Display device

Abstract

A display device according to an embodiment comprises: a substrate including a red light-emitting region, a green light-emitting region, and a blue light-emitting region; a transistor positioned on the substrate; a first light-emitting element electrically connected to the transistor and overlapping the blue light-emitting region; and a capping layer positioned on the first light-emitting element, wherein the first light-emitting element comprises a first electrode, a first light-emitting layer positioned on the first electrode, a first electron transport layer positioned on the first light-emitting layer, and a second electrode positioned on the first electron transport layer, a first protective layer is positioned at any one of the following positions: between the second electrode and the capping layer, between the second electrode and the first electron transport layer, and on an upper surface of the capping layer, and the first protective layer is spaced apart from the red light-emitting region and the green light-emitting region.

Description

display device

[0001] The present disclosure relates to a display device.

[0002] A light-emitting device is a device in which holes supplied from an anode and electrons supplied from a cathode combine within a light-emitting layer formed between the anode and cathode to form excitons, and when these excitons become stabilized, they emit light.

[0003] Light-emitting elements have many advantages, such as a wide viewing angle, fast response speed, thin thickness, and low power consumption, and are therefore widely used in various electrical and electronic devices, such as televisions, monitors, and mobile phones.

[0004] The embodiments are intended to provide a display device having improved lifespan and reliability of a light-emitting element.

[0005] A display device according to one embodiment includes a substrate including a red light emitting region, a green light emitting region, and a blue light emitting region, a transistor positioned on the substrate, a first light emitting element electrically connected to the transistor and overlapping the blue light emitting region, and a capping layer positioned on the first light emitting element, wherein the first light emitting element includes a first electrode, a first light emitting layer positioned on the first electrode, a first electron transport layer positioned on the first light emitting layer, and a second electrode positioned on the first electron transport layer, and a first protective layer is positioned between the second electrode and the capping layer, between the second electrode and the first electron transport layer, and on an upper surface of the capping layer, and the first protective layer is spaced apart from the red light emitting region and the green light emitting region.

[0006] The first protective layer may be positioned between the second electrode and the capping layer.

[0007] It may further include a blue color filter positioned between the first protective layer and the capping layer.

[0008] The first protective layer may be positioned between the first electron transport layer and the second electrode.

[0009] It may further include a blue color filter positioned between the first protective layer and the second electrode.

[0010] It may further include a second light-emitting element overlapping the red light-emitting region, and a third light-emitting element overlapping the green light-emitting region.

[0011] The second light-emitting element may include a second light-emitting layer including a first quantum dot, a second electron transport layer positioned on the second light-emitting layer, and a second electrode positioned on the second electron transport layer.

[0012] The second electron transport layer may include ZnMgO.

[0013] The third light-emitting element may include a third light-emitting layer including a second quantum dot, a third electron transport layer positioned on the third light-emitting layer, and a second electrode positioned on the third electron transport layer.

[0014] The third electron transport layer may include ZnMgO.

[0015] The first protective layer may include at least one of silicon nitride, silicon nitride, and silicon oxide.

[0016] The above first light-emitting layer may include an organic material.

[0017] The second electron transport layer and the third electron transport layer may comprise the same material.

[0018] The first electron transport layer may include a different material from the second electron transport layer.

[0019] The first electron transport layer, the second electron transport layer, and the third electron transport layer may be spaced apart from each other with a partition wall therebetween.

[0020] The first light-emitting element includes a first hole injection layer and a first hole transport layer, the second light-emitting element includes a second hole injection layer and a second hole transport layer, and the third light-emitting element includes a third hole injection layer and a third hole transport layer, wherein the first hole injection layer, the second hole injection layer, and the third hole injection layer are spaced apart from each other, and the first hole transport layer, the second hole transport layer, and the third hole transport layer can be spaced apart from each other.

[0021] A display device according to one embodiment includes a substrate including a red light emitting region, a green light emitting region, and a blue light emitting region, a plurality of transistors positioned on the substrate, a first light emitting element, a second light emitting element, and a third light emitting element each electrically connected to the plurality of transistors and emitting light of different colors, a capping layer positioned on the first light emitting element, the second light emitting element, and the third light emitting element, and a first protective layer positioned between the first light emitting element and the capping layer, wherein the first light emitting element includes a first electrode, a first light emitting layer positioned on the first electrode, a first electron transport layer positioned on the first light emitting layer, and a second electrode positioned on the first electron transport layer, the second light emitting element includes a second light emitting layer, the third light emitting element includes a third light emitting layer, and the first protective layer is spaced apart from the second light emitting layer and the third light emitting layer in a thickness direction of the substrate.

[0022] The display device further includes a partition wall positioned between the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer, and the second electrode and the capping layer can be positioned continuously across the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer.

[0023] The second light-emitting element further includes a second electron transport layer positioned on the second light-emitting layer, and the third light-emitting element further includes a third electron transport layer positioned on the third light-emitting layer, and the first electron transport layer, the second electron transport layer, and the third electron transport layer are spaced apart from each other with the above-described partition wall therebetween, and the second electron transport layer and the third electron transport layer may include the same material, and the second electron transport layer and the first electron transport layer may include different materials.

[0024] The display device may further include a blue color filter in contact with the first protective layer.

[0025] The blue color filter may be positioned on the second electrode, the first protective layer may be positioned on the blue color filter, and the capping layer may be positioned on the first protective layer.

[0026] According to the embodiments, the reliability of the display device can be improved by preventing damage to the third light-emitting layer located in the blue light-emitting region and improving defects in the electron transport layer located in the red light-emitting region and the green light-emitting region.

[0027] Figure 1 is a cross-sectional view of a display device according to one embodiment.

[0028] FIG. 2 is a flowchart of a method for manufacturing some components of a display device according to one embodiment.

[0029] FIG. 3 is a schematic drawing of a chamber for manufacturing a display device according to one embodiment.

[0030] Figures 4 and 5 are cross-sectional views of a display device according to another embodiment.

[0031] Fig. 6 is a cross-sectional view of a display device according to another embodiment.

[0032] FIG. 7 is a flowchart of a method for manufacturing some components of a display device according to the embodiment of FIG. 6.

[0033] FIGS. 8 and 9 are cross-sectional views of a display device according to another embodiment.

[0034] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0035] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0036] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0037] Furthermore, when we say that a layer, membrane, region, plate, or other part is "above" or "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there are other parts in between. Conversely, when we say that a part is "directly above" another part, we mean that there are no other parts in between. Furthermore, saying that a part is "above" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "above" or "on" the opposite direction of gravity.

[0038] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0039] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0040] Hereinafter, a display device according to an embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of a display device according to an embodiment, FIG. 2 is a flowchart of a method for manufacturing some components of a display device according to an embodiment, and FIG. 3 is a schematic diagram illustrating a chamber for manufacturing a display device according to an embodiment.

[0041] First, let us look at a display device according to one embodiment with reference to FIG. 1.

[0042] A display device according to one embodiment includes a red light emitting area (RLA), a green light emitting area (GLA), and a blue light emitting area (BLA). A non-emissive area (NLA) may be positioned between the red light emitting area (RLA), the green light emitting area (GLA), and the blue light emitting area (BLA). Each emissive area may correspond to a pixel. For example, the blue light emitting area (BLA), the red light emitting area (RLA), and the green light emitting area (GLA) may correspond to a blue pixel, a red pixel, and a green pixel, respectively. The shape and arrangement of each of the red light emitting area (RLA), the green light emitting area (GLA), and the blue light emitting area (BLA) may be variously modified.

[0043] A display device according to one embodiment includes a substrate (SUB). The substrate (SUB) may include a flexible material such as plastic that can be easily bent, folded, or rolled, or may include a rigid substrate.

[0044] A buffer layer (BF) may be positioned on the substrate (SUB). Depending on the embodiment, the buffer layer (BF) may be omitted. The buffer layer (BF) may be silicon nitride (SiN x ), silicon oxide (SiO2), or silicon oxynitride, etc. The buffer layer (BF) is located between the substrate (SUB) and the semiconductor layer (ACT), and blocks impurities from the substrate (SUB) during the crystallization process for forming polycrystalline silicon, thereby improving the characteristics of the polycrystalline silicon, and planarizes the substrate (SUB) to relieve the stress of the semiconductor layer (ACT) formed on the buffer layer (BF).

[0045] A semiconductor layer (ACT) is positioned on the buffer layer (BF). The semiconductor layer (ACT) may be made of polycrystalline silicon or an oxide semiconductor. The semiconductor layer (ACT) includes a channel region (C), a source region (S), and a drain region (D). The source region (S) and the drain region (D) are respectively positioned on both sides of the channel region (C). The channel region (C) is an intrinsic semiconductor that is not doped with impurities, and the source region (S) and the drain region (D) are impurity semiconductors that are doped with conductive impurities. The semiconductor layer (ACT) may also be made of an oxide semiconductor, in which case a separate protective layer (not shown) may be added to protect the oxide semiconductor material that is vulnerable to external environments such as high temperatures.

[0046] A gate insulator (GI) is located on top of the semiconductor layer (ACT). The gate insulator (GI) is made of silicon nitride (SiN x ), silicon oxide (SiO2), and silicon oxynitride, which may be a single layer or a multilayer.

[0047] A gate electrode (GE) is positioned on the gate insulating film (GI). The gate electrode (GE) may be a multi-film in which a metal film including any one of copper (Cu), a copper alloy, aluminum (Al), an aluminum alloy, molybdenum (Mo), and a molybdenum alloy is laminated.

[0048] An interlayer insulating film (IL1) is positioned on the gate electrode (GE) and the gate insulating film (GI). The interlayer insulating film (IL1) is made of silicon nitride (SiN x ), silicon oxide (SiO2), or silicon oxynitride, etc. The interlayer insulating film (IL1) has openings that expose the source region (S) and the drain region (D), respectively.

[0049] A source electrode (SE) and a drain electrode (DE) are positioned on an interlayer insulating film (IL1). The source electrode (SE) and the drain electrode (DE) are connected to the source region (S) and the drain region (D) of the semiconductor layer (ACT), respectively, through openings formed in the interlayer insulating film (IL1).

[0050] A protective film (IL2) is positioned on the interlayer insulating film (IL1), the source electrode (SE), and the drain electrode (DE). The protective film (IL2) covers and planarizes the interlayer insulating film (IL1), the source electrode (SE), and the drain electrode (DE), so that the first electrodes (E1a, E1b, E1c) can be formed on the protective film (IL2) without steps. This protective film (IL2) can be made of an organic material such as a polyacrylate resin or a polyimide resin, or a laminated film of an organic material and an inorganic material.

[0051] A first electrode (E1a, E1b, E1c) is positioned on the protective film (IL2). The first electrode (E1a, E1b, E1c) is connected to the drain electrode (DE) through an opening in the protective film (IL2).

[0052] The driving transistor, which is composed of a gate electrode (GE), a semiconductor layer (ACT), a source electrode (SE), and a drain electrode (DE), is connected to the first electrodes (E1a, E1b, E1c) and supplies a driving current to each light emitting element (ED). In addition to the driving transistor illustrated in FIG. 1, the display device according to the present embodiment may further include a switching transistor (not illustrated) that is connected to a data line and transmits a data voltage in response to a scan signal, and a compensation transistor (not illustrated) that is connected to the driving transistor and compensates for a threshold voltage of the driving transistor in response to a scan signal.

[0053] A partition wall (PDL) is positioned on the protective film (IL2) and the first electrodes (E1a, E1b, E1c). The partition wall (PDL) may overlap the first electrodes (E1a, E1b, E1c) and have pixel openings (OP1, OP2, OP3) that define a light-emitting area. The partition wall (PDL) may include an organic material such as a polyacrylate resin or a polyimide resin, or an inorganic material of a silica series. The pixel openings (OP1, OP2, OP3) may have a planar shape that is almost similar to the first electrodes (E1a, E1b, E1c), and may have a planar rhombus or an octagonal shape similar to a rhombus, but are not limited thereto and may have any shape such as a square or a polygon.

[0054] According to one embodiment, the first light-emitting element (ED1) may overlap with the blue light-emitting area (BLA), the second light-emitting element (ED2) may overlap with the red light-emitting area (RLA), and the third light-emitting element (ED3) may overlap with the green light-emitting area (GLA).

[0055] The first light-emitting element (ED1) includes a first electrode (E1a), a first hole injection layer (HIL1), a first hole transport layer (HTL1), a first light-emitting layer (EML1), a first electron transport layer (ETL1), and a second electrode (E2).

[0056] The second light-emitting element (ED2) includes a first electrode (E1b), a second hole injection layer (HIL2), a second hole transport layer (HTL2), a second light-emitting layer (EML2), a second electron transport layer (ETL2), and a second electrode (E2).

[0057] The third light-emitting element (ED3) includes a first electrode (E1c), a third hole injection layer (HIL3), a third hole transport layer (HTL3), a third light-emitting layer (EML3), a third electron transport layer (ETL3), and a second electrode (E2).

[0058] A partition wall (PDL) may be positioned between the blue light emitting area (BLA), the red light emitting area (RLA), and the green light emitting area (GLA). The partition wall (PDL) may include a first opening (OP1) overlapping the blue light emitting area (BLA), a second opening (OP2) overlapping the red light emitting area (RLA), and a third opening (OP3) overlapping the green light emitting area (GLA).

[0059] A first opening (OP1) and a first electrode (E1a) of a first light-emitting element (ED1) may overlap, a second opening (OP2) and a first electrode (E1b) of a second light-emitting element (ED2) may overlap, and a third opening (OP3) and a first electrode (E1c) of a third light-emitting element (ED3) may overlap. At least a portion of the first electrode (E1a) of the first light-emitting element (ED1), the first electrode (E1b) of the second light-emitting element (ED2), and the first electrode (E1c) of the third light-emitting element (ED3) may overlap a partition wall (PDL). The first electrode (E1a) of the first light-emitting element (ED1), the first electrode (E1b) of the second light-emitting element (ED2), and the first electrode (E1c) of the third light-emitting element (ED3) may be spaced apart from each other with respect to the partition wall (PDL).

[0060] A first hole injection layer (HIL1) may be positioned on a first electrode (E1a) of a first light-emitting element (ED1), a second hole injection layer (HIL2) may be positioned on a first electrode (E1b) of a second light-emitting element (ED2), and a third hole injection layer (HIL3) may be positioned on a first electrode (E1c) of a third light-emitting element (ED3). The first hole injection layer (HIL1), the second hole injection layer (HIL2), and the third hole injection layer (HIL3) may be spaced apart from each other with respect to a partition wall (PDL). The first hole injection layer (HIL1) may be positioned within a first opening (OP1), the second hole injection layer (HIL2) may be positioned within a second opening (OP2), and the third hole injection layer (HIL3) may be positioned within a third opening (OP3).

[0061] Each of the first hole injection layer (HIL1), the second hole injection layer (HIL2), and the third hole injection layer (HIL3) can be formed through an inkjet process. The first hole injection layer (HIL1), the second hole injection layer (HIL2), and the third hole injection layer (HIL3) may include the same material, but are not limited thereto, and may each include different materials.

[0062] Each of the first hole injection layer (HIL1), the second hole injection layer (HIL2), and the third hole injection layer (HIL3) may include a hole injection material. The hole injection material may be a phthalocyanine compound such as copper phthalocyanine; DNTPD(N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA(4,4',4"-[tris(3-methylphenyl)phenylamino] triphenylamine), TDATA(4,4'4"-Tris(N,N-diphenylamino)triphenylamine), 2-TNATA(4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS(Poly(3,4-ethylenedioxythiophene) / Poly(4-styrenesulfonate)), PANI / DBSA (Polyaniline / Dodecylbenzenesulfonic acid), PANI / CSA (Polyaniline / Camphor sulfonicacid), PANI / PSS (Polyaniline / Poly(4-styrenesulfonate)), It may include NPB (N,N'-di(naphthalene-l-yl)-N,N'-diphenyl-benzidine), NPD (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), polyether ketone containing triphenylamine (TPAPEK), 4-Isopropyl-4'-methyldiphenyliodonium [Tetrakis(pentafluorophenyl)borate], HAT-CN (dipyrazino[2,3-f: 2',3'-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile), etc.

[0063] A first hole transport layer (HTL1) may be positioned on a first hole injection layer (HIL1), a second hole transport layer (HTL2) may be positioned on a second hole injection layer (HIL2), and a third hole transport layer (HTL3) may be positioned on a third hole injection layer (HIL3). The first hole transport layer (HTL1), the second hole transport layer (HTL2), and the third hole transport layer (HTL3) may be spaced apart from each other with respect to a partition wall (PDL). The first hole transport layer (HTL1) may be positioned within a first opening (OP1), the second hole transport layer (HTL2) may be positioned within a second opening (OP2), and the third hole transport layer (HTL3) may be positioned within a third opening (OP3).

[0064] Each of the first hole transport layer (HTL1), the second hole transport layer (HTL2), and the third hole transport layer (HTL3) can be formed through an inkjet process. The first hole transport layer (HTL1), the second hole transport layer (HTL2), and the third hole transport layer (HTL3) can include the same material, but are not limited thereto, and may each include different materials.

[0065] Each of the first hole transport layer (HTL1), the second hole transport layer (HTL2), and the third hole transport layer (HTL3) may include a hole transport material. Hole transport materials include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalene-l-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4'-Bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), mCP (1,3-Bis(N-carbazolyl)benzene), It may include CzSi (9-(4-tert-Butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole), m-MTDATA (4,4',4"-[tris(3-methylphenyl)phenylamino] triphenylamine), etc.

[0066] A first light-emitting layer (EML1) may be positioned on a first hole transport layer (HTL1), a second light-emitting layer (EML2) may be positioned on a second hole transport layer (HTL2), and a third light-emitting layer (EML3) may be positioned on a third hole transport layer (HTL3). The first light-emitting layer (EML1), the second light-emitting layer (EML2), and the third light-emitting layer (EML3) may be spaced apart from each other with respect to a partition wall (PDL). The first light-emitting layer (EML1) may be positioned within a first opening (OP1), the second light-emitting layer (EML2) may be positioned within the second opening (OP2), and the third light-emitting layer (EML3) may be positioned within the third opening (OP3). Each of the first light-emitting layer (EML1), the second light-emitting layer (EML2), and the third light-emitting layer (EML3) may be manufactured through an inkjet process.

[0067] The first light-emitting layer (EML1), the second light-emitting layer (EML2), and the third light-emitting layer (EML3) can emit light of different colors.

[0068] The first light-emitting layer (EML1) can emit blue light. The first light-emitting layer (EML1) can include an organic material, and in particular, can be made of a low-molecular organic material or a high-molecular organic material such as PEDOT (Poly 3,4-ethylenedioxythiophene).

[0069] The second light-emitting layer (EML2) can emit red light. The second light-emitting layer (EML2) can include the first quantum dot. The third light-emitting layer (EML3) can emit green light. The third light-emitting layer (EML3) can include the second quantum dot.

[0070] Then, below, quantum dots including the first quantum dot and the second quantum dot are described in detail.

[0071] In this specification, quantum dots (hereinafter also referred to as semiconductor nanocrystals) may include a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element or compound, a group I-III-VI compound, a group II-III-VI compound, a group I-II-IV-VI compound, or a combination thereof.

[0072] The above II-VI group compound is a binary compound selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof; a ternary compound selected from the group consisting of AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof; And it may be selected from the group consisting of a four-element compound selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof. The group II-VI compound may further include a group III metal.

[0073] The above III-V group compound may be selected from the group consisting of binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs, InNSb, InPAs, InZnP, InPSb, and mixtures thereof; and quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, InZnP, and mixtures thereof. The above group III-V compound may further comprise a group II metal (e.g., InZnP).

[0074] The above IV-VI group compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof.

[0075] The above group IV element or compound may be selected from the group consisting of a single element compound selected from the group consisting of Si, Ge, and combinations thereof; and a binary element compound selected from the group consisting of SiC, SiGe, and combinations thereof, but is not limited thereto.

[0076] Examples of the Group I-III-VI compounds include, but are not limited to, CuInSe2, CuInS2, CuInGaSe, and CuInGaS. Examples of the Group I-II-IV-VI compounds include, but are not limited to, CuZnSnSe, and CuZnSnS. The Group IV element or compound may be selected from the group consisting of a single element selected from the group consisting of Si, Ge, and mixtures thereof; and a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0077] The above group II-III-VI compound may be selected from the group consisting of, but is not limited to, ZnGaS, ZnAlS, ZnInS, ZnGaSe, ZnAlSe, ZnInSe, ZnGaTe, ZnAlTe, ZnInTe, ZnGaO, ZnAlO, ZnInO, HgGaS, HgAlS, HgInS, HgGaSe, HgAlSe, HgInSe, HgGaTe, HgAlTe, HgInTe, MgGaS, MgAlS, MgInS, MgGaSe, MgAlSe, MgInSe, and combinations thereof.

[0078] The above group I-II-IV-VI compound may be selected from CuZnSnSe and CuZnSnS, but is not limited thereto.

[0079] In one embodiment, the quantum dot may not contain cadmium. The quantum dot may contain semiconductor nanocrystals based on a Group III-V compound including indium and phosphorus. The Group III-V compound may further contain zinc. The quantum dot may contain semiconductor nanocrystals based on a Group II-VI compound including a chalcogen element (e.g., sulfur, selenium, tellurium, or a combination thereof) and zinc.

[0080] In quantum dots, the aforementioned binary, ternary, and / or quaternary compounds may exist within the particle at a uniform concentration, or may exist within the same particle with partially different concentration distributions. Furthermore, one quantum dot may have a core / shell structure surrounding another quantum dot. The interface between the core and shell may have a concentration gradient, with the concentration of the element in the shell decreasing toward the center.

[0081] In some embodiments, the quantum dot may have a core-shell structure comprising a core including the aforementioned nanocrystals and a shell surrounding the core. The shell of the quantum dot may function as a protective layer to maintain semiconductor properties by preventing chemical modification of the core and / or as a charging layer to impart electrophoretic properties to the quantum dot. The shell may be a single layer or a multilayer. The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. Examples of the shell of the quantum dot include a metal or non-metal oxide, a semiconductor compound, or a combination thereof.

[0082] For example, the oxide of the metal or non-metal may be a binary compound such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, NiO, or a ternary compound such as MgAl2O4, CoFe2O4, NiFe2O4, CoMn2O4, but the present invention is not limited thereto.

[0083] In addition, the semiconductor compound may be exemplified by CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but the present invention is not limited thereto.

[0084] The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. In addition, the semiconductor nanocrystal may have a structure including a single semiconductor nanocrystal core and a multilayer shell surrounding the core. In one embodiment, the multilayer shell may have two or more layers, for example, two, three, four, five, or more layers. Adjacent two layers of the shell may have a single composition or different compositions. Each layer in the multilayer shell may have a composition that varies along the radius.

[0085] Quantum dots can have a full width of half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, preferably about 40 nm or less, and more preferably about 30 nm or less, and color purity and color reproducibility can be improved within this range. In addition, since light emitted by these quantum dots is emitted in all directions, a wide viewing angle can be improved.

[0086] The quantum dot may have different energy band gaps for the shell material and the core material. For example, the energy band gap of the shell material may be larger than that of the core material. In another embodiment, the energy band gap of the shell material may be smaller than that of the core material. The quantum dot may have a multilayer shell. In the multilayer shell, the energy band gap of the outer layer may be larger than that of the inner layer (i.e., the layer closer to the core). In the multilayer shell, the energy band gap of the outer layer may be smaller than the energy band gap of the inner layer.

[0087] Quantum dots can have their absorption / emission wavelengths controlled by adjusting their composition and size. The maximum emission peak wavelength of the quantum dots can range from ultraviolet to infrared wavelengths or even beyond.

[0088] Quantum dots can have a quantum efficiency of greater than or equal to about 10%, for example, greater than or equal to about 30%, greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 90%, or even greater than or equal to 100%. Quantum dots can have a relatively narrow spectrum. Quantum dots can have a half-width of an emission wavelength spectrum of, for example, less than or equal to about 50 nm, less than or equal to about 45 nm, less than or equal to about 40 nm, or less than or equal to about 30 nm.

[0089] The quantum dot may have a particle size of about 1 nm or more and about 100 nm or less. The particle size refers to the diameter of the particle or the diameter converted assuming a spherical shape from a two-dimensional image obtained by transmission electron microscopy analysis. The quantum dot may have a size of about 1 nm to about 20 nm, for example, 2 nm or more, 3 nm or more, or 4 nm or more and 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, for example, 10 nm or less. The shape of the quantum dot is not particularly limited. For example, the shape of the quantum dot may include, but is not limited to, a sphere, a polyhedron, a pyramid, a multipod, a square, a rectangular parallelepiped, a nanotube, a nanorod, a nanowire, a nanosheet, or a combination thereof.

[0090] Quantum dots are commercially available or can be synthesized appropriately. During colloidal synthesis, the particle size of quantum dots can be relatively freely controlled, and the particle size can be uniformly controlled.

[0091] The quantum dot may include an organic ligand (e.g., having a hydrophobic moiety and / or a hydrophilic moiety). The organic ligand moiety may be bonded to the surface of the quantum dot. The organic ligand includes RCOOH, RNH2, R2NH, R3N, RSH, R3PO, R3P, ROH, RCOOR, RPO(OH)2, RHPOOH, R2POOH, or a combination thereof, wherein R may each independently be a substituted or unsubstituted C3 to C40 (e.g., at least C5 and at most C24) alkyl, a substituted or unsubstituted C3 to C40 aliphatic hydrocarbon group such as a substituted or unsubstituted alkenyl, a substituted or unsubstituted C6 to C40 aromatic hydrocarbon group such as a substituted or unsubstituted C6 to C40 aryl group, or a combination thereof.

[0092] Examples of the organic ligand include thiol compounds such as methanethiol, ethanethiol, propanethiol, butanethiol, pentanethiol, hexanethiol, octanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, and benzylthiol; amines such as methaneamine, ethaneamine, propaneamine, butaneamine, pentylamine, hexylamine, octylamine, nonylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, tributylamine, and trioctylamine; carboxylic acid compounds such as methanoic acid, ethanoic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, and benzoic acid; Phosphine compounds such as methyl phosphine, ethyl phosphine, propyl phosphine, butyl phosphine, pentyl phosphine, octylphosphine, dioctyl phosphine, tributylphosphine, trioctylphosphine, etc.; Phosphine compounds or oxide compounds thereof such as methyl phosphine oxide, ethyl phosphine oxide, propyl phosphine oxide, butyl phosphine oxide, pentyl phosphine oxide, tributylphosphine oxide, octylphosphine oxide, dioctyl phosphine oxide, trioctylphosphine oxide; Diphenyl phosphine, triphenyl phosphine compounds or oxide compounds thereof; C5 to C20 alkyl phosphinic acids, C5 to C20 alkyl phosphonic acids, etc., such as hexylphosphinic acid, octylphosphinic acid, dodecanephosphinic acid, tetradecanephosphinic acid, hexadecanephosphinic acid, octadecanephosphinic acid; etc., but are not limited thereto. Quantum dots may contain hydrophobic organic ligands alone or in a mixture of one or more. The hydrophobic organic ligands may not contain photopolymerizable moieties (e.g., acrylate groups, methacrylate groups, etc.).

[0093] Referring back to FIG. 1, a first electron transport layer (ETL1) may be positioned on a first light-emitting layer (EML1), a second electron transport layer (ETL2) may be positioned on a second light-emitting layer (EML2), and a third electron transport layer (ETL3) may be positioned on a third light-emitting layer (EML3). The first electron transport layer (ETL1), the second electron transport layer (ETL2), and the third electron transport layer (ETL3) may be spaced apart from each other with respect to a partition wall (PDL). The first electron transport layer (ETL1) may be positioned within a first opening (OP1), the second electron transport layer (ETL2) may be positioned within a second opening (OP2), and the third electron transport layer (ETL3) may be positioned within a third opening (OP3).

[0094] The first electron transport layer (ETL1), the second electron transport layer (ETL2), and the third electron transport layer (ETL3) may each be formed through an inkjet process. In one embodiment, the second electron transport layer (ETL2) and the third electron transport layer (ETL3) may include the same electron transport material. The first electron transport layer (ETL1) may include a different electron transport material from the second electron transport layer (ETL2) and the third electron transport layer (ETL3).

[0095] The first electron transport layer (ETL1) may include a triazine-based compound or an anthracene-based compound, depending on the embodiment. However, the electron transport material is not limited thereto, and examples thereof include Alq3(Tris(8-hydroxyquinolinato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene, TPBi(1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene), BCP(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen(4,7-Diphenyl-1,10-phenanthroline), TAZ(3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ(4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD(2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq(Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-Biphenyl-4-olato)aluminum), Bebq2(berylliumbis(benzoquinolin-10-olate), ADN(9,10-di(naphthalene-2-yl)anthracene), TSPO1(diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide), TPM-TAZ (2,4,6-Tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine) and mixtures thereof.Meanwhile, the second electron transport layer (ETL2) and the third electron transport layer (ETL3) may include ZnMgO.

[0096] A second electrode (E2) may be positioned on the first electron transport layer (ETL1), the second electron transport layer (ETL2), and the third electron transport layer (ETL3). The second electrode (E2) may be positioned continuously across the blue light emitting region (BLA), the red light emitting region (RLA), the green light emitting region (GLA), and the non-emitting region (NLA). The second electrode (E2) may receive a common voltage through a common voltage transmission part (not shown) of the non-display region.

[0097] Here, the first electrode (E1a, E1b, E1c) may be an anode, which is a hole injection electrode, and the second electrode (E2) may be a cathode, which is an electron injection electrode. However, the embodiment is not necessarily limited thereto, and depending on the driving method of the display device, the first electrode (E1a, E1b, E1c) may become a cathode, and the second electrode (E2) may become an anode.

[0098] A capping layer (CPL) may be positioned on the second electrode (E2). The capping layer (CPL) may be positioned continuously across the blue light-emitting region (BLA), the red light-emitting region (RLA), the green light-emitting region (GLA), and the non-emitting region (NLA).

[0099] In the blue light emitting region (BLA), a first passivation layer (PTL1) may be positioned between the second electrode (E2) and the capping layer (CPL). The first passivation layer (PTL1) may include an inorganic material, and for example, may include at least one of silicon nitride, silicon nitride, and silicon oxide. However, the present invention is not limited thereto, and the first passivation layer (PTL1) may also include a high-transmittance material with a high film density, such as a metal or an organic metal material. The first passivation layer (PTL1) may protect the first light-emitting layer (EML1) in an acid treatment process to be described later and may improve the reliability of the display device.

[0100] The first protective layer (PTL1) may be formed through a patterning process or an inkjet process. The first protective layer (PTL1) may be positioned within the first opening (OP1) included in the partition wall (PDL). Alternatively, the first protective layer (PTL1) may be positioned to overlap at least a portion of the first opening (OP1). Alternatively, the first protective layer (PTL1) may be positioned to overlap at least a portion of the upper surface of the partition wall (PDL).

[0101] The first protective layer (PTL1) may be positioned in the blue light emitting region (BLA) and may not be positioned in the red light emitting region (RLA) and the green light emitting region (GLA). The first protective layer (PTL1) may overlap the first light emitting layer (EML1) and may be spaced apart from the second light emitting layer (EML2) and the third light emitting layer (EML3). The first protective layer (PTL1) may overlap the first light emitting element (ED1) and may be spaced apart from the second light emitting element (ED2) and the third light emitting element (ED3).

[0102] A blue color filter (BCF) may be positioned on the first protective layer (PTL1). The blue color filter (BCF) may be formed through an inkjet process and a low-temperature curing process. The blue color filter (BCF) may overlap the first light-emitting layer (EML1) and be spaced apart from the second light-emitting layer (EML2) and the third light-emitting layer (EML3). The blue color filter (BCF) may overlap the first light-emitting element (ED1) and be spaced apart from the second light-emitting element (ED2) and the third light-emitting element (ED3). The blue color filter (BCF) may protect the first light-emitting layer (EML1), reduce diffuse reflection of blue light, and provide blue light with improved color purity.

[0103] The blue color filter (BCF) can be in contact with the capping layer (CPL), and the first protective layer (PTL1) can be in contact with the second electrode (E2).

[0104] An encapsulating layer (ENC) is positioned on the capping layer (CPL). The encapsulating layer (ENC) can seal the display layer by covering not only the upper surface but also the side surfaces of the display layer including the light-emitting elements (ED1, ED2, ED3).

[0105] Since light-emitting elements are highly susceptible to moisture and oxygen, an encapsulating layer (ENC) seals the display layer to block the inflow of external moisture and oxygen. The encapsulating layer (ENC) may include multiple layers, and may be formed as a composite film including both an inorganic film and an organic film, or may be formed as a triple layer in which a first inorganic film, an organic film, and a second inorganic film are formed sequentially.

[0106] Referring to FIG. 1 and FIG. 2 discussed above, a manufacturing process of a display device according to one embodiment will be briefly reviewed.

[0107] First, a plurality of transistors are formed on a substrate (SUB), and a barrier rib (PDL) having openings (OP1, OP2, OP3) is formed on a protective film (IL2). A first ink for forming a hole injection layer (HIL1, HIL2, HIL3) is ejected into each of the openings (OP1, OP2, OP3) of the barrier rib (PDL) (S1). Then, the ejected first ink is dried (S2) and baked (S3) to form the hole injection layers (HIL1, HIL2, HIL3). Although the present specification describes the first ink for convenience, each of the hole injection layers (HIL1, HIL2, HIL3) may include the same hole injection material or different hole injection materials.

[0108] Second ink is ejected (S4) to form hole transport layers (HTL1, HTL2, HTL3) on the next hole injection layers (HIL1, HIL2, HIL3). Then, the ejected second ink is dried (S5) and baked (S6) to form hole transport layers (HTL1, HTL2, HTL3). Although the present specification describes the second ink for convenience, each of the hole transport layers (HTL1, HTL2, HTL3) may include the same hole transport material or different hole transport materials.

[0109] Third ink is ejected (S7) to form light-emitting layers (EML1, EML2, EML3) on the next hole transport layers (HTL1, HTL2, HTL3). Then, the third ink is dried (S8) and baked (S9) to form light-emitting layers (EML1, EML2, EML3). Although the present specification describes the third ink for convenience, each of the light-emitting layers (EML1, EML2, EML3) may include different materials as described above.

[0110] Then, the fourth ink is ejected (S10) to form electron transport layers (ETL1, ETL2, ETL3) on the light-emitting layers (EML1, EML2, EML3). The fourth ink is dried (S11) and baked (S12) to form electron transport layers (ETL1, ETL2, ETL3). Although the fourth ink is described in this specification for convenience, the electron transport layers (ETL1, ETL2, ETL3) may include different materials as described above. The second electron transport layer (ETL2) and the third electron transport layer (ETL3) may include ZnMgO, and the first electron transport layer (ETL1) may include a different material.

[0111] Afterwards, a second electrode (E2) is formed on the electron transport layers (ETL1, ETL2, ETL3) through a deposition process (S13). Then, a first protective layer (PTL1) is formed on the second electrode (E2) overlapping the blue light emitting area (BLA) through a deposition process (S14). Afterwards, ink for manufacturing a blue color filter is printed on the first protective layer (PTL1) (S15), dried (S16), and baked (S17) to provide a blue color filter (BCF).

[0112] Then, an acid treatment process is performed on the substrate (SUB) (S18). The acid treatment process according to one embodiment can be performed in the chamber illustrated in FIG. 3.

[0113] Looking at the chamber (CH) illustrated in Fig. 3, entry and exit of the laminated structure (SUB1) may be possible through the shutter (ST). The laminated structure (SUB1) refers to a structure in which all components except the capping layer (CPL) in Fig. 1 are laminated, as described with reference to Figs. 1 and 2. The chamber (CH) may be made of SUS or a fluorine-based plastic material that can withstand acid corrosion.

[0114] The laminated structure (SUB1) can be loaded into the chamber (CH) through an open shutter (ST). The laminated structure (SUB1) can be supported by a pin (PIN) within the chamber (CH). The height of the laminated structure (SUB1) can be adjusted using the pin (PIN).

[0115] An acid generator (GNT) that maintains a constant acid concentration may be positioned within the chamber (CH). The laminated structure (SUB1) may be placed within the aforementioned chamber (CH) for 10 to 20 minutes. When exposed to an acidic atmosphere, the surface of the ZnMgO included in the second electron transport layer and the third electron transport layer may be modified. That is, the fumed acid may flow into the second and third electron transport layers to repair defects in the ZnMgO and modify the surface of the ZnMgO to improve characteristics. When the defects in the ZnMgO are repaired, the electron transfer efficiency may be improved, and thus the luminous efficiency of the light-emitting device may be increased.

[0116] In addition, in this acid treatment process, the first electron transport layer and the first light-emitting layer that do not contain ZnMgO may be damaged by the acid. The damaged first light-emitting layer may cause problems such as a decrease in the efficiency of the blue light-emitting element and a shortened lifespan of the element. However, the first protective layer (PTL1) and the blue color filter (BCF) according to one embodiment prevent the inflow of acid, thereby preventing damage to the first light-emitting element and increasing its reliability.

[0117] Hereinafter, a display device according to another embodiment will be described with reference to FIGS. 4 to 9. FIGS. 4 and 5 are cross-sectional views of a display device according to another embodiment, FIG. 6 is a cross-sectional view of a display device according to another embodiment, FIG. 7 is a flowchart for a method of manufacturing some components of the display device according to the embodiment of FIG. 6, and FIGS. 8 and 9 are cross-sectional views of a display device according to another embodiment. Descriptions of components identical to those described above will be omitted.

[0118] Referring to FIG. 4, in a display device according to one embodiment, a first light-emitting element (ED1) may overlap a blue light-emitting area (BLA), a second light-emitting element (ED2) may overlap a red light-emitting area (RLA), and a third light-emitting element (ED3) may overlap a green light-emitting area (GLA). The stacked structure of the second light-emitting element (ED2) and the third light-emitting element (ED3) may be the same as the embodiment of FIG. 1.

[0119] The first light-emitting element (ED1) includes a first electrode (E1a), a first hole injection layer (HIL1), a first hole transport layer (HTL1), a first light-emitting layer (EML1), a first electron transport layer (ETL1), and a second electrode (E2).

[0120] Referring to Fig. 4, a first protective layer (PTL1) and a blue color filter (BCF) may be positioned between a first electron transport layer (ETL1) and a second electrode (E2). A capping layer (CPL) may be positioned on the second electrode (E2). The capping layer (CPL) may be positioned continuously across a blue light emitting region (BLA), a red light emitting region (RLA), a green light emitting region (GLA), and a non-emitting region (NLA).

[0121] The first protective layer (PTL1) may include an inorganic material, for example, at least one of silicon nitride, silicon nitride, and silicon oxide. The first protective layer (PTL1) protects the first light-emitting layer (EML1) during the acid treatment process described below, and may improve the reliability of the display device.

[0122] The first protective layer (PTL1) can be formed through a patterning process or an inkjet process. The first protective layer (PTL1) can be positioned within the first opening (OP1) included in the partition wall (PDL). A blue color filter (BCF) can be positioned on the first protective layer (PTL1). The blue color filter (BCF) can be formed through an inkjet process or a low-temperature curing process. The blue color filter (BCF) can protect the first light-emitting layer (EML1), reduce diffuse reflection of blue light, and provide blue light with improved color purity.

[0123] The blue color filter (BCF) can be in contact with the second electrode (E2), and the first protective layer (PTL1) can be in contact with the first electron transport layer (ETL1).

[0124] Referring to FIG. 5 below, a display device according to one embodiment may include a blue color filter (BCF) and a first passivation layer (PTL1) positioned on a second electrode (E2). The blue color filter (BCF) may be in contact with the second electrode (E2), and the first passivation layer (PTL1) may be in contact with a capping layer (CPL).

[0125] Referring to FIG. 6 below, in a display device according to one embodiment, a first light-emitting element (ED1) may overlap a blue light-emitting area (BLA), a second light-emitting element (ED2) may overlap a red light-emitting area (RLA), and a third light-emitting element (ED3) may overlap a green light-emitting area (GLA). The stacked structure of the second light-emitting element (ED2) and the third light-emitting element (ED3) may be the same as the embodiment of FIG. 1.

[0126] The first light-emitting element (ED1) includes a first electrode (E1a), a first hole injection layer (HIL1), a first hole transport layer (HTL1), a first light-emitting layer (EML1), a first electron transport layer (ETL1), and a second electrode (E2).

[0127] Referring to Fig. 6, a first protective layer (PTL1) may be positioned on the capping layer (CPL). The capping layer (CPL) may be positioned continuously across the blue light emitting region (BLA), the red light emitting region (RLA), the green light emitting region (GLA), and the non-emitting region (NLA).

[0128] The first protective layer (PTL1) may include an inorganic material, for example, at least one of silicon nitride, silicon nitride, and silicon oxide. The first protective layer (PTL1) protects the first light-emitting element (ED1), particularly the first light-emitting layer (EML1), during an acid treatment process described below, and may improve the reliability of the display device.

[0129] The first protective layer (PTL1) may be formed through a patterning process or an inkjet process. The first protective layer (PTL1) may be positioned on the barrier rib (PDL). The first protective layer (PTL1) may be formed along a step of the capping layer (CPL). The first protective layer (PTL1) may be positioned to overlap at least a portion of the first opening (OP1). The first protective layer (PTL1) may be positioned to overlap at least a portion of the barrier rib (PDL).

[0130] The first protective layer (PTL1) may be positioned in the blue light emitting region (BLA) and may not be positioned in the red light emitting region (RLA) and the green light emitting region (GLA). The first protective layer (PTL1) may overlap the first light emitting layer (EML1) and may be spaced apart from the second light emitting layer (EML2) and the third light emitting layer (EML3). The first protective layer (PTL1) may overlap the first light emitting element (ED1) and may be spaced apart from the second light emitting element (ED2) and the third light emitting element (ED3).

[0131] Referring to FIG. 6 and FIG. 7 discussed above, a manufacturing process of a display device according to one embodiment will be briefly reviewed.

[0132] First, a plurality of transistors are formed on a substrate (SUB), and a barrier rib (PDL) having openings (OP1, OP2, OP3) is formed on a protective film (IL2). A first ink for forming a hole injection layer (HIL1, HIL2, HIL3) is ejected into each of the openings (OP1, OP2, OP3) of the barrier rib (PDL) (S1). Then, the ejected first ink is dried (S2) and baked (S3) to form the hole injection layers (HIL1, HIL2, HIL3). Although the present specification describes the first ink for convenience, each of the hole injection layers (HIL1, HIL2, HIL3) may include the same hole injection material or different hole injection materials.

[0133] Second ink is ejected (S4) to form hole transport layers (HTL1, HTL2, HTL3) on the next hole injection layers (HIL1, HIL2, HIL3). Then, the ejected second ink is dried (S5) and baked (S6) to form hole transport layers (HTL1, HTL2, HTL3). Although the present specification describes the second ink for convenience, each of the hole transport layers (HTL1, HTL2, HTL3) may include the same hole transport material or different hole transport materials.

[0134] The third ink is ejected (S7_) to form the light-emitting layers (EML1, EML2, EML3) on the next hole transport layers (HTL1, HTL2, HTL3). Then, the third ink is dried (S8) and baked (S9) to form the light-emitting layers (EML1, EML2, EML3). Although the present specification describes the third ink for convenience, each of the light-emitting layers (EML1, EML2, EML3) may include different materials as described above.

[0135] Then, the fourth ink for forming electron transport layers (ETL1, ETL2, ETL3) is ejected on the light-emitting layers (EML1, EML2, EML3) (S10). The fourth ink is dried (S11) and baked (S12) to form electron transport layers (ETL1, ETL2, ETL3). Although the fourth ink is described in this specification for convenience, the electron transport layers (ETL1, ETL2, ETL3) may include different materials as described above. The second electron transport layer (ETL2) and the third electron transport layer (ETL3) may include ZnMgO, and the first electron transport layer (ETL1) may include a different electron transport material.

[0136] Afterwards, a second electrode (E2) and a capping layer (CPL) are sequentially formed on the electron transport layers (ETL1, ETL2, ETL3) through a deposition process (S13, S14). Then, a first protective layer (PTL1) is formed on the capping layer (CPL) overlapping the blue light emitting region (BLA) through a deposition process (S15). Afterwards, an acid treatment process is performed on the substrate (SUB) (S16). The acid treatment process according to one embodiment can be performed in the chamber illustrated in FIG. 3.

[0137] Referring to the following FIG. 8, a display device according to another embodiment will be described. In the display device according to the embodiment of FIG. 8, the first light-emitting element (ED1) may overlap with the blue light-emitting area (BLA), the second light-emitting element (ED2) may overlap with the red light-emitting area (RLA), and the third light-emitting element (ED3) may overlap with the green light-emitting area (GLA). The stacking structure of the second light-emitting element (ED2) and the third light-emitting element (ED3) may be the same as the embodiment of FIG. 6.

[0138] A first passivation layer (PTL1) may be positioned on the second electrode (E2) in the blue light emitting region (BLA). A capping layer (CPL) may be positioned on the first passivation layer (PTL1). The second electrode (E2) and the capping layer (CPL) may be positioned continuously across the blue light emitting region (BLA), the red light emitting region (RLA), the green light emitting region (GLA), and the non-emission region (NLA).

[0139] The first protective layer (PTL1) may include an inorganic material, for example, at least one of silicon nitride, silicon nitride, and silicon oxide. The first protective layer (PTL1) protects the first light-emitting element (ED1), particularly the first light-emitting layer (EML1), during an acid treatment process described below, and may improve the reliability of the display device.

[0140] The first protective layer (PTL1) may be positioned in the blue light emitting region (BLA) and may not be positioned in the red light emitting region (RLA) and the green light emitting region (GLA). The first protective layer (PTL1) may overlap the first light emitting layer (EML1) and may be spaced apart from the second light emitting layer (EML2) and the third light emitting layer (EML3). The first protective layer (PTL1) may overlap the first light emitting element (ED1) and may be spaced apart from the second light emitting element (ED2) and the third light emitting element (ED3).

[0141] Referring to FIG. 9 below, a first protective layer (PTL1) according to one embodiment may be positioned between a first electron transport layer (ETL1) and a second electrode (E2). The first protective layer (PTL1) may be in contact with the first electron transport layer (ETL1) and the second electrode (E2). Except for the position of the first protective layer (PTL1), the embodiment may be the same as that of FIG. 6.

[0142] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. A substrate including a red light emitting region, a green light emitting region, and a blue light emitting region, A transistor positioned on the above substrate, A first light-emitting element electrically connected to the transistor and overlapping the blue light emitting region, and A capping layer positioned on the first light-emitting element is included, The above first light-emitting element, First electrode, A first light-emitting layer positioned on the first electrode, A first electron transport layer positioned on the first light-emitting layer, and A second electrode positioned on the first electron transport layer is included, A first protective layer is positioned between the second electrode and the capping layer, between the second electrode and the first electron transport layer, and on any one of the upper surfaces of the capping layer. The first protective layer is a display device spaced apart from the red light emitting area and the green light emitting area.

2. In paragraph 1, A display device in which the first protective layer is positioned between the second electrode and the capping layer.

3. In paragraph 2, A display device further comprising a blue color filter positioned between the first protective layer and the capping layer.

4. In paragraph 1, A display device in which the first protective layer is positioned between the first electron transport layer and the second electrode.

5. In paragraph 4, A display device further comprising a blue color filter positioned between the first protective layer and the second electrode.

6. In paragraph 1, a second light-emitting element overlapping the red light-emitting region, and A display device further comprising a third light-emitting element overlapping the green light-emitting region.

7. In paragraph 6, The above second light emitting element, a second light-emitting layer comprising a first quantum dot; A second electron transport layer positioned on the second light-emitting layer, and A display device comprising a second electrode positioned on the second electron transport layer.

8. In paragraph 7, A display device wherein the second electron transport layer comprises ZnMgO.

9. In paragraph 7, The third light-emitting element is, a third light-emitting layer including a second quantum dot, a third electron transport layer positioned on the third light-emitting layer, and A display device comprising a second electrode positioned on the third electron transport layer.

10. In paragraph 9, A display device in which the third electron transport layer comprises ZnMgO.

11. In paragraph 1, A display device wherein the first protective layer comprises at least one of silicon nitride, silicon nitride, and silicon oxide.

12. In paragraph 1, A display device wherein the first light-emitting layer comprises an organic material.

13. In paragraph 9, A display device wherein the second electron transport layer and the third electron transport layer comprise the same material.

14. In paragraph 13, A display device wherein the first electron transport layer comprises a different material from the second electron transport layer.

15. In paragraph 13, A display device in which the first electron transport layer, the second electron transport layer, and the third electron transport layer are spaced apart from each other with a partition wall therebetween.

16. In paragraph 13, The first light-emitting element includes a first hole injection layer and a first hole transport layer, The second light-emitting element includes a second hole injection layer and a second hole transport layer, The third light-emitting element includes a third hole injection layer and a third hole transport layer, The first hole injection layer, the second hole injection layer, and the third hole injection layer are spaced apart from each other, A display device in which the first hole transport layer, the second hole transport layer, and the third hole transport layer are spaced apart from each other.

17. A substrate including a red light emitting region, a green light emitting region, and a blue light emitting region, A plurality of transistors positioned on the substrate, First light-emitting elements, second light-emitting elements, and third light-emitting elements, each electrically connected to the plurality of transistors, which emit light of different colors; A capping layer positioned on the first light-emitting element, the second light-emitting element, and the third light-emitting element, and A first protective layer positioned between the first light-emitting element and the capping layer is included, The above first light-emitting element, First electrode, A first light-emitting layer positioned on the first electrode, A first electron transport layer positioned on the first light-emitting layer, and A second electrode positioned on the first electron transport layer is included, A display device in which the second light-emitting element includes a second light-emitting layer, the third light-emitting element includes a third light-emitting layer, and the first protective layer is spaced apart from the second light-emitting layer and the third light-emitting layer along the thickness direction of the substrate.

18. In paragraph 17, The display device further includes a partition wall positioned between the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer, A display device in which the second electrode and the capping layer are continuously positioned across the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer.

19. In paragraph 18, The second light-emitting element further includes a second electron transport layer positioned on the second light-emitting layer, The third light-emitting element further includes a third electron transport layer positioned on the third light-emitting layer, The first electron transport layer, the second electron transport layer, and the third electron transport layer are spaced apart from each other with the above-mentioned barrier layer in between, The second electron transport layer and the third electron transport layer comprise the same material, A display device wherein the second electron transport layer and the first electron transport layer comprise different materials.

20. In paragraph 17, A display device further comprising a blue color filter in contact with the first protective layer.

21. In paragraph 20, The blue color filter is positioned on the second electrode, The first protective layer is positioned on the blue color filter, A display device in which the capping layer is positioned on the first protective layer.

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