Quantum dot light emitting diode and preparation method thereof

Abstract

The application discloses a quantum dot light emitting diode and a preparation method thereof. The preparation method comprises the following steps: depositing a quantum dot solution on a prefabricated device, wherein the quantum dot solution comprises an organic solvent and quantum dot materials dispersed in the organic solvent; and performing gamma ray irradiation treatment on the quantum dot solution to form a quantum dot light emitting layer on the prefabricated device. The gamma ray irradiation treatment on the quantum dot light emitting layer can effectively improve the photoelectric performance of the quantum light emitting diode and improve the performance test efficiency of the quantum light emitting diode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum dot light emitting diode, and particularly relates to a quantum dot light emitting diode and a preparation method thereof. BACKGROUND

[0002] Quantum dots light-emitting diode (QLED) is a new type of display device, which has a similar structure to organic light-emitting diode (OLED) and is composed of a cathode, a hole transport layer, a light-emitting layer, an electron transport layer and an anode. When an external voltage is applied, electrons and holes are injected from the respective electrodes, and the two recombine to emit light. QLED is a new technology between liquid crystal and OLED, and the core technology of QLED is "quantum dots". Quantum dots are particles with a diameter of less than 10 nm, which are composed of zinc, cadmium, sulfur and selenium atoms. This substance has a very special property: when quantum dots are stimulated by light and electricity, they will emit colored light, and the color is determined by the material that makes up the quantum dots and its size and shape. Because of this property, it can change the color of the light emitted by the light source. The wavelength range of quantum dot light is very narrow, the color is relatively pure, and it can be adjusted, so the picture of quantum dot display will be clearer and brighter than that of liquid crystal display.

[0003] Compared with OLED, the feature of QLED is that its light-emitting material uses inorganic quantum dots with more stable performance. The unique quantum size effect, macroscopic quantum tunneling effect, quantum size effect and surface effect of quantum dots make them exhibit excellent physical properties, especially their optical properties. Compared with organic fluorescent dyes, quantum dots prepared by colloidal method have the advantages of tunable spectrum, high light intensity, high color purity, long fluorescence lifetime, and single light source can excite multi-color fluorescence. In addition, QLED has a long service life, and its packaging process is simple or unnecessary, which is expected to become the next generation of flat panel display and has broad development prospects. QLED is based on inorganic semiconductor quantum dots electroluminescence. In theory, the stability of inorganic semiconductor quantum dots is higher than that of organic small molecules and polymers. On the other hand, due to the quantum confinement effect, the light-emitting line width of quantum dot material is smaller, so it has better color purity. At present, the light-emitting efficiency of QLED has basically reached the demand of commercialization.

[0004] However, the performance of the actual QLED device prepared at the present stage does not reach the expected level, and the phenomenon of fluorescence quenching occurs. This problem is closely related to the defect states of the quantum dot light-emitting layer, which easily leads to poor photoelectric performance of the quantum dot light-emitting diode.

[0005] Therefore, the prior art remains to be improved and developed. SUMMARY

[0006] In view of the deficiencies of the prior art described above, the purpose of the present application is to provide a quantum dot light emitting diode and a preparation method thereof, aiming to solve the problem that the quantum dot light emitting layer has defect states, resulting in poor photoelectric performance of the quantum dot light emitting diode.

[0007] The technical solutions of the present application are as follows:

[0008] A preparation method of a quantum dot light emitting diode, comprising the following steps:

[0009] Depositing a quantum dot solution on the prefabricated device, the quantum dot solution comprising an organic solvent and quantum dot materials dispersed in the organic solvent;

[0010] Using gamma rays to irradiate and treat the quantum dot solution to form a quantum dot light emitting layer on the prefabricated device.

[0011] A quantum dot light emitting diode, comprising a quantum dot light emitting layer, which is prepared by irradiating and treating a quantum dot solution with gamma rays.

[0012] Beneficial effects: The present application provides a preparation method of a quantum dot light emitting diode, which uses gamma ray annealing to anneal the quantum dot light emitting layer. Gamma rays are essentially short-wavelength electromagnetic waves, and have the characteristics of short wavelength, high energy, and strong penetration ability. Therefore, irradiating the quantum dot light emitting layer with gamma rays can achieve the effect of post-annealing. After post-annealing, the molecular arrangement is more ordered, the carrier mobility is improved, and the accumulation of interface charges leading to fluorescence quenching of the device is avoided. This process effectively reduces the thermal budget. Compared with traditional thermal annealing, the annealing mechanism of gamma rays has special properties. It not only achieves the purpose of traditional annealing, but also improves the photoelectric performance of quantum dot devices and has a beneficial effect on the precision of QLED performance testing. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 A flowchart of a preferred embodiment of a preparation method of a quantum dot light emitting diode provided by the present application.

[0014] Figure 2 A structure schematic diagram of a preferred embodiment of a quantum dot light emitting diode with a normal structure provided by the present application.

[0015] Figure 3 A structure schematic diagram of a preferred embodiment of a quantum dot light emitting diode with an inverted structure provided by the present application.

[0016] Figure 4The current efficiency test results of the quantum dot light emitting diode prepared for example 1 and comparative example 1 are compared.

[0017] Figure 5 The life curve and forward aging interval of the quantum dot light emitting diode prepared for comparative example 1 are shown in the schematic diagram.

[0018] Figure 6 The life curve and forward aging interval of the quantum dot light emitting diode prepared for example 1 are shown in the schematic diagram. DETAILED DESCRIPTION

[0019] The present application provides a quantum dot light emitting diode and a preparation method thereof, in order to make the purpose, technical scheme and effect of the present application more clear and explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0020] Under normal circumstances, the electron-hole pairs (excitons) generated in the quantum dots should first relax in the band, and then recombine at the band edge to emit photons. If the quantum dot light emitting layer has defects, the excitons may relax to the defect energy level. Because other relaxation and recombination pathways are added, the decay dynamics of the excitons will change, and because the defect state often has a high probability of non-radiative transition, the light emitting ability of the quantum dot light emitting layer with defects will be weakened, thereby leading to poor photoelectric performance of the quantum dot light emitting diode.

[0021] Based on this, the present application provides a preparation method of a quantum dot light emitting diode, as shown in Figure 1 The preparation method comprises the steps of:

[0022] S10, depositing a quantum dot solution on a pre-prepared device, the quantum dot solution comprising an organic solvent and quantum dot materials dispersed in the organic solvent;

[0023] S20, irradiating the quantum dot solution with gamma rays to form a quantum dot light emitting layer on the pre-prepared device.

[0024] In this embodiment, the quantum dot solution deposited on the pre-prepared device is irradiated with gamma rays to form a quantum dot light emitting layer, which can effectively improve the photoelectric performance of the quantum light emitting diode. The action mechanism is as follows:

[0025] Gamma rays are actually electromagnetic waves with extremely short wavelength and high energy. Part of the gamma rays is converted into heat energy, causing the temperature of the object to rise. Therefore, irradiating the quantum dot solution with gamma rays in this embodiment can have a post-annealing effect. After post-annealing treatment, the quantum dots in the quantum dot light emitting layer can be arranged more orderly, thereby improving the carrier mobility of the quantum dot light emitting layer.

[0026] The gamma rays have a high penetration, and can remove residual organic solvents in the quantum dot light-emitting layer, and improve the light-emitting efficiency of the quantum dot light-emitting layer.

[0027] Meanwhile, when the quantum dot solution is irradiated by the gamma rays, the electrons in the quantum dot solution can fill the defect states in the film layer, improve the Coulomb efficiency, and have a beneficial effect on the light-emitting efficiency of the quantum dot light-emitting layer, thereby improving the photoelectric performance of the quantum dot light-emitting diode.

[0028] Further, in the performance test of the quantum dot light-emitting diode, a long time is required for the device state to reach an optimal value after the power supply is driven, but the longer the time for the device state to reach the optimal value, the greater the damage to the device. Therefore, how to accelerate the aging of the device before the life test to shorten the time for the device state to reach the optimal value is also an important research topic.

[0029] The gamma ray irradiation treatment of the quantum dot solution can effectively improve the precision of the performance test of the QLED, and the mechanism is as follows:

[0030] The gamma rays are essentially short-wavelength electromagnetic waves. When the gamma rays pass through the quantum dot light-emitting layer and interact with the atoms, a photoelectric effect occurs, which has a certain aging effect on the quantum dot light-emitting layer. However, the performance of the quantum dot device is in a rising state for a certain period of time after being driven. In the process of the working life test, the greater the rising time and amplitude, the more obvious the effect on the test. The short-time low-intensity gamma ray irradiation treatment has a positive aging effect on the device, i.e., excitation of the quantum dot material. The short-time annealing process has the equivalent effect of a longer and appropriate time of power-on aging, which can shorten the performance test time, thereby effectively improving the efficiency of the device performance test.

[0031] In some embodiments, the irradiation intensity in the step of irradiating the quantum dot solution with gamma rays is 5-15 Gy.

[0032] In the present embodiment, if the irradiation intensity is less than 5 Gy, the ideal annealing degree cannot be achieved, which affects the performance of the device. If the irradiation intensity is higher than 15 Gy, the high-energy gamma rays may damage the structure of the quantum dots, causing fluorescence quenching.

[0033] In some embodiments, the irradiation dose rate in the step of irradiating the quantum dot solution with gamma rays is 1-1.5 Gy / s.

[0034] In the present embodiment, if the irradiation dose rate is less than 1 Gy / s, the annealing efficiency is slow; if the irradiation dose rate is greater than 1.5 Gy / s, the energy rises too fast, which is easy to cause damage to the quantum dot structure, resulting in fluorescence quenching.

[0035] In some embodiments, the quantum dot material is a direct bandgap compound semiconductor with light emitting capability, including but not limited to one or more of a II-VI compound, a III-V compound, a II-V compound, a III-VI compound, a IV-VI compound, a I-III-VI compound, a II-IV-VI compound, or a IV element.

[0036] In particular, the semiconductor material used in the quantum dot light emitting layer of the present embodiment includes but is not limited to nanocrystals of II-VI semiconductors such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, PbS, PbSe, PbTe and other binary, ternary, quaternary II-VI compounds; nanocrystals of III-V semiconductors such as GaP, GaAs, InP, InAs and other binary, ternary, quaternary III-V compounds; the semiconductor material used for electroluminescence is not limited to II-V compounds, III-VI compounds, IV-VI compounds, I-III-VI compounds, II-IV-VI compounds, IV element, etc.

[0037] In some embodiments, the quantum dot material is one of a non-doped inorganic perovskite semiconductor, a doped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor, but is not limited thereto.

[0038] In particular, the structure of the inorganic perovskite semiconductor has a general formula of AMY3, wherein A is Cs + ion, M is a divalent metal cation, including but not limited to Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ , Y is a halide anion, including but not limited to Cl - , Br - , I -; the structure of the organic-inorganic hybrid perovskite type semiconductor is BMY3, wherein B is an organic amine cation, including but not limited to CH3(CH2) n-2 NH3 + (n≥2) or NH3(CH2) n NH3 2+ (n≥2). When n = 2, the inorganic metal halide octahedron MY 64- is connected in a shared vertex manner, the metal cation M is located in the body center of the halogen octahedron, and the organic amine cation B fills the gap between the octahedrons to form an infinite three-dimensional structure; when n > 2, the inorganic metal halide octahedron MY 64- is connected in a shared vertex manner, and extends in a two-dimensional direction to form a layered structure, and the organic amine cation bilayer (protonated monoamine) or the organic amine cation monolayer (protonated diamine) is inserted between the layers, and the organic layer and the inorganic layer are overlapped to form a stable two-dimensional layered structure; M is a divalent metal cation, including but not limited to Pb 2+ , Sn 2 + , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ ; Y is a halide anion, including but not limited to Cl - , Br - , I - .

[0039] In some embodiments, when the prepared quantum dot light emitting diode is a normal structure, the substrate comprises a substrate, an anode, a hole functional layer, and an electron functional layer which are sequentially stacked from bottom to top. Figure 2 The preparation of the quantum dot light emitting diode comprises the following steps:

[0040] S01, preparing an anode on the substrate;

[0041] S02, preparing a hole functional layer on the anode;

[0042] S03, depositing a quantum dot solution on the hole functional layer;

[0043] S04, irradiating the quantum dot solution with γ rays to form a quantum dot light emitting layer on the hole functional layer;

[0044] S05, preparing an electron functional layer on the quantum dot light emitting layer;

[0045] S06, preparing a cathode on the electronic functional layer to obtain the quantum dot light emitting diode.

[0046] In the embodiment, the hole functional layer comprises one or more of an electron blocking layer, a hole injection layer and a hole transport layer, but is not limited thereto; the electronic functional layer comprises one or more of a hole blocking layer, an electron injection layer and an electron transport layer, but is not limited thereto.

[0047] In the embodiment, the preparation method of each layer can be a chemical method or a physical method, wherein the chemical method comprises one or more of chemical vapor deposition, successive ion layer adsorption and reaction, anodic oxidation, electrolytic deposition and coprecipitation, but is not limited thereto; the physical method comprises one or more of a solution method (such as spin coating, printing, blade coating, dip-coating, immersion, spraying, roll coating, casting, slot coating or stripe coating), evaporation (such as thermal evaporation, electron beam evaporation, magnetron sputtering or multi-arc ion plating), deposition (such as physical vapor deposition, atomic layer deposition or pulsed laser deposition), but is not limited thereto.

[0048] In other embodiments, when the prepared quantum dot light emitting diode is an inverted structure, the substrate comprises a substrate, a cathode, an electronic functional layer, a quantum dot light emitting layer, a hole functional layer and an anode which are sequentially stacked from bottom to top, as shown in Figure 2 The preparation of the quantum dot light emitting diode comprises the steps of:

[0049] S100, preparing a cathode on the substrate;

[0050] S200, preparing an electronic functional layer on the cathode;

[0051] S300, depositing a quantum dot solution on the electronic functional layer;

[0052] S400, irradiating the quantum dot solution with a gamma ray to form a quantum dot light emitting layer on the electronic functional layer;

[0053] S500, preparing a hole functional layer on the quantum dot light emitting layer;

[0054] S600, preparing an anode on the hole functional layer to obtain the quantum dot light emitting diode.

[0055] In the embodiment, the hole functional layer comprises one or more of an electron blocking layer, a hole injection layer and a hole transport layer, but is not limited thereto; the electronic functional layer comprises one or more of a hole blocking layer, an electron injection layer and an electron transport layer, but is not limited thereto.

[0056] In the embodiment, the preparation method of each layer can be a chemical method or a physical method, wherein the chemical method includes but is not limited to one or more of a chemical vapor deposition method, a successive ion layer adsorption and reaction method, an anodic oxidation method, an electrolytic deposition method, and a coprecipitation method; and the physical method includes but is not limited to one or more of a solution method (such as a spin coating method, a printing method, a blade coating method, an immersion pulling method, an immersion method, a spray coating method, a roll coating method, a casting method, a slot coating method, or a strip coating method), an evaporation method (such as a thermal evaporation method, an electron beam evaporation method, a magnetron sputtering method, or a multi-arc ion plating method), and a deposition method (such as a physical vapor deposition method, an atomic layer deposition method, or a pulsed laser deposition method).

[0057] In some embodiments, a quantum dot light emitting diode is also provided, which comprises a quantum dot light emitting layer prepared by irradiating a quantum dot solution with gamma rays.

[0058] In the embodiment, the quantum dot light emitting layer is formed by irradiating a quantum dot solution with gamma rays, which can effectively improve the photoelectric performance of the quantum dot light emitting diode, and the mechanism is as follows:

[0059] Gamma rays are actually electromagnetic waves with extremely short wavelengths and high energy. Part of the gamma rays is converted into heat energy, which increases the temperature of the object. Therefore, the irradiation of the quantum dot solution with gamma rays in the embodiment can have a post-annealing effect. After the post-annealing treatment, the quantum dots in the quantum dot light emitting layer can be arranged more orderly, and the carrier mobility of the quantum dot light emitting layer can be improved.

[0060] When the material is irradiated with gamma rays, the temperature increases rapidly. Compared with conventional thermal annealing, the annealing precision can be more accurately controlled, and the negative impact on the quantum dot light emitting layer with high thermal sensitivity can be reduced. Meanwhile, the high penetration of gamma rays can more fully remove the residual organic solvent in the quantum dot light emitting layer, and improve the light emitting efficiency of the quantum dot light emitting layer.

[0061] Meanwhile, when the quantum dot solution is irradiated with gamma rays, the photons can excite electrons, and the electrons in the quantum dot light emitting layer can fill the defect states in the film layer, improve the Coulomb efficiency, and have a beneficial effect on the light emitting efficiency of the quantum dot light emitting layer, thereby improving the photoelectric performance of the quantum dot light emitting diode.

[0062] Further, the irradiation of the quantum dot light emitting layer with gamma rays can effectively improve the precision of the performance test of the QLED, and the mechanism is as follows:

[0063] The γ-ray is essentially a short-wavelength electromagnetic wave. When the γ-ray passes through the quantum dot light-emitting layer, photoelectric effect occurs when the γ-ray interacts with atoms of the quantum dot light-emitting layer, which has a certain aging effect on the quantum dot light-emitting layer. However, the performance of the quantum dot device is in a rising state for a considerable period of time after the device is driven. The greater the rising time and amplitude, the more obvious the effect on the test during the working life test. The short-time low-intensity γ-ray irradiation treatment has a positive aging effect on the device, that is, the quantum dot material is excited, and the short-time annealing process has the equivalent effect of a longer and appropriate time of electrical aging, which can effectively improve the precision of the device performance test.

[0064] In some specific embodiments, a quantum dot light-emitting diode of an upright structure is provided, which comprises a substrate, an anode, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode which are sequentially stacked from bottom to top, and the quantum dot light-emitting layer is subjected to γ-ray irradiation treatment.

[0065] In some specific embodiments, a quantum dot light-emitting diode of an inverted structure is also provided, which comprises a substrate, a cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and an anode which are sequentially stacked from bottom to top, and the quantum dot light-emitting layer is subjected to γ-ray irradiation treatment.

[0066] In some embodiments, the anode material is selected from one or more of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO) and aluminum-doped magnesium oxide (AMO), but is not limited thereto.

[0067] In some embodiments, the hole transport layer material is selected from one or more of poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB), polyvinylcarbazole (PVK), poly(N,N'bis(4-butylphenyl)-N,N'-bis(phenyl)phenylamine) (Poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA), 4,4'-bis(9-carbazolyl) biphenyl (CBP), N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), but is not limited thereto.

[0068] In some embodiments, the electron transport layer is selected from one or more of ZnO, TiO, NiO, W2O3, Mo2O3, SnO, ZrO2, and Ta2O3, but is not limited thereto.

[0069] In some embodiments, the cathode can be Au, Ag, Al, Cu, Mo, or alloys thereof, but is not limited thereto.

[0070] In some embodiments, the anode has a thickness of 5-120 nm.

[0071] In some embodiments, the hole transport layer has a thickness of 30-120 nm.

[0072] In some embodiments, the quantum dot light-emitting layer has a thickness of 10-200 nm.

[0073] In some embodiments, the electron transport layer has a thickness of 5-100 nm.

[0074] In some embodiments, the cathode has a thickness of 5-120 nm.

[0075] The preparation method and performance of the quantum dot light-emitting diode are further explained and described below through specific examples:

[0076] Comparative Example 1

[0077] A preparation method of a quantum dot light-emitting diode with an upside-down top-emitting structure includes the following steps:

[0078] 1) On an ITO substrate, spin-coat PEDOT:PSS at a speed of 5000 rpm for 30 seconds, and then heat at 150°C for 15 minutes;

[0079] 2) Spin-coat TFB (8 mg / mL) at a speed of 3000 rpm for 30 seconds, and then heat at 80°C for 10 minutes;

[0080] 3) Spin-coat quantum dots (20 mg / mL) at a speed of 2000 rpm for 30 seconds, and then heat at 80°C for 10 minutes;

[0081] 4) Spin-coat ZnO (30 mg / mL) at a speed of 3000 rpm for 30 seconds, and then heat at 80°C for 30 minutes;

[0082] 5) By thermal evaporation, the vacuum degree is not higher than 3 y 10 -4 -6) Evaporate Ag at a speed of 1 angstrom / second for 200 seconds to a thickness of 20 nm, to obtain a quantum dot light-emitting diode with an upside-down top-emitting structure.

[0083] Example 1

[0084] A preparation method of a quantum dot light emitting diode with a normal top emission structure, comprising the following steps:

[0085] 1) On an ITO substrate, spin-coat PEDOT:PSS at 5000 rpm for 30 seconds, and then heat at 150°C for 15 minutes;

[0086] 2) Spin-coat TFB (8 mg / mL) at 3000 rpm for 30 seconds, and then heat at 80°C for 10 minutes;

[0087] 3) Spin-coat quantum dots (20 mg / mL) at 2000 rpm for 30 seconds;

[0088] 4) Irradiate the film using γ-rays at an irradiation intensity of 12 Gy, an irradiation dose rate of 1.5 Gy / s, and an irradiation time of 8 seconds;

[0089] 5) Spin-coat ZnO (30 mg / mL) at 3000 rpm for 30 seconds, and then heat at 80°C for 30 minutes;

[0090] 6) By thermal evaporation, evaporate Ag at a vacuum degree of not higher than 3y10 -4 -6 Pa, at a speed of 1 angstrom / s for 200 seconds, to a thickness of 20 nm, to obtain a normal top emission quantum dot light emitting diode.

[0091] The current efficiency of the quantum dot light emitting diodes prepared in Example 1 and Comparative Example 1 was tested. The quantum dot light emitting diodes were connected to different driving voltages, and the current efficiency was measured. The results are shown in Figure 4 From Figure 4 it can be seen that, under the same driving voltage conditions, the current efficiency of the quantum dot light emitting diode prepared in Example 1 is significantly higher than that of the quantum dot light emitting diode prepared in Comparative Example 1.

[0092] After the quantum dot light emitting diode prepared in Comparative Example 1 was packaged, the working life data of the device was tested. The working life of the device was determined using a constant current drive of 2 mA. The working life curve and the schematic diagram of the forward aging interval are shown in Figure 5 , and the working life data is shown in Table 1.

[0093] After the quantum dot light emitting diode prepared in Example 1 was packaged, the working life data of the device was tested. The working life of the device was determined using a constant current drive of 2 mA. The working life curve and the schematic diagram of the forward aging interval are shown in Figure 6 , and the working life data is shown in Table 1.

[0094]

[0095] Comparison Figure 5 and Figure 6It can be seen that the luminance rise of the device in Comparative Example 1 is 5.4h, while the luminance rise of the device in the present embodiment 1 is 2.5h, which shows that the gamma ray irradiation treatment has a positive effect on the device, and can effectively improve the efficiency of the device life test. In Table 1, L(cd / m 2 ) represents the maximum luminance of the device; T95(h) represents the time required for the luminance to decay to 95% under the driving of a constant current of 2mA; T95_1K(h) represents the time required for the luminance to decay to 95% when the luminance is 1000nit. As can be seen from the data in Table 1, the maximum luminance of the quantum dot light-emitting diode prepared in the present embodiment 1 is 77610cd / m 2 , which is significantly higher than the maximum luminance 71030cd / m 2 of the quantum dot light-emitting diode prepared in Comparative Example 1; the time required for the luminance of the quantum dot light-emitting diode prepared in the present embodiment 1 to decay to 95% under the driving of a constant current of 2mA is 10.1h, which is significantly higher than the time required for the luminance of the quantum dot light-emitting diode prepared in Comparative Example 1 to decay to 95% under the driving of a constant current of 2mA, which is 7.3h; the time required for the luminance of the quantum dot light-emitting diode prepared in the present embodiment 1 to decay to 95% when the luminance is 1000nit is 16489, which is significantly higher than the time required for the luminance of the quantum dot light-emitting diode prepared in Comparative Example 1 to decay to 95% when the luminance is 1000nit, which is 10251h.

[0096] In summary, the present application uses gamma ray annealing to anneal the quantum dot solution. Gamma rays are essentially short-wavelength electromagnetic waves, and have the characteristics of short wavelength, high energy and strong penetration ability. Therefore, irradiating the quantum dot light-emitting layer with gamma rays can have the effect of post-annealing, which makes the molecular arrangement more ordered, improves the carrier mobility, and avoids the accumulation of interface charges leading to fluorescence quenching of the device. This process effectively reduces the thermal budget. Compared with traditional thermal annealing, the annealing mechanism of gamma rays has particularity, which not only can achieve the purpose of traditional annealing, but also can improve the photoelectric performance of the quantum dot device, and has a beneficial effect on the accuracy of QLED performance test.

[0097] It should be understood that the application of the present application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A method for fabricating a quantum dot light-emitting diode, characterized in that, The method comprises the steps of: depositing a quantum dot solution on a pre-prepared device, the quantum dot solution comprising an organic solvent and quantum dot material dispersed in the organic solvent; irradiating the quantum dot solution with gamma rays to form a quantum dot light-emitting layer on the pre-prepared device; in the step of irradiating the quantum dot solution with gamma rays, the irradiation intensity is 5-15 Gy; in the step of irradiating the quantum dot solution with gamma rays, the irradiation dose rate is 1-1.5 Gy / s.

2. The method for fabricating a quantum dot light-emitting diode according to claim 1, characterized in that, The quantum dot material is one or more of a II-VI compound, a III-V compound, a II-V compound, a III-VI compound, a IV-VI compound, a I-III-VI compound, a II-IV-VI compound, or a IV element.

3. The method for fabricating a quantum dot light-emitting diode according to claim 2, characterized in that, The quantum dot material is one of a non-doped inorganic perovskite semiconductor, a doped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor.

4. The method for fabricating a quantum dot light-emitting diode according to claim 1, characterized in that, The pre-prepared device comprises, from bottom to top, a substrate, an anode, and a hole functional layer, and the preparation of the pre-prepared device comprises the steps of: preparing an anode on the substrate; preparing a hole functional layer on the anode; Alternatively, the pre-prepared device comprises, from bottom to top, a substrate, a cathode, and an electron functional layer, and the preparation of the pre-prepared device comprises the steps of: preparing a cathode on the substrate; preparing an electron functional layer on the cathode.

5. The method for fabricating a quantum dot light-emitting diode according to claim 1, characterized in that, After the step of irradiating the quantum dot solution with gamma rays to form a quantum dot light-emitting layer on the pre-prepared device, the method further comprises the steps of: preparing a hole functional layer on the quantum dot light-emitting layer; preparing an anode on the hole functional layer to obtain the quantum dot light-emitting diode; Alternatively, preparing an electron functional layer on the quantum dot light-emitting layer; preparing a cathode on the electron functional layer to obtain the quantum dot light-emitting diode.

6. The method for fabricating a quantum dot light-emitting diode according to any one of claims 4-5, characterized in that, The hole functional layer comprises one or more of an electron blocking layer, a hole injection layer, and a hole transport layer.

7. The method for fabricating a quantum dot light-emitting diode according to any one of claims 4-5, characterized in that, The electron functional layer comprises one or more of a hole blocking layer, an electron injection layer, and an electron transport layer.

8. A quantum dot light emitting diode prepared by the method of any one of claims 1-7. The quantum dot light-emitting layer is prepared by irradiating a quantum dot solution with gamma rays; The irradiation intensity of the irradiation treatment is 5-15 Gy, and the irradiation dose rate is 1-1.5 Gy / s.

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