Bilateral interface modified inverted perovskite quantum dot light-emitting device and preparation method thereof

Abstract

The application discloses a double-side interface modified inverted perovskite quantum dot light-emitting device and a preparation method thereof. The double-side interface modified inverted perovskite quantum dot light-emitting device comprises, from bottom to top, a pretreated transparent conductive substrate, an electron transport layer, a bottom interface modification layer, a perovskite quantum dot light-emitting layer, a top interface modification layer, a hole transport layer and a composite anode layer which are sequentially stacked. The application improves the device performance by introducing the interface modification layer on both sides, wherein the bottom interface modification layer can passivate the surface defects between the electron transport layer and the quantum dot layer, inhibit the degradation of organic cation deprotonization and improve fluorescence quenching; the dense organic network formed by the top interface modification layer fills the interface rough pinholes and prevents the light-emitting layer from being eluted and damaged in the subsequent solution spin coating process due to its orthogonal solvent characteristics. The application effectively improves the interface contact, solves the interface incompatibility and significantly improves the light-emitting efficiency, brightness and running stability of the perovskite quantum dot light-emitting diode.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic materials and devices, specifically to an inverted perovskite quantum dot light-emitting device with dual-sided interface modification and its fabrication method. Background Technology

[0002] Lead halide perovskite quantum dots (LHP-QDs) are considered highly promising luminescent materials for next-generation lighting and high-definition displays due to their superior optical properties, including high fluorescence quantum yield, continuously tunable emission wavelength, multiexciton generation mechanism, and high color purity. In particular, in the device structure design of perovskite light-emitting diodes (Pe-LEDs), the inverted pin structure offers significant commercial advantages in the next-generation display industry due to its perfect compatibility with active matrix panels driven by n-type thin-film transistors (TFTs).

[0003] However, there are some challenges in applying LHP-QDs to the aforementioned LED devices at this stage. In conventional synthesis, in order to maintain the colloidal stability of quantum dots, their surfaces are usually coated with a large number of long-chain insulating organic ligands (such as oleic acid, oleylamine, etc.), which severely hinders the injection and transport of charge carriers. Therefore, current research typically employs short-chain ligands such as inorganic ligand CaBr2 (see "Preparation and Characterization of Nitrogen and Sulfur Doped GreenCarbon Dots with Aggregation-induced Emission. CJL, 44(11): 2002-2010,2023"), very short-chain bidentate ligand FASCN (see patent application No. 202410430242.8), and conjugated or organic ammonium ligands (see "Fluorescence properties and laser-induced enhancement of CsPbBr3 quantum dot with three different ligand amine systems, Opt Mater. ,143, 114254, 2023") for ligand exchange. Although this short-chain ligand compensation strategy improves the conductivity of the film, the short-chain ligands have low steric hindrance and weak bonding with the quantum dot surface, making them prone to detachment during purification or film formation. This leads to irreversible aggregation of the quantum dots, making their physicochemical stability extremely fragile.

[0004] This material fragility caused by short-chain ligand compensation can lead to multiple thin film and interface problems in the actual fabrication and operation of pin-structured devices, specifically manifested in the following ways: (1) Deterioration of the film quality of the light-emitting layer itself: When quantum dots with poor dispersion or aggregation are coated, they will produce extremely high surface roughness and form a large number of micron-sized pinholes inside the film, which will cause serious leakage current and non-radiative recombination quenching of the device under electric drive.

[0005] (2) Chemical Erosion at the Bottom Interface: Inverted pin structures often use ZnO nanocrystals as the bottom electron transport layer. Although ZnO has high electron mobility and high transmittance, its surface is rich in oxygen vacancy defects and strong basic hydroxyl groups (-OH). These basic groups can trigger the deprotonation reaction of organic cations in perovskite materials, accelerating the chemical degradation of quantum dots at the bottom interface and causing fluorescence quenching. Existing research has found that reasonable interface modification layers can resolve the chemical conflicts and are worth learning from.

[0006] (3) Solvent elution at the top interface: In order to achieve low-cost, large-area manufacturing, multi-step wet spin coating process is usually used to prepare devices. When the hole transport layer (such as PEDOT:PSS, Poly-TPD, TFB, NiO, etc.) is spin-coated on the quantum dot layer, the solvent used (such as chlorobenzene, n-heptane, etc.) will cause strong physical impact and solvent erosion to the quantum dot film with weak bonding and poor stability on the lower layer. This serious damage from top to bottom significantly restricts the luminous efficiency and operating life of the device.

[0007] In summary, for perovskite quantum dot systems with short-chain ligand compensation exhibiting poor thermal and chemical stability, conventional structural designs struggle to balance luminescence performance with interface stability. Therefore, designing an effective dual-interface synergistic modification strategy that can overcome the leakage current problem caused by poor film formation due to quantum dot aggregation, while simultaneously blocking chemical erosion at the bottom interface and resisting solvent elution during top coating, remains a critical technological bottleneck to be addressed in the field of perovskite microdisplays. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides an inverted perovskite quantum dot light-emitting device with dual-sided interface modification and its fabrication method.

[0009] The technical solution of this invention to solve the aforementioned technical problem is to provide a method for fabricating an inverted perovskite quantum dot light-emitting device with dual-sided interface modification, characterized in that the method includes the following steps: Step 1: The transparent conductive substrate is ultrasonically cleaned and dried sequentially with deionized water, acetone, anhydrous ethanol and isopropanol, and then subjected to ultraviolet ozone pretreatment to obtain the pretreated transparent conductive substrate. Step 2: In an air atmosphere, spin-coat the electron transport layer dispersion onto the surface of the pretreated transparent conductive substrate obtained in Step 1, and then perform annealing to form an electron transport layer. Step 3: In an inert gas atmosphere, spin-coat the bottom interface modification layer solution onto the surface of the electron transport layer obtained in Step 2, and then perform annealing treatment to form the bottom interface modification layer. Step 4: In an inert gas atmosphere, spin-coat the perovskite quantum dot luminescent layer dispersion onto the surface of the bottom interface modification layer obtained in Step 3. After the dispersant evaporates, a perovskite quantum dot luminescent layer is formed. Step 5: In an inert gas atmosphere, spin-coat the top interface modification layer solution onto the surface of the perovskite quantum dot light-emitting layer obtained in Step 4, and then perform annealing treatment to form the top interface modification layer. Step 6: In an inert gas atmosphere, spin-coat the hole transport layer solution onto the surface of the top interface modification layer obtained in Step 5. After the solvent evaporates, a hole transport layer is formed. Step 7: In a vacuum environment, a buffer layer and a metal top electrode are sequentially deposited on the surface of the hole transport layer obtained in step 6 to form a composite anode layer, thereby obtaining an inverted perovskite quantum dot light-emitting device with double-sided interface modification.

[0010] The technical solution of the present invention to solve the technical problem of the light-emitting device is to provide a method for preparing the double-sided interface modified inverted perovskite quantum dot light-emitting device. The double-sided interface modified inverted perovskite quantum dot light-emitting device is characterized in that the light-emitting device includes a pretreated transparent conductive substrate, an electron transport layer, a bottom interface modification layer, a perovskite quantum dot light-emitting layer, a top interface modification layer, a hole transport layer and a composite anode layer stacked from bottom to top.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention innovatively proposes a dual-interface collaborative modification strategy. The dual-interface collaborative protection design effectively improves interface incompatibility, significantly enhances the luminous efficiency, brightness and operational stability of perovskite quantum dot light-emitting devices, and solves the problems of chemical erosion, solvent damage and morphological leakage in the prior art.

[0012] (2) The synergistic effect mechanism of the present invention is as follows: On the electronic side, the introduction of the bottom interface modification layer significantly improves the surface uniformity of the underlying substrate, providing a smooth and high-quality growth foundation for the luminescent layer. Furthermore, through interaction with hydroxyl and oxygen vacancies on the electron transport layer surface, it eliminates basic non-radiative recombination centers and simultaneously interacts with uncoordinated Pb at the bottom of the perovskite quantum dot luminescent layer. 2+ A strong bond is formed. This in-situ chemical anchoring inhibits the chemical erosion of the organic cations within the perovskite quantum dot luminescent layer by the electron transport layer.

[0013] On the hole side, the top interface modification layer forms a hydrogen bond network by coordinating with the dangling bonds on the quantum dot surface, effectively passivating halogen vacancies. More importantly, this layer, with its excellent orthogonal solvent properties, prevents solvent elution damage during subsequent spin-coating of the hole transport layer. Its dense organic network precisely fills and covers the microscopic rough morphology and pinhole defects on the quantum dot film surface, reducing the defect state density and suppressing ion migration in the working state.

[0014] This dual-sided combined mechanism, which features a flat bottom substrate with chemical corrosion resistance and a top side that fills pinholes and provides physical erosion resistance, successfully locks the quantum dot network, significantly eliminating thin film damage caused by multi-step solution processing and improving the device's luminescence efficiency and long-term stability.

[0015] (3) The bottom interface modification layer of the present invention can passivate the surface defects between the electron transport layer and the perovskite quantum dot light-emitting layer, inhibit the deprotonation degradation of organic cations, and improve fluorescence quenching; the dense organic network formed by the top interface modification layer fills the rough pinholes of the interface, and prevents the elution effect in the subsequent solution spin coating process by virtue of its orthogonal solvent properties.

[0016] (4) Thanks to the synergistic effect of the two-sided interface, compared with the basic device that does not adopt this synergistic structure, the start-up voltage of the device of the present invention is reduced, the maximum external quantum efficiency (EQE) reaches 3%, and the highest electroluminescence brightness is as high as 9600 cd / m². 2 This invention provides a novel technical approach with great commercial potential to overcome the processing bottlenecks of perovskite quantum dot films, laying a solid foundation for realizing low-cost, high-brightness, and long-life perovskite micro-display devices. Attached Figure Description

[0017] Figure 1 This is the energy level design diagram of the inverted perovskite quantum dot light-emitting device according to Embodiment 1 of the present invention; Figure 2 This is a SEM image of the perovskite quantum dot emitting layer in the inverted perovskite quantum dot light-emitting device of Embodiment 1 of the present invention; Figure 3 This is a SEM image of the perovskite quantum dot light-emitting layer in the inverted perovskite quantum dot light-emitting device of Comparative Example 3 of the present invention. Figure 4 The photoluminescence spectra of the inverted perovskite quantum dot emitting layers of Embodiment 1 and Comparative Example 1 of the present invention are shown below. Figure 5 This is a current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Embodiment 1 of the present invention; Figure 6 This is a current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Embodiment 2 of the present invention; Figure 7 This is a current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Embodiment 3 of the present invention; Figure 8 This is a current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Embodiment 4 of the present invention; Figure 9 The current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Comparative Example 1 of the present invention is shown. Figure 10 This is a current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Comparative Example 2 of the present invention. Figure 11 The current density-voltage-brightness characteristic curve of the inverted perovskite quantum dot light-emitting device of Comparative Example 3 of the present invention is shown. Detailed Implementation

[0018] Specific embodiments of the present invention are given below. These specific embodiments are only used to further illustrate the present invention in detail and do not limit the scope of protection of the present invention.

[0019] This invention provides a method for fabricating an inverted perovskite quantum dot light-emitting device with dual-sided interface modification (hereinafter referred to as the method), characterized in that the method includes the following steps: Step 1: The transparent conductive substrate is ultrasonically cleaned and dried sequentially with deionized water, acetone, anhydrous ethanol and isopropanol, and then subjected to ultraviolet ozone pretreatment to obtain the pretreated transparent conductive substrate. Preferably, in step 1, the transparent conductive substrate has sufficient conductivity to transport electrons, and preferably is a material with a low work function, specifically any one of ITO conductive glass, IZO conductive glass, FTO conductive glass, ITO / FTO polyethylene naphthalate flexible substrate or ITO / FTO polyethylene terephthalate flexible substrate (preferably ITO conductive glass).

[0020] Preferably, in step 1, the ultrasonic cleaning and drying process is as follows: the transparent conductive substrate is ultrasonically cleaned with deionized water, acetone and anhydrous ethanol for 10-30 minutes respectively, and then ultrasonically cleaned with isopropanol for 10-50 minutes. The ultrasonic frequency is 28-80 kHz, the temperature is 40-60℃ and the ultrasonic power is 50-600 W. After the process, the transparent conductive substrate is placed in clean isopropanol for storage and later use. When needed, the transparent conductive substrate is removed from the isopropanol and dried with a nitrogen gun to remove the isopropanol from its surface.

[0021] Preferably, in step 1, the ultraviolet ozone pretreatment process is as follows: ultraviolet ozone pretreatment is carried out in an air atmosphere for 10-60 minutes, with a light source power of 10-300W, a temperature of 40-60℃, and an ozone concentration of 50-1000ppm. Preferably, this is carried out in a reaction chamber.

[0022] Step 2: In an air atmosphere, spin-coat the electron transport layer dispersion onto the surface of the pretreated transparent conductive substrate obtained in Step 1, and then perform annealing to form an electron transport layer. Preferably, in step 2, the electron transport layer dispersion is prepared by uniformly dispersing the electron transport layer material in ethanol or deionized water to obtain an electron transport layer dispersion with a concentration of 5~60 mg / mL. Preferably, in step 2, the electron transport layer material is an inorganic metal oxide nanoparticle with a deep highest molecular occupied orbital (HOMO), which can achieve hole blocking and has good electron accepting ability. At the same time, it can effectively transfer electrons under a certain bias voltage. Specifically, it is at least one of zinc oxide (ZnO), tin dioxide (SnO2), or titanium dioxide (TiO2) prepared by atomic layer deposition, magnetron sputtering, or solution spin coating (preferably zinc oxide prepared by solution spin coating).

[0023] Preferably, in step 2, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1500~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 .

[0024] Preferably, in step 2, the annealing process is: annealing at a temperature of 100~600℃ for 10~60min.

[0025] Step 3: In an inert gas atmosphere, spin-coat the bottom interface modification layer solution onto the surface of the electron transport layer obtained in Step 2, and then perform annealing treatment to form the bottom interface modification layer. Preferably, in step 3, the preparation of the bottom interface modification layer solution is as follows: the bottom interface modification layer material is dissolved in toluene to prepare a bottom interface modification layer solution with a concentration of 1~10 mg / mL; Preferably, in step 3, the bottom interface modification layer material is pentaerythritol tetra(3-mercaptopropionate) (PETMP), trimethylolpropane tri(3-mercaptopropionate) (TMPMP), or 1,6-hexanedithiol (preferably PETMP).

[0026] Preferably, in step 3, the spin coating process is as follows: a static spin coating method is adopted, the spin coating speed is 1500~5000 rpm, the spin coating time is 20~60 s, and the acceleration is 500~3000 rpm·s. -1 .

[0027] Preferably, in step 3, the annealing process is: annealing at a temperature of 80~200℃ for 10~60 minutes.

[0028] Preferably, in step 3, the inert gas atmosphere is nitrogen.

[0029] Step 4: In an inert gas atmosphere, spin-coat the perovskite quantum dot luminescent layer dispersion onto the surface of the bottom interface modification layer obtained in Step 3. After the dispersant evaporates, a perovskite quantum dot luminescent layer is formed. Preferably, in step 4, the perovskite quantum dot luminescent layer dispersion is prepared by dispersing the perovskite quantum dot luminescent layer material in a dispersant to obtain a perovskite quantum dot luminescent layer dispersion with a concentration of 5~50 mg / ml. Preferably, in step 4, the perovskite quantum dot luminescent layer material is an organic-inorganic hybrid perovskite quantum dot containing short-chain organic ammonium cationic ligands, preferably PEA. + Modified FAPbBr3; the short-chain organic ammonium cationic ligand is phenylethylammonium (PEA). + ), Butylammonium (BA) + ), propylammonium (PA) + ) or benzyl ammonium (PMA) + The dispersant is a non-polar solvent; the non-polar solvent is at least one of toluene, n-octane, n-heptane, and n-hexane.

[0030] Preferably, in step 4, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1000~4000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~2000 rpm·s. -1 .

[0031] Preferably, in step 4, the dispersant volatilization process is: natural volatilization and drying at room temperature.

[0032] Preferably, in step 4, the perovskite quantum dots containing short-chain organic ammonium cationic ligands are prepared as follows: First, dissolve 100 mg of FABr, 150 mg of PbBr2, and 405 mg of PEABr in 1 ml of N,N-dimethylformamide (DMF) to prepare 0.8 M FABr, 0.4 M PbBr2, and 2 M PEABr solutions, respectively. Then, mix 150 μL of FABr solution, 150 μL of PbBr2 solution, and 12.5 μL of PEA-Br solution thoroughly to obtain a mixed precursor solution, ensuring that the molar ratio of PEABr is consistent with that of PEABr. + :Pb 2+=0.2:1; The mixed precursor solution was rapidly added to a vigorously stirred nonpolar solvent mixture consisting of 5 mL toluene, 2 mL 1-butanol, 150 μL OA, and 25 μL OTAm. The mixture was then reacted for 1 min to obtain a bright green Pe QDs crude solution. The resulting QDs crude solution was then added to three times its volume of ultra-dry acetonitrile and centrifuged at 10000 rpm for 5 min. The precipitated QDs were redispersed in 1 mL of octane and centrifuged at 3000 rpm for 3 min to remove insoluble particles. The supernatant was collected and filtered through a 0.22 μm organic phase needle filter to obtain PEA. + Modified FAPbBr3 perovskite quantum dot ink; all synthesis and post-purification processes were carried out at room temperature and in air.

[0033] Step 5: In an inert gas atmosphere, spin-coat the top interface modification layer solution onto the surface of the perovskite quantum dot light-emitting layer obtained in Step 4, and then perform annealing treatment to form a dense top interface modification layer. Preferably, in step 5, the preparation of the top interface modification layer solution is as follows: the top interface modification layer material is dissolved in an alcohol orthogonal solvent that does not dissolve the perovskite quantum dot light-emitting layer to prepare a top interface modification layer solution with a concentration of 0.5~10 mg / mL. Preferably, in step 5, the top interface modification layer material is polyvinylpyrrolidone (PVP), poly(2-ethyl-2-oxazoline) (PEOX), polyvinylcaprolactam (PVCap), or cellulose acetate (CA) (preferably PVP, whose lactam groups have both strong hydrogen bonding ability and strong intermolecular dipole interaction, and can form a robust physical barrier during annealing), with a weight-average molecular weight of 10,000 to 1,500,000; the alcohol orthogonal solvent is at least one of isopropanol, ethanol, and n-butanol.

[0034] Preferably, in step 5, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1500~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 .

[0035] Preferably, in step 5, the annealing process is: annealing at a temperature of 80~200℃ for 5~30 minutes.

[0036] Step 6: In an inert gas atmosphere, spin-coat the hole transport layer solution onto the surface of the top interface modification layer obtained in Step 5. After the solvent evaporates, a hole transport layer is formed. Preferably, in step 6, the hole transport layer solution is prepared by dissolving the hole transport layer material in a non-polar or weakly polar solvent to prepare a hole transport layer solution with a concentration of 5~30 mg / mL. Preferably, in step 6, the hole transport layer material has a shallow highest molecular occupied orbital (HOMO) and high hole mobility, specifically poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)] (TFB), polyvinylcarbazole (PVK), or poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD) (preferably TFB); the nonpolar or weakly polar solvent is at least one of chlorobenzene, toluene, and xylene.

[0037] Preferably, in step 6, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 2000~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 .

[0038] Preferably, in step 6, the dispersant evaporation process is: natural evaporation and drying at room temperature.

[0039] Preferably, steps 2 through 6 all employ the solution spin coating method.

[0040] Step 7: In a vacuum environment, a buffer layer and a metal top electrode are sequentially deposited on the surface of the hole transport layer obtained in step 6 to form a composite anode layer, thereby obtaining an inverted perovskite quantum dot light-emitting device with double-sided interface modification.

[0041] Preferably, in step 7, the evaporation conditions are: the vacuum level in the vacuum chamber is less than 1×10⁻⁶. -3 Pa; the evaporation rate of the buffer layer is 0.1~1 Å / s; the evaporation rate of the metal top electrode is 0.5~2.5 Å / s.

[0042] Preferably, in step 7, the material of the buffer layer has a high work function, approximately between -5.0 eV and -5.5 eV. Its conduction band bottom is aligned with the HOMO level of commonly used organic hole transport layers (such as TFB and Poly-TPD). Under the influence of an electric field, electrons in the hole transport layer are more easily extracted, thus achieving the equivalent purpose of hole injection. Specifically, it is molybdenum oxide (MoO3), vanadium oxide (V2O5), tungsten oxide (WO3), or nickel oxide (NiO2). x The top metal electrode is made of aluminum, silver, or gold; the preferred combination is MoO3 / Al, as MoO3 is a strong p-type metal oxide with a very deep work function (~-5.3eV), which can improve hole injection.

[0043] The present invention also provides a method for preparing a double-sided interface modified inverted perovskite quantum dot light-emitting device. The double-sided interface modified inverted perovskite quantum dot light-emitting device (hereinafter referred to as the light-emitting device) is characterized in that the light-emitting device includes a pretreated transparent conductive substrate, an electron transport layer, a bottom interface modification layer, a perovskite quantum dot light-emitting layer, a top interface modification layer, a hole transport layer and a composite anode layer stacked from bottom to top.

[0044] Preferably, the bottom interface modification layer is an organic molecular layer containing polythiol groups, which has a coordination bond structure with both the electron transport layer and the perovskite quantum dot emitting layer. On the one hand, the thiol groups in the organic molecular layer can form chemical bonds with metal ions on the surface of the electron transport layer, and at the same time interact with hydroxyl groups and oxygen vacancies, passivating surface defects of the electron transport layer and improving its morphology. On the other hand, it can interact with uncoordinated Pb in the perovskite quantum dot emitting layer. 2+ It forms coordination bonds and passivates halogen defects.

[0045] Preferably, the top interface modification layer is an organic polymer with orthogonal solvent properties and carbonyl functional groups. It is a polymer film that can be uniformly spread on the perovskite quantum dot light-emitting layer and form a dense network structure. At the same time, it must also satisfy the solvent orthogonality with the hole transport layer material to prevent solvent elution and damage during subsequent spin coating of functional layers.

[0046] Preferably, the composite anode layer includes a metal top electrode with sufficient conductivity to transport holes to the hole transport layer and a buffer layer.

[0047] Preferably, the device emits light when driven by an external power supply.

[0048] Preferably, the thickness of the pretreated transparent conductive substrate is 10~300nm and the resistance is 10~150Ω; the thickness of the electron transport layer is 5~100nm, the thickness of the bottom interface modification layer is 0.5~20nm, the thickness of the perovskite quantum dot luminescent layer is 5~100nm, the thickness of the top interface modification layer is 0.5~20nm, the thickness of the hole transport layer is 5~100nm, and the thickness of the composite anode layer is 20~2000nm.

[0049] Example 1: (1) The commercially etched 1.5cm×1.5cm ITO glass was subjected to the following ultrasonic cleaning treatment: the ITO glass was ultrasonically cleaned for 15min each with deionized water, acetone and anhydrous ethanol, and then ultrasonically cleaned for 30min with isopropanol. The ultrasonic frequency was 53kHz, the ultrasonic temperature was set to 25℃ and the ultrasonic power was 250W. Then the surface was dried with a nitrogen gun to remove the isopropanol on the surface. Then the ITO glass was subjected to ultraviolet ozone pretreatment for 30min in an air atmosphere. The light source power was 28W, the working temperature in the reaction chamber was 50℃ and the ozone concentration was 200~500ppm. (2) Disperse ZnO nanoparticles in ethanol to prepare an electron transport layer dispersion with a concentration of 25 mg / ml; then spin-coat 70 μL of the electron transport layer dispersion onto the surface of the pretreated transparent conductive substrate from step (1) at a speed of 5000 rpm for 25 s and an acceleration of 500 rpm·s. -1 Then anneal at 200℃ for 20 minutes to form an electron transport layer; (3) In a glove box containing an inert gas atmosphere, take 70 μL of PETMP chlorobenzene solution with a concentration of 2 mg / ml and spin-coat it statically onto the electron transport layer of step (2) at a spin-coating speed of 2500 rpm for 30 s and an acceleration of 500 rpm·s. -1 Then, annealing is performed at 120℃ for 20 minutes to form a bottom interface modification layer. (4) Take 20 μL of a solution containing 20 mg / ml of PEA. + The modified FAPbBr3 perovskite quantum dot-octane dispersion was spin-coated onto the bottom interface modification layer of step (3) at a spin-coating speed of 1500 rpm and a spin-coating time of 30 s. -1 The acceleration is used to dynamically spin-coat the material, and then it is allowed to dry naturally at room temperature to form a perovskite quantum dot luminescent layer. (5) Dissolve 20 mg of PVP with a weight-average molecular weight of 1,300,000 in 10 ml of anhydrous isopropanol to prepare a PVP-isopropanol solution with a concentration of 2 mg / ml; then take 70 μL of the PVP-isopropanol solution and spin-coat it onto the perovskite quantum dot light-emitting layer of step (4) at a speed of 3000 rpm for 30 s and an acceleration of 1000 rpm·s. -1 Then anneal at 100℃ for 6 minutes to form a dense top interface modification layer; (6) Dissolve 100 mg of TFB with an average molecular weight of 30,000 in 10 ml of chlorobenzene to prepare a TFB chlorobenzene solution with a concentration of 10 mg / ml; then take 50 μL of the TFB chlorobenzene solution and spin-coat it onto the top interface modification layer of step (5) at a speed of 3000 rpm for 30 s with an acceleration of 1000 rpm·s. -1 After the solvent evaporates and dries naturally at room temperature, a hole transport layer is formed. (7) In the vacuum evaporation chamber, a buffer layer and a metal top electrode are sequentially evaporated on the surface of the hole transport layer obtained in step (6) to prepare a composite anode layer. The evaporation rate and thickness are monitored by a film thickness gauge to obtain an inverted perovskite quantum dot light-emitting device with double-sided interface modification. The vacuum degree in the vacuum chamber is less than 1×10 -3 Pa; the evaporation rate of the buffer layer material MoO3 is 0.5 Å / s, and the evaporation rate of the metal top electrode aluminum is 1.5 Å / s.

[0050] The structure of the light-emitting device is: ITO / ZnO (20nm) / PETMP (10nm) / FAPbBr3-PEA (50nm) / PVP (5nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0051] The current-voltage-brightness characteristics of the device were tested, as well as the emission spectrum parameters of the device.

[0052] Depend on Figure 1 As can be seen, the electroluminescence principle of the inverted perovskite quantum dot light-emitting device is as follows: holes and electrons enter the device from the positive and negative poles of the light-emitting diode, respectively, and are conducted to the perovskite quantum dot light-emitting layer through the charge carrier transport layer. Finally, the two types of charge carriers converge and combine to form excitons, and the excitons undergo radiative recombination in the perovskite quantum dot light-emitting layer to emit light.

[0053] Due to the synergistic modification effect of the bottom interface modification layer PETMP and the top interface modification layer PVP film, the perovskite quantum dot luminescent layer exhibits good film formation properties and surface morphology. Figure 2 As can be seen, the bottom interface modification layer PETMP significantly improves the surface uniformity of the substrate, providing a smooth foundation for the preparation of high-quality perovskite quantum dot films. The dense PVP organic network on the top layer fills and covers the microscopic roughness of the quantum dot film surface, with only some pinhole-sized defects. The dual-interface synergistic modification strategy of this invention can effectively compensate for the film formation defects induced by multi-step solution spin coating at the physical level, significantly blocking leakage paths and laying a key structural foundation for realizing efficient and stable electroluminescent devices.

[0054] Depend on Figure 5It can be seen that this structure of visible-light green-emitting inverted perovskite quantum dot light-emitting device can achieve a low turn-on voltage of 3.5V, and reaches a maximum brightness of 9600 cd / m² at a driving voltage of 6.5V. 2 At maximum brightness, the corresponding external quantum efficiency is 3%.

[0055] Example 2: This embodiment is exactly the same as embodiment 1, except that the annealing temperature of PETMP in step (3) is 80°C.

[0056] The structure of the light-emitting device is: ITO / ZnO (20nm) / PETMP (10nm) / FAPbBr3 (50nm) / PVP (5nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0057] Depend on Figure 6 It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 4V, and the maximum brightness of 3400 cd / m² is achieved at a driving voltage of 5.5V. 2 The external quantum efficiency at maximum brightness is 0.3%.

[0058] Example 3: This embodiment is exactly the same as Embodiment 1, except that: in step (5), a PVP-isopropanol solution with a concentration of 4 mg / ml is prepared.

[0059] The structure of the light-emitting device is: ITO / ZnO (20nm) / PETMP (10nm) / FAPbBr3 (50nm) / PVP (10nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0060] Depend on Figure 7 It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 4V, and the maximum brightness of 1030 cd / m² is achieved at a driving voltage of 6.5V. 2 The external quantum efficiency at maximum brightness is 0.6%.

[0061] Example 4: This embodiment is exactly the same as embodiment 1, except that the annealing temperature of the top interface modification layer in step (5) is 150°C.

[0062] The structure of the light-emitting device is: ITO / ZnO (20nm) / PETMP (10nm) / FAPbBr3 (50nm) / PVP (5nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0063] Depend on Figure 8It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 5V, and the maximum brightness of 610 cd / m² is achieved at a driving voltage of 8V. 2 The external quantum efficiency at maximum brightness is 0.1%.

[0064] Comparative Example 1: This comparative example is exactly the same as Example 1, except that the top interface modification layer of step (5) was not prepared on the device.

[0065] The structure of the light-emitting device is: ITO / ZnO (20nm) / PETMP (10nm) / FAPbBr3 (50nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0066] Depend on Figure 4 It can be seen that the PL intensity of the perovskite quantum dot luminescent layer modified with PVP is higher. The annealed PVP layer, with its excellent orthogonal solvent properties, forms a strong physical barrier, effectively preventing the elution and damage of chlorobenzene solvent during subsequent spin coating of TFB.

[0067] Depend on Figure 9 It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 3.5V, and the maximum brightness of 419 cd / m² is achieved at a driving voltage of 6V. 2 The external quantum efficiency at maximum brightness is 0.17%.

[0068] Comparative Example 2: This comparative example is exactly the same as Example 1, except that the bottom interface modification layer of step (3) was not prepared on the device.

[0069] The structure of the light-emitting device is: ITO / ZnO (20nm) / FAPbBr3 (50nm) / PVP (5nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0070] Depend on Figure 10 It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 4.5V, and the maximum luminance of 902 cd / m² is achieved at a driving voltage of 7V. 2 The external quantum efficiency at maximum brightness is 0.05%.

[0071] Comparative Example 3: This comparative example is exactly the same as Example 1, except that the device was not treated with the bottom interface modification layer in step (3), nor was the top interface modification layer in step (5).

[0072] The structure of the light-emitting device is: ITO / ZnO (20nm) / FAPbBr3 (50nm) / TFB (25nm) / MoO3 (8nm) / Al (100nm).

[0073] Depend on Figure 3 It can be seen that in devices without the introduction of a double-sided interface modification layer, the surface morphology of the perovskite quantum dot film exhibits significant roughness and discontinuity, with the quantum dots showing obvious island-like agglomeration distribution characteristics. This loose and uneven film structure not only reduces the coverage of the light-emitting layer, but also easily forms through leakage channels during subsequent electrode deposition and charge injection, leading to a decrease in the device's shunt resistance. This is the morphological root cause of severe leakage current and non-radiative recombination quenching.

[0074] Depend on Figure 11 It can be seen that the turn-on voltage of this inverted perovskite quantum dot light-emitting device is 4.5V, and the maximum brightness of 150 cd / m² is achieved at a driving voltage of 6.5V. 2 The external quantum efficiency at maximum brightness is 0.01%.

[0075] The multi-layer synergistic structure of this invention is perfectly compatible with low-cost multi-step solution processing technology and inverted device architecture. This strategy not only provides a scientific solution to overcome the bottleneck of poor stability and easy leakage of short-chain ligand perovskite quantum dots, but also shows excellent process fault tolerance and device uniformity. It lays a solid technical foundation for the future development of large-area, high-brightness, and long-life perovskite micro-displays and solid-state lighting devices, and has extremely high industrial application prospects.

[0076] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A method for fabricating an inverted perovskite quantum dot light-emitting device with dual-sided interface modification, characterized in that, The method includes the following steps: Step 1: The transparent conductive substrate is ultrasonically cleaned and dried sequentially with deionized water, acetone, anhydrous ethanol and isopropanol, and then subjected to ultraviolet ozone pretreatment to obtain the pretreated transparent conductive substrate. Step 2: In an air atmosphere, spin-coat the electron transport layer dispersion onto the surface of the pretreated transparent conductive substrate obtained in Step 1, and then perform annealing to form an electron transport layer. Step 3: In an inert gas atmosphere, spin-coat the bottom interface modification layer solution onto the surface of the electron transport layer obtained in Step 2, and then perform annealing treatment to form the bottom interface modification layer. Step 4: In an inert gas atmosphere, spin-coat the perovskite quantum dot luminescent layer dispersion onto the surface of the bottom interface modification layer obtained in Step 3. After the dispersant evaporates, a perovskite quantum dot luminescent layer is formed. Step 5: In an inert gas atmosphere, spin-coat the top interface modification layer solution onto the surface of the perovskite quantum dot light-emitting layer obtained in Step 4, and then perform annealing treatment to form the top interface modification layer. Step 6: In an inert gas atmosphere, spin-coat the hole transport layer solution onto the surface of the top interface modification layer obtained in Step 5. After the solvent evaporates, a hole transport layer is formed. Step 7: In a vacuum environment, a buffer layer and a metal top electrode are sequentially deposited on the surface of the hole transport layer obtained in step 6 to form a composite anode layer, thereby obtaining an inverted perovskite quantum dot light-emitting device with double-sided interface modification.

2. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 1, the transparent conductive substrate is any one of ITO conductive glass, IZO conductive glass, FTO conductive glass, ITO / FTO polyethylene naphthalate flexible substrate, or ITO / FTO polyethylene terephthalate flexible substrate. In step 1, the ultrasonic cleaning and drying process is as follows: the transparent conductive substrate is ultrasonically cleaned with deionized water, acetone, and anhydrous ethanol for 10-30 minutes each, and then ultrasonically cleaned with isopropanol for 10-50 minutes. The ultrasonic frequency is 28-80 kHz, the temperature is 40-60℃, and the ultrasonic power is 50-600 W. After the process, the transparent conductive substrate is placed in clean isopropanol for storage and later use. When needed, the transparent conductive substrate is removed from the isopropanol and dried with a nitrogen gun to remove the isopropanol from its surface. In step 1, the ultraviolet ozone pretreatment process is as follows: ultraviolet ozone pretreatment is carried out in an air atmosphere for 10~60 minutes, with a light source power of 10~300W, a temperature of 40~60℃, and an ozone concentration of 50~1000ppm.

3. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 2, the electron transport layer dispersion is prepared by uniformly dispersing the electron transport layer material in ethanol or deionized water to obtain an electron transport layer dispersion with a concentration of 5~60 mg / mL. In step 2, the electron transport layer material is at least one of zinc oxide, tin dioxide, or titanium dioxide; In step 2, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1500~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 ; In step 2, the annealing process is: annealing at 100~600℃ for 10~60min.

4. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 3, the preparation of the bottom interface modification layer solution is as follows: the bottom interface modification layer material is dissolved in toluene to prepare a bottom interface modification layer solution with a concentration of 1~10 mg / mL. In step 3, the bottom interface modification layer material is pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), or 1,6-hexanedithiol. In step 3, the spin coating process is as follows: a static spin coating method is used, with a spin coating speed of 1500~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 ; In step 3, the annealing process is as follows: annealing at 80~200℃ for 10~60min; In step 3, the inert gas atmosphere is nitrogen.

5. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 4, the perovskite quantum dot luminescent layer dispersion is prepared by dispersing the perovskite quantum dot luminescent layer material in a dispersant to obtain a perovskite quantum dot luminescent layer dispersion with a concentration of 5~50 mg / ml. In step 4, the perovskite quantum dot luminescent layer material is an organic-inorganic hybrid perovskite quantum dot containing a short-chain organic ammonium cationic ligand; the short-chain organic ammonium cationic ligand is phenylethylammonium, butylammonium, propylammonium, or benzylammonium; the dispersant is a non-polar solvent; the non-polar solvent is at least one of toluene, n-octane, n-heptane, and n-hexane; In step 4, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1000~4000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~2000 rpm·s. -1 ; In step 4, the dispersant evaporation process is: natural evaporation and drying at room temperature.

6. The method for fabricating the inverted perovskite quantum dot light-emitting device with dual-sided interface modification according to claim 1, characterized in that, In step 5, the preparation of the top interface modification layer solution is as follows: the top interface modification layer material is dissolved in an alcohol orthogonal solvent that does not dissolve the perovskite quantum dot light-emitting layer to prepare a top interface modification layer solution with a concentration of 0.5~10 mg / mL. In step 5, the top interface modification layer material is polyvinylpyrrolidone, poly(2-ethyl-2-oxazoline), polyvinylcaprolactam, or cellulose acetate, with a weight-average molecular weight of 10,000 to 1,500,000; the alcohol orthogonal solvent is at least one of isopropanol, ethanol, and n-butanol. In step 5, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 1500~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 ; In step 5, the annealing process is: annealing at 80~200℃ for 5~30 minutes.

7. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 6, the hole transport layer solution is prepared by dissolving the hole transport layer material in a non-polar or weakly polar solvent to prepare a hole transport layer solution with a concentration of 5~30 mg / mL. In step 6, the hole transport layer material is poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)], polyvinylcarbazole, or poly[bis(4-phenyl)(4-butylphenyl)amine]; the nonpolar or weakly polar solvent is at least one of chlorobenzene, toluene, and xylene; In step 6, the spin coating process is as follows: a dynamic spin coating method is adopted, with a spin coating speed of 2000~5000 rpm, a spin coating time of 20~60 s, and an acceleration of 500~3000 rpm·s. -1 ; In step 6, the dispersant evaporation process is: natural evaporation and drying at room temperature.

8. The method for fabricating the inverted perovskite quantum dot light-emitting device with double-sided interface modification according to claim 1, characterized in that, In step 7, the conditions for vapor deposition are: the vacuum level inside the vacuum chamber is less than 1×10⁻⁶. -3 Pa; the evaporation rate of the buffer layer is 0.1~1 Å / s; the evaporation rate of the metal top electrode is 0.5~2.5 Å / s; In step 7, the material of the buffer layer is molybdenum oxide, vanadium oxide, tungsten oxide, or nickel oxide; the metal top electrode is aluminum, silver, or gold.

9. A method for fabricating an inverted perovskite quantum dot light-emitting device with double-sided interface modification according to any one of claims 1-8, characterized in that, The light-emitting device comprises, from bottom to top, a pretreated transparent conductive substrate, an electron transport layer, a bottom interface modification layer, a perovskite quantum dot light-emitting layer, a top interface modification layer, a hole transport layer, and a composite anode layer, which are stacked sequentially.

10. The inverted perovskite quantum dot light-emitting device with dual-sided interface modification according to claim 9, characterized in that, The thickness of the pretreated transparent conductive substrate is 10~300nm and the resistance is 10~150Ω; the thickness of the electron transport layer is 5~100nm, the thickness of the bottom interface modification layer is 0.5~20nm, the thickness of the perovskite quantum dot luminescent layer is 5~100nm, the thickness of the top interface modification layer is 0.5~20nm, the thickness of the hole transport layer is 5~100nm, and the thickness of the composite anode layer is 20~2000nm.

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