Perovskite layer passivation method and product and application thereof

Abstract

The invention discloses a passivation method of a perovskite layer and a product and application thereof, belongs to the technical field of luminescent devices, and utilizes curcumin to carry out bulk phase passivation on the perovskite layer. The invention also discloses the curcumin passivated perovskite layer prepared by the preparation method and an application of the curcumin passivated perovskite layer in a perovskite light emitting diode. According to the passivation method, curcumin is introduced as an additive, the deep energy level defect of the perovskite layer can be passivated, a good passivation effect is achieved, the problem that a traditional perovskite layer is poor in light emitting performance is solved, and the obtained curcumin-passivated perovskite layer is stable in property and high in light emitting efficiency. Therefore, the external quantum efficiency and the stability of the perovskite near-infrared light-emitting diode can be effectively improved when the perovskite near-infrared light-emitting diode is applied to the perovskite near-infrared light-emitting diode.

Description

Technical Field

[0001] The present invention belongs to the technical field of light-emitting devices, and in particular relates to a passivation method for a perovskite layer and a product and application thereof. Background Art

[0002] Metal halide perovskites have emerged as a promising optoelectronic material due to their advantages such as narrow bandwidth, high photoluminescence quantum yield and simple preparation process, making them very suitable for application in solar cells and light-emitting diodes. Despite significant progress in visible light applications, the fundamental bandgap limitation of metal halide perovskites poses a challenge to further development, especially for practical applications in the infrared spectral region. The development of near-infrared light-emitting diodes is of great significance for various applications, including sensing, computing, bioimaging, optical communications and night vision technology. Therefore, how to extend the operating wavelength of perovskite light-emitting diodes from the visible light region to the near-infrared region is a key scientific issue that needs to be solved urgently.

[0003] Given their high absorption coefficients and excellent charge transfer capabilities, metal halide perovskites are ideal sensitizing host materials for ytterbium ions. Incorporating ytterbium ions into the perovskite matrix can produce near-infrared quantum cutoff emission with a wavelength close to 1000nm, and theoretically achieve quantum efficiencies up to 200%. However, the inherent defects and instabilities of perovskite materials pose challenges, limiting the performance of ytterbium-doped perovskite light-emitting diodes.

[0004] In the prior art, the patent technology with publication number CN 116004229 A discloses a chlorophyll-modified CsPbCl3:Yb 3+ Perovskite film and its preparation method and application, which uses a precursor solution containing chlorophyll to prepare the perovskite film, but the resulting product has good technical effects only in the application of silicon solar cells. If it is directly applied to perovskite light-emitting diodes, it may cause additional charge traps, limit current flow, and thus affect the performance of perovskite light-emitting diodes. In addition, chlorophyll may cause light loss during the passivation process because it itself, as a light-absorbing molecule, may consume the luminous energy of the perovskite light-emitting diode, resulting in reduced efficiency.

[0005] Therefore, how to provide a suitable passivating agent to improve the luminous efficiency and stability is a technical problem that those skilled in the art need to solve urgently. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a curcumin-passivated perovskite layer and a preparation method and application thereof.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for passivating a perovskite layer uses curcumin to perform bulk phase passivation on the perovskite layer.

[0009] Preferably, the method specifically comprises the following steps:

[0010] (1) adding curcumin to a lead chloride solution to obtain a precursor solution A; dissolving cesium chloride and ytterbium chloride hexahydrate in an organic solvent, heating and stirring, to obtain a precursor solution B;

[0011] (2) coating the precursor solution A on the surface of a glass substrate and performing a primary annealing treatment, and then coating the precursor solution B and performing a secondary annealing treatment, thereby obtaining a curcumin-passivated perovskite layer.

[0012] Preferably, in the precursor solution A, the concentration of curcumin is 1-3 mg / mL, and the concentration of lead chloride is 1.5 mmol / mL.

[0013] Preferably, in the precursor solution B, the concentration of cesium chloride is 1.5 mmol / mL, and the concentration of ytterbium chloride hexahydrate is 0.5 mmol / mL.

[0014] Preferably, the primary annealing is performed at a temperature of 100° C. and for a time of 5 minutes.

[0015] Preferably, the secondary annealing is performed at a temperature of 250° C. and for 10 minutes.

[0016] The curcumin-passivated perovskite layer was prepared according to the above-mentioned preparation method.

[0017] Application of the curcumin-passivated perovskite layer in perovskite light-emitting diodes as described above.

[0018] A perovskite near-infrared light-emitting diode, comprising an electron transport layer and a hole transport layer, and also comprising the above-mentioned curcumin-passivated perovskite layer;

[0019] The curcumin-passivated perovskite layer is located between the electron transport layer and the hole transport layer.

[0020] A method for preparing a perovskite near-infrared light-emitting diode comprises the following steps:

[0021] (1) Cleaning, drying and ultraviolet ozone treatment of the ITO substrate in sequence;

[0022] (2) preparing an electron transport layer on the surface of an ITO substrate;

[0023] (3) using the above-mentioned passivation method of a perovskite layer of the present invention to prepare a perovskite layer on the surface of the electron transport layer, and passivating the perovskite layer;

[0024] (4) forming a hole transport layer on the surface of the passivated perovskite layer;

[0025] (5) A metal electrode is prepared on the surface of the hole transport layer to obtain a perovskite near-infrared light-emitting diode.

[0026] In summary, the present invention proposes a method for effectively passivating a perovskite layer, which can improve the performance and stability of perovskite near-infrared light-emitting diodes. Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention solves the problem of weak luminescence performance of the traditional perovskite layer by introducing curcumin in the process of passivating the perovskite layer, wherein the introduced curcumin can effectively enhance the compactness of the perovskite layer and reduce the roughness of the perovskite layer, and because curcumin is easily combined with lead ions, it can reduce the uncoordinated excess lead ions in the perovskite, passivate the defects in the perovskite layer, and improve the infrared luminescence intensity of the perovskite layer. In addition, the curcumin-passivated perovskite layer prepared by the present invention has stable properties, and can be applied to perovskite light-emitting diodes to effectively improve the external quantum efficiency and stability of the perovskite light-emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 The photoluminescence spectra of the curcumin-passivated perovskite layers prepared in Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention are shown;

[0030] Figure 2 The SEM images of the curcumin-passivated perovskite layers prepared in Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention;

[0031] Figure 3 AFM images of flavin-passivated perovskite layers prepared in Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention;

[0032] Figure 4 The JVL curve diagram of the perovskite layer prepared in Comparative Example 1 and Example 2 of the present invention after being applied to a perovskite light-emitting diode (Example 4);

[0033] Figure 5 EQE diagram after the perovskite layer prepared in Comparative Example 1 and Example 2 of the present invention is applied to a perovskite light-emitting diode (Example 4);

[0034] Figure 6This is a long-term operation stability diagram of the perovskite layer prepared in Comparative Example 1 and Example 2 of the present invention after being applied to a perovskite light-emitting diode (Example 4);

[0035] Figure 7 This is an electroluminescence spectrum diagram of the near-infrared band after the perovskite layer prepared in Comparative Example 1 and Example 2 of the present invention is applied to a perovskite light-emitting diode (Example 4). DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources;

[0039] Among them, cesium chloride, lead chloride, and ytterbium chloride hexahydrate were purchased from Macklin, and curcumin was purchased from Aladdin; glass substrates and ITO substrates were purchased from Yingkou Youxuan Trading Co., Ltd., with specifications of 19.5mm*19.5mm;

[0040] Unless otherwise specified, the room temperature or normal temperature in the embodiments of the present invention is 25±3°C.

[0041] Example 1

[0042] A method for passivating a perovskite layer comprises the following steps:

[0043] (1) Preparation of precursor solution A: 340 mg of PbCl2 powder and 2 mL of dimethyl sulfoxide were added to a 5 mL glass bottle, and 2 mg of curcumin powder was added to make the curcumin concentration 1 mg / mL. The glass bottle was placed on a magnetic heating stirrer and heated to 40°C and magnetically stirred for 5 h until the powder was completely dissolved. The precursor solution A was obtained by filtering.

[0044] (2) Preparation of precursor solution B: 51 mg of CsCl powder, 54 mg of YbCl3·6H2O powder and 2 mL of methanol were added to a 5 mL glass bottle. The glass bottle was placed on a magnetic heating stirrer and heated to 40°C and magnetically stirred for 5 h until the powder was completely dissolved. The precursor solution B was obtained by filtering.

[0045] (3) Substrate pretreatment: First, the glass sheet was placed in deionized water, ethanol, acetone, and isopropanol for ultrasonic treatment for 15 min, 15 min, 10 min, and 10 min, respectively. The glass sheet was then placed in a 75°C hot air oven and dried for 5 min. Finally, it was treated with UV ozone for 40 min to remove the groups on the surface of the glass sheet to obtain a clean glass sheet that can be used to prepare samples.

[0046] (4) Preparation of perovskite layer: Precursor solution A prepared in step (1) and precursor solution B prepared in step (2) were heated to 70°C respectively, 80 μL of the heated precursor solution A was dropped on a glass sheet, and then the mixture was slurried at 4000 rpm for 30 s, and then annealed at 100°C for 5 min to obtain a glass sheet after primary annealing; then 80 μL of the heated precursor solution B was dropped on the glass sheet after primary annealing, and then the mixture was slurried at 4000 rpm for 30 s, and then annealed at 250°C for 10 min to obtain a curcumin-passivated perovskite layer.

[0047] Example 2

[0048] A passivation method for a perovskite layer, which is different from Example 1 only in that the amount of curcumin added in step (1) is 4 mg, so that the curcumin concentration is 2 mg / mL. The remaining process steps and parameters are the same as those in Example 1.

[0049] Example 3

[0050] A passivation method for a perovskite layer, which is different from Example 1 only in that the amount of curcumin added in step (1) is 6 mg, so that the curcumin concentration is 3 mg / mL. The remaining process steps and parameters are the same as those in Example 1.

[0051] Example 4

[0052] A method for preparing a perovskite near-infrared light-emitting diode comprises the following steps:

[0053] (1) The ITO substrate was ultrasonically treated in detergent, ethanol, and isopropanol for 15 min, 15 min, and 10 min, respectively, and then placed in a 75°C hot air oven for drying for 5 min. Finally, it was treated with ultraviolet ozone for 40 min to remove the groups on the surface of the glass sheet, thereby obtaining a clean ITO substrate that can be used to prepare devices.

[0054] (2) 100 μL of 15 wt% tin dioxide aqueous dispersion was mixed with 1 mL of ultrapure water, and the mixture was coated on the surface of an ITO substrate after being fully stirred. The mixture was annealed at 150° C. for 30 minutes to prepare an electron transport layer on the surface of the ITO substrate.

[0055] (3) According to the technical solution in Example 1, a curcumin-passivated perovskite layer was prepared on the surface of the electron transport layer.

[0056] (4) The sample prepared in step (3) is placed in an evaporator, and 4,4′-bis(carbazole-9-yl)biphenyl (CBP) and 4,4′,4″-tri(carbazole-9-yl)triphenylamine (TCTA) are evaporated in a high vacuum to obtain a hole transport layer. The thickness of CBP is 45 nm, and the thickness of TCTA is 35 nm.

[0057] (5) A gold electrode is evaporated on the surface of the hole transport layer. The thickness of the metal electrode is 100 nm.

[0058] Comparative Example 1

[0059] A method for passivating a perovskite layer, which is different from Example 1 only in that curcumin is not added in step (1), so that the curcumin concentration is 0 mg / mL. The remaining process steps and parameters are the same as those in Example 1.

[0060] Technical effects:

[0061] Unless otherwise specified, CCM in the drawings of the present invention refers to curcumin, and different concentrations correspond to the concentrations of curcumin in Example 1, Example 1, Example 2 and Example 3, respectively.

[0062] Figure 1 The photoluminescence spectra of perovskite layers containing different concentrations of curcumin show that the luminescence intensity of the film after passivation with curcumin is higher, especially the luminescence intensity of near-infrared light is greatly improved.

[0063] Figure 2 These are SEM images of perovskite layers containing different concentrations of curcumin. It can be seen that the grain size of the perovskite layer after curcumin passivation is reduced, the grains are more continuous, and the number of surface holes is reduced.

[0064] Figure 3 The AFM images of the perovskite layer containing different concentrations of curcumin show that the surface morphology of the perovskite layer after passivation with curcumin is denser and the root mean square roughness is lower.

[0065] Figure 4 The JVL curves of the perovskite layers obtained in Comparative Example 1 and Example 2 after being applied to the perovskite light-emitting diode show that the irradiation intensity of the perovskite light-emitting diode prepared by the perovskite layer passivated with curcumin is higher, which can reach twice that of the unpassivated device.

[0066] Figure 5 This is an EQE curve diagram after the perovskite layer obtained in Comparative Example 1 and Example 2 is applied to the perovskite light-emitting diode. It can be seen that the EQE of the perovskite light-emitting diode prepared by the perovskite layer after curcumin passivation is higher, which can reach 3 times that of the unpassivated device.

[0067] Figure 6 This is a long-term operating stability diagram of the perovskite layer obtained in Comparative Example 1 and Example 2 after being applied to a perovskite light-emitting diode. It can be seen that the perovskite light-emitting diode prepared with the perovskite layer passivated with curcumin has stronger long-term operating stability, and the long-term operating life can reach 1.7 times that of the unpassivated device.

[0068] Figure 7 The electroluminescence spectra of the perovskite layers obtained in Comparative Example 1 and Example 2 after being applied to the perovskite light-emitting diodes show that the electroluminescence intensity of the perovskite light-emitting diodes prepared by the perovskite layer passivated with curcumin is higher, which can reach twice that of the unpassivated device.

[0069] Combination Figure 1 to Figure 7 It can be seen from the data that the present invention solves the problems of poor surface morphology, weak luminescence performance, and poor light-emitting diode performance existing in the traditional perovskite layer by passivating the perovskite layer with curcumin.

[0070] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for passivating a perovskite layer, characterized in that: Bulk passivation of perovskite layers using curcumin.

2. A passivation method for a perovskite layer according to claim 1, characterized in that: The specific steps include: (1) adding curcumin to a lead chloride solution to obtain a precursor solution A; dissolving cesium chloride and ytterbium chloride hexahydrate in an organic solvent, heating and stirring, to obtain a precursor solution B; (2) coating the precursor solution A on the surface of a glass substrate and performing a primary annealing treatment, and then coating the precursor solution B and performing a secondary annealing treatment, thereby obtaining a curcumin-passivated perovskite layer.

3. A passivation method for a perovskite layer according to claim 2, characterized in that: In the precursor solution A, the concentration of curcumin is 1-3 mg / mL, and the concentration of lead chloride is 1.5 mmol / mL.

4. The passivation method of a perovskite layer according to claim 2, characterized in that: In the precursor solution B, the concentration of cesium chloride is 1.5 mmol / mL, and the concentration of ytterbium chloride hexahydrate is 0.5 mmol / mL.

5. The passivation method of a perovskite layer according to claim 2, characterized in that: The primary annealing was performed at a temperature of 100° C. and for 5 minutes.

6. A passivation method for a perovskite layer according to claim 2, characterized in that: The secondary annealing temperature is 250°C and the time is 10 min.

7. The perovskite layer passivated with curcumin prepared by the preparation method according to any one of claims 1 to 6.

8. Application of the curcumin-passivated perovskite layer as claimed in claim 7 in a perovskite light-emitting diode.

9. A perovskite near-infrared light-emitting diode, comprising an electron transport layer and a hole transport layer, characterized in that: Also comprising the curcumin-passivated perovskite layer of claim 7; The curcumin-passivated perovskite layer is located between the electron transport layer and the hole transport layer.

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