An organic heterojunction nanowire array, a preparation method thereof, and an optoelectronic device

Abstract

The present invention discloses an organic heterojunction nanowire array, a preparation method thereof, and an optoelectronic device. The preparation method includes: preparing a nanoscale channel array on the surface of a substrate, and then performing a hydrophobic treatment on the surface; by means of a first mask plate having a first through-hole array, preparing a metal phthalocyanine nanowire array on the surface by physical vapor deposition; and then by means of a second mask plate having a second through-hole array, preparing an aluminum tris(8-hydroxyquinoline) nanowire array on the surface by physical vapor deposition, wherein the second through-hole array is used to control the growth region of the aluminum tris(8-hydroxyquinoline) nanowire array, so that the aluminum tris(8-hydroxyquinoline) nanowire array overlaps with the metal phthalocyanine nanowire array, and an organic heterojunction nanowire array is prepared. This preparation method can achieve the directional growth and alignment of organic heterojunction nanowires, and further can achieve the in-situ large-scale construction and integration of nanowire device arrays.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and particularly to an organic heterojunction nanowire array, a preparation method thereof, and an optoelectronic device. Background Art

[0002] Organic heteronanowires provide a special material platform for studying physical processes such as charge generation, injection, transport, and optoelectronic conversion, developing micro-nano devices, and the interconnection between such devices, and have important research significance in the fields of modern electronics and photonics. More importantly, the structure containing two or more functional materials and the unique heterojunction interface may enhance the original performance or even generate new special properties. Compared with inorganic materials, organic semiconductors including organic small molecules and polymers have characteristics such as light weight, low cost, and adjustable molecular design. Based on these characteristics, great efforts have been made in the synthesis and preparation of one-dimensional organic p-n heterojunctions in recent years to promote their applications in next-generation organic micro-nano electronics and photonics. In addition, the organic heteronanowire structure also has a large specific surface area, and its heterojunction interface helps to enhance the separation and collection efficiency of carriers to develop high-performance compact optoelectronic devices.

[0003] To fabricate organic heteronanowire optoelectronic devices in batches, the primary task is to obtain an organic heteronanowire array. Currently, the mainstream method for preparing an organic heteronanowire array is to first synthesize the required heteronanowires by a solution method, and then obtain a nanowire horizontal array through processes such as secondary substrate transfer and alignment. The nanowires grown by the above solution method are disordered, and thus the position of the nanowire heterojunction cannot be accurately located, and it is even impossible to realize the in-situ large-scale fabrication and integration of nanowire devices. Moreover, the solvents and by-products used in the preparation process are likely to cause uncontrollable pollution to the nanowires, which will affect the performance of the nanowire devices. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an organic heterojunction nanowire array, a preparation method thereof, and an optoelectronic device. The preparation method can realize the directional growth and alignment of organic heterojunction nanowires, and can realize the in-situ large-scale fabrication and integration of nanowire device arrays.

[0005] In a first aspect of the present invention, a preparation method of an organic heterojunction nanowire array is provided, including the following steps:

[0006] S1. Prepare a nanoscale channel array on the surface of a substrate;

[0007] S2. Perform a hydrophobic treatment on the surface;

[0008] S3. By means of a first mask plate having a first through-hole array, a metal phthalocyanine nanowire array is prepared on the surface by physical vapor deposition;

[0009] S4. By means of a second mask plate having a second through-hole array, an aluminum tris(8-hydroxyquinoline) nanowire array is prepared on the surface by physical vapor deposition, wherein the second through-hole array is used to control the growth region of the aluminum tris(8-hydroxyquinoline) nanowire array, so that the aluminum tris(8-hydroxyquinoline) nanowire array overlaps with the metal phthalocyanine nanowire array, and an organic heterojunction nanowire array is prepared.

[0010] The preparation method of the organic heterojunction nanowire array according to the embodiment of the present invention has at least the following beneficial effects: in this preparation method, a nanoscale channel array is first prepared on the surface of a substrate and subjected to a hydrophobic treatment, and then, by means of a first mask plate having a first through-hole array, a metal phthalocyanine nanowire array is prepared on the surface of the substrate with a hydrophobic treatment and having a nanoscale channel array by physical vapor deposition. Among them, the nanoscale channel array on the surface of the substrate with a hydrophobic treatment during the physical vapor deposition process can guide the directional and orderly growth of the metal phthalocyanine nanowires, and the patterned metal phthalocyanine nanowire array can be prepared through the first through-hole array on the first mask plate; then, by means of a second mask plate having a second through-hole array, an aluminum tris(8-hydroxyquinoline) nanowire array connected to the metal phthalocyanine nanowire array is prepared on the surface of the substrate with a hydrophobic treatment and having a nanoscale channel array by physical vapor deposition to form an organic heterojunction nanowire array. Among them, the growth region of the aluminum tris(8-hydroxyquinoline) nanowire array can be controlled through the second mask plate and the second through-hole array thereon to achieve the positioning and alignment of the organic heterojunction nanowires, and the nanoscale channel array on the surface of the substrate during the physical vapor deposition process can guide the directional and orderly growth of the aluminum tris(8-hydroxyquinoline) nanowires thereon. Therefore, this preparation method can realize the directional growth and alignment of the organic heterojunction nanowires, and further realize the in-situ large-scale construction and integration of the nanowire device array; among them, the product organic heterojunction nanowire array is prepared by secondary growth through the physical vapor deposition method, without involving transfer solutions, and the growth operation is controllable and pollution-free.

[0011] In some embodiments of the present invention, the nanoscale channel array is a V-shaped nanoscale channel array with a width of 50-150 nm and a depth of 10-30 nm. After research, the directional growth of nanowires can be realized under such channel dimensions. If the channel width is too narrow or the depth is too shallow, it will not be sufficient to guide the directional growth of nanowires, and if the channel is too wide, micron wires will be formed or the guiding effect will be lost.

[0012] In some embodiments of the present invention, in step S1, an M-plane sapphire substrate may be used. Additionally, annealing treatment may be performed on the M-plane sapphire to form a nano-channel array on its surface. The temperature of the annealing treatment may be controlled within the range of 1550 - 1650 °C, and the annealing time may be controlled within the range of 9 - 10 h. Specifically, the M-plane sapphire (i.e., α-Al2O3, crystal plane orientation After high-temperature annealing, its surface will be along The direction forms a parallel array of "V"-shaped nano-channels with a width of approximately 50 - 150 nm and a depth of approximately 10 - 30 nm. By using the M-plane sapphire as the substrate, nano-scale channels can be directly generated through annealing treatment. Coupled with hydrophobic treatment, subsequent nanowire growth can be good, with high controllability and a simple process.

[0013] In addition, before annealing the M-plane sapphire, the M-plane sapphire can be cleaned first to remove surface oil stains. After the annealing treatment, the sapphire substrate obtained from the annealing treatment is cleaned again and then dried. The cleaning can specifically be performed by ultrasonic cleaning with cleaning liquids such as acetone, ethanol, and deionized water. The ultrasonic cleaning time can be controlled within the range of 5 - 15 min, preferably 8 - 10 min. The drying can specifically be performed by blowing dry with dry nitrogen.

[0014] In some embodiments of the present invention, the first mask and the second mask are respectively fixed on the surface of the substrate through a fixing device. The fixing device can be designed to have a fixing groove. Specifically, the fixing groove can include a substrate fixing groove and a mask fixing groove sequentially arranged in the extending direction from the bottom to the top of the fixing groove. The sizes of the substrate and the mask can be set to be respectively adapted to the sizes of the substrate fixing groove and the mask fixing groove, so that the substrate and the mask can be respectively clamped and fixed through the substrate fixing groove and the mask fixing groove. In step S3, an adhesive can be used to bond and fix the substrate in the substrate fixing groove of the fixing device, and then the first mask is placed in the mask fixing groove on the substrate, so that the first mask is disposed on the surface of the substrate through the fixing device. Similarly, in step S4, the first mask can be removed from the mask fixing groove first, and then the second mask is replaced, so that the second mask is disposed on the surface of the substrate through the fixing device. The adhesive can be polyvinyl alcohol (PAV). Specifically, an aqueous solution of polyvinyl alcohol can be used. During operation, it is covered on the bottom of the substrate fixing groove, then the substrate is placed in the mask fixing groove, and then the fixing device is placed on a heating table and heated until the substrate is firmly bonded in the substrate fixing groove.

[0015] In some embodiments of the present invention, in step S4, the second mask is fixedly disposed on the surface of the substrate by the fixing device, which includes: removing the first mask, and then replacing it with the second mask. The through holes on the second mask partially coincide with the metal phthalocyanine nanowire array, so that the tris(8-hydroxyquinoline)aluminum nanowire array prepared by physical vapor deposition is connected to the metal phthalocyanine nanowire array to form an organic heterojunction nanowire array. The first mask is configured to assist in the preparation of the metal phthalocyanine nanowire array, so the first through hole array thereon corresponds to the target metal phthalocyanine nanowire array; the second mask is configured to assist the tris(8-hydroxyquinoline)aluminum nanowire array, so the second through hole array thereon corresponds to the target tris(8-hydroxyquinoline)aluminum nanowire array. Therefore, the structures of the first mask and the second mask can be set according to the target nanowire array. The second through hole array on the second mask can be designed to be the same as the first through hole array on the first mask; or different, but the positions correspond. Specifically, the first mask and the second mask are designed according to the heterojunction alignment length. For example, the structure of the second mask can be the same as that of the first mask. In step S4, when the first mask is removed and the second mask is replaced, the position of the second through hole array on the second mask can be offset by a certain distance relative to the first through hole array of the first mask, so that the first mask partially coincides with the metal phthalocyanine nanowire array. Specifically, for example, the through hole sizes in the through hole arrays on the first mask and the second mask are both 200×200 μm, and the through hole pitch is 400 μm; in step S4, when the first mask is removed and the second mask is replaced, the position of the second through hole array on the second mask is shifted 100 μm to the right relative to the position of the first through hole array on the original first mask, so that the overlapping part of the first mask and the metal phthalocyanine nanowire array is 100 μm, which is equivalent to the overlapping part of the heterojunction being 100 μm.

[0016] In some embodiments of the present invention, in steps S3 and S4, the physical vapor deposition is carried out by vacuum evaporation.

[0017] In some embodiments of the present invention, in step S3, the source region temperature of the physical vapor deposition is 440°C to 480°C, preferably 440°C to 460°C; the growth region temperature is 240°C to 280°C, preferably 240°C to 250°C.

[0018] In some embodiments of the present invention, in step S4, the source region temperature of the physical vapor deposition is 320°C to 380°C, preferably 340°C to 380°C; the growth region temperature is 170°C to 210°C, preferably 180°C to 200°C.

[0019] In addition, in steps S3 and S4, the physical vapor deposition is carried out in an inert atmosphere, and the inert atmosphere can be nitrogen, helium and other inert atmospheres.

[0020] Specifically, in step S3, the first mask can be covered on the surface of the substrate and placed in the growth zone of the tube furnace, and the metal phthalocyanine can be placed in the source zone of the tube furnace. Then, an inert gas can be filled into the tube furnace at a flow rate of 50 - 300 sccm (preferably 100 - 200 sccm), and the pressure inside the tube can be controlled at 10 - 40 mbar (preferably 5 - 25 mbar). Furthermore, growth can be carried out for 100 - 150 min (preferably 110 - 130 min) under the above temperature control conditions. Subsequently, after cooling to room temperature in an inert atmosphere with the tube furnace, the substrate together with the first mask is taken out, the first mask is removed, and a one-dimensional metal phthalocyanine nanowire array with precise positioning and orientation growth is prepared on the substrate. In step S4, the second mask is covered on the substrate, and according to the structure of the target organic heterojunction, the second through-hole array on the second mask is arranged corresponding to the metal phthalocyanine nanowire array on the substrate. Then, the substrate together with the second mask is placed in the growth zone of the tube furnace, and tris(8-hydroxyquinoline)aluminum is sent to the source zone of the tube furnace instead of the metal phthalocyanine. Then, an inert gas can be filled into the tube furnace at a flow rate of 50 - 300 sccm (preferably 100 - 200 sccm), and the pressure inside the tube can be controlled at 10 - 40 mbar (preferably 5 - 25 mbar). Furthermore, growth can be carried out for 10 - 60 min (preferably 20 - 50 min) under the above temperature control conditions. Subsequently, after cooling to room temperature in an inert atmosphere with the tube furnace, the substrate together with the second mask is taken out, the second mask is removed, and an organic heterojunction nanowire array with precise positioning and orientation growth is prepared on the substrate.

[0021] In step S3, the temperature of the source zone can also be raised to a predetermined temperature first, and then the metal phthalocyanine is sent to the source zone. Similarly, in step S4, the temperature of the source zone can be raised to a predetermined temperature first, and then tris(8-hydroxyquinoline)aluminum is sent to the source zone.

[0022] The metal phthalocyanine specifically uses metal phthalocyanine powder. In some embodiments of the present invention, in step S3, the metal phthalocyanine is selected from at least one of copper phthalocyanine, zinc phthalocyanine, cobalt phthalocyanine, ferrous phthalocyanine, and nickel phthalocyanine. Copper phthalocyanine is preferably used.

[0023] Through research, CuPc and Alq3 can form a nanowire heterojunction based on the following reasons:

[0024] (1) CuPc and Alq3 have similar molecular structures

[0025] Among them, the molecular formula of copper phthalocyanine (CuPc) is C 32 H 16 CuN8, which is a P-type organic semiconductor material. Specifically, it is a compound with an 18-electron large conjugated system composed of four isoindole units. There is a diameter of about 2.70×10 -10The cavity of m, copper element can chelate with phthalocyanine through two covalent bonds and two coordination bonds at the cavity position to form highly stable copper phthalocyanine; tris(8-hydroxyquinoline)aluminum (Alq3), molecular formula C 27 H 18 AlN3O3, which is an N-type organic semiconductor material. Specifically, it is an octahedral complex formed by metal aluminum ions (Al 3+ ) and three 8-hydroxyquinoline (HQ) molecules. Among them, 8-hydroxyquinoline is a conjugated polyaryl heterocyclic compound with a fused ring structure and has strong coordination ability.

[0026] (2) CuPc and Alq3 have similar lattice constants

[0027] CuPc, α = 90.00°, β = 120.93°, γ = 90.00°;

[0028] Alq3, α-Alq3: α = 69.890°, β = 89.464°, γ = 82.520°.

[0029] (3) CuPc nanowires are π-π stacked along the

[010] direction, and Alq3 nanowires are π-π stacked along the

[010] direction.

[0030] (4) The energy band structure of the CuPc-Alq3 heterojunction is matched. It belongs to a type-I heterojunction. The energy band structure of a type-I heterojunction is nested and aligned. The conduction band bottom and valence band top of the narrow-band material are both located in the bandgap of the wide-band material.

[0031] In some embodiments of the present invention, in step S2, the hydrophobic treatment uses an octadecyltrichlorosilane (OTS) solution as the hydrophobic agent. The octadecyltrichlorosilane (OTS) solution can be specifically prepared by mixing OTS with an organic solvent. The organic solvent can be n-hexane or other organic solvents. The mass ratio of OTS to the organic solvent can be controlled at 1:800 - 1200. The hydrophobic treatment can be carried out in a closed container to prevent the reaction of moisture in the air with the OTS solution.

[0032] In some embodiments of the present invention, in step S2, after the hydrophobic treatment, the sapphire substrate is cleaned and dried. Specifically, it can be rinsed with ethanol or distilled water solution, and then blown dry with a nitrogen gun.

[0033] In the second aspect of the present invention, an organic heterojunction nanowire array is proposed, which is prepared by the preparation method of any one of the above organic heterojunction nanowire arrays.

[0034] In a third aspect of the present invention, an optoelectronic device is proposed, which includes any one of the above organic heterojunction nanowire arrays. The optoelectronic device can be a field effect transistor, a solar cell, a photodetector, a sensor, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below in conjunction with the drawings and embodiments, where:

[0036] Figure 1 is the preparation flow chart of the organic heterojunction nanowire array in Example 1;

[0037] Figure 2 is the positioning design drawing of the preparation process of the organic heterojunction nanowire array in Example 1;

[0038] Figure 3 is the scanning electron microscope microstructural diagram of the sapphire substrate with a nanoscale channel array prepared in Example 1;

[0039] Figure 4 is the structure test diagram of the channel array on the sapphire substrate with a nanoscale channel array prepared in Example 1;

[0040] Figure 5 is the X-ray diffraction pattern of a metal phthalocyanine nanowire unit in the copper phthalocyanine nanowire array prepared on the sapphire substrate surface in Example 1;

[0041] Figure 6 is the optical microscope picture of a copper phthalocyanine copper nanowire unit in the copper phthalocyanine nanowire array prepared on the sapphire substrate in Example 1 and the organic heterojunction nanowire unit further prepared on this basis;

[0042] Figure 7 are the optical microscope pictures at different magnifications of the organic heterojunction nanowire array prepared in Example 1 under 365 nm laser irradiation;

[0043] Figure 8 is the scanning electron microscope microstructural diagram of an organic heterojunction nanowire unit in the organic heterojunction nanowire array prepared in Example 1;

[0044] Figure 9 is the scanning electron microscope microstructural diagram of one of the CuPc-Alq3 heterojunction nanowires prepared on the M-plane sapphire in Example 1;

[0045] Figure 10 are the optical microscope pictures of the organic heterojunction nanowires prepared in Comparative Example 1 and their optical microscope pictures under 365 nm laser irradiation;

[0046] Figure 11Optical microscope images of the organic heterojunction nanowires prepared in Comparative Example 2 and under 365 nm laser irradiation. Detailed implementation mode

[0047] The following will clearly and completely describe the concept and technical effects of the present invention in combination with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0048] Example 1

[0049] In this example, an organic heterojunction nanowire array was prepared. The preparation steps are as follows Figure 1 , specifically including:

[0050] S1. Take the M-plane sapphire wafer shown in (a) in Figure 1 , put it into a high-temperature box furnace at 1600 °C, keep it at a constant temperature for 10 h, and then take it out after cooling to room temperature with the furnace. The surface of the obtained sapphire wafer has a V-shaped nanoscale horizontal channel array with a spacing of 50-150 nm and a depth of about 10-30 nm along the direction, as shown in (b) in Figure 1 ; Cut the obtained sapphire wafer into 1.0×1.0 cm 2 size, ultrasonically clean it with ethanol, acetone, ethanol, deionized water, and ethanol solution for 10 min in sequence, and dry it with a nitrogen gun to obtain a sapphire substrate.

[0051] S2. As shown in (c) in Figure 1 , place the sapphire substrate in a mixed solution composed of 10 μL of OTS and 10 mL of n-hexane for hydrophobic treatment for 2 h. During the hydrophobic treatment process, seal the beaker mouth to prevent moisture in the air from reacting with the OTS solution; after the hydrophobic treatment, take out the sapphire substrate, quickly rinse it with acetone, ethanol, and distilled water solution, and then dry it with a nitrogen gun.

[0052] S3. As shown in Figure 2 , take a fixing device 10 with a fixed groove, a first mask plate 20 with a first through-hole array, and a second mask plate 30 with a second through-hole array. Among them, the fixed groove includes a substrate fixing groove 11 and a mask plate fixing groove 12, and the substrate fixing groove 11 and the mask plate fixing groove 12 are arranged in sequence along the direction extending from the bottom to the top of the fixed groove; the first mask plate 20 is a mask plate for growing a copper phthalocyanine nanowire array, the second mask plate 30 is a mask plate for growing an aluminum tris(8-hydroxyquinoline) nanowire array, and the sizes of the first mask plate 20 and the second mask plate 30 are adapted to the mask plate fixing groove.

[0053] Dissolve 5 g of polyvinyl alcohol particles (PVA) in 9 mL of water to prepare a PVA aqueous solution with a mass fraction of 5%; use a pipette to aspirate 10 μL of the PVA solution and drop it into the substrate fixing groove 11 of the fixing device, and then place the sapphire substrate 40 into the substrate fixing groove 11; then place the fixing device 10 together with the sapphire substrate 40 on a heating table at 100 °C and heat for 1 min until the sapphire substrate 40 is firmly adhered to the substrate fixing groove 11 of the fixing device 10; then place the first mask plate 20 into the mask plate fixing groove 12 of the fixing device 10, and the first mask plate 20 is accurately fixed to the mask plate fixing groove 12, as shown in Figure 2 (b) in

[0054] S4. Weigh 10 mg of copper phthalocyanine powder and place it in the sample pushing rod. Put the copper phthalocyanine powder and the fixing device 10 with the sapphire substrate 40 and the first mask plate 20 obtained in step S3 into the quartz tube of the tube furnace at the same time. The distance between the copper phthalocyanine powder and the sapphire substrate 40 is 17 cm. Ensure that the copper phthalocyanine powder is located in the source area, and the fixing device 10 with the sapphire substrate 40 and the first mask plate 20 is located in the growth area, and mark the position; pull out the sample pushing rod with the phthalocyanine powder from the source area and mark it again to facilitate the sample pushing rod to reach the same position in the source area when it is pushed in again.

[0055] S5. Adjust the nitrogen gas flow rate in the quartz tube to 50 sccm, control the tube pressure at 10 mbar. When the temperature in the source area of the tube furnace is heated to 450 °C and the temperature in the growth area is heated to 240 °C, push the sample pushing rod to the marked position in the source area, and the copper phthalocyanine powder starts to evaporate. The growth time is 120 min; then cool down to room temperature with the tube furnace under a nitrogen atmosphere, and take out the fixing device 10 with the sapphire substrate 40 and the first mask plate 20. That is, a copper phthalocyanine metal nanowire array is prepared on the sapphire substrate 40, as shown in Figure 1 (d) and Figure 2 (c) in

[0056] S6. As shown in Figure 2As shown in Fig. (d), replace the first mask 20 on the fixing device 10 with the second mask 30. Weigh 10 mg of tris(8-hydroxyquinoline)aluminum powder into the sample pushing rod. Then, put the tris(8-hydroxyquinoline)aluminum powder and the fixing device 10 with the sapphire substrate 40 and the second mask 30 fixed obtained in step S3 into the quartz tube of the tube furnace at the same time. The distance between the tris(8-hydroxyquinoline)aluminum powder and the sapphire substrate 40 is 25 cm. Ensure that the tris(8-hydroxyquinoline)aluminum powder is located in the source area, and the fixing device 10 with the sapphire substrate 40 and the second mask 30 fixed is located in the growth area, and mark the positions well; pull out the sample pushing rod with the tris(8-hydroxyquinoline)aluminum powder from the source area and mark it again, so that when the sample pushing rod is pushed in again, it can reach the same position in the source area.

[0057] S7. Adjust the nitrogen gas flow rate in the quartz tube to 150 sccm, control the pressure inside the tube at 16 mbar. When the temperature of the source area of the tube furnace is heated to 360 °C and the temperature of the growth area is heated to 190 °C, push the sample pushing rod to the marked position in the source area, and the tris(8-hydroxyquinoline)aluminum powder starts to evaporate, and the growth time is 30 min.

[0058] S8. Cool down to room temperature in the furnace under a nitrogen atmosphere, take out the fixing device 10 with the sapphire substrate 40 and the second mask 30 fixed, remove the second mask 30, remove the sapphire substrate 40 in the fixing groove, and obtain an organic heterojunction nanowire array on the sapphire substrate, that is, a CuPc-Alq3 organic heterojunction nanowire array, as shown in Figure 1 Fig. (e) and Figure 2 Fig. (e). The CuPc-Alq3 organic heterojunction nanowire array includes a plurality of CuPc-Alq3 organic heterojunction nanowire units arranged in an array.

[0059] Comparative Example 1

[0060] This comparative example prepared an organic heterojunction nanowire. The specific preparation steps include:

[0061] S1. Put the M-plane sapphire wafer into a high-temperature box furnace at 1600 °C, keep it at a constant temperature for 10 h, and then take it out after cooling down to room temperature in the furnace. The surface of the obtained sapphire wafer has a V-shaped nanoscale horizontal channel array with a spacing of 50 - 150 nm along the direction; cut the obtained sapphire wafer into a size of 1.0 × 1.0 cm 2 , and ultrasonically clean it with ethanol, acetone, ethanol, deionized water, and ethanol solution for 10 min in sequence, and dry it with a nitrogen gun to obtain a sapphire substrate.

[0062] S2. Place the sapphire substrate in a mixed solution composed of 10 μL of OTS and 10 mL of n-hexane for hydrophobic treatment for 2 h. During the hydrophobic treatment, seal the beaker mouth to prevent moisture in the air from reacting with the OTS solution. After the hydrophobic treatment, take out the sapphire substrate, quickly rinse it with ethanol and distilled water solution, and then dry it with a nitrogen gun.

[0063] S3. Weigh 10 mg of copper phthalocyanine powder and place it in the sample pushing rod. Put the copper phthalocyanine powder and the sapphire substrate obtained in step S2 into the quartz tube of the tube furnace at the same time. The distance between the copper phthalocyanine powder and the sapphire substrate is 17 cm. Ensure that the copper phthalocyanine powder is located in the source area and the sapphire substrate is located in the growth area, and mark the positions. Pull out the sample pushing rod containing the phthalocyanine powder from the source area and mark it again so that when the sample pushing rod is pushed in again, it reaches the same position in the source area.

[0064] S5. Adjust the nitrogen gas flow rate in the quartz tube to 50 sccm, control the tube pressure at 10 mbar. When the temperature of the source area of the tube furnace is heated to 450 °C and the temperature of the growth area is heated to 240 °C, push the sample pushing rod to the marked position in the growth area. The copper phthalocyanine powder starts to evaporate, and the growth time is 120 min. Then, cool down to room temperature with the tube furnace under a nitrogen atmosphere, take out the sapphire substrate, and thus metal copper phthalocyanine nanowires are prepared on the sapphire substrate.

[0065] S6. Weigh 10 mg of tris(8-hydroxyquinoline)aluminum powder in the sample pushing rod. Put the tris(8-hydroxyquinoline)aluminum powder and the sapphire substrate with metal copper phthalocyanine nanowires grown on its surface into the quartz tube of the tube furnace at the same time. The distance between the tris(8-hydroxyquinoline)aluminum powder and the sapphire substrate is 25 cm. Ensure that the tris(8-hydroxyquinoline)aluminum powder is located in the source area and the sapphire substrate is located in the growth area, and mark the positions. Pull out the sample pushing rod containing the tris(8-hydroxyquinoline)aluminum powder from the source area and mark it again so that when the sample pushing rod is pushed in again, it reaches the same position in the source area.

[0066] S7. Adjust the nitrogen gas flow rate in the quartz tube to 150 sccm, control the tube pressure at 16 mbar. When the temperature of the source area of the tube furnace is heated to 360 °C and the temperature of the growth area is heated to 190 °C, push the sample pushing rod to the marked position in the source area. The tris(8-hydroxyquinoline)aluminum powder starts to evaporate, and the growth time is 30 min.

[0067] S8. Cool down to room temperature with the furnace under a nitrogen atmosphere, take out the sapphire substrate, and CuPc-Alq3 organic heteronanowires are prepared on the sapphire substrate.

[0068] Comparative Example 2

[0069] In this comparative example, an organic heterojunction nanowire was prepared. The difference between this comparative example and Comparative Example 1 is that the step S2 in Comparative Example 1 for hydrophobic treatment of the substrate surface was cancelled, and other operations are the same as those in Comparative Example 1.

[0070] Test Example

[0071] The sapphire substrate with a nanoscale channel array prepared by annealing treatment in Example 1 was observed and tested using a scanning electron microscope and an atomic force microscope respectively. The obtained results are as Figure 3 and Figure 4 shown. Figure 4 In (a) is the atomic force microscope micrograph of the channel array on the sapphire substrate with a nanoscale channel array, and (b) is the corresponding channel depth profile diagram. From Figure 3 and Figure 4 it can be seen that the channel array is a V-shaped nanoscale channel array with a width of 50 - 150 nm and a depth of 10 - 30 nm.

[0072] An X-ray diffractometer was used to detect a copper phthalocyanine nanowire unit in the metal phthalocyanine nanowire array prepared on the sapphire substrate in Example 1. The obtained XRD pattern is as Figure 5 shown. From Figure 5 it can be seen that the crystallinity of the CuPc nanowires grown on the surface of the sapphire substrate with a nanoscale channel array in Example 1 is high.

[0073] An optical microscope was used to observe a copper phthalocyanine nanowire unit in the metal phthalocyanine nanowire array prepared on the sapphire substrate in Example 1 and a CuPc-Alq3 organic heterojunction nanowire unit further prepared on this basis. The obtained results are respectively as Figure 6 shown, where (a) is the optical microscope picture of the copper phthalocyanine nanowire unit, and (b) is the optical microscope picture of the corresponding CuPc-Alq3 organic heterojunction nanowire unit. From Figure 6 it can be seen that the nanowire array grows well, and the alignment position of the heterojunction is precisely controllable.

[0074] An optical microscope was used to observe the organic heterojunction nanowire array prepared in Example 1 under 365 nm laser irradiation at different magnifications. The obtained results are as Figure 7 shown. From Figure 7 it can be seen that the heterojunction nanowire array is arranged neatly, and the alignment position of the heterojunction is precisely controllable.

[0075] A scanning electron microscope was used to observe an organic heterojunction nanowire unit in the organic heterojunction nanowire array prepared in Example 1. The obtained result is as Figure 8As shown. Moreover, a scanning electron microscope was used to observe one of the CuPc-Alq3 heterojunction nanowires prepared on M-plane sapphire in Example 1, and the results are as Figure 9 shown. From Figure 8 and Figure 9 , it can be seen that the CuPc and Alq3 nanowires are well lapped to form a good heterojunction structure.

[0076] As can be seen from the above, in Example 1, the M-plane sapphire was annealed, and a nanoscale channel array could be formed on its surface after annealing. Then, taking it as a substrate, a hydrophobic treatment was carried out on it. Subsequently, a metal phthalocyanine nanowire array was prepared on the surface of the hydrophobic-treated substrate with a nanoscale channel array by physical vapor deposition with the aid of a first mask template having a first through-hole array. Among them, the nanoscale channel array on the surface of the hydrophobic-treated substrate during the physical vapor deposition process can guide the directional and orderly growth of the metal phthalocyanine nanowires, and the preparation of the patterned metal phthalocyanine nanowire array can be realized through the first through-hole array on the first mask template; then, an aluminum tris(8-hydroxyquinoline) nanowire array connected to the metal phthalocyanine nanowire array was prepared on the surface of the hydrophobic-treated substrate with a nanoscale channel array by physical vapor deposition with the aid of a second mask template having a second through-hole array to form an organic heterojunction nanowire array. Among them, the growth region of the aluminum tris(8-hydroxyquinoline) nanowire array can be controlled through the second mask template and the second through-hole array thereon to realize the positioning and alignment of the organic heterojunction nanowires. The nanoscale channel array on the surface of the substrate during the physical vapor deposition process can guide the directional and orderly growth of the aluminum tris(8-hydroxyquinoline) nanowires on it.

[0077] In addition, an optical microscope was used to first observe the organic heterojunction nanowires prepared in Comparative Example 1, and then observe them under 365 nm laser irradiation. The results are as Figure 10 shown, where (a) is an optical microscope image of the organic heterojunction nanowires prepared in Comparative Example 1, and (b) is an optical microscope image of it under 365 nm laser irradiation. From Figure 10 , it can be seen that in Comparative Example 1, a metal phthalocyanine nanowire horizontal array and an Alq3 nanowire horizontal array were directly grown on the entire M-plane sapphire substrate, and no patterned nanowire integrated array was grown, so accurate heterojunction alignment could not be achieved, which was not conducive to the preparation of heterojunction nanowire devices and the in-situ integration of heteronanodevices.

[0078] An optical microscope was used to first observe the organic heterojunction nanowires prepared in Comparative Example 2, and then observe them under 365 nm laser irradiation. The results are as Figure 11 shown, where (a) is an optical microscope image of the organic heterojunction nanowires prepared in Comparative Example 2, and (b) is an optical microscope image of it under 365 nm laser irradiation. From Figure 11It can be seen that the heterojunction nanowires grown on the M-plane sapphire substrate that has only been annealed but not subjected to OTS treatment are not only short and disordered in length, but also cannot achieve heterojunction alignment and array controllability.

[0079] As described above, the preparation method of the organic heterojunction nanowire array of the present application can achieve the directional growth and alignment of the organic heterojunction nanowires, and further can achieve the in-situ large-scale construction and integration of the nanowire device array. The organic heterojunction nanowire array prepared by the preparation method of the present application can be used for the preparation of optoelectronic devices such as field effect transistors, solar cells, photodetectors, and sensors. Furthermore, the present application also provides an optoelectronic device, including any organic heterojunction nanowire array of the present application, and the optoelectronic device can be an optoelectronic device such as a field effect transistor, a solar cell, a photodetector, and a sensor.

[0080] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as a limitation on the scope of the invention patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for preparing an organic heterojunction nanowire array, characterized in that, It includes the following steps: S1. Prepare a nanoscale channel array on the surface of the substrate; S2. Perform a hydrophobic treatment on the surface; S3. With the aid of a first mask plate having a first through-hole array, prepare a metal phthalocyanine nanowire array on the surface by physical vapor deposition using metal phthalocyanine; S4. With the aid of a second mask plate having a second through-hole array, prepare an aluminum tris(8-hydroxyquinoline) nanowire array on the surface by physical vapor deposition, wherein the second through-hole array partially overlaps with the metal phthalocyanine nanowire array, and the second through-hole array is used to control the growth region of the aluminum tris(8-hydroxyquinoline) nanowire array, so that the aluminum tris(8-hydroxyquinoline) nanowire array overlaps with the metal phthalocyanine nanowire array to obtain an organic heterojunction nanowire array; The first mask plate and the second mask plate are respectively fixedly arranged on the surface of the substrate through a fixing device; the fixing device has a fixing groove, and the fixing groove includes a substrate fixing groove and a mask plate fixing groove which are sequentially arranged in the extending direction from the bottom to the top of the fixing groove; the size of the substrate is adapted to the size of the substrate fixing groove to be configured to clamp and fix the substrate through the substrate fixing groove; the sizes of the first mask plate and the second mask plate are both adapted to the size of the mask plate fixing groove to be configured to clamp and fix the first mask plate and the second mask plate through the mask plate fixing groove.

2. The preparation method of the organic heterojunction nanowire array according to claim 1, wherein In step S3 and step S4, the physical vapor deposition is carried out by vacuum evaporation.

3. The preparation method of the organic heterojunction nanowire array according to claim 1, wherein In step S3, the metal phthalocyanine is selected from at least one of copper phthalocyanine, zinc phthalocyanine, cobalt phthalocyanine, iron phthalocyanine, and nickel phthalocyanine.

4. The preparation method of the organic heterojunction nanowire array according to claim 1, wherein In step S1, the nanoscale channel array is a V-shaped nanoscale channel array with a width of 50-150 nm and a depth of 10-30 nm.

5. The preparation method of the organic heterojunction nanowire array according to claim 1, characterized in that, In step S2, the hydrophobic treatment uses octadecyltrichlorosilane solution as a hydrophobic agent.

6. The preparation method of the organic heterojunction nanowire array according to claim 5, wherein In step S2, after the hydrophobic treatment, the substrate is cleaned and dried.

7. An organic heterojunction nanowire array, characterized in that, It is obtained by the preparation method of the organic heterojunction nanowire array according to any one of claims 1 to 6.

8. An optoelectronic device, characterized in that, It includes the organic heterojunction nanowire array according to claim 7.

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