JP4789598B2 - LIGHT EMITTING ELEMENT AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to a light-emitting element that emits light by current excitation, and particularly relates to a layer structure.

  A light-emitting element having a layer containing a light-emitting substance between a pair of electrodes is used as a pixel, a light source, or the like, and is provided in a light-emitting device such as a display device or a lighting device. In such a light emitting device, the reliability of the light emitting element is closely related to the performance of the light emitting device. For example, when a short circuit occurs between the electrodes of the light emitting element, the display image is disturbed or a sufficient amount of light cannot be illuminated.

  Therefore, in recent years, development of a light emitting element that has few element defects and can stably emit light for a long period of time has been advanced. For example, Patent Document 1 discloses a technique for manufacturing a light-emitting element that operates at a low driving voltage by using a metal oxide having a high work function such as molybdenum oxide for an anode. In addition, the effect of extending the life is obtained.

JP-A-9-63771

  It is an object of the present invention to provide a light-emitting element with less malfunction due to crystallization of a layer provided in the light-emitting element, a light-emitting device using the light-emitting element, and an electronic device.

  One light-emitting element of the present invention includes a mixed layer including a metal oxide and a compound that exhibits an electron donating property with respect to the metal oxide. This layer is provided with a first region and a second region. The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region. Further, the first area and the second area are alternately and repeatedly provided. The first region and the second region each have a distance of 0.1 nm to 10 nm, more preferably 1 nm to 5 nm, in the thickness direction of the mixed layer. Here, the molar ratio (= metal oxide / compound) of the metal oxide to the compound exhibiting electron donating property with respect to the metal oxide is 0.1 or more and 10 or less (average value in the entire mixed layer). It is preferable that each of the compound and metal oxide which show an electron donating property with respect to a metal oxide is contained.

  One light-emitting element of the present invention includes a mixed layer including a metal oxide, a first compound, and a second compound. The first compound exhibits an electron donating property to the metal oxide. The LUMO level of the second compound is lower than the LUMO level of the first compound. This layer is provided with a first region and a second region. The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region. Further, the first area and the second area are alternately and repeatedly provided. The first region and the second region each have a distance of 0.1 nm to 10 nm, more preferably 1 nm to 5 nm, in the thickness direction of the mixed layer. Here, the first compound so that the molar ratio of the metal oxide to the first compound (= metal oxide / first compound) is 0.1 or more and 10 or less (average value in the entire mixed layer). And each of the metal oxides is preferably contained.

  One light-emitting element of the present invention includes a composite layer including a metal atom, an oxygen atom, and a compound that exhibits an electron donating property with respect to the metal atom, and the metal atom is bonded to the oxygen atom. The composite layer has a first region and a second region. The first region and the second region are alternately and repeatedly provided, and the concentration of metal atoms contained in the first region is higher than the concentration of metal atoms contained in the second region. Each of the first region and the second region has a distance of 0.1 nm to 10 nm, more preferably 1 nm to 5 nm in the thickness direction of the composite layer. Here, the molar ratio of the metal atom to the compound that exhibits an electron donating property with respect to the metal atom (= metal atom / compound) is 0.1 to 10 (average value in the entire composite layer). It is preferable that the compound and metal atom which show an electron donating property are contained.

  One light-emitting element of the present invention has a composite layer including a metal atom, an oxygen atom, a first compound, and a second compound. In this composite layer, metal atoms are bonded to oxygen atoms. And a 1st compound shows an electron donating property with respect to a metal atom. The LUMO level of the second compound is lower than the LUMO level of the first compound. The composite layer is provided with a first region and a second region, and the concentration of metal atoms contained in the first region is higher than the concentration of metal atoms contained in the second region. Further, the first area and the second area are alternately and repeatedly provided. The first region and the second region each have a distance of 0.1 nm to 10 nm, more preferably 1 nm to 5 nm, in the thickness direction of the composite layer. Here, the first compound and the metal so that the molar ratio of the metal atom to the first compound (= metal atom / first compound) is 0.1 or more and 10 or less (average value in the entire composite layer). Preferably atoms are included.

  By implementing the present invention, a light-emitting element with less malfunction due to crystallization of a layer provided in the light-emitting element can be obtained. In addition, by implementing the present invention, a light-emitting element having a long element lifetime can be obtained.

  Since the light-emitting element used in the practice of the present invention has few malfunctions due to crystallization of the layers provided in the light-emitting element, a light-emitting device with few display defects due to defects in the light-emitting element can be achieved by implementing the present invention. Obtainable.

  Since the light-emitting device used for carrying out the present invention uses a light-emitting element with few malfunctions due to crystallization, there are few display defects and the like. Therefore, by implementing the present invention, it is possible to obtain an electronic device in which there is little misidentification of an image due to display failure in the light emitting device and accurate information can be transmitted to the user through the display image.

  Hereinafter, one embodiment of the present invention will be described. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of the embodiment.

(Embodiment 1)
One mode of a light-emitting element of the present invention will be described with reference to FIG.

  FIG. 1A illustrates a light-emitting element having a layer containing a light-emitting substance between the first electrode 101 and the second electrode 102. In this embodiment mode, the layer containing a light-emitting substance is formed by stacking a plurality of layers, and in addition to the light-emitting layer 113, a hole generation layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115 are provided. ing. The light emitting material is included in the light emitting layer 113 in particular. When voltage is applied to the first electrode 101 and the second electrode 102 so that the potential of the first electrode 101 is higher than the potential of the second electrode 102, the light-emitting layer 113 has the first electrode Holes are injected from the 101 side, and electrons are injected from the second electrode 102 side. Then, the holes and electrons injected into the light emitting layer 113 are recombined. The light-emitting layer 113 contains a light-emitting substance, and the light-emitting substance is excited by excitation energy generated by recombination. The luminescent material in the excited state emits light when returning to the ground state.

The hole generation layer 111 includes a first region 111a and a second region 111b (FIG. 1B). The number of metal atoms contained in the first region 111a is larger than the number of metal atoms contained in the second region 111b. The first region 111a and the second region 111b are provided so as to be alternately repeated. The first region 111a and the second region 111b each preferably have a distance of 0.1 nm to 10 nm in the thickness direction, and more preferably have a distance of 1 nm to 5 nm. Preferably (that is, the distance d ₁ between one second region 111b and the other second region 111b of the two second regions 111b adjacent to the first region 111a is not less than 0.1 nm and not more than 10 nm. Preferably 1 nm or more and 5 nm or less). In other words, the region where the metal atom concentration is high (the first region 111a) in the hole generation layer 111 is periodically provided with an interval of 0.1 nm to 10 nm (more preferably 1 nm to 5 nm). It has been. In the hole generation layer 111 in which metal atoms are distributed in this way, the metal atoms are bonded to oxygen atoms. Note that the number of repetitions of the first region 111a and the second region 111b is not particularly limited.

  Here, the metal atom is preferably a metal atom belonging to Groups 4 to 8 of the periodic table of elements such as vanadium, molybdenum, rhenium, and ruthenium. Other examples of the metal atom belonging to Groups 4 to 8 of the periodic table include titanium, zirconium, hafnium, tantalum, chromium, tungsten, manganese, osmium, and the like.

  The hole generating layer 111 contains the first compound. The first compound is a compound including a structure in which a metal atom and an oxygen atom are bonded (for example, as such a compound, 4 in the periodic table of elements such as molybdenum oxide, vanadium oxide, rhenium oxide, and ruthenium oxide). An oxide of a metal belonging to Group 8 to Group 8). In addition, a charge transfer complex may be produced | generated by showing electron donating property.

  Examples of the first compound that can be used in the practice of the present invention include aromatic amine-based compounds containing a triphenylamine structure. Specific examples of aromatic amine compounds include 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4′-bis [N- (3-methylphenyl). ) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″- Tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis {N- [4- (N, N-di-m-tolylamino) phenyl] -N-phenylamino} biphenyl (abbreviation: DNTPD), 1,3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), 4,4 ', 4' ' -Tris (N-carbazo Le) triphenylamine (abbreviation: TCTA) and the like. These are substances having a higher hole mobility than electrons and a ratio of the hole mobility to the electron mobility (= hole mobility / electron mobility) greater than 100, so-called monopolar properties. It is a substance and is a substance having a particularly high hole transporting property among monopolar substances. In addition to the monopolar substance shown here, a bipolar substance such as 2,3-bis (4-diphenylaminophenyl) quinoxaline (abbreviation: TPAQn) may be used. Here, the bipolar substance is the mobility of one carrier with respect to the mobility of the other carrier when the mobility of one of electrons or holes is compared with the mobility of the other carrier. A ratio value of 100 or less, preferably 10 or less.

  Moreover, it is preferable that the hole generation layer 111 further contains a second compound. The second compound is preferably a compound having a lower lowest unoccupied molecular orbital (LUMO) level than the first compound. In this manner, by further including the second compound, it is possible to prevent the first compound from being deteriorated due to the generated carriers and to extend the lifetime of the light emitting element. Specific examples of the second compound include rubrene, copper phthalocyanine, 4-dicyanomethylene-2-isopropyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl]- 4H-pyran (abbreviation: DCJTI), 4-dicyanomethylene-2-tert-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran ( Abbreviations: DCJTB), N, N′-dimethylquinacridone (abbreviation: DMQd), N, N′-diphenylquinacridone (abbreviation: DPQd), coumarin 6 and the like.

  In the hole generation layer 111, the molar ratio of the metal atom to the first compound (= metal atom / first compound) is 0.1 or more and 10 or less, more preferably 0.5 or more and 5 or less. The first compound and the metal atom are preferably contained. In the hole-generating layer 111, the molar ratio of the second compound to the first compound (= second compound / first compound) is 0.005 or more and 0.1 or less, more preferably 0.01. It is preferable that the ratio is 0.08 or less (the molar ratio described here is an average value of the whole hole generation layer 111).

  The hole generation layer 111 having the above-described configuration can generate holes. Therefore, even when it is difficult to inject holes from the first electrode 101, the holes can be stably transported to the light emitting layer 113 by providing the hole generation layer 111. Further, the hole generation layer 111 having the above-described configuration is hardly crystallized and has good stability.

  The light emitting layer 113 contains a light emitting substance. Here, the light-emitting substance is a substance that has good emission efficiency and can emit light of a desired wavelength. The light-emitting layer 113 may be a layer formed only of a light-emitting substance, but when concentration quenching occurs, the light-emitting substance is contained in a layer formed of a substance having an energy gap larger than that of the light-emitting substance. A layer mixed so as to be dispersed is preferable. By including a light-emitting substance in the light-emitting layer 113 in a dispersed manner, light emission can be prevented from being quenched due to concentration. Here, the energy gap refers to an energy gap between the LUMO level and the HOMO level.

There is no particular limitation on the light-emitting substance, and a substance that has favorable emission efficiency and can emit light with a desired emission wavelength may be used. For example, to obtain red light emission, 4-dicyanomethylene-2-isopropyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran ( Abbreviation: DCJTI), 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJT), 4 -Dicyanomethylene-2-tert-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), periflanthene, 2,5 -Dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] benzene, etc., emission spectrum from 600 nm to 680 nm Substance which exhibits emission with a peak can be used as a light-emitting substance. When green light emission is desired, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), etc., emits light from 500 nm to 550 nm. A substance that emits light having a spectral peak can be used as the light-emitting substance. When blue light emission is desired, 9,10-bis (2-naphthyl) -tert-butylanthracene (abbreviation: t-BuDNA), 9,9′-bianthryl, 9,10-diphenylanthracene (abbreviation) : DPA), 9,10-bis (2-naphthyl) anthracene (abbreviation: DNA), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (abbreviation: BGaq), bis (2-methyl) A substance exhibiting light emission having an emission spectrum peak at 420 nm to 500 nm, such as -8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), can be used as the light-emitting substance. As described above, in addition to a substance that emits fluorescence, bis [2- (3,5-bis (trifluoromethyl) phenyl) pyridinato-N, C ^{2 ′} ] iridium (III) picolinate (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), bis [2- (4,6-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) acetylacetonate (abbreviation: FIr (acac)), bis [2- (4 , 6-Difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) picolinate (abbreviation: FIr (pic)), tris (2-phenylpyridinato-N, C ^{2 ′} ) iridium (abbreviation: Ir (ppy) ₃ ) A phosphorescent substance such as ₃ ) can also be used as the light emitting substance.

There is no particular limitation on a substance that is included in the light-emitting layer 113 together with the light-emitting substance and is used for dispersing the light-emitting substance, and may be appropriately selected in consideration of an energy gap of the substance used as the light-emitting substance. For example, anthracene derivatives such as 9,10-di (2-naphthyl) -2-tert-butylanthracene (abbreviation: t-BuDNA), or 4,4′-bis (N-carbazolyl) biphenyl (abbreviation: CBP) Carbazole derivatives of 2,3-bis (4-diphenylaminophenyl) quinoxaline (abbreviation: TPAQn), 2,3-bis {4- [N- (1-naphthyl) -N-phenylamino] phenyl} -dibenzo [ In addition to quinoxaline derivatives such as f, h] quinoxaline (abbreviation: NPDiBzQn), bis [2- (2-hydroxyphenyl) pyridinato] zinc (abbreviation: Znpp ₂ ), bis [2- (2-hydroxyphenyl) benzoxazola G] A metal complex such as zinc (abbreviation: ZnBOX) or the like can be used together with a light-emitting substance.

It is preferable to provide a hole transport layer 112 between the light emitting layer 113 and the hole generation layer 111 as shown in FIG. The hole transport layer 112 has a function of transporting holes, and has a function of transporting holes injected from the first electrode 101 side to the light emitting layer 113. By providing the hole transport layer 112 in this manner, the distance between the hole generation layer 111 and the light emitting layer 113 can be increased. As a result, light emission is caused by the metal contained in the hole generation layer 111. Can be prevented from quenching. The hole-transport layer 112 is preferably formed using a substance having a high hole-transport property, and particularly preferably formed using a substance having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. . Examples of the substance having a high hole transporting property include NPB, TPD, TDATA, MTDATA, DNTPD, m-MTDAB, TCTA, and the like.

An electron transport layer 114 is preferably provided between the light emitting layer 113 and the second electrode 102 as shown in FIG. The electron-transport layer 114 is a layer having a function of transporting electrons. In the light-emitting element of this embodiment mode, the electron-transport layer 114 has a function of transporting electrons injected from the second electrode 102 side to the light-emitting layer 113. By providing the electron transport layer 114, the distance between the second electrode 102 and the light-emitting layer 113 can be increased, and as a result, light emission is quenched due to the metal contained in the second electrode 102. Can be prevented. Similarly, in the case where a metal is included in the electron injection layer 115, quenching due to the metal can be prevented by providing the electron transport layer 114 and increasing the distance between the electron injection layer 115 and the light emitting layer 113. I can do it. The electron transport layer 114 is preferably formed using a substance having a high electron transport property, and particularly preferably formed using a substance having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that a substance having a high electron-transport property has higher electron mobility than holes, and the ratio of the electron mobility to the hole mobility (= electron mobility / hole mobility) is 100 or more. Also refers to a large substance. Specific examples of a substance that can be used for forming the electron-transport layer 114 include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq _3). ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), bis [2- In addition to metal complexes such as (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ) 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (approximately) Name: PBD), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4- tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 4,4-bis (5-methylbenzoxa) Sol-2-yl) stilbene (BzOs) and the like.

Note that the hole transport layer 112 and the electron transport layer 114 may be formed using a bipolar substance such as TPAQn, in addition to the monopolar substance as described above. Among bipolar substances, it is particularly preferable to use a substance having a hole and electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or more. Alternatively, the hole transport layer 112 and the electron transport layer 114 may be formed using the same bipolar substance.

  Further, an electron injection layer 115 may be provided between the electron transport layer 114 and the second electrode 102. The electron injection layer 115 is a layer having a function of assisting injection of electrons from the second electrode 102 to the electron transport layer 114. By providing the electron injection layer 115, the difference in electron affinity between the second electrode 102 and the electron transport layer 114 is reduced, and electrons are easily injected. The electron injection layer 115 is a substance having a higher electron affinity than the substance forming the electron transport layer 114 and a lower electron affinity than the substance forming the second electrode 102, or the electron transport layer 114 and the second transport layer 114. It is preferable to use a substance whose energy band is bent when it is provided as a 1 to 2 nm thin film between the electrode 102 and the electrode 102. Examples of materials that can be used to form the electron injecting layer 115 include alkali metals or alkaline earth metals, alkali metal fluorides, alkaline earth metal fluorides, alkali metal oxides, alkaline earth metals And inorganic materials such as oxides of More specifically, lithium oxide, magnesium oxide, lithium fluoride, calcium fluoride and the like can be mentioned. In addition to inorganic substances, substances that can be used to form the electron transport layer 114 such as BPhen, BCP, BCP, p-EtTAZ, TAZ, and BzOs are also used to form the electron transport layer 114 from these substances. By selecting a substance having an electron affinity higher than that of the substance to be used, the substance can be used as a substance for forming the electron injection layer 115. That is, the electron injection layer 115 can be formed by selecting a substance that has an electron affinity in the electron injection layer 115 larger than that in the electron transport layer 114.

  Further, an electron generation layer may be provided instead of the electron injection layer. The electron generating layer includes an electron-donating substance such as an alkali metal or alkaline earth metal, an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal oxide, or an alkaline earth metal oxide; It can be formed by mixing a substance having a high electron accepting property.

  The first electrode 101 is made of indium tin oxide, indium tin oxide containing silicon oxide, indium oxide containing zinc oxide, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium. (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), a material having a high work function such as tantalum nitride, aluminum, You may form using substances with a low work function, such as magnesium. As described above, in the light-emitting element of this embodiment mode, the first electrode 101 can be formed without depending on the work function of the substance. This is because the hole generating layer 111 is provided between the first electrode 101 and the light emitting layer 113.

  The second electrode 102 is preferably formed using a material having a low work function, for example, aluminum or magnesium, an alloy of silver and magnesium, or the like. In the case where an electron generating layer 115 is provided instead of the electron injecting layer 115. There are no restrictions on the work function. For example, indium tin oxide, indium tin oxide containing silicon oxide, indium oxide containing zinc oxide, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), You may form using substances with high work functions, such as molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and tantalum nitride.

  Further, a hole blocking layer 117 may be provided between the light emitting layer 113 and the electron transporting layer 114 as shown in FIG. By providing the hole blocking layer 117, holes can be prevented from penetrating through the light emitting layer 113 and flowing toward the second electrode 102, and the carrier recombination efficiency can be increased. In addition, the excitation energy generated in the light emitting layer 113 can be prevented from moving to another layer such as the electron transport layer 114. The hole blocking layer 117 is formed of a material that can be used to form the electron transport layer 114 such as BAlq, OXD-7, TAZ, or BPhen, and more particularly than a material that is used to form the light emitting layer 113. It can be formed by selecting a material with a high ionization potential. Similarly, a layer may be provided between the light emitting layer 113 and the hole transporting layer 112 to prevent electrons from passing through the light emitting layer 113 and flowing toward the first electrode 101. .

  Note that whether or not to provide the hole transport layer 112, the electron transport layer 114, and the electron injection layer 115 may be appropriately selected by the practitioner of the invention. For example, the hole transport layer 112, the electron transport layer 114, and the like are provided. If there is no problem such as quenching caused by metal even if not, these layers are not necessarily provided.

  The light emitting element of the present invention described above has little change in driving voltage depending on the thickness of the hole generating layer 111. Therefore, the distance between the light emitting layer 113 and the first electrode 101 can be easily adjusted by changing the thickness of the hole generating layer 111. In other words, the length of the optical path (optical path length) through which the emitted light passes is set so that the length of the emitted light can be efficiently extracted to the outside or the color purity of the emitted light extracted to the outside is improved. Easy to adjust. In addition, by increasing the thickness of the hole generation layer 111, unevenness on the surface of the first electrode 101 can be relaxed, and a short circuit between the electrodes can be easily prevented.

(Embodiment 2)
The light-emitting element of the present invention can reduce malfunction caused by crystallization of a compound contained in a layer provided in the light-emitting element. Moreover, the short circuit between electrodes can be prevented by increasing the thickness of the hole generating layer. Further, by changing the thickness of the hole generating layer, the optical path length can be adjusted, the efficiency of taking out emitted light can be increased, and light emission with good color purity can be obtained. Therefore, by using the light-emitting element of the present invention as a pixel, a favorable light-emitting device with few display defects due to malfunction of the light-emitting element can be obtained. In addition, by using the light-emitting element of the present invention as a pixel, a light-emitting device that can provide an image with favorable display color can be obtained. In addition, by using the light-emitting element of the present invention as a light source, a light-emitting device that can be favorably illuminated with few defects due to malfunction of the light-emitting element can be obtained.

  In this embodiment, a circuit configuration and a driving method of a light-emitting device having a display function will be described with reference to FIGS.

  FIG. 3 is a schematic view of a light emitting device to which the present invention is applied as viewed from above. In FIG. 3, a pixel portion 6511, a source signal line driver circuit 6512, a write gate signal line driver circuit 6513, and an erase gate signal line driver circuit 6514 are provided over a substrate 6500. The source signal line drive circuit 6512, the write gate signal line drive circuit 6513, and the erase gate signal line drive circuit 6514 are each an FPC (flexible printed circuit) 6503 which is an external input terminal via a wiring group. Connected. The source signal line driver circuit 6512, the writing gate signal line driver circuit 6513, and the erasing gate signal line driver circuit 6514 receive a video signal, a clock signal, a start signal, a reset signal, and the like from the FPC 6503, respectively. . A printed wiring board (PWB) 6504 is attached to the FPC 6503. Note that each driver circuit portion is not necessarily provided on the same substrate as the pixel portion 6511 as described above. For example, an IC chip mounted on an FPC on which a wiring pattern is formed (TCP) Etc., and may be provided outside the substrate.

  In the pixel portion 6511, a plurality of source signal lines extending in the column direction are arranged side by side in the row direction. In addition, current supply lines are arranged side by side in the row direction. In the pixel portion 6511, a plurality of gate signal lines extending in the row direction are arranged side by side in the column direction. In the pixel portion 6511, a plurality of sets of circuits including light-emitting elements are arranged.

  FIG. 4 is a diagram illustrating a circuit for operating one pixel. The circuit illustrated in FIG. 4 includes a first transistor 901, a second transistor 902, and a light emitting element 903.

  Each of the first transistor 901 and the second transistor 902 is a three-terminal element including a gate electrode, a drain region, and a source region, and has a channel region between the drain region and the source region. Here, since the source region and the drain region vary depending on the structure and operating conditions of the transistor, it is difficult to limit which is the source region or the drain region. Therefore, in this embodiment, regions functioning as a source or a drain are referred to as a first electrode of a transistor and a second electrode of the transistor, respectively.

  The gate signal line 911 and the writing gate signal line driving circuit 913 are provided so as to be electrically connected or disconnected by a switch 918. The gate signal line 911 and the erasing gate signal line driver circuit 914 are provided so as to be electrically connected or disconnected by a switch 919. The source signal line 912 is provided so as to be electrically connected to either the source signal line driver circuit 915 or the power source 916 by the switch 920. The gate of the first transistor 901 is electrically connected to the gate signal line 911. The first electrode of the first transistor is electrically connected to the source signal line 912, and the second electrode is electrically connected to the gate electrode of the second transistor 902. The first electrode of the second transistor 902 is electrically connected to the current supply line 917, and the second electrode is electrically connected to one electrode included in the light-emitting element 903. Note that the switch 918 may be included in the write gate signal line driver circuit 913. The switch 919 may also be included in the erase gate signal line driver circuit 914. Further, the switch 920 may also be included in the source signal line driver circuit 915.

  There is no particular limitation on the arrangement of transistors, light-emitting elements, and the like in the pixel portion. For example, they can be arranged as shown in the top view of FIG. In FIG. 5, the first electrode of the first transistor 1001 is connected to the source signal line 1004, and the second electrode is connected to the gate electrode of the second transistor 1002. The first electrode of the second transistor is connected to the current supply line 1005, and the second electrode is connected to the electrode 1006 of the light emitting element. Part of the gate signal line 1003 functions as a gate electrode of the first transistor 1001.

  Next, a driving method will be described. FIG. 6 is a diagram for explaining the operation of a frame over time. In FIG. 6, the horizontal direction represents the passage of time, and the vertical direction represents the number of scanning stages of the gate signal line.

  When image display is performed using the light emitting device of the present invention, the screen rewriting operation and the display operation are repeatedly performed during the display period. The number of rewrites is not particularly limited, but is preferably at least about 60 times per second so that a person viewing the image does not feel flicker. Here, a period during which one screen (one frame) is rewritten and displayed is referred to as one frame period.

As shown in FIG. 6, one frame is time-divided into four subframes 501, 502, 503, and 504 including a writing period 501a, 502a, 503a, and 504a and a holding period 501b, 502b, 503b, and 504b. . A light emitting element to which a signal for emitting light is given is in a light emitting state in the holding period. The ratio of the length of the holding period in each subframe is as follows: first subframe 501: second subframe 502: third subframe 503: fourth subframe 504 = 2 ³ : 2 ² : 2 ¹ : 2 ⁰ = 8: 4: 2: 1. As a result, 4-bit gradation can be expressed. However, the number of bits and the number of gradations are not limited to those described here. For example, eight subframes may be provided so that 8-bit gradation can be performed.

  An operation in one frame will be described. First, in the subframe 501, the write operation is performed in order from the first row to the last row. Therefore, the start time of the writing period differs depending on the row. From the row in which the writing period 501a ends, the storage period 501b is started in order. In the holding period, the light-emitting element to which a signal for emitting light is given is in a light-emitting state. Further, the processing proceeds to the next subframe 502 in order from the row in which the holding period 501b ends, and the writing operation is performed in order from the first row to the last row as in the case of the subframe 501. The operation as described above is repeated until the holding period 504b of the subframe 504 ends. When the operation in the subframe 504 is completed, the process proceeds to the next frame. Thus, the accumulated time of the light emission in each subframe is the light emission time of each light emitting element in one frame. Various display colors having different brightness and chromaticity can be formed by changing the light emission time for each light emitting element and combining them in various ways within one pixel.

  When it is desired to forcibly end the holding period in the row that has already finished writing and has shifted to the holding period before the writing up to the last row is completed as in the subframe 504, after the holding period 504b. It is preferable to provide an erasing period 504c and control to forcibly enter a non-light emitting state. Then, the row that is forcibly set to the non-light-emitting state is kept in the non-light-emitting state for a certain period (this period is referred to as a non-light-emitting period 504d). Then, as soon as the writing period 504a of the last row ends, the processing proceeds to the writing period of the next subframe (or frame) in order from the first row. Accordingly, it is possible to prevent the writing period 504a of the subframe 504 from overlapping with the writing period of the next subframe.

  In this embodiment, the subframes 501 to 504 are arranged in order from the longest holding period. However, the subframes 501 to 504 are not necessarily arranged as in the present embodiment, and may be arranged in order from the shortest holding period, for example. Alternatively, a long holding period and a short holding period may be arranged at random. In addition, the subframe may be further divided into a plurality of frames. That is, the gate signal line may be scanned a plurality of times during the period when the same video signal is applied.

  Here, the operation of the circuit shown in FIG. 4 in the writing period and the erasing period will be described.

  First, the operation in the writing period will be described. In the writing period, the gate signal line 911 in the n-th row (n is a natural number) is electrically connected to the writing gate signal line driving circuit 913 via the switch 918 and is connected to the erasing gate signal line driving circuit 914. Is disconnected. The source signal line 912 is electrically connected to the source signal line driver circuit 915 through the switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 in the n-th row (n is a natural number), and the first transistor 901 is turned on. At this time, video signals are simultaneously input to the source signal lines 912 from the first column to the last column. Note that the video signals input from the source signal lines 912 in each column are independent from each other. A video signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 through the first transistor 901 connected to each source signal line. At this time, a current value supplied from the current supply line 917 to the light-emitting element 903 is determined by a signal input to the second transistor 902. Then, depending on the current value, the light emitting element 903 determines light emission or non-light emission. For example, in the case where the second transistor 902 is a p-channel transistor, the light-emitting element 903 emits light by inputting a low level signal to the gate electrode of the second transistor 902. On the other hand, in the case where the second transistor 902 is an n-channel transistor, the light-emitting element 903 emits light when a high level signal is input to the gate electrode of the second transistor 902.

  Next, the operation in the erasing period will be described. In the erasing period, the gate signal line 911 in the n-th row (n is a natural number) is electrically connected to the erasing gate signal line driving circuit 914 via the switch 919, and is connected to the writing gate signal line driving circuit 913. Not connected. The source signal line 912 is electrically connected to the power source 916 through the switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 in the n-th row, and the first transistor 901 is turned on. At this time, the erase signal is simultaneously input to the source signal lines 912 from the first column to the last column. The erase signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 through the first transistor 901 connected to each source signal line. At this time, current supplied from the current supply line 917 to the light-emitting element 903 is blocked by a signal input to the second transistor 902. Then, the light emitting element 903 is forced to emit no light. For example, in the case where the second transistor 902 is a p-channel transistor, the light-emitting element 903 does not emit light when a high level signal is input to the gate electrode of the second transistor 902. On the other hand, in the case where the second transistor 902 is an n-channel transistor, the light emitting element 903 does not emit light by inputting a low level signal to the gate electrode of the second transistor 902.

  In the erasing period, for the nth row (n is a natural number), a signal for erasing is input by the operation as described above. However, as described above, the nth row may be an erasing period and the other row (mth row (m is a natural number)) may be a writing period. In such a case, it is necessary to input a signal for erasure to the n-th row and a signal for writing to the m-th row using the source signal line in the same column. It is preferable to operate as described above.

  The gate signal line 911 and the erasing gate signal line driving circuit 914 are immediately disconnected after the light emitting element 903 in the n-th row does not emit light by the operation in the erasing period described above. The switch 920 is switched to connect the source signal line 912 and the source signal line driver circuit 915. Then, the source signal line 912 and the source signal line driver circuit 915 are connected, and the gate signal line 911 and the writing gate signal line driver circuit 913 are connected. Then, a signal is selectively input from the writing gate signal line driver circuit 913 to the gate signal line 911 in the m-th row, the first transistor 901 is turned on, and the source signal line driver circuit 915 supplies one column. A signal for writing is input to the source signal line 912 from the first to the last column. By this signal, the light emitting element 903 in the m-th row emits light or does not emit light.

  Immediately after the writing period for the m-th row is completed as described above, the erasing period for the (n + 1) -th row is started. For this purpose, the gate signal line 911 and the writing gate signal line drive circuit 913 are disconnected, and the switch 920 is switched to connect the source signal line 912 to the power source 916. Further, the gate signal line 911 and the writing gate signal line driving circuit 913 are disconnected, and the gate signal line 911 is connected to the erasing gate signal line driving circuit 914. A signal is selectively input from the erasing gate signal line driver circuit 914 to the gate signal line 911 in the (n + 1) th row to turn on the signal to the first transistor 901, and an erasing signal is input from the power supply 916. In this way, immediately after the erasing period of the (n + 1) th row is completed, the writing period of the (m + 1) th row is started. Thereafter, similarly, the erasing period and the writing period may be repeated until the erasing period of the last row is operated.

  In this embodiment, the mode in which the m-th writing period is provided between the n-th erasing period and the (n + 1) -th erasing period has been described. An m-th writing period may be provided between the period and the n-th erasing period.

  In this embodiment, when the non-light emission period 504d is provided as in the subframe 504, the erasing gate signal line driver circuit 914 and one gate signal line are disconnected from each other, and the write gate The operation of connecting the signal line driver circuit 913 and the other gate signal line 911 to each other is repeated. Such an operation may be performed particularly in a frame in which a non-light emitting period is not provided.

(Embodiment 3)
One mode of a light-emitting device including the light-emitting element of the present invention is described with reference to a cross-sectional view of FIG.

  In FIG. 7, a transistor 11 provided for driving the light emitting element 12 of the present invention is surrounded by a dotted line. The light emitting element 12 is a light emitting element of the present invention having a layer 15 in which a hole generating layer, an electron generating layer, and a layer containing a light emitting substance are stacked between a first electrode 13 and a second electrode 14. . The drain of the transistor 11 and the first electrode 13 are electrically connected by a wiring 17 penetrating the first interlayer insulating film 16 (16a, 16b, 16c). The light emitting element 12 is separated from another light emitting element provided adjacent thereto by a partition wall layer 18. The light-emitting device of the present invention having such a structure is provided over the substrate 10 in this embodiment.

  Note that the transistor 11 illustrated in FIG. 7 is a top-gate transistor in which a gate electrode is provided on the side opposite to a substrate with a semiconductor layer as a center. However, the structure of the transistor 11 is not particularly limited, and may be, for example, a bottom gate type. In the case of a bottom gate, the semiconductor layer forming a channel may be formed with a protective film (channel protection type), or the semiconductor layer forming the channel may be partially concave ( Channel etch type).

  Further, the semiconductor layer included in the transistor 11 may be either crystalline or non-crystalline. Moreover, a semi-amorphous etc. may be sufficient.

The semi-amorphous semiconductor is as follows. A semiconductor having an intermediate structure between amorphous and crystalline (including single crystal and polycrystal) and having a third state that is stable in terms of free energy, has a short-range order, and has a lattice distortion. It contains a crystalline region. Further, at least a part of the region in the film contains crystal grains of 0.5 to 20 nm. The Raman spectrum is shifted to the lower wavenumber side than 520 cm ⁻¹ . In X-ray diffraction, diffraction peaks of (111) and (220) that are derived from the Si crystal lattice are observed. In order to terminate dangling bonds (dangling bonds), hydrogen or halogen is contained at least 1 atomic% or more. It is also called a so-called microcrystalline semiconductor (microcrystal semiconductor). Any one of SiH ₄ , Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , and SiF ₄ is formed by glow discharge decomposition (plasma CVD). These gases may be diluted with H ₂ , or H ₂ and one or more kinds of rare gas elements selected from He, Ar, Kr, and Ne. The dilution ratio is in the range of 2 to 1000 times, the pressure is in the range of approximately 0.1 Pa to 133 Pa, the power supply frequency is 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz, and the substrate heating temperature may be 300 ° C. or less, preferably 100 to 250 ° C. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ / cm ³ or less, and in particular, the oxygen concentration is 5 × 10 ¹⁹ / cm ³ or less, preferably 1 × 10 ¹⁹ / cm ³ or less. Note that the mobility of a TFT (thin film transistor) using a semi-amorphous semiconductor is approximately 1 to 10 m ² / Vsec.

  Further, specific examples of the crystalline semiconductor layer include those made of single crystal or polycrystalline silicon, silicon germanium, or the like. These may be formed by laser crystallization, or may be formed by crystallization by a solid phase growth method using nickel or the like, for example.

  Note that in the case where the semiconductor layer is formed of an amorphous material, for example, amorphous silicon, the transistor 11 and other transistors (transistors constituting a circuit for driving a light emitting element) are all configured by N-channel transistors. It is preferable that the light-emitting device have a structured circuit. Other than that, a light-emitting device having a circuit including any one of an N-channel transistor and a P-channel transistor, or a light-emitting device including a circuit including both transistors may be used.

  Further, the first interlayer insulating film 16 may be a multilayer as shown in FIGS. 7A and 7C, or may be a single layer. Note that 16a is made of an inorganic material such as silicon oxide or silicon nitride, and 16b is a skeleton structure composed of a bond of acrylic or siloxane (silicon (Si) and oxygen (O), and is an organic group such as hydrogen or an alkyl group. And a compound having self-flatness such as silicon oxide that can be coated and formed. Further, 16c is made of a silicon nitride film containing argon (Ar). In addition, there is no limitation in particular about the substance which comprises each layer, You may use things other than what was described here. Moreover, you may further combine the layer which consists of substances other than these. As described above, the first interlayer insulating film 16 may be formed using both an inorganic material and an organic material, or may be formed of any one of an inorganic material and an organic material.

  The partition layer 18 preferably has a shape in which the radius of curvature continuously changes at the edge portion. The partition layer 18 is formed using acrylic, siloxane, resist, silicon oxide, or the like. The partition wall layer 18 may be formed of any one of an inorganic material and an organic material, or may be formed using both.

  In FIGS. 7A and 7C, only the first interlayer insulating film 16 is provided between the transistor 11 and the light emitting element 12, but as shown in FIG. 7B, the first interlayer insulating film 16 is provided. In addition to the insulating film 16 (16a, 16b), the second interlayer insulating film 19 (19a, 19b) may be provided. In the light emitting device shown in FIG. 7B, the first electrode 13 penetrates through the second interlayer insulating film 19 and is connected to the wiring 17.

  Similar to the first interlayer insulating film 16, the second interlayer insulating film 19 may be a multilayer or a single layer. 19a is made of a self-flattening material such as acrylic, siloxane, or silicon oxide that can be coated and formed. Further, 19b is made of a silicon nitride film containing argon (Ar). In addition, there is no limitation in particular about the substance which comprises each layer, You may use things other than what was described here. Moreover, you may further combine the layer which consists of substances other than these. As described above, the second interlayer insulating film 19 may be formed using both an inorganic material and an organic material, or may be formed using any one of an inorganic material and an organic material.

  In the light-emitting element 12, when each of the first electrode 13 and the second electrode 14 is formed using a light-transmitting substance, the first electrode 13 and the second electrode 14 are formed as illustrated by the white arrows in FIG. Light emission can be extracted from both the first electrode 13 side and the second electrode 14 side. In addition, in the case where only the second electrode 14 is formed using a light-transmitting substance, light emission is extracted only from the second electrode 14 side as represented by a white arrow in FIG. 7B. be able to. In this case, it is preferable that the first electrode 13 is made of a material having a high reflectivity, or a film (reflective film) made of a material having a high reflectivity is provided below the first electrode 13. In addition, in the case where only the first electrode 13 is formed using a light-transmitting substance, light emission is extracted only from the first electrode 13 side as represented by a white arrow in FIG. be able to. In this case, it is preferable that the second electrode 14 is made of a highly reflective material, or a reflective film is provided above the second electrode 14.

  In addition, the light emitting element 12 may be one in which the layer 15 is stacked so as to operate when a voltage is applied so that the potential of the second electrode 14 is higher than the potential of the first electrode 13. Alternatively, the layer 15 may be stacked so as to operate when a voltage is applied so that the potential of the second electrode 14 is lower than the potential of the first electrode 13. In the former case, the transistor 11 is an N-channel transistor, and in the latter case, the transistor 11 is a P-channel transistor.

  As described above, in this embodiment mode, an active light-emitting device that controls driving of a light-emitting element using a transistor has been described. In addition to this, a light-emitting element is driven without particularly providing a driving element such as a transistor. A passive light emitting device may be used. FIG. 8 is a perspective view of a passive light emitting device manufactured by applying the present invention. In FIG. 8, a layer 955 in which a layer containing a light-emitting substance, an electron generation layer, and a hole generation layer are sequentially stacked is provided over a substrate 951 between an electrode 952 and an electrode 956. An end portion of the electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided over the insulating layer 953. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (the side facing the insulating layer 953 in the same direction as the surface direction of the insulating layer 953) is the top side (the surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, defects in the light-emitting element due to static electricity or the like can be prevented. A passive light emitting device can also be driven with low power consumption by including the light emitting element of the present invention that operates at a low driving voltage.

(Embodiment 4)
A light-emitting device using the light-emitting element of the present invention as a pixel has a good display operation with few display defects due to an operation failure of the light-emitting element. Therefore, by applying such a light-emitting device to a display portion, an electronic device with few display image misidentifications or the like due to display defects can be obtained. In addition, a light-emitting device using the light-emitting element of the present invention as a light source can be favorably illuminated with few defects due to malfunction of the light-emitting element. Therefore, by using such a light emitting device as an illuminating unit such as a backlight, by mounting the light emitting device of the present invention in this way, a dark part is locally formed due to a defect of the light emitting element. Such malfunctions can be reduced and a good display can be achieved.

  One embodiment of an electronic device mounted with a light emitting device to which the present invention is applied is shown in FIG.

  FIG. 9A illustrates a personal computer manufactured by applying the present invention, which includes a main body 5521, a housing 5522, a display portion 5523, a keyboard 5524, and the like. A personal computer can be completed by incorporating a light-emitting device using the light-emitting element of the present invention as a pixel as a display portion. Further, a personal computer can be completed even if a light emitting device using the light emitting element of the present invention as a light source is incorporated as a backlight. Specifically, as shown in FIG. 10, a liquid crystal device 5512 and a light-emitting device 5513 provided with at least one light-emitting element of the present invention are fitted in a display portion of a personal computer, as shown in FIG. Thus, a personal computer using the light emitting element of the present invention as a light source can be completed. An external input terminal 5515 is attached to the liquid crystal device 5512, and an external input terminal 5516 is attached to the light emitting device 5513. In the light-emitting device 5513, a plurality of light-emitting elements of the present invention may be arranged, or one light-emitting element may be provided so as to cover most of the substrate. In the light-emitting device 5513, the color of light emitted from the light-emitting element is not particularly limited, and may be white, red, blue, green, or the like.

  FIG. 9B illustrates a telephone manufactured by applying the present invention. The main body 5552 includes a display portion 5551, an audio output portion 5554, an audio input portion 5555, operation switches 5556 and 5557, an antenna 5553, and the like. ing. A telephone can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  FIG. 9C illustrates a television set manufactured by applying the present invention, which includes a display portion 5531, a housing 5532, a speaker 5533, and the like. A television receiver can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  As described above, the light-emitting device of the present invention is very suitable for use as a display portion of various electronic devices. Note that the electronic device is not limited to that described in this embodiment, and may be another electronic device such as a navigation device.

  Regarding the layers used in the practice of the present invention, the results of observation using a transmission electron microscope will be described.

A first layer 701 was formed on a silicon wafer by a co-evaporation method using molybdenum trioxide, DNTPD, and rubrene as raw materials on a silicon wafer 700, and a sample used for observation was manufactured (FIG. 11). . The thickness of the first layer 701 was set to 200 nm. Here, the co-evaporation method refers to an evaporation method in which raw materials are vaporized from a plurality of evaporation sources provided in one processing chamber, and are deposited on an object to be processed. The pressure in the processing chamber was adjusted to 1 × 10 ⁻⁴ Pa. Moreover, each raw material was heated and vaporized by the resistance heating method.

  Note that in the first layer 701 formed as described above, molybdenum trioxide, DNTPD, and rubrene each have a molar ratio of molybdenum atoms (= molybdenum atoms / DNTPD) to DNTPD of 3, and a molar ratio of rubrene to DNTPD ( = Rubrene / DNTPD) was adjusted to include 0.01.

  The cross section of the sample produced as described above was observed using a transmission electron microscope (TEM). During the observation, the first layer 701 was covered with a second layer 702 made of platinum. FIG. 12 shows an image (magnification: 1 million times) obtained by observation. From FIG. 12, it can be seen that in the first layer 701, the first regions 711 having dark colors and the second regions 712 having light colors alternately exist. That is, it was found that regions with high molybdenum concentration and regions with low molybdenum concentration exist alternately. Note that the first region 711 having a high molybdenum concentration has a distance of approximately 3 nm in the layer thickness direction, and the second region 712 having a low molybdenum concentration has a distance of approximately 3 nm in the layer thickness direction. It can be seen from FIG.

4A and 4B illustrate one embodiment of a light-emitting element of the present invention. 4A and 4B illustrate one embodiment of a light-emitting element of the present invention. FIG. 6 is a top view illustrating one embodiment of a light-emitting device of the present invention. 4A and 4B each illustrate one embodiment of a circuit for driving pixels provided in a light-emitting device of the present invention. 4A and 4B illustrate one embodiment of a pixel portion included in a light-emitting device of the present invention. 4 is a frame diagram illustrating a driving method for driving pixels included in the light-emitting device of the present invention. FIG. 3A and 3B each illustrate one embodiment of a cross section of a light-emitting device of the present invention. FIG. 6 is a perspective view illustrating one embodiment of a light-emitting device of the present invention. 6A and 6B illustrate one embodiment of an electronic device to which the present invention is applied. The figure explaining the illuminating device to which this invention is applied. 8A and 8B illustrate a manufacturing method of Example 1. FIG. An image obtained by observation using a transmission electron microscope.

Explanation of symbols

101 First electrode 102 Second electrode 111 Hole generation layer 112 Hole transport layer 113 Light emitting layer 114 Electron transport layer 115 Electron injection layer 117 Hole blocking layer 700 Silicon wafer 701 First layer 702 Second layer 6500 Substrate 6503 FPC (flexible printed circuit)
6504 Printed Wiring Board (PWB)
6511 Pixel portion 6512 Source signal line driving circuit 6513 Writing gate signal line driving circuit 6514 Erasing gate signal line driving circuit 901 First transistor 902 Second transistor 903 Light emitting element 911 Gate signal line 912 Source signal line 913 Writing Gate signal line driving circuit 914 erasing gate signal line driving circuit 915 source signal line driving circuit 916 power supply 917 current supply line 918 switch 919 switch 920 switch 951 substrate 952 electrode 953 insulating layer 954 partition wall layer 955 layer 956 electrode 1001 first Transistor 1002 Second transistor 1003 Gate signal line 1004 Source signal line 1005 Current supply line 1006 Electrode 501 Subframe 502 Subframe 503 Subframe 504 Subframe 501a Write period 501 b holding period 502a writing period 502b holding period 503a writing period 503b holding period 504a writing period 504b holding period 504c erasing period 504d non-light emitting period 10 substrate 11 transistor 12 light emitting element 13 first electrode 14 second electrode 15 layer 16 Interlayer insulating film 17 Wiring 18 Partition layer 19 Interlayer insulating film 5511 Case 5512 Liquid crystal device 5513 Light emitting device 5514 Case 5521 Body 5522 Case 5523 Display unit 5524 Keyboard 5551 Display unit 5552 Body 5553 Antenna 5554 Audio output unit 5555 Audio input unit 5556 Operation switch 5531 Display unit 5532 Housing 5533 Speaker

Claims (8)

A first electrode;
A second electrode provided opposite to the first electrode;
Provided between said first electrode and the second electrode, anda mixed layer containing a compound to a metal oxide and the metal oxide showing an electron donating property,
The mixed layer has a first region and a second region;
The first region and the second region are alternately provided from the first electrode toward the second electrode,
The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region;
The light emitting element, wherein the first region and the second region each have a thickness of 0.1 nm to 10 nm in a direction from the first electrode toward the second electrode. A first electrode;
A second electrode provided opposite to the first electrode;
Provided between said first electrode and the second electrode, anda mixed layer containing a compound to a metal oxide and the metal oxide showing an electron donating property,
The mixed layer has a first region and a second region;
The first region and the second region are alternately provided from the first electrode toward the second electrode,
The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region;
Each of the first region and the second region has a thickness of 0.1 nm or more and 10 nm or less in a direction from the first electrode toward the second electrode;
The light emitting element characterized by the molar ratio of the said metal oxide with respect to the said compound being 0.1-10 in the said mixed layer.   The light emitting device according to claim 1, wherein the compound is an aromatic amine compound. A first electrode;
A second electrode provided opposite to the first electrode;
Provided between the second electrode and the first electrode, metal oxides, a first compound showing an electron donating property to the metal oxide, and the first LUMO level than compound a mixed layer containing a low There second compound,
Have
The mixed layer has a first region and a second region,
The first region and the second region are alternately provided from the first electrode toward the second electrode,
The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region;
The light emitting element, wherein the first region and the second region each have a thickness of 0.1 nm to 10 nm in a direction from the first electrode toward the second electrode. A first electrode;
A second electrode provided opposite to the first electrode;
Provided between the second electrode and the first electrode, metal oxides, a first compound showing an electron donating property to the metal oxide, and the first LUMO level than compound a mixed layer containing a low There second compound,
Have
The mixed layer has a first region and a second region,
The first region and the second region are alternately provided from the first electrode toward the second electrode,
The concentration of the metal oxide contained in the first region is higher than the concentration of the metal oxide contained in the second region;
Each of the first region and the second region has a thickness of 0.1 nm or more and 10 nm or less in a direction from the first electrode toward the second electrode;
In the mixed layer, the molar ratio of the metal oxide to the first compound is 0.1 or more and 10 or less.   The light-emitting element according to claim 4, wherein the first compound is an aromatic amine compound.   The light emitting device according to claim 1, wherein the metal oxide includes a metal atom belonging to Group 4 to Group 8.   An electronic apparatus using the light-emitting element according to claim 1 as a pixel.