CN114695808A - Quantum dot light-emitting diode and preparation method thereof - Google Patents
Quantum dot light-emitting diode and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a quantum dot light-emitting diode and a preparation method thereof, wherein 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 a quantum dot material dispersed in the organic solvent; and irradiating the quantum dot solution by adopting gamma rays to form a quantum dot light-emitting layer on the prefabricated device. The invention can effectively improve the photoelectric performance of the quantum dot light-emitting diode and improve the efficiency of the performance test of the quantum dot light-emitting diode by carrying out gamma ray irradiation treatment on the quantum dot light-emitting layer.
Description
Technical Field
The invention relates to the field of quantum dot light-emitting diodes, in particular to a quantum dot light-emitting diode and a preparation method thereof.
Background
Quantum dot Light-Emitting diodes (QLEDs) are a new type of display device, and their structure is similar to Organic Light-Emitting diodes (OLEDs), and they are a structure composed of a cathode, a hole transport layer, a Light-Emitting layer, an electron transport layer and an anode, and when a voltage is applied, electrons and holes are injected from their respective electrodes, and they emit Light compositely. The QLED is a novel technology between liquid crystal and OLED, the core technology of the QLED is Quantum Dot, and the Quantum Dot is a particle with the particle diameter less than 10nm and consists of zinc, cadmium, sulfur and selenium atoms. This substance has a very particular property: when the quantum dots are stimulated by photoelectricity, colored light can be emitted, and the color is determined by the material of the quantum dots and the size and the shape of the material. Because of this property, the color of the light emitted by the light source can be changed. The light-emitting wavelength range of the quantum dots is very narrow, the colors are pure, and the adjustment can be carried out, so that the picture of the quantum dot display is clearer and brighter than that of the liquid crystal display.
Compared with OLED, QLED features its luminescent material of 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 enable them to exhibit excellent physical properties, especially their optical properties. Compared with organic fluorescent dye, the quantum dot prepared by the colloid method has the advantages of adjustable spectrum, high luminous intensity, high color purity, long fluorescence service life, capability of exciting multicolor fluorescence by a single light source and the like. In addition, the QLED has long service life, simple packaging process or no need of packaging, is expected to become a next-generation flat panel display, and has wide development prospect. QLEDs are based on electroluminescence of inorganic semiconductor quantum dots, which theoretically have higher stability than organic small molecules and polymers; on the other hand, due to the quantum confinement effect, the luminous line width of the quantum dot material is smaller, so that the quantum dot material has better color purity. Currently, the luminous efficiency of QLEDs has substantially reached the commercialization demand.
However, the performance of the actual QLED device prepared at the present stage does not reach the due height, and a phenomenon of fluorescence quenching occurs, the occurrence of the problem has a great correlation with the defect state of the quantum dot light emitting layer, and the defect state of the quantum dot light emitting layer easily causes the poor photoelectric performance of the quantum dot light emitting diode.
Accordingly, the prior art is yet to be improved and developed.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, the present invention aims to provide a quantum dot light emitting diode and a method for manufacturing the same, which aims to solve the problem that the photoelectric performance of the quantum dot light emitting diode is poor due to the defect state of the quantum dot light emitting layer.
The technical scheme of the invention is as follows:
a preparation method of a quantum dot light-emitting diode comprises the following steps:
depositing a quantum dot solution on a prefabricated device, wherein the quantum dot solution comprises an organic solvent and a quantum dot material dispersed in the organic solvent;
and irradiating the quantum dot solution by adopting gamma rays to form a quantum dot light-emitting layer on the prefabricated device.
A quantum dot light-emitting diode comprises a quantum dot light-emitting layer, wherein the quantum dot light-emitting layer is prepared by carrying out gamma ray irradiation treatment on a quantum dot solution.
Has the beneficial effects that: the invention provides a preparation method of a quantum dot light-emitting diode, which anneals a quantum dot light-emitting layer by using a gamma ray annealing mode, wherein the gamma ray is essentially short-wavelength electromagnetic wave and has the characteristics of short wavelength, high energy, strong penetrating power and the like, so that the irradiation of the gamma ray to the quantum dot light-emitting layer can achieve the effect of post annealing, the molecular arrangement is more ordered after the post annealing treatment, the mobility of carriers is improved, and the fluorescence quenching of a device caused by the accumulation of interface charges is avoided; compared with the traditional thermal annealing, the gamma-ray annealing mechanism has particularity, not only can achieve the purpose of the traditional annealing, but also can improve the photoelectric property of the quantum dot device, and has beneficial effect on the precision of the QLED performance test.
Drawings
Fig. 1 is a flowchart of a preferred embodiment of a method for manufacturing a quantum dot light emitting diode according to the present invention.
Fig. 2 is a schematic structural diagram of a quantum dot light emitting diode with a front-mounted structure according to a preferred embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a quantum dot light emitting diode with an inverted structure according to a preferred embodiment of the present invention.
Fig. 4 is a graph comparing the current efficiency test results of the quantum dot light emitting diodes manufactured in example 1 and comparative example 1.
Fig. 5 is a schematic view showing a lifetime curve and a forward aging interval of the quantum dot light emitting diode manufactured in comparative example 1.
Fig. 6 is a schematic diagram of the lifetime curve and the forward aging interval of the quantum dot light emitting diode manufactured in example 1.
Detailed Description
The invention provides a quantum dot light-emitting diode and a preparation method thereof, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Normally, electron-hole pairs (excitons) generated within a quantum dot should first relax within the band and then recombine at the band edge, releasing a photon. If the quantum dot light emitting layer is defective, the exciton may relax to the defect level. Due to the addition of other relaxation and recombination paths, the decay kinetics of excitons change, and the luminescent capability of a defective quantum dot luminescent layer is weakened due to the fact that a defect state usually has a non-radiative transition with a high probability, so that the photoelectric performance of the quantum dot luminescent diode is poor.
Based on this, the present invention provides a method for preparing a quantum dot light emitting diode, as shown in fig. 1, which comprises the steps of:
s10, depositing a quantum dot solution on the prefabricated device, wherein the quantum dot solution comprises an organic solvent and a quantum dot material dispersed in the organic solvent;
and S20, performing irradiation treatment on the quantum dot solution by adopting gamma rays, and forming a quantum dot light-emitting layer on the prefabricated device.
The quantum dot light-emitting layer is formed by carrying out gamma ray irradiation treatment on the quantum dot solution deposited on the prefabricated device, so that the photoelectric performance of the quantum light-emitting diode can be effectively improved, and the action mechanism is as follows:
the gamma ray is actually an electromagnetic wave with extremely short wavelength and large energy, and the gamma ray is partially converted into heat energy to raise the temperature of an object, so that the irradiation treatment of the gamma ray on the quantum dot solution can achieve the effect of post-annealing, the arrangement of quantum dots in the quantum dot light-emitting layer can be more ordered after the post-annealing treatment, and the carrier mobility of the quantum dot light-emitting layer is improved.
The heating rate of gamma rays is high when the gamma rays irradiate the material, compared with conventional thermal annealing, the annealing precision can be more accurately controlled, the negative influence on the quantum dot light-emitting layer with high heat sensitivity is reduced, meanwhile, the residual organic solvent in the quantum dot light-emitting layer can be more fully removed due to the high penetrability of the gamma rays, and the light-emitting efficiency of the quantum dot light-emitting layer is improved;
meanwhile, when the gamma rays are adopted to irradiate the quantum dot solution, photons can excite electrons, the electrons in the quantum dot solution can fill the defect state of the film layer, the coulomb efficiency is improved, the luminous efficiency of the quantum dot luminous layer is beneficially influenced, and therefore the photoelectric performance of the quantum dot luminous diode is improved.
Further, in the performance test process of the quantum dot light emitting diode, it takes a long time for the state of the device to reach the optimal value after the power supply is driven, but the longer the time for the state of the device to reach the optimal value is, the greater the damage to the device is, so how to accelerate aging of the device before the life test to shorten the time for the state of the device to reach the optimal value is also an important research topic.
In this embodiment, the precision of the performance test of the QLED can be effectively improved by performing gamma ray irradiation treatment on the quantum dot solution, and the action mechanism is as follows:
the gamma ray is essentially electromagnetic wave with short wavelength, when the gamma ray passes through the quantum dot light-emitting layer, a photoelectric effect can occur when the gamma ray interacts with atoms of the quantum dot light-emitting layer, a certain aging effect is achieved on the quantum dot light-emitting layer, but the performance of the quantum dot device after being driven within a certain period of time is in a rising state, and in the process of testing the working life, the larger the rising time and amplitude are, the more obvious the influence on the test is. The gamma-ray irradiation treatment with low intensity in a short time plays a positive aging role for the device, namely, the quantum dot material is excited, the short-time annealing process plays an equivalent role of electrifying and aging for a longer and proper time, the performance test time can be shortened, and therefore the efficiency of the device performance test can be effectively improved.
In some embodiments, in the step of subjecting the quantum dot solution to irradiation treatment with gamma rays, the irradiation intensity is 5 to 15 Gy.
In this embodiment, if the irradiation intensity is less than 5Gy, the ideal annealing degree cannot be achieved, and the device performance is affected; if the irradiation intensity is higher than 15Gy, the high-energy gamma rays may damage the quantum dot structure, resulting in fluorescence quenching.
In some embodiments, in the step of performing the irradiation treatment on the quantum dot solution by using the gamma ray, the irradiation dose rate is 1 to 1.5 Gy/s.
In this embodiment, if the irradiation dose rate is less than 1Gy/s, the annealing efficiency is slow; if the irradiation dose rate is more than 1.5Gy/s, the energy is increased too fast, the quantum dot structure is easily damaged, and fluorescence quenching is caused.
In some embodiments, the quantum dot material is a direct bandgap compound semiconductor with light emitting capabilities, including but not limited to one or more of group II-VI compounds, group III-V compounds, group II-V compounds, group III-VI compounds, group IV-VI compounds, group I-III-VI compounds, group II-IV-VI compounds, or group IV elements.
In particular, the semiconductor materials used in the quantum dot light emitting layer of the present embodiment include, but are 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, or quaternary II-VI compounds; nanocrystals of group III-V semiconductors such as GaP, GaAs, InP, InAs and other binary, ternary, quaternary III-V compounds; the semiconductor material for electroluminescence is not limited to group II-V compounds, group III-VI compounds, group IV-VI compounds, group I-III-VI compounds, group II-IV-VI compounds, group IV simple substance, and the like.
In some embodiments, the quantum dot material is one of an undoped inorganic perovskite type semiconductor, a doped inorganic perovskite type semiconductor, or an organic-inorganic hybrid perovskite type semiconductor, but is not limited thereto.
Specifically, the structural general formula of the inorganic perovskite type semiconductor is AMY3Wherein A is Cs+Ion, M is a divalent metal cation, including but not limited to Pb2+、Sn2+、Cu2+、Ni2+、Cd2+、Cr2+、Mn2+、Co2+、Fe2+、Ge2+、Yb2+、Eu2+Y is a halide anion, including but not limited to Cl-、Br-、I-(ii) a The structural general formula of the organic-inorganic hybrid perovskite type semiconductor is BMY3Wherein B is an organic amine cation including but not limited to CH3(CH2)n-2NH3 +(n.gtoreq.2) or NH3(CH2)nNH3 2+(n.gtoreq.2). When n is 2, the inorganic metal halide octahedron MY64-The metal cations M are positioned in the center of a halogen octahedron through connection in a roof sharing mode, and the organic amine cations B are filled in gaps among the octahedrons to form an infinitely extending three-dimensional structure; inorganic metal halide octahedron MY connected in a cospun mode when n is more than 264-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 with each other to form a stable two-dimensional layered structure; m is a divalent metal cation, including but not limited to Pb2+、Sn2 +、Cu2+、Ni2+、Cd2+、Cr2+、Mn2+、Co2+、Fe2+、Ge2+、Yb2+、Eu2+(ii) a Y is a halide anion, including but not limited to Cl-、Br-、I-。
In some embodiments, when the manufactured quantum dot light emitting diode is of an upright structure, the substrate includes a substrate, an anode, and a hole functional layer, which are sequentially stacked from bottom to top, as shown in fig. 2, and the manufacturing of the quantum dot light emitting diode includes:
s01, preparing an anode on the substrate;
s02, preparing a hole function layer on the anode;
s03, depositing a quantum dot solution on the hole function layer;
s04, performing irradiation treatment on the quantum dot solution by adopting gamma rays to form a quantum dot light-emitting layer on the hole function layer;
s05, preparing an electronic function layer on the quantum dot light-emitting layer;
s06, preparing a cathode on the electronic function layer, and obtaining the quantum dot light-emitting diode.
In the present embodiment, the hole function layer includes one or more of an electron blocking layer, a hole injection layer, and a hole transport layer, but is not limited thereto; the electron function layer includes one or more of a hole blocking layer, an electron injection layer, and an electron transport layer, but is not limited thereto.
In this embodiment, the preparation method of each layer may 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 continuous ion layer adsorption and reaction method, an anodic oxidation method, an electrolytic deposition method, and a coprecipitation method; the physical method includes, but is not limited to, one or more of solution method (such as spin coating, printing, knife coating, dip-coating, dipping, spraying, roll coating, casting, slit coating, or bar coating), evaporation method (such as thermal evaporation, electron beam evaporation, magnetron sputtering, or multi-arc ion plating), deposition method (such as physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.).
In other embodiments, when the manufactured quantum dot light emitting diode has an inverted structure, the substrate includes a substrate, a cathode, and an electronic functional layer, which are sequentially stacked from bottom to top, as shown in fig. 2, and the manufacturing of the quantum dot light emitting diode includes:
s100, preparing a cathode on the substrate;
s200, preparing an electronic functional layer on the cathode;
s300, depositing a quantum dot solution on the electronic function layer;
s400, carrying out irradiation treatment on the quantum dot solution by adopting gamma rays, and forming a quantum dot light-emitting layer on the electronic function layer;
s500, preparing a hole function layer on the quantum dot light-emitting layer;
s600, preparing an anode on the hole function layer to obtain the quantum dot light-emitting diode.
In the present embodiment, the hole function layer includes one or more of an electron blocking layer, a hole injection layer, and a hole transport layer, but is not limited thereto; the electron function layer includes one or more of a hole blocking layer, an electron injection layer, and an electron transport layer, but is not limited thereto.
In this embodiment, the preparation method of each layer may 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 continuous ion layer adsorption and reaction method, an anodic oxidation method, an electrolytic deposition method, and a coprecipitation method; the physical method includes, but is not limited to, one or more of solution method (such as spin coating, printing, knife coating, dip-coating, dipping, spraying, roll coating, casting, slit coating, or bar coating), evaporation method (such as thermal evaporation, electron beam evaporation, magnetron sputtering, or multi-arc ion plating), deposition method (such as physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.).
In some embodiments, a quantum dot light emitting diode is also provided, which comprises a quantum dot light emitting layer prepared by subjecting a quantum dot solution to gamma ray irradiation treatment.
In the embodiment, the quantum dot light-emitting layer is formed by performing gamma ray irradiation treatment on the quantum dot solution, so that the photoelectric performance of the quantum light-emitting diode can be effectively improved, and the action mechanism is as follows:
gamma-rays are actually electromagnetic waves with extremely short wavelength and large energy, and the gamma-rays are partially converted into heat energy to increase the temperature of an object, so that the gamma-rays used in the embodiment can achieve the effect of post annealing after the gamma-rays are used for irradiating the quantum dot solution, the quantum dots in the quantum dot light emitting layer can be arranged more orderly after the post annealing treatment, and the carrier mobility of the quantum dot light emitting layer is improved.
The heating rate of gamma rays is high when the gamma rays irradiate the material, compared with conventional thermal annealing, the annealing precision can be more accurately controlled, the negative influence on the quantum dot light-emitting layer with high heat sensitivity is reduced, meanwhile, the residual organic solvent in the quantum dot light-emitting layer can be more fully removed due to the high penetrability of the gamma rays, and the light-emitting efficiency of the quantum dot light-emitting layer is improved;
meanwhile, when the gamma rays are adopted to irradiate the quantum dot solution, photons can excite electrons, electrons in the quantum dot light-emitting layer can fill in the defect state of the film layer, the coulomb efficiency is improved, the light-emitting efficiency of the quantum dot light-emitting layer is beneficially influenced, and therefore the photoelectric performance of the quantum dot light-emitting diode is improved.
Further, in this embodiment, the precision of the performance test of the QLED can be effectively improved by performing gamma ray irradiation treatment on the quantum dot light emitting layer, and the action mechanism is as follows:
the gamma ray is electromagnetic wave with short wavelength, when the gamma ray passes through the quantum dot luminescent layer, the gamma ray can generate photoelectric effect when interacting with the atoms of the gamma ray, and has certain aging effect on the quantum dot luminescent layer, but the performance of the quantum dot device after being driven is in a rising state within a certain period of time, and in the process of testing the working life, the larger the rising time and amplitude is, the more obvious the influence on the test is. The gamma-ray irradiation treatment with low intensity in a short time plays a positive aging role for the device, namely, the quantum dot material is excited, the short-time annealing process plays an equivalent role of electrifying aging for a longer and proper time, and the precision of device performance test can be effectively improved.
In some specific embodiments, an inverted quantum dot light emitting diode is provided, which includes a substrate, an anode, a hole transport layer, a quantum dot light emitting layer, an electron transport layer, and a cathode, which are stacked in sequence from bottom to top, where the quantum dot light emitting layer is subjected to gamma ray irradiation treatment.
In some specific embodiments, the quantum dot light emitting diode with the inverted structure further 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, wherein the quantum dot light emitting layer is subjected to gamma ray irradiation treatment.
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.
In some embodiments, the hole transport layer material is selected from Poly (9, 9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine) (TFB), Polyvinylcarbazole (PVK), Poly (N, N ' bis (4-butylphenyl) -N, N ' -bis (phenyl) benzidine) (Poly-TPD), Poly (9, 9-dioctylfluorene-CO-bis-N, N-phenyl-1, 4-Phenylenediamine) (PFB), 4', 4 ″ -tris (carbazol-9-yl) triphenylamine (TCTA), 4' -bis (9-Carbazole) Biphenyl (CBP), N ' -diphenyl-N, N ' -bis (3-methylphenyl) -1,1 ' -biphenyl-4, 4' -diamine (TPD), N ' -diphenyl-N, N ' - (1-naphthyl) -1,1 ' -biphenyl-4, 4' -diamine (NPB), but is not limited thereto.
In some embodiments, the electron transport layer is selected from ZnO, TiO, NiO, W2O3、Mo2O3、SnO、ZrO2And Ta2O3But is not limited thereto.
In some embodiments, the cathode may be Au, Ag, Al, Cu, Mo, or an alloy thereof, but is not limited thereto.
In some embodiments, the anode has a thickness of 5 to 120 nm.
In some embodiments, the hole transport layer has a thickness of 30-120 nm.
In some embodiments, the quantum dot light emitting layer has a thickness of 10 to 200 nm.
In some embodiments, the electron transport layer has a thickness of 5 to 100 nm;
in some embodiments, the cathode has a thickness of 5 to 120 nm.
The following is a further explanation of the preparation method and performance of a quantum dot light emitting diode according to the present invention by specific examples:
comparative example 1
A preparation method of a quantum dot light-emitting diode with a positive top emission structure comprises the following steps:
1) and spin-coating PEDOT: PSS, rotation speed of 5000, time of 30 seconds, and subsequent heating at 150 ℃ for 15 minutes;
2) spin coating TFB (8mg/mL), at 3000 rpm for 30 seconds, followed by heating at 80 ℃ for 10 minutes;
3) spin-coating quantum dots (20mg/mL), rotating at 2000 for 30 seconds, and then heating at 80 ℃ for 10 minutes;
4) spin coating ZnO (30mg/mL) at 3000 rpm for 30 seconds, and heating at 80 ℃ for 30 minutes;
5) vacuum degree of not higher than 3y10 by thermal evaporation-4And Pa, evaporating Ag at the speed of 1 angstrom/second for 200 seconds and at the thickness of 20nm to obtain the top-emitting positive quantum dot light-emitting diode.
Example 1
A preparation method of a quantum dot light-emitting diode with a positive top emission structure comprises the following steps:
1) and spin-coating PEDOT: PSS, rotation speed of 5000, time of 30 seconds, and subsequent heating at 150 ℃ for 15 minutes;
2) spin coating TFB (8mg/mL), at 3000 rpm for 30 seconds, followed by heating at 80 ℃ for 10 minutes;
3) spin-coating quantum dots (20mg/mL), rotating speed 2000, time 30 seconds;
4) irradiating the film by using gamma rays, wherein the irradiation intensity is 12Gy, the irradiation dose rate is 1.5Gy/s, and the irradiation time is 8 s;
5) spin coating ZnO (30mg/mL) at 3000 rpm for 30 seconds, and heating at 80 ℃ for 30 minutes;
6) vacuum degree of not higher than 3y10 by thermal evaporation-4And Pa, evaporating Ag at the speed of 1 angstrom/second for 200 seconds and at the thickness of 20nm to obtain the top-emitting positive quantum dot light-emitting diode.
The quantum dot light emitting diodes prepared in example 1 and comparative example 1 were subjected to a current efficiency test, different driving voltages were applied to the quantum dot light emitting diodes, and the current efficiencies thereof were measured, with the results shown in fig. 4. As can be seen from fig. 4, 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 under the same driving voltage.
After the quantum dot light-emitting diode prepared in the comparative example 1 is packaged, the working life data of the device is tested, the working life of the device is determined by using constant current driving of 2mA, the life curve and the schematic diagram of the forward aging interval are shown in FIG. 5, and the working life data are shown in Table 1.
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 by using 2mA constant current driving, and the schematic diagram of the life curve and the forward aging interval thereof is shown in fig. 6, and the working life data is shown in table 1.
Comparing fig. 5 and fig. 6, it can be seen that the brightness increase of the device in comparative example 1 is 5.4h, while the brightness increase section of the device in this example 1 is 2.5h, which shows that the gamma ray irradiation treatment has a positive aging effect on the device, and can effectively improve the efficiency of the device life test. L (cd/m) in Table 12) Represents the maximum luminance of the device; t95(h) indicates that the device is driven at constant current of 2mATime taken for the luminance to decay to 95%; t95 — 1k (h) represents the time required for the luminance to decay to 95% at a luminance of 1000nit for the device. As can be seen by comparing the data in Table 1, the maximum luminance of the quantum dot light emitting diode prepared in this example 1 is 77610cd/m2Is obviously higher than the highest brightness 71030cd/m of the quantum dot light-emitting diode prepared in the comparative example 12(ii) a The time for the quantum dot light-emitting diode prepared in the embodiment 1 to attenuate the brightness to 95% under the constant current drive of 2mA is 10.1 hours, which is obviously longer than the time for the quantum dot light-emitting diode prepared in the comparative example 1 to attenuate the brightness to 95% under the constant current drive of 2mA by 7.3 hours; the time required for the brightness of the quantum dot light emitting diode prepared in example 1 to decay to 95% is 16489 at a brightness of 1000nit, which is significantly higher than the time required for the brightness of the quantum dot light emitting diode prepared in comparative example 1 to decay to 95% of 10251h at a brightness of 1000 nit.
In conclusion, the invention uses the gamma ray annealing mode to anneal the quantum dot solution, the gamma ray is electromagnetic wave with short wavelength, and has the characteristics of short wavelength, high energy, strong penetrating power and the like, so the gamma ray is used to irradiate the quantum dot luminescent layer to play the post-annealing effect, the molecular arrangement is more ordered after the post-annealing treatment, the mobility of the current carrier is improved, and the fluorescence quenching of the device caused by the accumulation of interface charges is avoided; compared with the traditional thermal annealing, the annealing mechanism of the gamma rays has particularity, the purpose which can be achieved by the traditional annealing can be achieved, the photoelectric property of the quantum dot device can be improved, and the accuracy of the QLED performance test is favorably influenced.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. A preparation method of a quantum dot light-emitting diode is characterized by comprising the following steps:
depositing a quantum dot solution on a prefabricated device, wherein the quantum dot solution comprises an organic solvent and a quantum dot material dispersed in the organic solvent;
and irradiating the quantum dot solution by adopting gamma rays to form a quantum dot light-emitting layer on the prefabricated device.
2. The method for manufacturing a quantum dot light-emitting diode according to claim 1, wherein in the step of irradiating the quantum dot solution with gamma rays, the irradiation intensity is 5 to 15 Gy.
3. The method for preparing the quantum dot light-emitting diode according to claim 1, wherein in the step of performing irradiation treatment on the quantum dot solution by using gamma rays, the irradiation dose rate is 1-1.5 Gy/s.
4. The method of claim 1, wherein the quantum dot material is one or more of group II-VI compounds, group III-V compounds, group II-V compounds, group III-VI compounds, group IV-VI compounds, group I-III-VI compounds, group II-IV-VI compounds, or group IV simple substance.
5. The method for preparing a quantum dot light-emitting diode according to claim 4, wherein the quantum dot material is one of an undoped inorganic perovskite type semiconductor, a doped inorganic perovskite type semiconductor or an organic-inorganic hybrid perovskite type semiconductor.
6. The method for preparing the quantum dot light-emitting diode according to claim 1, wherein the prefabricated device comprises a substrate, an anode and a hole functional layer which are sequentially stacked from bottom to top, and the prefabricated preparation comprises the following steps:
preparing an anode on the substrate;
preparing a hole function layer on the anode;
or, the prefabrication comprises a substrate, a cathode and an electronic function layer which are sequentially stacked from bottom to top, and the preparation of the substrate comprises the following steps:
preparing a cathode on the substrate;
an electronically functional layer is prepared on the cathode.
7. The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the irradiation treatment of the quantum dot solution with gamma rays is performed to form a quantum dot light-emitting layer on a substrate, and further comprising the steps of:
preparing a hole function layer on the quantum dot light-emitting layer;
preparing an anode on the hole functional layer to obtain the quantum dot light-emitting diode;
or preparing an electronic function layer on the quantum dot light-emitting layer;
and preparing a cathode on the electronic functional layer to obtain the quantum dot light-emitting diode.
8. The method of any one of claims 6 to 7, wherein the hole-functional layer comprises one or more of an electron blocking layer, a hole injection layer and a hole transport layer.
9. The method for preparing a quantum dot light-emitting diode according to any one of claims 6 to 7, wherein the electron functional layer comprises one or more of a hole blocking layer, an electron injection layer and an electron transport layer.
10. The quantum dot light-emitting diode is characterized by comprising a quantum dot light-emitting layer, wherein the quantum dot light-emitting layer is prepared by carrying out gamma ray irradiation treatment on a quantum dot solution.
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