WO2011162199A1

WO2011162199A1 - Method for controlling electric current and apparatus for controlling electric current

Info

Publication number: WO2011162199A1
Application number: PCT/JP2011/064031
Authority: WO
Inventors: 勝一鐘本; 秀展松岡
Original assignee: 公立大学法人大阪市立大学
Priority date: 2010-06-24
Filing date: 2011-06-20
Publication date: 2011-12-29
Also published as: JPWO2011162199A1

Abstract

Disclosed is a method for controlling an electric current, which comprises: a step of preparing an element device (20) that comprises an electrode (22), an electrode (24), and an organic semiconductor layer (26) that is arranged between the electrode (22) and the electrode (24); and a step of controlling an electric current flowing between the electrode (22) and the electrode (24) in association with the electron spin resonance phenomenon of the organic semiconductor layer (26) caused by means of a magnetic field and a microwave. The controlling step comprises a step wherein at least one of the magnetic field, the microwave or the light irradiated upon the organic semiconductor layer (26) is changed.

Description

Current control method and current control apparatus

The present invention relates to a current control method and a current control device.

Since 1988, Fert et al. Discovered the giant magnetoresistive effect on the Fe / Cr artificial lattice, and the applicability of current control using a magnetic field has attracted attention. A magnetoresistive element can use a magnetic field to control the amount of current flowing through the element between certain thresholds to distinguish between two states (typically represented as 0 and 1), for example, It is applied to quantum information processing. In recent years, the magnetoresistive element is used not only for the magnetic sensor and the magnetic head described in Patent Document 1 below, but also for the development of a magnetoresistive memory (Magnetic Resistive Random Access Memory: MRAM).

In general, the characteristics of a magnetoresistive element are expressed by an equation (ρ (0) −ρ (H)) expressed by using an electric resistivity ρ (0) at zero magnetic field and a saturated electric resistivity ρ (H) by applying a magnetic field. ) / Ρ (H). Since the discovery of the Fe / Cr artificial lattice, giant magnetoresistive effects using various metal artificial lattices in which ferromagnetic metals such as Co / Cu, Co / Ag, and Ni / Ag are combined with non-ferromagnetic metals have been discovered.

JP 2000-077743 A

However, although the value of the above formula (ρ (0) −ρ (H)) / ρ (H) exceeds 100% at a very low temperature, it is usually only about 50% at room temperature. Further development to improve the performance is desired. In addition, in order to broaden the applicability of the element, it is desired to develop a current control by another method, not by a magnetic field alone.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel current control method and current control apparatus applicable to various applications.

The current control method according to the present invention includes a step of preparing an element device having a first electrode, a second electrode, and an organic semiconductor layer positioned between the first electrode and the second electrode, and a magnetic field and a microwave. In relation to the electron spin resonance phenomenon of the organic semiconductor layer due to the above, the first electrode and the second electrode are changed by changing at least one of the magnetic field, the microwave and the light applied to the organic semiconductor layer. And controlling the current flowing between them.

In one embodiment, in the changing step, at least one of the magnetic field and the microwave is changed.

In one embodiment, the presence or absence of electron spin resonance in the organic semiconductor layer is changed in the changing step.

In one embodiment, in the preparing step, the element device has an insulating layer provided between at least one of the first electrode and the second electrode and the organic semiconductor layer.

In one embodiment, in the changing step, at least one of the intensity of the magnetic field and the intensity of the microwave is changed.

In one embodiment, in the step of changing, the formation and non-formation of the magnetic field are switched.

In an embodiment, the microwave irradiation and non-irradiation are switched in the changing step.

In one embodiment, in the preparing step, the organic semiconductor layer has a π-type conjugated polymer.

The current control apparatus according to the present invention includes an element device having a first electrode, a second electrode, and an organic semiconductor layer positioned between the first electrode and the second electrode, and a space in which the element device is disposed. A magnetic field forming part for forming a magnetic field on the element device and a microwave irradiating part for irradiating the element device with a microwave, wherein the magnetic field and the electron spin resonance phenomenon of the organic semiconductor layer by the microwave are related to the magnetic field. The current flowing between the first electrode and the second electrode is controlled by changing at least one of the light applied to the microwave and the organic semiconductor layer.

In one embodiment, at least one of the magnetic field forming unit and the microwave irradiation unit changes at least one of the magnetic field and the microwave.

In one embodiment, at least one of the magnetic field forming unit and the microwave irradiation unit changes presence or absence of an electron spin resonance phenomenon in the organic semiconductor layer.

In one embodiment, the element device has an insulating layer provided between at least one of the first electrode and the second electrode and the organic semiconductor layer.

In one embodiment, at least one of the magnetic field forming unit and the microwave irradiation unit changes at least one of the intensity of the magnetic field and the intensity of the microwave.

In one embodiment, the magnetic field forming unit switches between formation and non-formation of the magnetic field.

In one embodiment, the microwave irradiation unit switches between irradiation and non-irradiation of the microwave.

In one embodiment, the organic semiconductor layer has a π-type conjugated polymer.

According to the present invention, novel current control applicable to various uses can be performed.

It is a schematic diagram of an embodiment of a current control device according to the present invention. It is a schematic diagram which shows an example of the element device in the current control apparatus of this embodiment. It is a schematic diagram of the current control device of the present embodiment. It is a schematic diagram which shows an example of the element device in the current control apparatus of this embodiment. It is a schematic diagram which shows an example of the manufacturing method of the element device shown in FIG. It is a graph which shows the change of the current controlled with the current control device of this embodiment. It is a schematic diagram which shows an example of the element device in the current control apparatus of this embodiment. It is a graph which shows the change of the current controlled with the current control device of this embodiment.

Hereinafter, embodiments of a current control method and a current control device according to the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic diagram of a current control device 10 of the present embodiment. The current control apparatus 10 includes an element device 20, a magnetic field forming unit 30, and a microwave irradiation unit 40. The element device 20 is disposed at a place where light is irradiated. For example, the element device 20 is irradiated with sunlight. The magnetic field forming unit 30 forms a magnetic field in the space where the element device 20 is arranged. The microwave irradiation unit 40 irradiates the element device 20 with microwaves. In the current control device 10 of the present embodiment, the magnetic field forming unit 30 forms a magnetic field with a predetermined intensity on the element device 20 and the microwave irradiating unit 40 irradiates the microwave having a predetermined frequency with the element device 20. An electron spin resonance phenomenon occurs in the device 20.

FIG. 2 shows an example of the element device 20 in the current control apparatus 10. The element device 20 includes an electrode 22, an electrode 24, and an organic semiconductor layer 26 positioned between the electrode 22 and the electrode 24. The electrode 22 may be supported by the substrate S. In the following description of the present specification, the electrode 22 and the electrode 24 may be referred to as a first electrode 22 and a second electrode 24, respectively.

When the organic semiconductor layer 26 is irradiated with light, carriers are generated as the organic semiconductor layer 26 absorbs light. For example, carriers are generated when the organic semiconductor layer 26 absorbs visible light and ultraviolet light.

When carriers are generated, if a voltage is applied between the

electrodes

22 and 24, the generated carriers move from the electrode 22 toward the electrode 24 or vice versa. The moving carriers can be taken out as a current flowing between the

electrodes

22 and 24, and such a current is also called a photocurrent. A stacked organic solar cell may be used as the element device 20. For example, a solar cell having an organic thin film semiconductor in which a fullerene derivative as an electron acceptor and a π-type conjugated polymer as an electron donor are combined may be used as the element device 20.

In the current control device 10 shown in FIG. 1, for example, an electromagnet is used as the magnetic field forming unit 30. However, any magnetic field forming unit 30 may be used as long as a magnetic field can be applied. For example, a microwave resonator is used as the microwave irradiation unit 40. The microwave resonance circuit 40 is a cavity resonator surrounded by a wall surface of a conductor such as metal, and is configured so that only an electromagnetic wave having a predetermined frequency satisfying the resonance condition can exist. Here, the element device 20 is disposed between the electromagnets 30 and at the center of the microwave resonator 40.

In the current control device 10 shown in FIG. 1, the magnetic field forming unit 30 and the microwave irradiating unit 40 are integrally configured, and the organic semiconductor layer 26 is operated under resonance conditions determined from the intensity of the magnetic field and the frequency of the microwave. Causes an electron spin resonance phenomenon. In the following description of the present specification, the magnetic field forming unit 30 and the microwave irradiation unit 40 may be collectively referred to as an electron spin resonance apparatus 100. A commercially available apparatus may be used as the electron spin resonance apparatus 100.

Hereinafter, the current control method of this embodiment will be described with reference to FIGS. 1 and 2. First, the element device 20 having the first electrode 22, the second electrode 24, and the organic semiconductor layer 26 is prepared. Next, in relation to the electron spin resonance phenomenon of the organic semiconductor layer 26 by the magnetic field and microwave, the first electrode 22 is changed by changing at least one of the magnetic field, the microwave, and the light applied to the organic semiconductor layer 26. And the current flowing between the second electrode 24 and the second electrode 24 is controlled.

The current control device 10 of the present embodiment controls the current flowing between the electrode 22 and the electrode 24 in association with the electron spin resonance phenomenon caused by the magnetic field and the microwave. When unpaired electrons in the organic semiconductor layer 26 are placed under the influence of a magnetic field having a predetermined strength, they absorb microwaves having a predetermined frequency and transition to a higher energy level. Such a phenomenon is called an electron spin resonance phenomenon. When a strong magnetic field is applied from the magnetic forming unit 30 to the organic semiconductor layer 26 in which a large number of unpaired electrons exist, the spin of the unpaired electrons changes in the direction of the magnetic field. Strictly speaking, some of the spins are parallel to the magnetic field, while some of the spins are antiparallel to the magnetic field. There are many. The energy difference between the former and latter spins changes according to the strength of the magnetic field. In this state, when a microwave having energy necessary for changing the direction from the former to the latter spin is irradiated, electron spin resonance occurs and the incident microwave is absorbed.

For example, when at least one of the magnetic field and the microwave changes from a predetermined state set so as to cause the electron spin phenomenon of the organic semiconductor layer 26 to a state set so as not to cause the electron spin phenomenon, current control is performed. In the device 10, a relatively large current flows between the electrode 22 and the electrode 24. The strength of the magnetic field may be changed from a predetermined value. For example, the strength of the magnetic field may be changed from a predetermined value to zero so that the magnetic field is not formed. Alternatively, the frequency of the microwave may be changed from a predetermined value, or the microwave may be non-irradiated and the intensity of the microwave may be zero.

Strictly speaking, even if the intensity of the magnetic field formed by the magnetic field forming unit 30 and the frequency of the microwave irradiated by the microwave irradiation unit 40 are changed to some extent, the electron spin in the organic semiconductor layer 26 at a certain rate. A phenomenon may occur. For this reason, it is preferable to change the intensity of the magnetic field formed by the magnetic field forming unit 30 and the frequency of the microwave irradiated by the microwave irradiation unit 40 to such an extent that the electron spin phenomenon does not occur. For example, when the intensity of the magnetic field in which the electron spin phenomenon occurs is about 3370 G, the electron spin phenomenon occurs by changing the intensity of the magnetic field by about 10 G (specifically, by making it less than 3360 G or 3380 G or more). Disappear.

In addition, for example, when at least one of the magnetic field and the microwave changes from a state set so as not to cause the electron spin phenomenon of the organic semiconductor layer 26 to a predetermined state set so as to cause the electron spin phenomenon. In the current control device 10, a relatively large current flows between the electrode 22 and the electrode 24. The intensity of the magnetic field may be changed to a predetermined intensity that causes an electron spin phenomenon. For example, the magnetic field may be formed from a non-formation to a predetermined intensity. Alternatively, the frequency of the microwave may be changed to a predetermined frequency that causes an electron spin phenomenon, or the microwave may be changed so as to be irradiated at a predetermined frequency from non-irradiation.

Further, the intensity or wavelength of the light applied to the organic semiconductor layer 26 may be changed in a state where the magnetic field and the microwave are set so as to cause the electron spin phenomenon. Thereby, the current flowing between the electrode 22 and the electrode 24 can be controlled.

As described above, the current control device 10 changes at least one of the light applied to the magnetic field, the microwave, and the organic semiconductor layer 26 in association with the electron spin resonance phenomenon caused by the magnetic field and the microwave. The current flowing between the first electrode 22 and the second electrode 24 can be controlled. For example, when changing at least one of the strength of the magnetic field and the strength and frequency of the microwave, a relatively large current can flow between the electrode 22 and the electrode 24 for each change. Therefore, an alternating current can be generated using electron spin resonance conditions determined from the frequency of the microwave and the magnetic field strength.

In FIG. 1, the strength of the static magnetic field from the magnetic forming unit 30 is indicated as H0, and the strength of the electromagnetic field from the microwave irradiation unit 40 is indicated as H1. When the organic semiconductor layer 26 is irradiated with light in such a state, the microwave from the microwave irradiation unit 40 is satisfied when the resonance condition determined from the value H0 of the static magnetic field and the frequency of the microwave is satisfied. When the intensity and / or frequency of the magnetic field or the intensity (H0) of the magnetic field from the magnetic forming unit 30 is modulated, an alternating current having the modulation frequency can be generated.

For example, by increasing or decreasing the strength of the magnetic field while keeping the frequency of the microwave constant, or by increasing or decreasing the strength of the microwave having a predetermined frequency while keeping the strength of the magnetic field constant. To control the current flowing through. Here, the intensity of the microwave may change in a pulse shape having a certain width, or may change in a sine wave shape. In this case, the frequency of the alternating current generated is determined by the frequency of the intensity modulation of the microwave or magnetic field. Since the magnetic field intensity giving the resonance condition and the microwave frequency are in a proportional relationship, the magnetic field intensity and the microwave frequency can be changed to arbitrary values as long as the resonance condition is satisfied.

For example, the current flowing between the

electrodes

22 and 24 can be controlled by the microwave irradiation unit 40 switching between a state in which the microwave irradiation is performed and a state in which the microwave irradiation is not performed (ON-OFF state). For example, it is possible to switch between a state where an electron spin resonance phenomenon occurs and a state where it does not occur by AM modulation of microwaves, and a current due to the electron spin resonance phenomenon can be generated depending on the switching timing. In this case, a negative spike current immediately after the occurrence of the electron spin resonance phenomenon (that is, immediately after the microwave irradiation is turned on) immediately after the electron spin resonance phenomenon is stopped (that is, immediately after the microwave irradiation is turned off). A spike-like current in the positive direction flows.

Similarly, the current flowing between the

electrodes

22 and 24 due to the electron spin resonance phenomenon can be controlled by switching the state where the magnetic field is not formed (ON-OFF state). In this way, a current can be generated between the electrodes by switching the ON-OFF state of the electron spin resonance phenomenon.

It should be noted that a polaron pair may be involved as a reason for the generation of current by electron spin resonance. A polaron pair is a state in which electrons and holes are weakly bonded between polymer chains, and is an intermediate between excitons and carriers. In the polaron pair, there are singlet (PP _S ) and triplet (PP _T ) forms as well as excitons. Under steady-state conditions, an equilibrium state is established in dissociation and recombination between carriers, polaron pairs, and excitons. By inverting the electron or hole spin of Poraronpea by electron spin resonance, the relationship of the number of PP _S and PP _T collapse from the equilibrium state, the number of carriers is changed, is considered current changes.

In the current control device 10, since the current is controlled using not only the magnetic field but also the microwave, the microwave can be used as a control factor (switch) under the condition that the strength of the magnetic field is constant. Further, when a magnetoresistive element is manufactured using the current control device 10, the value of (ρ (0) −ρ (H)) / ρ (H) indicating one characteristic of the magnetoresistive element is set to 100 at room temperature. %, It can be suitably used for applications requiring a large current difference. As described above, in the current control device 10, it is possible to control the current using not only the magnetic field but also the microwave. Therefore, compared with the case where the current is controlled using only the magnetic field, the current control device 10 has a wider range. Application can be made. In addition, the generated current is generated according to light, and the generated current can be controlled according to the amount of light and the wavelength of light.

In the above description, as an example, the element device 20 (more specifically, the organic semiconductor layer 26) is irradiated with light from the outside of the current control device 10 such as sunlight. It is not limited. The element device 20 (organic semiconductor layer 26) may be irradiated with light emitted from a member in the current control device 10.

FIG. 3 shows a schematic diagram of the current control device 10 of the present embodiment. The current control device 10 shown in FIG. 3 has the same configuration as that of the current control device described above with reference to FIG. 1 except that the light source 50 is further provided, and redundant description is given to avoid redundancy. Omitted. For example, a semiconductor laser may be used as the light source 50. In the current control device 10, the current can be controlled by controlling the light source 50.

In addition, as described above, in the element device 20, a current may flow between the electrode 22 and the electrode 24 by irradiating the organic semiconductor layer 26 with light. Hereinafter, an example of the element device 20 in which a current flows between the electrode 22 and the electrode 24 by light irradiation will be described with reference to FIG.

In the element device 20 shown in FIG. 4, the electrode 22 is a positive electrode and the electrode 24 is a negative electrode. In the element device 20, the organic semiconductor layer 26 includes a buffer layer 26a, an electron donor layer 26b, and an electron acceptor layer 26c. The buffer layer 26a is located between the transparent electrode 22 and the electron donor layer 26b, and improves the charge (hole) injection efficiency into the electron donor layer 26b. The electron donor layer 26b delivers electrons excited by light. The electron acceptor layer 26 c receives the electrons and transfers them to the electrode 24. The electron donor layer 26b and the electron acceptor layer 26c are collectively referred to as a photoelectric conversion layer 26o. Here, the electrode 22 is a transparent electrode, and the electrode 22 is supported by the substrate S. A metal electrode may be used as the electrode 24.

Exciton (exciton) generated by photoexcitation is charge separated at the pn junction at the interface between the electron donor layer 26b and the electron acceptor layer 26c, and electrons are transferred to the electron acceptor layer 26c and holes are transferred to the electron donor layer. Move to 26b. Thereafter, holes can move in the electron donor layer 26b and electrons can move in the electron acceptor layer 26c, and current can be taken out.

The substrate S may be transparent or opaque. However, a transparent substrate is preferably used as the substrate S when the substrate S side is a light receiving surface. In this case, although not particularly limited, a glass substrate such as quartz glass is used as the transparent substrate S. In addition to the glass substrate, a transparent rigid material such as a synthetic quartz plate or a flexible flexible material such as a transparent resin film or an optical resin plate is used as the transparent substrate S. May be.

For example, the transparent electrode 22 may be made of ITO in which tin is added to indium oxide. The material of the transparent electrode 22 is not particularly limited to ITO, but as will be described later, the transparent electrode 22 is preferably formed of a material having a high work function in consideration of the work function of the electrode 24 and the like.

The electrode 24 is not particularly limited as long as it is a conductive material. However, when the transparent electrode 22 is formed from ITO having a relatively high work function, it is preferable to use aluminum having a low work function as the electrode 24.

For example, the buffer layer 26a is made of 3,4-polyethylenedioxythiophene: polystyrene sulfonate (poly (3,4-ethylenedithiothiophene): poly (styrenesulfonate), hereinafter referred to as PEDOT / PSS). PEDOT / PSS exhibits extremely high conductivity and is preferably used as a material for the buffer layer 26a. Alternatively, the buffer layer 26a may be made of starburst amine or CuPc (copper phthalocyanine). Note that the buffer layer 26a may be omitted as necessary.

The electron donor layer 26b is preferably composed of a π-conjugated polymer having conjugated π electrons along the polymer main chain. For example, the electron donor layer 26b is made of poly (2-methoxy-5-ethylhexyoxy-1,4-phenylenevinylene, hereinafter referred to as MEH-PPV). Alternatively, the electron donor layer 26b is formed of poly (3-hexylthiopene) (abbreviation, P3HT) or poly (2-methoxy-5- (3 ′, 7′-dimethylity) -1,1,4-phenylenevinylene) (abbreviation, It may be composed of other π-conjugated polymers such as MDMOPPV).

The electron acceptor layer 26c is made of fullerene (C ₆₀ ) or a fullerene derivative. Fullerene (C ₆₀ ) or fullerene derivatives may exhibit high energy conversion efficiency. Here, fullerene derivatives refer to fullerenes, fullerene derivatives, and mixtures of fullerenes and fullerene derivatives. The fullerene derivative is not particularly limited as long as it is a compound having a fullerene skeleton. In addition, any carbon atom in the fullerene skeleton may be surface-modified with an arbitrary group, and the surface-modifying groups may be bonded to each other to form a ring. Further, the fullerene skeleton units contained in one molecule may be the same or different including the surface modifying group.

Examples of such fullerene derivatives include higher-order fullerenes, surface-modified fullerenes having a surface-modifying group, bucky onions, and fullerene-bonded polymers. Higher order fullerenes include, for example, C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C _{84 and the} like. In the present specification, higher-order fullerenes include not only higher-order fullerenes but also derivatives of higher-order fullerenes. For example, the electron acceptor layer 26c is composed of (6,6) -phenyl-C61-butyric acid methyl ester ((6,6) -phenyl-C61-butylic acid methyl ester (hereinafter referred to as PCBM)) as a fullerene derivative. Is done. Fullerene itself has a low solubility in an organic solvent, and thus is formed by a vacuum deposition method. On the other hand, PCBM can form a solution in an organic solvent into a thin film by spin coating or the like.

In the element device 20, excitons (excitons) generated by photoexcitation are separated by charge at the pn junction at the interface between the fullerene or fullerene derivative (electron acceptor layer 26c) and the π-conjugated polymer (electron donor layer 26b). Move to the electron acceptor layer 26c and holes move to the electron donor layer 26b. Thereafter, holes move through the network of π-conjugated polymer (electron donor layer 26b) and electrons move through the network of fullerene (electron acceptor layer 26c), and are taken out as current.

Hereinafter, an example of the element device 20 shown in FIG. 4 and a manufacturing method thereof will be described with reference to FIG.

First, an electrode 22 containing ITO is formed on the surface of the glass substrate S. Thereafter, a buffer layer 26 a, an electron donor layer 26 b, and an electron acceptor layer 26 c are formed on the electrode 22.

Here, the buffer layer 26a is made of PEDOT / PSS, the electron donor layer 26b is made of MEH-PPV, and the electron acceptor layer 26c is made of PCBM. For example, the buffer layer 26a, the electron donor layer 26b, and the electron acceptor layer 26c are formed in this order by the spin coat method. As a method for applying these materials, for example, a die coating method, a dip coating method, a roll coating method, a bead coating method, a spray coating method, a bar coating method, a gravure coating method, or the like can be used. As described above, the electron acceptor layer 26c may be made of fullerene. In this case, the electron acceptor layer 26c is formed by vacuum deposition.

The electrode 24 is formed using, for example, vacuum deposition. For example, the electrode 24 is formed from aluminum. As a method for forming the electrode 24, in addition to the vacuum deposition method, for example, a PVD method such as a sputtering method or an ion plating method, or a dry coating method such as a CVD method can be employed.

Here, with reference to FIG. 6, the measurement result of the current control apparatus 10 provided with the element device 20 shown in FIG. 4 will be described. FIG. 6 is a graph showing the time change of the current obtained by the current control device 10. In FIG. 6, the horizontal axis indicates time, and the vertical axis indicates the photocurrent generated in the element device 20.

Here, the wavelength of the light applied to the element device 20 is 488 nm, the intensity of the light is 25 mW, and the intensity of the applied magnetic field is 3380G. The frequency of the microwave is about 9.5 GHz. The intensity of the microwave is 50 Hz (period 20 ms), and the intensity is modulated at 0 mW and 200 mW.

As understood from FIG. 6, a DC photocurrent (steady photocurrent) of about 4 nA was obtained at room temperature until the presence or absence of electron spin resonance changed, but the presence or absence of electron spin resonance occurred. Immediately thereafter, spiked photocurrent increases (+11 nA) and decreases (−4 nA) are observed. This spike-like photocurrent has an amplitude value that is 200% or more larger than the DC photocurrent at room temperature.

In FIG. 6, the intensity of the microwave is modulated at a frequency of 50 Hz (period 20 ms), but when this is modulated at about 1 kHz or more, the spike-like current approaches the alternating current waveform of the sine wave. Here, the intensity of light is about 25 mW, but when the irradiation intensity is increased, the alternating photocurrent further increases.

In the above description, when light is applied to the element device 20 (organic semiconductor layer 26), a current flows between the electrode 22 and the electrode 24. However, the present invention is not limited to this. Even if the element device 20 (organic semiconductor layer 26) is irradiated with light, no current may flow between the electrode 22 and the electrode 24.

FIG. 7 shows the structure of the element device 20. The element device 20 shown in FIG. 7 includes, in addition to the

electrodes

22 and 24 and the organic semiconductor layer 26, an insulating layer 23 positioned between the electrode 22 and the organic semiconductor layer 26, and the electrode 24 and the organic semiconductor layer 26. It further has an insulating layer 25 positioned therebetween.

The insulating layers 23 and 25 are made of an insulating resin. As the insulating resin, for example, cycloolefin polymer resin manufactured by Nippon Zeon Co., Ltd. is used. The insulating layers 23 and 25 suppress the current flowing between the electrode 22 and the electrode 24. For example, in the element device 20 shown in FIG. 7, since the insulating

layers

23 and 25 are formed, no steady photocurrent is generated.

In the element device 20 shown in FIG. 7, the organic semiconductor layer 26 may include a π-type conjugated polymer. For example, poly (2-methoxy-5-ethylhexyloxy-1,4-phenylenevinylene, hereinafter referred to as MEH-PPV) is used as the π-type conjugated polymer of the organic semiconductor layer 26. In addition to MEH-PPV, poly (3-hexylopenene) (abbreviation, P3HT), poly (2-methoxy-5- (3 ′, 7′-dimethyloxy))-1,4-phenylenevinylene (abbreviation, MDMOPPV) and C ₆₀ fullerene or the like may be used. When the organic semiconductor layer 26 includes a π-type conjugated polymer, for example, an organic thin film semiconductor that combines a fullerene derivative as an electron acceptor and a π-type conjugated polymer as an electron donor may be used. P3HT absorbs light having a wavelength of 650 μm or less, and MDMOPPV absorbs light having a wavelength of 600 nm or less. C ₆₀ fullerene absorbs light in the visible region and the ultraviolet region.

7, the insulating layer 23 is provided between the transparent electrode 22 and the organic semiconductor layer 26, and the insulating layer 25 is provided between the organic semiconductor layer 26 and the metal electrode 24. The insulating layers 23 and 25 can generate a spike-like alternating current due to a change in the presence or absence of electron spin resonance while no steady photocurrent is generated in the element device 20.

Hereinafter, the reason why the spike current is generated although the insulating

layers

23 and 25 are provided will be described. Usually, when a device having a structure in which an organic semiconductor layer is sandwiched between different electrodes is short-circuited, an internal electric field is generated in the organic semiconductor layer, and the direction in which the photocurrent flows is uniquely determined by the direction of the electric field. Therefore, the phenomenon in which the direction of the photocurrent is reversed by the observed electron spin resonance cannot occur due to a change in the number of carriers. It is considered that the current change caused by electron spin resonance is caused by a displacement current induced by a change in the electric field environment (ie, dielectric constant) in the device. The details of the mechanism by which the internal electric field changes due to electron spin resonance are not clear at present, but the increase or decrease in the recombination amount or dissociation amount of the polaron pair due to spin inversion changes the carrier distribution inside the device, It is thought that the internal electric field changes due to electron spin resonance.

In the element device 20 shown in FIG. 7, the two insulating

layers

23 and 25 are provided on both sides of the organic semiconductor layer 26, but the present invention is not limited to this. Of the insulating

layers

23 and 25, only the insulating layer 23 may be provided, or only the insulating layer 25 may be provided. Thus, the element device 20 may be provided with at least one of the insulating

layers

23 and 25.

Hereinafter, the measurement results when the element device 20 shown in FIG. 7 is used will be described with reference to FIG. FIG. 8 shows a time change spectrum in the vicinity of the peak (that is, the resonance point) of the photocurrent detection ESR signal measured with an oscilloscope. The ON / OFF state of the electron spin resonance phenomenon is realized by microwave AM modulation. Here, in the photocurrent detection ESR, an element device set in an X-band microwave cavity is photoexcited with a semiconductor laser having a wavelength of 473 nm, and the photocurrent I is measured at room temperature in a nitrogen atmosphere. *

8 that when the element device 20 provided with the insulating

layers

23 and 25 is used, a steady photocurrent is not observed by the insulating

layers

23 and 25, while a spike current due to electron spin resonance is observed. Thus, by providing the insulating

layers

23 and 25 between the organic semiconductor layer 26 and the

electrodes

22 and 24, a steady photocurrent is removed, and a spike current is obtained when the presence or absence of electron spin resonance changes. As can be understood from a comparison between FIG. 6 and FIG. 8 performed under the same conditions for the element device 20 in which the insulating layer is not formed, when the element device 20 shown in FIG. No. 10 can sufficiently obtain an alternating current resulting from a change in the presence or absence of electron spin resonance without generating a steady photocurrent, and can improve the performance of the element device 20.

In the above description, the steady photocurrent is suppressed by providing the insulating layer 23 and / or the insulating layer 25. However, the element device 20 is exposed to the atmosphere for a long time without providing the insulating

layers

23 and 25. The steady photocurrent can be suppressed. In this case, the spike current can also be increased.

The current control device 10 can be used as a memory in combination with a magnetic material, similarly to MARM. In the MRAM, when there is information, the magnetic material is magnetized by applying a magnetic field to store the information. When reading the information, the current value (resistance) under magnetization is distinguished from the current value in the absence of a magnetic field to distinguish between the two states. In the current control device 10, since the current can be controlled based on the change of the magnetic field, information can be read through the current. Also, control by microwaves can be performed.

Further, the current control device 10 may be used as a photovoltaic element that can be remotely controlled by microwaves. Alternatively, the current control device 10 can control the current using a microwave or a magnetic field as a switch. For example, the current control device 10 can be used as a switch element by bringing a magnetic body or the like close to the element device 20 in a state where the magnetic field from the magnetic field forming unit 30 is applied. The current control device 10 is used for electronic information processing such as a computer or remote monitoring or communication equipment.

According to the present invention, novel current control applicable to various uses can be performed. The current control device of the present invention is suitably used for manufacturing a switch or a memory.

DESCRIPTION OF SYMBOLS 10 Current control apparatus 20 Element device 22 Electrode 24 Electrode
26 Organic semiconductor layer

26a buffer layer

26b electron donor 26c electron acceptor 26o photoelectric conversion layer 30 magnetic field forming unit 40 microwave irradiation unit

Claims

Preparing an element device having a first electrode, a second electrode, and an organic semiconductor layer located between the first electrode and the second electrode;
In connection with the electron spin resonance phenomenon of the organic semiconductor layer due to the magnetic field and microwave, by changing at least one of the magnetic field, the microwave and the light applied to the organic semiconductor layer, And a step of controlling a current flowing between the second electrodes.
The current control method according to claim 1, wherein, in the changing step, at least one of the magnetic field and the microwave is changed.
3. The current control method according to claim 2, wherein in the changing step, presence or absence of electron spin resonance of the organic semiconductor layer is changed.
4. The device according to claim 1, wherein in the preparing step, the element device has an insulating layer provided between at least one of the first electrode and the second electrode and the organic semiconductor layer. 5. Current control method.
5. The current control method according to claim 1, wherein, in the changing step, at least one of the intensity of the magnetic field and the intensity of the microwave is changed.
6. The current control method according to claim 1, wherein in the changing step, the formation and non-formation of the magnetic field are switched.
The current control method according to any one of claims 1 to 6, wherein, in the changing step, the irradiation and non-irradiation of the microwave are switched.
The current control method according to claim 1, wherein in the step of preparing, the organic semiconductor layer has a π-type conjugated polymer.
An element device having a first electrode, a second electrode, and an organic semiconductor layer located between the first electrode and the second electrode;
A magnetic field forming unit that forms a magnetic field in a space in which the element device is disposed;
A microwave irradiation unit for irradiating the element device with microwaves,
In relation to the electron spin resonance phenomenon of the organic semiconductor layer by the magnetic field and the microwave, the first magnetic field, the microwave, and the light applied to the organic semiconductor layer are changed, thereby changing the first. A current control device in which a current flowing between an electrode and the second electrode is controlled.
The current control device according to claim 9, wherein at least one of the magnetic field forming unit and the microwave irradiation unit changes at least one of the magnetic field and the microwave.
The current control device according to claim 10, wherein at least one of the magnetic field forming unit and the microwave irradiation unit changes presence or absence of an electron spin resonance phenomenon in the organic semiconductor layer.
The current control device according to any one of claims 9 to 11, wherein the element device has an insulating layer provided between at least one of the first electrode and the second electrode and the organic semiconductor layer.
The current control device according to claim 9, wherein at least one of the magnetic field forming unit and the microwave irradiation unit changes at least one of the intensity of the magnetic field and the intensity of the microwave.
The current control device according to claim 9, wherein the magnetic field forming unit switches between formation and non-formation of the magnetic field.
The current control device according to claim 9, wherein the microwave irradiation unit switches between irradiation and non-irradiation of the microwave.