Method for preparing organic-inorganic antimony halide light emitting diode through interface optimization

Abstract

The invention discloses a method for preparing an organic-inorganic antimony halide light-emitting diode through interface optimization, and belongs to the technical field of semiconductor light-emitting devices. The key of interface optimization is that a pi-pi stacked structure is formed between the organic-inorganic antimony halide light-emitting layer and the organic electron transport layer interface. The core action mechanism is that non-covalent pi-pi stacking interaction is generated between a carbazole functional group in antimony halide and a pi conjugated aromatic ring in the electron transport layer. The interaction can construct a high-efficiency charge transfer channel on the molecular scale, and the electron transfer efficiency at the interface of the light-emitting layer / electron transfer layer is remarkably improved. The maximum external quantum efficiency of the prepared organic-inorganic antimony halide light-emitting diode can reach 19.4%, and the half-life period can reach 10190 minutes.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor light-emitting diodes, and particularly relates to a method for promoting the formation of face-to-face stacking between organic ligands and aromatic structures in an organic electron transport layer by introducing a carbazole conjugated group into the organic ligands, thereby generating π-π interaction and realizing the improvement of charge transport performance of organic-inorganic hybrid antimony halide light-emitting diodes. TECHNICAL BACKGROUND As an environmentally friendly, highly efficient and structure-tunable lead-free luminescent material, organic-inorganic hybrid antimony halide exhibits great application potential in the field of light-emitting diodes (LEDs). This kind of material combines the excellent semiconductor properties of inorganic luminescent units with the flexible structure tunability of organic components, and is considered as one of the ideal candidate materials for the next generation of LEDs. At the same time, due to its significant quantum confinement effect and strong electron-phonon coupling, this kind of material can achieve a photoluminescence quantum yield close to 100% and extremely low self-absorption effect, making it have important development prospects in the fields of display and solid-state lighting.

[0002] However, this kind of material still faces key challenges in device preparation. For example, the commonly used organic ligands are mostly cations with large steric hindrance and strong insulating properties, which easily lead to high defect density, poor conductivity and unbalanced carrier injection of antimony halide thin films, limiting the further improvement of device performance. Therefore, the research community has proposed various material optimization strategies such as aggregation-induced emission regulation, host-guest system structure design, and introduction of semiconductor-type cations. For example, Lin Haoran et al. (Small 20, 2403788 (2024)) significantly improved the fluorescence quantum yield of antimony halide thin films through the synergistic regulation of aggregation-induced emission mechanism and halogen substitution; Chen Zhongning's group (Angew. Chem. 134, e202113450 (2022)) effectively improved the film morphology and promoted the charge transport by introducing organic host materials; Ma Biwu et al. (Adv. Mater. 35, 2209417 (2023)) further integrated semiconductor groups in the organic ligands, simultaneously improving the conductivity and energy level matching of the thin film.

[0003] With the above material design optimization, the external quantum efficiency (EQE) of the organic-inorganic antimony halide LED has been effectively improved. However, the maximum EQE is still less than 7% at present, which is still significantly different from the requirements of commercial application. The main reason for the current efficiency limitation is that the existing researches are mostly focused on the modification of the organic-inorganic antimony halide film itself, and the optimization of the internal interface structure of the device still lacks systematic and in-depth exploration. Therefore, through interface engineering to improve the injection, transport and recombination behavior of charge carriers will become a key way to further improve the light-emitting efficiency of the antimony halide light-emitting diode. Strengthening the interface regulation is not only expected to significantly improve the external quantum efficiency, but also to improve the device stability and spectral purity, and to promote the practical application of this kind of material in the display, lighting and other optoelectronic fields. SUMMARY

[0004] The present application aims at the deficiencies of the prior art, and provides a method for preparing an organic-inorganic antimony halide light-emitting diode by optimizing the interface, forming a pi-pi stacking structure between the organic-inorganic hybrid antimony halide light-emitting layer and the organic electron transport layer, enhancing the carrier transport efficiency, and realizing the preparation of a high-efficiency light-emitting device.

[0005] To achieve the above object, the technical scheme adopted by the present application is as follows: An organic-inorganic hybrid antimony halide light-emitting diode, characterized in that it comprises, in sequence, a conductive transparent glass, a hole transport layer, an organic-inorganic hybrid antimony halide light-emitting layer, an organic electron transport layer, an electrode modification layer and a metal electrode layer; wherein the organic-inorganic hybrid antimony halide contains a specific carbazole functional group.

[0006] Further, the chemical formula of the organic-inorganic hybrid antimony halide light-emitting layer is: (C 27 H 22 NPR)2Sb2X8, wherein X represents Cl or Br; R includes but is not limited to methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, phenyl, naphthyl.

[0007]

[0008] Further, the specific synthesis route of the organic-inorganic hybrid antimony halide is as follows:

[0009] The specific steps are as follows: SbX3 and (C 27 H 22 NPR)2Sb2X8 are dissolved in an appropriate amount of dichloromethane in a molar ratio of 1:2 to form a clear precursor solution, then excess anhydrous ether is diffused into the precursor solution, and after a period of time, (C 27 H 22The NPR)2Sb2X8 crystals were washed with a small amount of anhydrous diethyl ether and then vacuum dried.

[0010] Furthermore, the organic electron transport layer should contain the following structure with characteristic functional groups:

[0011] Furthermore, a method for preparing an organic-inorganic hybrid antimony halide light-emitting diode includes the following steps: (1) Prepare an organic-inorganic hybrid antimony halide precursor solution with a concentration of 1-10 mg / mL: Take a certain amount of (C 27 H 22 NPR)2Sb2X8 was dissolved in an organic solvent, mixed thoroughly, and then filtered to obtain a clear precursor solution.

[0012] (2) Cleaning the conductive transparent electrodes: First, wash the conductive transparent electrodes with dish soap and water, then use acetone, deionized water and anhydrous ethanol to ultrasonically clean the substrate with transparent electrodes in sequence. After cleaning, blow dry with a nitrogen gun and place in an ultraviolet-ozone generator for treatment, finally obtaining a clean and wetted substrate.

[0013] (3) Preparation of hole transport layer: spin-coating hole transport layer on the prepared substrate and annealing treatment, with a thickness of 10~50 nanometers.

[0014] (4) Preparation of organic-inorganic hybrid antimony halide light-emitting layer: spin-coating the prepared antimony halide precursor solution onto the hole transport layer with a thickness of 10~100 nanometers.

[0015] (5) Preparation of electron transport layer: Electron transport layer is deposited on metal halide light-emitting layer with a thickness of 10~60 nanometers.

[0016] (6) Preparation of electron modification layer: Electrode modification layer is deposited on electron transport layer by vapor deposition.

[0017] (7) Electrode preparation: A metal electrode layer with a specific pattern is deposited on the electrode modification layer by vapor deposition, with a thickness of 100~500 nanometers.

[0018] Preferably, the precursor organic solvent is one of dichloromethane, trichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, and acetone.

[0019] Preferably, the conductive transparent electrode is ITO or FTO; the hole transport layer is one of PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid)), PVK (poly(9-vinylcarbazole)), or Poly-TPD poly[bis(4-phenyl)(4-butylphenyl)amine]; and the electrode modification layer is LiF or MoO. xThe metal electrode layer is Au, Ag, Al or Cu.

[0020] Preferably, the organic electron transport layer is TmPyPB (1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene), B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), TmPPPyTz (2,4,6-tris(3-(1H-pyrazol-1-yl)phenyl)-1,3,5-triazine), or TAZ (3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl). (-1,2,4-triazole), Liq (8-hydroxyquinoline-lithium), TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)), BCP ((2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)), Bphen (4,7-diphenyl-o-phenanthroline), PO-T2T (2,4,6-tris[3-(diphenylphosphoxy)phenyl]-1,3,5-triazole)

[0021] Using TPBi as the organic electron transport layer, and selecting organic-inorganic hybrid antimony halides without and containing carbazole as comparative examples and embodiments, respectively, this invention further illustrates the improvement in charge transport capability of organic-inorganic hybrid antimony halide light-emitting diodes by the introduction of the carbazole group. Any modifications and substitutions made to the methods, steps, or conditions of this invention without departing from its essence are within the scope of this invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the organic-inorganic hybrid antimony halide light-emitting diode described in this invention; Figure 2 a and b are schematic diagrams of the comparative example and the embodiment, respectively.

[0023] Figure 3 a and b show the Fourier transform infrared (FTIR) spectra of the comparative and exemplary cases after interaction with TPBi, respectively. Figure 3 c and d show the X-ray photoelectron spectra (XPS) of the comparative and exemplary examples after interaction with TPBi, respectively.

[0024] Figure 4 a and b show the surface potential diagrams measured by Kelvin probe microscopy (KPFM), corresponding to the comparative example and the embodiment after interaction with TPBi, respectively.

[0025] Figure 5 a and b are the current density-voltage-brightness curves, external quantum efficiency-current density curves, and device lifetime curves of the LED devices in the comparative example and the embodiment, respectively. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, TPBi is used as the organic electron transport layer. A carbazole-containing (TPPEtCz)2Sb2Br8 (where TPPEtCz represents (9-ethyl-9H-carbazole-3-yl)triphenylphosphine) luminescent layer is selected as an example, and a carbazole-free (TPPEt)2SbBr5 (where TPPEt represents ethyltriphenylphosphine) luminescent layer is selected as a comparative example. The invention will be further described in detail below with reference to specific operations and accompanying drawings. It should be emphasized that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0027] Example (1) Cleaning the substrate: First, thoroughly wash the ITO conductive glass with dish soap and water to remove surface dust and oil. Then, place it on a PTFE rack specifically for ITO conductive glass to isolate each piece of ITO conductive glass. Next, perform ultrasonic cleaning in the order of acetone, deionized water, and anhydrous ethanol, with each ultrasonic cleaning lasting 5-15 minutes. After cleaning, dry the ITO conductive glass with a nitrogen gun and place it in an ultraviolet ozone generator for 5-20 minutes.

[0028] (2) Preparation of hole transport layer: PEDOT:PSS aqueous solution was filtered through a 0.22-micron aqueous nylon tube and spin-coated onto the ITO conductive glass surface obtained in step (1) at 4000 rpm for 60 seconds in an air environment; then annealed at 150°C for 10-20 minutes to a thickness of 10-50 nanometers. After cooling to room temperature, it was transferred to a glove box filled with nitrogen.

[0029] (3) Preparation of organic-inorganic hybrid antimony halide single crystals: 0.2 mmol of TPPEtCzBr powder containing carbazole groups and 0.1 mmol of SbBr3 powder were dissolved in 1 mL of dichloromethane solution to form a clear precursor solution. Then, 2 mL of anhydrous diethyl ether was diffused into the precursor solution. After a period of time, (C 27 H 22 The NPR)2Sb2X8 crystals were washed with a small amount of anhydrous diethyl ether and then vacuum dried.

[0030] (4) Preparation of organic-inorganic hybrid antimony halide luminescent layer: In a nitrogen-filled glove box, 0.01 mmol of (TPPEtCz)2Sb2Br8 single crystal powder was dissolved in 3 mL of dichloromethane solution and stirred at 30 °C for 2-6 hours using a constant-temperature magnetic stirrer. After cooling to room temperature, the solution was filtered through a 0.45 μm organic nylon filter to obtain a clear precursor solution. The above solution was spin-coated onto a PEDOT:PSS film at 4000 rpm for 60 seconds to obtain an organic-inorganic antimony halide luminescent layer with a thickness of 10-100 nm.

[0031] (5) Preparation of electron transport layer: The substrate containing the antimony halide luminescent layer obtained in step (4) is placed upside down on the substrate holder, and a small amount of TPBi powder is placed in the crucible inside the organic evaporation source; then, under a vacuum degree of less than 1×10 -4 Under the conditions of pa, TPBi was deposited at a rate of 0.1~0.5 Å / s to a thickness of 10~60 nm.

[0032] (6) Preparation of electrode modification layer: The substrate containing the electron transport layer obtained in step (5) is placed upside down on the substrate holder, and a small amount of LiF is placed in the molybdenum boat above the metal evaporation source; then, under a vacuum degree of less than 1×10 -4 Under Pa conditions, LiF was deposited at a rate of 0.1–0.2 Å / s to a thickness of 0.5–2 nm.

[0033] (7) Preparation of metal electrode: Use a cotton swab with acetone to wipe away the multiple functional layers above the transparent electrode part, thereby exposing the negative electrode of the transparent electrode; then place it face down in the fixed pattern mask, and place an appropriate amount of Al in the molybdenum boat above the metal evaporation source; then, under a vacuum degree of less than 1×10 -4 Al was deposited at a rate of 1–5 Å / s under Pa conditions, with a thickness of 100–500 nm.

[0034] Comparative Example The other steps are completely consistent with the example, except that in step (3), the carbazole-containing TPPETCzBr powder is replaced with carbazole-free TPPETBr powder, and the resulting luminescent material has the structural formula (TPPEt)2SbBr5.

[0035] Figure 1 This is a schematic diagram of the structure of the organic-inorganic hybrid antimony halide light-emitting device according to the present invention. It includes a conductive transparent glass, a hole transport layer, an organic-inorganic hybrid antimony halide light-emitting layer, an electron transport layer, an electrode modification layer, and a metal electrode arranged sequentially.

[0036] Figure 2 The diagrams shown are structural schematics of the comparative example and the embodiment, respectively.Figure 3 FTIR spectral analyses of a and b show that when TPBi is deposited on an organic-inorganic hybrid antimony halide film containing carbazole, the stretching vibration peaks of its CN and C=N bonds exhibit a greater wavenumber shift compared to pure TPBi films; however, when deposited on films without carbazole, there is almost no shift, indicating an interaction between the carbazole moiety and the benzimidazole group of TPBi. Furthermore, XPS tests were performed to assess the interaction between the comparative examples and TPBi (e.g., ...). Figure 3 (c, d) The pure TPBi film not only exhibits the CN and C=N peaks of the benzimidazole group, but also displays the typical π-π satellite peaks (405.82 eV) of N-containing aromatic compounds. When deposited on the surface of the examples, the π-π satellite peaks of TPBi showed significant enhancement and broadening, confirming the existence of a parallel stacking structure dominated by π-π interactions, while no significant changes were observed in the comparative examples. Therefore, XPS analysis directly confirmed the existence of π–π interactions between the carbazole-containing organic-inorganic hybrid antimony halide film and TPBi, thus creating efficient charge transport channels at the molecular scale. In contrast, the carbazole-free organic-inorganic hybrid antimony halide film only has simple physical contact with TPBi, resulting in limited charge transport channels.

[0037] Figure 4 a and b represent the surface morphology and potential of the comparative and exemplary films after interaction with TPBi, respectively. The unmodified film exhibits a corrugated surface due to rapid crystallization, while the carbazole-modified film shows high density and uniformity due to the delayed crystallization time. Simultaneously, the potential difference of the film significantly increases due to the interaction with TPBi, indicating an overall upward shift of the emitter layer energy levels. This improves the alignment of the energy bands with the transport layer, thereby reducing the injection barrier and minimizing interfacial charge accumulation, thus promoting faster injection of holes and electrons.

[0038] Figure 5 The current density-voltage-luminance curves, external quantum efficiency-current density curves, and half-life curves of the light-emitting diode devices in the comparative example and the embodiment are shown respectively. Compared with the comparative example, the light-emitting device prepared by the carbazole group-modified organic-inorganic hybrid antimony halide film shows significant improvements in luminous brightness, external quantum efficiency, and operating lifetime.

[0039] Those skilled in the art will readily understand that the above description is merely one of the preferred embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An organic-inorganic hybrid antimony halide light-emitting diode, characterized in that, It consists of, in sequence, conductive transparent glass, a hole transport layer, an organic-inorganic hybrid antimony halide light-emitting layer, an organic electron transport layer, an electrode modification layer, and a metal electrode layer.

2. The organic-inorganic hybrid antimony halide light-emitting diode according to claim 1, characterized in that: The organic-inorganic hybrid antimony halide is an antimony halide containing a carbazole functional group, wherein the chemical formula of the carbazole functional group is C. 12 The structure of H9N is shown below:

3. The organic-inorganic hybrid antimony halide light-emitting diode according to claim 1, characterized in that: The light-emitting layer is an organic-inorganic hybrid antimony halide containing carbazole functional groups, with the chemical formula (C... 27 H 22 NPR)2Sb2X8, its structure is shown below: ； Where X represents Cl or Br; R replaces hydrogen atoms as protecting groups, and R includes, but is not limited to, methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, phenyl, and naphthyl.

4. The organic-inorganic hybrid antimony halide light-emitting diode according to claim 1, characterized in that, The organic-inorganic hybrid antimony halide was prepared by a one-step method, and the specific synthetic route is shown below:

5. The organic-inorganic hybrid antimony halide according to claim 4, characterized in that, The synthesis steps of the organic-inorganic hybrid antimony halide are as follows: SbX3 and (C 27 H 22 NPR)2Sb2X8 was dissolved in an appropriate amount of dichloromethane at a molar ratio of 1:2 to form a clear precursor solution. Then, excess anhydrous diethyl ether was diffused into the precursor solution. After a period of time, (C) was obtained. 27 H 22 The NPR)2Sb2X8 crystals were washed with a small amount of anhydrous diethyl ether and then vacuum dried.

6. The organic-inorganic hybrid antimony halide light-emitting diode according to claim 1, characterized in that, The preparation process of the precursor solution for the organic-inorganic hybrid antimony halide luminescent layer is as follows: take a certain amount of (C 27 H 22 NPR)₂Sb₂X₈ is dissolved in any one of dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, or acetone. After stirring until homogeneous, the solution is filtered to obtain a clear precursor solution. The concentration of the obtained organic-inorganic hybrid antimony halide precursor solution is 1–20 mg / mL.

7. The organic-inorganic hybrid antimony halide light-emitting diode according to claim 1, characterized in that, The organic electron transport layer contains functional groups capable of π-π interactions with the carbazole group in the organic-inorganic hybrid antimony halide, as follows: ; Common organic electron transport layers derived from this include, but are not limited to: TmPyPB (1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene), B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), TmPPPyTz (2,4,6-tris(3-(1H-pyrazol-1-yl)phenyl)-1,3,5-triazine), and TAZ (3-(4-biphenyl)-4-phenyl) -5-tert-butylphenyl-1,2,4-triazole), Liq (8-hydroxyquinoline-lithium), TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)), BCP ((2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)), Bphen (4,7-diphenyl-o-phenanthroline), PO-T2T (2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazole).

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