Organic semiconductor element

Abstract

By introducing new concepts into a structure of a conventional organic semiconductor element and without using a conventional ultra thin film, an organic semiconductor element is provided which is more reliable and has higher yield. Further, efficiency is improved particularly in a photoelectronic device using an organic semiconductor. Between an anode and a cathode, there is provided an organic structure including alternately laminated organic thin film layer (functional organic thin film layer) realizing various functions by making an SCLC flow, and a conductive thin film layer (ohmic conductive thin film layer) imbued with a dark conductivity by doping it with an acceptor and a donor, or by the like method.

Claims

1. An electronic device emitting white light, comprising: a substrate; a first electrode over the substrate; a second electrode over the substrate; first through n-th light emitting layers between the first electrode and the second electrode, where n is an integer greater than or equal to 3, wherein a first region comprising an acceptor and an organic compound is provided between a k-th light emitting layer and a (k+1)-th light emitting layer, where k is an integer of 1≤k≤(n−1), and wherein the electronic device emits blue fluorescence and yellow phosphorescence.

2. The electronic device according to claim 1, wherein the organic compound comprises a phenanthroline skeleton.

3. The electronic device according to claim 2, wherein the first region further comprises a donor having an electron attracting group.

4. The electronic device according to claim 3, wherein the electron attracting group is a cyano group.

5. An electronic device emitting white light, comprising: a substrate; a first electrode over the substrate; a second electrode over the substrate; a first functional thin film layer comprising a first hole-transport layer between the first electrode and the second electrode; a second functional thin film layer comprising a second hole-transport layer between the first functional thin film layer and the second electrode; a third functional thin film layer comprising a third hole-transport layer between the second functional thin film layer and the second electrode; a first layer between the first functional thin film layer and the second functional thin film layer; and a second layer between the second functional thin film layer and the third functional thin film layer; wherein the first hole-transport layer, the second hole-transport layer and the third hole-transport layer comprises a first organic compound comprising an amino group, wherein the first layer and the second layer comprises a second organic compound comprising an electron attracting group and, wherein the electronic device emits blue fluorescence and yellow phosphorescence.

6. The electronic device according to claim 5, wherein the first organic compound comprises a biphenyl skeleton.

7. The electronic device according to claim 5, wherein the electron attracting group is a cyano group.

8. The electronic device according to claim 7, wherein the first layer and the second layer further comprises a third organic compound having a phenanthroline skeleton.

9. An organic electroluminescent element emitting white light, comprising: a first electrode; a second electrode; a first functional thin film layer comprising a first hole-transport layer and a first light-emitting layer between the first electrode and the second electrode; a second functional thin film layer comprising a second hole-transport layer and a second light-emitting layer between the first functional thin film layer and the second electrode; a third functional thin film layer comprising a third hole-transport layer and a third light-emitting layer between the second functional thin film layer and the second electrode; a first layer between the first functional thin film layer and the second functional thin film layer; and a second layer between the second functional thin film layer and the third functional thin film layer; wherein the first hole-transport layer, the second hole-transport layer and the third hole-transport layer comprises a first organic compound comprising an amino group, wherein the first layer and the second layer comprises a second organic compound comprising an electron attracting group, wherein the first light-emitting layer and the third light-emitting layer are configured to emit blue fluorescence and wherein the second light-emitting layer is configured to emit yellow phosphorescence.

10. The electronic device according to claim 9, wherein the first organic compound comprises a biphenyl skeleton.

11. The organic electroluminescent element according to claim 9, wherein the electron attracting group is a cyano group.

12. The organic electroluminescent element according to claim 11, wherein the first layer and the second layer further comprises a third organic compound having a phenanthroline skeleton.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the accompanying drawings:

(2) FIG. 1 shows a basic structure of the present invention;

(3) FIGS. 2A and 2B show concepts of the present invention;

(4) FIGS. 3A to 3C show effects produced by the present invention;

(5) FIGS. 4A and 4B illustrate theory behind improvement in electrical current efficiency;

(6) FIG. 5 shows theory behind improvement in the electrical current efficiency;

(7) FIGS. 6A and 6B depict conventional organic EL elements;

(8) FIG. 7 shows an organic EL element according to the present invention;

(9) FIG. 8 shows a specific example of an organic EL element according to the present invention;

(10) FIG. 9 shows a specific example of an organic EL element according to the present invention; and

(11) FIG. 10 shows a specific example of an organic EL element according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) Hereinafter, detailed explanation is made with respect to embodiments of the present invention, using an organic EL element and an organic solar battery as examples. Note that, with respect to the organic EL element, in order to achieve light emission, it is sufficient if at least one of an anode and a cathode is made transparent. However, in accordance with this embodiment mode, description is made of an element structure in which a transparent anode is formed on a substrate to achieve the light from the anode side. In actuality, the present invention may be applied in a structure in which the cathode is formed onto the substrate to achieve the light from the cathode side, and in a structure in which the light is achieved from an opposite side from the substrate, and in a structure in which the light is achieved from both the electrodes on both sides. In the organic solar battery as well, in order to make the battery absorb light, any one side of the element may be made transparent.

(13) First, in the organic EL element, as means for overcoming the poor reliability deriving from the ultra thin film and also for improving the proportion of light emitted in relation to the electrical current (i.e., the electrical current efficiency), in order to achieve a simple device structure, the organic EL element may be connected serially, for example. This will be explained below.

(14) As shown in, FIG. 4A, assume an organic EL element D.sub.1, in which applying a certain electrical voltage V.sub.1 causes an electric current with an electric density J.sub.1 to flow and light is emitted by a light energy per unit surface area L.sub.1 (i.e., photons having certain amounts of energy are emitted, and the light energy is equivalent to the product of that energy multiplied by the number of photons). At this time, a power efficiency φe.sub.1 (this refers to the light emission energy with respect to the electrical energy (electrical power) that was given, and it means the same thing as an “energy conversion rate”) is given in the following formula:
φe.sub.1=L.sub.1/(J.sub.1.Math.V.sub.1)  Formula 3

(15) Next, a case will be considered in which an organic EL element D.sub.2 that is exactly equivalent to the organic EL element D.sub.1 is connected to the organic EL element D.sub.1 serially (See FIG. 4B). Note that, a contact point C.sub.1 connects the two elements D.sub.1 and D.sub.2 together ohmically.

(16) Here, the elements as a whole (i.e., element D.sub.all having the structure consisting of D.sub.1 and D.sub.2 connected to each other) are applied with a voltage V.sub.2 (=2V.sub.1) that is double the voltage that was applied in FIG. 4A. Then, since D.sub.1 and D.sub.2 are equivalent to each other, the voltage V.sub.1 is applied to D.sub.1 and to D.sub.2, respectively, as shown in FIG. 4B, and the shared electrical current density J.sub.1 flows. Therefore, since D.sub.1 and D.sub.2 each emit light with the light energy L.sub.1, double the light energy 2L.sub.1 can be obtained from the elements as a whole D.sub.all.

(17) The power efficiency φe.sub.2 at this time is given in the following formula:
φe.sub.2=2L.sub.1/(J.sub.1.Math.2V.sub.1)=L1/(J.Math.V.sub.1)  Formula 3

(18) As can be understood by comparing the above-mentioned Formula 3 and the above-mentioned Formula 4, there is no difference between FIG. 4A and FIG. 4B in terms of the power efficiency, and the law of energy conservation in which V.sub.1 and J.sub.1 are converted to L.sub.1 is being obeyed. However, the current efficiency appears to increase twofold, i.e., L.sub.1/J.sub.1 is increased to 2L.sub.1/J.sub.1. This has a significant meaning for the organic EL element. That is, by increasing the organic EL elements connected serially and by applying more voltage in proportion to the number of elements that were increased and maintaining the current density at a fixed level, it becomes possible to increase the electrical current efficiency.

(19) Examining this concept more generally, when n number of the entirely equivalent organic EL elements are ohmically connected, it is possible to achieve n times the brightness level by maintaining the current density at a fixed level and increasing the electrical voltage by n times. This property derives from the proportional relationship between the brightness level and the electrical current density level in the organic EL element.

(20) Of course, even in the case where different organic EL elements are connected serially, the brightness level emitted from each of the organic EL elements will be different. However, by significantly increasing the voltage, it becomes possible to extract more brightness than in the case of a single organic EL element. A conceptual diagram of this is shown in FIG. 5.

(21) As shown in FIG. 5, when the different organic EL elements D.sub.1 and D.sub.2 are connected serially and one of the organic EL elements (either D.sub.1 or D.sub.2) is applied with a higher voltage V.sub.1+V.sub.2 than the necessary voltage (either V.sub.1 or V.sub.2) to create the electrical current J.sub.1, a brightness level L.sub.1+L.sub.2 (>L.sub.1, L.sub.2) can be produced with the current J.sub.1.

(22) At this time, by configuring, for example, D.sub.1 as a blue light emitting element and D.sub.2 as a yellow light emitting element, if color mixing can be performed, then a white color light emission will occur. Therefore, this enables a white color emitting element in which the electrical current efficiency is higher, and therefore the longevity of the element is higher than in the conventional art.

(23) As described above, by ohmically connecting the elements serially, the apparent electrical current efficiency is improved and greater brightness can be obtained with a smaller electrical current. This means that it is possible to make the necessary electrical current for emission of the same level of brightness is kept smaller than in the conventional art. Furthermore, as long as a significant electrical voltage can be applied, it is possible to connect however many organic EL elements as may be needed, and the overall film thickness can be made thick.

(24) However, as described above, a problem occurs even in the case where the organic EL elements are simply connected serially. The problem derives from the electrodes for the organic EL elements and from the element structure, which will be explained using FIG. 6. FIG. 6A shows a cross-sectional view of the organic EL element D.sub.1 shown in FIG. 4A, and FIG. 6B shows a cross sectional view of all the elements D.sub.all shown in FIG. 4B, in a schematic manner.

(25) The basic structure (FIG. 6A) of the normal organic EL element is manufactured by providing a transparent electrode 602 onto a substrate 601 (here, the electrode is an anode, and an ITO or the like is generally used for this), a functional organic thin film layer (hereinafter, referred to as an “organic EL layer”) 604 for performing light emission by flowing an electrical current is then formed and a cathode 603 is then provided. With this structure, light can be produced from the transparent electrode (the anode) 602. The cathode 603 may be a cathode which normally employs both a metallic electrode with a low work function, or an electron injecting cathode buffer layer, along with a metallic conductive film (such as aluminum or the like).

(26) When two organic EL elements having the structure described above are connected simply serially (as shown in FIG. 6B), the structure will include a first transparent electrode (cathode) 602a, a first organic EL layer 604a, a first cathode 603a, a second organic EL layer 604b, a second organic EL layer 604b, and a second cathode 603b, which are laminated in this order from the lower side. Then, the light emitted by the second organic EL layer 604b cannot be transmitted through because the first cathode 603a which is metal, and thus the light cannot be taken out of the element. Therefore, it becomes impossible to do such innovations as mixing the light emission from the upper and the lower organic EL elements to produce the white color light.

(27) For example, a technique using transparent ITO cathodes for both the anode and the cathode has also be reported (Reference 6: G. Parthasarathy, P. E. Burrows, V. Khalfin, V. G Kozlov, and S. R. Forrest, “A metal-free cathode for organic semiconductor devices”, J. Appl. Phys., 72, 2138-2140 (1998)). By using this, the first cathode 603a can be made transparent. Therefore, it becomes possible to bring out the light emitted from the second organic EL layer 604b. However, since the ITOs are mainly formed by sputtering, there is a concern that the organic EL layer 604a will suffer damage. Further, the process also becomes cumbersome because the application of the organic EL layer by deposition and the application of the ITO by sputtering have to be repeated.

(28) In order to overcome this problem, a more desirable embodiment has a structure such as shown in FIG. 7, for example, in which the electrical current efficiency can be improved using a concept similar connecting the elements serially to improve the electrical current efficiency, and also the element transparency issue can be cleared without a problem.

(29) FIG. 7 shows a structure in which a first organic EL layer 704a, a first conductive thin film layer 705a, a second organic EL layer 704b, and a cathode 703 are laminated in this order on a transparent electrode (anode) 702 that is provided to a substrate 701. In this structure, by applying a material in which the acceptor or the donor has been applied to the organic semiconductor, the first semiconductor thin film layer 705a can be connected almost ohmically to the organic EL layer (i.e., the hole carrier and the electron carriers can be injected), and, moreover, the transparency can be maintained almost completely. Therefore, the light emission that is generated with the second organic EL layer 703b can be brought out, and the electrical current efficiency can be doubled simply by doubling the electrical voltage.

(30) Moreover, since the entire process becomes consistent (for example, when using low molecular materials, a dry process such as vacuum deposition can be used, and when using high molecular materials, a wet process such as spin coating can be used), the manufacturing process does not become cumbersome.

(31) Note that, FIG. 7 shows the structure in which two of organic EL layers have been provided. However, as described above, as long as a significant amount of electrical voltage may be applied, the structure may be multi-layered (of course, the conductive thin film layer is inserted between each of the organic EL layers). Therefore, the poor reliability of the organic semiconductor element, which is derived from the ultra thin film structure, can be overcome.

(32) The philosophy described above naturally can also be applied in the organic solar battery, which is said to utilize the opposite mechanism from the organic EL element. This will explained as follows.

(33) It is assumed here that there is an organic solar battery S.sub.1 in which a given light energy L.sub.1 generates a photoelectric current with an electrical current density J.sub.1, thus generating an electromotive force V.sub.1. N number of the batteries S.sub.1 are ohmically connected serially, and when a light energy nL.sub.1 is irradiated there, n times the electromotive force (=nV.sub.1) can be obtained if an equivalent light energy nL.sub.1/n=L.sub.1) can be provided to all the n number of solar batteries S.sub.1. In short, if all the organic solar batteries that are connected serially can absorb the light, then the electromotive force increases as a product of the number of batteries.

(34) For example, there is a report that discloses improving the electromotive force by connecting two organic solar batteries serially (Reference 7: Masahiro HIRAMOTO, Minoru SUEZAKI, and Masaaki YOKOYAMA, “Effect of Thin Gold Interstitial-layer on the Photovoltaic Properties of Tandem Organic Solar Cell”, Chemistry Letters, pp. 327-330, 1990). According to Reference 7, by inserting a gold thin film between the two organic solar batteries (i.e., between a front cell and a back cell) an effect of improving the electromotive force generated by the light irradiation is obtained.

(35) However, Reference 7 also structures the gold thin film to have a thickness of 3 nm or less in order to achieve the transmittivity. In other words, the film is structured as an ultra thin film that is thin enough for light to pass through it, designed so that the light will reach the back cell. Moreover, reproducibility becomes problematic when the thickness of the ultra thin film is on the order of several nm.

(36) Such problems can also be resolved by using the present invention. That is, in the organic solar battery structure such as disclosed in Reference 7, the present invention may be applied at the gold thin film portion. By doing this, the present invention can be used as a single organic solar battery that is thicker and more highly efficient than the conventional art, instead of connecting two elements serially.

(37) The basic concepts and structures of the present invention have been described above using the organic EL element and the organic solar battery as examples. The following describes preferred examples of structures of the conductive thin film layer to be used for the present invention. However, the present invention is not limited to these examples.

(38) First, various metallic thin films can be used because they are conductive, which is to say they have multiple carriers. Specifically, Au, Al, Pt, Cu, Ni, etc. are examples that can be used. Note that, when these metals are used for the conductive thin film layer, it is preferable that they be formed as ultra thin films thin enough for visible light to pass through (i.e., several nm to several tens of nm).

(39) Further, various metallic oxide thin films can be used, particularly from the viewpoint of visible light transmittivity. Specific examples include ITO, ZnO, SnO.sub.2, copper oxide, cobalt oxide, zirconium oxide, titanium oxide, niobium oxide, nickel oxide, neodymium oxide, vanadium oxide, bismuth oxide, beryllium aluminum oxide, boron oxide, magnesium oxide, molybdenum oxide, lanthanum oxide, lithium oxide, ruthenium oxide and BeO. Further, compound semiconductor thin films can also be used, including ZnS, ZnSe, GaN, AlGaN, and CdS.

(40) A particular characteristic of the present invention is that the conductive thin film layer can be structured of an organic compound. For example, there is a technique for mixing a p-type organic semiconductor and an n-type organic semiconductor to form the semiconductor thin film layer.

(41) Typical examples of a p-type organic semiconductor include, in addition to CuPc represented by Chem. 1 below, phthalocyanine bound to the other metals or bound to no metals (represented by Chem. 2 below). The following can be also used as the p-type organic semiconductor: TTF (represented by Chem. 3 below); TTT (represented by Chem. 4 below); methylphenothiazine (represented by Chem. 5 below); N-isopropylcarbazole (represented by Chem. 6 below); and the like. Further, a hole transporting material used for organic EL etc., such as TPD (represented by Chem. 7 below), α-NPD (represented by Chem. 8 below), or CBP (represented by Chem. 9 below) may be also applied thereto.

(42) ##STR00001## ##STR00002##

(43) Typical examples of an n-type organic semiconductor include, in addition to F.sub.16-CuPc represented by Chem. 10 below, 3,4,9,10-perylene tetracarboxylic acid derivatives such as PV (represented by Chem. 11 below), Me-PTC (represented by Chem. 12 below), or PTCDA (represented by Chem. 13 below), naphthalenecarboxylic anhydrides (represented by Chem. 14 below), naphthalenecarboxylic diimide (represented by Chem. 15 below), or the like. The following can be also used as the n-type organic semiconductor: TCNQ (represented by Chem. 16 below); TCE (represented by Chem. 17 below); benzoquinone (represented by Chem. 18 below); 2,6-naphthoquinone (represented by Chem. 19 below); DDQ (represented by Chem. 20 below), p-fluoranil (represented by Chem. 21 below); tetrachlorodiphenoquinone (represented by Chem. 22 below); nickelbisdiphenylglyoxime (represented by Chem. 23 below); and the like. Further, an electron transporting material used for the organic EL etc., such as Alg.sub.3 (represented by Chem. 24 below), BCP (represented by Chem. 25 below), or PBD (represented by Chem. 26 below) may be also applied thereto.

(44) ##STR00003## ##STR00004## ##STR00005##

(45) Further, in another preferred technique, an organic compound acceptor (electron acceptor) and an organic compound donor (electron donor) are mixed and a charge-transfer complex is formed to make the conductive thin film layer to create conductivity to serve as the conductive thin film layer. The charge-transfer complex crystallizes easily and is not easy to apply as a film. However, the conductive thin film layer according to the present invention may be formed as a thin layer or in a cluster-shape (as long as the carriers can be injected). Therefore, no significant problems occur.

(46) Representative examples of combinations for the charge-transfer complex include the TTF-TCNQ combination shown in Chem. 27 shown below, and metal/organic acceptors such as K-TCNQ and Cu-TCNQ. Other combinations include [BEDT-TTF]-TCNQ (Chem. 28 below), (Me).sub.2P-C.sub.18TCNQ (Chem. 29 below), BIPA-TCNQ (Chem. 30 below), and Q-TCNQ (Chem. 31 below). Note that, these charge-transfer complex thin films can be applied either as deposited films, spin-coated films, LB film, polymer binder dispersed films, or the like.

(47) ##STR00006## ##STR00007##

(48) Further, as a structural example of a conductive thin-film layer, a technique of doping an acceptor or a donor into an organic semiconductor to apply a dark conductivity thereto is preferably used. An organic compound having a π-conjugate system represented by a conductive polymer etc. may be used for the organic semiconductor. Examples of the conductive polymer include materials put into practical use, such as poly(ethylenedioxythiophene) (abbreviated to PEDOT), polyaniline, or polypyrrole, and in addition thereto, polyphenylene derivatives, polythiophene derivatives, and poly(paraphenylene vinylene) derivatives.

(49) Also, when the acceptor is doped, it is preferable that a p-type material be used for the organic semiconductor. Examples of the p-type organic semiconductor may include those represented by Chems. 1 to 9 as described above. At this time, Lewis acid (strongly acidic dopant) such as FeCl.sub.3 (III), AlCl.sub.3, AlBr.sub.3, AsF.sub.6, or a halogen compound may be used as the acceptor (Lewis acid can function as the acceptor).

(50) Further, in the case where the donor is doped, it is preferable to use an n-type material for the organic semiconductor. Examples of n-type organic semiconductors include the above-mentioned Chems. 10 to 26 and the like. Then, for the donor, alkali metals such as represented by Li, K, Ca, Cs and the like, or a Lewis base such as an alkali earth metal (the Lewis base can function as the donor) may be used.

(51) More preferably, several of the structures described above can be combined to serve as the conductive thin film layer. In other words, for example, on one side or both sides of an inorganic thin film such as the above-mentioned metallic thin film, metallic oxide thin film, or compound semiconductor thin film can be formed with a thin film in which a p-type organic semiconductor is mixed with an n-type organic semiconductor, or the charge-transfer complex thin film, or the doped conductive high molecular thin film, or a p-type organic semiconductor doped with the acceptor, or an n-type organic semiconductor doped with the donor. In such a case, it is effective to use the charge-transfer complex thin film in place of the inorganic thin film.

(52) Further, by layering the n-type organic semiconductor thin film that is doped with the donor and the p-type organic semiconductor thin film that is doped with the acceptor to have these serve as the semiconductor thin film layer, it becomes a functional organic semiconductor layer into which the holes and the electrons can both be injected effectively. Furthermore, a technique is also considered in which the donor doped n-type organic semiconductor thin film and the acceptor doped p-type organic semiconductor thin film or laminated onto one side or both sides of the thin film in which the p-type organic semiconductor thin film and the n-type organic semiconductor thin film are mixed together.

(53) Note that, all the types of the thin film which are given above as structures for the above-mentioned semiconductor thin film layer do not need to be formed in film shapes, but rather they may be also formed as island shapes.

(54) By applying the above-mentioned semiconductor thin film layer in the present invention, it becomes possible to manufacture the organic semiconductor element with high reliability and good yield.

(55) As an example, the organic thin film layer of the present invention can be structured such that light emission is obtained by flowing the electric current, to thereby obtain the organic EL element. Thus, the organic EL element of the present invention is also effective because the efficiency can also be improved.

(56) When used in this way, the structure of the organic thin film layer (i.e., the organic EL layer) may be the organic EL element organic EL layer structure and constitute materials that are generally used. Specifically, many variations are possible such as a laminated structure described in Reference 2 with the hole transporting layer and the electron transporting layer, and a single-layer structure using the high-molecular compound, and the high efficiency element using light emission from the triplet excited state. Further, as described above, the colors from each of the organic EL layers as different emission colors can be mixed as different colors to enable an application as a long-life white color light emission element.

(57) Regarding the anode the organic EL element, if the light is to be made to exit form the anode side, then ITO (indium tin oxide), TZO (indium zinc oxide), and other such transparent conductive inorganic compounds can be often used. An ultra thin film of gold or the like is also possible. If the anode does not have to be transparent (i.e., in the case where the light is made to exit from the cathode side), then a metal/alloy and or a conductive body which does not transmit light but which has a somewhat large work function may be used, such as W, Ti, and TiN.

(58) For the organic EL element cathode, a metal or alloy with a small normal work function such as an alkali metal, alkali earth metal or rare earth metal is used. An alloy including these metallic elements may be used as well. For example, an Mg:Ag alloy, an Al:Li alloy, Ba, Ca, Yb, Er, and the like can be used. Further, in the case where the light is to be made to exit from the cathode side, an ultra thin film made of the metal/alloy may be used.

(59) Further, for example, by using the organic thin film layer according to the present invention as the structure that generates the electromotive force by absorbing the light, the organic solar battery can be obtained. Thus, the organic solar battery of the present invention is effective because it improves efficiency.

(60) When structured in this manner, the structure of the functional organic thin film layer may use the structure and structure materials that are generally used in the functional organic thin film layer of the organic solar battery. A specific example is the laminated structure with the p-type organic semiconductor and the n-type organic semiconductor, such as is described in Reference 3.

EMBODIMENTS

Embodiment 1

(61) In accordance with the present embodiment, a specific example will be given of the organic EL element according to the present invention using the charge-transfer complex as the conductive thin film layer. FIG. 8 shows an element structure of the organic EL element.

(62) First, on a glass substrate 801 on which ITO as an anode 802 is deposited into a film with a thickness of about 100 nm, N—N-bis(3-methylphenyl)-N,N-diphenyl-benzidine (abbreviated to TPD) as the hole transporting material is deposited by 50 nm to obtain a hole transporting layer 804a. Next, tris(8-quinolinolato)aluminum (abbreviated to Alq) as a light emitting material having an electron transporting property is deposited by 50 nm to obtain an electron-transporting and light emitting layer 805a.

(63) A first organic EL layer 810a is formed in the above manner. Thereafter, TTF and TCNQ are codeposited at a ratio of 1:1 as a conductive thin film layer 806, forming a layer with a thickness of 10 nm.

(64) After that, 50 nm of TPD is deposited as a hole transporting layer 804b, and deposited on top of this is 50 nm of Alq, which serves as an electron transporting layer/light emitting layer 805b. Thus, a second organic EL layer 810b is formed.

(65) Finally, as the cathode 803, Mg and Ag are codeposited at an atomic ratio of 10:1, and the cathode 803 is formed to have a thickness of 150 nm, to thereby obtain the organic EL element of the present invention.

Embodiment 2

(66) In accordance with this embodiment, a specific example is shown of an organic EL element of the present invention, in which an organic semiconductor that is the same as used in the organic EL layer is included in the conductive thin film layer, and the acceptor and the donor are doped to make the organic EL element conductive. FIG. 9 shows an example of an element structure of the organic EL element.

(67) First, 50 nm of TPD for serving as the hole transport material is deposited onto a glass substrate 901 which has approximately 100 nm of ITO serving as an anode 902. Next, 50 nm of Alq which serves as the electron transporting light-emission material is deposited, and this serves as an electron transporting layer/light emitting layer 905a.

(68) After a first organic EL layer 910a is formed in this way, 5 nm of a layer 906 is codeposited with the Alq so that the donor TTF constitutes 2 mol %. Then, 5 nm of a layer 907 is codeposited with the TPD so that the acceptor TCNQ constitutes 2 mol %, to serve as a conductive thin film layer 911.

(69) After that, 50 nm of TPD is deposited as a hole transporting layer 904b, and deposited on top of this is 50 nm of Alq, which serves as an electron transporting layer/light emitting layer 905b. Thus, a second organic EL layer 910b is formed.

(70) Finally, as the cathode 903, Mg and Ag are codeposited at an atomic ratio of 10:1, and the cathode 903 is formed to have a thickness of 150 nm, to thereby obtain the organic EL element of the present invention. The element can be manufactured simply by the organic semiconductor in the organic EL layer as the material for structuring the conductive thin film layer, and mixing the donor and acceptor, thus being extremely simple and effective.

Embodiment 3

(71) In accordance with the present embodiment, a specific example is shown of a wet-type organic EL element, in which an electrical light emitting polymer is used for the organic EL layer and the conductive thin film layer is formed of a conductive polymer. FIG. 10 shows an element structure of the organic EL element.

(72) First, onto a glass substrate 1001 on which ITO as an anode 1002 is deposited into a film with a thickness of about 100 mu, a mixed aqueous solution of polyethylene dioxythiophene/polystyrene sulfonic acid (abbreviated to PEDOT/PSS) is applied by spin coating to evaporate moisture, so that a hole injecting layer 1004 is formed with a thickness of 30 nm. Next, poly(2-methoxy-5-(2′-ethyl-hexoxy)-1,4-phenylenevinylene) (abbreviated to MEH-PPV) is deposited into a film with a thickness of 100 nm by spin coating to obtain a light emitting layer 1005a.

(73) A first organic EL layer 1010a is formed in the above manner. Thereafter, a 30 nm film of PEDOT/PSS is applied by spin coating, to serve as a conductive thin film layer 1006.

(74) Then, after that, a 100 nm film of MEH-PPV is applied by spin coating, to serve as a light emitting layer 1005b. Note that, since the conductive thin film layer is made of the same material as the hole injecting layer, this second organic EL layer 1010b does not need a hole injecting layer formed to it. Therefore, in a case where a third and a fourth organic EL layer are to be laminated onto this, a conductive thin film layer PEDOT/PSS and a light-emission layer MEH-PPV can be layered alternately according to extremely simple manipulations.

(75) Finally, 150 nm of Ca is deposited as the cathode. On top of this, 150 nm of Al is deposited as a cap to prevent oxidization of Ca.

Embodiment 4

(76) In accordance with the present invention, a specific example is shown of a organic solar battery of the present invention, in which a mix of the p-type organic semiconductor and the n-type organic semiconductor is applied as the conductive thin film layer.

(77) First, 30 nm of CuPc, which is the p-type organic semiconductor, is deposited onto the glass substrate that has approximately 100 nm of ITO applied onto it as a transparent electrode. Next, 50 nm of PV, which serves as the n-type organic semiconductor, is deposited, and CuPc and PV are used to form a p-n junction in the organic semiconductor. This becomes a first functional organic thin film layer.

(78) After that, CuPc and PV are codeposited at a 1:1 ratio as the conductive thin film layer to have a thickness of 10 nm. Further, 30 nm of CuPc is deposited, and on top of that 50 nm of PV is deposited, whereby creating a second functional organic thin film layer.

(79) Finally, 150 nm of Au is applied as the electrode. The organic solar battery structured as described above is extremely effective because it can realize the present invention simply by ultimately using only two types of organic compounds.

(80) By reducing the present invention to practice, it becomes possible to provide the organic semiconductor element which is highly reliable and has good yield, without having to use the conventional ultra thin film. Further, particularly in the photoelectronic device using the organic semiconductor, the efficiency of the photoelectronic device can be improved.