer to which a donor-acceptor complex, in particular an RC or an artificial system, is linked. The setup is used to transfer charges to the oligomer and thus to detect its hybridization state electrochemically.

Self-organizing systems for the production of nanostructured systems, in which smaller molecular building blocks self-assemble to form larger units, are described in Whitesides et al. (Science 254 (1991) 1312). Proteins and nucleic acids in particular are proposed as building blocks for this molecular nanotechnology (CM. Niemeyer et al., Biospektrum 1 (1999) 31; K.E. Drexler et al., Proc. Natl. Acad. Sei. USA 78 (1981) 5275). In J. Mbindyo et al. (Advanced Materials 13 (2001) 249) states that gold nanowires can be self-assembled by modification with DNA.

In M. Scheffler et al. Trisoligonucleotides, ie branched oligonucleotides, which are linked at the 3 'ends by a trifunctional linker, are described and a method is given as to how complex nanostructures can be constructed from them by means of self-organization. Presentation of the invention

This is where the invention comes in. The object of the invention, as characterized in the claims, is to provide molecular electronic components with which nanoelectronic circuits can be constructed simply and effectively.

This object is achieved according to the invention by the molecular electronic component according to claim 1 and claim 2, the molecular electronic assembly according to claim 23, and the electronic circuit according to claim 31. The invention also provides a method of manufacturing an electronic circuit according to claims 32 and 33. Further embodiments of the invention emerge from the subclaims.

According to the invention, a molecular electronic component for constructing nanoelectronic circuits comprises a redox-active unit with an electron donor and an electron acceptor, the electron donor and the electron acceptor each having a contact point for linking to other components, and the contact points carrying a charge carrier to the component and from the component enable away. The contact point between the electron donor and the electron acceptor each represents a permanent contact point for mediating charge carrier transport via a permanent chemical bond, the contact point each comprising one of the binding partners of the chemical bond.

According to another embodiment of the invention, a molecular electronic component for the construction of nanoelectronic circuits comprises a redox-active unit with an electron donor and an electron acceptor, the electron donor and the electron acceptor each having a contact point for linking to other components, and the contact points transporting a charge carrier to that Allow component and away from the component. A first of the contact points of the electron donor and electron acceptor represents a permanent contact point for mediating charge carrier transport via a permanent chemical bond, the first contact point comprising one of the binding partners of the chemical bond. A second of the contact points of the electron donor and the electron acceptor is a temporary contact point for arranging the charge carrier transport without permanent connection of a substance to the contact point. In the context of the invention, a redox-active unit is understood to mean a unit with at least one electron donor and at least one electron acceptor. The terms electron donor and electron acceptor refer to redox-active substances. An electron donor is a molecule that can transfer an electron to an electron acceptor immediately or after exposure to certain external circumstances. Conversely, an electron acceptor is a molecule that can accept an electron from an electron donor immediately or after the action of certain external circumstances. Such an external circumstance is e.g. B. the light absorption by the electron donor or acceptor of a photo-inducible redox-active unit. By irradiating light of a certain or any wavelength, the electron donor D gives an electron to the / an electron acceptor A and, at least temporarily, a charge-separated state D ⁺ A ^" of oxidized donor and reduced acceptor is formed. Another such External circumstances can be, for example, the oxidation or reduction of the electron donor or acceptor of a chemically inducible redox-active unit by an external oxidizing or reducing agent, for example the transfer of an electron to the electron donor by a The ability to act as an electron donor or acceptor is relative, ie a molecule that is immediately or after the action of certain external circumstances compared to a molecule other than a reducing agent or an electron is released by the electron acceptor to an oxidizing agent Electron donor acts, can against this molecule under different experimental conditions or against one third molecule under the same or different experimental conditions also act as an electron acceptor. For further details and definitions, reference is made to the section “Photo-inducible and chemically inducible redox-active units” of the German laid-open specification DE-A-199 26457, the disclosure of which is included in the present application in this respect.

The invention is therefore based on the idea of providing a complex of an electron donor and an electron acceptor with specific contact points and using it as a molecular electronic component which can be linked to other components via its contact points in order to construct extremely miniaturized electronic circuits.

By linking two or more such components via the contact points, electronic assemblies are created which, in terms of their electrical function, can form, for example, a logic gate, a memory element, an amplifier or a sensor. By connecting a module or several modules connected via linear connection molecules to an electrically conductive surface, an electronic circuit is created which can be operated from the outside in the usual way via connections of the conductive surface.

One method of making an electronic circuit is in solution

- at least one first component added, one component comprising a aforementioned component, a aforementioned molecular electronic assembly, or a conductive linear connecting molecule, - at least one further component added, the first and the further component each having a permanent contact point with mutually associated binding partners , so that the first and the further component connect to one another at the assigned contact points in the solution,

- The step of adding further components is repeated, the further component and one of the already connected components each having a permanent contact point with mutually associated binding partners, so that the components connect to one another at the assigned contact points in the solution until a number of predetermined components is interconnected, and

- The interconnected components are placed on a conductive surface.

Alternatively, the circuit can be constructed from the conductive surface. Then a conductive surface is provided and it becomes in solution

- added at least one first component and linked to the conductive surface, - added at least one further component, the first and the further component each having a permanent contact point with mutually assigned binding partners, so that the first and the further component are at the assigned contact points connect with each other in the solution,

- The step of adding further components is repeated, the further component and one of the already connected components each having a permanent contact point with mutually associated binding partners, so that the components connect to one another at the assigned contact points in the solution until a number of predetermined components is connected.

It is a particular advantage of a method according to the invention that the electronic circuit is produced in a self-organized manner, since the mutually corresponding binding partners of the assigned contact points are in the solution connect. Components of the same type can also be connected to one another in large numbers at the same time.

Further advantageous refinements, features and details of the invention result from the dependent claims, the description of the exemplary embodiments and the drawings.

Brief description of the drawings

The invention will be explained in more detail below on the basis of exemplary embodiments in conjunction with the drawings. Only the elements essential for understanding the invention are shown. It shows

Fig. 1a linkage of two molecular conductors (a functionalized polyacetylene and a phenylazetylene) via carboxy and amino contact points. To avoid polymerization, a Boc-protected amino group is used instead of a second amino contact point (right in the picture). N-hydroxysulfosuccinimide (s-NHS) and (3-dimethylaminopropyl) carbodiimide (EDC) are added to form the amide bond. After the link has been established, the protected amino group can be deprotected and used as a further contact point.

1b Specific linkage of two molecular electrical conductors consisting of double-stranded nucleic acid oligomers (A, C, G, T) with two contact points each (K1 and K2 or K2 and K3) consisting of single-stranded nucleic acid oligomers (sequences S1 and S2 or . S2 and S3). For this purpose, the sequences S2 and S2 to be linked must be complementary to one another, which is expressed by the underline (S2). If the resistance of the double-stranded nucleic acid oligomer is not negligible in comparison to the other components in a circuit (typically for oligomers with more than 20 base pairs), the corresponding component is referred to as the molecular resistance. A symbolic representation of molecular resistances is shown on the right in the picture.

Fig. 1c linkage of a photosynthetic reaction center (RC) of Rb. sphaeroides via the quinone binding pocket to a molecular counterpart was standing. The molecular resistance in this example is a modified ubiquinone (UQmod), consisting of a chain of isoprenoid units and two contact points - a carboxy group and a quinone.

Fig. 2a molecular diode in the forward direction (UDA> Δφ).

Fig. 2b Molecular diode in reverse direction (UDA <0): The diode blocks in the voltage range 0> UDA> ÜB (left). If the diode voltage UDA exceeds the breakdown voltage ÜB, a current also flows in the reverse direction (right).

2c example of a molecular diode consisting of a bridged porphyrin-quinone system and two contact points K1 and K2. The porphyrin-quinone system consists of a donor D - a porphyrin - and an acceptor A - a quinone, which are bridged together twice. The

Donor is modified with a Boc-protected amino group - the contact point K1 - and the acceptor with a carboxy group as the contact point K2. In the exemplary embodiment, the radicals R stand for methyl groups (standard) or hydrogen atoms, other alkyl groups, methoxy groups, halogens and halogenated groups. A symbolic representation of this diode is shown on the right in the picture.

Fig. 3a example of a molecular photodiode consisting of a photosynthetic reaction center of Rb. sphaeroides (RC) and two contact points K1 and K2. The RC in particular comprises a donor D - the primary

Donor or special pair (P) - and an acceptor A - the quinone Q provided with a carboxy group. With optical excitation (hv) there is an electron transfer from P to Q - the state P + Q- is formed. The positive charge on P can be tapped via the contact point K1 - a specific binding pocket for cytochrome c + (cyt c +). The electron on Q can be withdrawn via the contact point K2 - the carboxy group of the modified quinone. Ultimately, a photocurrent flows through continuous light-induced electron transfer.

Fig. 3b example of a molecular photodiode consisting of a bridged

Porphyrin-quinone system and two contact points K1 and K2. In contrast only the donor-acceptor distance to the system in FIG. 2c is increased by the use of extended bridging molecules.

3c example of a molecular photodiode consisting of a double-bridged porphyrin-quinone-quinone system and two contact points K1 and K2. In addition to an acceptor A which is substituted by the contact point K2 and a chlorine atom, this exemplary embodiment comprises an intermediate acceptor I via which the electron transfer from D to A is mediated.

FIG. 3d example of a molecular photodiode consisting of a bacteriochlorophyll derivative as donor D and a pyrrolo-quinolino-quinone as acceptor A, which are bridged together, a permanent contact point K2 and a temporary contact point K1. A zinc atom is preferably used as the central atom M of the bacteriochlorophyll derivative. The external reducing agent (Red) enables electron transfer to the donor via the contact point K1.

4a example of a molecular NPN transistor based on a double-bridged quinone-porphyrin-quinone system. Collector C and emitter E both consist of a quinone, each with a contact point KC and KE, and are bridged with base B - a porphyrin with the associated contact point KB. A symbolic representation of this transistor is shown on the right in the picture.

Figure 4b energy scheme and principle of operation of a molecular NPN transistor.

FIG. 5 Procedures for the combination and contacting of molecular electronic components using the example of contacting a molecular diode via a molecular conductor on a gold surface: a) structure of the system in solution and subsequent application on the surface, b)

Gradual construction of the system on the surface.

FIG. 6 Example of a molecular inverter on a chip 100 with micro contacts

111 and macroscopic connections 112, comprising a molecular transistor 10, a molecular resistor 20 and a connecting piece

30. The connection of the molecular components is made via contact points made of oligonucleotides. Ways of Carrying Out the Invention

1. Contact points, molecular electrical conductors and resistors

First, contact points, molecular electrical conductors, and resistors as used in the molecular components of the invention are exemplified.

Examples of contact points used in the invention are: a) Functional chemical groups, such as amino groups and coupling groups that can be specifically linked to them (eg carboxy and hydroxyl groups, isothiocyanates, sulfonyl chlorides, aldehydes and activated esters, in particular succinimidyl esters) or thiol groups and coupling groups that can be specifically linked to them (e.g. alkyl halides, haloacetamides, maleimides, aziridines and symmetrical disulfides) or hydroxyl groups and groups that can be specifically linked to them (e.g. acyl azides, isocyanates, acyl nitriles and acyl chlorides) or aldehydes, Ketones and specifically linkable groups (e.g. hydrazines and aromatic amines).

The functional chemical groups or the coupling groups can in some cases be provided with protective groups to block certain linkages. As a result, two similar functional chemical groups can be used. First of all, the group is initially protected and only the other is available for a reaction. In this way, only the desired compounds are entered into and polymerization is avoided. After the first reaction has ended, the protective group for the second reaction can be removed, ie the protected group can be deprotected.

In FIG. 1a, for example, the linkage of a carboxy contact point of a molecular conductor with an amino contact point group of another conductor is shown. In order to avoid polymerization and still allow a further linkage, one of the two amino functions is provided with a Boc protective group, which can be deprotected in an acidic environment after the linkage of the two conductors. Boc stands for tert-butoxycarbonyl (-CO-OC (CH ₃ ) ₃ ).

b) Single-stranded nucleic acid oligomers with a specific sequence. Preferably DNA, RNA or PNA oligonucleotides consisting of 5 to 30 - are shown Example 12 - Nucleotides used. In this way, a large number of different specific contact points can be realized. FIG. 1 b shows a specific linkage of two molecular electrical conductors consisting of double-stranded nucleic acid oligomers (A, C, G, T) with two contact points each (K1 and K2 or K2 and K3) consisting of single-stranded nucleic acid oligomers (sequences S1 and S2 or S2 and S3). A, G, C and T stand for adenine, guanine, cytosine and tymin, ss for single strand (d strand) and ds for double strand (double strand). For this purpose, the sequences S2 and S2 to be linked must be complementary to one another, which is expressed by the underline (S2). If the resistance of the double-stranded nucleic acid oligomer is not negligible compared to the other components in a circuit (typically for oligomers with more than 20 base pairs), the corresponding component is referred to below as the molecular resistance. A symbolic representation of molecular resistances is shown on the right in the picture.

c) Specific binding sites on proteins and enzymes and their respective binding partners, for example in the photosynthetic reaction center (RC) the quinone binding pocket and the docking site for the cytochrome c in the vicinity of the bacteriochlorophyll dimer or the biotin binding pocket of the avidin. Figure 1c shows, for example, the linkage of a photosynthetic reaction center of Rb. sphaeroids through the quinone binding pocket to a molecular resistor, in this case a modified ubiquinone. This consists of a chain of isoprenoid units with two terminal contact points - a carboxy group at one end and a quinone at the other end. The latter fits exactly into the binding pocket of the reaction center and, like the natural ubiquinone, forms a specific binding therein.

The production of this ubiquinone with a reactive side group is described in patent application DE 100 57 415, the disclosure content of which is included in the scope of the present application. To link RC and modified ubiquinone, the natural ubiquinone is first extracted from the RC and then the RC is reconstituted with the modified ubiquinone with an empty binding pocket (Gunner, MR, Robertson, DE, Dutton, PL, 1986, J. Phys. Chem., Vol. 90, 3783-3795, see WO 00/42217).

d) Photoactivatable crosslinkers, such as aryl azides and benzophenone derivatives. e) Complex-forming ions, in particular transition metal ions, and ligands associated therewith, for example oligopyrroles.

f) Temporary contact points comprising a redox-active substance that is accessible to another redox-active substance in solution and can exchange an electron with it in a certain potential range. An example of this temporary contact point is shown in Figure 3d and is described in more detail below.

In the context of this invention, a distinction is made between permanent contact points, which impart electrical conductivity via a permanent chemical bond, and temporary contact points, which impart electron transfer to dissolved redox-active substances, without these substances being permanently bonded to the contact point. Categories a), b), d) and e) of the examples mentioned are permanent contact points. This also applies to the biotin binding pocket and the quinine binding pocket of category c), which each form a stable binding with a biotin or a quinone. The docking point for the cytochrome c binds it only temporarily and is therefore, like category f), to be assigned to the temporary contact points.

Molecular ladder

Conductive molecules or crystals are used as molecular electrical conductors (wires), which are provided with contact points at both ends.

Examples of molecular wires include linear, unsaturated hydrocarbons, in particular polyacetylenes (CH) _X (Fig. 1a left), Carbyne C _x , sulfur-nitrogen polymers (SN) _X and polypyrroles and phenylazetylenes (oligo-phenylethynyls, Fig. 1a) right), as well as double-stranded nucleic acid oligomers (e.g. Fig. 1b: DNA, RNA or PNA), biological nerve cells, carbon nanotubes (nanotubes), silicon nanowires and conductive organic crystals, such as fluoranthene, perylene hexafluorophosphate or others Radical cation salts of the arenes.

Molecular resistance

Each of the above-mentioned molecular wires can be used as electrical resistance if the length of the wire is selected so that the desired resistance is achieved given the specific conductivity of the wire (cf. FIG. 1b). In addition, resistors can be built into the above wires as follows: a) In the case of wires made of unsaturated hydrocarbons, the electrical resistance increases by incorporating individual saturated carbon atoms.

b) For wires made of double-stranded nucleic acid oligomers, the resistance is increased by the incorporation of base mismatches or sections of single-stranded nucleic acid oligomers.

c) The conductivity properties of nanocarbon tubes are changed by the incorporation of foreign atoms (doping).

2. diode

In a preferred embodiment, the donor-acceptor complex according to the invention is used as a rectifying diode - in analogy to a semiconductor diode, the donor corresponding to the p-doped semiconductor and the acceptor corresponding to the n-doped semiconductor. The mode of operation is explained with reference to FIG. 2.

Diode in the forward direction (FIG. 2a): In order to operate the diode according to the invention in the forward direction, a voltage U _DA > Δφ is applied to the donor-acceptor complex such that the donor D is at a potential φ _D > φ _{D D +} and the acceptor A at a potential φ _A <q> p _A. located. Φ _{D D +} denotes the potential at which the neutral and the oxidized form of the donor are in equilibrium with the same probability, Φ _AA - the potential at which the neutral and the reduced form of the acceptor are in equilibrium with the same probability, and Δφ = φ _{D D +} - ψ _MA . the difference between the two potentials.

When these potentials are applied, the donor is oxidized via its electrical contact and the acceptor is reduced via its electrical contact, so that the charge-separated state D ⁺ A ^" arises. For use as a diode, the donor-acceptor complex is optimized according to the invention in such a way that that a quick recombination of the state D ⁺ A ^{"is possible} due to an electron transfer from A ^" to D ⁺ . This can be done, for example, by reducing the distance between the donor and acceptor or by selecting donors and acceptor with suitable energy levels. The recombined State DA is in turn brought into a charge-separated state by a current flow through the electrical contacts, and due to continuous recombination, a current flows in the forward direction as long as voltage U _DA is present. Reverse diode (Fig. 2b):

If a voltage U _DA <Δφ is applied to the diode, the donor-acceptor complex remains in the basic state DA. If no energy is added from the outside, for example by irradiation of light or thermal energy, the generation rate, ie the rate of formation of the charge-separated state D ⁺ A ^"is low (at T = 0 it is zero). There is no charge separation and therefore no current flow - the diode blocks (Fig. 2b, left in the picture).

As with a semiconductor diode, a breakdown occurs in the molecular diode when the reverse voltage is too high: If the reverse voltage is larger than the breakdown voltage U _B = φ _DD . If φ _{A / A + is} applied such that the donor D is at a potential φ _D <φ _{D D-} and the acceptor A is at a potential φ _A > φ _A / _{A +} , the charge-separated state D ^" A ^{+ is formed} Where φ _{D /} o- denotes the potential at which the neutral and the reduced form of the donor are in equilibrium with the same probability, φ _{AA +} the potential at which the neutral and the oxidized form of the acceptor are in equilibrium with the same probability State D ^" A ⁺ recombines immediately due to an internal electron transfer. The recombined state DA is in turn brought into the charge-separated state by a current flow through the electrical contacts. Due to continuous recombination, a current also flows in the reverse direction as long as a reverse voltage is present above the breakdown voltage U _D (FIG. 2b, right in the picture).

Example of a donor-acceptor complex that can be used as a diode: An example of the molecular diode according to the invention is based on a bridged porphyrin-quinone system (cf. Staab, HA; Krieger, C; Anders, C; Rückemann, A., Chem. Ber. 1994, 127, 231-236) and additionally includes a contact point for the porphyine as donor D and the quinone as acceptor A (Figure 2c). The porphyrin-quinone system consists of a donor D - a porphyrin - and an acceptor A - a quinone, which are bridged together twice. The donor is modified with a Boc-protected amino group - the contact point K1 - and the acceptor with a carboxy group as the contact point K2. In the exemplary embodiment, the radicals R stand for methyl groups (standard) or hydrogen atoms, other alkyl groups, methoxy groups, halogens and halogenated groups. A symbolic representation of this diode is shown on the right in the representation of FIG. 2c. The contact point of the quinone consists of a carboxy group, through which chemical bonding and electrical contacting of the acceptor (at the potential φ _A ) is possible. The contact point of the porphyrin is a Boc-protected amino group for chemical bonding and electrical contacting of the donor (at the potential φ _D ).

The oxidation and reduction potentials of these porphyrin-quinone systems are of the following order of magnitude (in dichloromethane, potentials relative to ferrocene): φ / _D + = +0.3 V, Φ _A / A- = -1, 3 V, φ _D / _D - ~ -, 4 V, Φ _{A /} A ₊ > 0.4 V. This results in a threshold voltage of Δφ = 1, 6 V, above which the diode becomes conductive. For the blocking behavior, in addition to the diode itself, the properties of the environment or the solvent must be taken into account. For example, an electrolysis current flows in water above a potential of +1.1 V. If environmental effects are irrelevant, the reverse breakdown voltage is approx. U _B = φ _{D / D.} - Φ _{AA +} = - 2.8 V.

The recombination time from the charge-separated state D ⁺ A ^" was determined to be approximately 40 ps (Pöllinger, F .; Musewald, O; Heitele, H .; Michel-Beyerle, ME; Anders, O; Futscher, M .; Voit, G .; Staab, HA Ber. Bunsenges. Phys. Chem. 1996, 100, 2076-2080). Provided that the electron transfer via the contact points does not determine the speed, that is to say it takes less than 40 ps, a maximum forward current results of 4 nA per molecule.

3. Photodiode

In order to use the donor-acceptor complex according to the invention as a photodiode, the complex is operated below the forward voltage or in the blocking direction, ie a voltage U _A <Δφ is applied. The complex is optimized to the extent that when irradiated with electromagnetic radiation, in particular light, the generation rate of state D ⁺ A ^" when exposed to light is as large as possible and the recombination rate is as low as possible. In addition, the photodiode is arranged in such a way that external irradiation with light is possible is, in particular that translucent materials are used for contacting and insulation of the photodiode on the side facing the radiation.

An example of a complex suitable as a photodiode that has already been optimized by nature is the reaction center of photosynthesis (FIG. 3a). For example, the bacterial reaction centers (RC) of Rb. sphaeroides when irradiated with light stimulated for efficient charge separation in the visible or near infrared range. An electron transfer from the primary donor D (P) over several intermediate steps to a quinone Q (or acceptor A) takes place within a period of 200 ps, which results in the state P ⁺ Q ^" . (The RC has one more Quinone binding pocket for a second quinone Q _B as subsequent acceptor. However, this second quinone is only very weakly bound and is no longer available after the exchange of the first quinone Q (see Section 1c). Due to low recombination rates, the charge separation takes place with a quantum yield of If the primary donor P and the quinone Q are contacted, the current flow through the contacts, which is caused by the light-driven charge separation, can be tapped off. Contacting P is possible, in particular, by the natural cytochrome c (cyt c), the an the specific contact point K1 on the RC. This molecule can donate an electron to the oxidized donor P ⁺ by moving it from the state positively charged Cyt c ^{+ changes} into the state positively charged Cyt c ²⁺ . In addition, it takes over the charge transport in solution to a counter electrode, to which it can be reduced again. The quinone Q is modified with a carboxy group, which serves as a second contact point K2, via which the component can be connected, for example, to a gold electrode.

The quinone can be provided by a chemical modification (patent application DE 100 57 415, the disclosure of which is included in the scope of the present application) with a carboxy group, which serves as a second contact point via which a functional connection is possible. The connection can be made to a molecular conductor and / or to a conductive surface, for example to a gold surface covered with amino-terminated thiols.

An alternative way of providing the RC with contact points is to covalently bind functional groups to the protein matrix of the RC in the immediate vicinity of the donor or the acceptor. In particular, the RC can be connected via a photoactivatable linker, for example benzophenonic acid (BPA).

Provided that the electron transfer via the contact point K2 is not speed-determining, the following photocurrents can be achieved per molecule:

The electron transfer time from the cyt c to the primary donor P determines the rate for the transfer of the first electron. It is approx. 1 μs, which results in Inrush current of 0.2 pA results. In the stationary case, with sufficient illumination of the RC (at least 3 * 10 ⁴ absorbed photons per second), the diffusion time of the cyt c is limiting.

It depends on the geometry of the overall arrangement and the concentration of the cyt c and is approximately 300 μs (R.K. Clayton & W.R. William (Ed.)., The Photosynthetic Baceria, Plenum Press 1978, p. 446). This results in a maximum steady-state photocurrent of 0.5 fA per molecule.

If the molecular photodiodes are applied to a gold surface via the contact point K2 with a density of one molecule per (10 nm) ² , the maximum stationary photocurrent density is 0.5 mA / cm ² .

Further examples of donor-acceptor systems that can be used for molecular photodiodes are, in particular, thermophilic reaction centers of Chloroflexus auranticus and artificial donor-acceptor systems, such as the above-mentioned porphyrin-quinone system.

In the case of the porphyine-quinone system, very good photocurrents per molecule can be achieved with good contacting, ie contacting with high conductivity, since the electron transfer to form the charge-separated state D ⁺ A ^" takes only a few picoseconds with optical excitation. Due to the fast recombination time of the system, the efficiency of this embodiment is limited.To reduce the recombination as a competitive process for deriving the charge carriers via the contact points, donor-acceptor systems with one or more intermediate states (as in the case of the RC described above) or systems with 3b shows such a porphyrin-quinone system, the donor-acceptor distance of which compared to the system shown in FIG. 2c is increased due to longer bridging (HA Staab, Achim Feurer, Claus Krieger, A. Sampath Kumar: Distance Dependence of Photoinduced Electron Tr ansfer: Syntheses and Structures of Naphthalene-Spacered Porphyrin-Quinone Cyclophanes. Liebigs Ann. (1997), 2321-2336). A reduction in the recombination rate can also be achieved by using a system consisting of more than two redox-active substances, for example a system consisting of a porphyrin and two quinones arranged one behind the other (F. Pöllinger, H. Heitele, ME Michel-Beyerle, M. Tercel and HA Staab: Stacked Porphyrin-Quinone Triads as Models for the Primary Charge-Separation in Photosynthesis, Chem. Phys. Lett. 209 (1993) 251). The molecular based on it In addition to this phorphyrin-quinone1-quinone2 system, the photodiode comprises an amino group as contact point K1 on the porphyrin and a carboxy group as contact point K2 on the quinone2 (FIG. 3c).

Another donor-acceptor system that can be used as the basis for a molecular photodiode is described in patent application WO 00/42217. Figure 3d shows a corresponding embodiment, consisting of a bacteriochlorophyll derivative (BChl) as donor D and a pyrrolo-quinolino-quinone (PQQ) as acceptor A, which are bridged together, and the contact points K1 and K2. A zinc atom is preferably used as the central atom M of the bacteriochlorophyll derivative. In this system, the charge-separated state D ⁺ A ^" is formed by absorption of light of the wavelength 770 nm. The contact point K1 designates the outside of the BChl (in FIG. 3d above), which for ferrocyanate acts as an external reducing agent (Red). is accessible, which enables a specific re-reduction of the oxidized donor D ⁺ at the redox potential of the donor φ _{D D +} = +0.4 V. The contact point K2 on the acceptor is in turn a (Boc-protected) amino group, via an electron from the reduced one Acceptor can be deducted.

4. Solar cell

The photodiodes according to the invention function as solar cells if no external bias is applied. When the donor-acceptor complex is irradiated, the charge-separated state D ⁺ A ^" arises, and thus an internal voltage U ₊ A-, which can be tapped from the outside via the electrical contacts of the donor and the acceptor. If the circuit is closed externally, it is the current flow is maintained by repeated light-driven charge separation in the solar cell.

The power emitted by the solar cell is U ₊ A- * ' _ET , where U _{D + A} - the potential difference between the charge-separated state D ⁺ A ^" and the ground state DA and I _E τ = k _E τ * e with the electron transfer rate k _E τ and the elementary charge e = 1, 6 * 10 ^"19 C indicates the current.

In the bacterial reaction center of Rb. When irradiated with photons with a minimum energy of 1.37 eV, a voltage of U _{D + A} - = 0.5 V is generated (RK Clayton & WR William (Ed.)., The Photosynthetic Bacteria, Plenum Press 1978, p. 441 ff .). The internal charge separation rate is k _ET = (200 ps) ^"1 , which results in a maximum current of 800 pA and a power of 3.2 nW per complex results. However, this performance can only be achieved with ideal, ie lossless, contacting.

When the donor of the reaction center contacts the natural cytochrome c, the charge transport rate in the stationary case is limited by the diffusion rate of this molecule and is about 300 μs (see above). The acceptor is contacted directly to a conductive surface via a molecular conductor, so that the charge transfer rate of this contact is not speed-determining. This type of contacting results in a current of 0.5 fA per complex for the overall system with k _E τ = (300 μs) ^"1 .

A maximum of 10 ¹³ reaction centers per cm ² can be applied to a flat electrode. With this arrangement, a current density of 5 mA / cm ² and a power density of 2.5 mW / cm ^{2 is} achieved.

When using rough or porous electrode surfaces, the coverage density is increased by up to a factor of 100 compared to a flat electrode. This enables correspondingly higher current and power densities to be achieved. In order to increase the efficiency of the solar cell, as with natural systems, light collector complexes, in particular from bacteriochlorophylls, can be arranged around the primary donor. Overall, these increase the absorption cross section, transfer their excitation energy to the primary donor of the RC and thus contribute to increasing the efficiency of the molecular solar cell.

5. Sensor

The electron transfer properties of the diode according to the invention can be influenced not only by light but also by other physical quantities. If the influence is significant in one embodiment, this embodiment can be used as a sensor for the corresponding size. In particular, the following embodiments can be implemented:

5a. temperature sensor

The temperature sensor is characterized by a significant dependence of the diode current on the temperature. Two embodiments can be distinguished, a) a temperature sensor based on a diode operated in the forward direction and b) a temperature sensor based on a diode operated in the reverse direction.

5aa) Temperature sensor based on a diode operated in the forward direction

Embodiment 5aa is implemented when the recombination rate is significantly temperature-dependent. Such a temperature dependency exists if the recombination takes place via a thermally occupied intermediate state - for example an electronically excited state, in particular D * or A *. Thus the recombination rate and thus the forward current increases with increasing temperature.

An example of this type of temperature sensor is the porphyrin-quinone system described in FIG. 2c when all the substituents R are methyl groups. In this system, the state D * is energetically higher than the charge-separated state D ⁺ A ^" with an enthalpy difference which at room temperature is of the same order of magnitude as the thermal energy k _B T = 0.025 eV (T. Häberle, dissertation, TU Munich 1995, p. 81. The recombination can therefore take place thermally activated via the state D * and is therefore strongly temperature-dependent, which means that the forward current of the photodiode is also strongly temperature-dependent.

5ab) Temperature sensor based on a diode operated in the reverse direction

Embodiment 5ab is implemented when the generation rate is significantly temperature-dependent. Such a temperature dependency exists if the charge-separated state can be thermally occupied when a reverse voltage is applied. The generation rate and thus the reverse current increase with increasing temperature.

The porphyrin-quinone system shown in Figure 2c is an example of this type of temperature sensor when the substituents R on the porphyrin are methyl groups but that on the quinone is a methoxy group. In this system, the charge-separated state D ⁺ A ^"is energetically higher than the state D * with an enthalpy difference which at room temperature is of the same order of magnitude as the thermal energy k _B T = 0.025 eV (T. Häberle, dissertation, TU Munich 1995, p. 81) If this system is illuminated with light of wavelength 630 nm, the excited state D * is formed, from which the charge-separated state D ⁺ A ^" can be formed by thermal activation. The generation rate and thus the reverse current of the molecular diode is therefore strongly temperature-dependent. 5b. pressure sensor

Applying pressure to the donor-acceptor complex generally reduces the distance between the donor and acceptor, increasing the interaction between them and the rate of recombination. The diode current therefore increases with the pressure. A particularly strong pressure dependence of the diode current is achieved in donor-acceptor complexes in which the distance between donor and acceptor is very flexible and a large relative change in distance is associated with an increase in pressure.

Examples of the pressure sensor according to the invention are the bridged phorphyrin-chionone system shown in FIG. 3b and the bacteriochlorophyll-PQQ- shown in FIG. 3c

System. The latter is more sensitive to pressure due to the simple bridging.

5c. Acceleration sensor If the donor and acceptor each have a large mass, a force acts on them when the sensor accelerates, which force can change the geometry of the donor-acceptor complex and thus the recombination rate. A pressure sensor of embodiment 5b is particularly suitable for this, in which substances with a large mass are bound to both the donor and the acceptor.

An example of the acceleration sensor according to the invention is the bacteriochlorophyll-PQQ system shown in FIG. 3c, which on the one hand directly on an electrode - preferably with the quinone on a gold electrode - and on the other hand additionally on a heavy molecule - preferably a fullerene (C60 molecule) - is attached.

6. LED

The light-emitting diode (LED) is based on a diode described under point 2, which is operated in the forward direction. The diode emits radiation when the state D ⁺ A ^" formed by the external voltage recombines in a radiating manner. For this purpose, it is necessary that an electronically excited state, in particular D * or A *, can be occupied from the state D ⁺ A ^" , which is radiating passes into the basic state.

An example of such a donor-acceptor complex is the porphyrin-quinone system already described under 5ab with a methoxy substituent on the quinone, the charge-separated state D ⁺ A ^{"of which is} energetically above the excited state D * of the donor Diode operated in the forward direction is formed by the outer one Voltage is the charge-separated state that can recombine into the excited state D *. This excited state decays with radiation and emits light in the spectral range between 600 and 750 nm.

The diodes can also be arranged in a grid in a matrix that can serve as a display element. In this way, digit or letter displays or two-dimensional displays consisting of dot matrices can be produced.

7. Optocoupler

The optocoupler according to the invention consists of a combination of an LED described under point 6 with a photodiode described under point 3. The two components are arranged side by side so that the radiation emitted by the LED preferably strikes the photodiode. They are matched to one another in such a way that the radiation emitted by the LED has sufficient energy - based on both the number and the frequency of the photons - to drive the photodiode. Such an optocoupler can be used to transmit an electrical signal that is applied to its input (the LED) to its output (the photodiode) without the input and output being electrically connected to one another. An electrical decoupling of the signals is thus achieved.

An example of such an optocoupler consists of the LED described in section 6, which with the photodiode according to the invention, consisting of the photosynthetic reaction center of Rb. sphaeroides, near the primary donor D is covalently linked. When a voltage is applied to the LED, it emits light in the spectral range 600 to 750 nm, which is absorbed by the pigments of the RC and whose primary donor switches to the electronically excited state D *, from which the charge-separated state D ⁺ A ^" is formed. The voltage that forms can be tapped between the donor and acceptor, or the contact points K1 and K2 of the RC as outputs of the optocoupler.

8. transistor

The molecular transistors according to the invention comprise three redox-active substances - either an electron donor and two acceptors (NPN transistor) or an acceptor and two donors (PNP transistor). The three redox-active substances are arranged one behind the other so that the donor and acceptor alternate. As well arranged in such a way that the donor and acceptor alternate. As with semiconductor transistors, the two external substances are referred to as emitters and collectors and the middle substance as the base.

An NPN transistor is described below by way of example, the emitter and collector of which each consist of a quinone (electron acceptor) and whose base consists of a porphyrin as (electron donor). An exemplary embodiment based on a double-bridged quinone-porphyrin-quinone system (cf. F. Pöllinger, dissertation, TU Munich 1993, p. 49) is shown in FIG. 4a. The molecular NPN transistor shown there is based on a double-bridged quinone-porphyrin-quinone system. Collector C and emitter E both consist of a quinone, each with a contact point KC and KE, and are bridged to the base B - a porphyrin with the associated contact point KB. A symbolic representation of this transistor is shown on the right in the picture. The principle of operation of such a molecular transistor is shown in FIG. 4b.

The NPN transistor according to the invention acts as an electrical switch or amplifier when the emitter is at a potential φ _E <Φ _{A / A} - (= -1.3 V in the exemplary embodiment) and the collector is at φ _c > ΦD _/ D ₊ (= 0.3 V) is maintained, ie the collector-emitter voltage U _{CE is} greater than the potential difference Δφ = φ _{D / D} + - ΦAA- (= .6 V). The transistor is switched on by applying a potential φ _B in the range φ _c > φ _B > CD / D ₊ to the base (FIG. 4b, case 1): in this circuit, the charge-separated state E ^~ B ⁺ C is formed in the transistor which recombines into the EBC state by means of an internal electron transfer. While the electron on the emitter is supplied directly via the emitter connection (emitter current I _E ), an electron can be withdrawn from the base in two ways. Either the base is oxidized directly via a base current l _B or a further internal electron transfer to the collector takes place, which finally leads back to the initial state E ^~ B ⁺ C via a collector current l _c . The gain p of the transistor V ≡ l _E / l _B = 1 / p results from the probability p that the electron is withdrawn via the base instead of the collector.

The transistor blocks when a potential φ _B <φ _{D / D + is} applied to the base (Figure 4b, case 2): The charge-separated state E ^~ B ⁺ C cannot develop in this circuit, which leads to an internal electron transfer and thus a Current flow is prevented.

To maximize the amplification factor V, the potential difference φ _c - φ _B must be chosen so large that the internal electron transfer from the base to the collector is possible. is without activation. In the porphyrin-quinone systems mentioned, for example, the activation-free electron transfer takes place at a potential difference of 0.8 V. In addition, the transistor component can be optimized in such a way that the electron transfer via the base connection works poorly, ie is activated more or is provided with a higher resistance than the transfer via the collector.

9. Combination of molecular components - self-organized construction of complex circuits

By connecting several of the molecular components listed above, electronic circuits can be built. In particular, the following two approaches are possible:

a) Structure of the circuit in solution

In one embodiment, the circuit is built up successively in solution, in that two components or assemblies are linked to the coupling chemistry specific for the common contact point. This linking of components or assemblies continues until an assembly is finished with the desired functionality. This finished assembly, consisting of a macromolecule or molecular conglomerate, is finally attached to a surface that is provided with specifically modified electrodes. The electrodes on the surface are each modified in such a way that a specific bond can be made to an as yet unlinked contact point. An example of this procedure is shown in FIG. 5 (route a).

Exemplary description of the method for producing a circuit in solution:

The structure of a simple circuit with a molecular diode and a molecular wire is described below as an example. For this, the phorphyrin-chionone system 10 ^"3 molar shown in Fig. 2c is added to an aqueous solution with 20% ethanol and 3x10 ^{" 3} molar conductor - for example the thiol and amino-terminated phenylacetylene shown in Fig. 5. By adding EDC (10 ^"2 molar) and sulfo-NHS (10 ^{" 2} molar) an amide bond is formed after a reaction time of approx. 1-4 hours between the amino group of the molecular conductor and the carboxy group of the phorphyrin Quinone system (EDC = (3-dimethylaminopropyl) carbodiimide, sulfo-NHS = N-hydroxysulfosuccinimide). The components thus obtained are chromatographically by means of HPLC cleaned and can then be connected to other components or directly to the surface via their unlinked contact points.

To contact the components on a surface, two nanoelectrodes with gold plating are produced at a distance of 1 nm. Suitable manufacturing processes are known from the semiconductor industry and are described, for example, by Porath et al. (Nature 403 (2000) 635) and Bezryadin et al. (J. Vac. Sci. Technol. B15 (1997) 411). The nanoelectrodes are structured using electron beam lithography in a SiN layer on an oxidized silicon substrate and sputtered with gold through a silicon mask. The structures obtained in this way are checked in an electron microscope. The structures whose nanoelectrodes are spaced between 0.5 and 1.5 nm are selected.

One of the two nanoelectrodes - the anode - is wetted with an aqueous solution of 3x10 ^'3 molar 3-mercapto-propionic acid via a nanopipette and incubated for 5-60 min. After rinsing with ultrapure water, a monolayer functionalized with carboxy groups remains on the anode. When treating the anode, always make sure that the other nanoelectrode - the cathode - remains as clean as possible. The surface is thus prepared for contacting the components described above. The components are pipetted onto the cathode in 3x10 ^"3 molar aqueous solution and incubated for 5-60 min. After rinsing with ultrapure water, a monolayer of molecular components remains on the cathode. By adding 95% trifluoroacetic acid (TFA) in dichloromethane, the Boc- Protected amino group on the phorphyrin is deprotected within 10 min After a further rinsing step, both electrodes are coated with an aqueous solution of EDC (10 ^'2 molar) and sulfo-NHS (10 ^"2 molar). Those molecular components on the cathode that are close enough (<1.5 nm) to the anode react within one hour with one of the carboxy groups on the anode. The result is a simple molecular electronic circuit with two nanoelectrodes that are connected to (at least) one molecular diode via molecular wires.

b) Structure of the circuit on the surface

In another embodiment, the circuit is successively applied to a surface. For this purpose, a component is first linked to a conductive surface and successively further components or assemblies are added to this surface structure. An example of this procedure is shown in FIG. 5 (route b). 10. Example of a circuit - an inverter

FIG. 6 shows a molecular inverter with macroscopic connections, made up of a molecular transistor 10, a molecular resistor 20, a connecting piece 30 and a chip 100 with four conductor tracks 110.

The conductor tracks are made of gold, which is deposited on a substrate (glass or plastic) using a structuring mask. They have micro contacts 111 at one end and macroscopic plug or solder contacts 112 made of bare gold at the other end, while the lines between them are electrically insulated by a coating (made of plastic, lacquer or long-chain alkane thiols). They are called G (ground), S (supply), I (input) and O (output) according to their electronic function. The four microelectrodes are arranged in a square in such a way that their tips are at a maximum distance of 10 nm and that I and O as well as G and S face each other. They are coated with thiol-modified oligonucleotides 90 consisting of 5 to 30 - in the exemplary embodiment 12 - nucleotides of different sequences.

For example, the double-bridged porphyrin-quinone system described above is used as transistor 10. It is provided with oligonucleotides of equal length at all three contact points. The sequence SJ at the base contact is complementary to the sequence SI at the micro contact of the conductor I and the sequence SG at the emitter contact is complementary to the sequence SG at the micro contact of the conductor G.

The molecular resistor 20 consists of an oligonucleotide which comprises a central double-stranded section of at least 12 - in the exemplary embodiment 24 - base pairs and at both ends a single-stranded section of the same length as at the contact points of the other components (contact points with the sequences SR and SS) , The sequence SS at one end of the resistor is complementary to the sequence SS at the micro contact of the conductor track S (supply).

In order to implement the node between the collector contact of the transistor, the resistor and the output microcontact, a connecting piece 30, consisting of a trisoligonucleotide (Scheffler M., et al. Angew. Chem. Int. Ed., Nov 15 1999, 38 ( 22) p3311- 3315). This consists of 3 oligonucleotides of the same length as the contact points of the other components, which are linked together at the 3 'end with a trifunctional linker. The trisoligonucleotide used has the property that the sequence of an oligonucleotide SC is complementary to the sequence SC of the collector Contact of the transistor, a second sequence SR complementary to the sequence SR of the resistor and the third sequence SO complementary to the sequence SO of the oligonucleotide applied to the microcontact of the conductor track O (output).

All sequences are selected in such a way that only those described above, which are explicitly described as complementary, hybridize with one another. The result is a self-organizing system which, when all of the substances mentioned are added to the four oligonucleotide-coated microelectrodes, reacts with one another so that the desired circuit is formed.

The circuit is connected via the macroscopic contacts. The supply voltage Vs = +2 V is applied to contact S in relation to connection G. Overall, it can be achieved that a voltage at input terminal I is output inverted at output terminal O, i.e. In particular, that a voltage increase at contact I from 0 V to 2 V leads to a reduction in the output voltage from 1 -2 V to 0-1 V.

Claims

claims

1. Molecular electronic component for constructing nanoelectronic circuits with a redox-active unit with an electron donor (D) and an electron acceptor (A), the electron donor and the electron acceptor (A) each having a contact point (K1, K2) for linking to other components, and the contact points (K1, K2) enable charge carrier transport to and away from the component, in which the contact point (K1, K2) of the electron donor (D) and electron acceptor (A) each have a permanent contact point for mediating the charge carrier transport via a permanent one is chemical bond, the contact point each comprising one of the binding partners of the chemical bond.

2. Molecular electronic component for building nanoelectronic circuits with a redox-active unit with an electron donor (D) and an electron acceptor (A), the electron donor (D) and the electron acceptor (A) each having a contact point (K1, K2) for linking to others Components and the contact points (K1, K2) enable a charge carrier transport to the component and away from the component, in which a first of the contact points (Fig. 3a: K2) of electron donor (D) and electron acceptor (A) a permanent contact point Mediation of charge carrier transport via a permanent chemical bond, the first contact point comprising one of the binding partners of the chemical bond, and a second one of the contact points (FIG. 3a: K1) of electron donor (D) and electron acceptor (A) being a temporary one Contact point for arranging the transport of the load carrier without permanent connection of a substance to the contact point.

3. The component according to claim 2, wherein the temporary contact point (Fig. 3a: K1) for unstable interaction between proteins or as a docking point for redox-active

Substances is set up.

4. Component according to one of the preceding claims, in which the permanent (n) contact point ^) to form a covalent bond or a permanent ligate-ligand interaction, in particular a nucleic acid interaction, a stable interaction between proteins, an antigen-antibody Interaction or an ion-ligand interaction is established.

5. Component according to one of the preceding claims, in which the redox-active unit additionally comprises one or more macromolecules, in particular further electron donor and electron acceptor molecules.

Component according to one of the preceding claims, in which the redox-active unit is the native or modified reaction center of photosynthetic organisms, in particular the native or modified reaction center of photosynthetic bacteria.

7. Component according to one of claims 1 to 5, in which the electron donor (D) and electron acceptor (A) are part of a donor-acceptor complex, in particular a pigment-protein complex, the reaction center of Rhodopseudomonas viridis, the reaction center of Rhodobaoter sphaeroides, the reaction center of thermophilic bacteria or the Chloroflexus aurantiacus.

8. The component according to one of claims 1 to 5, in which the electron donor (D) and / or the electron acceptor (A) are dyes, in particular flavins, (metallo-) porphyrins, (metallo-) chlorophylls or (metallo-) bacteriochlorophylls or Derivatives thereof.

9. The component according to one of claims 1 to 5, in which the electron donor (D) and / or the electron acceptor (A) are nicotinamides or quinones, in particular pyrrolo-quinoline quinones (PQQ), 1, 2-benzoquinones, 1, 4 -Benzoquinones, 1, 2-naphthoquinones, 1, 4-naphthoquinones or 9, 10-anthraquinones or derivatives thereof.

10. The component according to one of claims 1 to 5, in which the electron donor (D) and / or the electron acceptor (A) are charge transfer complexes.

11. The component according to claim 10, wherein the charge transfer complex is a transition metal complex, in particular a Ru (II) -, a Cr (III) -, a Fe (II) -, an Os (II) - or a Co (ll) complex.

12. The component according to one of claims 1 to 5, in which the electron donor (D) is selected from the group fullerene, in particular C60, p-doped fullerene and carotenoid.

13. Component according to one of claims 1 to 5, in which the electron acceptor (A) is selected from the group fullerene, in particular C60, n-doped fullerene and stilbene.

14. Component according to one of the preceding claims, in which the binding partner of the chemical bond of the permanent contact point (s) is selected from the group consisting of amino groups and groups which can be specifically linked thereto, in particular carboxy and hydroxy groups, activated esters, in particular succinimidyl esters, Isothiocyanates, sulfonyl chlorides, aldehydes - thiol groups and groups that can be specifically linked to them, in particular alkyl halides, haloacetamides, maleimides, aziridines and symmetrical disulfides - hydroxy groups and groups that can be specifically linked to them, in particular acyl azides, isocyanates, acyl nitriles and acyl chlorides - aldehydes, ketones and specifically linkable groups - especially hydrazines and aromatic amines.

15. The component according to claim 14, wherein at least one of the binding partners of the chemical bond is provided with a protective group to prevent a link.

16. The component according to one of claims 1 to 13, in which the binding partner of the chemical bond of the permanent contact point (s) is a single-stranded nucleus. is an acid oligomer with a specific sequence, preferably a DNA, RNA or PNA oligonucleotide consisting of 5 to 30 nucleotides.

17. The component according to one of claims 1 to 13, in which the binding partner of the chemical bond of the permanent contact point (s) is a photoactivatable crosslinker, such as aryl azide or benzophenone derivative.

18. Component according to one of the preceding claims, the surface of which is electrically insulating with the exception of the contact points.

19. The component according to claim 18, on the surface of which, with the exception of the contact points, electrically insulating molecular parts are arranged, preferably molecular parts selected from the group of peptides, proteins and cyclodextrins.

20. The component according to one of the preceding claims, in which a charge transfer between the electron donor (D) and the electron acceptor (A) can be varied by external influences, in particular by electromagnetic radiation, temperature, static electrical or magnetic fields, pressure, acceleration or a chemical environment.

21. The component according to one of the preceding claims, which contains, in addition to the electron donor (D) and the electron acceptor (A), at least one further redox-active substance, the further redox-active substance having a contact point for linking to other components, which is a permanent or temporary contact point - forms is.

22. The component as claimed in claim 21, in which the further redox-active substance is arranged in such a way that its electrical potential influences the charge transfer between the electron donor (D) and the electron acceptor (A), in particular in which the charge carrier transfer rate increases, the higher the potential the other redox-active

Substance is, or at which the charge transfer rate decreases, the higher the potential of the further redox-active substance.

23. Molecular electronic assembly comprising two or more components (10, 20, 30) connected to one another via the contact points (SC, SC, SR, SR) according to one of the preceding claims.

24. The assembly according to claim 23, in which a part (SC, SC, SR, SR) of the permanent contact points (SJ.SG.SC, SC, SO, SR, SR.SS) of the components carries mutually associated binding partners, and at least one Part of the components are connected to one another by a chemical reaction associated with binding partners.

25. The assembly as claimed in claim 23 or 24, in which at least some of the components are electrically connected to one another via linear molecules of defined conductivity arranged between their contact points and provided with permanent contact points at both ends.

26. An assembly according to claim 25, in which the linear connecting molecules are selected from the group consisting of linear, unsaturated hydrocarbons, in particular polyacetylenes (CH) x, carbyne Cx, sulfur-nitrogen polymers (SN) x and polypyrroles and phenylazetylenes (oligo- Phenylethynyls), double-stranded nucleic acid oligomers, in particular DNA, RNA or PNA, biological nerve cells,

Carbon nanotubes, silicon nanowires, conductive organic crystals such as fluoranthene, perylene hexafluorophosphate, and other radical cation salts of the arenes.

27. The assembly of claim 25 or 26, wherein at least one of the linear connecting molecules consists essentially of unsaturated hydrocarbons and the electrical resistance is increased by incorporating individual saturated carbon atoms.

28. An assembly according to any one of claims 25 to 27, in which at least one of the linear connecting molecules consists essentially of double-stranded nucleic acid oligomers and whose electrical resistance by the incorporation of base mismatches or sections of single-stranded nucleic acid oligomers is increased.

29. Assembly according to one of claims 25 to 28, in which at least one of the linear connecting molecules is formed by a doped carbon nanotube, the conductivity of which is changed by the incorporation of foreign atoms.

30. Module according to one of claims 23 to 29, which electrically forms an AND, OR, NAND, NOR or EXOR gate, a memory element, in particular a ROM or SRAM, an amplifier or a sensor.

31. Electronic circuit with at least one molecular component according to one of claims 1 to 22, or a molecular electronic assembly according to one of claims 23 to 30, in which at least one component (10, 20, 30) on an electrically conductive surface

(111) is attached, in particular by covalent attachment or specific adsorption.

32. Method for producing an electronic circuit, in which at least one first component is added in solution, wherein a component is a component according to one of claims 1 to 22, a molecular electronic assembly according to one of claims 23 to 30, or a conductive linear Compound molecule comprises

at least one further component is added, the first and the further component each having a permanent contact point with mutually assigned binding partners, so that the first and the further component connect to one another at the assigned contact points in the solution,

- The step of adding further components is repeated, the further component and one of the already connected components each having a permanent contact point with mutually associated binding partners, so that the components are in the solution at the assigned contact points connect until a number of predetermined components are connected, and

- The interconnected components are applied to a conductive surface.

33. A method of manufacturing an electronic circuit, in which

- A conductive surface is provided on which in solution

- at least one first component is added and linked to the conductive surface, - at least one further component is added, the first and the further component each having a permanent contact point with mutually associated binding partners, so that the first and the further component are in contact with the connect assigned contact points in the solution to each other, - the step of adding further components is repeated, the further component and one of the already connected components each having a permanent contact point with mutually assigned binding partners, so that the components are at the assigned contact points in the solution join together until a number of predetermined components are joined together.

34. A method for producing an electronic circuit according to claim 32, in which, before a step of adding a further component, a protective group attached to a permanent contact point of a component of the solution is deprotected, in particular removed.

35. A method for producing an electronic circuit according to claim 33, in which a protective group attached to a permanent contact point of a component attached to the surface is deprotected, in particular removed, before a step of adding a further component.