Light-emitting device, display panel, and display device

Abstract

A light-emitting device. The light-emitting device comprises: an anode, a cathode, a quantum dot light-emitting layer located between the anode and the cathode, and a hole transport layer located between the anode and the quantum dot light-emitting layer, wherein a material of the hole transport layer includes P-type amorphous silicon.

Description

Light-emitting devices, display panels and display devices Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a light-emitting device, a display panel, and a display apparatus. Background Technology

[0002] Quantum dot light-emitting diodes (QLEDs) have gained widespread attention in the display field due to their advantages such as high color gamut, self-emission, low start-up voltage, and fast response speed. The working principle of a quantum dot light-emitting diode is as follows: electrons and holes are injected into both sides of the quantum dot light-emitting layer. These electrons and holes recombine in the quantum dot light-emitting layer to form photons, which ultimately emit light. Summary of the Invention

[0003] On one hand, a light-emitting device is provided, comprising: an anode, a cathode, a quantum dot light-emitting layer located between the anode and the cathode, and a hole transport layer located between the anode and the quantum dot light-emitting layer; wherein the material of the hole transport layer comprises: p-type amorphous silicon.

[0004] In some embodiments, the light-emitting device further includes an electron blocking layer located between the hole transport layer and the quantum dot light-emitting layer, wherein the electron blocking layer is made of at least one of an insulating material and a p-type semiconductor material.

[0005] In some embodiments, the conduction band of the electron blocking layer material is greater than or equal to -3.0 eV, the valence band of the electron blocking layer material is less than or equal to -5 eV, and the band gap of the electron blocking layer material is greater than or equal to 3 eV.

[0006] In some embodiments, the electron blocking layer is made of at least one of the following: aluminum oxide, hafnium dioxide, polymethyl methacrylate, polystyrene, polyethylene terephthalate, cuprous thiocyanate, nickel oxide, tungsten trioxide, copper oxide, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)], and polyvinylcarbazole.

[0007] In some embodiments, the electron blocking layer is made of an insulating material, and the thickness of the electron blocking layer ranges from 1 nm to 30 nm.

[0008] In some embodiments, the electron blocking layer is made of a P-type semiconductor material, and the thickness of the electron blocking layer ranges from 1 nm to 100 nm.

[0009] In some embodiments, the light-emitting device further includes: a negatively charged interface layer located between the hole transport layer and the quantum dot light-emitting layer; the material of the negatively charged interface layer includes: alkali metal cations, and anions having organic groups and acid radicals; wherein the number of negative charges in the negatively charged interface layer is greater than the number of positive charges.

[0010] In some embodiments, the material of the negatively charged interface layer includes at least one of the following: sodium 1,4-phenylbisphosphonate, sodium poly(vinylphosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalene disulfonate, sodium 1,3-propanedisulfonate, sodium isophenyltrimethylolpropane, sodium citrate, and sodium polyacrylate.

[0011] In some embodiments, in the negatively charged interface layer, the ratio of the number of atoms of the anion to the charge of the anion ranges from 4 to 30.

[0012] In some embodiments, the thickness of the negatively charged interface layer ranges from 0.1 nm to 20 nm.

[0013] In some embodiments, the light-emitting device includes an electron blocking layer, and the negatively charged interface layer is located on the side of the electron blocking layer away from the anode.

[0014] In some embodiments, the light-emitting device further includes an auxiliary layer located between the hole transport layer and the quantum dot light-emitting layer, the auxiliary layer comprising: a first type of material and a second type of material; the first type of material comprises: an organic insulating material; the second type of material comprises: an alkali metal cation and an anion having organic groups and acid radicals.

[0015] In some embodiments, the first type of material includes at least one of polymethyl methacrylate, polystyrene, and polyethylene terephthalate; the second type of material includes at least one of sodium 1,4-benzenediphosphonate, sodium poly(vinylphosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalenedisulfonate, sodium 1,3-propanedisulfonate, sodium isophthalate, sodium citrate, and sodium polyacrylate.

[0016] In some embodiments, in the auxiliary layer, the ratio of the mass of the first type of material to the mass of the second type of material ranges from 0.25 to 0.75.

[0017] In some embodiments, the thickness of the auxiliary layer ranges from 1 nm to 30 nm.

[0018] In some embodiments, the P-type doping material in the P-type amorphous silicon includes at least one of trimethylborane, borane, and boron trichloride.

[0019] In some embodiments, in the p-type amorphous silicon, the doping concentration of the p-type doped material ranges from 10. 17 / cm 3 ~10 20 / cm 3 .

[0020] In some embodiments, the thickness of the hole transport layer ranges from 5 nm to 100 nm.

[0021] In some embodiments, the Fermi level of the hole transport layer ranges from -4.5 eV to -5.8 eV.

[0022] In some embodiments, the material of the portion of the hole transport layer away from the anode further includes a regulating element, which includes at least one of oxygen, nitrogen, and carbon.

[0023] In some embodiments, in the portion of the hole transport layer that includes the modulating element, the ratio of the number of atoms of the modulating element to the number of atoms of silicon is less than or equal to 67 / 33.

[0024] In some embodiments, the thickness of the portion of the hole transport layer including the adjustment element is in the range of 0.01 to 0.3 as a ratio to the thickness of the hole transport layer.

[0025] On the other hand, a display panel is provided, the display panel including: a pixel defining layer and a plurality of light-emitting devices, the pixel defining layer having a plurality of openings; the plurality of light-emitting devices being disposed one-to-one in the plurality of openings; at least one of the plurality of light-emitting devices being a light-emitting device as described in any of the above embodiments.

[0026] In another aspect, a display device is provided. The display device includes: a display panel as described in any of the above embodiments and a driver chip, wherein the driver chip is used to drive the display panel to perform a display. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. Furthermore, the drawings described below can be considered as schematic diagrams and are not intended to limit the actual dimensions, etc., of the products involved in the embodiments of this disclosure.

[0028] Figure 1 is a structural diagram of a display device according to some embodiments of the present disclosure;

[0029] Figure 2 is a structural diagram of a display panel according to some embodiments of the present disclosure;

[0030] Figure 3 is a structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0031] Figure 4 is a graph showing the decrease in brightness of a light-emitting device over time according to some embodiments of the present disclosure;

[0032] Figure 5 is an energy level diagram of a light-emitting device according to some embodiments of the present disclosure;

[0033] Figure 6 is another structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0034] Figure 7 is another energy level diagram of a light-emitting device according to some embodiments of the present disclosure;

[0035] Figure 8 is a graph showing the relationship between current density and voltage of a light-emitting device according to some embodiments of the present disclosure;

[0036] Figure 9 is another structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0037] Figure 10 is a fluorescence spectrum of a light-emitting device according to some embodiments of the present disclosure;

[0038] Figure 11 is another structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0039] Figure 12 is another fluorescence spectrum of a light-emitting device according to some embodiments of the present disclosure;

[0040] Figure 13 is another structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0041] Figure 14 is another structural diagram of a light-emitting device according to some embodiments of the present disclosure. Detailed Implementation

[0042] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0043] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0044] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0045] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0046] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0047] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0048] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0049] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0050] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0051] Some embodiments of this disclosure provide a display device 1000, which can be any device that displays text or images, whether moving (e.g., video) or stationary (e.g., still images). More specifically, the embodiments are contemplated to be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones (e.g., cell phones), wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc. Figure 1 illustrates a mobile phone as an example of the display device 1000.

[0052] For example, the display device 1000 can be an electroluminescent display device or a photoluminescent display device. When the display device 1000 is an electroluminescent display device, it can be an organic light-emitting diode (OLED) or a quantum dot light-emitting diode (QLED). When the display device 1000 is a photoluminescent display device, it can be a quantum dot photoluminescent display device. The following uses a QLED display device as an example to illustrate some embodiments of this disclosure; however, the implementation of this disclosure includes, but is not limited to, these embodiments, and any other display device can be considered as long as the same technical concept is applied.

[0053] Please refer to Figure 1. The above-mentioned display device 1000 includes: a display panel 100 and a driver chip. The driver chip is used to drive the display panel 100 to perform display.

[0054] In some embodiments, as shown in FIG2, the display panel 100 includes a substrate 20 and a pixel defining layer 30 located on one side of the substrate 20, wherein a plurality of openings Q are formed on the pixel defining layer 30. The display panel 100 also includes a plurality of light-emitting devices 10, wherein the plurality of light-emitting devices 10 are disposed one-to-one in the plurality of openings Q.

[0055] For example, the plurality of light-emitting devices 10 include: a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103. The first light-emitting device 101 is configured to emit one of red light, blue light and green light, the second light-emitting device 102 is configured to emit another of red light, blue light and green light, and the third light-emitting device 103 is configured to emit the last of red light, blue light and green light, so as to realize full-color display of display panel 100.

[0056] The structure of the light-emitting device 10 is described below by way of example.

[0057] In some embodiments, as shown in FIG3, the light-emitting device 10 includes: an anode 11, a quantum dot light-emitting layer 13 and a cathode 12 stacked together, a hole transport layer 14 is further disposed between the anode 11 and the quantum dot light-emitting layer 13, and an electron transport layer 15 is further disposed between the cathode 12 and the quantum dot light-emitting layer 13.

[0058] For example, the material of the quantum dot light-emitting layer 13 may include group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. For instance, the group II-VI semiconductor compound may be selected from: binary semiconductor compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or mixtures thereof; ternary semiconductor compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, C dZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary semiconductor compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto. For example, the III-V semiconductor compound may be selected from: binary semiconductor compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary semiconductor compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary semiconductor compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but not limited thereto. For example, the IV-VI group semiconductor compound may be selected from: binary semiconductor compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary semiconductor compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary semiconductor compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but is not limited thereto.The group IV semiconductors may be selected, for example, from: elemental (monological) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. The group I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but are not limited thereto. The group I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS, or mixtures thereof, but are not limited thereto. The group II-III-V semiconductor compounds may include, for example, InZnP, but are not limited thereto.

[0059] The light-emitting principle of the light-emitting device 10 is as follows: through the circuit connected by the anode 11 and the cathode 12, holes are injected into the quantum dot light-emitting layer 13 by the anode 11 and electrons are injected into the quantum dot light-emitting layer 13 by the cathode 12. The injected electrons and holes form excitons (i.e. electron-hole pairs) in the quantum dot light-emitting layer 13. The excitons return to the ground state through radiative transition and emit photons.

[0060] For example, in order to ensure that the light-emitting device 10 can emit light effectively, the anode 11 can be made of a material with a high work function. In this way, the holes generated by the anode 11 can be effectively migrated to the quantum dot light-emitting layer 13 under the drive of the electric field, and then recombine with the electrons generated by the cathode 12 to emit light.

[0061] In some examples, the anode 11 can be a transparent electrode. In this case, the material of the anode 11 can be indium tin oxide (ITO) or fluorine-doped tin dioxide conductive glass (FTO), etc. Alternatively, the material of the anode 11 can also be a conductive polymer, such as polyaniline, polycarbazole, polythiophene, or polypropylene. In still other examples, the anode 11 can be an opaque electrode. In this case, the material of the anode 11 can be a metallic material, such as aluminum or silver.

[0062] For example, the cathode 12 can be made of a material with a low work function, which makes it easier for electrons from the cathode 12 to be injected into the electron transport layer 15. In this way, the electrons generated by the cathode 12 can be effectively migrated to the quantum dot light-emitting layer 13 under the drive of the electric field, and then recombine with the holes generated by the anode 11 to emit light.

[0063] In some examples, the cathode 12 can be made of a metallic material, a metal oxide, or a metal alloy. Examples of metallic materials include aluminum, silver, gold, magnesium, calcium, ytterbium, indium, lithium, potassium, sodium, tin, titanium, lead, samarium, or yttrium. Examples of metal oxides include indium tin oxide or indium zinc oxide. Examples of metal alloys include magnesium-silver alloys, ytterbium-gold alloys, ytterbium-silver alloys, lithium-aluminum alloys, or lithium-calcium-magnesium alloys. Alternatively, the cathode 12 can be made of a multilayer material, such as magnesium / aluminum, magnesium / silver, aluminum / silver, aluminum / gold, ytterbium / gold, ytterbium / silver, calcium / magnesium, calcium / silver, or barium / silver.

[0064] In some embodiments, as shown in FIG3, to improve luminous efficiency, the light-emitting device 10 further includes a hole injection layer (not shown in the figure), which is located on the side of the hole transport layer 14 away from the quantum dot light-emitting layer 13. The light-emitting device 10 also includes an electron blocking layer 16 (refer to FIG6), which is located on the side of the hole transport layer 14 closer to the quantum dot light-emitting layer 13.

[0065] In some embodiments, as shown in FIG3, to improve luminous efficiency, the light-emitting device 10 further includes at least one of an electron injection layer (not shown) and a hole blocking layer (not shown). The electron injection layer is located on the side of the electron transport layer 15 away from the quantum dot light-emitting layer 13, and the hole blocking layer is located on the side of the electron transport layer 15 closer to the quantum dot light-emitting layer 13.

[0066] By setting up a hole injection layer, a hole transport layer 14, and an electron blocking layer 16, a transition step is set between the anode 11 and the quantum dot light-emitting layer 13. By setting up an electron injection layer, an electron transport layer 15, and a hole blocking layer, a transition step is set between the cathode 12 and the quantum dot light-emitting layer 13. This reduces the potential barrier height that carrier transitions need to overcome, resulting in higher luminous efficiency of the light-emitting device 10.

[0067] In some embodiments, as shown in FIG3, the inventors have found that there is a significant difference in service life between using ZnO-type inorganic materials as electron transport layer 15 and organic materials as hole transport layer 14.

[0068] For example, the photoluminescence quantum dot yield (PLQY) of the light-emitting device 10 after T80 aging can still be maintained at more than 95% of the original yield. At the same time, the light-emitting device 10 after aging will show an abnormal fluorescence peak in the 470 nm to 520 nm wavelength range. This fluorescence peak is caused by the degradation of the hole transport layer 14 material poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (abbreviated as TFB).

[0069] Therefore, quantum dots, as the material of the quantum dot light-emitting layer 13, have good stability. The decay of the lifetime of the light-emitting device 10 is mainly due to carrier imbalance, charge accumulation, and the damage to the organic hole material caused by these factors.

[0070] Based on this, as shown in Figure 3, an embodiment of this disclosure provides a light-emitting device 10, wherein the hole transport layer 14 is made of P-type amorphous silicon.

[0071] For example, P-type amorphous silicon is amorphous silicon doped with a P-type doping material, wherein the P-type doping material in the P-type amorphous silicon includes at least one of trimethylborane, borane, and boron trichloride.

[0072] Among them, p-type amorphous silicon has a high work function of 5.5 eV and a deep valence band position of -5.6 V, which can well match the band structure of the light-emitting device 10. Meanwhile, the hole mobility of p-type amorphous silicon is approximately 0.1 cm⁻¹. 2 / Vs, the hole mobility of organic materials ranges from approximately 10. -4 cm 2 / Vs~10 -3 cm 2 / Vs, the hole mobility of p-type amorphous silicon is much higher than that of organic materials. Therefore, p-type amorphous silicon has a suitable valence band depth and excellent hole mobility, making it a potential material for hole transport layer 14.

[0073] In some embodiments, as shown in FIG3, the method for fabricating the light-emitting device 10 includes the following steps.

[0074] A p-type amorphous silicon thin film is formed as a hole transport layer 14 on a patterned ITO glass using plasma-enhanced chemical vapor deposition. A quantum dot emitting layer 13 is formed on the hole transport layer 14 by spin-coating a quantum dot dispersion. The concentration of the quantum dot dispersion used ranges from 5 mg / mL to 200 mg / mL, and the thickness of the quantum dot emitting layer 13 ranges from 5 nm to 200 nm.

[0075] An electron transport layer 15 is formed on the quantum dot light-emitting layer 13 by spin-coating a nanocrystalline dispersion. The selected material is one or more of ZnO or ZnMgO, and the concentration of the nanocrystalline dispersion ranges from 5 mg / mL to 200 mg / mL. The thickness of the electron transport layer 15 ranges from 5 nm to 200 nm. A cathode 12 is fabricated on the electron transport layer 15 by vapor deposition. The material used can be one or more of Al, Ag, and Cu, and the thickness of the cathode 12 ranges from 20 nm to 1000 nm. Then, the light-emitting device 10 is encapsulated in a nitrogen atmosphere to obtain the light-emitting device 10.

[0076] Figure 4 is a graph showing the decrease in brightness of the light-emitting device 10 over time according to some embodiments of the present disclosure. The horizontal axis represents time in hours, and the vertical axis represents luminous intensity in au (au is short for arbitrary units). The structure of the light-emitting device 10 can be seen in Figure 3.

[0077] The light-emitting device 10 of Comparative Example 1 includes: an anode 11, a hole injection layer, a hole transport layer 14, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12 stacked together. The anode 11 is made of ITO, the hole injection layer is made of polyethylene dioxythiophene-polystyrene sulfonate (PEDOT:PSS) with a thickness of 50 nm, the hole transport layer 14 is made of TFB with a thickness d1 of 30 nm, the quantum dot light-emitting layer 13 has a thickness of 20 nm, the electron transport layer 15 is made of ZnMgO with a thickness of 50 nm, and the cathode 12 is made of Al.

[0078] The light-emitting device 10 of Example 1 includes: an anode 11, a hole transport layer 14, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12 stacked together. The anode 11 is made of ITO, the hole transport layer 14 is made of p-type amorphous silicon with a thickness d1 of 30 nm, the quantum dot light-emitting layer 13 has a thickness of 20 nm, the electron transport layer 15 is made of ZnMgO with a thickness of 50 nm, and the cathode 12 is made of Al.

[0079] As shown in Figure 4, under the 100 nits aging test condition, after 100 hours, the brightness decay rate of the light-emitting device 10 in Comparative Example 1 was approximately 20%. In Example 1, after 140 hours, the brightness decay rate of the light-emitting device 10 in Example 1 was less than 5%. Therefore, the lifetime of the light-emitting device 10 in Example 1 is greater than that of the light-emitting device 10 in Comparative Example 1. This is because, compared to the use of organic materials in the hole transport layer 14, the material of the hole transport layer 14 includes P-type amorphous silicon, which effectively solves the problem of performance degradation of the light-emitting device 10 caused by the degradation of organic materials.

[0080] In some embodiments, the doping concentration of the P-type doped material in P-type amorphous silicon ranges from 10. 17 / cm 3 ~10 20 / cm 3 .

[0081] For example, in p-type amorphous silicon, the doping concentration of the p-type doped material is 10. 17 / cm 3 10 18 / cm3 10 19 / cm 3 Or 10 20 / cm 3 There are no restrictions here.

[0082] Increasing the doping concentration of the p-type doped material can lower the Fermi level position of the hole transport layer 14, which is beneficial for hole transport. However, increasing the doping concentration of the p-type doped material will decrease the hole mobility of the hole transport layer 14. Therefore, the doping concentration of the p-type doped material should be in the range of 10. 17 / cm 3 ~10 20 / cm 3 The configuration balances the performance of hole transport. The Fermi level represents the highest energy level an electron can occupy at absolute zero.

[0083] In some embodiments, as shown in FIG3, the thickness d1 of the hole transport layer 14 ranges from 5 nm to 100 nm.

[0084] For example, the thickness d1 of the hole transport layer 14 can be 5nm, 10nm, 15nm, 20nm, 30nm, 35nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, etc., and there is no limitation here.

[0085] Because of the lattice defects in p-type amorphous silicon, a thickness d1 of the hole transport layer 14 that is too large may lead to nonradiative recombination of charge carriers. Therefore, by setting the thickness d1 of the hole transport layer 14 to be in the range of 5nm to 100nm, the hole transport layer 14 can be guaranteed to have good coverage and uniformity, and the problem of nonradiative recombination of charge carriers in the hole transport layer 14 can be effectively avoided.

[0086] In some embodiments, as shown in FIG3, the Fermi level range of the hole transport layer 14 is -4.5eV to -5.8eV.

[0087] For example, the Fermi level of the hole transport layer 14 is -4.5eV, -4.6eV, -4.7eV, -4.8eV, -4.9eV, -5.0eV, -5.1eV, -5.2eV, -5.3eV, -5.4eV, -5.5eV, -5.6eV, -5.7eV, or -5.8eV, etc., and there is no limitation here.

[0088] By setting the Fermi level range of the hole transport layer 14 to -4.5eV to -5.8eV, the amorphous silicon layer can be effectively guaranteed to be p-type, thereby enabling the hole transport layer 14 to have good hole transport capability.

[0089] However, the inventors also discovered that compared to the hole transport layer 14 formed from organic materials, the hole transport layer 14 formed from p-type amorphous silicon has a very high doping concentration and higher conductivity, which can cause carrier quenching on the surface of the hole transport layer 14. Moreover, as shown in FIG5, which is an energy level diagram of the light-emitting device 10 according to some embodiments of the present disclosure, the band gap of p-type amorphous silicon is approximately 1.8 eV to 2 eV. Compared to the hole transport layer 14 formed from organic materials, the LUMO at the conduction band position is lower, making it easier for electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14 to occur, causing carrier quenching at the interface between the hole transport layer 14 and the quantum dot light-emitting layer 13, resulting in a decrease in the efficiency of the light-emitting device 10.

[0090] Based on this, as shown in Figure 6, the light-emitting device 10 further includes an electron blocking layer 16 located between the hole transport layer 14 and the quantum dot light-emitting layer 13. The material of the electron blocking layer 16 includes at least one of an insulating material and a P-type semiconductor material.

[0091] As shown in Figure 7, which is another energy level diagram of a light-emitting device 10 according to some embodiments of the present disclosure, an electron blocking layer 16 comprising at least one of an insulating material and a P-type semiconductor material has a wide bandgap. The electron blocking layer 16 constructs an electron transport barrier, preventing electrons (denoted as e) from passing through it. - The electrons are transferred to the hole transport layer 14 with a small band gap to effectively suppress electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14, alleviate the problem of carrier quenching, and help improve the quantum yield of the light-emitting device 10, thereby improving the performance of the light-emitting device 10 based on the hole transport layer 14 formed by p-type amorphous silicon.

[0092] For example, the electron blocking layer 16 is made of at least one of the following: aluminum oxide, hafnium dioxide, polymethyl methacrylate, polystyrene, polyethylene terephthalate, cuprous thiocyanate, nickel oxide, tungsten trioxide, copper oxide, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)], and polyvinylcarbazole.

[0093] Aluminum oxide and hafnium dioxide are inorganic insulating materials, and, for example, an electron blocking layer 16 is formed by a magnetron sputtering deposition process or a sol-gel-post-annealing method.

[0094] Polymethyl methacrylate, polystyrene, and polyethylene terephthalate are organic insulating materials, and, for example, an electron blocking layer 16 is formed by a solution spin coating process.

[0095] For example, as shown in FIG6, the electron blocking layer 16 is made of an insulating material, and the thickness d2 of the electron blocking layer 16 ranges from 1 nm to 30 nm.

[0096] For example, the thickness d2 of the electron blocking layer 16 can be 1nm, 2nm, 4nm, 6nm, 7nm, 9nm, 10nm, 12nm, 15nm, 20nm, 23nm, 25nm, 28nm or 30nm, etc., and there is no limit here.

[0097] Nickel oxide, tungsten trioxide, and copper oxide are P-type inorganic semiconductor materials. For example, an electron blocking layer 16 is formed by magnetron sputtering, nanocrystalline dispersion spin coating, or solution spin coating.

[0098] Poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] and polyvinylcarbazole are P-type organic semiconductor materials. Exemplarily, an electron blocking layer 16 is formed by a solution spin coating process, wherein the concentration of the spin coating solution ranges from 1 mg / mL to 50 mg / mL.

[0099] For example, as shown in FIG6, the electron blocking layer 16 is made of a P-type semiconductor material, and the thickness d2 of the electron blocking layer 16 ranges from 1 nm to 100 nm.

[0100] For example, the thickness d2 of the electron blocking layer 16 can be 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 70nm, 75nm, 80nm, 90nm, 95nm or 100nm, etc., and there is no limit here.

[0101] When the material of the electron blocking layer 16 includes an insulating material, the electron blocking layer 16 will block both electrons and holes. The degree of blocking is related to the thickness d2 of the electron blocking layer 16. The thickness d2 of the electron blocking layer 16 is set in the range of 1nm to 30nm. Charge carriers can only be transported by tunneling. The electron blocking layer 16 can prevent excess electrons from entering the hole transport layer 14.

[0102] The electron blocking layer 16 is made of P-type semiconductor material. The introduction of P-type semiconductor material can build an electron blocking barrier, effectively suppress electron leakage from quantum dot light-emitting layer 13 to hole transport layer 14, alleviate the problem of carrier quenching, and does not block hole transport.

[0103] In some embodiments, as shown in Figures 6 and 7, the conduction band of the electron blocking layer 16 material is greater than or equal to -3.0 eV, the valence band of the electron blocking layer 16 material is less than or equal to -5 eV, and the band gap of the electron blocking layer 16 material is greater than or equal to 3 eV.

[0104] The valence band and conduction band are two fundamental concepts describing the energy states of electrons in a solid. The valence band is the highest energy band that can be filled by electrons at 0 K, while the conduction band is the energy band above the valence band where electrons can move freely.

[0105] For example, the conduction band of the electron blocking layer 16 material is -3.0eV, -2.5eV, -2eV, -1.8eV, -1.5eV or -1eV, etc., and there is no limitation here.

[0106] For example, the valence band of the electron blocking layer 16 material is -5eV, -5.2eV, -5.5eV, -5.8eV, -6eV, -6.3eV or -6.5eV, etc., and there is no limitation here.

[0107] For example, the band gap of the electron blocking layer 16 material is 3eV, 3.2eV, 3.5eV, 3.8eV, 4eV, 5eV, 6eV, 7eV, 8eV, 9eV, 10eV or 11eV, etc., and there is no limitation here.

[0108] For example, the electron blocking layer 16 is made of a P-type inorganic semiconductor material, and the valence band of the electron blocking layer 16 is about -5eV to -5.5eV. The electron blocking layer 16 has less obstruction to hole transport, which is more conducive to the charge balance of the light-emitting device 10.

[0109] The electron blocking layer 16 can effectively suppress electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14 without blocking hole transport. The following experimental data are provided.

[0110] Figure 8 is a graph showing the relationship between current density and voltage of the light-emitting device 10 according to some embodiments of the present disclosure. The horizontal axis represents voltage in V, and the vertical axis represents current density in mA / cm². 2 .

[0111] The structure of the light-emitting device 10 in Example 1 is the same as described above, and will not be repeated here.

[0112] As shown in Figure 6, the light-emitting device 10 of Embodiment 2 includes: an anode 11, a hole transport layer 14, an electron blocking layer 16, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12 stacked together. The anode 11 is made of ITO, the hole transport layer 14 is made of p-type amorphous silicon, and the thickness d1 of the hole transport layer 14 is 30 nm. The electron blocking layer 16 is made of nickel oxide, and the thickness d2 of the electron blocking layer 16 is 10 nm. The thickness of the quantum dot light-emitting layer 13 is 20 nm. The electron transport layer 15 is made of ZnMgO, and the thickness of the electron transport layer 15 is 50 nm. The cathode 12 is made of Al.

[0113] As shown in Figure 6, the light-emitting device 10 of Embodiment 3 includes: an anode 11, a hole transport layer 14, an electron blocking layer 16, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12 stacked together. The anode 11 is made of ITO, the hole transport layer 14 is made of p-type amorphous silicon, and the thickness d1 of the hole transport layer 14 is 30 nm. The electron blocking layer 16 is made of aluminum oxide, and the thickness d2 of the electron blocking layer 16 is 10 nm. The thickness of the quantum dot light-emitting layer 13 is 20 nm. The electron transport layer 15 is made of ZnMgO, and the thickness of the electron transport layer 15 is 50 nm. The cathode 12 is made of Al.

[0114] As can be seen from Figure 8, when the voltage range is -5V to 7V, the current density of Example 3 is lower than that of Example 1, indicating that electrons and holes are blocked simultaneously under the influence of the electron blocking layer 16 made of aluminum oxide.

[0115] As shown in Example 2, when the voltage is below 2V, the light-emitting device 10 is not turned on. Compared to Example 1, the current density of the light-emitting device 10 provided in Example 2 is lower when the voltage is below 2V, indicating that the electron blocking layer 16, made of nickel oxide, effectively suppresses electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14. However, when the voltage is above 2V, the current density of the light-emitting device 10 provided in Example 2 is not weakened compared to Example 1, and may even be increased, indicating that the electron blocking layer 16 does not affect hole transport.

[0116] In some embodiments, as shown in FIG9, the light-emitting device 10 further includes a negatively charged interface layer 17 located between the hole transport layer 14 and the quantum dot light-emitting layer 13; the material of the negatively charged interface layer 17 includes alkali metal cations and anions having organic groups and acid radicals, and the negative charge number of the negatively charged interface layer 17 is greater than the positive charge number.

[0117] For example, alkali metal cations include sodium, lithium, or potassium, etc., without limitation.

[0118] For example, the acid radical group includes: phosphate group, sulfonic acid group or carboxylic acid group, etc., without limitation.

[0119] By setting a negatively charged interface layer 17 with a negative charge number greater than the positive charge number, the negatively charged interface layer 17 can block the transfer of electrons to the hole transport layer 14 through Coulomb electrostatic repulsion, thereby effectively suppressing electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14. Moreover, the negatively charged interface layer 17 will attract holes in the hole transport layer 14 to transfer rapidly to the quantum dot light-emitting layer 13, improving the hole injection efficiency of the light-emitting device 10.

[0120] In some embodiments, as shown in FIG9, the material of the negatively charged interface layer 17 includes at least one of the following: sodium 1,4-phenylbisphosphonate, sodium poly(vinylphosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalene disulfonate, sodium 1,3-propanedisulfonate, sodium isophenyltrimethylolpropane, sodium citrate, and sodium polyacrylate.

[0121] The structural formula of the material of the negatively charged interface layer 17 is as follows.

[0122] For example, the value of n ranges from 1000 to 100000.

[0123] In the above structural formula, the cation is sodium ion, but the cation can also be lithium ion or potassium ion, etc., and there are no restrictions here.

[0124] For example, the negatively charged interface layer 17 is formed by spin coating of a solution, and the solvent can be water with a concentration of 0.01 mg / mL to 30 mg / mL.

[0125] The cations in the negatively charged interface layer 17 are all alkali metal ions, which are very small in size and fully ionized, allowing them to distribute freely in solution. Their anions, however, have larger organic groups and acid radicals, making them readily adsorbed onto the surface of the preceding film layer (e.g., hole transport layer 14). During the spin-coating process, the cations in the material forming the negatively charged interface layer 17 are easily removed, leaving behind an anion-rich negatively charged interface layer 17.

[0126] The presence of the negatively charged interface layer 17 does not cause a degradation in the photoluminescence quantum yield (PLQY) performance of the quantum dot emitting layer 13. Figure 10 is a fluorescence spectrum of the light-emitting device 10 according to some embodiments of the present disclosure. The horizontal axis represents wavelength in nm, and the vertical axis represents fluorescence intensity in au.

[0127] The structure of the light-emitting device 10 in Example 1 is the same as described above, and will not be repeated here.

[0128] As shown in Figure 9, the light-emitting device 10 of Embodiment 4 includes: an anode 11, a hole transport layer 14, a negatively charged interface layer 17, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12, all stacked together. The anode 11 is made of ITO, the hole transport layer 14 is made of p-type amorphous silicon with a thickness d1 of 30 nm, the negatively charged interface layer 17 is made of sodium polystyrene sulfonate with a thickness d3 of 10 nm, the quantum dot light-emitting layer 13 has a thickness of 20 nm, the electron transport layer 15 is made of ZnMgO with a thickness of 50 nm, and the cathode 12 is made of Al.

[0129] As can be seen from Figure 10, compared with Example 1, the photoluminescent quantum dot yield performance of the light-emitting device 10 provided in Example 4 is very similar, and the two fluorescence spectrum curves almost overlap. This indicates that the provision of the negatively charged interface layer 17 does not lead to a decline in the photoluminescent quantum dot yield performance of the quantum dot light-emitting layer 13.

[0130] In some embodiments, as shown in FIG9, the ratio of the number of atoms of anions to the number of charges of anions in the negatively charged interface layer 17 ranges from 4 to 30.

[0131] For example, the ratio of the number of atoms of anion to the number of charges of anion can be 4, 6, 8, 10, 12, 15, 18, 20, 23, 25, 27, 28 or 30, etc., and there is no limitation here.

[0132] For example, charge detection mass spectrometry (CDMS) is used to test the ratio of the number of anions to the charge of anions in the negatively charged interface layer 17.

[0133] By setting the ratio of the number of atoms of anions to the number of charges of anions to a range of 4 to 30, it can be ensured that the electrical interface layer 17 has a sufficient number of charges, while the anions have sufficiently large groups that can be adsorbed onto the film layer on which the negative electrical interface layer 17 is to be formed.

[0134] In some embodiments, as shown in FIG9, the thickness d3 of the negatively charged interface layer 17 ranges from 0.1 nm to 20 nm.

[0135] For example, the thickness d3 of the negatively charged interface layer 17 can be 0.1nm, 0.5nm, 1nm, 2nm, 3.5nm, 5nm, 7nm, 10nm, 12nm, 15nm, 17nm, 18nm or 20nm, etc., and there is no limitation here.

[0136] By ensuring that the thickness d3 of the negatively charged interface layer 17 is at least the thickness of a molecular dipole, i.e., greater than or equal to 0.1 nm, the negatively charged interface layer 17 can be guaranteed to possess the property of exhibiting negative charge properties. If the thickness d3 of the negatively charged interface layer 17 is less than or equal to 20 nm, the Auger recombination enhancement problem caused by localized charge accumulation due to a thicker thickness d3 can be effectively prevented. Furthermore, since the material of the negatively charged interface layer 17 is an insulating material, setting the thickness d3 of the negatively charged interface layer 17 within the range of 0.1 nm to 20 nm can effectively avoid the negatively charged interface layer 17 affecting charge transport.

[0137] In some embodiments, as shown in FIG11, the light-emitting device 10 includes an electron blocking layer 16 and a negative interface layer 17, wherein the negative interface layer 17 is located on the side of the electron blocking layer 16 away from the anode 11.

[0138] Since the Coulomb electrostatic repulsion of the negatively charged interface layer 17 is affected by distance, the Coulomb electrostatic repulsion force decreases as the distance increases. In order to ensure that the negatively charged interface layer 17 can maximize its effect of blocking the transfer of electrons to the hole transport layer 14, the negatively charged interface layer 17 is located on the side of the electron blocking layer 16 away from the anode 11.

[0139] The electron blocking layer 16 and the negatively charged interface layer 17 form a composite electron blocking layer. The electron blocking layer 16 has a wide bandgap, and the negative charge number of the negatively charged interface layer 17 is greater than the positive charge number. This structure not only builds an electron transfer barrier in the energy band, but also effectively suppresses electron leakage and alleviates interface quenching through the electrostatic repulsion of the negatively charged interface layer 17, thereby improving the quantum yield of the light-emitting device 10.

[0140] Figure 12 is another fluorescence spectrum of the light-emitting device 10 according to some embodiments of the present disclosure.

[0141] The structure of the light-emitting device 10 in Example 1 is the same as described above, and will not be repeated here.

[0142] As shown in Figure 11, the light-emitting device 10 of Embodiment 5 includes: an anode 11, a hole transport layer 14, an electron blocking layer 16, a negatively charged interface layer 17, a quantum dot light-emitting layer 13, an electron transport layer 15, and a cathode 12 stacked together.

[0143] The anode 11 is made of ITO, the hole transport layer 14 is made of p-type amorphous silicon and has a thickness d1 of 30 nm, the electron blocking layer 16 is made of nickel oxide and has a thickness d2 of 10 nm, the negative interface layer 17 is made of sodium polystyrene sulfonate and has a thickness d3 of 10 nm, the quantum dot emitting layer 13 has a thickness of 20 nm, the electron transport layer 15 is made of ZnMgO and has a thickness of 50 nm, and the cathode 12 is made of Al.

[0144] As can be seen from Figure 12, compared with Example 1, the presence of electron blocking layer 16 and negatively charged interface layer 17 increases the fluorescence intensity of light-emitting device 10 by nearly an order of magnitude, thereby contributing to the improvement of the performance of light-emitting device 10.

[0145] In some embodiments, as shown in FIG13, the light-emitting device 10 further includes an auxiliary layer 18 located between the hole transport layer 14 and the quantum dot light-emitting layer 13. The auxiliary layer 18 includes a first type of material and a second type of material. The first type of material includes an organic insulating material; the second type of material includes an alkali metal cation and an anion having organic groups and acid radicals.

[0146] For example, the first type of materials includes at least one of polymethyl methacrylate, polystyrene, and polyethylene terephthalate. The second type of materials includes at least one of sodium 1,4-benzenediphosphonate, sodium poly(vinylphosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalenedisulfonate, sodium 1,3-propanedisulfonate, sodium isophthalate, sodium citrate, and sodium polyacrylate.

[0147] For example, the first type of material and the second type of material can be formed into a film by spin coating process, and therefore, the auxiliary layer 18 can be formed by spin coating process.

[0148] The first type of material is a material with charge blocking effect, and the second type of material is a material that can form a film layer with electrostatic repulsion effect. Therefore, by including the first type of material and the second type of material in the auxiliary layer 18, the auxiliary layer 18 has a similar function to the electron blocking layer 16 and the negatively charged interface layer 17 shown in Figure 11. The auxiliary layer 18 constructs an electron transfer barrier in the energy band and also has an electrostatic repulsion effect, effectively suppressing electron leakage and alleviating interface quenching, so as to improve the quantum yield of the light-emitting device 10.

[0149] In some embodiments, as shown in FIG13, the ratio of the mass of the first type of material to the mass of the second type of material in the auxiliary layer 18 ranges from 0.25 to 0.75.

[0150] For example, the ratio of the mass of the first type of material to the mass of the second type of material is 0.25, 0.3, 0.4, 0.45, 0.5, 0.6, 0.65, 0.7, or 0.75.

[0151] By setting the ratio of the mass of the first type of material to the mass of the second type of material to be in the range of 0.25 to 0.75, the formed auxiliary layer 18 can both build an electron transfer barrier and have an electrostatic repulsion effect, so as to effectively suppress electron leakage, alleviate interface quenching, and improve the quantum yield of the light-emitting device 10.

[0152] In some embodiments, as shown in FIG13, the thickness d4 of the auxiliary layer 18 ranges from 1 nm to 30 nm.

[0153] For example, the thickness d4 of the auxiliary layer 18 can be 1nm, 3nm, 5nm, 7nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm, 23nm, 25nm or 30nm, etc., and there is no limitation here.

[0154] By setting the thickness d4 of the auxiliary layer 18 to be in the range of 1nm to 30nm, the auxiliary layer 18 can not only build an electron transfer barrier, but also have an electrostatic repulsion effect. Moreover, the setting of the auxiliary layer 18 can effectively avoid affecting the charge transport.

[0155] In some embodiments, as shown in FIG14, the material of the portion of the hole transport layer 14 away from the anode 11 further includes a conditioning element, which includes at least one of oxygen, nitrogen and carbon.

[0156] For example, the regulating element includes oxygen, the material of the portion of hole transport layer 14 away from anode 11 includes silicon oxide, the material of hole transport layer 14 along the direction away from anode 11 is a gradient layer from Si to silicon oxide, and the oxygen content gradually increases, so as to increase the band gap of hole transport layer 14 and effectively prevent the injection of electrons into hole transport layer 14.

[0157] For example, the regulating element includes nitrogen, the material of the portion of hole transport layer 14 away from anode 11 includes silicon nitride, the material of hole transport layer 14 along the direction away from anode 11 is a gradient layer from Si to silicon nitride, and the nitrogen content gradually increases, so as to increase the band gap of hole transport layer 14, so as to effectively prevent the injection of electrons into hole transport layer 14.

[0158] For example, the regulating element includes carbon, the material of the portion of the hole transport layer 14 away from the anode 11 includes silicon carbide, and the material of the hole transport layer 14 along the direction away from the anode 11 is a gradient layer from Si to silicon carbide, and the carbon content gradually increases, so as to increase the band gap of the hole transport layer 14, so as to effectively prevent the injection of electrons into the hole transport layer 14.

[0159] For example, the hole transport layer 14 is prepared by adjusting the composition of the above-mentioned regulating elements during the PECVD (plasma-enhanced chemical vapor deposition) process.

[0160] In some embodiments, as shown in FIG14, in the portion of the hole transport layer 14 that includes the regulating element, the ratio of the number of atoms of the regulating element to the number of atoms of silicon atoms is less than or equal to 67 / 33.

[0161] For example, the ratio of the number of atoms of the adjusting element to the number of atoms of silicon can be 67 / 33, 67 / 35, 67 / 40, 67 / 45, 67 / 50, 67 / 60, 67 / 60, 1, 0.5, 0.3, 0.1 or 0.01, etc., and there is no limit here.

[0162] By adjusting the ratio of the number of atoms of the element to the number of atoms of silicon to be less than or equal to 67 / 33, the band gap of the hole transport layer 14 can be increased. This effectively avoids the problem of interstitial oxygen defects caused by excessive adjustment element content, thus effectively preventing electron quenching caused by interstitial oxygen defects.

[0163] In some embodiments, as shown in FIG14, the ratio of the thickness d5 of the portion of the hole transport layer 14 including the adjustment element to the thickness d1 of the hole transport layer 14 is in the range of 0.01 to 0.3, that is, the range of d5 / d1 is 0.01 to 0.3.

[0164] For example, the ratio of the thickness d5 of the portion of the hole transport layer 14 including the adjustment element to the thickness d1 of the hole transport layer 14 is 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.25 or 0.3, etc., and there is no limitation here.

[0165] By setting the ratio of the thickness d5 of the portion of the hole transport layer 14 including the adjustment element to the thickness d1 of the hole transport layer 14 to be in the range of 0.01 to 0.3, while ensuring that the hole transport layer 14 has a suitable valence band depth and excellent hole mobility, the band gap of the hole transport layer 14 is increased. The component can effectively solve the problem of performance degradation of the light-emitting device 10, and can also effectively suppress the problem of electron leakage from the quantum dot light-emitting layer 13 to the hole transport layer 14, thereby improving the quantum yield of the light-emitting device 10.

[0166] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A light-emitting device, comprising: An anode, a cathode, a quantum dot light-emitting layer located between the anode and the cathode, and a hole transport layer located between the anode and the quantum dot light-emitting layer; The material of the hole transport layer includes P-type amorphous silicon.

2. The light-emitting device according to claim 1, further comprising: An electron blocking layer is located between the hole transport layer and the quantum dot light-emitting layer, wherein the electron blocking layer is made of at least one of an insulating material and a P-type semiconductor material.

3. The light-emitting device according to claim 2, wherein, The conduction band of the electron blocking layer material is greater than or equal to -3.0 eV, the valence band of the electron blocking layer material is less than or equal to -5 eV, and the band gap of the electron blocking layer material is greater than or equal to 3 eV.

4. The light-emitting device according to claim 2 or 3, wherein, The electron blocking layer is made of at least one of the following materials: aluminum oxide, hafnium dioxide, polymethyl methacrylate, polystyrene, polyethylene terephthalate, cuprous thiocyanate, nickel oxide, tungsten trioxide, copper oxide, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)], and polyvinylcarbazole.

5. The light-emitting device according to any one of claims 2 to 4, wherein, The electron blocking layer is made of an insulating material, and the thickness of the electron blocking layer ranges from 1 nm to 30 nm; or, The electron blocking layer is made of a P-type semiconductor material, and the thickness of the electron blocking layer ranges from 1 nm to 100 nm.

6. The light-emitting device according to any one of claims 1 to 5, further comprising: A negatively charged interface layer located between the hole transport layer and the quantum dot emitting layer; The material of the negatively charged interface layer includes: alkali metal cations and anions having organic groups and acid radicals; wherein the number of negative charges in the negatively charged interface layer is greater than the number of positive charges.

7. The light-emitting device according to claim 6, wherein, The material of the negative electrical interface layer includes at least one of the following: sodium 1,4-benzyl bisphosphonate, sodium poly(vinyl phosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalene disulfonate, sodium 1,3-propanedisulfonate, sodium isophenyltrimethylolpropane, sodium citrate, and sodium polyacrylate.

8. The light-emitting device according to claim 6 or 7, wherein, In the negatively charged interface layer, the ratio of the number of atoms of the anion to the charge of the anion ranges from 4 to 30.

9. The light-emitting device according to any one of claims 6 to 8, wherein, The thickness of the negatively charged interface layer ranges from 0.1 nm to 20 nm.

10. The light-emitting device according to any one of claims 6 to 9, wherein, The light-emitting device includes an electron blocking layer, and the negatively charged interface layer is located on the side of the electron blocking layer away from the anode.

11. The light-emitting device according to claim 1, further comprising: An auxiliary layer located between the hole transport layer and the quantum dot light-emitting layer, the auxiliary layer comprising: a first type of material and a second type of material; The first category of materials includes: organic insulating materials; the second category of materials includes: alkali metal cations and anions having organic groups and acid radicals.

12. The light-emitting device according to claim 11, wherein, The first type of material includes at least one of polymethyl methacrylate, polystyrene, and polyethylene terephthalate; The second category of materials includes at least one of the following: sodium 1,4-benzyl phosphonate, sodium poly(vinyl phosphonate), sodium [1,1'-biphenyl]-4,4'-dimethylbis(phosphonate), sodium polystyrene sulfonate, sodium 1,5-naphthalene disulfonate, sodium 1,3-propanedisulfonate, sodium isophenyltrimethylolpropane, sodium citrate, and sodium polyacrylate.

13. The light-emitting device according to claim 12, wherein, In the auxiliary layer, the ratio of the mass of the first type of material to the mass of the second type of material ranges from 0.25 to 0.

75.

14. The light-emitting device according to claim 12 or 13, wherein, The thickness of the auxiliary layer ranges from 1 nm to 30 nm.

15. The light-emitting device according to any one of claims 1 to 14, wherein, The P-type doped material in the P-type amorphous silicon includes at least one of trimethylborane, borane, and boron trichloride.

16. The light-emitting device according to any one of claims 1 to 15, wherein, In the p-type amorphous silicon, the doping concentration of the p-type doped material ranges from 10. 17 / cm 3 ~10 20 / cm 3 .

17. The light-emitting device according to any one of claims 1 to 16, wherein, The thickness of the hole transport layer ranges from 5 nm to 100 nm.

18. The light-emitting device according to any one of claims 1 to 17, wherein, The Fermi level of the hole transport layer ranges from -4.5 eV to -5.8 eV.

19. The light-emitting device according to any one of claims 1 to 18, wherein, The material of the portion of the hole transport layer away from the anode further includes a regulating element, which includes at least one of oxygen, nitrogen, and carbon.

20. The light-emitting device according to claim 19, wherein, In the portion of the hole transport layer that includes the regulating element, the ratio of the number of atoms of the regulating element to the number of atoms of silicon is less than or equal to 67 / 33.

21. The light-emitting device according to claim 19 or 20, wherein, The ratio of the thickness of the portion of the hole transport layer including the regulating element to the thickness of the hole transport layer ranges from 0.01 to 0.

3.

22. A display panel, comprising: The pixel-defining layer has multiple openings; Multiple light-emitting devices are arranged one-to-one in the multiple openings; At least one of the plurality of light-emitting devices is a light-emitting device as described in any one of claims 1 to 21.

23. A display device, comprising: The display panel as described in claim 22; A driver chip is used to drive the display panel to display.

Images