JP4883898B2 - Electronic device and electronic apparatus using the same - Google Patents

Description

  The present invention relates to an electronic device including an organic molecular layer and an electronic apparatus using the electronic device.

  Conventional electronic devices using inorganic materials utilize bulk physical properties as represented by crystalline silicon. For this reason, if the miniaturization proceeds to the limit, bulk characteristics cannot be obtained, and it becomes difficult to obtain a desired function. On the other hand, an organic material can give a function to one molecule, and can expand them to an element size to exhibit a desired function.

  There are various organic materials based on a carbon skeleton. In particular, conductive organic molecules have been confirmed to exhibit various electrical characteristics derived from their molecular structure, and various organic materials such as thin film transistors, sensors, organic LEDs, capacitors, batteries, biofunctional devices, and lasers are used. Applications to electronic devices have been proposed. By using conductive organic molecules, a conductive layer (for example, a semiconductor layer) can be formed without a vacuum process, and cost and area can be increased.

  However, currently reported organic semiconductors have a problem that carrier mobility is lower than that of inorganic semiconductors, and devices using the organic semiconductors have high driving voltage. Therefore, research has been conducted on improving the carrier mobility of organic semiconductors and reducing the driving voltage of elements using organic semiconductors. In addition, in an electronic device using an organic molecular layer as a conductive layer, improvement in conductivity is a problem.

  A typical example of the conductive organic molecular layer is an organic molecular layer using an organic molecule containing a conjugated π electron system extending in the main chain direction. In this organic molecular layer, carriers move by conduction along a conjugated π electron system extending in the main chain direction and by conduction between molecules. As a method for increasing the mobility of carriers in such conduction, methods have been proposed in which organic molecules are aligned to align the direction of the main chain (for example, Patent Documents 1 and 2). However, a special process is required to orient the organic molecules, which complicates the manufacturing process. In addition, even if the organic molecules are oriented, there is a problem that the mobility of carriers is limited by a high barrier between the molecules.

In order to solve the problem of conduction barrier between organic molecules, a method of forming a network of organic semiconductors through fine particles made of a conductor or semiconductor has been proposed (for example, Patent Document 3). However, in the method of Patent Document 3, when the conductive path is formed only by the fine particles or the organic semiconductor, there is a problem that a short circuit occurs or a desired characteristic cannot be stably obtained. For this reason, in order to stably obtain high characteristics, it is necessary to form a combination of fine particles and an organic semiconductor for each monomolecular layer, and there is a problem that manufacturing is not easy. In addition, when the fine particles are conductors, a structure in which semiconductors with extremely short channels are connected is used. Therefore, when used as a semiconductor layer of a field effect transistor, an off current becomes large and an on / off ratio is low ( There was a problem of about 1 digit).
JP-A-5-275695 JP 7-206599 A JP 2004-88090 A

  The present invention has been made to solve the above-described problems, and an electronic device including an organic molecular layer that can be formed by a simple process without using a special manufacturing method and has high carrier mobility or conductivity. One of the purposes is to provide it. Another object of the present invention is to provide an electronic apparatus using the electronic device of the present invention.

  As a result of studying to achieve the above object, the inventors have provided a terminal group constituting a conjugated π-electron system spreading two-dimensionally or three-dimensionally at the terminal of the main chain, and a metal element is present on the surface of the terminal group. It has been found that an organic molecular layer suitable for an electronic device can be formed by using organic molecules that are not coordinated. The present invention is based on this new finding.

That is, the electronic device of the present invention is an electronic device including a conductive organic molecular layer, and the organic molecular layer includes a main chain constituting a first conjugated π-electron system and at least one of the main chains. An organic molecule having a terminal group bonded to an end as a main component, the terminal group constituting a second conjugated π electron system, and the second conjugated π electron system in a direction orthogonal to the main chain Is larger than the spread of the first conjugated π-electron system in the direction perpendicular to the main chain, and the terminal group does not contain a metal element coordinated so as to be exposed on the surface. Specifically, the first electronic device of the present invention is an electronic device comprising a conductive organic molecular layer,
The organic molecular layer includes, as a main component, an organic molecule having a main chain constituting a first conjugated π-electron system and terminal groups bonded to both ends of the main chain, and the terminal group is in a disc shape The second conjugated π-electron system, the electron cloud of the second conjugated π-electron system spreads two-dimensionally and is orthogonal to the main chain The spread of the electron cloud of the second conjugated π electron system in the direction is larger than the spread of the electron cloud of the first conjugated π electron system in the direction orthogonal to the main chain, and the end group It does not contain a metal element coordinated so as to be exposed, the main chain has a chain length in the range of 12.5 nm to 25 nm, the organic molecular layer is a semiconductor layer, and is in contact with the organic molecular layer An electric field is applied to the source and drain electrodes arranged on the organic molecule layer And function as a field effect transistor.
The second electronic device of the present invention is an electronic device comprising a conductive organic molecular layer, wherein the organic molecular layer comprises a main chain constituting a first conjugated π-electron system, and the main chain An organic molecule having a terminal group bonded to both ends as a main component, the terminal group is a terminal group constituting the second conjugated π-electron system, and a metal element is arranged at the center of the cyclic structure. An electron of the second conjugated π-electron system having a structure of porphyrin that is not coordinated or a structure of phthalocyanine in which a metal element is not coordinated at the center of the cyclic structure and in a direction perpendicular to the main chain The spread of the cloud is larger than the spread of the electron cloud of the first conjugated π electron system in the direction orthogonal to the main chain, the chain length of the main chain is in the range of 12.5 nm to 25 nm, and the organic The molecular layer is a semiconductor layer, and the organic layer Comprising a arranged a source electrode and a drain electrode to contact the child layer, and a gate electrode for applying an electric field to said organic molecule layer, which functions as a field effect transistor.
The third electronic device of the present invention is an electronic device comprising a conductive organic molecular layer, wherein the organic molecular layer comprises a main chain constituting a first conjugated π-electron system, and the main chain An organic molecule having a terminal group bonded to both ends as a main component, the terminal group having a porphyrin structure in which a metal element is not coordinated to the center of the cyclic structure, and the main chain is fluorene Having a skeleton formed by copolymerizing thiophene and bithiophene, the chain length of the main chain is in the range of 12.5 nm to 25 nm, the organic molecular layer is a semiconductor layer, and the organic molecular layer A source electrode and a drain electrode arranged to be in contact with each other and a gate electrode for applying an electric field to the organic molecular layer function as a field effect transistor.
In the following description, the spread of the electron cloud of the conjugated π electron system may be simply expressed as the spread of the conjugated π electron system.

  The electronic apparatus of the present invention includes the electronic device of the present invention.

  In the electronic device of the present invention, the organic molecular layer is formed using organic molecules constituting the first conjugated π electron system and the second conjugated π electron system. In this organic molecular layer, carriers move along the main chain via the first conjugated π-electron system. In addition, since the second conjugated π-electron system exists, charge transfer between molecules is promoted through the second conjugated π-electron system without particularly aligning the molecular axis of the main chain. Therefore, carriers move smoothly to adjacent molecules after moving through the conjugated π-electron system of the main chain. As a result, an organic molecular layer having high mobility or conductivity is formed. Since the organic molecule layer can easily move carriers between molecules even when the organic molecules are not oriented, it is not necessary to orient the organic molecules in a specific direction and can be easily formed.

  Moreover, the terminal group of the organic molecule which comprises this organic molecule layer does not contain the metal element coordinate-bonded so that it may be exposed on the surface. The metal element coordinated so as to be exposed on the surface of the terminal group may be liberated, and the liberated metal element (metal ion) moves in the organic molecular layer by application of an electric field. Therefore, when an organic molecular layer is formed using an organic molecule in which a metal element is coordinated on the surface of the terminal group, the operation of the electronic device becomes unstable, for example, the high-speed operation of the electronic device is hindered. Such an adverse effect is particularly great in the case of polyvalent metal ions. In the present invention, an organic molecular layer is formed using organic molecules in which a metal element is not coordinated on the surface of a terminal group, so that an electronic device having high characteristics can be realized. In addition, since the electronic device of the present invention can use a flexible substrate such as a plastic substrate, a flexible device can be realized.

  Embodiments of the present invention will be described below. In the following description, a specific substance may be exemplified as a substance that exhibits a specific function, but the present invention is not limited to this. In addition, the substances exemplified may be used alone or in combination unless otherwise specified. In the following drawings, hatching may be omitted. Further, in this specification, the “polymer” means a compound obtained by polymerizing a specific compound, and includes a compound having a low molecular weight (an oligomer having a low polymerization degree).

  The electronic device of the present invention includes a conductive organic molecular layer. The organic molecular layer includes an organic molecule having a main chain constituting the first conjugated π-electron system and a terminal group bonded to at least one end of the main chain (hereinafter sometimes referred to as organic molecule A). As the main component. The end group constitutes a second conjugated π-electron system. The spread of the second conjugated π electron system in the direction orthogonal to the chain axis of the main chain is larger than the spread of the first conjugated π electron system in the direction orthogonal to the chain axis of the main chain. The end group does not include a metal element coordinated to be exposed on the surface. The organic molecular layer containing the organic molecule A as a main component is a layer in which carriers move, and functions as a conductive layer or a semiconductor layer.

  The first conjugated π-electron system usually extends throughout the main chain of the organic molecule A. The organic molecule A preferably has terminal groups constituting the second conjugated π-electron system at both ends of the main chain. The presence of the second conjugated π-electron system at both ends of the main chain makes charge transfer between molecules particularly easy.

  The first conjugated π electron system and the second conjugated π electron system are preferably conjugated. The main chain consists of a molecular structure that forms a linear or band-like conjugated π-electron system. For example, thiophene derivatives such as polythiophene and polyalkylthiophene, acetylene molecule derivatives such as polyacetylene and polyphenylacetylene, pyrrole molecule derivatives such as polypyrrole and polyalkylpyrrole, phenylene molecule derivatives such as oligophenylene and polyphenylene, A derivative of a copolymer obtained by combining these molecules, a vinyl group, an ethynyl group, or the like, such as a fluorenebithiophene copolymer, is used.

  The organic molecular layer functions as a conductive layer or a semiconductor layer. This organic molecule layer contains the organic molecule A as one of the main components (content ratio: 50% by mass or more). The organic molecular layer contains, for example, organic molecules A at a ratio of 50% by mass or more (for example, 90% by mass or more). In an example, the organic molecular layer includes only the organic molecule A or only a compound that includes the organic molecule A and the main chain of the organic molecule A. When the organic molecular layer includes a cyclic compound that includes the main chain of the organic molecule A, the organic molecule A and the cyclic compound are the main components of the organic molecular layer. The organic molecular layer may include organic molecules other than the organic molecule A, additives, and the like. In addition, the electronic device of the present invention may include other organic molecular layers.

  In the electronic device of the present invention, the second conjugated π-electron system of the organic molecule A may spread two-dimensionally. Examples of the terminal group constituting the second conjugated π-electron system include a terminal group having a porphyrin structure (including a porphyrin derivative) or a terminal group having a phthalocyanine structure (including a phthalocyanine derivative). . In porphyrin and phthalocyanine, a metal element can be coordinated to the center of the cyclic structure, but the organic molecule of the present invention does not contain such a metal element. In addition, as other terminal groups constituting the second conjugated π-electron system spreading two-dimensionally, terminal groups having an aromatic polycyclic structure, for example, terminal groups having a coronene structure, or terminals having a triphenylene structure are used. A group or the like may be used.

  In the electronic device of the present invention, the second conjugated π-electron system of the organic molecule A may be spread three-dimensionally. Examples of the terminal group constituting such a second conjugated π-electron system include terminal groups (including fullerene derivatives) having a fullerene structure such as C60 and C70. Note that since the metal element enclosed in the fullerene structure is not released to the outside, the metal element may be enclosed in the fullerene structure. In addition, as other terminal groups constituting the second conjugated π-electron system spreading three-dimensionally, terminal groups having an aromatic polycyclic structure having a dish-like shape such as corannulene, and derivatives thereof are used. It may be used.

  In the electronic device of the present invention, the organic molecular layer may further include a cyclic molecule that includes the main chain of the organic molecule A, and the organic molecular layer may include the organic molecule A and the cyclic molecule as main components. In this case, the organic molecular layer contains the organic molecule A and the cyclic molecule in a ratio of 50% by mass or more (for example, 90% by mass or more) in total. According to such a configuration, since the main chain is protected by the encapsulated cyclic molecule, an organic electronic device having high environmental resistance can be obtained. In this case, the charge transfer between the molecules is mainly performed by the end group-end group route. In addition, since the main chain included by the cyclic molecule has increased linearity, the effective mobility of carriers from one end to the other end of the main chain is increased.

  In the electronic device of the present invention, the chain length of the main chain of the organic molecule A may be in the range of 3 nm to 30 nm. By setting the chain length of the main chain within this range, if the chain length of the main chain is less than 3 nm, the rate of conduction along the direction of the main chain that is most easily electrically conductive is reduced. In addition, if the chain length of the main chain exceeds 30 nm, the π electron cloud of the main chain cannot be uniformly distributed over the entire main chain, and a portion having a low electron density is formed. If it exceeds 30 nm, it will be saturated characteristically. On the other hand, when the chain length of the main chain exceeds 30 nm, disadvantages such as difficulty in handling the material (for example, decrease in molecular solubility) increase.

  In the electronic device of the present invention, the organic molecule A may have a side chain bonded to the main chain. In this case, the side chain may constitute a third conjugated π electron system. In the organic molecular layer composed of the organic molecule A, two types of charge transfer paths are conceivable: terminal group-terminal group and terminal group-main chain. If a side chain that does not contain a conjugated π-electron system portion exists in the main chain, the charge transfer between the terminal group and the main chain is inhibited. Therefore, when the organic molecule A has a side chain, the side chain is a conjugated π-electron system. It is preferable to constitute.

  In the electronic device of the present invention, the organic molecular layer mainly composed of the organic molecule A is a semiconductor layer, and an electric field is applied to the organic molecular layer and the source and drain electrodes arranged so as to be in contact with the organic molecular layer. It may be provided with a gate electrode and function as a field effect transistor. In this configuration, since at least a part of the organic molecular layer containing organic molecules A as a main component becomes a channel region, a field effect transistor having high carrier mobility in the channel region can be obtained.

  The active matrix display of the present invention is an active matrix display including a switching element, and the switching element is the electronic device (field effect transistor) of the present invention. According to such a configuration, it is possible to realize a sheet-like or paper-like display with low cost and good characteristics.

  The wireless ID tag of the present invention is a wireless ID tag including a plurality of semiconductor elements, and at least a part of the plurality of semiconductor elements is the electronic device (field effect transistor) of the present invention. According to such a configuration, wireless ID tags that can be attached to objects of various shapes or objects made of various materials are obtained. In addition, a wireless ID tag that can be formed into an arbitrary shape can be realized.

  The portable device of the present invention is a portable device including a plurality of semiconductor elements, and at least a part of the plurality of semiconductor elements is the electronic device (field effect transistor) of the present invention. According to such a configuration, any advantages such as low cost, flexibility, impact resistance, and any shape that can be formed in a portable device such as a portable television, a communication terminal, a PDA, and a portable medical device can be added.

  Examples of embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments. In addition, a part of manufacturing method of the compound demonstrated by the following embodiment is mentioned later. In the following drawings, hatching may be omitted.

(Embodiment 1)
In the first embodiment, a field effect transistor (hereinafter sometimes referred to as “FET”) will be described as an example of the electronic device of the present invention.

  1A to 1D are cross-sectional views schematically showing typical examples of the field effect transistor (thin film transistor: TFT) of the present invention. As shown in FIGS. 1A to 1D, the FET of the present invention has various configurations. Each FET includes a substrate 11, a gate electrode 12, a gate insulating layer 13, a semiconductor layer (organic molecular layer) 14, a source electrode 15, a drain electrode 16, and an electrode modification layer (not shown). The source electrode 15 and the drain electrode 16 are in contact with the semiconductor layer 14. The gate electrode 12 faces the semiconductor layer 14 with the gate insulating layer 13 interposed therebetween.

  In general, the FET 100a in FIG. 1A and the FET 100c in FIG. 1C are called top contact type FETs. Further, the FET 100b in FIG. 1B and the FET 100d in FIG. 1D are called bottom contact type FETs.

  The FET of the present invention may have a structure as shown in FIGS. In the FETs 100e and 100f in FIGS. 2A and 2B, the source electrode 15 and the drain electrode 16 are opposed to each other with the semiconductor layer 14 interposed therebetween. In addition, since the effect of this invention is acquired by the organic molecule which is a main component of an organic molecular layer, there is no limitation in particular about parts other than the organic molecule, as long as the effect of this invention is acquired.

  Hereinafter, the FET 100b in FIG. 1B will be described as an example. As shown in FIG. 1B, a gate electrode 12 is formed on one main surface of the substrate 11, and a gate insulating layer 13 is formed so as to cover the gate electrode 12. The source electrode 15 and the drain electrode 16 are formed on the gate insulating layer 13 at a distance from each other. A semiconductor layer 14 is formed so as to cover the two electrodes and the gate insulating layer 13. The semiconductor layer 14 is composed of the conductive organic molecules described above. Thus, in the FET 100 b, the gate electrode 12, the gate insulating layer 13, the two electrodes, and the semiconductor layer 14 are stacked on the substrate 11.

  Next, the FET 100d shown in FIG. 1D will be described as an example. In the FET 100d, the source electrode 15 and the drain electrode 16 are formed on one main surface of the substrate 11 at a distance from each other. The semiconductor layer 14 composed of the conductive organic molecules described above is formed so as to cover the two electrodes and the substrate 11. The gate insulating layer 13 is formed on the semiconductor layer 14. The gate electrode 12 is formed on the gate insulating layer 13 at a position corresponding to at least a region between the source electrode 15 and the drain electrode 16. As described above, in the FET 100 d, the two electrodes, the semiconductor layer 14, the gate insulating layer 13, and the gate electrode 12 are stacked on the substrate 11.

(Embodiment 2)
In Embodiment 2, an active matrix display, a wireless ID tag, and a portable device will be described as examples of devices including the FET of the present invention described in Embodiment 1.

  As an example of an active matrix display, a display using an organic EL in a display portion will be described. FIG. 3 shows a partially exploded perspective view schematically showing the configuration of the display.

  The display shown in FIG. 3 includes drive circuits 110 arranged in an array on a plastic substrate 111. The drive circuit 110 includes the FET of the present invention and is connected to the pixel electrode. On the drive circuit 110, an organic EL layer 112, a transparent electrode 113, and a protective film 114 are disposed. The organic EL layer 112 has a structure in which a plurality of layers such as an electron transport layer, a light emitting layer, and a hole transport layer are stacked. The source electrode line 125 and the gate electrode line 126 connected to the electrode of each FET are connected to a control circuit (not shown).

  FIG. 4 shows an enlarged view of an example of the drive circuit 110 and its periphery. The structure of the FET shown in FIG. 4 is basically the same as the structure shown in FIG. That is, in the FET shown in FIG. 4, the semiconductor layer 124, the source electrode 125 and the drain electrode 126, the gate insulating layer 123, and the gate electrode 122 are stacked on the substrate. As shown in FIG. 4, the drain electrode 126 is electrically connected to the pixel electrode 127 of the organic EL. An insulating layer 128 is formed at a portion where the gate electrode line 126 to which the gate electrode 122 is connected and the source electrode line 125 to which the source electrode 125 is connected intersect.

  As described above, by forming an active matrix display using the FET as described in the first embodiment, an FET with improved carrier mobility can be realized by a simple process without using a special manufacturing method. . For this reason, according to the present invention, it is possible to realize a sheet-like display having mechanical flexibility and impact resistance, which are functions that are added by using an organic FET, which is inexpensive as a whole display. Further, the display speed (reaction speed) can be improved by improving the carrier mobility of the FET.

  In addition, although this embodiment demonstrated the case where organic EL was used for the display part, this invention is not limited to this. The present invention can be applied to other active matrix type displays including circuits including FETs, and the same effect can be obtained.

  Further, the configuration of the drive circuit unit for driving the pixels is not limited to the configuration shown in this embodiment. For example, a current driving FET and a switching FET for controlling the current driving FET may be combined to drive one pixel. Further, a configuration in which a plurality of FETs are combined may be employed. Further, the FET is not limited to the FET shown in this embodiment, and the same effect can be obtained by using another FET of the present invention.

  Next, the case where the FET of the present invention is applied to a wireless ID tag will be described. A perspective view of an example of a wireless ID tag using the FET of the present invention is schematically shown in FIG. In FIG. 5, illustration of wirings for connecting the antenna unit and the memory IC unit, a matching circuit, and the like is omitted.

  As shown in FIG. 5, the wireless ID tag 130 uses a film-like plastic substrate 131 as a substrate. An antenna unit 132 and a memory IC unit 133 are provided on the substrate 131. Here, the memory IC unit 133 is configured using the FET of the present invention as described in the first embodiment. The wireless ID tag 130 can be attached to a non-flat object such as a candy bag or a drink can by giving an adhesive effect to the back surface of the substrate. Note that a protective film is provided on the surface of the wireless ID tag 130 as necessary.

  Thus, by using the FET of the present invention, wireless ID tags that can be attached to articles of various materials and have various shapes can be obtained. Further, by using the FET of the present invention having high carrier mobility, a wireless ID tag having a high reaction speed and a high communication frequency can be obtained.

  Note that the wireless ID tag of the present invention is not limited to the wireless ID tag shown in FIG. Therefore, there is no limitation on the arrangement and configuration of the antenna unit and the memory IC unit. For example, an ethical circuit may be incorporated in a wireless ID tag.

  In this embodiment, the case where the antenna portion 132 and the memory IC portion 133 are formed on the plastic substrate 131 has been described. However, the present invention is not limited to this embodiment. For example, the antenna portion 172 and the memory IC portion 173 may be formed directly on the object using a method such as ink jet printing. Even in that case, by forming the FET of the present invention, a wireless ID tag including an FET with improved carrier mobility can be manufactured at low cost.

  Next, a portable device including an integrated circuit including the FET of the present invention will be described. Various elements using semiconductor characteristics such as arithmetic elements, memory elements, and switching elements are used in integrated circuits of portable devices. By using the FET of the present invention for at least some of these elements, the portable material has the advantages of organic materials such as excellent mechanical flexibility, impact resistance, environmental resistance when discarded, light weight, and low cost. Equipment can be manufactured.

  As examples of the electronic device of the present invention, three portable devices are shown in FIGS.

  A mobile television 140 shown in FIG. 6 includes a display device 141, a reception device 142, a side switch 143, a front switch 144, an audio output unit 145, an input / output device 146, and a recording media insertion unit 147. The integrated circuit including the FET of the present invention is used as a circuit including elements such as an arithmetic element, a storage element, and a switching element that constitute the portable television 140.

  A communication terminal 150 illustrated in FIG. 7 includes a display device 151, a transmission / reception device 152, an audio output unit 153, a camera unit 154, a folding movable unit 155, an operation switch 156, and an audio input unit 157. The integrated circuit including the FET of the present invention is used as a circuit including elements such as an arithmetic element, a storage element, and a switching element constituting the communication terminal 150.

  A portable medical device 160 illustrated in FIG. 8 includes a display device 161, an operation switch 162, a medical treatment unit 163, and a percutaneous contact unit 164. The portable medical device 160 is carried around, for example, wrapped around an arm 165. The medical treatment unit 163 is a part that processes the biological information obtained from the transcutaneous contact unit 164 and performs medical treatment such as drug administration through the transcutaneous contact unit 164 accordingly. The integrated circuit including the FET of the present invention is used as a circuit including elements such as an arithmetic element, a memory element, and a switching element that constitute the portable medical device 160.

  In addition, although the structure of the portable apparatus to which the FET of the present invention is applied has been described with some examples, the present invention is not limited to these structures. Further, portable devices to which the FET of the present invention can be applied are not limited to the exemplified devices. The FET of the present invention requires characteristics such as PDA terminals, wearable AV devices, portable computers, wristwatch type communication devices, mechanical flexibility, impact resistance, environment resistance when throwing away, light weight, and low cost. The present invention can be suitably applied to the equipment to be used.

(Embodiment 3)
In the first and second embodiments, the FET of the present invention and the device using the same have been described. In Embodiment 3, another electronic device of the present invention will be described.

  As an example of the electronic device of the present invention, a cross-sectional view of a gas ion sensor is schematically shown in FIG. In the sensor element 170 of FIG. 9, the change in the conductivity of the organic conductor layer is detected with high sensitivity by the Si-FET as the change in the gate voltage.

  As shown in FIG. 9, a source electrode 175 and a drain electrode 176 are formed on the surface of the Si substrate 171, and an insulating layer 173 is formed so as to cover them. An organic conductor layer 174 is formed on the insulating layer 173, and a gate electrode 172 is formed on the organic conductor layer 174. When gas or ions are chemisorbed on the detector 177, the conductivity of the organic conductor layer 174 changes, and the gate voltage applied to the Si substrate 171 via the organic conductor layer 174 and the insulating layer 173 changes. The amount of current flowing between the source electrode 175 and the drain electrode 176 changes. By monitoring the change in the amount of current, gas and ions can be detected.

  The organic conductor layer 174 is formed of the organic molecule described in the first embodiment, that is, an organic molecule in which the spread of the conjugated π electron system in the terminal group is larger than the spread of the conjugated π electron system in the main chain. By using such an organic molecule, a conductive layer having high conductivity can be formed, so that the driving voltage of the sensor can be lowered and the sensor can have a long life. Even when a plurality of sensors are formed on the same surface, such as an array sensor, a highly sensitive array sensor can be formed by a simple process without using a special manufacturing method.

  Although the gas ion sensor has been described as an example of the sensor element of the present invention, various sensors such as a humidity sensor, a temperature sensor, an optical sensor, and a pressure sensor can be used as sensors having an organic conductor layer. is there. Both sensors can be sensed by using the change in the physical property value of the organic conductor layer in response to changes in the sensing target, and converting the change in the physical property value into an electrical value such as a current value. It is. Therefore, by applying the present invention to these sensors, the conductivity of the conductor layer can be improved, and a sensor having excellent characteristics can be realized stably.

FIG. 10 schematically shows a cross-sectional view of an example of a capacitor as another example of the electronic device of the present invention. A capacitor 180 shown in FIG. 10 is an aluminum electric field capacitor using Al ₂ O ₃ as a dielectric. The anode 182 is Al, and the dielectric layer 183 made of Al ₂ O ₃ is formed by electrochemically oxidizing the surface of the anode 182. In order to increase the capacity, many pores are formed on the surface of the anode 182 by etching as shown in FIG. 10, and it is difficult to directly form the cathode 181 on the surface of the dielectric layer 183. Therefore, after forming the organic conductor layer 184 as an intermediate layer, the cathode 181 is formed.

  In such a capacitor element, when the resistance between the cathode 181 and the dielectric layer 183 is large, there is a problem that the frequency characteristic of the impedance of the element is lowered. In order to solve such a problem, the organic molecule described in the first embodiment, that is, an organic conductor in which the spread of the conjugated π electron system in the terminal group is larger than the spread of the conjugated π electron system in the main chain is used. Form a layer. As a result, the resistance between the cathode 181 and the dielectric layer 183 can be reduced, and a capacitor element having excellent frequency characteristics can be easily realized.

  In addition, although the aluminum electric field capacitor was demonstrated as an example of the capacitor | condenser of this invention, this invention is applicable also to other capacitors, secondary batteries, etc., such as a tantalum electric field capacitor. By applying the present invention to these electronic devices, the conductivity of the conductor layer can be improved, and capacitors and secondary batteries having excellent characteristics can be realized stably.

  As another example of the electronic device of the present invention, a cross-sectional view of an example of an organic semiconductor laser is schematically shown in FIG. The semiconductor laser 190 in FIG. 11 is a laser called a thick film clad type, and its structure is basically the same as that of an organic LED. That is, a transparent electrode 192, a hole transport layer 193, a light emitting layer 194, an electron transport layer 195, and a metal electrode 196 are sequentially stacked on the glass substrate 191. In order to confine generated photons, the charge transport layers above and below the light emitting layer 194 are used as cladding layers. Therefore, the charge transport layer is thicker than the organic LED.

  In such a laser device, there is a problem that a drive voltage increases due to a thick charge transport layer and a current density decreases accordingly. The present invention is applied to solve such a problem. Specifically, the charge transport layer is formed using the organic molecules described in the first embodiment. According to such a configuration, the conductivity of the charge transport layer can be improved, so that the drive voltage can be reduced and a laser element having excellent characteristics can be easily realized.

  Although the thick film clad type organic semiconductor laser has been described as an example of the laser element of the present invention, the present invention is not limited to this. In other organic semiconductor lasers, the resistance from the electrode to the light emitting layer basically affects the drive voltage. Therefore, by applying the present invention to improve the conductivity of the organic semiconductor layer, an organic semiconductor laser having excellent characteristics can be stably realized.

  As described above, in Embodiment 3, the organic electronic device of the present invention has been described with specific examples, but the present invention is not limited to these. The present invention can be applied to a device including an organic conductor layer. By applying the present invention to these devices, the conductivity of the organic conductor layer can be improved by a simple process without using a special manufacturing method.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  In Example 1, an example in which the FET 100b shown in FIG. 1B is manufactured will be described. In the FET 100 b in Example 1, a film of polyethylene terephthalate (hereinafter sometimes referred to as “PET”) was used as the substrate 11. Further, Ni was used as a material constituting the gate electrode 12. As a material constituting the source electrode 15 and the drain electrode 16, an electrode material mainly composed of Au was used. As a material constituting the gate insulating layer 13, polyvinyl alcohol was used. As a material constituting the semiconductor layer 14, a molecule in which the main chain is an oligothiophene derivative and the terminal is modified with porphyrin is used.

  The chemical formula of the organic material used is shown in FIG. 12 and FIG. 13, and the details of the molecular structure will be described. In the molecule of FIG. 12A, a conjugated π-electron system is formed along the molecular chain by the oligothiophene hexamer of the main chain (hydrogen atoms are not shown; the same applies hereinafter). Furthermore, both ends of the main chain are chemically modified with an end group A1. The terminal group A1 of the molecules of FIGS. 12 (a), 12 (b) and 12 (c) is the porphyrin derivative shown in FIG. In addition, although the organic molecule used in the examples may contain a little oligothiophene in the main chain other than the hexamer, it can be substantially regarded as a hexamer.

Compared to the molecule of FIG. 12 (a), the molecule of FIG. 12 (b) only has an alkyl group (—C ₆ H ₁₃ ) as a side chain bonded to the oligothiophene hexamer portion of the main chain. Is different. The molecule of FIG. 12C is different from the molecule of FIG. 12A only in that a biphenyl group is bonded as a side chain to the oligothiophene hexamer portion of the main chain. Further, as a comparative example, as shown in FIG. 14, a molecule different from the molecule of FIG. 12 (a) only in that the terminal group is an alkyl group (—C ₆ H ₁₃ ) was prepared.

  Below, the manufacturing method of FET100b in a 1st example is demonstrated. First, a gate electrode 12 (thickness 100 nm) made of Ni was formed on a substrate 11 (thickness 100 μm) made of PET by mask vapor deposition. Next, an aqueous solution of polyvinyl alcohol was applied by a spin coating method and then dried to form a gate insulating layer 13 (thickness 500 nm). Subsequently, a source electrode 15 and a drain electrode 16 (each having a thickness of 100 nm) made of Au were formed on the gate insulating layer 13 by mask vapor deposition. The source electrode 15 and the drain electrode 16 were formed so that the channel length was 50 μm and the channel width was 500 μm.

  Next, each molecule shown in FIGS. 12 to 14 was dissolved in chloroform. The obtained solution was applied by spin coating and then dried to form a semiconductor layer 14 (thickness 500 nm). In this way, the FET 100b was produced.

  For the four FETs obtained as described above, the carrier mobility was calculated when the source-drain voltage (Vds) was −5 V (corresponding to the linear region) and −30 V (corresponding to the saturation region). The carrier mobility was calculated from the value obtained by measuring the source-drain current (Ids) when the gate-source voltage (Vgs) was swept from +50 V to -80 V for each Vds. . Table 1 shows the evaluation results of carrier mobility.

  In the molecules (a) to (c) of FIG. 12, the spread of the second conjugated π-electron system (conjugated π-electron system composed of end groups) in the direction perpendicular to the main chain is perpendicular to the main chain. Is larger than the spread of the first conjugated π-electron system (conjugated π-electron system constituted by the main chain). When the semiconductor layer 14 was formed using such molecules, carrier mobility was greatly improved as shown in Table 1. In addition, when a side chain was introduced into the main chain, a higher mobility was obtained for the biphenyl group than for an alkyl group having no conjugated π electron system.

  In the FET of the present invention, it was possible to achieve both a high on / off ratio (4 digits or more) and a high carrier mobility. On the other hand, in the sample of the comparative example, both cannot be made compatible. Similar results were obtained for the FETs in Table 2 described later.

  In this example, an example in which a semiconductor layer is formed using materials with different main chain lengths is shown. The structure and manufacturing method of the FET of the second example are the same as those of the first example, except that the material of the semiconductor layer is different.

  The general formula of the organic material used in the second example is shown in FIG. 15, and the details of the molecular structure will be described. The molecule of FIG. 15A includes a fluorene derivative and bithiophene copolymer as a main chain. Then, both ends of the main chain are chemically modified with porphyrin shown in FIG. In Example 2, the number of repeating main chain portions (n in the general formula in FIG. 15A) was 1, 2, 4, 8, 16, 20, 32, unlimited.

  The carrier mobility was evaluated in the same manner as in Example 1 for the FET using the above material as the semiconductor layer. FIG. 16 shows the relationship between the molecular chain length of the main chain portion of the organic molecules used in the semiconductor layer and the measured carrier mobility. As shown in FIG. 16, the molecular chain length of the main chain is preferably in the range of 3 nm to 30 nm, and more preferably in the range of 12.5 nm to 25 nm.

  Example 3 shows an example in which a molecule having a different end group from the molecule used in Examples 1 and 2 is used. The configuration and manufacturing method of the FET of Example 3 are the same as those of Example 1 except that the material of the semiconductor layer is different.

  The molecule used in Example 3 has a main chain composed of the oligothiophene hexamer shown in FIG. 12 (a) as in the molecule of FIG. 12 (a), but the terminal groups bonded to both ends thereof are different. . The terminal groups used in Example 3 are shown in FIGS. FIGS. 17A to 17C show examples of end groups having a disk-like aromatic polycyclic part (conjugated π electron system). FIG. 18 shows a terminal group using fullerene (C60) as an example of a terminal group having a spherical aromatic polycyclic part (conjugated π electron system).

  Regarding the FET using the semiconductor layer made of the material as described above, the carrier mobility was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results of carrier mobility. Comparative sample 2 is an FET using the organic molecule of FIG.

  In the molecules shown in FIGS. 17 and 18, the spread of the second conjugated π-electron system (conjugated π-electron system composed of end groups) in the direction orthogonal to the main chain is the first in the direction orthogonal to the main chain. This is larger than the spread of the conjugated π-electron system (conjugated π-electron system constituted by the main chain). When the semiconductor layer 14 is formed using the molecules shown in FIGS. 17 and 18 in which the conjugated π-electron system of the end group spreads two-dimensionally or three-dimensionally, as shown in Table 2, the carrier mobility is greatly increased. Improved.

  In Example 4, an example in which the FET 100d shown in FIG. 1D is manufactured will be described. In Example 4, a PET film was used as the substrate 11. Ni was used as a material constituting the gate electrode. As a material constituting the source electrode 15 and the drain electrode 16, an electrode material mainly composed of Au was used. As a material constituting the gate insulating layer 13, polyvinyl phenol was used. Further, as a material constituting the semiconductor layer 14, a molecule in which a main chain is a fluorene bithiophene copolymer included by a cyclodextrin of a cyclic molecule and a terminal of the main chain is modified with porphyrin is used.

  First, a cyclic molecule that includes a molecular chain of the main chain will be described with reference to FIG. The cyclodextrin represented by the general formula in FIG. 19A is a cyclic oligomer of glucose, and the size of the ring changes depending on the number of glucose. Typical cyclodextrins include α-cyclodextrin with n = 4, β-cyclodextrin with n = 5, and γ-cyclodextrin with n = 6. From cyclodextrins having different ring sizes, a suitable one can be selected according to the size of the molecule to be included. In the following figures, cyclodextrin may be represented using a schematic diagram as shown in FIG.

  The chemical formula of the organic material used as the material of the semiconductor layer is shown in FIG. The main chain of the molecule in FIG. 20 is a copolymer of fluorene and bithiophene. The number of repeats of the main chain portion was 8. Both ends of the main chain are chemically modified with porphyrin shown in FIG. The bithiophene portion of the main chain is included by cyclodextrin (in this example, β-cyclodextrin), which is a cyclic molecule, as shown in the figure. A molecule not included in cyclodextrin, that is, a molecule shown in FIG. 15 was also prepared.

  A method for manufacturing the FET 100d in this embodiment will be described below. First, a source electrode 15 and a drain electrode 16 (each having a thickness of 100 nm) made of Au were formed on a substrate 11 (thickness: 100 μm) made of PET by mask vapor deposition. These electrodes were formed so that the channel length was 50 μm and the channel width was 500 μm. Next, the semiconductor layer 14 (thickness 250 nm) was formed by applying the organic molecule aqueous solution of FIG. 15 or FIG. 20 by spin coating and then drying. Subsequently, a solution obtained by dissolving polyvinyl phenol in propylene glycol monomethyl ether acetate (PGMEA) was applied by a spin coating method and then dried to form a gate insulating film 13 (thickness 500 nm). Thereafter, a gate electrode 12 (thickness: 100 nm) made of Ni was formed by mask vapor deposition. In this way, an FET 100d was produced.

  The two types of FETs obtained as described above were evaluated for deterioration due to DC load of carrier mobility when the source-drain voltage (Vds) was −30V. The DC load was applied by applying −40 V to the gate electrode with the source and drain short-circuited to ground. The carrier mobility was calculated from a value obtained by measuring Ids when Vgs was swept from +50 V to −80 V in a state where Vds = −30 V was fixed. After performing the measurement for the carrier mobility evaluation as described above, the cycle of applying the DC load again and performing the measurement for the carrier mobility evaluation again was repeated. FIG. 21 shows the relationship between DC load time and carrier mobility degradation. Note that the horizontal axis in FIG. 21 indicates the accumulated time of the DC load time.

  As shown in FIG. 21, an FET using a molecule in which the main chain is encapsulated by a cyclic molecule as a material for the semiconductor layer (with CD coating) is an FET using a molecule not encapsulated (without CD coating). Compared with, the initial carrier mobility was slightly inferior, but the deterioration with respect to the DC load was greatly reduced.

The organic molecule A used in the present invention may be a commercially available one or may be synthesized by a known method. In the case of synthesis, for example, a molecule represented by (HO) ₂ B-main chain-B (OH) ₂ and a molecule in which an iodine group is bonded to the terminal group (I-terminal group) are subjected to a Suzuki coupling reaction. Synthesis is possible by reacting.

  The embodiments of the present invention have been described above with examples. However, the present invention is not limited to the above-described embodiments, and can be applied to other embodiments based on the technical idea of the present invention.

  The present invention can be applied to an electronic device including a conductive layer or a semiconductor layer formed by organic molecules. In addition, the present invention can be applied to various devices including such an electronic device.

It is sectional drawing which shows the example of FET of this invention typically. It is sectional drawing which shows the other example of FET of this invention typically. 1 is a partially exploded perspective view schematically showing an example of an active matrix display of the present invention. FIG. 3 is a perspective view schematically showing a drive circuit of the display of the present invention and a configuration around it. It is a perspective view which shows typically the structure of an example of the wireless ID tag of this invention. It is a perspective view which shows typically the structure of an example of the portable television of this invention. It is a perspective view which shows typically the structure of an example of the communication terminal of this invention. It is a perspective view which shows typically an example of the portable medical device of this invention. It is sectional drawing which shows typically the structure of an example of the sensor element of this invention. It is sectional drawing which shows typically the structure of an example of the capacitor | condenser of this invention. It is sectional drawing which shows typically the structure of an example of the laser of this invention. (A), (b) and (c) are chemical formulas showing the organic molecules used in the examples. 13 is a chemical formula showing a structure of a terminal group of the organic molecule shown in FIG. It is a chemical formula which shows the organic molecule used by the comparative example. (A) is a chemical formula which shows the organic molecule used in the Example, (b) is a chemical formula which shows the terminal group of the molecule | numerator of (a). It is a figure which shows the relationship between the chain length of the principal chain of an organic molecule | numerator, and carrier mobility about an example of FET of this invention. (A), (b) and (c) are chemical formulas showing the end groups of the organic molecules used in the examples. It is a chemical formula which shows the terminal group of the organic molecule used in the Example. (A) is a chemical formula of a cyclodextrin, (b) is a perspective view which shows typically the shape of a cyclodextrin. It is a chemical formula which shows the organic molecule used in the Example of this invention. It is a figure which shows the behavior of deterioration of the carrier mobility in a DC load test about an example of FET of this invention.

Explanation of symbols

11 Substrate 12 Gate electrode 13 Gate insulating layer 14 Semiconductor layer (organic molecular layer)
15 Source electrode 16 Drain electrode 100a-d FET
DESCRIPTION OF SYMBOLS 110 FET drive circuit 130 Wireless ID tag 140 Portable television 150 Communication terminal 160 Portable medical device 170 Sensor element 174, 184 Organic conductor layer (organic molecular layer)
180 condenser 190 laser

Claims (8)

An electronic device comprising a conductive organic molecular layer,
The organic molecular layer includes, as a main component, an organic molecule comprising a main chain constituting a first conjugated π-electron system and terminal groups bonded to both ends of the main chain,
The terminal group has a disk-like aromatic polycyclic portion and constitutes a second conjugated π-electron system;
The electron cloud of the second conjugated π-electron system spreads two-dimensionally;
The spread of the electron cloud of the second conjugated π electron system in the direction orthogonal to the main chain is larger than the spread of the electron cloud of the first conjugated π electron system in the direction orthogonal to the main chain,
Said end groups is free of coordination bond with a metal element so as to be exposed on its surface,
The chain length of the main chain is in the range of 12.5 nm to 25 nm,
The organic molecular layer is a semiconductor layer, and includes a source electrode and a drain electrode arranged to contact the organic molecular layer, and a gate electrode that applies an electric field to the organic molecular layer,
An electronic device that functions as a field effect transistor . An electronic device comprising a conductive organic molecular layer,
The organic molecular layer includes, as a main component, an organic molecule comprising a main chain constituting a first conjugated π-electron system and terminal groups bonded to both ends of the main chain,
The terminal group is a terminal group constituting the second conjugated π-electron system, and the structure of porphyrin in which the metal element is not coordinated to the center of the cyclic structure, or the metal element is at the center of the cyclic structure. It has a structure of phthalocyanine that is not coordinated,
The spread of the electron cloud of the second conjugated π electron system in the direction orthogonal to the main chain is larger than the spread of the electron cloud of the first conjugated π electron system in the direction orthogonal to the main chain,
The chain length of the main chain is in the range of 12.5 nm to 25 nm,
The organic molecular layer is a semiconductor layer, and includes a source electrode and a drain electrode arranged to contact the organic molecular layer, and a gate electrode that applies an electric field to the organic molecular layer,
An electronic device that functions as a field effect transistor . An electronic device comprising a conductive organic molecular layer,
The organic molecular layer includes, as a main component, an organic molecule comprising a main chain constituting a first conjugated π-electron system and terminal groups bonded to both ends of the main chain,
The terminal group has a porphyrin structure in which a metal element is not coordinated to the center of the cyclic structure,
The main chain has a skeleton formed by copolymerizing fluorene and bithiophene,
The chain length of the main chain is in the range of 12.5 nm to 25 nm,
The organic molecular layer is a semiconductor layer, and includes a source electrode and a drain electrode arranged to contact the organic molecular layer, and a gate electrode that applies an electric field to the organic molecular layer,
An electronic device that functions as a field effect transistor . The organic molecular layer further includes a cyclic molecule that includes the main chain;
The electronic device according to any one of claims 1 to 3 , wherein the organic molecular layer includes the organic molecule and the cyclic molecule as main components. The organic molecule has a side chain bonded to the main chain,
The electronic device according to claim 1 , wherein the side chain constitutes a third conjugated π-electron system. An active matrix display comprising a switching element,
An active matrix type display, wherein the switching element is the electronic device according to claim 1 . A wireless ID tag including a plurality of semiconductor elements,
The wireless ID tag whose at least one part of these semiconductor elements is an electronic device of any one of Claims 1-5 . A portable device including a plurality of semiconductor elements,
A portable device in which at least a part of the plurality of semiconductor elements is the electronic device according to claim 1 .

Images