Light emitting element and light emitting device

Abstract

A light emitting element includes: a first light emitting layer having first quantum dots and emitting first light containing a first peak wavelength; a second light emitting layer having second quantum dots and emitting second light containing a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; a substrate on a surface of which the first light emitting layer and the second light emitting layer are adjacently arranged in a first direction; and a first bank provided on the substrate so as to separate the first light emitting layer and the second light emitting layer, the first bank transmitting the first light.

Description

Technical Field

[0001] This invention relates to light-emitting elements and light-emitting devices. Background Technology

[0002] Patent Document 1 discloses a light-emitting device comprising a light-emitting layer disposed on a substrate and a barrier on the substrate separating the light-emitting layer from each sub-pixel. Patent Document 1 also discloses a configuration in which a reflective portion is provided on the barrier to contact the organic light-emitting layer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-004724 Summary of the Invention

[0006] The technical problem to be solved by the present invention

[0007] However, the aforementioned patent document 1 has the following problem: a portion of the light emitted by the light-emitting layer that propagates in the in-plane direction of the light-emitting surface of the light-emitting device is reflected by the interface between the organic light-emitting layer and the electrodes on the organic light-emitting layer, and does not emit to the outside.

[0008] The purpose of this disclosure is to provide a light-emitting element and a light-emitting device that can effectively utilize light propagating in the in-plane direction of the light-emitting surface of the light-emitting device.

[0009] Solution to the problem

[0010] One aspect of the light-emitting element disclosed herein includes: a first light-emitting layer having a first quantum dot and emitting first light having a first peak wavelength; a second light-emitting layer having a second quantum dot and emitting second light having a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; a substrate having the first light-emitting layer and the second light-emitting layer disposed adjacent to each other in a first direction on a surface; and a first barrier disposed on the substrate to separate the first light-emitting layer and the second light-emitting layer, the first barrier allowing the first light from the first light-emitting layer toward the second light-emitting layer to be transmitted.

[0011] Additionally, one aspect of the present disclosure relates to a light-emitting element comprising: a plurality of first light-emitting layers having quantum dots and emitting first light having a first peak wavelength; a substrate for arranging the plurality of first light-emitting layers in a row; and a dam disposed on the substrate in such a manner as to separate two adjacently arranged first light-emitting layers, the dam allowing the first light to be transmitted between the two first light-emitting layers.

[0012] Additionally, one embodiment of the light-emitting device disclosed herein includes: a thin-film transistor; and a light-emitting element electrically connected to the thin-film transistor. The light-emitting element includes: a first light-emitting layer having a first quantum dot and emitting first light having a first peak wavelength; a second light-emitting layer having a second quantum dot with a dot size larger than the first quantum dot and emitting second light having a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; a substrate on which the first light-emitting layer and the second light-emitting layer are arranged adjacent to each other in a first direction; and a first barrier on the substrate, disposed to separate the first light-emitting layer and the second light-emitting layer, the first barrier allowing the first light from the first light-emitting layer to pass through towards the second light-emitting layer. Attached Figure Description

[0013] Figure 1 This is a top view schematically showing the main components of the light-emitting device as illustrated in the embodiment.

[0014] Figure 2 yes Figure 1 The image shows a cross-sectional view (II-II) of the light-emitting device.

[0015] Figure 3 This is a top view schematically showing the main components of the light-emitting device involved in the modified embodiment 2.

[0016] Figure 4 yes Figure 3 The image shows a cross-sectional view of the light-emitting device along line IV-IV.

[0017] Figure 5 This is a top view schematically showing the main components of the light-emitting device involved in the modified embodiment 3.

[0018] Figure 6 yes Figure 5 The VI-VI cross-sectional view of the light-emitting device 1 shown.

[0019] Figure 7 yes Figure 5 The light-emitting device 1 shown is shown in sectional view VII-VII.

[0020] Figure 8 This is a cross-sectional view showing the main components of the light-emitting device involved in the modified example 4 of the embodiment. Detailed Implementation

[0021] Hereinafter, embodiments illustrated in this disclosure will be described with reference to the accompanying drawings. Furthermore, the direction from the array substrate 2 (substrate) of the light-emitting device 1 toward the light-emitting element 3 will be referred to as "upper," and the opposite direction will be referred to as "lower." Additionally, identical reference numerals will be used to denote identical components in each drawing, and their descriptions will be omitted.

[0022] [Implementation Method] Figure 1 This is a top view schematically showing the main components of the light-emitting device 1 as illustrated in the embodiment. Figure 2 yes Figure 1 The image shows a cross-sectional view of the light-emitting device 1 along line II-II. The light-emitting device 1 can be used, for example, in the display of a television or smartphone. Furthermore, in... Figure 1 , Figure 2 In the image, arrows indicate the light L transmitted through dam 10.

[0023] like Figure 1 and Figure 2 As shown, the light-emitting device 1 includes a light-emitting element 3, which has a light-emitting layer 6. The light-emitting layer 6 contains quantum dots that emit light with peak wavelengths in the visible light range. The light-emitting layer 6 includes: a plurality of blue light-emitting layers 6B, each containing quantum dots that emit blue light with a peak wavelength of blue; a plurality of green light-emitting layers 6G, each containing quantum dots that emit green light L(G) with a peak wavelength of green; and a plurality of red light-emitting layers 6R, each containing quantum dots that emit red light L(R) with a peak wavelength of third quantum red. Furthermore, the dot size increases in the order of the quantum dots contained in each of the plurality of blue light-emitting layers 6B, the quantum dots contained in each of the plurality of green light-emitting layers 6G, and the quantum dots contained in each of the plurality of red light-emitting layers 6R. In this specification, in the relationship between the quantum dots contained in each of the plurality of blue light-emitting layers 6B and the quantum dots contained in each of the plurality of green light-emitting layers 6G or the plurality of red light-emitting layers 6R, the former are first quantum dots, and the latter are second quantum dots. Furthermore, in the relationship between the quantum dots contained in each of the multiple green emitting layers 6G and the quantum dots contained in each of the multiple red emitting layers 6R, the former are the first quantum dots, and the latter are the second quantum dots. In this specification, unless there is a specific need to distinguish between the blue emitting layer 6B, the green emitting layer 6G, and the red emitting layer 6R, they are simply referred to as emitting layer 6. Blue light L(B) refers to light whose peak wavelength is contained in the wavelength range of 400 nm to 500 nm. Green light L(G) refers to light whose peak wavelength is contained in the wavelength range of 500 nm to 600 nm. Red light L(R) refers to light whose peak wavelength is contained in the wavelength range of 600 nm to 780 nm. Figure 1 In the diagram, the blue emitting layer 6B, the green emitting layer 6G, and the red emitting layer 6R are represented by "B", "G", and "R", respectively.

[0024] Multiple blue light-emitting layers 6B, multiple green light-emitting layers 6G, and multiple red light-emitting layers 6R are arranged on the substrate surface of the array substrate 2 along the in-plane direction of the array substrate 2. Furthermore, in the light-emitting device 1 according to the embodiment, the multiple blue light-emitting layers 6B, green light-emitting layers 6G, and red light-emitting layers 6R form a light-emitting surface parallel to the in-plane direction of the array substrate 2.

[0025] Specifically, in Figure 1 In this embodiment, the left-right direction of the paper is taken as the horizontal axis direction (first direction) of the light-emitting device 1, and the direction orthogonal to this horizontal axis direction is taken as the vertical axis direction (second direction) of the light-emitting device 1. At this time, the blue light-emitting layer 6B, the green light-emitting layer 6G, and the red light-emitting layer 6R are arranged sequentially along the horizontal axis direction. Furthermore, multiple blue light-emitting layers 6B, multiple green light-emitting layers 6G, and multiple red light-emitting layers 6R are arranged along the vertical axis direction. In addition, in the light-emitting device 1 according to this embodiment, the multiple blue light-emitting layers 6B, multiple green light-emitting layers 6G, and multiple red light-emitting layers 6R correspond to each sub-pixel of the light-emitting device 1 and are separated by dikes 10.

[0026] (Light-emitting devices)

[0027] The following is for reference Figure 2 The detailed configuration of the light-emitting device 1 according to the embodiment is described below. The light-emitting device 1 has an array substrate 2 and light-emitting elements 3. The array substrate 2 is a glass substrate on which thin-film transistors (TFTs) for driving the light-emitting elements 3 are formed. Each layer of the light-emitting elements 3 is stacked on the array substrate 2.

[0028] The light-emitting element 3 has an anode 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, and a cathode 8. In the light-emitting device 1 according to the embodiment, the anode 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, and cathode 8 are stacked on the array substrate 2 from bottom to top.

[0029] Anode 4 is formed on array substrate 2 and is electrically connected to the TFT of array substrate 2. Anode 4 is, for example, a reflective substrate on array substrate 2, in which metals such as Al, Cu, Au, or Ag with high reflectivity of visible light and transparent materials such as ITO, IZO, ZnO, or BZO are stacked. Anode 4 can be formed, for example, by sputtering, vapor deposition, or other methods.

[0030] Hole transport layer 5 further transports holes injected from anode 4 to light-emitting layer 6. Hole transport layer 5 is formed on anode 4 and electrically connected to anode 4. Examples of hole transport layer 5 include: arylamine derivatives, anthracene derivatives, carbazole derivatives, thiophene derivatives, fluorene derivatives, stilbene derivatives, spirocyclic compounds, and metal oxides. Hole transport layer 5 can be produced by methods such as vapor deposition, printing, inkjet printing, spin coating, casting, dipping, rod coating, doctor blade coating, roller coating, gravure coating, flexographic printing, spraying, photolithography, or self-organizing methods (alternating adsorption method, self-organized monolayer method). Furthermore, hole transport layer 5 can also be composed of nanoparticles, crystals, polycrystalline, or amorphous materials.

[0031] In addition, a hole injection layer that promotes hole injection from the anode 4 can also be provided between the hole transport layer 5 and the anode 4, although not specifically illustrated.

[0032] The light-emitting layer 6 is disposed between the anode 4 and the cathode 8, and more specifically, between the hole transport layer 5 and the electron transport layer 7. The light-emitting layer 6 contains quantum dots (semiconductor nanoparticles) and is configured as having one or more layers of quantum dots stacked together. The light-emitting layer 6 can be formed from a dispersion of quantum dots in a solvent such as hexane or toluene using spin coating or inkjet printing. Alternatively, dispersing materials such as thiols or amines can be mixed into the dispersion.

[0033] Quantum dots are luminescent materials that possess both valence band and conduction band energy levels and emit light through the recombination of holes in the valence band and electrons in the conduction band. Due to the quantum confinement effect, the emission from quantum dots exhibits a narrow spectrum, thus enabling the production of light with relatively deep chromaticity.

[0034] Quantum dots can be, for example, semiconductor nanoparticles with a core / shell structure containing CdSe and a ZnS shell. Alternatively, quantum dots can also have a core / shell structure such as CdSe / CdS, InP / ZnS, ZnSe / ZnS, or CIGS / ZnS. Furthermore, ligands composed of organic compounds such as thiols or amines can be coordinated and bound to the outer periphery of the shell.

[0035] The particle size of quantum dots is approximately 3 nm to 15 nm. The emission wavelength from quantum dots can be controlled by the particle size of the quantum dots. Therefore, by controlling the particle size of the quantum dots, the wavelength of the light emitted by the light-emitting device 1 can be controlled.

[0036] The electron transport layer 7 is a transparent conductive film disposed on the light-emitting layer 6 and transports electrons injected from the cathode 8 to the light-emitting layer 6. The electron transport layer 7 may also have the function of suppressing hole transport to the cathode 8 (hole blocking function). Examples of electron transport layers 7 include: oxadiazoles, triazoles, phenanthrolines, silicon derivatives, cyclopentadiene derivatives, aluminum complexes, and metal oxides. Methods for forming the electron injection layer include, for example, vapor deposition, printing, inkjet printing, spin coating, casting, dipping, rod coating, doctor blade coating, roller coating, gravure coating, flexographic printing, spraying, photolithography, or self-organizing methods (alternating adsorption method, self-organized monolayer method), etc.

[0037] In addition, an electron injection layer may be provided between the electron transport layer 7 and the cathode 8, although not specifically illustrated, to facilitate the injection of electrons from the cathode 8.

[0038] The cathode 8 is disposed on and electrically connected to the electron transport layer 7. The cathode 8 can be made of, for example, a metal or a transparent material that has been thinned to a degree of light transmittance. Examples of metals constituting the cathode 8 include those containing Al, Ag, and Mg. Examples of transparent materials constituting the cathode 8 include ITO, IZO, ZnO, AZO, or BZO. The cathode 8 can be formed, for example, by sputtering or vapor deposition.

[0039] In the light-emitting device 1 having the above configuration, holes injected from the anode 4 and electrons injected from the cathode 8 are transported to the light-emitting layer 6 through the hole transport layer 5 and the electron transport layer 7, respectively. Then, the holes and electrons transported to the light-emitting layer 6 recombine within the quantum dot 61, thereby generating an exciton. Then, the quantum dot 61 emits light by returning from the excited state to the ground state through this exciton.

[0040] In addition, Figure 2 In the example, light emitted from the light-emitting layer 6 comes from the side opposite to the array substrate 2 (in Figure 2 The top-emitting light-emitting device 1 is taken from the top of the array substrate 2. However, the light-emitting device 1 can also be taken from the side of the array substrate 2. Figure 2 The bottom-emitting type of light is extracted from the bottom of the light source. When the light-emitting device 1 is configured as a bottom-emitting type, the cathode 8 is composed of a reflective electrode and the anode 4 is composed of a transparent electrode. In addition, the hole transport layer 5 is composed of a transparent conductive film.

[0041] Furthermore, the light-emitting device 1 according to the embodiment is formed by stacking an anode 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, and a cathode 8 sequentially from bottom to top on the array substrate 2. However, the light-emitting device 1 may also be formed by stacking a cathode 8, an electron transport layer 7, a light-emitting layer 6, a hole transport layer 5, and an anode 4 sequentially from bottom to top on the array substrate 2, i.e., an inverted configuration.

[0042] However, in the light-emitting device 1 according to the embodiment, a dam 10 is provided on the array substrate 2 to separate each blue light-emitting layer 6B, each green light-emitting layer 6G, and each red light-emitting layer 6R. The dam 10 includes a first dam region 11 (first dam), a second dam region 12 (second dam), and a third dam region 13. Hereinafter, each dam region will be described.

[0043] (First Dike Area)

[0044] The first barrier region 11 is a region in the array substrate 2 that separates adjacent light-emitting layers 6 that emit light with different peak wavelengths. The first barrier region 11 is configured to allow light with a shorter peak wavelength (first light) emitted by the adjacent light-emitting layers 6 to pass through, while allowing light with a longer peak wavelength (second light) to pass through.

[0045] exist Figure 1 , Figure 2 In the illustrated light-emitting device 1, the first dam region 11 is a region that separates the adjacent blue light-emitting layer 6B (first light-emitting layer) and green light-emitting layer 6G (second light-emitting layer) arranged in the array substrate 2, and also separates the adjacent blue light-emitting layer 6B (first light-emitting layer) and red light-emitting layer 6R (second light-emitting layer). Furthermore, the first dam region 11 allows the transmission of blue light L(B) with a peak wavelength of blue from the blue light-emitting layer 6B toward the green light-emitting layer 6G. The region within the first dam region 11 that allows the transmission of blue light L(B) is referred to as the first dam region 11B. This first dam region 11B can be made of acrylic resin, epoxy resin, or polyimide, etc., which allows the transmission of blue light L(B).

[0046] That is, a portion of the blue light L(B) propagating in the in-plane direction of the light-emitting surface in the light-emitting element 3 is reflected and not extracted to the outside due to the refractive index difference at the interface between the transparent electrode, i.e., the cathode 8, disposed on the blue light-emitting layer 6B and the layer formed on top of it (especially air if no layer is formed). Therefore, in the light-emitting device 1 according to the embodiment, the blue light L(B) that is not extracted to the outside is configured to pass through the first dam region 11B and propagate to the red light-emitting layer 6R and the green light-emitting layer 6G disposed next to the blue light-emitting layer 6B, respectively.

[0047] Here, the red emitting layer 6R absorbs light below the peak wavelength that becomes red, and the green emitting layer 6G absorbs light below the peak wavelength that becomes green. Then, light is emitted by photoluminescence (PL).

[0048] Therefore, in the light-emitting device 1, the red light-emitting layer 6R and the green light-emitting layer 6G can absorb the blue light L(B) emitted by the blue light-emitting layer 6B, and emit the red light-emitting layer 6R and the green light-emitting layer 6G, respectively. Therefore, the light-emitting device 1 can reduce the voltage applied to the light-emitting layer 6 in order to emit the red light L(R) and the green light L(G).

[0049] For example, light-emitting devices emit blue light at 1000 cd / m². 2 (0.9μW / mm 2 The light emitted is at a brightness of 3.6 μW / mm². Furthermore, it is not configured to emit blue light propagating in the in-plane direction of the light-emitting surface to the outside. In other words, the proportion of blue light emitted to the outside is determined by the proportion of light totally internally reflected at the interface between the light-emitting layer and its upper layer. In this configuration, 20% of the emitted blue light is extracted to the outside of the light-emitting element 3, while 80% of the emitted blue light remains inside the light-emitting element 3. That is, 3.6 μW / mm². 2 The light remains inside the light-emitting element 3.

[0050] Here, in the green light-emitting layer 6G adjacent to the blue light-emitting layer 6B, the blue light L(B) remaining in the light-emitting element 3 is absorbed and emitted. In the light-emitting device 1, for 5μW / mm 2 Irradiation with light is expected to have a voltage reduction effect of 0.1V. Therefore, if the optical concentration of the first dam region 11B is set to 0, the voltage applied to emit green light in the green light-emitting layer 6G can be reduced by 0.1V.

[0051] Furthermore, the amount of voltage reduction depends on the optical density of the first dam region 11B. For example, when the optical density of the first dam region 11B is 1, the applied voltage can be reduced by 0.01V. Conversely, when the optical density of the first dam region 11B is 2, the applied voltage can be reduced by 0.001V.

[0052] Therefore, the optical density of the first dam region 11B is particularly preferably 1 or less. By setting the optical density of the first dam region 11B to 1 or less, a voltage of 0.01V or more can be reduced. Therefore, effective voltage reduction can be achieved in the light-emitting device 1.

[0053] Furthermore, to suppress reflection at the interface between the first dam region 11B and the blue emitting layer 6B, it is preferable that the refractive index of the first dam region 11B is the same as or close to the refractive index of the blue emitting layer 6B. Specifically, at the interface between the first dam region 11B and the blue emitting layer 6B, due to the difference in refractive index between the two layers, the proportion of blue light L(B) lost due to reflection is less than 1%. That is, the refractive index of the blue emitting layer 6B is set to n. QD Let the refractive index of the first dam region 11B be n. Then, from the refractive index n... QD The condition that the reflectivity (perpendicular incidence) of light incident from the blue luminescent layer 6B onto the first dam region 11B with refractive index n is less than 1% can be expressed by the following mathematical formula (1). (n QD -n) 2 / (n QD +n) 2 <0.01…(1) Therefore, the refractive index of the blue luminescent layer 6B and the refractive index of the first dam region 11B satisfy the relationship of the following mathematical expression (2) derived from the above mathematical expression (1). n QD ×9 / 11 <n<n QD ×11 / 9…(2)

[0054] (Second Dyke Area)

[0055] The second dam region 12 is a region that separates multiple light-emitting layers 6 that emit light of the same peak wavelength and are arranged adjacently to emit light of the same color. Figure 1 , Figure 2 In the light-emitting device 1 shown, a second dam region 12 is disposed between two blue light-emitting layers 6B arranged adjacent to each other in the longitudinal direction. Furthermore, the second dam region 12 allows blue light L(B) emitted by the two adjacent blue light-emitting layers 6B to be transmitted between each other to the adjacent blue light-emitting layers 6B.

[0056] Therefore, the light-emitting device 1 according to the embodiment can make the blue light-emitting layer 6B absorb light with a wavelength shorter than the peak wavelength of the blue light L(B) transmitted through the second dam region 12, and emit light through PL.

[0057] In addition, Figure 1 , Figure 2 In the light-emitting device 1 shown, a second dam region 12 is also disposed between two green light-emitting layers 6G arranged adjacent to each other in the longitudinal direction. Furthermore, the second dam region 12 allows green light L(G) containing a green peak wavelength emitted by the two adjacent green light-emitting layers 6G to be transmitted between each other into the adjacent green light-emitting layers 6G.

[0058] Therefore, the light-emitting device 1 according to the embodiment can make the green light-emitting layer 6G absorb light with a wavelength shorter than the peak wavelength of the green light L(G) transmitted through the second dam region 12, and emit light through PL.

[0059] In addition, Figure 1 , Figure 2 In the illustrated light-emitting device 1, a second dam region 12 is also disposed between two adjacent red light-emitting layers 6R arranged in the longitudinal direction. Furthermore, the second dam region 12 allows red light L(R) containing a red peak wavelength emitted by the two adjacent red light-emitting layers 6R to be transmitted between each other to the adjacent red light-emitting layers 6R. Therefore, the light-emitting device 1 according to the embodiment can cause the red light-emitting layers 6R to absorb light with a wavelength shorter than the red peak wavelength contained in the red light L(R) transmitted through the second dam region 12, and emit light via PL.

[0060] Therefore, in the light-emitting device 1 according to the embodiment, when two adjacent blue light-emitting layers 6B, two adjacent green light-emitting layers 6G, and two adjacent red light-emitting layers 6R emit light respectively, the voltage applied to each light-emitting layer 6 can be reduced.

[0061] Furthermore, the second embankment region 12 can be made of a transparent material that allows light emitted from adjacent blue emitting layers 6B, adjacent green emitting layers 6G, and adjacent red emitting layers 6R to transmit light between each other. As this transparent material, at least one resin selected from the group consisting of acrylic polymers, polysiloxanes, and polyimides is preferred.

[0062] (Third dike area)

[0063] Furthermore, the third dam region 13 is the remaining region after removing the first dam region 11 and the second dam region 12. In the light-emitting device 1 according to the embodiment, the third dam region 13 is the region that separates the green light-emitting layer 6G and the red light-emitting layer 6R arranged adjacent to each other on the array substrate 2. In addition, the third dam region 13 is the region that surrounds the blue light-emitting layer 6B, the green light-emitting layer 6G, and the red light-emitting layer 6R along the outer periphery of the array substrate 2.

[0064] The third embankment region 13 is configured such that light emitted from the green emitting layer 6G and the red emitting layer 6R, particularly light propagating in the in-plane direction along the emitting surface and not escaping outward, is reflected outward. Specifically, the sides that contact the green emitting layer 6G and the red emitting layer 6R of the third embankment region 13 are constructed to be inclined in the vertical direction. That is, as... Figure 2As shown, the cross-sectional shape of the third dam region 13 is a tapered shape that gradually tapers upwards from the array substrate 2. Furthermore, the third dam region 13 is made of a material that has extremely low or no light transmittance compared to other dam regions, thus reflecting most or all of the light emitted from the light-emitting layer 6. For example, the third dam region 13 may be made of a black resist or the like.

[0065] Thus, the third dam region 13 is configured to reflect light propagating in the in-plane direction along the luminescent surface in a manner that causes it to exit outward. Therefore, the light-emitting device 1 can effectively utilize the light emitted by the green luminescent layer 6G and the red luminescent layer 6R, respectively.

[0066] Furthermore, as described above, blue light L(B) emitted by the blue light-emitting layer 6B is propagated via the first dam region 11B to the green light-emitting layer 6G and the red light-emitting layer 6R adjacent to the blue light-emitting layer 6B, respectively. However, the light-emitting device 1 of this disclosure is not limited to this configuration and may also have the following configuration. That is, the first dam region 11 may also be a region disposed between the adjacent green light-emitting layer 6G and the red light-emitting layer 6R. In this case, the first dam region 11 is configured to transmit light with a peak wavelength lower than that of green. Furthermore, the region in the first dam region 11 that transmits light with a peak wavelength lower than that of green is called the first dam region 11G. And it may also be configured to allow green light L(G) emitted by the green light-emitting layer 6G to propagate via the first dam region 11G to the red light-emitting layer 6R adjacent to the green light-emitting layer 6G.

[0067] (Variation Example 1)

[0068] As described above, in the light-emitting device 1, the first barrier region 11B is configured to transmit light with peak wavelengths below the peak wavelength of blue. Here, in order to suppress color mixing caused by stray light, the first barrier region 11B is preferably configured such that the green light L(G) emitted by the green light-emitting layer 6G and the red light L(R) emitted by the red light-emitting layer 6R do not pass through the first barrier region 11B to the side of the blue light-emitting layer 6B. Therefore, in the light-emitting device 1 according to the modified example 1 of the embodiment, the first barrier region 11B is constituted by a blue color filter.

[0069] Thus, when the first dam region 11B is formed by a blue color filter, the first dam region 11B allows blue light L(B) emitted by the blue light-emitting layer 6B to be transmitted. Therefore, the light-emitting device 1 according to Modification 1 can allow blue light L(B) to propagate to both the green light-emitting layer 6G and the red light-emitting layer 6R. Furthermore, the first dam region 11B can absorb green light L(G) and red light L(R) from the green light-emitting layer 6G and the red light-emitting layer 6R toward the blue light-emitting layer 6B. Therefore, the light-emitting device 1 according to Modification 1 can suppress green light L(G) and red light L(R) from entering the blue light-emitting layer 6B. Therefore, the light-emitting device 1 according to Modification 1 can suppress color mixing caused by stray light. Furthermore, when the first dam region 11 is set as the first dam region 11G, the first dam region 11G is formed by a green color filter.

[0070] (Variation Example 2)

[0071] In the light-emitting device 1 according to the above embodiment, the green light-emitting layer 6G and the red light-emitting layer 6R, which are arranged adjacently, are separated by a third dike region 13. In contrast, in the light-emitting device 1 according to the modified embodiment 2, the dike 10 separating the adjacent green light-emitting layer 6G and the red light-emitting layer 6R is also configured as a first dike region 11 (first dike region 11G).

[0072] The following is for reference Figure 3 , Figure 4 The configuration of the light-emitting device 1 involved in the modified example 2 of the embodiment is explained. Figure 3 This is a top view schematically showing the main components of the light-emitting device 1 involved in the modified embodiment 2. Figure 4 yes Figure 3 The image shows a cross-sectional view of the light-emitting device 1 along line IV-IV. Furthermore, in... Figure 3 , Figure 4 In the image, arrows indicate the light L transmitted through dam 10. Additionally, in... Figure 3 In the diagram, the blue emitting layer 6B, the green emitting layer 6G, and the red emitting layer 6R are represented by "B", "G", and "R", respectively.

[0073] like Figure 3 , Figure 4 As shown, in the light-emitting device 1 according to Embodiment Modification 2, the barrier 10 separating the adjacent blue light-emitting layer 6B and green light-emitting layer 6G, and the barrier 10 separating the adjacent blue light-emitting layer 6B and red light-emitting layer 6R, are both composed of a first barrier region 11B. Furthermore, in the light-emitting device 1 according to Embodiment Modification 2, the barrier 10 separating the adjacent green light-emitting layer 6G and red light-emitting layer 6R is composed of a first barrier region 11G that transmits light with a peak wavelength lower than the peak wavelength of green light.

[0074] In the light-emitting device 1 according to Modification Example 2, the blue light L(B) emitted by the blue light-emitting layer 6B that propagates in the in-plane direction along the light-emitting surface can be absorbed by the green light-emitting layer 6G and the red light-emitting layer 6R, thereby emitting PL (Photo-Luminescence). Furthermore, the green light L(G) emitted by the green light-emitting layer 6G that propagates in the in-plane direction along the light-emitting surface can be absorbed by the red light-emitting layer 6R, thereby emitting PL. Therefore, the voltage applied to the light-emitting layer 6 can be further reduced.

[0075] Furthermore, in the light-emitting device 1 involved in Modification 2, the first dam region 11B can also be formed by a blue color filter and the first dam region 11G can be formed by a green color filter.

[0076] (Third variation)

[0077] In the light-emitting device 1 described above, the blue light L(B) emitted by the blue light-emitting layer 6B propagates in the in-plane direction along the light-emitting surface, passes through the first dam region 11B, and is directed toward the green light-emitting layer 6G and the red light-emitting layer 6R, which are respectively arranged adjacent to the blue light-emitting layer 6B.

[0078] In this configuration, when blue light L(B) passes through the first dam region 11B and propagates to the green emitting layer 6G and the red emitting layer 6R, the blue light L(B) extends and advances within the first dam region 11B. Therefore, a portion of the blue light L(B) advancing in the in-plane direction along the emitting surface sometimes fails to properly enter the green emitting layer 6G and the red emitting layer 6R.

[0079] Therefore, in the light-emitting device 1 according to the modified example 3 of the embodiment, the light waveguide layer 22 is formed in the first dam region 11B, and the region in which the blue light L(B) can propagate is configured.

[0080] Specifically, such as Figures 5-7 As shown, an optical waveguide layer 22 is formed in the first dam region 11B by connecting the blue light-emitting layer 6B to the green light-emitting layer 6G and the blue light-emitting layer 6B to the red light-emitting layer 6R. Figure 5 This is a top view schematically showing the main components of the light-emitting device 1 involved in the modified embodiment 3. Figure 6 yes Figure 5 The VI-VI cross-sectional view of the light-emitting device 1 shown. Figure 7 yes Figure 5 The image shows a cross-sectional view of the light-emitting device 1 along line VII-VII. Furthermore, in... Figure 5 and Figure 6In the image, arrows indicate the light L transmitted through the dam 10 (first dam region 11).

[0081] The optical waveguide layer 22 can be formed within the first dam region 11B as follows: First, a first resin layer 11B1 is deposited on the array substrate 2 to form the base portion of the first dam region 11B. The optical waveguide layer 22 is then deposited on the first resin layer 11B1. Next, a second resin layer 11B2 is deposited on the optical waveguide layer 22 to form the front portion of the first dam region 11B. Thus, the first resin layer 11B1 and the second resin layer 11B2 are deposited on the first dam region 11B in a manner that sandwiches the optical waveguide layer 22. Then, the two ends of the optical waveguide layer 22 are covered by a cover portion 11B3. Figure 7 The exposed portion of the left and right ends of the embankment. Then, the first embankment region 11B of the desired shape is obtained by patterning.

[0082] In the light-emitting device 1 according to the modified embodiment 3, the blue light L(B) emitted by the blue light-emitting layer 6B is efficiently propagated through the optical waveguide layer 22 to the green light-emitting layer 6G and the red light-emitting layer 6R arranged adjacent to the blue light-emitting layer 6B. Therefore, the light-emitting device 1 according to the modified embodiment 3 is configured such that the light-emitting layer 6 and the optical waveguide layer 22 satisfy the following conditions.

[0083] That is, in order to form a waveguide mode in the blue emitting layer 6B, the refractive index of the blue emitting layer 6B is set to be greater than the refractive index of the first adjacent layer (hole transport layer 5 and electron transport layer 7) stacked adjacent to the blue emitting layer 6B. Specifically, the refractive index of the blue emitting layer 6B is set to be at least 0.3% higher than the refractive indices of the hole transport layer 5 and electron transport layer 7 stacked adjacent to the blue emitting layer 6B. This set value (at least 0.3%) is calculated as the refractive index difference required to produce total internal reflection at the interface between the blue emitting layer 6B and the first adjacent layer (hole transport layer 5 and electron transport layer 7). Furthermore, the waveguide mode here means the mode in which light propagates within the optical waveguide 22 while undergoing total internal reflection at the interface between the optical waveguide 22 and the components (layers) of the first dam region 11 surrounding the optical waveguide 22.

[0084] Furthermore, the amount of confinement of the blue light L(B) propagating in the in-plane direction of the emitting surface within the blue emitting layer 6B depends on the thickness of the blue emitting layer 6B. Therefore, as a condition for forming a waveguide mode, the product of the thickness of the blue emitting layer 6B and its refractive index is set to be greater than half the wavelength of the emitted blue light L(B).

[0085] Furthermore, in order to form a waveguide mode in the optical waveguide layer 22, the refractive index of the optical waveguide layer 22 is set to be greater than the refractive index of the component surrounding the outer periphery of the optical waveguide layer 22 in the first dam region 11B. In this specification, the component surrounding the outer periphery of the optical waveguide layer 22 is, for example... Figure 7 As shown, a first resin layer 11B1, a second resin layer 11B2, and a cap 11B3 can be included. The optical waveguide layer 22 can be formed, for example, from TiO2, Nb2O5, Ta2O5, SiO2, MgF2, and Al2O3. Furthermore, the first resin layer 11B1 and the second resin layer 11B2 can be formed, for example, from acrylic polymers, polysiloxanes, and polyimides. The cap 11B3 can be formed, for example, from acrylic polymers, polysiloxanes, and polyimides. In this specification, the first resin layer 11B1, the second resin layer 11B2, and the cap 11B3 are sometimes collectively referred to as the second adjacent layer. Specifically, the refractive index of the optical waveguide layer 22 is set to be at least 0.3% higher than the refractive indices of the first resin layer 11B1 and the second resin layer 11B2 in the first dam region 11B adjacent to the optical waveguide layer 22. Furthermore, the refractive index is set to be 0.3% or higher than that of the cover portion 11B3 of the first dam region 11B. This set value (0.3% or higher) is calculated as the refractive index difference required to generate total internal reflection at the interface between the optical waveguide 22 and the second adjacent layers (first resin layer 11B1, second resin layer 11B2, and cover portion 11B3). Moreover, the amount of light confinement within the optical waveguide layer 22 depends on the thickness of the optical waveguide layer 22. Therefore, the product of the thickness and refractive index of the optical waveguide layer 22 is set to be greater than half the wavelength of the propagating blue light L(B). Furthermore, the optical waveguide layer 22 can be composed of at least one of TiO2, Nb2O5, Ta2O5, SiO2, MgF2, and Al2O3.

[0086] Furthermore, each layer is disposed between the optical waveguide layer 22 and the light-emitting layer 6 (blue light-emitting layer 6B, green light-emitting layer 6G, and red light-emitting layer 6R) such that the height difference between the upper and lower surfaces of each layer in the vertical direction is less than 0.3 nm. By setting the height difference between the optical waveguide layer 22 and the light-emitting layer 6 to less than 0.3 nm, scattering at the interface between the optical waveguide layer 22 and the light-emitting layer 6 can be prevented. Thus, by preventing scattering, light loss due to leakage absorbed by the light-emitting layer 6 can be suppressed. Furthermore, as a planarization process to set the height difference between the optical waveguide layer 22 and the light-emitting layer 6 to less than 0.3 nm, examples include plasma processing or CMP processing.

[0087] In addition, in order to suppress light reflection at the interface between the optical waveguide layer 22 and the light-emitting layer 6, it is preferable that the optical waveguide layer 22 and the light-emitting layer 6 have the same refractive index.

[0088] Furthermore, in the modified embodiment 3, the light-emitting device 1 can be configured in the light-emitting layer 6 (e.g., in...). Figure 6 In the example shown, the interface between the blue light-emitting layer 6B and the optical waveguide layer 22 forms a fine uneven structure, thereby suppressing the reflection of light at the interface between the light-emitting layer 6B and the optical waveguide layer 22.

[0089] (Variation Example 4)

[0090] In the light-emitting device 1 according to the above embodiment, the first dam region 11B is configured to transmit light with a peak wavelength lower than that of blue light. Here, from the viewpoint of suppressing color mixing and light loss, the first dam region 11B is particularly preferably configured to transmit light with a peak wavelength of blue light and reflect light other than blue light.

[0091] Therefore, in the light-emitting device 1 according to the modified example 4 of the embodiment, as Figure 8 As shown, the first dam region 11B is composed of a dielectric multilayer film. Figure 8 This is a cross-sectional view showing the main components of the light-emitting device 1 according to the modified example 4 of the embodiment. Figure 8 Is with Figure 2 Similarly, a cross-sectional view of the light-emitting device 1 is cut out at point II-II. Furthermore, in... Figure 8 In the image, arrows indicate the light L transmitted through the dam 10 (first dam region 11).

[0092] A dielectric multilayer film is a stack of optical thin films composed of various dielectric materials with different refractive indices. By appropriately setting the film thickness and the materials constituting the optical thin film, a dielectric multilayer film can transmit light only within a specific peak wavelength range and reflect light within other peak wavelength ranges. Therefore, in the light-emitting device 1 according to Modification Example 4, the dielectric multilayer film is constructed such that red light L(R) and green light L(G) are reflected while blue light L(B) is transmitted.

[0093] Specifically, the dielectric multilayer film constituting the first dam region 11B involved in Modified Example 4 is a stack formed by combining two or more layers of high refractive index layer 31 (first refractive index layer) and low refractive index layer 32 (second refractive index layer). That is, the dielectric multilayer film has TiO2 (185 nm thick) as the high refractive index layer 31 and MgF2 (295 nm thick) as the low refractive index layer 32. Furthermore, the dielectric multilayer film is formed by stacking the high refractive index layer 31 and the low refractive index layer 32. Figure 8 For ease of explanation, the diagram illustrates a dielectric multilayer film consisting of a total of 5 layers, with 3 high-refractive-index layers 31 and 2 low-refractive-index layers 32, but the diagram is not limited to this. The dielectric multilayer film is formed by combining at least the high-refractive-index layer 31 and the low-refractive-index layer 32. Particularly preferred is that, for the dielectric multilayer film, TiO2 (185 nm thick) is selected as the high-refractive-index layer 31, MgF2 (295 nm thick) is selected as the low-refractive-index layer 32, and the low-refractive-index layer 32 and the high-refractive-index layer 31 are alternately stacked in 11 or more layers.

[0094] Additionally, while the high refractive index layer 31 is formed from TiO2 as described above, it can also be formed from Nb2O5 or Ta2O5. Similarly, while the low refractive index layer 32 is formed from MgF2 as described above, it can also be formed from SiO2 or Al2O3.

[0095] In this way, when the first dam region 11B is composed of a dielectric multilayer film, the first dam region 11B is formed on another substrate in advance by a CVD method or the like. Then, the first dam region 11B formed on the other substrate is stacked on the array substrate 2 at an appropriate position by a transfer printing method or a manual printing method.

[0096] In addition, the elements appearing in the above-described embodiments and variations can be appropriately combined.

[0097] Explanation of reference numerals in the attached figures

[0098] 1. Light-emitting devices

[0099] 2. Array substrate

[0100] 3. Light-emitting element

[0101] 6. Light-emitting layer

[0102] 6B Blue Emitting Layer

[0103] 6G Green Emissive Layer

[0104] 6R Red Emissive Layer

[0105] 10 embankments

[0106] 11 First Dike Area

[0107] 11B First Dike Area

[0108] 11G First Dike Area

[0109] 11B1 High Refractive Index Layer

[0110] 11B2 Low Refractive Index Layer

[0111] 12 Second Dike Area

[0112] 13 Third Dike Area

[0113] 22 Optical waveguide layer

Claims

1. A light-emitting element, characterized in that, include: A first light-emitting layer having a first quantum dot and emitting first light containing a first peak wavelength; The second light-emitting layer has a second quantum dot and emits second light containing a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; A substrate on which the first light-emitting layer and the second light-emitting layer are arranged adjacent to each other in a first direction; as well as A first barrier is provided on the substrate to separate the first light-emitting layer from the second light-emitting layer. The first barrier allows the first light to pass through from the first light-emitting layer toward the second light-emitting layer. The first dam includes a color filter that allows the first light to pass through and absorbs the second light.

2. The light-emitting element according to claim 1, characterized in that, Regarding the first light-emitting layer and the first dam When the refractive index of the first light-emitting layer is set to n QD When the refractive index of the first dam is set to n, The first light-emitting layer and the first embankment are configured to satisfy n QD ×9 / 11 <n<n QD The relationship is ×11 / 9.

3. The light-emitting element according to claim 1, characterized in that, The first dam has an optical waveguide layer between the first light-emitting layer and the second light-emitting layer to guide the first light.

4. The light-emitting element according to claim 3, characterized in that, The refractive index of the optical waveguide layer is higher than that of the component surrounding the outer periphery of the optical waveguide layer at the first dam.

5. A light-emitting device, characterized in that, include: Thin-film transistors; as well as The light-emitting element according to any one of claims 1 to 4, wherein the light-emitting element is electrically connected to the thin-film transistor.

6. A light-emitting element, characterized in that, include: A first light-emitting layer having a first quantum dot and emitting first light containing a first peak wavelength; The second light-emitting layer has a second quantum dot and emits second light containing a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; A substrate on which the first light-emitting layer and the second light-emitting layer are arranged adjacent to each other in a first direction; as well as A first barrier is provided on the substrate to separate the first light-emitting layer from the second light-emitting layer. The first barrier allows the first light to pass through from the first light-emitting layer toward the second light-emitting layer. The first dam comprises a dielectric multilayer film that allows the first light to pass through and the second light to be reflected.

7. The light-emitting element according to claim 6, characterized in that, The dielectric multilayer film is a laminate formed by combining two or more layers of a dielectric film having a first refractive index layer and a dielectric film having a second refractive index lower than the first refractive index.

8. The light-emitting element according to claim 7, characterized in that, The first refractive index layer comprises at least one of TiO2, Nb2O5, and Ta2O5. The second refractive index layer contains at least one of SiO2, MgF2 and Al2O3.

9. A light-emitting device, characterized in that, include: Thin-film transistors; as well as The light-emitting element according to any one of claims 6 to 8, wherein the light-emitting element is electrically connected to the thin-film transistor.

10. A light-emitting element, characterized in that, include: A first light-emitting layer having a first quantum dot and emitting first light containing a first peak wavelength; The second light-emitting layer has a second quantum dot and emits second light containing a second peak wavelength, the second peak wavelength being a wavelength greater than the first peak wavelength; A substrate on which the first light-emitting layer and the second light-emitting layer are arranged adjacent to each other in a first direction; as well as A first barrier is provided on the substrate to separate the first light-emitting layer from the second light-emitting layer. The first barrier allows the first light to be transmitted from the first light-emitting layer toward the second light-emitting layer. On the surface of the substrate, a plurality of the first light-emitting layers are arranged in a second direction different from the first direction. The light-emitting element includes a second barrier, which is arranged to separate the plurality of adjacent first light-emitting layers. The second dam allows the first light incident on the adjacent first light-emitting layers to be transmitted.

11. A light-emitting device, characterized in that, include: Thin-film transistors; as well as The light-emitting element of claim 10, wherein the light-emitting element is electrically connected to the thin-film transistor.

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