JP2010263039A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device using an organic EL element, wherein the lighting device obtains illumination light with a desired color tone by absorbing light of a component which is desirable in color tone and has a long wavelength among wavelength components of light emitted by the organic EL element as a light source and raising the color temperature, and also recycles energy of the absorbed light, and a method of manufacturing the same. <P>SOLUTION: The present invention relates to the lighting device 1 that emits the illumination light which has the desired color tone and is friendly to the eye by: converting part of light of first color temperature emitted by the organic EL element 22 serving as the light source into second color temperature higher than the first color temperature by an organic photoelectric conversion element 32; and generating recyclable electricity by the organic photoelectric conversion element 32, the lighting device 1 having superior energy efficiency and being excellently thin and lightweight. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lighting device using an organic EL element.

  Conventionally, there is an electroluminescence display as an electroluminescent display element. The electroluminescence display is composed of an inorganic electroluminescence element or an organic electroluminescence element (also referred to as an organic EL element).

  Inorganic electroluminescent elements are used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL device has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light emitting layer and recombining them. The light (fluorescence, phosphorescence) emitted when the exciton is deactivated is used. And since it has the following features, it attracts attention as a device for illumination.

  (1) Light emission is possible by applying a direct-current voltage of about several volts to several tens of volts between both electrodes.

  (2) Because of the self-luminous type, it has a wide viewing angle and high visibility.

  (3) Since it is a thin film type solid element, it saves space.

  (4) A surface light source, which is less dazzling and less likely to form shadows compared to conventional point light source illumination. Accordingly, it is expected to provide a light source that is gentle to the human eye by being incorporated in a wall surface (outer wall, inner wall) of a building or the like.

  In order to obtain a high-efficiency organic EL element, it is necessary to use a phosphorescent material having high luminous efficiency. However, due to the characteristics of the phosphorescent material, it is difficult to develop a blue phosphorescent material with a large band gap and high color purity. At present, only white illumination with a color temperature as low as about 3500K (strong redness) can be obtained. It has a problem.

  On the other hand, Patent Literature 1 and Patent Literature 2 disclose correction techniques for obtaining illumination light (for example, white light) having a desired spectrum by converting light emitted from the organic EL element itself.

  In the technique described in Patent Document 1, an organic EL element including a blue light emitting layer is formed on one side of a transparent substrate, and a green color forming layer having a green fluorescent dye and a red color forming layer having a red fluorescent dye are formed on the other surface of the transparent substrate. It is an illuminating device using organic EL elements that are sequentially formed and that drives the organic EL elements to emit white light from the other surface side of the transparent substrate. The blue light emitted from the organic EL element is converted into green light by the green fluorescent dye in the green color developing layer, and then further converted into red light by the red fluorescent dye in the red color developing layer, and blue light, green light and red light are converted. It emits white light in a balanced manner to the outside.

  The technique described in Patent Document 2 is a conversion for converting blue light into white light in an illumination cover of a lighting fixture using an organic light emitting diode (organic EL element) that emits blue light from a light emitting layer containing a blue light emitting polymer. Layers are to be placed. The conversion layer contains organic molecules such as perylene orange and perylene red, and inorganic phosphor particles.

Japanese Patent Laid-Open No. 9-204982 JP 2004-2001148 A

  The technique described in Patent Document 1 converts light such as ultraviolet light or blue light into light on the long wavelength side. As described above, the light-emitting organic EL element that emits light with high efficiency is blue light. Therefore, it cannot be used for the purpose of increasing the color temperature of light (increasing bluishness).

  The technique described in Patent Document 2 includes inorganic phosphor particles in a color conversion layer, and converts white light into long-wavelength light to generate white light. It is not effective in increasing the color temperature of light emitted from the organic EL element.

  In addition, it is conceivable that a color filter is interposed to selectively absorb light in a long wavelength region that is not preferable in terms of color tone to increase the color temperature to obtain illumination light of a desired color tone. Is a problem in terms of energy efficiency because it is lost without being used as energy.

  The object of the present invention is to absorb the light of a long wavelength component from the viewpoint of the color tone among the wavelength components of the light emitted from the organic EL element as a light source, and increase the color temperature to obtain illumination light of a desired color tone. An object of the present invention is to provide an illuminating device using an organic EL element and a method for manufacturing the same, which makes it possible to reuse energy of absorbed light.

  The above problems have been solved by the configuration described below.

1. An organic electroluminescent element that emits light of a first color temperature as a light source for illumination by supplying power;
An organic photoelectric conversion element that generates electricity by absorbing a part of the light emitted by the organic electroluminescence element;
A lighting device comprising:
An illumination device, wherein a color temperature of illumination light emitted to the outside by light absorption of the organic photoelectric conversion element is changed to a second color temperature higher than the first color temperature.

  2. 2. The illumination device according to 1, wherein a difference between the second color temperature and the first color temperature is 200K or more.

  3. The average color rendering index of luminescence emitted from the organic electroluminescence device converts the average color rendering index of illumination light emitted to the outside by light absorption of the organic photoelectric conversion device into a higher value. Or the illuminating device of 2.

  4). 4. The lighting device according to claim 1, further comprising a supply circuit that supplies electric power generated by the organic photoelectric conversion element to the organic electroluminescence element.

  5. 5. The lighting device according to claim 1, further comprising a power storage unit that stores electric power generated by the organic photoelectric conversion element.

  6). 6. The lighting device according to any one of 1 to 5, wherein the organic electroluminescent element has a light emitting layer containing a phosphorescent material.

  7). The lighting device according to any one of 1 to 6, wherein the organic photoelectric conversion element has a bulk heterojunction layer having a fullerene derivative.

  8). 8. The illumination device according to any one of 1 to 7, wherein an absorption spectrum of the organic photoelectric conversion element satisfies the following formula 1.

Formula 1 A600 / A450> 1
A450 is an absorption value at a wavelength of 450 nm, and A600 is an absorption value at a wavelength of 600 nm.

  9. 9. The illumination device according to any one of 1 to 8, wherein the maximum of the absorption spectrum of the organic photoelectric conversion element is 700 nm or more.

  10. 10. The lighting device according to any one of 1 to 9, wherein the organic electroluminescent element or the organic photoelectric conversion element is in a form covered with a gas barrier film.

  11. 11. The lighting device according to any one of 1 to 10, wherein the organic electroluminescent element and the organic photoelectric conversion element are integrally laminated.

12 A reflective layer that reflects light emitted from the organic electroluminescent device to the outside;
The lighting device according to any one of 1 to 10, wherein the reflective layer, the organic electroluminescent element, and the organic photoelectric conversion element are arranged in this order.

  13. The organic electroluminescence device and the organic photoelectric conversion device use a common transparent base material, the organic electroluminescence device is disposed on one side of the base material, and the organic photoelectric conversion device is disposed on the other side of the base material. 13. The lighting device according to 12, wherein the lighting device is disposed.

  14 The organic electroluminescence device and the organic photoelectric conversion device are formed by a solution process in which a coating liquid, which is a liquid composition, is applied to a substrate by a coating means to form a coating film layer. 14. The lighting device according to any one of items 13 to 13.

  The present invention converts a part of the light of the first color temperature emitted from the organic electroluminescent element (organic EL element) of the light source into a second color temperature higher than the first color temperature by the organic photoelectric conversion element, and can be reused. By generating electric power with an organic photoelectric conversion element, it is possible to emit illumination light that is gentle on the eyes of a desired color tone, and to provide an illumination device that is excellent in energy efficiency, thinness, and lightness. Further, not only the color temperature but also the average color rendering index representing how the original color of an object looks when illuminated by illumination can be improved.

  As a further effect, since the light emitting element and the photoelectric conversion element are integrated, not only simply generating electricity with sunlight during the day and causing the light emitting element to emit light at night, but also when the light emitting element emits light. It is possible to provide a lighting device with high energy efficiency that can absorb light in the above preferable wavelength range and can be reused as energy.

Sectional drawing which shows embodiment of the illuminating device which concerns on this invention. Sectional drawing which shows other embodiment in the illuminating device which concerns on this invention. The top view and sectional surface which show the electrode structure of an organic photoelectric conversion element. The equivalent circuit schematic of the illuminating device which concerns on this invention. The equivalent circuit of the other illuminating device which concerns on this invention. The light absorption spectrum of the organic photoelectric conversion element which concerns on this invention, and the emission spectrum of an organic EL element. The optical spectrum of the illumination light irradiated from the Example and comparative example which concern on this invention.

  Hereinafter, although embodiment of this invention is described, this invention is not limited to this.

  Fig.1 (a) is sectional drawing and front view which show an example of the illuminating device based on this invention.

  As illustrated, an illuminating device 1 includes an organic EL member 2 composed of an organic electroluminescent element as a light source of the illuminating device, and an organic photoelectric conversion capable of generating electricity by absorbing part of the light from the organic EL member 2 It has the member 3, the reflective member 4 which irradiates the emitted light from the organic EL member 2 efficiently to a desired illumination area, and the support member 5.

  The organic EL member 2 includes a transparent and flexible film substrate 21 as a substrate, and an organic EL element (Organic light-emitting diode, OLED) as an organic electroluminescent device formed on the surface of the film substrate 21. 22), and has a feature of a light source that does not form glare and shadow as so-called planar light emission.

  Although the aspect (configuration) of the organic EL element 22 will be described in detail later, it is an organic EL element made of a phosphorescent material having high luminous efficiency. The color temperature of the emitted light is 3620K, and it has an emission spectrum as shown by the solid line B in FIG.

  The reflective member 4 has a transparent and flexible film 41 as a base material and a reflective layer 42 made of aluminum or the like formed on the surface of the flexible film 41, and radiates light from the organic EL member 2 on the illumination side. It is a reflection. A flexible and low water vapor permeable aluminum foil may be used as the film 41, and an insulating layer may be provided so as not to cause current leakage or the like in the internal organic EL element.

  The organic photoelectric conversion member 3 is in the form of a film and is supported by the support portion 5 so as to be located on the opposite side of the reflecting member 4 with respect to the organic EL member 2 and to face the surface of the organic EL member 2. Most of the light emitted from the organic EL element 22 passes through the organic photoelectric conversion member 3 and is emitted to the illumination side G.

  The organic photoelectric conversion member 3 includes a transparent and flexible film base 31 as a base and an organic photoelectric conversion element 32 formed on the surface of the film base 31, and emitted light from the organic EL element 22. Is a solar cell (also referred to as “Organic Photovoltaics”, also referred to as OPV). The configuration of the organic photoelectric conversion element 32 will be described in detail later.

  The organic photoelectric conversion element 32 absorbs a part of the radiated light (indicated by a solid line arrow) emitted from the phosphorescent organic EL element 22 and converts it into desired white illumination light (indicated by a broken line arrow). Furthermore, electricity is generated by the energy of the absorbed light. In other words, a part of the radiated light emitted from the organic EL element 22 (that is, light in an unfavorable wavelength range) is absorbed to generate electricity that can be reused by the organic EL element 22.

  FIG. 6 is an example of a light absorption spectrum of the organic photoelectric conversion element 32 and an emission spectrum of the organic EL element 22. The vertical axis represents the absorbance (relative value) of the organic photoelectric conversion element 32 and the emission intensity (relative value) of the organic EL element 22, and the horizontal axis represents the wavelength (nm).

  A broken line curve B in FIG. 6 shows an emission spectrum emitted from the organic EL element 22. It has a maximum value of emission intensity in the vicinity of 620 nm. When the organic EL element 22 is used in a lighting device, the light intensity in a wavelength region of 600 nm or more exhibits reddish irradiation light, which reduces the color rendering properties (color temperature, average color rendering index) as illumination light. Yes.

  A solid curve A in FIG. 6 shows a light absorption spectrum of a typical organic photoelectric conversion element 32 according to the present invention. As shown in the figure, it has high absorption characteristics in the wavelength range of 600 nm to 800 nm, and the maximum value of light absorption is 700 nm or more. That is, an illumination device that emits illumination light with excellent color rendering properties is realized by allowing the emitted light from the organic EL element 22 to pass through the organic photoelectric conversion element 32. Furthermore, a lot of absorbed light having a wavelength of 600 nm or more is converted into reusable electricity, which makes it possible to realize an illumination device that is excellent in terms of energy utilization.

  In the form shown in FIG. 1A, all of the light emitted from the organic EL element 22 of the organic EL member 2 passes through the organic photoelectric conversion element 32 of the organic photoelectric conversion member 3 and is emitted to the illumination side. is there.

  FIG. 1B shows a form in which the arrangement relationship between the organic EL member 2 and the organic photoelectric conversion member 3 is exchanged. Of the light emitted and emitted from the organic EL element 22, only the light emitted to the back surface side can be absorbed. Therefore, the color conversion efficiency for converting to a desired color temperature and the power generation efficiency are inferior. In some cases, the organic EL device is advantageous in terms of light emission efficiency.

  FIG. 2 is a cross-sectional view and a front view showing an example of a lighting device according to another embodiment of the present invention.

  In this embodiment, the transparent organic EL member 2 and the flexible film base materials 21 and 31 of the organic photoelectric conversion member 3 are used in common, and this point is greatly different from the embodiment shown in FIG. The organic EL element 22 is formed on one surface of the film substrate 21, and the organic photoelectric conversion element 32 is formed on the other surface of the film substrate 21. Or the form which overlaps the film surface side of the film base material 21 of the organic EL element 22 and the film base material 31 of the organic photoelectric conversion element 32 which were formed separately may be sufficient.

  As shown in the figure, the organic EL element 22 includes an organic EL layer 221 having a layer configuration described in detail later, an anode 222 as an electrode for applying an electric field thereto, and a cathode 223.

  Similarly, the organic photoelectric conversion element 32 includes an organic photoelectric conversion layer 321, an anode 322 as an electrode for flowing electricity generated by the organic photoelectric conversion layer 321, and a cathode 323. The cathode 223 of the organic EL element 22 has a configuration that also serves as a reflecting member that reflects light. The other three electrodes, that is, the anode 222, the cathode 323, and the anode 322 are transparent electrodes. Therefore, in the form of FIG. 2, the reflecting member 4 of FIG. 1 is abolished.

  In addition, the transparent gas barrier film 61 shown in the figure protects the organic EL element 22 and the organic photoelectric conversion element 32.

  The lighting device according to the present invention shown in FIG. 2 is more preferable in terms of light weight, thinness and cost.

[Supply circuit of power generated by organic photoelectric conversion element 32]
FIG. 3 shows a case where a large number of sub organic photoelectric conversion elements 32j are formed on the film base 21 and the sub organic photoelectric conversion elements 32j are connected in series to increase the voltage to enable the organic EL element 22 to emit light. A circuit configuration for supplying electric power to the EL element 22 is shown.

  3A is a front view of the illumination device 1 as viewed from the illumination side, and FIG. 3B is a cross-sectional view taken along line AA ′ of FIG.

  The organic photoelectric conversion element 32 is divided into N sub organic photoelectric conversion elements 32j. The sub photoelectric conversion element 32j includes a sub anode 322j, a sub cathode 323j facing the sub anode 323j, and a sub organic photoelectric conversion layer 321j sandwiched between both electrodes. As shown in the drawing, the sub organic photoelectric conversion elements 32 are arranged in the order of 321, 322,... 32 (N-1), 32N from the left.

  As shown in FIG. 3 (b), the organic EL element 22 is formed on the lower surface side of the film substrate 21, and the sub organic photoelectric conversion element 32j (j = 1, 2,...) Divided into N on the upper surface side. An organic photoelectric conversion element 32 made of N-1, N) is formed. The first sub-organic photoelectric conversion element 321 includes a first sub-cathode 3231 formed on the upper surface of the film substrate 21, a sub-organic photoelectric conversion layer 3211 formed by coating on the sub-cathode 3231, The layer is constituted by a transparent anode 3221 formed on the upper surface of the photoelectric conversion layer 3211. Each sub organic photoelectric conversion element 321j is divided into a plurality of parts by separating both electrodes (anode and cathode) from each other.

  Note that the sub-anode 322 (j-1) and the sub-cathode 323j are electrically connected at an end (not shown), and the sub-photoelectric conversion elements 32j are connected in series.

  By this series connection, a voltage equal to or higher than the driving voltage that enables the organic EL element 22 to emit light is formed between the terminals of the cathode 3231 of the first sub photoelectric conversion element 321 and the anode 322N of the Nth photoelectric conversion element 32N. .

  The illumination device according to the present invention of this embodiment makes it possible to reuse the power generated by the organic photoelectric conversion element 32 for driving the organic EL element 22 without using a special booster circuit, and is lightweight. -It is a form that is superior in terms of thinness and cost.

  FIG. 4A is an equivalent circuit diagram of a lighting device according to the present invention using the organic photoelectric conversion element shown in FIG.

  The lighting device 1 includes a connector 7, an organic photoelectric member 3 including an organic photoelectric conversion element 32, and an organic EL member 2 including an organic EL element 22. The power supply unit ES is outside the lighting device 1, and the output terminal of the power supply unit ES is connected to the connector 7 with a lead wire.

  The organic photoelectric conversion element 32 includes N sub organic photoelectric conversion elements 32j (j = 1, 2,..., N−1, N) connected in series as illustrated.

  Here, the supply circuit C includes an organic photoelectric conversion element 32 in which N sub organic photoelectric conversion elements are connected in series, a lead C1 that conducts the cathode of the sub organic photoelectric conversion element 321 and the cathode of the organic EL element, and a sub organic It is comprised by the lead wire C2 which conduct | electrically_connects the anode of the photoelectric conversion element 321, and the anode of an organic EL element.

  When the light emission of the organic EL element 22 is driven by the supply circuit C in FIG. 4, a voltage exceeding the drive voltage Ea of the organic EL element 22 is generated in the organic photoelectric conversion element 32. As indicated by the arrow b, a current amount Iph corresponding to the amount of radiation absorbed is supplied to the organic EL element 22.

  Each sub organic photoelectric conversion element 32j can be approximately shown by an equivalent circuit as shown in FIG. Iph is a current source that increases in accordance with the amount of light emitted and absorbed from the organic EL element 22, and D1 is a diode. R1 is a parallel resistance component, which is caused by a leakage current or the like, and the higher this, the better the performance. R2 is a series resistance component.

  FIG. 5 shows a supply circuit C according to another embodiment of the present invention. In this embodiment, the power storage means 8 (capacitor or secondary battery) is arranged in parallel with the organic photoelectric conversion element 32 of the lighting device 1. The supply circuit C in this form includes a storage unit 8 that stores electricity generated by the organic photoelectric conversion element 32, and a boosting unit that boosts the electricity stored in the storage unit 8 to a drive voltage at which the organic EL element 22 can emit light. 9.

  The step-up means 9 outputs a voltage exceeding the drive voltage Ea of the organic EL element 22 using the current from the power storage means 8 as indicated by the broken line arrow C, and is a DC-DC converter. The boosting means 9 is operated appropriately or constantly so that the electricity stored in the power storage means 8 can be used for the light emission of the organic EL element 22 of the lighting device 1.

  That is, when the light emission of the organic EL element 22 is driven, the generated current Iph of the organic photoelectric conversion element 32 flows into the power storage unit 8 as indicated by the arrow b. When the booster 9 is activated. The electricity stored in the power storage means 8 is supplied to the organic EL element 22 side through the voltage boosting means 9 as indicated by a broken line arrow d. Here, the booster 9 is disposed outside the lighting device 1, but may be provided inside the lighting device 1.

  In the form of FIG. 5, the supply circuit C includes at least a power storage unit 8 connected in parallel to the organic photoelectric conversion member 3, a boosting unit 9, and a lead wire.

  The lighting device 1 in the form shown in FIG. 5 can also drive the lighting device 1 continuously for a predetermined period by using the electricity stored in the power storage means 8 even when the power supply drops due to a power failure or the like. It is to make.

[Mode of Organic EL Element 22]
Although the preferable aspect of the organic EL element 22 which concerns on this invention is demonstrated below, it is not limited to this.

  The organic EL element 22 is not particularly limited as long as it has at least one organic layer sandwiched between an anode and a cathode, and emits light when a current is passed.

  This is a preferred specific example of the layer structure of the organic EL element 22 formed on the surface of the film substrate 21, and is shown below.

(1) Anode / light emitting layer / electron transport layer / cathode (2) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (3) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (4) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (5) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (6) Anode / hole transport layer / first light emitting layer / electron transport layer / intermediate electrode / hole transport layer / second light emitting layer / electron transport layer / cathode The light emitting layer preferably contains at least two kinds of light emitting materials having different emission colors, and may form a light emitting layer unit composed of a single layer or a plurality of light emitting layers. Alternatively, a tandem configuration (configuration (6)) in which a plurality of light emitting stacks are stacked may be used. The hole transport layer also includes a hole injection layer and an electron blocking layer.

  Each of the above layers can be formed by a known method, for example, a vacuum deposition method, a spin coating method, a casting method, or the like. A coating solution that is a liquid composition is applied to a substrate by a coating means such as a coater or an inkjet. A coating method for forming a layer of a coating film, a so-called solution process method (described in JP-A-2004-75951) is preferable for improving productivity.

<Light emitting layer>
The light-emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light-emitting portion is the light-emitting layer even in the light-emitting layer. It may be an interface with an adjacent layer. The light emitting layer is not particularly limited in its configuration as long as the light emitting material included satisfies the above requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength.

  It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

  The total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably 30 nm or less because a lower driving voltage can be obtained. Note that the sum of the thicknesses of the light-emitting layers shown here is a thickness including the intermediate layer when a non-light-emitting intermediate layer exists between the light-emitting layers.

  The thickness of each light emitting layer is preferably adjusted to a range of 1 to 50 nm, more preferably adjusted to a range of 1 to 20 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.

  For the production of the light emitting layer, a light emitting material or a host compound, which will be described later, is formed by forming a film by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, or the like. it can.

  A plurality of light emitting materials may be mixed in each light emitting layer, or a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.

  As a structure of the light emitting layer, it is preferable to contain a host compound and a light emitting material (also referred to as a light emitting dopant compound) and emit light from the light emitting material.

  As a host compound contained in the light emitting layer of the organic EL element 22, a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1 at room temperature (25 ° C.) is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of luminescent material mentioned later, and can thereby obtain arbitrary luminescent colors.

  The host compound may be a conventionally known low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host).

  As the known host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable. Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Next, the light emitting material will be described.

  As the light-emitting material, a phosphorescent material (also referred to as a phosphorescent compound or a phosphorescent compound) is used.

  The phosphorescent material is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.) and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., but a preferable phosphorescence quantum yield is 0.1 or more. It is.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in a solution can be measured using various solvents. However, when a phosphorescent material is used in the present invention, the above phosphorescence quantum yield (0.01 or more) is obtained in any solvent. It only has to be achieved.

  The phosphorescent light-emitting material can be appropriately selected from known materials used for the light-emitting layer of the organic EL element, but is preferably a complex compound containing a group 8-10 metal in the periodic table of elements. More preferred are iridium compounds, osmium compounds, platinum compounds (platinum complex compounds), and rare earth complexes. Of these, iridium compounds are the most preferred.

  Specific examples of the iridium compound include Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, 4, 695-709 (2004), and the like.

  In the present invention, at least one light emitting layer may contain two or more kinds of light emitting materials, and the concentration ratio of the light emitting materials in the light emitting layer may vary in the thickness direction of the light emitting layer.

<Intermediate layer>
A case where a non-light emitting intermediate layer (also referred to as an undoped region or the like) is provided between the light emitting layers will be described.

  The non-light emitting intermediate layer is a layer provided between the light emitting layers in the case of having a plurality of light emitting layers.

  The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 20 nm, and further in the range of 3 to 10 nm suppresses interaction such as energy transfer between adjacent light emitting layers, and the current of the device This is preferable because a large load is not applied to the voltage characteristics.

  The material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but may be the same as the host material of at least one of the adjacent light emitting layers. preferable.

  Since the host material is responsible for carrier transportation, a material having carrier transportation ability is preferable. Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance between injection and transport of holes and electrons, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.

  On the other hand, in order to optimally adjust the injection balance of holes and electrons, it is also preferable that the non-light emitting intermediate layer functions as a blocking layer described later, that is, a hole blocking layer and an electron blocking layer. It is done.

<Injection layer: electron injection layer, hole injection layer>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to lower drive voltage and improve light emission luminance. “Organic electroluminescence device and its forefront of industrialization (November 30, 1998, NTS Corporation) Issue) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123 to 166), which is described in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, described in JP-A Nos. 11-204258 and 11-204359, and “Organic electroluminescence device and its industrialization front line (issued by NTT Corporation on November 30, 1998)”. There is a hole blocking layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

<Hole transport layer>
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si, p-type-SiC, nickel oxide, and molybdenum oxide can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

<Electron transport layer>
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as well as the hole injection layer and the hole transport layer. It can be used as an electron transport material.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be produced.

  In addition, n-type conductive inorganic oxides (titanium oxide, zinc oxide, etc.) can also be used.

<electrode>
The surface light emitting device according to the present invention has at least a first electrode and a second electrode. When an organic EL element is used, one is usually composed of an anode and the other is a cathode. Further, when a tandem configuration is adopted, the tandem configuration can be achieved by using an intermediate electrode. The preferred anode and cathode configurations are described below.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode substances include metal thin films such as gold, silver, and platinum, or conductive / light-transmitting materials such as nanoparticle / nanowire layers, indium tin oxide (ITO), SnO ₂ , and ZnO, and Examples include conductive polymers. Alternatively, a material such as IDIXO (In ₂ O ₃ —ZnO) that can form an amorphous light-transmitting conductive film may be used. The sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃₎ mixture, indium, a lithium / aluminum mixture, and rare earth metals.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  In addition, in order to transmit the emitted light, either the anode or the cathode of the organic EL element can be configured by appropriately using the electrode material so as to be light transmissive.

When making the anode side light-reflective, for example, aluminum and aluminum alloy, silver and silver compounds can be used to make light-reflective, and the light-reflective layer using these materials, the ITO, A light-transmitting anode such as SnO ₂ or ZnO can also be used in combination.

  When the cathode side is made light-transmitting, for example, a conductive material such as aluminum and an aluminum alloy, silver and a silver compound is made thin with a thickness of about 1 to 20 nm, and then mentioned in the description of the anode. By providing a film of a conductive light-transmitting material, a light-transmitting cathode can be obtained.

<Intermediate electrode>
The intermediate electrode material required for the tandem structure as described in (6) is preferably a layer using a compound having both transparency and conductivity, such as ITO, AZO, FTO, and titanium oxide. Preferred are transparent metal oxides such as Ag, Al, Au, etc., very thin metal layers or layers containing nanoparticles / nanowires, conductive polymer materials such as PEDOT: PSS, polyaniline, and the like.

  In addition, in the hole transport layer and the electron transport layer described above, there is also a combination that works as an intermediate electrode (charge recombination layer) by appropriately combining and laminating, and with such a configuration, the process of forming one layer This is preferable because it can be omitted.

<Sealing member>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive.

  The sealing member may be disposed so as to cover the light emitting region of the organic EL element, and may be a concave plate shape or a flat plate shape. Moreover, transparency and electrical insulation are not particularly limited.

  In the form of FIG. 2, the organic EL element 22, the organic photoelectric conversion element 32, and the base material 21 are integrally sealed with film-like sealing members 51 and 52.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Further, the polymer film preferably has an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻³ g / m ² / day or less. Moreover, it is more preferable that both the water vapor permeability and the oxygen permeability are 10 ⁻⁵ g / m ² / day or less.

  In addition, a method of spin-coating an organic polymer material (polyvinyl alcohol, etc.) having a high gas barrier property, a method of depositing an inorganic thin film (silicon oxide, aluminum oxide, etc.) or an organic film (parylene, etc.) having a high gas barrier property under vacuum, Also, a method of laminating these in a composite manner or the like can be used.

<Protective film, protective plate>
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

<Light extraction>
An organic EL element generally emits light within a layer having a refractive index higher than that of air (refractive index of about 1.6 to 2.1) and can extract only about 15 to 20% of light generated in the light emitting layer. It is said to be. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be extracted outside the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  In the present invention, these methods can be used in combination with the element according to the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate and a transparent electrode A method of forming a diffraction grating between any of the layers and the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less.

  The surface light emitting device according to the present invention is processed to provide a structure on the microlens array on the light extraction side of the support substrate, or is combined with a so-called condensing sheet, for example, in a specific direction, for example, device light emission. Condensing light in the front direction with respect to the surface can increase the luminance in a specific direction.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Co., Ltd. can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

  The illuminating device according to the present invention has a wide viewing angle, high visibility, and light and thin illumination by using the organic EL element 22 in the form as shown in FIG. Making it achievable.

[Mode of Organic Photoelectric Conversion Element 32]
As shown in FIG.1 and FIG.2, the organic photoelectric conversion element 32 (solar cell) of the organic photoelectric conversion member 3 used for the illuminating device which concerns on this invention is the wavelength component (the solar cell) which has deteriorated the color temperature as illumination light ( It is preferable to have a light absorption characteristic that relatively strongly absorbs the red component) and that can efficiently generate electricity by the light absorption. In particular, when white illumination light is obtained using a phosphorescent organic EL element, an organic photoelectric conversion element having a maximum in the red region in light absorption characteristics is suitable.

  There are at least one power generation layer (a layer in which a p-type semiconductor and an n-type semiconductor are mixed, a bulk heterojunction layer, or an i layer) sandwiched between the anode and the cathode, and generates an electric current when irradiated with light. Anything is acceptable.

  The preferable specific example of the layer structure of the organic photoelectric conversion element 32 is shown below.

(1) Anode / power generation layer / cathode (2) Anode / hole transport layer / power generation layer / cathode (3) Anode / hole transport layer / power generation layer / electron transport layer / cathode (4) Anode / hole transport layer / P-type semiconductor layer / power generation layer / n-type semiconductor layer / electron transport layer / cathode (5) Anode / hole transport layer / first light-emitting layer / electron transport layer / intermediate electrode / hole transport layer / second light-emitting layer / Electron transport layer / cathode The above power generation layer preferably has a light absorption characteristic that relatively strongly absorbs the wavelength component (red component) that deteriorates the color temperature as illumination light. The power generation layer needs to contain a p-type semiconductor material that can transport holes and an n-type semiconductor material that can transport electrons.

  These may have a structure in which a heterojunction is formed substantially in two layers, but a structure in which a bulk heterojunction formed in a mixed state in one layer is excellent in photoelectric conversion efficiency and is preferable. Furthermore, since the efficiency of taking out holes and electrons to the anode / cathode can be increased by sandwiching the power generation layer between the hole transport layer and the electron transport layer, the layers (2) and (3) having them. The configuration is more preferable than the layer configuration of (1). Further, when the power generation layer is sandwiched between layers composed of a p-type semiconductor material and a single n-type semiconductor material as in (4) (also referred to as a pin structure), the power generation layer itself has holes and holes. Electron rectification (selection of carrier extraction) can be improved, and this is more preferable. Moreover, in order to improve the utilization efficiency of sunlight, the tandem configuration ((5) layer configuration) in which sunlight of different wavelengths is absorbed by each power generation layer may be employed.

  Layers other than the power generation layer described below can be formed using the same material as that of the organic EL element as long as it conforms to the HOMO / LUMO level of the material used for the power generation layer.

<P-type semiconductor material>
Examples of the p-type semiconductor material used for the power generation layer (bulk heterojunction layer) of the present invention include various condensed polycyclic aromatic low-molecular compounds and conjugated polymers, and among these, the emission wavelength characteristics of the organic EL element and A material having a light absorption characteristic determined by a desired color temperature as illumination is selected.

  For example, in order to provide a lighting device as a white light source using a phosphorescent organic EL element, the following materials having a maximum value in light absorption characteristics in the red region can be cited.

  Examples of the condensed polycyclic aromatic low-molecular compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthracene, bisanthene, zeslen, Compounds such as heptazeslen, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF ) -Perchloric acid complexes, and derivatives and precursors thereof.

  Examples of the derivative having the above-mentioned condensed polycycle include WO 03/16599 pamphlet, WO 03/28125 pamphlet, US Pat. No. 6,690,029, JP 2004-107216 A. A pentacene derivative having a substituent described in JP-A No. 2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol127. No. 14.4986, J. MoI. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. 9, acene-based compounds substituted with a trialkylsilylethynyl group described in 2706 and the like.

  Examples of the conjugated polymer include a polythiophene such as poly-3-hexylthiophene (P3HT) and an oligomer thereof, or a technical group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Polythiophene, Nature Material, (2006) vol. 5, p328, polythiophene-thienothiophene copolymer, WO 2008/000664, polythiophene-diketopyrrolopyrrole copolymer, Adv Mater, 2007 p4160, polythiophene-thiazolothiazole copolymer, Nature Mat. vol. 6 (2007), p497 described in PCPDTBT, etc., polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, Examples thereof include polymer materials such as σ-conjugated polymers such as polysilane and polygermane.

  In addition, oligomer materials, not polymer materials, include thiophene hexamer α-seccithiophene α, ω-dihexyl-α-sexualthiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3 Oligomers such as -butoxypropyl) -α-sexithiophene can be preferably used.

  Among these compounds, the solubility in an organic solvent is as high as possible in the solution process described in JP-A-2004-75951, and a crystalline thin film is formed after drying to achieve high mobility. Preferred is a compound capable of

  In addition, as a p-type semiconductor material for increasing the color temperature of the phosphorescent organic EL device, which is an object of the present invention, a compound having an absorption maximum in the orange to red region of the phosphorescent organic EL device. It is preferable that

  Examples of such a compound include pentacene derivatives having substituents described in JP-A No. 2004-107216, pentacene precursors described in US Patent Application Publication No. 2003/136964, and the like. Amer. Chem. Soc. , Vol127. No. 14.4986, J.H. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. An acene-based compound substituted with a trialkylsilylethynyl group described in US Pat. No. 9,2706, a polythiophene-diketopyrrolopyrrole copolymer described in WO2008 / 000664, Nature Mat. vol. 6 (2007), p497, PCPDTBT, Adv. Mater. Examples thereof include polythiophene copolymers such as PCDTBT described in 2007, 19, 2295, and materials such as porphyrins and phthalocyanine compounds. Among the above materials, as a material that can be applied, a soluble substituent reacts and insolubilizes by applying energy such as heat as described in Japanese Patent Application Laid-Open No. 2008-16834 which is a porphyrin compound (pigmentation). Material).

  Among the above materials, as shown by a solid line B in FIG. 6, a compound having an absorption spectrum satisfying the following formula 1 is preferable.

A600 / A450> 1 Formula 1
A450 is an absorption value at a wavelength of 450 nm, and A600 is an absorption value at a wavelength of 600 nm. 450 nm is a region having a blue spectrum emitted from the phosphorescent organic EL device, and the smaller the absorption in this region, the better. On the other hand, 600 nm is a region having a red spectrum emitted from the phosphorescent organic EL device. By absorbing as much light as possible in this region, the color temperature of the phosphorescent organic EL device is increased. can do.

  More preferably, the expression 2 is satisfied.

A600 / A450> 2 Formula 2
In order to satisfy such an expression, the maximum of the absorption spectrum of the p-type semiconductor material is preferably 700 nm or more.

<N-type semiconductor material>
The n-type semiconductor material used for the bulk heterojunction layer of the present invention is not particularly limited. For example, fullerene, octaazaporphyrin and the like, p-type semiconductor perfluoro products (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalenetetra Examples include carboxylic acid anhydrides, naphthalenetetracarboxylic acid diimides, perylenetetracarboxylic acid anhydrides, aromatic carboxylic acid anhydrides such as perylenetetracarboxylic acid diimides, and polymer compounds containing the imidized product as a skeleton. Thus, a material having a light emission characteristic determined by a light emission wavelength characteristic of the organic EL element and a desired color temperature as illumination is selected. For example, in order to provide a lighting device as a white light source using a phosphorescent organic EL element, the following materials having a maximum value in light absorption characteristics in the red region are preferable.

  However, when the material having a thiophene-containing fused ring of the present invention is used as a p-type semiconductor material, a fullerene derivative capable of efficient charge separation is preferable. Fullerene derivatives include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotubes, multi-walled nanotubes, single-walled nanotubes, nanohorns (conical), and the like. Partially by hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, cycloalkyl group, silyl group, ether group, thioether group, amino group, silyl group, etc. Examples thereof include substituted fullerene derivatives.

  Among them, [6,6] -phenyl C61-butyric acid methyl ester (abbreviation PCBM), [6,6] -phenyl C61-butyric acid-nbutyl ester (PCBnB), [6,6] -phenyl C61-buty Rick acid-isobutyl ester (PCBiB), [6,6] -phenyl C61-butyric acid-n hexyl ester (PCBH), Adv. Mater. , Vol. 20 (2008), p2116, etc., aminated fullerenes such as JP-A 2006-199674, metallocene fullerenes such as JP-A 2008-130889, and cyclics such as US Pat. No. 7,329,709. It is preferable to use a fullerene derivative having a substituent and having improved solubility, such as fullerene having an ether group.

  Since the absorption spectrum of these fullerene derivatives is in the ultraviolet to blue region, the n-type semiconductor material has a photoelectric conversion efficiency in order to improve the absorption spectrum of the phosphorescent organic EL device of the present invention to a desired color temperature. It is preferable to reduce the addition amount as long as it does not fall too much. A preferable ratio of the p-type semiconductor material and the n-type semiconductor material in the bulk heterojunction layer is 4: 5 to 4: 1, and more preferably 5: 4 to 2: 1.

<Flexible transparent film>
A 110 nm indium tin oxide (ITO) transparent conductive film deposited on a PEN film substrate with a barrier layer having a size of 10 cm × 10 cm (sheet resistance 13Ω / □) Was used, and a flexible transparent substrate 311 with a transparent electrode was formed by patterning at a central portion with a width of 5 cm.

[Production of Lighting Device of Comparative Example and Lighting Device According to the Present Invention]
<Lighting Device A of Comparative Example>
An indium tin oxide (ITO) transparent conductive film deposited on a PEN substrate having a size of 5 cm × 6 cm with a thickness of 150 nm (sheet resistance 13 Ω / □) is 30 mm by using a normal photolithography technique and hydrochloric acid etching. The first electrode was formed by patterning to the width.

  The patterned transparent electrode was cleaned in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen, and finally with ultraviolet ozone cleaning.

  This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus.

  Each of the vapor deposition crucibles in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an optimum amount for producing an organic EL element. As the evaporation crucible, one made of a resistance heating material made of molybdenum or tungsten was used.

Subsequently, after depressurizing to a vacuum degree of 4 × 10 ⁻⁴ Pa, each layer was formed in the following order and composition to prepare the organic EL member 2.

Hole injection layer: m-MTDATA ... 40 nm
Hole transport layer: α-NPD: 10 nm
Light emitting layer (1): Compound 1 (97%), BD-1 (3%)... 15 nm
Intermediate layer (1): Compound 1 ... 5 nm
Light emitting layer (2): Compound 1 (92%), Ir-9 (8%)... 5 nm
Intermediate layer (2): Compound 1 3 nm
Light emitting layer (3): Compound 1 (94%), Ir-1 (5%), Bt ₂ Ir (acac) (1%)... 5 nm
Hole blocking layer: BAlq ... 15nm
Electron transport layer: BCP (75%), Cs (25%) ... 50 nm
Cathode: Aluminum ... 110nm

The light emitting surface side of the obtained organic EL element 22 uses a PET film on which SiO ₂ is formed as a barrier layer, and the cathode side uses a 40 μm thick aluminum foil sheet, and is a UV curable resin (manufactured by Nagase ChemteX Corporation). , UV RESIN XNR5570-B1) was used to make a lighting device 1. The sealing operation was performed in a glove box (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element into contact with the atmosphere.

<Lighting device B of Example 1 according to the present invention>
First, the organic EL member 2 was produced as shown below. Although it is different in the following points, it was produced in the same manner as the organic EL member 2 shown in the illumination device A of the comparative example except for that.

  After depositing up to the electron transport layer, the thickness of the cathode aluminum is 5 nm, and silver is deposited by 200 nm so as to form a grid line of 50 μm width for each 1 mm width as an auxiliary electrode line. The difference is EL.

  Subsequently, the organic photoelectric conversion member 3 was produced as shown below.

  After performing the cleaning and PEDOT layer forming process on the same film substrate as in the case of the organic EL member 2, the film substrate is measured under a nitrogen atmosphere in accordance with JIS B9920, the measured cleanliness is class 10, and the dew point temperature is It moved to the glove box of -80 degrees C or less and oxygen concentration 0.8ppm.

  In a glove box, a coating liquid for a bulk heterojunction layer was prepared as follows, and applied with a spin coater under conditions of 500 rpm and 60 seconds. After a bulk heterojunction layer was provided, the coating liquid was dried at room temperature for 30 minutes. .

(Bulk heterojunction layer coating solution)
Chlorobenzene 1.0g
PCPDTBT (showing the structural formula below) ... 14mg
(Synthesis with reference to Adv.Matter.2006, vol.18, p2884)
Aldrich PCBM 7mg
The substrate provided up to the bulk heterojunction layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. In addition, lithium fluoride was put in a resistance heating boat made of tantalum, and aluminum was put in a resistance heating boat made of tungsten, and was attached in a vapor deposition machine.

  Subsequently, the resistance heating boat made of tantalum was energized and heated, and an electron injection layer of lithium fluoride was provided to 0.5 nm on the substrate. Subsequently, the tungsten tantalum heating boat was energized and heated, and a cathode having a film thickness of 100 nm and a width of 5 cm was deposited at a deposition rate of 1 to 2 nm / second so as to be orthogonal to the transparent conductive film.

  The obtained organic EL member 2 and organic photoelectric conversion member 3 were laminated and sealed in the following order, and then taken out into the atmosphere to obtain a lighting device.

1) Set 40 μm-thick aluminum foil as a barrier film and apply a UV curable adhesive for sealing 2) The cathode side of the organic photoelectric conversion element 32 is made of an aluminum foil coated with a UV curable adhesive. Set on the surface 3) Set the organic EL element 22 on the surface of the organic photoelectric conversion member 3 with the PEN film side of the organic EL element 22 facing the organic photoelectric conversion member 3 4) UV curable adhesive for sealing A transparent gas barrier film coated with an agent is set on the surface of the organic EL member 2, and the laminate of aluminum foil / organic photoelectric conversion member 3 / organic EL member 2 is covered with the transparent gas barrier film and irradiated with UV for a predetermined time. Is cured and sealed.

  Here, the aluminum foil is used as an inexpensive non-transparent sealing material without water vapor permeability.

<The illuminating device C of Example 2 which concerns on this invention>
In the production of the organic photoelectric conversion element 32, the film thickness of the cathode aluminum is set to 5 nm, and silver is evaporated to 200 nm so as to form a grid line of 50 μm width for each 1 mm width as an auxiliary electrode line. An organic photoelectric conversion member 3 was produced in the same manner except that the organic photoelectric conversion element was used.

  The obtained organic photoelectric conversion member 3 and organic EL member 2 were laminated and sealed in the following order, and then taken out into the atmosphere to obtain a lighting device.

1) Set 40 μm-thick aluminum foil as a barrier film and apply a UV curable adhesive for sealing 2) The cathode side of the organic photoelectric conversion element 32 is made of an aluminum foil coated with a UV curable adhesive. Set on the surface 3) Set the organic EL element 2 on the surface of the organic photoelectric conversion member 3 with the PEN film side of the organic EL element 22 facing the organic photoelectric conversion member 4) UV curable adhesive for sealing A transparent gas barrier film coated with an agent is set on the surface of the organic EL member 2, the laminate composed of the organic EL member 2 / organic photoelectric conversion member 3 / aluminum foil is covered with the transparent gas barrier film, and UV is irradiated for a predetermined time. Is cured and sealed.

<The illuminating device D of Example 3 which concerns on this invention>
In the production of the organic photoelectric conversion element 32, the organic photoelectric conversion member 3 was produced in the same manner except that the p-type semiconductor material was changed to PCDTBT (synthesised with reference to Adv. Mater. 2007, 19, 2295).

  The obtained organic photoelectric conversion member 3 and organic EL member 2 were laminated and sealed in the following order, and then taken out into the atmosphere to obtain a lighting device.

1) Set 40 μm-thick aluminum foil as a barrier film and apply a UV curable adhesive for sealing 2) The cathode side of the organic photoelectric conversion element 32 is made of an aluminum foil coated with a UV curable adhesive. 3) Set on the surface of the organic photoelectric conversion member 3 with the PEN film side of the organic EL element 22 facing the organic photoelectric conversion member 3 4) Apply a UV curable adhesive for sealing A transparent gas barrier film is set on the surface of the organic EL element 22, the laminate composed of the aluminum foil / organic photoelectric conversion member 3 / organic EL member 2 is covered with the transparent gas barrier film, and cured by irradiating with UV for a predetermined time. , Seal.

[Evaluation of Lighting Device A of Comparative Example and Lighting Devices B to D of Examples of the Present Invention]
<Evaluation method of emission spectrum, absorption spectrum, color temperature, color rendering index>
Using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.), the front luminance, chromaticity, and emission spectrum of each lighting device A, B, C, and D were measured, and the 2 ° viewing angle front luminance 1000 cd / The value at m ² was evaluated, and the color temperature and the color rendering index were calculated for the illumination device A of the comparative example and the illumination devices B, C, and D of the examples.

  The absorption spectrum of the organic photoelectric conversion element 32 was measured using a spectrophotometer U-3300 manufactured by Hitachi High-Tech Co., Ltd., and the absorbance at 450 nm was compared with the absorbance at 600 nm.

<Evaluation Method of Photoelectric Conversion Efficiency Regarding Lighting Devices B to D of Examples>
Photoelectric conversion based on the emission energy when the organic photoelectric conversion element 32 used in the illumination devices B, C, and D of each example is irradiated with the organic EL element 22 at the 2 ° viewing angle front luminance of 1000 cd / m ^2. Efficiency was calculated.

<Evaluation results of lighting device A of comparative example and lighting devices B to D according to the present invention>
FIG. 7 shows emission spectra of the illumination device A of the comparative example and the illumination devices B to D of the examples according to the present invention.

  Table 1 shows the evaluation results regarding the illumination characteristics obtained for the illumination device A of the comparative example and the illumination devices B to D of the examples according to the present invention. “Wavelength λmax” in Table 1 is a wavelength indicating a maximum value in the absorption spectrum of the organic photoelectric conversion element 32 used in the illumination devices B to D of the examples.

  FIG. 7 shows the light spectrum of the illumination light emitted from the illumination devices of the examples and comparative examples according to the present invention. A thick broken line curve 1 shows a spectrum of the illumination device A of the comparative example. A thin solid curve 2 indicates the spectral spectrum of the illumination device B according to the embodiment of the present invention, and a thin broken curve 3 indicates the spectral spectrum of the illumination device C according to the embodiment of the present invention. Curve 4 shows the spectral spectrum of the illumination device D of the embodiment according to the present invention.

  As shown in FIG. 7 and Table 1, it can be seen that in each lighting device according to the present invention, the light spectrum on the long wave side is reduced and the color temperature is improved. In addition to simply cutting off light having a long wavelength, 4.7 to 6.4% of the light emitted from the organic EL element 22 to the organic photoelectric conversion element 32 is generated as reusable electricity. ing.

  Among them, the lighting device B of the first embodiment and the lighting device C of the second embodiment, in which the organic photoelectric conversion element 32 having strong light absorption characteristics in the long wavelength region is used, not only improve the color temperature but also the average color rendering. The index has also been improved, realizing a more preferable lighting device.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Organic EL member 22 Organic EL element 3 Organic photoelectric conversion member 32 Organic photoelectric conversion element 8 Power storage means 21 Film base material 221 Organic EL layer 61 Gas barrier film C Supply circuit

Claims (14)

An organic electroluminescent element that emits light of a first color temperature as a light source for illumination by supplying power;
An organic photoelectric conversion element that generates electricity by absorbing a part of the light emitted by the organic electroluminescence element;
A lighting device comprising:
An illumination device, wherein a color temperature of illumination light emitted to the outside by light absorption of the organic photoelectric conversion element is changed to a second color temperature higher than the first color temperature.   The illumination device according to claim 1, wherein a difference between the second color temperature and the first color temperature is 200K or more.   The average color rendering index of light emitted from the organic electroluminescence device converts the average color rendering index of illumination light emitted to the outside by light absorption of the organic photoelectric conversion device into a higher value. The lighting device according to 1 or 2.   4. The lighting device according to claim 1, further comprising a supply circuit that supplies electric power generated by the organic photoelectric conversion element to the organic electroluminescence element. 5.   It has an electrical storage part which stores the electric power generated by the said organic photoelectric conversion element, The illuminating device of any one of Claim 1 to 4 characterized by the above-mentioned.   The lighting device according to claim 1, wherein the organic electroluminescent element has a light emitting layer containing a phosphorescent material.   The lighting device according to any one of claims 1 to 6, wherein the organic photoelectric conversion element has a bulk heterojunction layer having a fullerene derivative. The illumination device according to claim 1, wherein an absorption spectrum of the organic photoelectric conversion element satisfies the following formula 1.
Formula 1 A600 / A450> 1
A450 is an absorption value at a wavelength of 450 nm, and A600 is an absorption value at a wavelength of 600 nm.   9. The illumination device according to claim 1, wherein the maximum of the absorption spectrum of the organic photoelectric conversion element is 700 nm or more.   The lighting device according to any one of claims 1 to 9, wherein the organic electroluminescence element or the organic photoelectric conversion element is covered with a gas barrier film.   The lighting device according to any one of claims 1 to 10, wherein the organic electroluminescent element and the organic photoelectric conversion element are integrally laminated. A reflective layer that reflects light emitted from the organic electroluminescent device to the outside;
The lighting device according to any one of claims 1 to 10, wherein the reflective layer, the organic electroluminescent element, and the organic photoelectric conversion element are arranged in this order.   The organic electroluminescence device and the organic photoelectric conversion device use a common transparent base material, the organic electroluminescence device is disposed on one side of the base material, and the organic photoelectric conversion device is disposed on the other side of the base material. The lighting device according to claim 12, wherein the lighting device is disposed.   The organic electroluminescence device and the organic photoelectric conversion device are formed by a solution process in which a coating liquid, which is a liquid composition, is applied to a substrate by a coating unit to form a coating film layer. 14. The lighting device according to any one of 1 to 13.

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