DE19534494A1 - Transistor useful as electronic switch, amplifier, diode, LED or chemical sensor - Google Patents

Abstract

Transistor has parallel planar source and drain electrodes (1, 2) which are 0.01-100 mu m apart, gate electrode(s) (3) which have the same dimensions as the source and drain electrodes and are placed parallel to and between them, and a layer (4) of discotic columnar liquid crystalline material (I) between the source and drain electrodes with the columnar axis oriented perpendicular to the surface of these electrodes. Also claimed is electronic or electro-optical equipment contg. this transistor.

Description

The present invention relates to new electronic components with transistor function, consisting of

• two parallel planar electrodes ( 1, 2 ) for the current supply (source and drain electrodes), which are spaced from 0.01 to 100 µm apart,
• - One or more grid layers ( 3 ) with control function (gate electrodes), which have the dimensions of the electrodes ( 1 ) and ( 2 ) and are arranged parallel to them between them and
• - A layer ( 4 ) of a material with a discotic-columnar liquid-crystalline order state between the electrodes ( 1 ) and ( 2 ), the orientation of the liquid-crystalline material being such that the axis of the columns is perpendicular to the surfaces of the electrodes ( 1 ) and ( 2 ) is aligned.

Furthermore, the invention relates to the use of the elec tronic components as electronic switching elements, as electronic amplification elements, as diodes and as light emitters diodes and electronic or electro-optical devices, which contain these components.

Numerous planar compounds show liquid-crystalline behavior as an intermediate state during the transition from the solid to the liquid state in certain temperature ranges, whereby disco-columnar order states are formed. In these columnar phases, the charge carrier mobility in the columns is very high and reaches values of up to 10 ^-3 cm² / Vs. In even higher-order columnar phases, the columnar-helical phases, charge carrier mobility of 10 ^-1 cm² / Vs can be observed. This high charge carrier mobility and the fact that the charge transport takes place in the liquid crystalline phase almost undisturbed ("free of traps") makes these compounds interesting for use in semiconductor components. Under disco-columnar liquid-crystalline order state in the sense of the present invention, higher-order columnar order states are also to be understood, such as, for. B. the mentioned columnar helical phases.

Conductive organic compounds have long been known and have also been used in electronic components such as field effect transistors used.

By Yang et al. (Nature 372, 344, (1994) becomes a transistor described as an organic semiconductor material Poly- (2-methoxy-5- (2'-ethylhexyloxy) -1,4-phenylene vinylene contains. This material can be removed by thermal elimination Methoxy groups in a polyphenylene vinylene with extended conjugated double bond system, which electrical charges preferably along the polymer chain manage. However, since the organic semiconductor material in Polymer film does not adopt a preferred orientation, it can anisotropic charge transport behavior of polyphenylene vinylene not fully for the charge transport of electrode too Electrode are used.

JP-A 01 189 965 describes a field effect transistor the disc-shaped aromatic compounds as semiconductor mate rial contains. Due to the geometry of the field effect transistor, at which the semiconductor material as a thin film on a non-conductive Is applied substrate and the electrodes to the side Adjacent film layer can also be a possible one in this case Preferred direction of electric charge transport not for the electrical line from electrode to electrode can be used.

In the older German patent application P 44 29 597.9 the Use of low molecular weight or polymeric organic Compounds with columnar-helical liquid crystalline eigen described in electronic components. Mentioned use in organic transistors like field effect transistors. The relatively long lines also have an effect here paths between the electrodes and the missing preferred direction of the Adverse charge transport from electrode to electrode.

It was therefore an object of the present invention to use transistors Based on organic charge transport compounds to find the overcome these drawbacks and high charge carriers mobility in the direction from electrode to electrode exhibit.

Accordingly, the electronic components mentioned at the beginning found with transistor function.

According to Fig. 1, which shows a cross section through the inventive electronic devices, these devices contain two main electrodes, called source and drain electrodes (1) and (2) to which the ground voltage is applied. (The layer (S) in Fig. 1 is a substrate or carrier layer) switching and amplification processes are achieved by additionally applying a voltage between one of these main electrodes and further electrodes with a control function, the so-called gate electrodes ( 3 ). In the simplest, preferred case, the electronic components contain only one gate electrode. This structure corresponds to the structure of a triode, as is known from triode vacuum tubes. However, there is no vacuum between the electrodes, but a material with a discotic, colournar liquid-crystalline order (layer ( 4 )). This material can either be a liquid-crystalline compound or a mixture of various liquid-crystalline compounds and, if desired, further auxiliaries, or it can be a polymeric material which has resulted from crosslinking reactions from a low-molecular liquid-crystalline compound or mixture. The decisive factor is the occurrence of the discotic-columnar liquid-crystalline order state, which also includes higher order columnar order states such as the columnar helical structures, which are particularly preferred because of their particularly large charge carrier mobility.

For the construction of a triode according to the invention, two different arrangements (A) and (B) are possible, depending on whether the layer ( 4 ) is solid or liquid:

• (A) If the material of the layer ( 4 ) is liquid, the grid electrodes ( 3 ) could not be held in place. It is therefore necessary to support them by means of non-conductive spacers, as illustrated in FIG. 2 in cross section and FIG. 3 in top view. The spacing support elements ( 5 ), the z. B. organic polymers or inorganic insulators such as quartz glass or ceramic, preferably have the same structure as the grid electrodes ( 3 ) between them and are arranged, for example, in parallel bars which are connected by cross pieces, similar to a comb structure, such as it is shown in Figs. (2) and (3). In the free spaces, e.g. B. between the teeth of the comb structure, the material with discotic columnar liquid crystalline order is.

In contrast to the usual field, this arrangement enables effect architecture very small, even electrodes distances because thin layers of insulator and electrodes are technically producible with high precision. Typical Insulator layer thicknesses range between 0.01 and  10 µm. The electrode layers can, for example, by Evaporations are generated and can be even thinner. The short electrode distances are with short charge transport connected and enable very fast switching times, as they are not with comparable field effect arrangements are reachable. The typical dimensions of the comb teeth and the spaces between 0.01 and 100 µm.

• (B) The center electrode ( 3 ) is attached directly between the electrodes ( 1 ) and ( 2 ) without insulator layers and is separated from them by the semiconductor material. This arrangement is possible if the semiconductor material forms a solid film by crosslinking or polymerization. On such a film, the electrode ( 3 ) can be applied and then using conventional methods, for. B. photoresist methods, photo lithography and etching, struc tured in the desired lattice shape. The dimensions and dimensions of this arrangement correspond to those of arrangement (A). The arrangement (B) also enables small electrode spacings with the advantages mentioned above.

Metals and inorganic and organic semiconductors are suitable as electrode materials. Materials with a large work function are preferred for hole transport, e.g. B. gold or ITO (indium tin oxide). ITO also has the advantage that it is transparent and is therefore particularly suitable for phototransistors and light emitting diodes (LEDs). In the case of electron conduction, metals and inorganic and organic semiconductors with a small work function are preferably used, e.g. As aluminum, silver-magnesium alloys or alkali or alkaline earth metals. Suitable material for the gate electrode ( 3 ) is, for example, polyaniline which is protonated with camphorsulfonic acid. Metals such as aluminum, gold or silver can also be used.

Essential for the functionality of the construction elements according to the invention is the orientation of the discotic connections in such a way that the axes of the columns are perpendicular to the surfaces of the electrodes ( 1 ) and ( 2 ). The result of this is that the charge transport which takes place in these phases, preferably in the direction of the column axes, preferably takes place between the electrodes ( 1 ) and ( 2 ) and is only slightly perpendicular to this direction. This orientation can be achieved in different ways.

The easiest way to achieve the desired orientation can be through a coordinated geometry of the semiconductor cells, ie the spaces through the electrode surfaces ( 1 ) and ( 2 ), and laterally z. B. formed by the comb edges of the 3-layer structure described in arrangement (A) can be achieved. Discotic-columnar liquid-crystalline phases usually orient themselves spontaneously in such a way that the axes of the columns are perpendicular to the phase interfaces. In the present case, the desired orientation is therefore often achieved in that the areas of the side edges of the electrodes ( 1 ) and ( 2 ) in the spaces filled with the semiconductor are larger than the areas of the side edges of the electrodes ( 3 ) and the side edges the comb structures described above. This geometry is always present when the space between the electrodes ( 1 ) and ( 2 ) filled with the semiconductor material has a greater length and width than the distance between these electrodes. The spontaneous orientation can be facilitated by annealing, e.g. B. by heating to the isotropic, liquid state and then cooling until reaching the columnar liquid-crystalline phase.

Another way of achieving the desired orientation is to apply orientation layers to the electrode surfaces ( 1 ) and ( 2 ), by means of which the desired orientation is induced in the liquid-crystalline phase. These orientation layers preferably consist of thin films of crosslinked columnar liquid-crystalline compounds, but can also be made of other polymer films, e.g. B. made of polyimides.

Orientation can also be achieved by interaction with the material of the spacing supporting elements ( 5 ), for. B. by interaction of aliphatic side chains of the discotic compounds with a support material which contains similar aliphatic radicals.

In the case of electrically dipolar connections, the orientation can also by applying an electric or magnetic field be effected. Apolar connections can be made by rotating Magnetic fields are oriented. These options exist whenever the liquid crystalline compound or mixture then, preferably in the presence of the electrical or magnetic field, is networked for orientation fix.

As material with discotic columnar liquid crystalline ord voltage state come z. B. Consider connections derived from the following stem bodies: from triphenylene, dibenzo pyrene, benzene, naphthalene, anthracene, phenanthrene, benzophen anthren, Pentahelicen, Perylen, Decacyclen, Truxen, Ruffigallol,  Pyrene, fluorene, indene or from corresponding aromatic systems in which one or more ring carbon atoms pass through Nitrogen, oxygen or sulfur are replaced, as well as by Tri cycloquinazoline, phthalocyanine or porphyrin.

Because of their liquid nature, these compounds are suitable crystalline phase behavior with columnar phases in space particularly mean those with multiple aliphatic groups are substituted.

A preferred group of compounds for use in the Components according to the invention are substituted triphenylenes. Suitable substituted triphenylenes are, for example Compounds of the general formula I.

in which the substituents can be the same or different and have the following meaning:
R is hydrogen, fluorine, chlorine, bromine, iodine, nitro, cyano, formyl, an azo group Ar-N = N-, in which Ar represents an iso- or heteroaromatic radical, an aliphatic group with 1 to 20 C atoms or an araliphatic group with up to 20 C atoms or a group YR¹, in which
Y oxygen, sulfur, -CO-, -CO-O-, -SO₂- or -SO₂-O- and
R¹ represents an aliphatic or an araliphatic group with 1-20 C atoms or hydrogen.

The radicals R and R¹ are alkyl radicals with 1 to 20 carbon atoms in Be like methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, Octyl, nonyl, decyl, dodecyl, tetradecyl and hexadecyl, the Alkyl radicals with 4 to 16 carbon atoms are preferred. Especially before the residues butyl, pentyl, hexyl, heptyl, octyl and nonyl are added and especially the butyl and pentyl radicals.  

For reasons of easier production, the triphenyls are derivatives which carry the same radicals R are preferred, but can be used for Triphenylenes with special properties also a substitution patterns with different residues R may be advantageous.

Azo groups Ar-N = N-, in which Ar is an isoaromatic radical such as phenyl or naphthyl, or a heteroaromatic residue, which is derived from pyrrole, furan, thio phen, pyrazole, imidazole, oxazole, isoxazole, thiazole, isothiazole, Triazole, oxdiazole, thiadiazole, benzofuran, benzthiophene, Benzimidazole, benzoxazole, benzthiazole, benzisothiazole, pyrido thiophene, pyrimidinothiophene, thienothiophene or thienothiazole derives. These residues can in turn z. B. with alkyl, Alkoxy, aryl, aryloxy, cyano or nitro radicals substituted be.

The diazo substituents Ar-N = N- form with the triphenylene ring system is a conjugated π electron system, which is characterized by the Selection of diazo residues can be varied. This gives them Triphenylene interesting optical properties, e.g. B. regarding their absorption or their fluorescence behavior.

Also suitable as radicals R and R¹ are aliphatic groups which have double or triple bonds in their carbon chain, for example ethenyl, propenyl, butenyl, pentenyl, hexenyl, Heptenyl, octenyl, nonenyl, decenyl, dodecenyl, tetradecenyl, Hexadecenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl, hep tinyl, octinyl, noninyl, decinyl, dodecinyl, tetradecinyl or Hexadecinyl, the double or triple conditions preferred are terminal or, in the case of residues R, with the tri phenylene nucleus are conjugated.

As substituents in the aliphatic radicals R and R¹ come in for example the halogens, especially fluorine, the hydroxy group, C₁-C₄ alkoxy groups and oxygen in oxo function into consideration.

The groups YR 1 also include the alkanoyl radicals such as acetyl, Propanoyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, Nonanoyl, Decanoyl, Dodecanoyl, Tetradecanoyl and Hexadecanoyl in Consideration.

Preferred groups YR 1 are alkoxy and alkylthio, particularly preferably those with 4 to 8 carbon atoms.

In addition to the aliphatic groups, R and R¹ also come araliphatic residues. It is particularly worth mentioning this group the benzyl group and for R the benzoyl group, the  in turn can be substituted by various radicals can.

The production of the triphenylene derivatives is, for example, from Kranig et al., Adv. Materials 1, 36 (1990) and from Closs et al., J. Chem. Soc. Perkin Trans. I 829 (1995). More tri Phenylene derivatives can according to the in the German patent application 19 517 208.6 described methods can be obtained.

Depending on the nature of the substituents, different reactions can be considered for the preparation of the triphenylene derivatives:
Halogen-substituted triphenylenes are obtained, for. B. by reacting triphenylene with the elemental halogen.

Formyl and other acyl groups can be converted introduce under the conditions of Friedel-Crafts acylation.

The aliphatic and araliphatic residues on the C₁ atom are unsubstituted, for example, from the Halides under conditions of Friedel-Crafts alkylation hold.

Nitro and azo groups can be known in the Introduce triphenylene ring system.

Triphenylene derivatives with triple bonds in the substituent, the are conjugated to the aromatic system, through Reaction of triphenylene with the corresponding alkyne in counter were producing basic catalysts such as tertiary amines. The use of a catalyst is also advantageous such as palladium chloride / copper diacetate / triphenylphosphine.

Sulfonoxy substituents can be obtained by reacting Hexahydroxytriphenylen with the corresponding sulfonic acids or Sulphonic anhydrides, preferably in the presence of a tertiary Make amines. Alkoxytriphenylenes are obtained, for example by reacting the hydroxy compounds with alkylating agents or according to the known methods of ether synthesis.

Sulfur-linked radicals R₁ can, for. B. by substitution of a Bromotriphenylene can be obtained with appropriate mercaptans. These thioethers can then be oxidized using, for example m-chloroperbenzoic acid to the corresponding sulfonyl compounds be implemented.  

The cyan derivatives are also preferably from the brominated Triphenylenes prepared, e.g. B. by reaction with copper cyanide.

Linked oligomers or polymers can also be used Triphenylenes are used as they are from the older German Registration P 44 22 332.3 are known. These mostly solidify glass well, while preserving the discotically columnar order structure and thus make particularly suitable charge carrier materials represents.

The compounds are generally characterized by liquid crystalline phases in wide temperature ranges and mostly also in the area of room temperature. By mixing different triphenylene derivatives according to the invention or by combination with other liquid crystalline compounds can both Phase width as well as the temperature range of the liquid crystalline state vary.

Triphenylene derivatives which are columnar are particularly preferred can form helical phases. Of these, for example 2,3,6,7,10,11-Hexahexylthiotriphenylen called.

Also suitable are oligomeric triphenylene derivatives, in which several substituted triphenylene residues via one linking central unit are interconnected. As such central units in turn come triphenyls, too polyvalent aliphatic radicals with 2 to 20 carbon atoms or more valuable three- to seven-membered saturated or unsaturated carbocyclic or heterocyclic residues, also benzo can be fused or polyvalent siloxane or cyclo siloxane residues with up to 10 silicon atoms. Such oligomeric liquid crystalline triphenylene derivatives are included described for example in WO 95/02484.

Among the triphenylene derivatives mentioned are those particularly preferred which crosslinkable in the side chains Wear groups. As such networkable groups come For example, consider:

wherein the radicals L are identical or different C₁-C₄ alkyl groups mean. Of these networkable groups are those preferred, which can be radically polymerized, such as for example the olefinically unsaturated groups. The epoxy, Thiiran and aziridine groups as well as the isocyanate and iso thiocyanate groups require reactive auxiliaries for the polymerization bonds such as polyhydric alcohols or amines.

The triphenylene residues contain no reactive groups in the Side chains, so they can also be in a polymer network, which after orientation by polymerization z. B. from Bisacrylaten is built up to be integrated. This too The columnar liquid crystalline is fixed Order condition possible.

Another way of fixing the columnar order state consists in heating the connections and subsequent ones Solidify into the glass state, which is badly crystallizing Connections is possible.

Another preferred group of liquid crystalline charge Transport compounds are the tricycloquinazolines as they are in are described for example in DE-A 43 25 238.  

In addition to the triphenylene derivatives and tricycloquinazoline derivatives the other materials mentioned at the beginning also come as semiconductor material discotic connections into consideration. For the substituents the These connections share the same characteristics and preferences as they were called for the triphenylene derivatives. this applies especially for the networkable groups in the Substituents.

In addition to the liquid-crystalline compounds in the layer ( 4 ), the electronic components according to the invention can also contain auxiliaries with light-absorbing properties or properties which influence the conductivity. Are suitable for. B. compounds with a wide absorption range in the visible spectral range (sensitizers) or compounds that produce a wide absorption spectrum through interaction with the liquid crystal. An example of such compounds is trinitro fluorenone, which can form charge transfer complexes. Other auxiliaries can be compounds which influence the conductivity of the liquid-crystalline material.

The electronic components according to the invention can also contain fluorescent compounds. This fluorescent Compounds can be the liquid crystalline compounds themselves fluorescent dopants can also be added will. As such, all common fluorescent colors come substances in question, being compatible with the liquid crystalline phase and any disturbances in the phase behavior at least in individual cases must be clarified by preliminary tests.

Examples of fluorescent dopants are those from the Series of perylenes, naphthalimides, violanthrones, isoviolanthrones, Pyrene, oxdiazole, bisstyryle, benzoxazole, benztriazole, Coumarins and benzofurans.

In particular, the following fluorescent dyes come as well their derivatives into consideration:

Suitable as fluorescent liquid crystalline compounds for example the following triphenylene derivatives:

The fluorescent or fluorescent-doped semiconductors phases are particularly suitable for electronic components that be referred to as light emitting diodes (LED). In a LED according to the invention can adjust the brightness of the emitted light e.g. B. regulated by the control voltage. A special The advantage of the LEDs according to the invention is the possibility of being large To produce flat components of the type according to the invention, for what inorganic semiconductor elements are hardly suitable. This big flat LEDs can either be controlled uniformly or separated according to micro surface elements, whereby the separate control the micro surface elements by suitably structured elec tread as they are generally known from display technology are possible. There is one for this application Arrangement according to the invention with a plurality of gate electrode layers advantageous because it enables a larger number of To control micro surface elements independently. From such LEDs self-illuminating displays and screens can be manufactured.  

The components according to the invention can also be used as diodes be set. For this purpose, the electrode materials are made out chooses that the one electrode material has a low leakage work for electrons, the material of the counter electrode in contrast, easily injected holes.

In a similar way as as LED, the construction elements according to the invention can also be used as phototransistors. An optical signal is converted into an electrical signal by generating charge carriers. The sensitivity of the gate electrode ( 3 ) can be set to the desired value. The charge carrier can also be generated in an additional generation layer or by means of a doped material.

The flat electrodes ( 1 ) and ( 2 ) can also be structured by conductive and non-conductive areas, as is customary in microchip technology. Defi ned areas of the component according to the invention can thereby be controlled separately and thus integrate a large number of switching or reinforcing elements in a narrow space. In the ideal case, it is possible to control only a few columns of the liquid-crystalline order structure by means of an appropriate electrode structure and in this way to construct quasi-molecular diodes or transistors.

The transistors according to the invention can also be used as elec tronic switching elements by the voltage at the gate electrode - in this case only one is required - releases or completely prevents the current flow between the electrodes ( 1 ) and ( 2 ). The fast switching times due to the small electrode spacings and the associated short charge transport distances are particularly advantageous.

Furthermore, the transistors according to the invention can be used as electronic amplification elements. For this purpose, a basic voltage is applied to the electrodes ( 1 ) and ( 2 ), at which almost no current flows. A slight increase in this voltage due to an additional control potential at the gate electrode ( 3 ) then leads to a current flow which can be regulated very sensitively via the control voltage.

The transistors according to the invention can also be used as chemical sensors, components with polymeric columnar semiconductors being particularly suitable for this use, since they are insoluble and chemically resistant. For this purpose, an electrode ( 1 ) or ( 2 ) without substrate material is applied to the semiconductor layer, so that this electrode directly z. B. can be brought into contact with a solution containing the substance to be detected. This free electrode surface can z. B. coated with receptor molecules. If a ligand binds to a receptor molecule, the electronic properties of the electrode interface change, such as the ionization potential, the work function for charge carriers or the electron affinity. This change in the injection conditions for charge carriers on the electrode influence the current flow between the electrodes ( 1 ) and ( 2 ). The concentration of receptor ligands in the solution can thus be measured by measuring the current flow. This arrangement is particularly suitable for determining charged particles such as ions and protons.

Examples example 1

Gold or aluminum electrodes with a layer thickness of approx. 60 nm were applied to two glass surfaces. With the help of spacers, a cell with an electrode area of 2 mm × 2 mm and a distance of 3 μm was assembled from the glass plates. In this cell was diffused at a temperature of 130 ° C, ie in the isotropic liquid state 2,3,6,7,10,11-hexapentyloxytriphenylene (phase sequence: k 69 ° CD _ho 122 ° C i) and then on cooled to a temperature of 80 ° C. At this temperature, a voltage of -200 to +200 V was applied to the electrodes and the resulting current flow was measured. The current / voltage diagram shows a typical diode behavior with pronounced directional current flow behavior. (see Fig. 4).

Example 2

Analogously to Example 1, a cell with an electrode spacing of 3.7 μm and electrodes made of aluminum or ITO (indium tin oxide) was filled with octapentyloxidibenzopyrene and the current / voltage diagram was recorded at 25 ° C. A typical diode characteristic is also shown here. (see Fig. 5).

Claims (16)

1. Electronic components with transistor function, consisting of

• - Two flat electrodes ( 1 , 2 ) arranged in parallel for the current supply (source and drain electrode), which have a distance of 0.01 to 100 µm from one another,
• - One or more grid layers ( 3 ) with control function (gate electrodes), which have the dimensions of the electrodes ( 1 ) and ( 2 ) and are arranged parallel to them between them and
• - Between the electrodes ( 1 ) and ( 2 ) layer ( 4 ) made of a material with a discotic-columnar liquid-crystalline order state, the orientation of the liquid-crystalline material being such that the axis of the columns is perpendicular to the surfaces of the electrodes ( 1 ) and ( 2 ) is aligned.

2. Electronic components according to claim 1, in which the orientation of the material of the layer ( 4 ) has been effected in that the space filled with this material between the electrodes ( 1 ) and ( 2 ) has a greater length and width than the distance between these electrodes. 3. Electronic components according to claim 1, in which the orientation of the material of the layer ( 4 ) by orientation layers on the electrode surfaces ( 1 ) and / or ( 2 ) or by interaction with the material of the spacing support elements ( 5 ) has been effected . 4. Electronic components according to claim 1, in which the orientation of the material of the layer ( 4 ) has been effected by applying an electrical or magnetic field. 5. Electronic components according to claims 1 to 4 with only one grid layer ( 3 ). 6. Electronic components according to claims 1 to 5, in which the material of the layer ( 4 ) comes from the group of disco columnar liquid crystalline compounds which are derived from triphenylene, dibenzopyrene, phthalocyanine, benzene, naphthalene, anthracene, phenanthrene, benzophenanthrene, Penta helicen, perylene, decacycles, truxes, Ruffigallol, pyrene, fluorene or indene derived or from corresponding aromatic systems in which one or more ring carbon atoms are replaced by nitrogen, oxygen or sulfur, and from tricycloquinazoline or porphyrin. 7. Electronic components according to claims 1 to 6, in which the discotic columnar liquid crystalline Compounds carry reactive groups through which one Networking can be brought about. 8. Electronic components according to claims 1 to 7, in which the layer ( 4 ) contains, in addition to the liquid-crystalline compounds, auxiliaries with light-absorbing properties or properties which influence conductivity. 9. Electronic components according to claims 1 to 8, in which the liquid-crystalline compounds of the layer ( 4 ) are fluorescent compounds or in which the layer ( 4 ) contains fluorescent compounds in addition to the liquid-crystalline compounds. 10. Electronic components according to claims 1 to 8, in which the surface of the electrodes ( 1 ) and / or ( 2 ) is structured by conductive and non-conductive areas. 11. Use of the electronic components in accordance with Claims 1 to 10 as electronic switching elements. 12. Use of the electronic components according to Claims 1 to 10 as electronic reinforcement elements. 13. Use of the electronic components in accordance with Claims 1 to 10 as diodes. 14. Use of the electronic components according to claim 9 as light emitting diodes (LED). 15. Chemical sensors, consisting of an electronic construction element according to claims 1 to 10 and one on the elec trode ( 1 ) applied layer ( 7 ) made of a receptor material, which changes its electronic properties under the influence of the substance to be detected. 16. Electronic or electro-optical devices containing elec tronic components according to claims 1 to 10.