Multicolor stacked perovskite / GaN laminated device and preparation method thereof

Abstract

The invention discloses a multicolor stacked perovskite / GaN laminated device, which comprises the following structures arranged from bottom to top: an n-type GaN layer, a multi-quantum well layer, a p-type GaN layer, an ITO layer, a hole transport layer, a perovskite layer and an electron transport layer, a cathode is arranged on the n-type GaN layer, and a cathode is arranged on the electron transport layer. The invention provides the preparation method of the multicolor stacked perovskite / GaN laminated device, the Pe-GaN series LED can be driven by two independent power supplies, and correspondingly, the brightness and the color of the device can be independently controlled. The light emitting of the two layers of devices is independently designed and controlled, so that the operation is simple and controllable, a huge transfer technology is avoided, and low-cost novel full-color display can be realized.

Description

Technical Field

[0001] The invention relates to a multi-color stacked perovskite / GaN stacked device and a preparation method thereof, belonging to the field of semiconductor materials and optoelectronic technology. Background Art

[0002] At present, the technical path to achieve white light LED shows two trends: one is the horizontal integration using the red, green and blue three-primary color array arrangement, and the other is the vertical integration with the series connection of the light-emitting layer as the core. Phosphor conversion is a common method for converting a single color light source (such as blue light or ultraviolet light) into white light. However, there will be some energy loss in the process of phosphor conversion, which reduces the light conversion efficiency; and because phosphor conversion is excited by absorbing light of a specific wavelength and re-radiating light of other wavelengths, color deviation or color unevenness may sometimes occur.

[0003] Therefore, researchers have proposed another method to produce white light without conversion loss, which involves combining three or more discrete LED chips of the primary colors of red (R), green (G), and blue (B) and arranging them side by side on the same plane. However, this method without conversion loss also exposes some shortcomings in practical applications. On the one hand, uneven color distribution and color edge effects are very likely to occur during the beam mixing process, which has a negative impact on the beam quality; on the other hand, since the red, green, and blue sub-pixels are assembled in a side-by-side structure, they will inevitably occupy a larger pixel area, limiting the resolution and pixel density of the display. In cutting-edge application scenarios that have extremely high requirements for display resolution, such as immersive virtual reality (VR) and augmented reality (AR) devices, medical imaging systems for precise diagnosis, and scientific visualization, this technical limitation may be difficult to meet its stringent requirements and needs to be further optimized and overcome. Summary of the invention

[0004] The present invention discloses a multi-color stacked perovskite / GaN stacked device to solve the above problems existing in the prior art.

[0005] The technical solution adopted by the present invention is:

[0006] A multi-color stacked perovskite / GaN stacked device includes the following structures arranged from bottom to top: n-type GaN layer, multi-quantum well layer, p-type GaN layer, ITO layer, hole transport layer, perovskite layer, electron transport layer, a cathode is arranged on the n-type GaN layer, and a cathode is arranged on the electron transport layer. The ITO layer is used as a common anode for two light-emitting structures.

[0007] Preferably, it also includes a light-emitting control circuit, which includes two independently controlled power supplies, wherein one end of one independent power supply is connected to the cathode on the n-type GaN layer, and the other end is connected to the ITO layer to drive the multi-quantum well light-emitting structure; one end of the other independent power supply is connected to the cathode on the electron transport layer, and the other end is connected to the ITO layer to drive the perovskite light-emitting structure.

[0008] Preferably, the n-type GaN layer is GaN doped with silicon or aluminum, with a thickness of 1-1.5 μm, and the p-type GaN layer is GaN doped with Mg, with a thickness of 70-100 nm.

[0009] Preferably, the multi-quantum well layer is an InGaN / GaN multi-quantum well structure.

[0010] Preferably, the hole transport layer is one or more of PEDOT:PSS, PVK, NiOx, PTAA or small molecule doped PEDOT:PSS, PEDOT:PSS / PTAA composite transport layer, and has a thickness of 30-50 nm.

[0011] Preferably, the electron transport layer is one or more of TPBi, TmPyPB or PO-T2T, and has a thickness of 40-60 nm.

[0012] Preferably, the chemical formula of the perovskite is L 2 (SMX 3 ) n-1 MX 4 ; Where M is a divalent metal cation, L is a long-chain organic cation, S is a monovalent cation, X is any one or more of the halogen anions I, Br, and Cl, and n (n = 1, 2, ..., ∞) is the semiconductor MX in the organic insulating layer 4 When n=∞, it has SMX 3 Structured 3D perovskite.

[0013] Preferably, the chemical formula of the perovskite is CsPbBr 3 or CsPb(Br x I 1-x ) 3 .

[0014] Preferably, the cathode is Al, Ag, Au, or a LiF / Al layer modified by a LiF thin layer.

[0015] The present invention also discloses a method for preparing the above-mentioned multi-color stacked perovskite / GaN stacked device, the steps of which include:

[0016] Step 1: Use PECVD technology to grow silicon dioxide on the ITO surface of the blue LED epitaxial wafer, then spin-coat photoresist on it and develop the pattern onto the photoresist;

[0017] Step 2, using RIE technology, using photoresist as a mask, to carve out sample steps;

[0018] Step 3, soaking the sample in ITO etching solution to remove the ITO layer under the step; soaking the sample in acetone solution to strip off the photoresist;

[0019] Step 4, anisotropically etching the sample using ICP technology until the n-GaN layer is etched;

[0020] Step 5, removing residual glue and silicon dioxide to obtain a sample with ITO / n-GaN steps;

[0021] Step 6: clean and ultrasonicate the sample, blow dry it with nitrogen, prepare a hole transport layer, a perovskite layer, an electron transport layer and a cathode in sequence above the ITO layer of the sample, prepare a cathode on the exposed n-GaN layer, and finally obtain a multi-color stacked perovskite / GaN stacked device.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention provides a method for preparing a multi-color stacked perovskite / GaN stacked device. The Pe-GaN series LED can be driven by two independent power supplies, and accordingly, the brightness and color of the device can be independently controlled. By independently designing and controlling the light emission of the two-layer device, the operation is simple and controllable, avoiding mass transfer technology, and is conducive to realizing a low-cost new full-color display.

[0024] 2. The present invention breaks through the limitations of traditional inorganic III-V semiconductor materials and focuses on perovskite materials with lower formation energy. Perovskite has the characteristics of being able to be prepared in low-temperature solutions, continuously adjustable band gap, and high defect tolerance, making the PeLED produced by it an ideal candidate for luminescence and display applications, and is expected to develop a new full-color display with higher performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the structure of the stacked device of Example 1;

[0026] Figure 2 PL spectrum of the perovskite / GaN film in Example 1;

[0027] Figure 3 PLQE spectrum of the perovskite / GaN film in Example 1;

[0028] Figure 4 is the absorption spectrum of the perovskite / GaN film in Example 1;

[0029] Figure 5 This is a scanning electron microscope image of the perovskite / GaN film in Example 1;

[0030] Figure 6 is the external quantum efficiency-current density relationship curve of the stacked light-emitting device in Example 1;

[0031] Figure 7 is a current density-brightness-voltage relationship curve of the stacked light-emitting device in Example 1;

[0032] Figure 8 is an EL spectrum diagram of the stacked light-emitting device in Example 1;

[0033] Fig. 9 PL spectrum of the perovskite / GaN film in Example 2;

[0034] Fig.10 PLQE spectrum of the perovskite / GaN film in Example 2;

[0035] Fig.11 is the absorption spectrum of the perovskite / GaN film in Example 2;

[0036] Fig.12 This is a scanning electron microscope image of the perovskite / GaN film in Example 2;

[0037] Fig.13 is the external quantum efficiency-current density relationship curve of the stacked light-emitting device in Example 2;

[0038] Fig.14 is the current density-brightness-voltage relationship curve of the stacked light-emitting device in Example 2;

[0039] Fig.15 is an EL spectrum diagram of the stacked light-emitting device in Example 2;

[0040] Fig.16 This is the external quantum efficiency-current density relationship curve of the stacked light-emitting device in Comparative Example 1;

[0041] Fig.17 is the current density-brightness-voltage relationship curve of the stacked light-emitting device in comparative example 1;

[0042] Fig.18 EL spectrum of the stacked light-emitting device in Comparative Example 1;

[0043] Fig.19 This is the external quantum efficiency-current density relationship curve of the stacked light-emitting device in Comparative Example 2;

[0044] Fig. 20is the current density-brightness-voltage relationship curve of the stacked light-emitting device in comparative example 2;

[0045] Fig.21 EL spectrum of the stacked light-emitting device in Comparative Example 2;

[0046] Fig. 22 Schematic diagram of circuit control of the stacked device of Example 1;

[0047] Fig.23 The external quantum efficiency-current density relationship curve of the stacked device in Comparative Example 3;

[0048] Fig.24 is the brightness-voltage characteristic curve of the stacked device in Comparative Example 3;

[0049] Fig.25 This is the EL spectrum of the stacked device in Comparative Example 3. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with embodiments, but the description of the embodiments does not impose any limitation on the protection scope of the present invention.

[0051] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention, and the terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In addition, although a demonstration of parameters containing specific values ​​may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within an acceptable error tolerance or design constraint. The directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only referenced to the directions of the accompanying drawings. Therefore, the directional terms used are used to illustrate rather than to limit the scope of protection of the present invention.

[0052] Unless otherwise specified, the materials and instruments used in the following examples can be obtained from conventional commercial channels.

[0053] Example 1

[0054] Spin coating growth of green CsPbBr on blue GaN LED epiwafers 3 Perovskite film, combined with thermal evaporation process to prepare a two-color stacked perovskite / GaN stacked device, the device structure is: n-GaN / multiple quantum well / p-GaN / ITO / PEDOT:PSS / CsPbBr 3 / TPBi / LiF / Al, such as Figure 1 The steps for complete device preparation include:

[0055] Step 1: Select a high-quality blue light GaN LED epitaxial wafer with a smooth surface as a substrate.

[0056] Step 2, cleaning the substrate: placing the substrate in acetone, deionized water, and anhydrous ethanol in turn, ultrasonically treating for 10 minutes each to remove impurities, and then blowing the substrate dry with nitrogen for later use.

[0057] Step 3: Use PECVD technology to grow a layer of SiO on the surface of the substrate. 2 The growth conditions of the film are as follows: 5% SiH 4 / N 2 and N 2 O mixed gas, control a certain gas flow, keep the chamber pressure, temperature and power constant, and grow for a certain time. 2 The thickness of the thin film layer ranges from 100 to 500 nm, preferably from 300 to 400 nm; N 2 The O gas flow rate range is 200-500sccm, preferably 300-500sccm; 5% SiH 4 / N 2 The gas flow rate range is 50-200sccm, and the preferred flow rate is 100-200sccm; the chamber pressure range is 100-400mTorr, and the preferred pressure is 200-400mTorr; the temperature range is 100-400℃, and the preferred temperature is 200-300℃; the power range is 5-30W, and the preferred power is 5-20W; the growth time is 1-4min, and the preferred time is 2-4min.

[0058] Step 4, UV lithography and development: After the SiO is grown 2 The positive photoresist is spin-coated on the substrate of the thin film, and then pre-baked at a specific temperature for a period of time, and then the sample is exposed using an ultraviolet photolithography machine, and the exposed sample is placed in a positive photoresist developer for development, and finally post-baked at a specific temperature for a period of time to obtain the epitaxial wafer table pattern. The positive photoresist is AZ6130 positive photoresist, and the photopolymerization conditions are as follows: low speed is 400-800rpm, preferably 600rpm; time is 4-8s, preferably 6s; high speed is 3000-5000rpm, preferably 3000-4000rpm; time is 30-50s, preferably 30-40s; pre-baking temperature is 80-120℃, preferably 100-110℃; time is 1-4min, preferably 2-4min; exposure time is 2-3s, preferably 2-2.6s; development time is 40-120s, preferably 70-90s.

[0059] Step 5: Use RIE technology to etch the SiO2 not covered by the photoresist. 2, the etching conditions are as follows: the etching gas is CF 4 , the gas flow rate is 30sccm, the gas pressure is 4Pa, the power is 120W, and the etching time is 10-15min.

[0060] Step 6, cleaning the photoresist: place the sample in acetone and deionized water in turn, and heat it in a water bath at 50°C for 5 minutes.

[0061] Step 7, ITO etching: Soak the sample in ITO etching solution for 3 minutes to etch the uncoated SiO 2 The samples were then covered with ITO and cleaned in deionized water.

[0062] Step 8, etching GaN: Use ICP technology to etch the un-SiO 2 The etching conditions are as follows: the etching gas Cl 2 and BCl 3 , the gas flow rates were 48±4sccm and 6±2sccm respectively, the chamber pressure was 10±2mTorr, the RF power was 270±30W, the ICP power was 100±20W, and the etching time was 5-6min.

[0063] Step 9: Removal of SiO 2 :Put the sample in buffered oxide etchant (BOE) for 2-3 minutes to remove SiO 2 , and obtain a stepped ITO / n-GaN sample.

[0064] Step 10, using acetone, deionized water, and anhydrous ethanol to ultrasonically clean the sample, and then treating it with an oxygen plasma machine for later use.

[0065] Step 11, prepare a PEDOT:PSS film in an air environment using a spin coating process, and complete the film preparation by annealing. The coating conditions are as follows: the rotation speed is 3000-6000rpm, preferably the rotation speed is 5000rpm; the spin coating time is 30-50s, preferably the time is 45s; the annealing time is 10-20min, preferably 10min.

[0066] Step 12, transfer the sample to a nitrogen glove box, prepare the perovskite film by spin coating process, and complete the film preparation by annealing. The coating conditions are as follows: the rotation speed is 3000-6000rpm, preferably the rotation speed is 3000rpm; the spin coating time is 30-60s, preferably the time is 45s, and the annealing time is 10-20min, preferably 15min.

[0067] Step 13, transfer the perovskite film to a high vacuum deposition chamber, and use thermal evaporation technology to sequentially deposit TPBi, LiF and Al, with thicknesses of 40-60 nm, 0.8-1.4 nm and 80-120 nm, respectively.

[0068] like Fig. 22 As shown, two independently controlled power supplies are used to drive the device to emit light, wherein one end of one independent power supply is connected to the cathode on the n-GaN, and the other end is connected to the ITO layer to drive the multi-quantum well light-emitting structure; one end of the other independent power supply is connected to LiF / Al, and the other end is connected to the ITO layer to drive the perovskite light-emitting structure.

[0069] Green light-emitting CsPbBr grown on GaN / ITO 3 The photoluminescence spectrum of perovskite films is shown in Figure 2 As shown, the emission wavelength is 519nm; the photoluminescence quantum efficiency spectrum is as follows Figure 3 As shown in Figure 2, the highest PLQE value is 44.8%; the absorption spectrum is shown in Figure 2 Figure 4 As shown; scanning electron microscopy spectrum as shown Figure 5 As shown; the performance of the stacked light-emitting diode device based on the grown thin film is shown Figure 6 As shown, the maximum external quantum efficiency of blue and green LEDs are 6.7% and 8.0% respectively, and the maximum brightness is 91003cd / cm 2 、111956cd / cm 2 , see Figure 7 The device brightness-voltage characteristic curve, the device emission wavelengths are 457nm and 519nm respectively, see Figure 8 EL spectrum of .

[0070] Example 2

[0071] Example 2 Spin coating growth of red light CsPb(I) on blue light GaN LED epitaxial wafer 0.4 Br 0.6 ) 3 Perovskite film, and prepare a two-color stacked perovskite / GaN stacked device, the device structure is: n-GaN / multiple quantum well / p-GaN / ITO / PEDOT:PSS / PTAA / CsPb(I 0.4 Br 0.6 ) 3 / TPBi / LiF / Al. The preparation process of Example 2 is the same as that of Example 1, and the thickness of each layer is also the same. The differences between the two are mainly reflected in the following two aspects: first, the chemical components selected for the perovskite film are different; second, compared with Example 1, Example 2 adds an additional step, that is, a PTAA transport layer film is spin-coated and grown on the surface of the PEDOT:PSS layer, so as to optimize charge transfer, improve the luminous efficiency of the red light perovskite device, and enhance the device performance.

[0072] Red CsPb(I 0.4 Br 0.6 ) 3 The photoluminescence spectrum of perovskite films is shown in Fig. 9 As shown, the emission wavelength is 655nm; the photoluminescence quantum efficiency spectrum is as follows Fig.10 As shown in Figure 2, the highest PLQE value is 44.8%; the absorption spectrum is shown in Figure 2 Fig.11 As shown; scanning electron microscopy images are shown Fig.12 As shown; the performance of the stacked light-emitting diode device based on the grown thin film is shown Fig.13 As shown, the maximum external quantum efficiency of the red LED is 10.1%, and the maximum brightness is 1398cd / cm 2 , see Fig.14 The device brightness-voltage characteristic curve, the device emission wavelength is 655nm, see Fig.15 EL spectrum of .

[0073] Comparative Example 1

[0074] The device structure is: n-GaN / multiple quantum well / p-GaN / CsPb(I 0.4 Br 0.6 ) 3 / PTAA / LiF / Al. The steps for complete device preparation include:

[0075] Step 1: Select a high-quality blue light GaN LED epitaxial wafer with a smooth surface as a substrate.

[0076] Step 2, cleaning the substrate: placing the substrate in acetone, deionized water, and anhydrous ethanol in turn, ultrasonically treating for 10 minutes each to remove impurities, and then blowing the substrate dry with nitrogen for later use.

[0077] Step 3, spin-coat the positive photoresist on the substrate, then pre-bake it at a specific temperature for a period of time, then use a UV photolithography machine to expose the sample, put the exposed sample into a positive photoresist developer for development, and finally post-bake it at a specific temperature for a period of time to obtain the mesa pattern of the epitaxial wafer.

[0078] Step 4, etching GaN: Use ICP technology to etch the p-GaN layer in the area not covered by the photoresist, etching 40nm and 60nm respectively.

[0079] Step 5, cleaning the photoresist: place the sample in acetone and deionized water in turn, and heat in a water bath at 50°C for 5 minutes.

[0080] Step 6: Use PECVD technology to grow a layer of SiO on the surface of the substrate. 2 film.

[0081] Step 7, UV photolithography and development: After the SiO is grown 2 Positive resist is spin-coated on the thin film substrate, followed by pre-baking at a specific temperature for a period of time, and then the sample is exposed using a UV photolithography machine. The exposed sample is placed in a positive resist developer for development, and finally post-baked at a specific temperature for a period of time to obtain the mesa pattern of the epitaxial wafer.

[0082] Step 8: Use RIE technology to etch the SiO2 not covered by the photoresist. 2 .

[0083] Step 9, cleaning the photoresist: place the sample in acetone and deionized water in turn, and heat in a water bath at 50°C for 5 minutes.

[0084] Step 10, etching GaN: Use ICP technology to etch the GaN that is not covered by SiO 2 The covered area reaches the n-GaN layer.

[0085] Step 11, cleaning SiO 2 :Put the sample in BOE solution and soak for 2-3 minutes to remove SiO 2 , and obtain a stepped p-GaN / n-GaN sample.

[0086] Step 12, ultrasonically clean the sample using acetone, deionized water, and anhydrous ethanol for 10 minutes respectively, and then treat the sample with oxygen plasma for later use.

[0087] Step 13, prepare the perovskite film and the transport layer PTAA film in a nitrogen glove box using a spin coating process.

[0088] Step 14, transferring the sample to a high vacuum deposition chamber, and sequentially depositing LiF and Al using thermal evaporation technology.

[0089] The performance of the stacked device with this structure is as follows Fig.16 As shown in the figure, the p-GaN layer with different thicknesses was prepared, and the maximum external quantum efficiency of the device was 2.1%, 2.7% and 2.6%, respectively, and the device brightness was 10682cd / cm 2 、13599cd / cm 2and 13831cd / cm 2 , see Fig.17 The device brightness-voltage characteristic curve, in the device structure without ITO connecting layer, the perovskite and GaN layers emit light together, and the device emission wavelength is 462nm and 630nm, see Fig.18 EL spectrum of .

[0090] Comparative Example 2

[0091] The device structure is: n-GaN / multi-quantum well / p-GaN / ETL / CsPb(I 0.4 Br 0.6 ) 3 / PTAA / LiF / Al. The preparation process of comparative example 2 is the same as that of comparative example 1, except that a step is added, that is, a layer of electron transport layer thin film is grown by spin coating on the surface of p-GaN. The materials selected are PCBM, TPBi, SnO 2 Any one of .

[0092] The performance of the stacked device with this structure is as follows Fig.19 As shown, PCBM, TPBi, SnO 2 The maximum external quantum efficiency of the transport layer devices is 0.006%, 0.06% and 0.09% respectively, and the maximum brightness of the LED is 35cd / cm 2 、57cd / cm 2 and 207cd / cm 2 , see Fig. 20 The device brightness-voltage characteristic curve, the device emission wavelength see Fig.21 EL spectrum of .

[0093] Comparative Example 3

[0094] Comparative Example 3: Spin coating growth of green CsPbBr on blue GaN LED epitaxial wafer 3 Perovskite film, combined with thermal evaporation process to prepare a two-color stacked perovskite / GaN stacked device, the device structure is: n-GaN / multiple quantum well / p-GaN / ITO / ZnO / PEIE / CsPbBr 3 / TFB / MoO 3 / Ag, the preparation process and thickness of each layer of Comparative Example 1 are basically the same as those of Example 1, and the differences between the two are mainly reflected in the following two aspects: first, the upper layer of the perovskite is a hole transport layer, and the lower layer is an electron transport layer; second, the electrode is MoO 3 Modified Ag electrode.

[0095] The performance of the stacked device with this structure is as follows Fig.23 As shown, the maximum external quantum efficiency of the device is 3.8%, and the maximum brightness of the LED is 88089cd / cm2 , see Fig.24 The device brightness-voltage characteristic curve, the device emission wavelength see Fig.25 EL spectrum of .

[0096] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A multi-color stacked perovskite / GaN stacked device, characterized in that It includes the following structures arranged from bottom to top: n-type GaN layer, multi-quantum well layer, p-type GaN layer, ITO layer, hole transport layer, perovskite layer, electron transport layer, a cathode is arranged on the n-type GaN layer, and a cathode is arranged on the electron transport layer.

2. The multi-color stacked perovskite / GaN stacked device according to claim 1, characterized in that: It also includes a light-emitting control circuit, which includes two independently controlled power supplies, one end of which is connected to the cathode on the n-type GaN layer, and the other end is connected to the ITO layer to drive the multi-quantum well light-emitting structure; one end of the other independent power supply is connected to the cathode on the electron transport layer, and the other end is connected to the ITO layer to drive the perovskite light-emitting structure.

3. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The n-type GaN layer is GaN doped with silicon or aluminum, and has a thickness of 1-1.5 μm; the p-type GaN layer is GaN doped with Mg, and has a thickness of 70-100 nm.

4. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The multi-quantum well layer is an InGaN / GaN multi-quantum well structure.

5. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The hole transport layer is one or more of PEDOT:PSS, PVK, NiOx, PTAA or small molecule doped PEDOT:PSS, PEDOT:PSS / PTAA composite transport layer, and has a thickness of 30-50 nm.

6. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The electron transport layer is one or more of TPBi, TmPyPB or PO-T2T, and has a thickness of 40-60 nm.

7. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The chemical formula of the perovskite is L2(SMX3) n-1 MX4; wherein M is a divalent metal cation, L is a long-chain organic cation, S is a monovalent cation, X is any one or more of the halogen anions I, Br, and Cl, and n (n=1, 2, ..., ∞) is the number of semiconductor MX4 layers in the organic insulating layer. When n=∞, it is a 3D perovskite with a SMX3 structure.

8. The multi-color stacked perovskite / GaN stacked device according to claim 7, characterized in that The chemical formula of perovskite is CsPbBr3 or CsPb(Br x I 1-x )3.

9. The multi-color stacked perovskite / GaN stacked device according to claim 1 or 2, characterized in that: The cathode is Al, Ag, Au, or a LiF / Al layer modified by a LiF thin layer.

10. The method for preparing a multi-color stacked perovskite / GaN stacked device according to any one of claims 1 to 9, characterized in that The steps include: Step 1: Use PECVD technology to grow silicon dioxide on the ITO surface of the blue LED epitaxial wafer, then spin-coat photoresist on it and develop the pattern onto the photoresist; Step 2, using RIE technology, using photoresist as a mask, to carve out sample steps; Step 3, soaking the sample in ITO etching solution to remove the ITO layer under the step; soaking the sample in acetone solution to strip off the photoresist; Step 4, anisotropically etching the sample using ICP technology until the n-GaN layer is etched; Step 5, removing residual glue and silicon dioxide to obtain a sample with ITO / n-GaN steps; Step 6: clean and ultrasonicate the sample, blow dry it with nitrogen, prepare a hole transport layer, a perovskite layer, an electron transport layer and a cathode in sequence above the ITO layer of the sample, prepare a cathode on the exposed n-GaN layer, and finally obtain a multi-color stacked perovskite / GaN stacked device.

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