JP5446705B2 - Organic thin film manufacturing method, organic thin film, organic electronics element, organic electroluminescence element, lighting device and display element - Google Patents

Description

  The present invention relates to a method for producing an organic thin film, an organic thin film, an organic electronics element, an organic electroluminescent element (hereinafter also referred to as an organic EL element), a lighting device, and a display element.

Organic electronics elements are elements that perform electrical operations using organic substances, and are expected to exhibit features such as energy saving, low cost, and flexibility, and are attracting attention as a technology that can replace conventional inorganic semiconductors based on silicon. ing.
An organic EL element, an organic photoelectric conversion element, an organic transistor etc. are mentioned as an example of an organic electronics element.

  Among organic electronics elements, organic EL elements are attracting attention as applications for large-area solid-state light sources as an alternative to incandescent lamps and gas-filled lamps, for example. It is also attracting attention as the most powerful self-luminous display that can replace the liquid crystal display (LCD) in the flat panel display (FPD) field, and its commercialization is progressing.

  Organic EL elements are roughly classified into two types, low molecular organic EL elements and polymer organic EL elements, depending on the materials and film forming methods used. High-molecular organic EL elements are composed of high-molecular materials, and can be used for simple film formation such as printing and ink-jet compared to low-molecular organic EL elements that require vacuum-based film formation. Therefore, it is an indispensable element for future large-screen organic EL displays.

  Although research has been conducted energetically for both low-molecular organic EL elements and high-molecular organic EL elements, low luminous efficiency and short element lifetime are still serious problems. As one means for solving this problem, multilayering is performed in the low molecular organic EL element.

  FIG. 1 shows an example of a multilayered organic EL element. In FIG. 1, the layer responsible for light emission is described as the light emitting layer 1, and the layer in contact with the anode 2 is described as the hole injection layer 3, and the layer in contact with the cathode 4 is described as the electron injection layer 5. Furthermore, when a different layer exists between the light emitting layer 1 and the hole injection layer 3, it is described as a hole transport layer 6, and when a different layer exists between the light emitting layer 1 and the electron injection layer 5, an electron transport is described. It is described as layer 7. In FIG. 1, 8 is a substrate.

Since the low molecular organic EL element is formed by vapor deposition, multilayering can be easily achieved by performing vapor deposition while sequentially changing the compounds to be used. On the other hand, since a polymer type organic EL element forms a film using a wet process such as printing or inkjet, there arises a problem that the lower layer dissolves when the upper layer is applied.
For this reason, it is difficult to make a polymer organic EL element multi-layered as compared to a low molecular organic EL element, and it has not been possible to obtain an effect of improving luminous efficiency and life.

  To address this problem, several methods have been proposed so far. One is a method using a difference in solubility. For example, it is an element having a two-layer structure of a water-soluble polythiophene: polystyrene sulfonic acid (PEDOT: PSS) hole injection layer and a light-emitting layer formed using an aromatic organic solvent such as toluene. In this case, since the PEDOT: PSS layer is not dissolved in an aromatic solvent such as toluene, a two-layer structure can be produced.

Non-Patent Document 1 proposes an element having a three-layer structure using compounds having greatly different solubilities. Patent Document 1 discloses an element having a three-layer structure in which a layer called an interlayer is introduced on PEDOT: PSS.
In addition, in Non-Patent Documents 2 to 4, in order to overcome such problems, the solubility of the compound is changed using a polymerization reaction of a siloxane compound, an oxetane group, a vinyl group, etc., and the thin film is insolubilized in a solvent. A method is disclosed.

  These multi-layered methods are important. However, when water-soluble PEDOT: PSS is used, it is necessary to remove moisture remaining in the thin film, and the materials that can be used are limited in order to utilize the difference in solubility. In other words, the siloxane compound is unstable to moisture in the air and the device characteristics are not sufficient.

  In order to utilize these polymerization reactions, it is necessary to add an appropriate polymerization initiator that generates an acid, base, radical or the like by reacting or decomposing by stimulation such as light or heat.

However, the polymerization initiator and the decomposition product thereof basically have no charge transport property necessary for driving the organic EL device or are not sufficient. Therefore, in particular, if it remains on the surface layer of the charge transport film, which is the interface with the upper layer, it may act as a carrier trap and hinder the transport of charges, There was a risk of degrading the layer.
On the other hand, in order to improve the light emission efficiency and lifetime of the organic EL device, an attempt has been made to mix an electron accepting compound with a charge transporting compound.

For example, in Patent Document 3, tris (4-bromophenylaminium hexachloroantimonate) (tris (4-bromophenylamine hexachloroantimonate): TBPAH) is mixed with a hole transporting polymer compound as an electron accepting compound. It is disclosed that an organic electroluminescence device capable of being driven at a low voltage can be obtained.
Patent Document 4 discloses that iron (III) chloride (FeCl ₃ ) is mixed with a hole transporting compound as an electron accepting compound by a vacuum deposition method.

  In Patent Document 5, tris (pentafluorophenyl) borane (PPB) as an electron-accepting compound is mixed with a hole-transporting polymer compound by a wet film formation method to form holes. Forming an injection layer is disclosed.

Thus, it is considered important to generate a compound composed of a radical cation and a counter anion of a charge transporting compound, which is generated when an electron accepting compound is mixed with the charge transporting compound.
Patent Document 6 discloses a composition comprising a specific aminium cation radical as a composition for a charge transport film.

From this, for example, when an excessive electron-accepting compound is mixed with the charge transporting compound, the electron-accepting compound remains as it is. The remaining electron-accepting compound, particularly the electron-accepting compound remaining at the interface with the adjacent electrode or layer, may function as an impurity that traps carriers or a substance that quenches light emission.
However, in Examples in Patent Documents 3 to 5, the film forming method on the charge transport film mixed with the electron accepting compound is a vacuum vapor deposition method, and there is no description regarding a cleaning step before vapor deposition.

Further, in Patent Document 6, there is an example in which the film is formed on the charge transport film by a wet method, but there is no description regarding the cleaning process before the lamination.
On the other hand, in the manufacturing method of an organic EL element, Patent Document 7 discloses a manufacturing process including a process of removing a non-modified portion of a crosslinkable organic compound with a solvent. This step is for removing the unmodified crosslinkable compound, and there is no description regarding the ionic compound or the polymerizable initiator.

JP 2007-1119763 A International Publication No. 08/010487 Pamphlet Japanese Patent No. 3748491 Japanese Patent Laid-Open No. 11-251067 Japanese Patent No. 4023204 JP 2006-233162 A Japanese Patent No. 4,175,397

Y. Goto, T .; Hayashida, M .; Noto, IDW '04 Proceedings of The 11th International Display Works, 1343-1346 (2004) H. Yan, P.M. Lee, N.M. R. Armstrong, A.M. Graham, G.M. A. Evemenko, P.M. Dutta, T.A. J. et al. Marks, J.A. Am. Chem. Soc. , 127, 3172-4183 (2005) E. Bacher, M.M. Bayerl, P.A. Rudati, N .; Reckfuss, C.I. David, K.D. Meerholz, O.M. Nuyken, Macromolecules, 38, 1640 (2005). M.M. S. Liu, Y .; H. Niu, J .; W. Ka, H .; L. Yip, F.A. Huang, J. et al. Luo, T .; D. Wong, A.D. K. Y. Jen, Macromolecules, 41, 9570 (2008) M.M. A. Baldo et al. , Nature, vol. 395, p. 151 (1998) M.M. A. Baldo et al. , Applied Physics Letters, vol. 75, p. 4 (1999) M.M. A. Baldo et al. , Nature, vol. 403, p. 750 (2000)

In order to increase the efficiency and life of organic EL elements, it is desirable to divide the organic layers into layers and separate the functions of each layer. However, the organic layers can be formed using a wet process that is easy to form even in large areas. In order to increase the number of layers, it is necessary to prevent the lower layer from being dissolved during the formation of the upper layer, and a change in solubility in a solvent utilizing a polymerization reaction has been used.
It is necessary to add an appropriate initiator to this polymerization reaction, but this initiator and its decomposition products remain in the polymerization layer, particularly at the interface with adjacent electrodes and layers, and the efficiency and life of the organic EL device. There is a concern of lowering.
On the other hand, attempts have been made to mix an electron-accepting compound with a charge-transporting compound, but an excess of the electron-accepting compound remains in the layer, particularly at the interface with an adjacent electrode or layer. There is a concern of reducing the lifespan.

  An object of this invention is to provide the manufacturing method of an organic thin film useful in improving the light emission efficiency and light emission lifetime of a polymer type organic EL element in view of the above-mentioned problem. Furthermore, it aims at providing the organic thin film produced using this manufacturing method, the organic electronics element and organic EL element using this organic thin film, an illuminating device, and a display element.

As a result of intensive studies, the present inventors have found that a process of cleaning the charge transport film after forming the charge transport film is useful, and further, found a cleaning agent that can be used in the cleaning process, The present inventors have found that the charge transport film formed by the method is useful for improving the efficiency and extending the life of the organic EL device, and completed the present study.
That is, the present invention is characterized by the following matters.
(1) In a method for producing an organic thin film having a laminated structure, a thin film containing a compound having a charge transporting unit (hereinafter referred to as a charge transporting compound) and an ionic compound (hereinafter referred to as a charge transporting film) is washed. A method for producing an organic thin film, further comprising a step of forming a thin film on the thin film (hereinafter referred to as a cleaning step).
(2) The method for producing an organic thin film, wherein the charge transporting unit is any one of an aromatic amine, carbazole, and thiophene.
(3) The method for producing an organic thin film as described above, wherein the ionic compound is an onium salt.
(4) The manufacturing method of the said organic thin film whose charge transport compound is a polymer or an oligomer.
(5) The method for producing an organic thin film as described above, wherein the polymer or oligomer has one or more polymerizable substituents.
(6) The method for producing an organic thin film described above, wherein the polymerizable substituent is any one of an oxetane group, an epoxy group, a vinyl group, a vinyl ether group, an acrylate group, and a methacrylate group.
(7) The method for producing an organic thin film as described above, wherein the charge transport film contains a polymerization initiator.
(8) The method for producing an organic thin film as described above, comprising an ionic compound as a polymerization initiator.
(9) The method for producing an organic thin film as described above, wherein the cleaning agent used in the cleaning step contains a basic compound.
(10) The method for producing an organic thin film as described above, wherein the cleaning agent used in the cleaning step includes a basic compound and a solvent.
(11) An organic thin film produced by the method for producing an organic thin film.
(12) An organic electronic device comprising the organic thin film.
(13) An organic electroluminescent element comprising the organic thin film on a substrate.
(14) The organic electroluminescence device as described above, wherein the organic thin film is a hole injection layer.
(15) The organic electroluminescence device as described above, wherein the organic thin film is a hole transport layer.
(16) The organic electroluminescence device as described above, wherein the organic thin film is a light emitting layer.
(17) The organic electroluminescence device as described above, wherein the substrate is a flexible substrate.
(18) The organic electroluminescence device as described above, wherein the substrate is a resin film.
(19) A display device comprising the organic electroluminescence device.
(20) An illumination device including the organic electroluminescence element.
(21) A display element comprising the lighting device and a liquid crystal element as display means.

  The method for producing an organic thin film of the present invention comprises a carrier present on the surface of a thin film (hereinafter referred to as a charge transport film) containing a compound containing a charge transporting unit (hereinafter referred to as a charge transport compound) and an ionic compound. Production that is extremely useful for improving the luminous efficiency and lifetime of organic electronic devices including the charge transport film, particularly polymer organic EL devices, by removing impurities that can be trapped stably and easily Is the method.

It is a schematic diagram which shows an example of the multilayered organic EL element.

  The organic thin film manufacturing method of the present invention is a manufacturing method in which a charge transport film including a charge transport compound and an ionic compound is formed to form a laminated structure of organic thin films, and the thin film is formed on the charge transport film. It is characterized by including a step of cleaning the charge transport film (hereinafter referred to as a cleaning step). Hereinafter, the organic thin film is also referred to as a thin film.

Here, in the present invention, the “cleaning step” refers to a step of cleaning the surface layer after forming the charge transport film, which is different from the step of further forming a thin film on the charge transport film.
Here, the “charge transporting unit” in the present invention is an atomic group having the ability to transport holes or electrons, and the details thereof will be described below.

  The charge transporting unit is not particularly limited as long as it has an ability to transport holes or electrons, and is preferably an amine having an aromatic ring, carbazole, or thiophene. ) To (58).

In the above formula, E is, independently ^{-R 1, -OR 2, -SR 3} , -OCOR 4, -COOR 5, -SiR 6 R 7 R 8 or the general formula (59) - (61) (where R ^{1 to} R ¹¹ represent a hydrogen atom, a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms, or an aryl group or heteroaryl group having 2 to 30 carbon atoms, and a and b and c are Represents an integer greater than or equal to 1. Here, the aryl group is an atomic group obtained by removing one hydrogen atom from an aromatic hydrocarbon, and may have a substituent, and the heteroaryl group refers to a heteroatom. An atomic group obtained by removing one hydrogen atom from an aromatic compound, which may have a substituent.), Or a group represented by the following formula (excluding the formula (I)) Represents. Ar independently represents an arylene group having 2 to 30 carbon atoms or a heteroarylene group. An arylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon, and may have a substituent, for example, phenylene, biphenyl-diyl, terphenyl-diyl, naphthalene-diyl, anthracene-diyl , Tetracene-diyl, fluorene-diyl, phenanthrene-diyl and the like. The heteroarylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic compound having a hetero atom, and may have a substituent, such as pyridine-diyl, pyrazine-diyl, quinoline-diyl, isoquinoline. -Diyl, acridine-diyl, phenanthroline-diyl, furan-diyl, pyrrole-diyl, thiophene-diyl, oxazole-diyl, oxadiazole-diyl, thiadiazole-diyl, triazole-diyl, benzoxazole-diyl, benzooxadiazole -Diyl, benzothiadiazole-diyl, benzotriazole-diyl, benzothiophene-diyl and the like. X and Z are each independently a divalent linking group, and there is no particular limitation, but a group in which one hydrogen atom is further removed from a group having one or more hydrogen atoms in the R or a group represented by the following formula (I) The exemplified groups are preferred. x represents an integer of 0-2. Y is a trivalent linking group, and represents a group obtained by removing two hydrogen atoms from a group having two or more hydrogen atoms in R.

In addition, the charge transporting compound in the present invention may be a commercially available one, or one synthesized by a method known to those skilled in the art, and is not particularly limited.
In addition, the ionic compound in the present invention is preferably an onium salt from the viewpoint of improving charge transportability.

Here, the onium salt in the present invention refers to a compound composed of a cation such as sulfonium, iodonium, selenium, ammonium, phosphonium, bismuthium and a counter anion. Examples of anions include halogen ions such as F ⁻ , Cl ⁻ , Br ⁻ and I ⁻ ; OH ⁻ ; ClO ₄ ⁻ ; FSO ₃ ⁻ , ClSO ₃ ⁻ , CH ₃ SO ₃ ⁻ , C ₆ H ₅ SO ₃ ^−. , Sulfonate ions such as CF ₃ SO ₃ ^— , sulfate ions such as HSO ₄ ⁻ , SO ₄ ²⁻ ; carbonate ions such as HCO ₃ ⁻ , CO ₃ ²⁻ ; H ₂ PO ₄ ⁻ , HPO ₄ ^{2. -,} phosphate ion such as _{^{PO 4 3-; PF 6 -,}} PF 5 OH - fluorophosphate ions such _{^{as; BF 4 -, B (C}} 6 F 5) 4 -, B (C 6 H 4 CF _{3) 4} ^- borate ions such _{^{as; AlCl 4 -; BiF 6 -}} ; SbF 6 -, SbF 5 OH - fluoro antimonate ion such _{^{as; AsF 6 -, AsF 5 OH}} - fluoroarsenate periodate ions, such as And the like. The sulfonium ions include triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris (4-methoxyphenyl) sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, tris (4-fluorophenyl) ) Sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris (4-hydroxyphenyl) sulfonium, 4- (phenylthio) phenyldiphenylsulfonium, 4- (p-tolylthio) phenyldi-p-tolylsulfonium, 4 -(4-methoxyphenylthio) phenylbis (4-methoxyphenyl) sulfonium, 4- (phenylthio) phenylbis (4-fluorophenyl) sulfonium, 4- (phenylthio) Phenylbis (4-methoxyphenyl) sulfonium, 4- (phenylthio) phenyldi-p-tolylsulfonium, bis [4- (diphenylsulfonio) phenyl] sulfide, bis [4- {bis [4- (2-hydroxyethoxy) phenyl ] Sulfonio} phenyl] sulfide, bis {4- [bis (4-fluorophenyl) sulfonio] phenyl} sulfide, bis {4- [bis (4-methylphenyl) sulfonio] phenyl} sulfide, bis {4- [bis ( 4-methoxyphenyl) sulfonio] phenyl} sulfide, 4- (4-benzoyl-2-chlorophenylthio) phenylbis (4-fluorophenyl) sulfonium, 4- (4-benzoyl-2-chlorophenylthio) phenyldiphenylsulfonium, 4 -(4-Benzoy Phenylthio) phenylbis (4-fluorophenyl) sulfonium, 4- (4-benzoylphenylthio) phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p- Tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl) sulfonio] thioxanthone, 2-[(diphenyl) sulfonio] Thioxanthone, 4- [4- (4-tert-butylbenzoyl) phenylthio] phenyldi-p-tolylsulfonium, 4- [4- (4-tert-butylbenzoyl) phenylthio] phenyldiphenylsulfonium, 4- [4- (benzoyl) Phenylthio) ] Phenyldi-p-tolylsulfonium, 4- [4- (benzoylphenylthio)] phenyldiphenylsulfonium, 5- (4-methoxyphenyl) thiaanthrhenium, 5-phenylthiaanthrhenium, 5-tolylthiaanthrhenium, 5 Triarylsulfonium such as-(4-ethoxyphenyl) thiaanthrhenium, 5- (2,4,6-trimethylphenyl) thiaanthrhenium; diphenylphenacylsulfonium, diphenyl4-nitrophenacylsulfonium, diphenylbenzylsulfonium, diphenyl Diarylsulfonium such as methylsulfonium; phenylmethylbenzylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 4-methoxyphenylmethylbenzylsulfonium, 4-acetate Rubonyloxyphenylmethylbenzylsulfonium, 2-naphthylmethylbenzylsulfonium, 2-naphthylmethyl (1-ethoxycarbonyl) ethylsulfonium, phenylmethylphenacylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, 4-methoxyphenylmethylphenacylsulfonium Monoarylsulfonium such as 4-acetocarbonyloxyphenylmethylphenacylsulfonium, 2-naphthylmethylphenacylsulfonium, 2-naphthyloctadecylphenacylsulfonium, 9-anthracenylmethylphenacylsulfonium; dimethylphenacylsulfonium, phenacyl Tetrahydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydrothiophenium, Such trialkyl sulfonium such as data decyl methyl phenacyl sulfonium and the like, which are described in the following documents.

  Regarding triarylsulfonium, U.S. Pat. No. 4,231,951, U.S. Pat. No. 4,256,828, JP-A-7-61964, JP-A-8-165290, JP-A-7-10914, JP-A-7- No. 25922, JP-A-8-27208, JP-A-8-27209, JP-A-8-165290, JP-A-8-301991, JP-A-9-143212, JP-A-9-278813 JP-A-10-7680, JP-A-10-287463, JP-A-10-245378, JP-A-8-157510, JP-A-10-204083, JP-A-8-245666, JP-A-8-157451, JP-A-7-324069, JP-A-9-268205 JP-A-9-278935, JP-A-2001-288205, JP-A-11-80118, JP-A-10-182825, JP-A-10-330353, JP-A-10-152495, JP-A-10-152495 JP-A-5-239213, JP-A-7-333834, JP-A-9-12537, JP-A-8-325259, JP-A-8-160606, JP2000-186071 (US Pat. No. 6,368,769). In regard to diarylsulfonium, JP-A-7-300504, JP-A-64-45357, JP-A-64-29419, etc .; in terms of monoarylsulfonium, JP-A-6-345726 Gazette, JP-A-8-325225, JP-A-9-118663 U.S. Pat. No. 6,097,753), JP-A-2-196812, JP-A-2-1470, JP-A-2-196812, JP-A-3-237107, JP-A-3-17101, JP-A-6-228086, JP-A-10-152469, JP-A-7-300505, JP-A-2003-277353, JP-A-2003-277352, etc .; 308563, JP-A-5-140210, JP-A-5-140209, JP-A-5-230189, JP-A-6-271532, JP-A-58-37003, JP-A-2-178303 JP, 10-338688, JP 9-328506, JP 11-2 28534, JP-A-8-27102, JP-A-7-333834, JP-A-5-222167, JP-A-11-21307, JP-A-11-35613, US Pat. No. 6,031,014 Such as a calligraphy.

  Examples of the iodonium ion include diphenyliodonium, di-p-tolyliodonium, bis (4-dodecylphenyl) iodonium, bis (4-methoxyphenyl) iodonium, (4-octyloxyphenyl) phenyliodonium, and bis (4-decyloxyphenyl). ) Iodonium, 4- (2-hydroxytetradecyloxy) phenylphenyliodonium, 4-isopropylphenyl (p-tolyl) iodonium, isobutylphenyl (p-tolyl) iodonium, and the like, which are described in Macromolecules, 10, 1307 ( 1977), JP-A-6-184170, U.S. Pat. No. 4,256,828, U.S. Pat. No. 4,351,708, JP-A-56-135519, JP-A-58-38350. JP 10-195117, JP 2001-139539, JP 2000-510516 JP, this is described in JP-A-2000-119306.

  Selenium ions include triphenyl selenium, tri-p-tolyl selenium, tri-o-tolyl selenium, tris (4-methoxyphenyl) selenium, 1-naphthyldiphenyl selenium, tris (4-fluorophenyl) selenium, tri-1 -Triaryl selenium such as naphthyl selenium, tri-2-naphthyl selenium, tris (4-hydroxyphenyl) selenium, 4- (phenylthio) phenyl diphenyl selenium, 4- (p-tolylthio) phenyl di-p-tolyl selenium; diphenylphena Diaryl selenium such as silselenium, diphenylbenzyl selenium, diphenylmethyl selenium; phenylmethylbenzyl selenium, 4-hydroxyphenylmethylbenzyl selenium, pheny Monoaryl selenium such as methylphenacyl selenium, 4-hydroxyphenylmethyl phenacyl selenium, 4-methoxyphenylmethyl phenacyl selenium; dimethyl phenacyl selenium, phenacyl tetrahydroselenophenium, dimethylbenzyl selenium, benzyl tetrahydroselenophenium, Examples thereof include trialkyl selenium such as octadecylmethylphenacyl selenium, and these are described in JP-A-50-151997, JP-A-50-151976, JP-A-53-22597, and the like.

  Examples of ammonium ions include tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, tetraethylammonium, trimethyl-n-propylammonium, trimethylisopropylammonium, trimethyl-n-butylammonium, trimethylisobutylammonium, trimethyl- tetraalkylammonium such as t-butylammonium, trimethyl-n-hexylammonium, dimethyldi-n-propylammonium, dimethyldiisopropylammonium, dimethyl-n-propylisopropylammonium, methyltri-n-propylammonium, methyltriisopropylammonium; N, N-dimethylpyrrolidinium, N-ethyl Pyrrolidinium such as N-methylpyrrolidinium, N, N-diethylpyrrolidinium; N, N′-dimethylimidazolinium, N, N′-diethylimidazolinium, N-ethyl-N′-methylimidazolinium 1,2,3-trimethylimidazolinium, 1,3,4-trimethylimidazolinium, 1,3-diethyl-2-methylimidazolinium, 1,3-diethyl-4-methylimidazolinium, , 2,3,4-tetramethylimidazolinium and the like; N, N′-dimethyltetrahydropyrimidinium, N, N′-diethyltetrahydropyrimidinium, N-ethyl-N′-methyltetrahydropyrim Tetrahydropyrimidinium such as midinium, 1,2,3-trimethyltetrahydropyrimidinium; N, N -Morpholinium such as dimethylmorpholinium, N-ethyl-N-methylmorpholinium, N, N-diethylmorpholinium; N, N-dimethylpiperidinium, N-ethyl-N'-methylpiperidinium, Piperidinium such as N, N′-diethylpiperidinium; N-methylpyridinium, N-ethylpyridinium, Nn-propylpyridinium, N-isopropylpyridinium, Nn-butylpyridinium, N-benzylpyridinium, N-phena Pyridiniums such as sylpyridinium; N, N′-dimethylimidazolium, N-ethyl-N-methylimidazolium, N, N′-diethylimidazolium, 1,2-diethyl-3-methylimidazolium, 1,3 -Diethyl-2-methylimidazolium, 1-methyl-3-n-pro Imidazolium such as pill-2,4-dimethylimidazolium; N-methylquinolium, N-ethylquinolium, Nn-propylquinolium, N-isopropylquinolium, Nn-butylquinolium, N- Quinolium such as benzylquinolium, N-phenacylquinolium; N-methylisoquinolium, N-ethylisoquinolium, Nn-propylisoquinolium, N-isopropylisoquinolium, Nn-butyliso Isoquinolium such as quinolium, N-benzylisoquinolium, N-phenacylisoquinolium; thiazonium such as benzylbenzothiazonium and phenacylbenzothiazonium; acridium such as benzylacridium and phenacylacridium It is done.

  These are disclosed in US Pat. No. 4069055, Japanese Patent No. 2519480, Japanese Patent Laid-Open No. 5-222112, Japanese Patent Laid-Open No. 5-222111, Japanese Patent Laid-Open No. 5-262613, Japanese Patent Laid-Open No. 5-255256, JP-A-7-109303, JP-A-10-101718, JP-A-2-268173, JP-A-9-328507, JP-A-5-132461, JP-A-9-216552, JP-A-7 -43854, JP-A-7-43901, JP-A-5-262813, JP-A-4-327574, JP-A-2-43202, JP-A-60-203628, JP-A-57. -209993 and Japanese Patent Laid-Open No. 9-216552.

  Examples of the phosphonium ion include tetraarylphosphonium such as tetraphenylphosphonium, tetra-p-tolylphosphonium, tetrakis (2-methoxyphenyl) phosphonium, tetrakis (3-methoxyphenyl) phosphonium, tetrakis (4-methoxyphenyl) phosphonium; Triarylphosphonium such as triphenylbenzylphosphonium, triphenylphenacylphosphonium, triphenylmethylphosphonium, triphenylbutylphosphonium; triethylbenzylphosphonium, tributylbenzylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, tetrahexylphosphonium, triethylphenacylphosphonium, Tetraalkyl such as tributylphenacylphosphonium Suhoniumu and the like. These are described in JP-A-6-157624, JP-A-5-105692, JP-A-7-82283, JP-A-9-202873, and the like. Examples of bismuthonium ions are described in JP-A-2008-214330.

In the present invention, the charge transporting compound is preferably a polymer or an oligomer from the viewpoints of solubility and film formability.
Moreover, it is preferable that the polymer or oligomer of this invention contains the repeating unit represented by the following general formula (1a)-(84a).

In the formulas (1a) to (84a), each E independently represents —R ¹ , —OR ² , —SR ³ , —OCOR ⁴ , —COOR ⁵ , —SiR ⁶ R ⁷ R ⁸ (where R ¹ to R ⁸ represents a hydrogen atom, a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms, or an aryl group or heteroaryl group having 2 to 30 carbon atoms, where the aryl group is an aromatic group. An atomic group obtained by removing one hydrogen atom from a hydrocarbon, which may have a substituent, and a heteroaryl group is an atomic group obtained by removing one hydrogen atom from an aromatic compound having a hetero atom, It may have a substituent. Ar independently represents an arylene group having 2 to 30 carbon atoms or a heteroarylene group. An arylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon, and may have a substituent, for example, phenylene, biphenyl-diyl, terphenyl-diyl, naphthalene-diyl, anthracene-diyl , Tetracene-diyl, fluorene-diyl, phenanthrene-diyl and the like. The heteroarylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic compound having a hetero atom, and may have a substituent, such as pyridine-diyl, pyrazine-diyl, quinoline-diyl, isoquinoline. -Diyl, acridine-diyl, phenanthroline-diyl, furan-diyl, pyrrole-diyl, thiophene-diyl, oxazol-diyl, oxadiazole-diyl, thiadiazole-diyl, triazole-diyl, benzoxazole-diyl, benzooxadiazole -Diyl, benzothiadiazole-diyl, benzotriazole-diyl, benzothiophene-diyl and the like. X and Z are each independently a divalent linking group, and are not particularly limited. However, a group in which one hydrogen atom is further removed from a group having one or more hydrogen atoms in R is preferable. x represents an integer of 0-2. Y is a trivalent linking group, and represents a group obtained by removing two hydrogen atoms from a group having two or more hydrogen atoms in R.

  The polymer or oligomer preferably has one or more “polymerizable substituents” in order to change the solubility. Here, the “polymerizable substituent” means a substituent capable of forming a bond between two or more molecules by causing a polymerization reaction, and details thereof will be described below.

  Examples of the polymerizable substituent include a group having a carbon-carbon multiple bond (for example, vinyl group, acetylene group, butenyl group, acrylic group, acrylate group, acrylamide group, methacryl group, methacrylate group, methacrylamide group, arene group). , Allyl group, vinyl ether group, vinylamino group, furyl group, pyrrole group, thiophene group, silole group, etc.), a group having a small ring (for example, cyclopropyl group, cyclobutyl group, epoxy group, oxetane group) , Diketene groups, episulfide groups, etc.), lactone groups, lactam groups, or groups containing siloxane derivatives. In addition to the above groups, combinations of groups capable of forming an ester bond or an amide bond can also be used. For example, a combination of an ester group and an amino group, an ester group and a hydroxyl group, or the like. As the polymerizable substituent, an oxetane group, an epoxy group, a vinyl group, a vinyl ether group, an acrylate group, and a methacrylate group are particularly preferable from the viewpoint of reactivity, and an oxetane group is particularly preferable.

  In addition, the polymer or oligomer that forms the polymerization layer in the present invention is not limited to the above repeating unit, in addition to the above repeating unit, the above arylene group, heteroarylene group, or general formula (1a) to (1) to adjust the solubility, heat resistance, and electrical characteristics. The copolymer which has a structure represented by (84a) as a copolymer repeating unit may be sufficient. In this case, the copolymer may be a random, block or graft copolymer, or may be a polymer having an intermediate structure thereof, for example, a random copolymer having a block property. In addition, the polymer or oligomer used in the present invention may have branching in the main chain and may have three or more terminals.

The charge transport film in the present invention preferably contains a polymerization initiator.
The polymerization initiator is not particularly limited as long as it exhibits the ability to polymerize a polymerizable substituent by application of heat, light, microwave, radiation, electron beam, and the like. Or it is preferable to start polymerization by heating.

  The ratio of the polymerization initiator in the charge transport film in the present invention is not particularly limited as long as the polymerization is sufficiently advanced, and is preferably 0.1% by mass to 50% by mass. When the amount is less than this, polymerization does not proceed efficiently, and the solubility cannot be changed sufficiently. On the other hand, when the amount is larger than this, a large amount of the polymerization initiator and / or decomposition product remains, and the effect of washing becomes low.

  Further, in addition to the initiator, a sensitizer for improving photosensitivity and / or heat sensitivity may be included. Further, from the viewpoint of imparting a charge transportability improving function and a polymerization initiating function, the polymerization initiator in the present invention is preferably the above ionic compound.

Furthermore, this invention contains the cleaning agent which can be used for the said washing | cleaning process. Furthermore, the cleaning agent preferably contains a basic compound.
Here, in the present invention, as the “basic compound”, any known one can be used, but representative examples include basic alkali metal compounds, basic alkaline earth metal compounds, amines and the like. Organic compounds and the like.

  Examples of the basic alkali metal compounds include alkali metal hydroxides (lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.), alkali metal carbonates (lithium carbonate, sodium carbonate, potassium carbonate, etc.), alkali metals. Alcoholate (sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, etc.).

  Examples of the basic alkaline earth metal compound include alkaline earth metal hydroxides (magnesium hydroxide, calcium hydroxide, etc.), alkaline earth metal carbonates (magnesium carbonate, calcium carbonate, etc.), alkalis, and the like. Examples include earth metal alcoholates (magnesium methoxide, etc.).

  Examples of the basic organic compound include amines and nitrogen-containing heterocyclic compounds such as quinoline and quinolidine, among which amines are preferable, for example, alkylamines such as methylamine, ethylamine and butylamine, dimethylamine, diethylamine, Dialkylamines such as dibutylamine, trialkylamines such as trimethylamine, triethylamine and tributylamine, arylamines such as aniline and naphthylamine, diarylamines such as diphenylamine and dinaphthylamine, triphenylamine, quinuclidine, ethylenediamine, tetramethylethylenediamine, hexamethylene Diamine, hexamethylenetetramine, triethanolamine and their derivatives, and polymers or chains containing these sites in the chain It may be an oligomer.

The detergent used in the present invention preferably contains a basic compound and a solvent.
In the present invention, the solvent contained in the cleaning agent may be the same compound as the basic compound, and is not particularly limited as long as it can sufficiently dissolve the basic compound. Are water, alcohols such as methanol, ethanol, isopropyl alcohol, alkanes such as pentane, hexane and octane, cyclic alkanes such as cyclohexane, aromatic solvents such as benzene, toluene, xylene, mesitylene, tetralin and diphenylmethane, ethylene glycol dimethyl ether, Aliphatic ethers such as ethylene glycol diethyl ether and propylene glycol-1-monomethyl ether acetate, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4 Aromatic ethers such as methoxytoluene, 2,3-dimethylanisole and 2,4-dimethylanisole, aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate, phenyl acetate, phenyl propionate, Aromatic esters such as methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, and others, dimethyl sulfoxide, tetrahydrofuran, acetone , Chloroform, methylene chloride and the like, and aromatic solvents are preferred.

  In the cleaning step of the production method of the present invention, the substrate on which the polymer layer is formed may be cleaned by immersing it in a cleaning agent, or may be cleaned by spraying a cleaning solution on the substrate, etc., and a cleaning effect is expected. There is no particular limitation as long as it can be performed.

  Furthermore, the organic thin film of the present invention is formed using the method for producing an organic thin film described above. Furthermore, this invention is an organic electronics element which has the said organic thin film. Furthermore, this invention is an organic electroluminescent element which has the said thin film.

[Organic EL device]
The organic electroluminescent device (organic EL device) of the present invention is characterized by having a polymerized layer formed using the method for producing an organic thin film of the present invention. The organic EL device of the present invention is not particularly limited as long as it includes a light emitting layer, a polymerized layer, an anode, a cathode, and a substrate. Other elements such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer are used. It may have a layer. Hereinafter, each layer will be described in detail.

[Light emitting layer]
The material used for the light emitting layer may be a low molecular compound, a polymer or an oligomer, and a dendrimer or the like can also be used. Examples of low molecular weight compounds that utilize fluorescence include perylene, coumarin, rubrene, quinacudrine, dye laser dyes (eg, rhodamine, DCM1, etc.), aluminum complexes (eg, Tris (8-hydroxyquinolinato) aluminum (III) (Alq ₃ )), Stilbene, and derivatives thereof. Polymers or oligomers that utilize fluorescence include polyfluorene, polyphenylene, polyphenylene vinylene (PPV), polyvinyl carbazole (PVK), fluorene-benzothiadiazole copolymer, fluorene-triphenylamine copolymer, and derivatives thereof. And a mixture can be suitably used.

  On the other hand, in recent years, phosphorescent organic EL devices have been actively developed in order to increase the efficiency of organic EL devices. In the phosphorescent organic EL element, not only singlet state energy but also triplet state energy can be used, and the internal quantum yield can be increased to 100% in principle. In the phosphorescent organic EL element, phosphorescence is extracted by doping a host material with a metal complex phosphorescent material containing a heavy metal such as platinum or iridium as a dopant that emits phosphorescence (see Non-Patent Documents 5 to 7).

Also in the organic EL device of the present invention, it is preferable to use a phosphorescent material for the light emitting layer from the viewpoint of high efficiency. As the phosphorescent material, a metal complex containing a central metal such as Ir or Pt can be preferably used. Specifically, as an Ir complex, for example, FIr (pic) [iridium (III) bis [(4,6-difluorophenyl) -pyridinate-N, C ² ] picolinate] that emits blue light and green light are emitted. Ir (ppy) ₃ [Factris (2-phenylpyridine) iridium] (see Non-Patent Document 5) or Adachi et al. , Appl. Phys. Lett. 78, no. (Btp) ₂ Ir (acac) {bis [2- (2′-benzo [4,5-α] thienyl) pyridinate-N, C3] iridium (acetyl-acetonate) which emits red light as shown in 11,2001, 1622 )}, Ir (piq) ₃ [Tris (1-phenylisoquinoline) iridium] and the like.

Examples of the Pt complex include 2,3,7,8,12,13,17, 18-octaethyl-21H, 23H-forminplatinum (PtOEP) that emits red light.
The phosphorescent material can be a small molecule or a dendrite species, such as an iridium nucleus dendrimer. Moreover, these derivatives can also be used conveniently.

Further, in the case where a phosphorescent material is included in the light emitting layer, it is preferable that a host material is included in addition to the phosphorescent material.
The host material may be a low molecular compound or a high molecular compound, and a dendrimer or the like can also be used.

  Examples of the low molecular weight compound include CBP (4,4′-Bis (Carbazol-9-yl) -biphenyl), mCP (1,3-bis (9-carbazolyl) benzene), CDBP (4,4′-Bis). (Carbazol-9-yl) -2,2′-dimethylbiphenyl) and the like, for example, polyvinyl carbazole, polyphenylene, polyfluorene and the like can be used, and derivatives thereof can also be used.

The light emitting layer may be formed by a vapor deposition method or a coating method.
When forming by the apply | coating method, an organic EL element can be manufactured cheaply and it is more preferable. In order to form a light emitting layer by a coating method, a solution containing a phosphorescent material and, if necessary, a host material is used, for example, an ink jet method, a casting method, a dipping method, a relief printing, an intaglio printing, an offset printing, a flat printing, a relief printing. It can be carried out by applying on a desired substrate by a known method such as a printing method such as reverse offset printing, screen printing or gravure printing, or spin coating method.

[cathode]
The cathode material is preferably a metal or metal alloy such as Li, Ca, Mg, Al, In, Cs, Ba, Mg / Ag, LiF, and CsF.

[anode]
As the anode, a metal (for example, Au) or other material having metal conductivity, for example, an oxide (for example, ITO: indium oxide / tin oxide), a conductive polymer (for example, a polythiophene-polystyrene sulfonic acid mixture (for example, PEDOT: PSS)) can also be used.

[Electron transport layer, electron injection layer]
Examples of the electron transport layer and the electron injection layer include a phenanthroline derivative (for example, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)), a bipyridine derivative, a nitro-substituted fluorene derivative, and a diphenylquinone derivative. , Thiopyrandioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives (2- (4-Biphenylyl) -5 (4-tert-butylphenyl-1,3,4-oxadiazole) (PBD)), aluminum complexes (eg, Tris (8-hydroxyquinolinato) aluminum (II ) _(Alq 3)) and the like. Furthermore, in the oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can be used.

[substrate]
As the substrate that can be used in the organic EL device of the present invention, the kind of glass, plastic and the like is not particularly limited, and is not particularly limited as long as it is transparent, but glass, quartz, light transmissive A resin film or the like is preferably used. When a resin film is used, flexibility can be given to the organic EL element, which is particularly preferable.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose triacetate. Examples thereof include films made of (TAC), cellulose acetate propionate (CAP) and the like.

  Moreover, when using a resin film, in order to suppress permeation | transmission of water vapor | steam, oxygen, etc., you may coat and use inorganic substances, such as a silicon oxide and silicon nitride, on a resin film.

[Luminescent color]
The emission color in the organic EL device of the present invention is not particularly limited, but the white light-emitting device is preferable because it can be used for various lighting devices such as home lighting, interior lighting, clocks, and liquid crystal backlights.

  As a method of forming a white light emitting element, since it is currently difficult to show white light emission with a single material, a plurality of light emitting colors can be simultaneously emitted and mixed using a plurality of light emitting materials. White luminescence is obtained. A combination of a plurality of emission colors is not particularly limited. However, a combination of three emission maximum wavelengths of blue, green, and red, a complementary color relationship such as blue and yellow, yellow green and orange is used. The thing containing two light emission maximum wavelengths is mentioned. The emission color can be controlled by adjusting the type and amount of the phosphorescent material.

  The method for producing a thin film of the present invention can be used for forming a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like of an organic electronic device. It is preferably used for forming a hole injection layer, a hole transport layer, and a light emitting layer of an EL element.

In order to produce an organic EL element or the like using the method for producing a thin film of the present invention, for example, an inkjet method, a casting method, a dipping method, letterpress printing, intaglio printing, offset printing, lithographic printing, letterpress reverse offset printing, screen printing. The polymer layer can be formed by forming a polymer layer on a desired substrate by a known method such as a gravure printing method, a spin coating method, light irradiation or heat treatment, and then washing the polymer layer. By this work, it becomes possible to produce an organic electronics element or an organic EL element in which the influence of the polymerization initiator and / or its decomposition product is reduced.
The washing step of the method for producing a thin film of the present invention can be usually carried out at a temperature range of -20 to + 300 ° C, preferably 10 to 100 ° C, particularly preferably 15 to 50 ° C.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited to these Examples.
<Synthesis of monomer>
(Monomer Synthesis Example 1)
As shown in the following reaction formula, in a round bottom flask, 3-ethyl-3-hydroxymethyloxetane (50 mmol), 4-bromobenzyl bromide (50 mmol), n-hexane (200 mL), tetrabutylammonium bromide (2.5 mmol). ) And 50% by mass aqueous sodium hydroxide solution (36 g), and the mixture was stirred with heating at 70 ° C. for 6 hours under nitrogen.

  After cooling to room temperature (25 ° C.), 200 mL of water was added and extracted with n-hexane. After the solvent was distilled off, the residue was purified by silica gel column chromatography and reduced pressure distillation to obtain 9.51 g of monomer A having a polymerizable substituent as a colorless oil. The yield is 67% by mass. Moreover, the NMR analysis result of the synthesized monomer A is shown below.

1H-NMR (300 MHz, CDCl ₃ , δ ppm); 0.86 (t, J = 7.5 Hz, 3H), 1.76 (t, J = 7.5 Hz, 2H), 3.57 (s, 2H) , 4.39 (d, J = 5.7 Hz, 2H), 4.45 (d, J = 5.7 Hz, 2H), 4.51 (s, 2H), 7.22 (d, J = 8. 4 Hz, 2H), 7.47 (d, J = 8.4 Hz, 2H).

<Synthesis of charge transporting compound>
(Synthesis Example 1)
As shown in the following reaction formula, 2,7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -9,9 is placed in a sealable fluororesin container. -Dioctylfluorene (0.4 mmol), 4,4'-dibromo-4'-n-butyltriphenylamine (0.32 mmol), monomer A having a polymerizable substituent (0.16 mmol), tetrakistriphenylphosphine Palladium (0.008 mmol), 2M aqueous potassium carbonate solution (5.3 ml), Aliquat 336 (0.4 mmol) and anisole (4 ml) were added, and microwave irradiation was performed in a sealed container at 90 ° C. for 2 hours under a nitrogen atmosphere. Stir with heating.

  The reaction solution was poured into a methanol / water mixed solvent (9: 1), and the precipitated polymer was filtered off. The reprecipitation was repeated twice to purify, and thus an oligomer A having a polymerizable substituent and a repeating unit having a hole transporting property was obtained. The number average molecular weight of the obtained oligomer A was 4652 in terms of polystyrene.

<Production of organic EL element>
[Example 1]
A PEDOT: PSS dispersion (Stark Vitec, AI4083 LVW142) was spin-coated at 1500 min ⁻¹ on a glass substrate patterned with ITO to a width of 1.6 mm, and 200 ° C./10 minutes in air on a hot plate. A hole injection layer (40 nm) was formed by heating and drying. Subsequent experiments were performed in a dry nitrogen environment.

Next, a coating solution in which the oligomer A (4.5 mg) obtained above, a photoinitiator (0.45 mg) represented by the following chemical formula, and toluene (1.2 ml) were mixed on the hole injection layer was 3000 min ^−. After spin coating at ¹ , the film was cured by heating at 180 ° C. for 10 minutes on a hot plate to form a hole transport layer (40 nm). The substrate was immersed in toluene (50 ml) and washed by shaking for 10 seconds.

Next, the obtained glass substrate was transferred into a vacuum evaporator, and CBP + Ir (piq) ₃ (40 nm), BAlq (10 nm), Alq ₃ (30 nm), LiF (film thickness 0.5 nm), Al (film thickness 100 nm) ).

  After electrode formation, the substrate is moved into a dry nitrogen environment without opening to the atmosphere, and the sealing glass and ITO substrate in which 0.4 mm of counterbore is added to 0.7 mm non-alkali glass are coated with a photocurable epoxy resin. Sealing was performed by using them together to produce a polymer organic EL device having a multilayer structure. Subsequent experiments were performed in the atmosphere at room temperature (25 ° C.).

When voltage was applied using ITO as the positive electrode and Al as the cathode of the organic EL element, red light emission was observed at 3.5V. At a luminance of 1000 cd / m ^2, the current efficiency was 5.50 cd / A and the power efficiency was 2.19 lm / W. The current-voltage characteristics were measured using a microammeter 4140B manufactured by Hewlett-Packard Co., Ltd., and the luminance was measured using a luminance meter Richard 1980B manufactured by Photo Research Co., Ltd.
In addition, as a lifetime characteristic, the luminance was measured with BM-7 manufactured by Topcon Corporation while applying a constant current, and the time for the luminance to be halved from the initial luminance (1000 cd / m ² ) was measured, and it was 60 hours.

[Example 2]
An organic EL device was produced in the same manner as in Example 1 except that the solution used in the washing step after forming the hole transport layer was changed to a 0.5 mass% toluene solution (50 ml) of triethylamine. When voltage was applied to the organic EL element, red light emission was observed at 3.5 V, the current efficiency at a luminance of 1000 cd / m ² was 8.03 cd / A, and the power efficiency was 2.98 lm / W. When the lifetime characteristics were measured, the luminance was reduced by half in 101 hours.

[Comparative Example 1]
An organic EL device was produced in the same manner as in Example 1 except that the cleaning step was not performed after forming the hole transport layer. When voltage was applied to this organic EL element, red light emission was observed at 3.5 V, the current efficiency at a luminance of 1000 cd / m ² was 4.87 cd / A, and the power efficiency was 1.91 lm / W. Further, when the lifetime characteristics were measured, the luminance was reduced by half in 46 hours.

  From comparison between Examples 1 and 2 and Comparative Example 1, it can be seen that the organic EL element of the Example is superior to Comparative Example 1 in any of current efficiency, power efficiency, and light emission lifetime. This is because the rinsing liquid and the cleaning step in the present invention are applied to the organic EL device manufacturing step, the amount of the remaining ionic compound and / or its decomposition product is reduced, the luminous efficiency is improved, and the luminous lifetime is long. It is thought that it has become.

<Production of white organic EL element and lighting device>
[Example 3]
In the same manner as in Example 1, a hole injection layer (40 nm) was formed using PEDOT: PSS dispersion, and a hole transport layer was formed using oligomer A and a photoinitiator (same as Example 1). The substrate was immersed in toluene (50 ml) and washed by shaking for 10 seconds.

Next, in nitrogen, CDBP (15 mg), FIr (pic) (0.9 mg), Ir (ppy) 3 (0.9 mg), (btp) 2Ir (acac) (1.2 mg), dichlorobenzene (0. 5 mL) was spin-coated at 3000 rpm and then dried at 80 ° C. for 5 minutes to form a light emitting layer (40 nm). Further, in the same manner as in Example 1, BAlq (10 nm), Alq ₃ (30 nm), LiF (film thickness: 0.5 nm), Al (film thickness: 100 nm) were vapor-deposited in this order, sealed, and subjected to an organic EL element and A lighting device was produced.
When voltage was applied to the white organic EL element and the lighting device, uniform white light emission was observed.

[Comparative Example 2]
A white organic EL element and a lighting device were produced in the same manner as in Example 3 except that the hole transport layer washing step was not performed.
When voltage was applied to the white organic EL element and the illumination device, white light emission was observed, but the light emission lifetime was 1/3 that of Example 3.

  From the comparison between Example 3 and Comparative Example 2 described above, it can be seen that the white organic EL element and the lighting device can be stably driven by inserting the cleaning step in the present invention.

DESCRIPTION OF SYMBOLS 1 Light emitting layer 2 Anode 3 Hole injection layer 4 Cathode 5 Electron injection layer 6 Hole transport layer 7 Electron transport layer 8 Substrate

Claims (9)

In a method for producing an organic thin film having a laminated structure, a thin film (hereinafter referred to as a charge transport film) formed using a compound having a charge transport unit (hereinafter referred to as a charge transport compound) and an ionic compound is used. A step of cleaning (hereinafter referred to as a cleaning step), and a step of forming a thin film on the thin film,
A method for producing an organic thin film, wherein a cleaning agent is used in the cleaning step, and the cleaning agent contains a basic compound.   The method for producing an organic thin film according to claim 1, wherein the charge transporting unit is an aromatic amine unit, a carbazole unit, or a thiophene unit.   The method for producing an organic thin film according to claim 1 or 2, wherein the ionic compound is an onium salt.   The method for producing an organic thin film according to any one of claims 1 to 3, wherein the charge transporting compound is a polymer or an oligomer.   The method for producing an organic thin film according to claim 4, wherein the polymer or oligomer has one or more polymerizable substituents.   6. The method for producing an organic thin film according to claim 5, wherein the polymerizable substituent is any one of an oxetane group, an epoxy group, a vinyl group, a vinyl ether group, an acrylate group, or a methacrylate group.   The method for producing an organic thin film according to claim 1, wherein the charge transport film is formed using a polymerization initiator.   8. The method for producing an organic thin film according to claim 7, wherein the charge transport film is formed using an ionic compound as a polymerization initiator.   The method for producing an organic thin film according to any one of claims 1 to 8, wherein the cleaning agent further contains a solvent.

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