Photoelectric device with perovskite coaxial heterogeneous one-dimensional nanowire array and preparation method thereof

Abstract

The present invention discloses a photoelectric device having a perovskite coaxial heterogeneous one-dimensional nanowire array and a preparation method thereof. The photoelectric device comprises an electrode layer, a silicon dioxide substrate, and a perovskite coaxial heterogeneous one-dimensional nanowire array distributed on the silicon dioxide substrate; the perovskite coaxial heterogeneous one-dimensional nanowire is a core-shell structure; the core-shell structure has a molecular formula of A 1‑n B n The perovskite of CX3 is used as the core layer, with the molecular formula A 1‑n Cs n CY3 perovskite as shell; where 0≦n≦1, A is HC(NH2)2 + or CH3NH3 + , B is Cs + , C is Ge 2+ , Sn 2+ and Pb 2+ One of, X and Y are each independently one of Cl, Br and I, and X is different from Y. The optoelectronic device has a perovskite coaxial heterogeneous one-dimensional nanowire array, and its perovskite can form a heterojunction, which is beneficial to the transmission of electrons and holes, thereby improving the switching ratio and responsiveness of the optoelectronic device.

Description

Technical Field

[0001] The present invention relates to the field of microelectronic devices, and in particular to a photoelectric device having a perovskite coaxial heterogeneous one-dimensional nanowire array and a preparation method thereof. Background Art

[0002] Organic-inorganic hybrid metal-halide perovskites have attracted wide attention in the optoelectronic fields such as solar cells, light-emitting diodes, and photodetectors due to their advantages such as ultra-long carrier diffusion length, adjustable band gap, large absorption coefficient, high carrier mobility, and solution processing capability. Compared with disordered structures, ordered one-dimensional nanowire arrays have the advantages of fewer defects and easy integration, and thus have better optoelectronic properties. Compared with simple homogeneous rod-shaped nanowires, these nanomaterials with complex structures not only have application value in simple physics, but also have high application value in optics / electricity. Due to the special structure of coaxial heterogeneous one-dimensional nanomaterials, they have high research value in some special optical and electrical aspects, and therefore have attracted the attention of many scientific researchers. Coaxial nanowires are divided into two parts, core-shell, and a large and closed interface can be created between the two parts. Due to the existence of this interface, the stability of the internal materials can be protected first, and at the same time, the selection of suitable host-guest materials can achieve the enhancement of optical signals and higher energy conversion efficiency. The traditional photolithography method of preparing coaxial heterogeneous one-dimensional nanomaterials has a very complicated processing process and high preparation cost, which limits the large-scale application of perovskite one-dimensional arrays in the field of optoelectronic devices. In addition, due to the influence of the miscibility of perovskite heterojunction solvents, the development of perovskite coaxial heterogeneous nanowires is limited. Therefore, we urgently need to develop a simple, effective, low-cost and easy-to-operate method to realize the preparation of optoelectronic devices with perovskite coaxial heterogeneous one-dimensional nanowire arrays. Summary of the invention

[0003] The first object of the present invention is to provide an optoelectronic device having a perovskite coaxial heterogeneous one-dimensional nanowire array.

[0004] The second object of the present invention is to provide a preparation method of an optoelectronic device with a perovskite coaxial heterostructure one-dimensional nanowire array. The core of this preparation method lies in the co-synthesis of a perovskite coaxial heterostructure one-dimensional nanowire array by combining a superwetting self-assembly technique and an ion-exchange method. Specifically, through the dewetting induction of microstructured silicon pillars, the position and shape of the precursor perovskite one-dimensional array can be precisely regulated, which is beneficial to the subsequent integration of devices. In addition, through the ion-exchange method, the halogens in the precursor perovskite one-dimensional nanowire array are exchanged. Among them, by controlling the exchange time, perovskite coaxial heterostructure one-dimensional nanowire arrays (core-shell structure one-dimensional nanowire arrays) with different halogen ratios can be obtained, and various perovskite core-shell structure one-dimensional nanowire arrays with different compositions can also be obtained by controlling the types of halogens. The perovskite one-dimensional nanowire array obtained by the preparation method of the present invention has a smooth and uniform surface and fewer defects, which is beneficial to the improvement of the stability and responsivity of optoelectronic devices.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides an optoelectronic device with a perovskite coaxial heterostructure one-dimensional nanowire array, including an electrode layer, a silicon dioxide substrate, and a perovskite coaxial heterostructure one-dimensional nanowire array distributed on the silicon dioxide substrate;

[0007] The perovskite coaxial heterostructure one-dimensional nanowire has a core-shell structure; the core-shell structure uses a perovskite with the molecular formula A 1-n B n CX3 as the core layer and a perovskite with the molecular formula A 1-n B n CY3 as the shell layer; where 0≦n≦1, A is HC(NH2)2 + or CH3NH3 + , B is Cs + , C is Ge 2+ , Sn 2+ and Pb 2+ one of them, X and Y are each independently one of Cl, Br, and I, and X and Y are different.

[0008] According to the specific embodiments of the present invention, the value range of n can be 0 < n≦1, 0≦n < 1, 0 < n < 1, etc.

[0009] Further, the electrode layer includes a chromium layer with a thickness of 10-30 nm and a gold layer with a thickness of 80-100 nm.

[0010] Further, the width of the nanowires in the perovskite coaxial heterostructure one-dimensional nanowire array is 1-5 μm, the height is 100-500 nm, and the distance between adjacent nanowires is 2-5 μm.

[0011] According to a specific embodiment of the present invention, the width of the nanowires of the perovskite coaxial heterogeneous one-dimensional nanowire array is affected by the width of the template, including but not limited to 1-2 μm, 2-3 μm, 3-4 μm, 2-4 μm, 4-5 μm, etc. The height of the nanowires of the perovskite coaxial heterogeneous one-dimensional nanowire array is mainly determined by various experimental parameters in the preparation process.

[0012] It should be noted that the nanowires in the coaxial heterogeneous one-dimensional nanowire array of perovskite distributed on the silicon dioxide substrate in the present invention are core-shell structures, wherein the structure of the shell layer is more stable and can protect the core layer; however, when the core layer itself is an extremely unstable halide-containing perovskite, such as APbI3, it is unstable at room temperature and transforms from the δ phase to the α phase by heating, but automatically transforms into the δ phase after being placed at room temperature for a period of time. The present invention firstly dopes Cs ions so that the APbI3 that undergoes phase transformation due to heating can remain in the α phase for a long time even when the room temperature is restored, and then synthesizes a more stable shell layer on the surface of APbI3 by ion exchange, thereby increasing the stability of the core layer (APbI3) again.

[0013] In a second aspect, the present invention provides a method for preparing an optoelectronic device having a perovskite coaxial heterogeneous one-dimensional nanowire array, comprising the following steps:

[0014] (1) Add a molecular formula A on the template surface 1-n B n A perovskite precursor solution of CX3 is then coated with a silicon dioxide substrate to form a sandwich structure, and then dried to evaporate the solvent to obtain a silicon dioxide substrate with a one-dimensional perovskite nanowire array distributed thereon;

[0015] (2) immersing the silica substrate with the one-dimensional perovskite nanowire array facing upward in a halogen Y ion source solution to perform ion exchange, followed by washing and heating to obtain a silica substrate with the one-dimensional perovskite nanowire array distributed thereon;

[0016] (3) depositing an electrode layer on the surface of the perovskite coaxial heterogeneous one-dimensional nanowire array to obtain;

[0017] Wherein, X and Y are each independently one of Cl, Br and I, and X and Y are different.

[0018] Further, in the above method, in step (1), the molecular formula is: A 1-n B n The solvent of the perovskite precursor solution of CX3 is selected from one or both of super-dry dimethyl sulfoxide and super-dry N,N-dimethylformamide.

[0019] The concentration of the perovskite precursor solution is 10-30 mg / mL. The present invention finds that the concentration of the perovskite precursor solution affects the parameters of the final nanowires. When the concentration of the perovskite precursor solution is not within the range of the present invention, the width may be too large or the one-dimensional nanowires formed may have more surface defects or even fail to form a one-dimensional array.

[0020] The drying condition is: the temperature is 50-100°C. The present invention finds that the drying temperature within the range of the present invention can ensure the continuity and smoothness of the one-dimensional nanowires. If the temperature is too high, the one-dimensional nanowires will be intermittent, the crystallization performance will deteriorate or the one-dimensional nanowire structure will not grow at all. If the temperature is too low, the required drying time, i.e., the dewetting time, will be too long, which is not conducive to the formation of smooth one-dimensional nanowires.

[0021] In step (2), the halogen Y ion source is one of oleylamine chloride, oleylamine bromide and oleylamine iodine; preferably, the concentration of the halogen Y ion source solution is 1-10 mg / mL.

[0022] The conditions of the ion exchange are: room temperature and 24 hours. The present invention first prepares halogen-containing perovskite nanowires by infiltration self-assembly technology, and then immerses them in solutions of different halogen ion sources. By controlling the exchange time and temperature, perovskite nanowires with core-shell structures containing different halogen components can be obtained.

[0023] The heating conditions are: temperature of 25-165°C and time of 0.5-2 hours. It should be noted that the selection of the heating temperature and time is actually divided into two situations. First, when the structure of the selected perovskite precursor (i.e., core layer perovskite) itself is relatively stable, it only needs to be heated until the solvent evaporates completely. At this time, the heating temperature can be selected within the range as needed; second, when the structure of the selected perovskite itself is an unstable δ phase, the purpose of heating is not only to evaporate the solvent, but also to cause a phase change process in the δ phase. At this time, the heating should be carried out at 165°C for at least 15-60 minutes. After heating under this condition, the perovskite will be converted from the δ phase to the stable α phase. The perovskite one-dimensional nanowire array converted to the α phase has better photoelectric properties, which is more conducive to the improvement of the photoelectric performance of the photoelectric device.

[0024] In a specific application process, the template is preferably a silicon column template with a micro-column structure (such as Figure 1 As shown in FIG. 1 , the manufacturing process is as follows: using photolithography technology to prepare a silicon pillar array structure. At this time, the size and spacing distribution of the silicon pillars in the prepared silicon pillar array structure will affect the distribution of the coaxial heterogeneous one-dimensional nanowire array of the perovskite on the subsequent optoelectronic device. Therefore, during the setting, the silicon pillar array structure can be prepared according to different requirements.

[0025] The prepared silicon column template needs to be treated with asymmetric wetting. For example, the specific steps are as follows: a. First, treat the surface of the silicon column with oxygen plasma to make the surface of the silicon column hydrophilic; b. Spin-coat the photoresist SU8 on the glass substrate, and then turn the silicon column template upside down on the glass substrate; c. Make the photoresist adhere to the top of the silicon column on the template to form a protective layer; d. Put the silicon column template and fluorosilane into a vacuum dryer for high-temperature reaction, and the vaporized fluorosilane molecules will adhere to the surface of the silicon column template, making the surface of the silicon column template hydrophobic; e. Use acetone to wash away the photoresist on the top of the silicon column, so that the hydrophilic top of the silicon column is exposed.

[0026] In addition, it should be noted that, unless otherwise specified, any range described in the present invention includes the end values ​​and any numerical values ​​between the end values ​​and any sub-range formed by the end values ​​or any numerical values ​​between the end values.

[0027] Beneficial effects of the present invention

[0028] The perovskite coaxial heterogeneous one-dimensional nanowire array of the optoelectronic device provided by the present invention has a smooth and uniform surface and fewer defects. The perovskite can form a heterojunction, which is beneficial to the transmission of electrons and holes, thereby improving the switching ratio and responsiveness of the optoelectronic device.

[0029] In the optoelectronic device with the coaxial heterogeneous one-dimensional perovskite nanowire array provided by the present invention, the perovskite nanowire is a core-shell structure, wherein the structure of the shell layer is more stable and plays a role in protecting the core layer. Secondly, the present invention finds that the stability of the core layer can be further increased by doping Cs ions.

[0030] The preparation method provided by the present invention controls the dewetting induction of the microstructured silicon pillars and the ion exchange method so that the position, shape and composition of the obtained perovskite coaxial heterogeneous one-dimensional nanowire array can be adjusted as needed to meet the optoelectronic devices with different needs.

[0031] The preparation method provided by the invention is simple, effective, low-cost and suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A scanning electron microscope photograph of the template used in the present invention is shown.

[0033] Figure 2 A scanning electron microscope photograph of the perovskite one-dimensional nanowire array of Example 1 is shown.

[0034] Figure 3 A schematic diagram showing the internal structure of the perovskite one-dimensional nanowire array of Example 1.

[0035] Figure 4A schematic diagram showing an optoelectronic device having a perovskite coaxial heterogeneous one-dimensional nanowire array according to Example 1.

[0036] Figure 5 The IV curve of the optoelectronic device having the perovskite coaxial heterogeneous one-dimensional nanowire array of Example 1 is shown.

[0037] Figure 6 The graph shows the variation trend of the photocurrent and the response of the optoelectronic device with the perovskite coaxial heterogeneous one-dimensional nanowire array of Example 1 as the incident light power changes.

[0038] Figure 7 The XRD comparison spectra of the perovskite one-dimensional nanowire arrays of different compositions in the comparative example are shown on the same day and after being placed at room temperature for 11 days.

[0039] Figure 8 The IV curve comparison diagram of the photovoltaic devices with different compositions of the comparative example is shown.

[0040] Fig. 9 A comparison diagram of the changing trend curves of the photocurrent and the responsivity of the optoelectronic devices of different compositions in the comparative example as the incident light power changes is shown. DETAILED DESCRIPTION

[0041] The present invention is described in detail below by way of examples. It is necessary to point out that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0042] Example 1

[0043] Preparation of a coaxial heterogeneous one-dimensional nanowire array perovskite optoelectronic device with a core layer of (HC(NH2)2) 0.9 Cs 0.1 PbI3, shell is (HC(NH2)2) 0.9 Cs 0.1 PbBr3). It comprises the following steps:

[0044] (1) using photolithography to prepare a silicon pillar template, where the silicon pillar has a width of 2 μm and a spacing of 5 μm;

[0045] (2) Add 10 μL of the prepared (HC(NH2)2) 0.9 Cs 0.1 The precursor solution of PbI3 (HC(NH2)2 + and Cs +The molar ratio of 9:1, the concentration of 30 mg / mL, and the solvent was ultra-dry dimethyl sulfoxide) were dripped on the surface of the silicon column, and the silicon dioxide substrate cleaned with ethanol, acetone and isopropanol was covered to form a sandwich structure. The structure was heated at 70°C in a drying oven in an argon-filled glove box for 8 hours to obtain a silicon dioxide substrate (such as Figure 2 and 3 );

[0046] (3) The silica substrate with the perovskite one-dimensional nanowire array distributed thereon obtained in step (2) is placed with the front side facing upward, immersed in a solution containing bromide ions (the solvent is a mixture of 1 mg oleylamine bromide and 10 mL 1-octadecene), ion exchange is performed at room temperature for 24 hours, and then rinsed three times with anhydrous chlorobenzene and anhydrous n-hexane, and heated at 165° C. for 1 hour to obtain a silica substrate with the perovskite coaxial heterogeneous one-dimensional nanowire array distributed thereon, wherein the core layer of the perovskite coaxial heterogeneous one-dimensional nanowire array is (HC(NH2)2) 0.9 Cs 0.1 PbI3, shell is (HC(NH2)2) 0.9 Cs 0.1 PbBr3, height 100-500nm;

[0047] (4) Using a copper mesh as a mask, 10 nm of chromium is sputtered on the perovskite coaxial heterogeneous one-dimensional nanowire array, and then 100 nm of gold is sputtered as an electrode, and finally a photoelectric device (photodetector) having a perovskite coaxial heterogeneous one-dimensional nanowire array is obtained (such as Figure 4 ).

[0048] from Figure 5 and Figure 6 It can be seen that the switching ratio of the photoelectric device can reach 5.2×10 5 , the response can reach 2551A w -1 .

[0049] Example 2

[0050] Preparation of a coaxial heterogeneous one-dimensional nanowire array perovskite optoelectronic device (core layer is (HC(NH2)2) 0.9 Cs 0.1 PbI3, shell is (HC(NH2)2) 0.9 Cs 0.1 PbCl3), comprising the steps of:

[0051] (1) A silicon pillar template was prepared by photolithography, with a silicon pillar width of 2 μm and a spacing of 5 μm.

[0052] (2) Add 10 μL of the prepared precursor solution (HC(NH2)2) 0.9 Cs0.1 PbI3(HC(NH2)2 + and Cs + The molar ratio of 2-hydroxy-1-nitropropene to 2-hydroxy-1-nitropropene is 9:1, the concentration is 30 mg / mL, and the solvent is ultra-dry dimethyl sulfoxide), which is dripped on the surface of the silicon column, and covered with a silica substrate cleaned with ethanol, acetone and isopropanol to form a sandwich structure, which is heated at 70°C for 8 hours in a drying oven in an argon-filled glove box to obtain a silica substrate with a perovskite one-dimensional nanowire array distributed thereon;

[0053] (3) The silica substrate with the perovskite one-dimensional nanowire array distributed thereon obtained in step (2) is placed with the front side facing upward, immersed in a solution containing chloride ions (the solvent is a mixture of 1 mg oleylamine bromide and 10 mL 1-octadecene), ion exchange is performed at room temperature for 24 hours, and then rinsed three times with anhydrous chlorobenzene and anhydrous n-hexane, and heated at 165° C. for 1 hour to obtain a silica substrate with the perovskite coaxial heterogeneous one-dimensional nanowire array distributed thereon, wherein the core layer of the perovskite coaxial heterogeneous one-dimensional nanowire array is (HC(NH2)2) 0.9 Cs 0.1 PbI3, shell is (HC(NH2)2) 0.9 Cs 0.1 PbCl3, height 100-500nm.

[0054] (4) Using a copper mesh as a mask, 10 nm of chromium is sputtered on the perovskite coaxial heterogeneous one-dimensional nanowire array, and then 100 nm of gold is sputtered as an electrode, and finally a photoelectric device (photodetector) with a perovskite coaxial heterogeneous one-dimensional nanowire array is obtained.

[0055] The switching ratio and responsiveness of the photoelectric device are basically the same as those in Example 1.

[0056] Example 3

[0057] A coaxial heterogeneous one-dimensional nanowire array perovskite photoelectric device (core layer is CsPbI3, shell layer is CsPbBr3) is prepared, comprising the following steps:

[0058] (1) A silicon pillar template is prepared by photolithography, wherein the silicon pillar has a width of 2 μm and a spacing of 5 μm;

[0059] (2) 10 μL of the prepared precursor solution CsPbI3 (the molar ratio of CsI and PbI2 is 1:1, the concentration is 30 mg / mL, and the solvent is ultra-dry dimethyl sulfoxide) is dripped onto the surface of the silicon column, and the silicon dioxide substrate cleaned with ethanol, acetone and isopropanol is covered to form a sandwich structure, which is heated at 70 °C in a drying oven in an argon-filled glove box for 8 h;

[0060] (3) placing the silica substrate with the perovskite one-dimensional nanowire array distributed thereon obtained in step (2) with the front side facing upward, immersing it in a solution containing bromide ions (the solvent is a mixture of 1 mg oleylamine bromide and 10 mL 1-octadecene), exchanging ions at room temperature for 24 hours, then rinsing it three times with anhydrous chlorobenzene and anhydrous n-hexane, and heating it at 165° C. for 1 hour to obtain a silica substrate with a perovskite coaxial heterogeneous one-dimensional nanowire array distributed thereon, wherein the perovskite is coaxial heterogeneous, the core layer is CsPbI3, the shell layer is CsPbBr3, and the height is 100-500 nm;

[0061] (4) Using a copper mesh as a mask, 10 nm of chromium is sputtered on the perovskite coaxial heterogeneous one-dimensional nanowire array, and then 100 nm of gold is sputtered as an electrode, and finally a photoelectric device (photodetector) with a perovskite coaxial heterogeneous one-dimensional nanowire array is obtained.

[0062] Some comparative examples

[0063] A series of one-dimensional nanowire arrays of perovskite optoelectronic devices were prepared. The specific steps are as follows:

[0064] (1) using photolithography to prepare a silicon pillar template, where the silicon pillar has a width of 2 μm and a spacing of 5 μm;

[0065] (2) 10 μL of a 30 mg / mL perovskite precursor solution (the perovskite is selected from one of those shown in Table 1) with a solvent of ultra-dry dimethyl sulfoxide was dripped onto the surface of the silicon column, and the silicon dioxide substrate cleaned with ethanol, acetone and isopropanol was covered to form a sandwich structure, which was heated at 165° C. for 1 hour in a drying oven in an argon-filled glove box to obtain a silicon dioxide substrate with a perovskite one-dimensional nanowire array distributed thereon, wherein the array height was 100-500 nm;

[0066] (3) Using a copper mesh as a mask, 10 nm of chromium was sputtered on the perovskite coaxial heterogeneous one-dimensional nanowire array, and then 100 nm of gold was sputtered as an electrode, and finally a photoelectric device (photodetector) with a perovskite one-dimensional nanowire array was obtained.

[0067] Table 1 Composition and abbreviation of perovskite of one-dimensional nanowire array

[0068]

[0069] Summary: From Figure 7It can be seen that in the comparative example, the perovskite one-dimensional nanowire array without Cs ion doping, such as HC(NH2)2PbI3, is completely decomposed into PbI2 after being placed for 11 days; the perovskite one-dimensional nanowire array doped with a certain proportion of Cs ions is partially converted into the δ phase or basically remains in the α phase after being placed for 11 days. It can be seen that doping with Cs ions can enhance the stability of perovskite, and the doping ratio of HC(NH2)2 + When the density is 1 / 9 of that of the quartz crystal, the stability of the perovskite is the best.

[0070] from Figure 8 It can be seen that doping with Cs ions can increase the photocurrent of perovskite photoelectric devices, among which the photocurrent of the photoelectric device with Cs10 is the highest.

[0071] from Fig. 9 It can be seen that doping with Cs ions can improve the responsivity of perovskite photoelectric devices. Among them, the photoelectric device with Cs10 has the largest responsivity, which is about 89A w -1 .

[0072] Secondly, we used Cs10 with the best effect as the core layer and prepared the optoelectronic device with perovskite coaxial heterogeneous one-dimensional nanowire array of Example 1 by ion exchange. Figure 6 and Fig. 9 It can be seen that the optoelectronic device with coaxial heterogeneous perovskite one-dimensional nanowire array in Example 1 has a higher responsiveness than the optoelectronic device with perovskite one-dimensional nanowire array in the comparative example, because the coaxial heterogeneous perovskite (core-shell structured perovskite) can form a Type II heterojunction, which is more conducive to the transmission of electrons and holes. Similarly, Examples 2 and 3 also have coaxial heterogeneous perovskites (core-shell structured perovskites) that can also form heterojunctions, so the responsiveness of their optoelectronic devices is higher than that of the optoelectronic device in the comparative example.

[0073] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing an optoelectronic device having a perovskite coaxial heterogeneous one-dimensional nanowire array, characterized in that: The following steps are involved: (1) Add a molecular formula A on the template surface 1-n B n A perovskite precursor solution of CX3 is then coated with a silicon dioxide substrate to form a sandwich structure, and then dried to evaporate the solvent to obtain a silicon dioxide substrate with a one-dimensional perovskite nanowire array distributed thereon; (2) immersing the silica substrate with the one-dimensional perovskite nanowire array facing upward in a halogen Y ion source solution to perform ion exchange, followed by washing and heating to obtain a silica substrate with the one-dimensional perovskite nanowire array distributed thereon; (3) depositing an electrode layer on the surface of the perovskite coaxial heterogeneous one-dimensional nanowire array; Wherein, the perovskite coaxial heterogeneous one-dimensional nanowire is a core-shell structure; the core-shell structure has a molecular formula of A 1-n B n The perovskite of CX3 is used as the core layer, with the molecular formula A 1-n B n CY3 perovskite as shell; where 0≦n≦1, A is HC(NH2)2 + or CH3NH3 + , B is Cs + , C is Ge 2+ , Sn 2+ and Pb 2+ wherein X and Y are each independently one of Cl, Br and I, and X and Y are different; In step (2), the halogen Y ion source is one of oleylamine chloride, oleylamine bromide and oleylamine iodine; The concentration of the halogen Y ion source solution is 1-10 mg / mL; In step (2), the ion exchange conditions are: the temperature is room temperature, and the time is 12-48 hours.

2. The preparation method according to claim 1, characterized in that: In step (1), the solvent of the perovskite precursor solution is selected from one or both of super-dry dimethyl sulfoxide and super-dry N,N-dimethylformamide.

3. The preparation method according to claim 1, characterized in that: In step (1), the concentration of the perovskite precursor solution is 10-30 mg / mL.

4. The preparation method according to claim 1, characterized in that: In step (1), the drying condition is: the temperature is 50-100°C.

5. The preparation method according to claim 1, characterized in that: In step (2), the heating conditions are: temperature of 25-165° C. and time of 0.5-2 hours.

6. An optoelectronic device having a perovskite coaxial heterogeneous one-dimensional nanowire array, characterized in that: Prepared by the preparation method according to any one of claims 1 to 5; It includes an electrode layer, a silicon dioxide substrate, and a perovskite coaxial heterogeneous one-dimensional nanowire array distributed on the silicon dioxide substrate; The perovskite coaxial heterogeneous one-dimensional nanowire is a core-shell structure; the core-shell structure has a molecular formula of A 1-n B n The perovskite of CX3 is used as the core layer, with the molecular formula A 1-n B n CY3 perovskite as shell; where 0≦n≦1, A is HC(NH2)2 + or CH3NH3 + , B is Cs + , C is Ge 2+ , Sn 2+ and Pb 2+ wherein X and Y are each independently one of Cl, Br and I, and X and Y are different.

7. The optoelectronic device according to claim 6, characterized in that: The electrode layer includes a chromium layer with a thickness of 10-30 nm and a gold layer with a thickness of 80-100 nm.

8. The optoelectronic device according to claim 6, characterized in that: The nanowires of the perovskite coaxial heterogeneous one-dimensional nanowire array have a width of 1-5 μm, a height of 100-500 nm, and a spacing between adjacent nanowires of 2-5 μm.

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