AC-driven perovskite light-emitting diode and preparation method and application thereof

Abstract

The invention particularly relates to an alternating-current driven perovskite light-emitting diode and a preparation method and application of the alternating-current driven perovskite light-emitting diode. The preparation method comprises the following steps: spin-coating a cleaned conductive glass substrate with an electron transport layer material, spin-coating an electron transport layer with a perovskite precursor solution, and carrying out annealing treatment to obtain a compact and uniform perovskite thin film; and spin-coating a hole transport layer material on the perovskite thin film, and then carrying out vacuum evaporation on an interface modification layer and a metal electrode on the hole transport layer to obtain the perovskite light-emitting diode device, and driving the device by using an alternating current driving mode. Compared with a traditional direct-current driving mode, the stability of the perovskite light-emitting diode device is remarkably improved through the alternating-current driving mode, the strategy has certain universality and effectiveness in the aspect of working stability of the perovskite light-emitting diode device, and commercial application of the perovskite light-emitting diode is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite light-emitting diodes, and in particular to an AC-driven perovskite light-emitting diode and a preparation method and application thereof. Background Art

[0002] Metal halide perovskite (MHP) materials can realize low-cost, high-performance light-emitting diodes. Since the first realization of room-temperature perovskite light-emitting diodes (PeLEDs) in 2014, through material and device structure engineering, the external quantum efficiency (EQE) of PeLEDs has exceeded 25%, which is currently comparable to the commercially successful OLED technology. However, problems such as poor stability and efficiency roll-off at high voltage / current density still hinder its ultimate commercial application. For example, practical applications require PeLEDs to have a longer lifetime (T 50 >1000h) and higher external quantum efficiency (EQE>10%). For MHP, its inherent ionic crystal properties lead to inevitable ion migration under the action of an external electric field, which is the main factor affecting its stability. Ion migration can adversely affect PeLEDs through lattice deformation, defect generation, ion doping, and chemical interactions.

[0003] To this end, various optimization strategies have been proposed to mitigate the effects of ion migration. For example, forming a multi-quantum well structure in quasi-two-dimensional perovskites can inhibit ion migration; mixing the A site with larger formamidinium cations can increase the energy barrier for ion migration; and defect passivation can prevent ion migration across grain boundaries. However, these material-based approaches have certain limitations in suppressing ion migration. Under the high voltage / current density operating conditions of direct current (DC) drive mode, charged ions are continuously affected by a single-directional electric field, which exacerbates ion migration and reduces device stability.

[0004] The alternating current (AC) driving method can effectively solve the problem of ion migration in perovskite and significantly improve the working stability of PeLED. By quickly changing the direction of the electric field, the AC driving mode can effectively avoid ion migration. In addition, the AC driving mode can also suppress the accumulation of carriers and heat generation at the interface, which helps to improve the efficiency and stability of the device. At the same time, PeLEDs driven by AC power can be directly connected to the household power supply, which can avoid the introduction of additional AC-DC converters and greatly save electricity. However, there is currently a lack of systematic research on AC-driven PeLEDs, and the device performance is still at a low level. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention proposes an AC-driven perovskite light-emitting diode and a preparation method and application thereof.

[0006] In order to solve the above technical problems, the present invention proposes a technical solution: a method for preparing an AC-driven perovskite light-emitting diode, comprising the following steps:

[0007] Step 1: fully dissolving the perovskite composition in dimethylformamide to prepare a perovskite precursor solution;

[0008] Step 2: Clean the conductive glass substrate, spin-coat the electron transport layer material on the surface of the conductive glass substrate to form an electron transport layer, and spin-coat the perovskite precursor solution prepared in step 1 on the electron transport layer. After annealing, a dense and uniform FAPbI3 or FAPbI2Br perovskite film is obtained;

[0009] Step 3: spin coating a hole transport layer material on the perovskite film to form a hole transport layer, and vacuum evaporating an interface modification layer and a metal electrode on the hole transport layer to obtain the perovskite light-emitting diode;

[0010] The perovskite light-emitting diode is driven using an AC driving mode.

[0011] Furthermore, in step 1, the perovskite composition includes at least one of 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, lead iodide or lead bromide.

[0012] Furthermore, in step 1, the perovskite composition is prepared by mixing 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, lead iodide, or a mixture of lead iodide and lead bromide in a molar ratio of 0.3:(2.0-2.2):1.

[0013] Furthermore, in step 1, the dissolution temperature of the perovskite composition is 50-60° C., and the dissolution time is 2-3 hours.

[0014] Furthermore, in step 2, the specific steps of cleaning the conductive glass substrate are: ultrasonically treating the ITO conductive glass substrate in detergent, acetone, isopropyl alcohol and ethanol in sequence for at least 15 minutes, drying with nitrogen, and then treating with ultraviolet ozone for 15 minutes.

[0015] Furthermore, in step 2, the electron transport layer material is zinc oxide, the spin coating speed of zinc oxide is 3500-4500 r / min, the spin coating time is 20-40 s, and the spin-coated zinc oxide is annealed at 140-160° C. for at least 10 min to obtain the electron transport layer.

[0016] Furthermore, in step 2, the electron transport layer material also includes a PEIE (polyethoxyethyleneimine) solution dissolved in 2-methoxyethanol, the spin coating speed of the PEIE solution is 4500-5500 r / min, the spin coating time is 20-40s, and the PEIE solution after spin coating is annealed at 90-110°C for at least 10 minutes.

[0017] Furthermore, in step 2, the perovskite film is a FAPbI3 perovskite film or a FAPbI2Br perovskite film; after the perovskite precursor solution is spin-coated, it is annealed at 90-100° C. for 10-15 minutes to obtain the FAPbI3 or FAPbI2Br perovskite film.

[0018] Furthermore, in step 3, when spin coating the hole transport layer material, TFB is dissolved in chlorobenzene to prepare a hole transport layer spin coating solution. The spin coating speed of the hole transport layer spin coating solution is 4000-5000 r / min, and the spin coating time is 40-50 s.

[0019] Furthermore, in step 3, the interface modification layer is MoO3, and the thickness of the interface modification layer is 6-10 nm.

[0020] Furthermore, in step 3, the metal electrode is an Ag electrode, and the thickness of the metal electrode is 80-120 nm.

[0021] Furthermore, the AC driving source in the AC driving mode is an AC voltage with a frequency less than 1 GHz, including but not limited to square wave, sine wave, triangle wave and other waveforms; preferably, the AC driving source is a 50 Hz square wave AC voltage.

[0022] The present invention prepares an AC-driven perovskite light-emitting diode device through the above-mentioned preparation method. The perovskite light-emitting diode device utilizes an AC driving mode strategy to achieve high stability of the perovskite light-emitting diode device.

[0023] In summary, compared with the prior art, the present invention achieves the following technical effects: by using a relatively low-frequency (<1GHz) square-wave AC voltage to drive the perovskite light-emitting diode device (such as FAPbI3), ion migration is significantly suppressed and the operating life is significantly improved; at the same time, this strategy is also applicable to mixed halide perovskite light-emitting diode devices (such as FAPbI2Br). The use of a relatively low-frequency square-wave AC voltage driving mode not only effectively improves the operating life of the mixed halide perovskite light-emitting diode device, but also effectively solves the problem of spectral drift caused by ion migration. This strategy has certain versatility and effectiveness in terms of the operating stability of perovskite light-emitting diode devices, which is conducive to the commercial application of perovskite light-emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of a perovskite light-emitting diode device according to Example 1 of the present invention;

[0026] Figure 2 This is a current density-voltage curve diagram of the perovskite light-emitting diode device in Example 1 of the present invention;

[0027] Figure 3 This is an irradiance-voltage curve diagram of the perovskite light-emitting diode device in Example 1 of the present invention;

[0028] Figure 4 This is an external quantum efficiency-voltage curve of the perovskite light-emitting diode device according to Example 1 of the present invention;

[0029] Figure 5 is the T of the perovskite light-emitting diode device in Example 1 of the present invention 50 Lifespan curve chart;

[0030] Figure 6 Schematic diagram of a perovskite light-emitting diode device according to Example 2 of the present invention;

[0031] Figure 7 is the T of the perovskite light-emitting diode device in Example 2 of the present invention 50 Lifespan curve chart;

[0032] Figure 8 Schematic diagram of a perovskite light-emitting diode device according to Comparative Example 1 of the present invention;

[0033] Figure 9 is the T of the perovskite light-emitting diode device in Comparative Example 1 of the present invention 50 Lifespan curve chart;

[0034] Figure 10 Schematic diagram of a perovskite light-emitting diode device according to Comparative Example 2 of the present invention;

[0035] Figure 11 This is a graph showing the external quantum efficiency-driving voltage frequency curve of the perovskite light-emitting diode device of Comparative Example 2 of the present invention.

[0036] In the above-mentioned Figure 1 、 6In Figures 8 and 10, it should be noted that ITO refers to ITO conductive glass substrate, ETL refers to electron transport layer, Perovskite refers to perovskite film, HTL refers to hole transport layer, and Elctrode refers to interface modification layer and metal electrode. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts should fall within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a method for preparing an AC-driven perovskite light-emitting diode, comprising the following steps:

[0040] Step 1: 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, and lead iodide were mixed in a molar ratio of 0.3:2.2:1, dissolved in dimethylformamide, and heated and stirred at 60°C on a hot plate in an N2 glove box for 2 hours to prepare a perovskite precursor solution;

[0041] Step 2: Clean the ITO conductive glass substrate, ultrasonicate it in glass cleaning solution, acetone, isopropanol, and ethanol for 15 minutes each, blow dry it with nitrogen to obtain a clean ITO conductive glass substrate, and treat it in ultraviolet ozone for 15 minutes; spin-coat zinc oxide on the surface of the cleaned conductive glass substrate at a speed of 4000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 150°C for 10 minutes to form a zinc oxide film; then spin-coat a PEIE solution (0.4wt%) dissolved in 2-methoxyethanol on the surface of the zinc oxide film at a speed of 5000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to form a PEIE film; then spin-coat the perovskite precursor solution prepared in step 1 on the PEIE film, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to obtain a dense and uniform FAPbI3 perovskite film;

[0042] Step 3: Dissolve 12 mg of TFB in 1 mL of chlorobenzene to obtain a hole transport layer spin coating solution, and spin-coat the hole transport layer spin coating solution on the perovskite layer at a spin coating speed of 4500 r / min for 45 seconds to form a hole transport layer; then, vacuum evaporate an interface modification layer MoO3 with a thickness of 8 nm and a metal electrode Ag with a thickness of 100 nm on the hole transport layer to obtain the perovskite light-emitting diode device.

[0043] The structure of the perovskite light-emitting diode device prepared in this embodiment is as follows: Figure 1 As shown, a 50Hz square wave AC voltage is used to drive the device. The driving mode is as follows: Figure 1 As shown in FIG, the relationship between the current density and voltage of the perovskite light-emitting diode device prepared in the embodiment is as follows: Figure 2 As shown, the device has a starting voltage of 1.1V and a brightness level of Figure 3 As shown; the external quantum efficiency of the device is 14.92%, as shown Figure 4 As shown; in AC drive mode, 2.2V voltage conditions, the device continuously works T 50 The life span is 424 minutes. Figure 5 shown.

[0044] Example 2

[0045] This embodiment 2 provides a method for preparing a perovskite light-emitting diode, comprising the following steps:

[0046] Step 1: 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, lead iodide, and lead bromide were mixed in a molar ratio of 0.3:2.2:0.67:0.33, dissolved in dimethylformamide, and heated and stirred at 60°C on a hot plate in an N2 glove box for 2 hours to prepare a perovskite precursor solution;

[0047] Step 2: Clean the ITO conductive glass substrate, ultrasonicate it in glass cleaning solution, acetone, isopropanol, and ethanol for 15 minutes each, blow dry it with nitrogen to obtain a clean ITO conductive glass substrate, and treat it in ultraviolet ozone for 15 minutes; spin-coat zinc oxide on the surface of the cleaned conductive glass substrate at a speed of 4000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 150°C for 10 minutes to form a zinc oxide film; then spin-coat a PEIE solution (0.4wt%) dissolved in 2-methoxyethanol on the surface of the zinc oxide film at a speed of 5000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to form a PEIE film; then spin-coat the perovskite precursor solution prepared in step 1 on the PEIE film, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to obtain a dense and uniform FAPbI2Br perovskite film;

[0048] Step 3: Dissolve 12 mg of TFB in 1 mL of chlorobenzene to obtain a hole transport layer spin coating solution, and spin-coat the hole transport layer spin coating solution on the perovskite layer at a spin coating speed of 4500 r / min for 45 seconds to form a hole transport layer; then, vacuum-evaporate an interface modification layer MoO3 with a thickness of 8 nm and a metal electrode Ag with a thickness of 100 nm on the hole transport layer to obtain the FAPbI2Br perovskite light-emitting diode device.

[0049] The structure of the FAPbI2Br perovskite light-emitting diode device prepared in this embodiment is as follows: Figure 6 As shown, the device is driven by 50Hz square wave AC voltage and DC voltage respectively. The driving mode is as follows Figure 6 As shown. When driven by square wave AC voltage and DC 2.2V voltage, the device T 50 The lifespans are 243.7 min and 7.1 min respectively. Figure 7 As shown in the figure, the AC driving mode also has a significant effect on improving the lifespan of the hybrid halide perovskite device, proving that the strategy of adopting the AC driving mode has the potential to significantly improve the stability of various perovskite light-emitting diodes.

[0050] Comparative Example 1

[0051] This comparative example provides a method for preparing a perovskite light-emitting diode, comprising the following steps:

[0052] Step 1: 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, and lead iodide were mixed in a molar ratio of 0.3:2.2:1, dissolved in dimethylformamide, and heated and stirred at 60°C on a hot plate in an N2 glove box for 2 hours to prepare a perovskite precursor solution;

[0053] Step 2: Clean the ITO conductive glass substrate, ultrasonicate it in glass cleaning solution, acetone, isopropanol, and ethanol for 15 minutes each, blow dry it with nitrogen to obtain a clean ITO conductive glass substrate, and treat it in ultraviolet ozone for 15 minutes; spin-coat zinc oxide on the surface of the cleaned conductive glass substrate at a speed of 4000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 150°C for 10 minutes to form a zinc oxide film; then spin-coat a PEIE solution (0.4wt%) dissolved in 2-methoxyethanol on the surface of the zinc oxide film at a speed of 5000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to form a PEIE film; then spin-coat the perovskite precursor solution prepared in step 1 on the PEIE film, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to obtain a dense and uniform FAPbI3 perovskite film;

[0054] Step 3: Dissolve 12 mg of TFB in 1 mL of chlorobenzene to obtain a hole transport layer spin coating solution, and spin-coat the hole transport layer spin coating solution on the perovskite layer at a spin coating speed of 4500 r / min for 45 seconds to form a hole transport layer; then, vacuum evaporate an interface modification layer MoO3 with a thickness of 8 nm and a metal electrode Ag with a thickness of 100 nm on the hole transport layer to obtain the perovskite light-emitting diode device.

[0055] In this comparative example, a DC voltage is used to drive the perovskite light-emitting diode device prepared in this comparative example. The driving mode is as follows: Figure 8 As shown, the perovskite light-emitting diode device prepared in this comparative example is in DC driving mode and 2.2V voltage condition. The device works continuously T 50 The life span is 10.3min, such as Figure 9 Compared with Example 1, it can be seen that AC driving can significantly improve the working stability of the perovskite light-emitting diode device.

[0056] Comparative Example 2

[0057] This comparative example provides a method for preparing a perovskite light-emitting diode, comprising the following steps:

[0058] Step 1: 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, and lead iodide were mixed in a molar ratio of 0.3:2.2:1, dissolved in dimethylformamide, and heated and stirred at 60°C on a hot plate in an N2 glove box for 2 hours to prepare a perovskite precursor solution;

[0059] Step 2: Clean the ITO conductive glass substrate, ultrasonicate it in glass cleaning solution, acetone, isopropanol, and ethanol for 15 minutes each, blow dry it with nitrogen to obtain a clean ITO conductive glass substrate, and treat it in ultraviolet ozone for 15 minutes; spin-coat zinc oxide on the surface of the cleaned conductive glass substrate at a speed of 4000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 150°C for 10 minutes to form a zinc oxide film; then spin-coat a PEIE solution (0.4wt%) dissolved in 2-methoxyethanol on the surface of the zinc oxide film at a speed of 5000 r / min for 30 seconds, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to form a PEIE film; then spin-coat the perovskite precursor solution prepared in step 1 on the PEIE film, and thermally anneal it on a hot stage in an N2 glove box at 100°C for 10 minutes to obtain a dense and uniform FAPbI3 perovskite film;

[0060] Step 3: Dissolve 12 mg of TFB in 1 mL of chlorobenzene to obtain a hole transport layer spin coating solution, and spin-coat the hole transport layer spin coating solution on the perovskite layer at a spin coating speed of 4500 r / min for 45 seconds to form a hole transport layer; then, vacuum evaporate an interface modification layer MoO3 with a thickness of 8 nm and a metal electrode Ag with a thickness of 100 nm on the hole transport layer to obtain the perovskite light-emitting diode device.

[0061] In this comparative example, a square wave AC voltage of 10 Hz to 50 kHz is used to drive the perovskite light-emitting diode device prepared in this comparative example. The driving mode is as follows: Figure 10 As shown in FIG. 1 , the relationship between the efficiency of the perovskite light-emitting diode device prepared in this comparative example and the driving voltage frequency is shown in FIG. Figure 11 As shown in FIG. 1 , the efficiency of the device remains almost unchanged in the frequency range of 10 Hz to 1 GHz, but when driven at high frequencies (greater than 1 GHz), the efficiency of the device decreases to a certain extent.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an AC-driven perovskite light-emitting diode, characterized in that: The following steps are involved: Step 1: Fully dissolving the perovskite composition in dimethylformamide to prepare a perovskite precursor solution; Step 2: Cleaning the conductive glass substrate, spin-coating an electron transport layer material on the surface of the conductive glass substrate to form an electron transport layer, and spin-coating the perovskite precursor solution prepared in step 1 on the electron transport layer, and obtaining a dense and uniform perovskite film after annealing; Step 3: spin coating a hole transport layer material on the perovskite film to form a hole transport layer, and vacuum evaporating an interface modification layer and a metal electrode on the hole transport layer to obtain the perovskite light-emitting diode; The perovskite light-emitting diode is driven using an AC driving mode.

2. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: In step 1, the perovskite composition includes at least one of 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, lead iodide, or lead bromide.

3. The method for preparing an AC-driven perovskite light-emitting diode according to claim 2, wherein: In step 1, the perovskite composition is prepared by mixing 2,2'-[oxybis(ethyleneoxy)]diethylamine, formamidine iodide, lead iodide, or a mixture of lead iodide and lead bromide in a molar ratio of 0.3:(2.0-2.2):

1.

4. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: In step 2, the electron transport layer material is zinc oxide, the spin coating speed of zinc oxide is 3500-4500 r / min, the spin coating time is 20-40 s, and the spin-coated zinc oxide is annealed at 140-160° C. for at least 10 min to obtain the electron transport layer.

5. The method for preparing an AC-driven perovskite light-emitting diode according to claim 5, wherein: In step 2, the electron transport layer material further includes a PEIE solution dissolved in 2-methoxyethanol, the PEIE solution is spin-coated at a speed of 4500-5500 r / min, the spin-coating time is 20-40 s, and the spin-coated PEIE solution is annealed at 90-110° C. for at least 10 min.

6. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: When spin coating the hole transport layer material in step 3, TFB is dissolved in chlorobenzene to prepare a hole transport layer spin coating solution. The spin coating speed of the hole transport layer spin coating solution is 4000-5000 r / min, and the spin coating time is 40-50 s.

7. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: In step 3, the interface modification layer is MoO3, and the thickness of the interface modification layer is 6-10 nm.

8. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: In step 3, the metal electrode is an Ag electrode, and the thickness of the metal electrode is 80-120 nm.

9. The method for preparing an AC-driven perovskite light-emitting diode according to claim 1, wherein: The AC driving source in the AC driving mode is an AC voltage with a frequency less than 1 GHz.

10. An AC-driven perovskite light-emitting diode, characterized in that: The perovskite light-emitting diode is manufactured using the preparation method of the AC-driven perovskite light-emitting diode according to any one of claims 1 to 9, and the perovskite light-emitting diode is driven in an AC driving mode.

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