JP4439986B2 - Method for manufacturing electroluminescent element - Google Patents

Description

  The present invention relates to a method for manufacturing an electroluminescent element having an electroluminescent layer between a pair of electrodes.

  The electroluminescent element comprises an electroluminescent layer sandwiched between a pair of electrodes (anode and cathode), and the light emission mechanism is such that holes injected from the anode when a voltage is applied between both electrodes, It is said that electrons injected from the cathode recombine at the emission center in the electroluminescent layer to form molecular excitons, and emit energy when the molecular excitons return to the ground state.

  A low molecular material or a high molecular material can be used for the electroluminescent layer in this electroluminescent element, and the film formation method includes vapor deposition (including vacuum vapor deposition), spin coating, ink jet, Examples include a dip method and an electric field polymerization method.

  These film forming methods can be appropriately selected depending on the properties of the material and the shape of the film to be formed. For example, as a film forming method used for patterning a film made of a polymer material, electrolytic weight is used. Legal methods are used (for example, see Patent Document 1).

  However, in the current field polymerization method, the flatness of the film surface to be formed cannot be obtained sufficiently.

  Usually, since the electroluminescent layer used for the electroluminescent element is formed with a film thickness of about 1 to 100 nm, the flatness of the surface of the formed film is greatly affected by the element characteristics such as the light emission characteristics and the lifetime of the electroluminescent elements. It will have an effect.

JP-A-9-97679

  Accordingly, the present invention provides a method for producing an electroluminescent device having excellent device characteristics such as light emission characteristics and lifetime by forming a thin film with good controllability.

  In order to solve the above-mentioned problems, the inventors of the present invention applied the current density applied to the electrode during the electric field polymerization and the current flow time within a predetermined range to apply the current to the surface of the electrolytic polymerization film. It has been found that the electropolymerized film can be uniformly formed on the electrode surface, particularly when thinning is required.

Therefore, the configuration of the present invention is as follows:
A method of producing an electroluminescent layer using an electrochemical method between a pair of electrodes,
The current density applied to the first electrode and ^{0.4mA / cm 2 ~1.5mA / cm 2} , and as 0.8sec~3.0sec time to flow a current, to form the electroluminescent layer This is a feature of a method for manufacturing an electroluminescent element.

Furthermore, in the present invention, since the film formability is improved particularly when the electrolytic polymerized film is thinned, the electrolytic polymerized film is formed by controlling the total charge amount per unit area in the first electrode. The film thickness is controlled. That is, in the present invention, in addition to the above configuration, the total charge amount per unit area in the first electrode is set to 1.0 mC / cm ^{2 to} 1.2 mC / cm ² , thereby reducing the thickness of the electrolytic polymer film. It is characterized by that.

  In each of the above structures, any of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer can be formed as an electroluminescent layer formed by an electrochemical method. However, this is a method particularly suitable for forming a hole injection layer in order to realize a thin film with good controllability.

  In each of the above structures, the material for forming the electroluminescent layer by an electrochemical method is any of pyrrole, indole, thiophene, 3,4-ethylenedioxythiophene, benzene, naphthalene, azulene, aniline, or phenylene oxide. Or one can be used.

  As shown in the present invention, in the formation of an electroluminescent layer using an electrolytic polymerization method, a thin film can be formed with better controllability by performing the current density and polymerization time within a predetermined range. An electroluminescent device having excellent device characteristics such as efficiency can be provided.

  In this embodiment mode, a method for manufacturing an electroluminescent element of the present invention will be described with reference to FIGS. In FIGS. 1A and 1B, common reference numerals are used.

  In the present invention, a part of the electroluminescent layer is formed on the electrode (first electrode) 106 formed on the substrate 105 by electrolytic polymerization using an apparatus as shown in FIG. In addition, as a material used for the board | substrate 105 here, glass, quartz, a transparent plastic etc. can be used, for example.

  In addition, the first electrode 106 may function as an anode or may function as a cathode. Further, a plurality of first electrodes 106 may be patterned on the substrate 105.

  Note that in the case where the first electrode 106 is an electrode that functions as an anode, an anode material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (a work function of 4.0 eV or more) is used. be able to. Specific examples of the anode material include ITO (indium tin oxide), indium oxide mixed with 2 to 20% zinc oxide (ZnO), IZO (indium zinc oxide), gold (Au), platinum (Pt ), Nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g. TiN) or the like can be used.

In the case where the first electrode 106 is an electrode that functions as a cathode, a cathode material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof having a low work function (work function of 3.8 eV or less) is used. be able to. Specific examples of the cathode material include elements belonging to Group 1 or Group 2 of the element periodic rule, that is, alkali metals such as Li and Cs, and alkaline earth metals such as Mg, Ca, and Sr, and alloys containing these (Mg : Ag, Al: Li) and compounds (LiF, CsF, CaF ₂ ), transition metals including rare earth metals can be used, but metals such as Al, Ag, ITO (including alloys) and the like It can also be formed by laminating.

  In addition, it is preferable that the anode material and cathode material mentioned above form a thin film by a vapor deposition method, sputtering method, etc., and film thickness shall be 10-500 nm.

  Note that in the electroluminescent element of the present invention, when the first electrode 106 is an anode, the second electrode to be formed later is a cathode.

  In addition, light generated by recombination of carriers in the electroluminescent layer is emitted from one or both of the first electrode 106 and the second electrode to the outside. That is, when light is emitted from the first electrode 106, the first electrode 106 is formed of a light-transmitting material, and when light is emitted from the second electrode side, the second electrode 106 is formed. The electrode is formed of a light transmissive material. In this embodiment, the case where the first electrode 106 is an anode made of a light-transmitting material and the second electrode is a cathode having a light-blocking property will be described.

  In FIG. 1A, an electrolytic solution 102 is provided in a reaction tank 101, and a first electrode 106 electrically connected to a power source 104 through a wiring 103 is formed in the electrolytic solution 102. A substrate 105, a counter electrode 107, and a reference electrode 108 are provided. Note that the substrate 105 is fixed by a support body 109 that electrically connects the first electrode 106 and the wiring 103.

  The power source 104 is composed of a potentiostat capable of applying a constant potential and a coulomb meter that measures the amount of energized electricity. The counter electrode 107 is made of platinum. Further, the reference electrode 108 is made of Ag / AgCl.

  The reaction tank 101 is provided on a magnetic stirrer 110. The rotor 111 in the electrolytic solution 102 is controlled by the magnetic stirrer 110, and the electrolytic solution 102 is continuously stirred.

Then, when a predetermined current is supplied from the power source 104 to the first electrode 106 on the substrate 105 through the counter electrode 107 and the support 109, the monomer (monomer) or oligomer (low weight) in the electrolytic solution 102 is supplied. The first electroluminescent layer (electrolytic polymer film) 112 containing the polymer (high polymer) as a main component is formed on the surface of the first electrode 106 by polymerization. Note that in the present invention, the area of the first electrode 106 is 0.04 cm ² , the current flowing from the power source 104 is 0.016 to 0.06 mA, and the current flowing time is 0.8 to 3.0 sec. When the surface roughness is 6.0 nm or less, an electropolymerized film having a surface roughness of 6.0 nm or less, preferably 4.0 to 5.0 nm can be formed. It is possible to prevent a decrease in light emission efficiency and deterioration of the element due to concentration of electrolysis which is a problem, and it is possible to improve element characteristics and extend the life.

  In the present invention, examples of the supporting electrolyte contained in the electrolytic solution 102 include sodium perchlorate (sodium perchlorate), lithium perchlorate, tetrabutylammonium perchlorate (hereinafter referred to as TBAP), tetrabutylammonium tetrafluoroborate, and the like. Salts, other bases, acids and the like can be used. As the solvent used for the electrolytic solution 102, one of water, acetonitrile, benzonitrile, N, N-dimethylformamide, dichloromethane, tetrahydrofuran, propion carbonate, or a mixture of a plurality of types can be used. .

  Furthermore, as a monomer or oligomer contained in the electrolytic solution 102, thiophene (specifically, thiophene, 3,4-ethylenedioxythiophene, etc.), pyrrole (specifically, pyrrole, indole, etc.), aromatic, etc. In addition to hydrocarbon-based materials (specifically, benzene, naphthalene, azulene, etc.), aniline, phenylene oxide, and the like can be used.

  Next, the second electroluminescent layer 113 is formed on the first electroluminescent layer 112. Note that in the present invention, when the first electroluminescent layer 112 is formed of a material that can emit light in a single layer (including the light emitting layer), the second electrode is formed over the first electroluminescent layer 112. Although the first electroluminescent layer 112 is a hole injection layer made of an electrolytic polymerization film in this embodiment mode, the second electroluminescent layer can be formed on the first electroluminescent layer 112. A layer 113 (a layer including a light-emitting layer) is stacked. This case will be described with reference to FIG.

  In this embodiment, the first electroluminescent layer 112 is a hole injection layer, and the second electroluminescent layer 113 can be formed with a single layer or a stacked structure including at least a light emitting layer. Note that in the case of forming a stacked structure, in addition to the light emitting layer, a hole transport layer, a hole blocking layer (also referred to as a hole blocking layer), an electron transport layer, and the like are used in combination. Or the like.

  In addition, when the 1st electroluminescent layer 112 which consists of an electrolytic polymerization film forms a hole injection layer, among the monomers or oligomers mentioned above, thiophene, pyrrole-based materials such as thiophene, 3,4- In addition to ethylenedioxythiophene, pyrrole, and indole, aniline, phenylene oxide, and the like can be used.

  Note that in the case where the second electroluminescent layer 113 includes a hole transport layer, the hole transport material is preferably an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond). It is. Widely used materials include, for example, 4,4′-bis [N- (3-methylphenyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as TPD) and derivatives thereof 4, 4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as α-NPD) and 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) ) -Triphenylamine (hereinafter referred to as TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl-amino] -triphenylamine (hereinafter referred to as MTDATA) And starburst type aromatic amine compounds.

Further, as a light-emitting material for forming the light-emitting layer included in the second electroluminescent layer 113, specifically, tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ), tris (4-methyl-8) - quinolinolato) aluminum (hereinafter, referred to as Almq _3), bis (10-hydroxybenzo [h] - quinolinato) beryllium (hereinafter, referred to as BeBq _2), bis (2-methyl-8 quinolinolato) - (4-hydroxy -Biphenylyl) -aluminum (hereinafter referred to as BAlq), bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (hereinafter referred to as Zn (BOX) ₂ ), bis [2- (2-hydroxy In addition to metal complexes such as (phenyl) -benzothiazolate] zinc (hereinafter referred to as Zn (BTZ) ₂ ), various fluorescent dyes are effective. A triplet light emitting material is also possible, and is mainly a complex having platinum or iridium as a central metal. As the triplet light emitting material, tris (2-phenylpyridine) iridium (hereinafter referred to as Ir (ppy) ₃ ), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin -Platinum (hereinafter referred to as PtOEP) or the like can be used.

  In the case where the second electroluminescent layer 113 includes a hole blocking layer, BAlq, 1,3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl] benzene (hereinafter referred to as OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4- Triazole (hereinafter referred to as TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (hereinafter p-EtTAZ) Or the like, bathophenanthroline (hereinafter referred to as BPhen), bathocuproin (hereinafter referred to as BCP), or the like can be used.

In the case where the second electroluminescent layer 113 includes an electron transport layer, examples of the electron transport material include a metal complex having a quinoline skeleton or a benzoquinoline skeleton such as Alq ₃ , Almq ₃ , and BeBq ₂ , and a mixture A ligand complex such as BAlq ₂ is preferred. There are also metal complexes having oxazole-based and thiazole-based ligands such as Zn (BOX) ₂ and Zn (BTZ) ₂ . Furthermore, in addition to metal complexes, oxax such as 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (hereinafter referred to as PBD), OXD-7, and the like. Diazole derivatives, triazole derivatives such as TAZ and p-EtTAZ, and phenanthroline derivatives such as bathophenanthroline (BPhen) and bathocuproin (BCP) can be used.

  Next, a second electrode 114 serving as a cathode is formed on the second electroluminescent layer 113. Note that the above-described materials may be used as a cathode material for forming the second electrode.

  As described above, an electroluminescent element including an electroluminescent layer formed by electrolytic polymerization between the first electrode 106 and the second electrode which are a pair of electrodes can be formed.

  In this example, an electroluminescent element using an electropolymerized film formed by an electropolymerization method as an electroluminescent layer will be described with reference to FIG.

On the substrate 300, a first electrode 301 is formed of ITO. Note that the electrode area of the first electrode 301 in this embodiment is 2 × 2 mm ² .

  Then, the first electroluminescent layer 302 is formed over the first electrode 301 by the electrolytic polymerization method described with reference to FIG. In the electrolytic solution in the reaction vessel, 10 mM thiophene is used as a monomer, acetonitrile is used as a solvent, and 0.1 M TBAP is used as a supporting electrolyte.

After the substrate 300 is fixed to the support, it is immersed in the electrolytic solution. Next, the first electroluminescent layer 302 is formed on the first electrode 301 by flowing a predetermined current from the power source for a predetermined time. Note that the electrode area of the first electrode 301 in this embodiment is 2 × 2 mm ² . In addition, since the film thickness of the film formed in the case of the electrolytic polymerization method is determined by the total charge amount per unit area (mC / cm ² ), the total charge amount per unit area is 1.2 here. By controlling the current flow time so as to be (mC / cm ² ), the first functioning as a hole injection layer 311 is made of an electrolytic polymerization film (PEDOT: poly (3,4-ethylene dioxythiophene)). An electroluminescent layer 302 is formed.

  After forming the first electroluminescent layer 302, the substrate can be taken out of the electrolytic solution together with the support and vacuum-dried at room temperature to 150 ° C., whereby the substrate can be dried. Dry the substrate at 110 ° C.

  Next, a second electroluminescent layer 303 is formed on the first electroluminescent layer 302. In this embodiment, the second electroluminescent layer 303 has a stacked structure of a hole transport layer 312 and a light emitting layer 313 and is formed by an evaporation method.

  Here, the substrate 300 on which the first electroluminescent layer 302 is formed is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus with the surface on which the first electroluminescent layer 302 is formed facing downward, and the inside of the vacuum vapor deposition apparatus. Then, α-NPD is put in the evaporation source provided in, and the hole transport layer 312 is formed with a film thickness of 30 nm by a vapor deposition method using a resistance heating method.

Next, the light emitting layer 313 is formed. Note that holes and electrons recombine in the light-emitting layer 313 to emit light. Here, Alq ₃ is formed with a film thickness of 50 nm by a similar method.

  After the first electroluminescent layer 302 and the second electroluminescent layer 303 are stacked, a second electrode 304 that functions as a cathode is formed by a sputtering method or an evaporation method. In this embodiment, a film made of calcium fluoride (CaF) (2 nm) and a film made of aluminum (Al) (100 nm) are sequentially stacked on the second electroluminescent layer 303 by an evaporation method. A second electrode 304 is formed.

  Here, regarding the flatness of the film surface with respect to the current density at the time of film formation of the first electroluminescent layer 302 formed by the electrolytic polymerization method, surface observation is performed using an atomic force microscope (AFM). It was. The measurement conditions are as shown in Table 1, and the results are shown in FIGS. 10A shows the surface state on the first electrode 301 formed of ITO, and FIGS. 10B to 10D and FIGS. 11A to 11D show the first state. The surface state of the first electroluminescent layer 302 formed under the conditions shown in Table 1 for the current density applied to the electrode 301 and the current flow time is shown.

  FIG. 4 shows the flatness of the film surface obtained from the surface observation shown in FIGS. The average surface roughness (Ra) is used for the flatness of the film surface. The average surface roughness referred to here is a three-dimensional extension of the centerline average roughness defined in JIS B0601 (1982) so that it can be applied to the surface.

  In FIG. 4, the horizontal axis represents the value obtained by converting the current value flowing from the power source during electropolymerization into the current density per unit area, and the vertical axis represents the average surface roughness (Ra) of the film formed. ing.

From this result, when the current density is in the range of (0.4 to 1.5 mA / cm ² ) and the time for passing the current is in the range of (0.8 to 3.0 sec), the average surface roughness ( It can be seen that Ra) can be made particularly small and a film having excellent flatness can be formed.

  Further, a second electroluminescent layer and a second electrode are formed on the first electroluminescent layer formed by electrolytic polymerization under the same conditions as those shown in FIG. FIG. 5 shows the measurement results of the element characteristics of the electroluminescent element. Note that current efficiency (cd / A) is used for the element characteristics of the electroluminescent element.

In FIG. 5, the horizontal axis represents the current density applied to the first electrode during the electropolymerization, and the average surface roughness (Ra) on the film surface of the first electroluminescent layer formed by the electropolymerization method is shown on the left side. The current efficiency of the electroluminescent element is plotted on the right vertical axis. In this case as well, the electrode area is 2 × 2 mm ² , and the current density and current flow time are controlled so that the total charge amount per unit area is 1.2 (mC / cm ² ). Yes. That is, here, the current densities are 0.20 (mA / cm ² ), 0.4 (mA / cm ² ), and 0.6 (mA / cm ² ), respectively, and the current flow time is 6 (Sec), 3 (sec), 2 (sec), the average surface roughness (Ra) of the film surface and the measurement results for the current efficiency are shown.

From these results, it was found that the current efficiency is improved by controlling the current density to reduce the average surface roughness in terms of current density, average surface roughness, and current efficiency. Furthermore, from the results shown in FIG. 4 and FIG. 5, the current density is set in the range of 0.4 (mA / cm ² ) to 1.5 (mA / cm ² ), and the current flow time is 0.8. It can be seen that the average surface roughness (Ra) of the formed film surface can be reduced and the current efficiency is improved by setting the range of (sec) to 3.0 (sec).

Further, paying attention to S atoms contained in thiophene, measurement was performed by secondary ion mass spectrometry (SIMS). Here, the EL element shown in FIG. 3 was used as a sample, and primary ions (Cs ⁺ ) were irradiated from the second electrode side. As shown in FIG. 12, the peak of the secondary ion intensity of S is observed in the portion where the secondary ion intensity of C + N, C, and H starts to decrease rapidly and the secondary ion intensity of In + O increases rapidly. It was seen. Therefore, formation of the 1st electroluminescent layer which consists of an electropolymerization film on the 1st electrode containing In was confirmed. The SIMS used here is a method in which the surface of a solid sample is irradiated with an ion beam in a vacuum, and secondary ions (component atoms of the sample) that jump out of the sample are separated for each mass / charge ratio and mass analyzed. is there.

  In this embodiment, a driver circuit portion and a pixel portion are formed on the same substrate, and the pixel portion is an active matrix type in which a plurality of electroluminescent elements each having an electroluminescent layer formed by electrolytic polymerization in the present invention are formed. The case of forming a panel will be described with reference to FIGS.

  A source-side driver circuit 602, a gate-side driver circuit 603, and a pixel portion 604 which are driver circuit portions are formed over a substrate 601 illustrated in FIG. 6A. The pixel portion 604 includes signal lines 605, A scanning line 606 and a current supply line 607 are formed. In addition, the source side driver circuit 602 and the gate side driver circuit 603 are connected to the outside by a lead wiring 608. Similarly, the current supply line 607 is connected to the outside by the lead wiring 608.

  Note that the lead wiring 608 can be electrically connected to the outside by being connected to the FPC 610 in the connection portion 609.

  Here, an enlarged view of the pixel portion 604 is shown in FIG. In the pixel portion 604, a plurality of first electrodes 611 that form a plurality of pixels are formed. Note that, although not shown here, the first electrode 611 is electrically connected to a TFT previously formed over the substrate through a wiring.

  In addition, a signal line 605, a scanning line 606, and a current supply line 607 are formed around the first electrode 611, and these are insulating layers 612 formed except on the first electrode 611. Covered by.

  In this embodiment, a predetermined current is supplied from the power source to the first electrode 611 formed on the panel in this way via the FPC 610, and the first electrode which is a part of the electroluminescent layer is formed on the first electrode. Electropolymerization is performed to form an electroluminescent layer. Note that the method for electrolytic polymerization can be similarly performed using the apparatus illustrated in FIG.

Note that the panel in this embodiment has a diagonal size of 1.89 inch, an area of a pixel portion of 11.56 cm ² , and a number of pixels of 176 × 3 × 184, and is formed in each pixel. The electrode area of the exposed portion of the electrode 611 is 5412 μm ² . Here, since the first electroluminescent layer made of the electrolytic polymerization film is simultaneously formed on all the first electrodes 611 of the pixel portion, the electrode area here is 5.26 cm ² .

  In the electrolytic solution in the reaction vessel, 10 mM thiophene is used as a monomer, acetonitrile is used as a solvent, and 0.1 M TBAP is used as a supporting electrolyte.

  In this example, an electropolymerized film to be the first electroluminescent layer can be formed by applying a current of 3.156 mA for 2 seconds.

  In addition, after forming an electropolymerization film | membrane, a board | substrate is taken out from electrolyte solution with a support body, and the drying process of a board | substrate is performed by vacuum-drying at 110 degreeC.

  After forming the first electroluminescent layer on the first electrode 611 in this manner, another layer is stacked to form an electroluminescent element as shown in FIG. Note that after the first electroluminescent layer is formed, the FPC shown in FIG. 6A is once removed, and an electroluminescent element can be manufactured by performing the subsequent steps. FIG. 7 illustrates a cross-sectional structure of part of a pixel formed in the pixel portion illustrated in FIG.

  Note that the first electrode 611 is electrically connected to a TFT 620 including a source region 614, a drain region 615, a channel formation region 616, a gate insulating film 617, and a gate electrode 618 through a wiring 619. The ends of the TFT 620 and the first electrode 611 are covered with an insulating layer 612.

  A second electroluminescent layer 622 is formed on the first electroluminescent layer 613. Note that the second electroluminescent layer 622 in this example is similar to the structure shown in Example 1, has a stacked structure of a hole transport layer and a light-emitting layer, and is formed by an evaporation method.

  Further, the second electrode 623 is formed over the second electroluminescent layer 622, whereby the electroluminescent element 624 is formed.

  As described above, by implementing this embodiment, a panel having a drive circuit portion and a pixel portion on the same substrate, and having an electroluminescent layer formed by using the electrolytic polymerization method of the present invention A panel having elements can be formed.

  In this embodiment, a light-emitting device having the electroluminescent element of the present invention in a pixel portion will be described with reference to FIG. 8A is a top view illustrating the light-emitting device, and FIG. 8B is a cross-sectional view taken along line A-A ′ in FIG. 8A. 801 indicated by a dotted line is a source side driver circuit, 802 is a pixel portion, and 803 is a gate side driver circuit. Reference numeral 804 denotes a sealing substrate, reference numeral 805 denotes a sealing agent, and an inner side 807 surrounded by the sealing agent 805 is a space.

  Reference numeral 808 denotes a routing wiring for transmitting signals input to the source side driver circuit 801 and the gate side driver circuit 803, and a video signal, a clock signal, and a start signal from an FPC (flexible printed circuit) 809 serving as an external input terminal. Receive signals, reset signals, etc. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure is described with reference to FIG. A driver circuit portion and a pixel portion are formed over the substrate 810. Here, a source side driver circuit 801 which is a driver circuit portion and a pixel portion 802 are shown.

  Note that the source side driver circuit 801 is a CMOS circuit in which an n-channel TFT 823 and a p-channel TFT 824 are combined. The TFT forming the driving circuit may be formed by a known CMOS circuit, PMOS circuit or NMOS circuit. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not always necessary, and the driver circuit may be formed outside the substrate.

  The pixel portion 802 is formed of a plurality of pixels including a switching TFT 811, a current control TFT 812, and a first electrode 813 electrically connected to the drain thereof. Note that an insulator 814 is formed to cover an end portion of the first electrode 813. Here, a positive photosensitive acrylic resin film is used.

  In order to improve the film forming property, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 814. For example, in the case where positive photosensitive acrylic is used as a material for the insulator 814, it is preferable that only the upper end portion of the insulator 814 have a curved surface having a curvature radius (0.2 μm to 3 μm). As the insulator 814, either a negative type that becomes insoluble in an etchant by photosensitive light or a positive type that becomes soluble in an etchant by light can be used.

  An electroluminescent layer 816 and a second electrode 817 are formed over the first electrode 813, respectively. Here, as a material used for the first electrode 813 functioning as an anode, a material having a high work function is preferably used. For example, ITO (Indium Tin Oxide) film, Indium Zinc Oxide (IZO) film, Titanium nitride film, Chromium film, Tungsten film, Zn film, Pt film, etc., as well as titanium nitride and aluminum as main components And a three-layer structure of a titanium nitride film, a film containing aluminum as its main component, and a titanium nitride film can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained.

  In addition, the electroluminescent layer 816 is formed by using the electrolytic polymerization method of the present invention. However, in the case of a laminated structure, the electroluminescent layer 816 is formed by an electroluminescent layer formed of an electropolymerized film and other film forming methods. An electroluminescent layer can also be laminated. Note that as another method for forming the electroluminescent layer, an evaporation method using an evaporation mask, a coating method, or an inkjet method can be used.

  Of the electroluminescent layer 816, a film formed by an electrolytic polymerization method is formed by an oligomer (low polymer) or a polymer (high polymer), but an electroluminescent layer formed by another method is low It may be a molecular material or a polymer material. Furthermore, not only an organic compound is used in a single layer or a stacked layer, but also an inorganic compound can be used in a part of a film made of the organic compound.

Further, as a material used for the second electrode (cathode) 817 formed over the electroluminescent layer 816, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof such as MgAg, MgIn, AlLi, and An inorganic compound CaF ₂ or CaN) may be used. Note that in the case where light generated in the electroluminescent layer 816 passes through the second electrode 817, a thin metal film and a transparent conductive film (ITO (indium oxide) are used as the second electrode (cathode) 817. A stack with a tin oxide alloy), an indium zinc oxide alloy (In ₂ O ₃ —ZnO), zinc oxide (ZnO), or the like) is preferably used.

  Further, the sealing substrate 804 is bonded to the element substrate 810 with the sealant 805, whereby the electroluminescent element 818 is provided in the space 807 surrounded by the element substrate 810, the sealing substrate 804, and the sealant 805. ing. Note that the space 807 includes a structure filled with a sealant 805 in addition to a case where the space is filled with an inert gas (such as nitrogen or argon).

  Note that an epoxy resin is preferably used for the sealant 805. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used as a material for the sealing substrate 804.

  As described above, a light-emitting device having the electroluminescent element of the present invention can be obtained.

  Note that the light-emitting device described in this embodiment can be implemented by freely combining the configurations of the electroluminescent elements described in Embodiment 1 or Embodiment 2.

  In this example, various electric appliances completed using a light-emitting device having the electroluminescent element of the present invention will be described.

  As an electric appliance manufactured using a light emitting device having an electroluminescent element of the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, an acoustic reproduction device (car audio, audio component, etc.), Notebook personal computer, game machine, portable information terminal (mobile computer, cellular phone, portable game machine or electronic book, etc.), image playback device equipped with a recording medium (specifically, DVD (Digital Versatile Disc and Digital Video Disc)) For example, a device provided with a display device capable of reproducing the recording medium and displaying the image. Specific examples of these electric appliances are shown in FIG.

  FIG. 9A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. It is manufactured by using a light emitting device having the electroluminescent element of the present invention for the display portion 2003. The display device includes all information display devices such as a personal computer, a TV broadcast reception, and an advertisement display.

  FIG. 9B illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. It is manufactured by using a light emitting device having the electroluminescent element of the present invention for the display portion 2203.

  FIG. 9C illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. It is manufactured by using a light emitting device having an electroluminescent element of the present invention for the display portion 2302.

  FIG. 9D illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, and a recording medium (DVD or the like). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. The display portion A 2403 mainly displays image information, and the display portion B 2404 mainly displays character information. The display portion A 2403 is manufactured by using the light-emitting device having the electroluminescent element of the present invention for the display portions A, B 2403 and 2404. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.

  FIG. 9E illustrates a goggle type display (head mounted display), which includes a main body 2501, a display portion 2502, and an arm portion 2503. It is manufactured by using a light emitting device having the electroluminescent element of the present invention for the display portion 2502.

  FIG. 9F illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and an eyepiece. Part 2610 and the like. It is manufactured by using a light emitting device having the electroluminescent element of the present invention for the display portion 2602.

  Here, FIG. 9G shows a cellular phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. It is manufactured by using a light emitting device having the electroluminescent element of the present invention for the display portion 2703.

  As described above, the applicable range of the light-emitting device having the electroluminescent element of the present invention is extremely wide, and the electroluminescent element of the present invention is excellent in element characteristics such as luminous efficiency, and therefore includes this electroluminescent element. By applying the light emitting device to electric appliances in various fields, low power consumption and long life can be realized.

The figure explaining the electrolytic polymerization method. 3A and 3B illustrate an element structure of an electroluminescent element. 3A and 3B illustrate an element structure of an electroluminescent element. The graph shown about the relationship between an electric current density and average surface roughness. The graph shown about the relationship between average surface roughness and current efficiency. 10A and 10B each illustrate an active matrix panel. Sectional drawing explaining the electroluminescent element connected with TFT. FIG. 6 illustrates a light-emitting device. The figure explaining an electric appliance. AFM photograph of surface condition. AFM photograph of surface condition. The result of the SIMS measurement about the electroluminescent element of FIG.

Claims (5)

A method for manufacturing an electroluminescent element having an electroluminescent layer between a first electrode and a second electrode,
Forming the first electrode on a substrate;
The total charge amount per unit area in the first electrode is 1.0 mC / cm ^{2 to} 1.2 mC / cm ² , the applied current density is 0.4 mA / cm ^{2 to} 1.5 mA / cm ² , and The electroluminescent layer is formed on the first electrode by an electropolymerization method with a current flowing time of 0.8 sec to 3.0 sec,
A method for manufacturing an electroluminescent element, wherein the second electrode is formed on the electroluminescent layer. In claim 1 ,
The electroluminescent layer is formed using any one of pyrrole, indole, thiophene, 3,4-ethylenedioxythiophene, benzene, naphthalene, azulene, aniline, or phenylene oxide. Manufacturing method. A method of manufacturing an electroluminescent element having a first electroluminescent layer and a second electroluminescent layer having a laminated structure between a first electrode and a second electrode,
Forming the first electrode on a substrate;
The total charge amount per unit area in the first electrode is 1.0 mC / cm ^{2 to} 1.2 mC / cm ² , the applied current density is 0.4 mA / cm ^{2 to} 1.5 mA / cm ² , and The time for passing current is set to 0.8 sec to 3.0 sec, and the first electroluminescent layer is formed on the first electrode by an electrolytic polymerization method.
Forming the second electroluminescent layer on the first electroluminescent layer by vapor deposition;
A method for manufacturing an electroluminescent element, wherein the second electrode is formed on the second electroluminescent layer. A method for producing an electroluminescent element having a hole injection layer, a hole transport layer and a light emitting layer between a first electrode and a second electrode,
Forming the first electrode on a substrate;
The total charge amount per unit area in the first electrode is 1.0 mC / cm ^{2 to} 1.2 mC / cm ² , the applied current density is 0.4 mA / cm ^{2 to} 1.5 mA / cm ² , and The time for flowing current is set to 0.8 sec to 3.0 sec, and the hole injection layer is formed on the first electrode by an electrolytic polymerization method.
Forming the hole transport layer and the light emitting layer on the hole injection layer by vapor deposition,
A method for manufacturing an electroluminescent element, wherein the second electrode is formed on the light emitting layer. In any one of claims 1 to 4, wherein the electroluminescent layer or the first electroluminescent layer, electrolytic polymerization monomers or oligomers on the surface of the first electrode is mainly composed of a polymer polymerized by electrolytic polymerization A method for manufacturing an electroluminescent element, which is a film.