A Conductive Polymer / Stibnite Selenide Heterojunction and Its Preparation Method and Optoelectronic Application

Abstract

The invention provides a conductive polymer / antimony selenide heterojunction, a preparation method thereof and an optoelectronic application, belonging to the technical field of semiconductor nanomaterials. In the invention, a metal salt mixed with Sb2Se3 is used as a precursor, mica or a silicon wafer is used as a carrier, and ultrathin Sb2Se3 nanometer triangular flakes are prepared by chemical vapor deposition; then the ultrathin Sb2Se3 nanometer triangular flakes are transferred to a substrate by a PMMA-assisted transfer method; and finally a conductive polymer / antimony selenide heterojunction is prepared by a standard spin coating method. The conductive polymer / antimony selenide heterojunction can obtain a higher-quality heterojunction type photodetector by virtue of the adjustable band gap of the conductive polymer.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor nanomaterials, and in particular, relates to a conductive polymer / antimony selenide heterojunction, a preparation method thereof, and optoelectronic applications. Background Art

[0002] Since the emergence of low-dimensional nanomaterials, due to their unique physical and chemical properties, they have received extensive attention from scientific research personnel. Because low-dimensional nanomaterials have characteristics such as small size, large specific surface area, adjustable light absorption, long photoelectron lifetime, and high carrier mobility, they have great application prospects in the field of optoelectronic detection. Optoelectronic detectors made of low-dimensional nanomaterials have many excellent optoelectronic properties, such as high responsivity, ultra-high optoelectronic gain, fast response, sub-wavelength effect, low power consumption, etc. In addition, due to the small size of low-dimensional materials and their relatively good compatibility with current semiconductor microelectronics technology, optoelectronic detectors based on low-dimensional nanomaterials have further promoted the high integration and miniaturization of optoelectronic detectors, which is crucial for the development of future high-performance optoelectronic detector systems.

[0003] As a typical p-type binary semiconductor material, Sb2Se3 has a band gap of approximately 1.0 - 1.2 eV, which is similar to the band gap of silicon at 1.1 eV. Moreover, its absorption coefficient is 105 cm -1 , which can well make up for the deficiencies of silicon-based optoelectronic detectors in terms of absorption range and absorption rate. At the same time, the main elements Sb and Se that make up Sb2Se3 are very abundant in the earth's crust. Based on the above advantages, Sb2Se3 is widely used in related fields such as gas sensing, catalysis, electrochromism, etc. due to its excellent optical properties and low cost. Detectors based on the morphological structures of single Sb2Se3 nanoribbons and nanorods have been reported, but there are problems of relatively low responsivity and too small on / off ratio (~17). In order to further improve the performance and obtain higher responsivity and larger on / off ratio, it is urgent to target heterojunction optoelectronic detectors based on Sb2Se3.

[0004] The photovoltaic effects of Schottky barriers, pn junctions, and heterojunctions are effective ways to solve the above problems. Currently, there are many reports on inorganic / inorganic semiconductor heterojunction nanostructures such as Sb2Se3 nanoribbons / Si, II-type band-aligned hybrid nanorods of Sb2Se3 / AgSbSe2 heterojunction structures, Sb2Se3 thin films / VO2, etc. However, inorganic / inorganic heterojunction photodetectors have many requirements for hybrid materials and device processing technologies, resulting in high costs and complex processing, which limits their practical applications. Therefore, it is necessary to prepare high-quality and stable photodetectors by a simple and low-cost method to improve their performance. To solve the above problems, using organic semiconductors instead of inorganic semiconductors has become a simple and effective way. Among them, p-type conductive polymers (polyaniline PANI, polypyrrole PPy, and poly(3,4-ethylenedioxythiophene) / poly(3-hexylthiophene) PEDOT / P3HT) are favored by researchers. Polyaniline (PANI) has many advantages, such as high conductivity, good mechanical flexibility, low cost, and high theoretical specific capacity. Polypyrrole (PPy) has a π-bond polymer chain structure, good conductivity, and good antioxidant properties. Compared with other conductive polymers, it has higher conductivity, is easy to form films, and is non-toxic. Poly(3,4-ethylenedioxythiophene) / poly(3-hexylthiophene) (PEDOT / P3HT) has good environmental and thermal stability, is not easily decomposed, and can be dissolved in most organic solvents, and is an important fluorescent material. High-performance ultraviolet photodetectors based on PANI / TiO2 nanorods and heterojunction-based self-driven ultraviolet-visible photodetectors of conductive polymers / Se microtubes have demonstrated the feasibility of using organic / inorganic semiconductor heterojunctions to achieve high-performance and self-driven photodetectors. However, the combination of conductive polymers and Sb2Se3 has not been deeply studied yet. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a conductive polymer / antimony selenide heterojunction, a preparation method thereof, and optoelectronic applications.

[0006] A preparation method of a conductive polymer / antimony selenide heterojunction includes the following steps:

[0007] (1) Mix a metal salt and Sb2Se3 as a precursor, use mica as a carrier, and prepare Sb2Se3 nanoscale triangular flakes by chemical vapor deposition.

[0008] (2) Use a PMMA-assisted transfer method to transfer the Sb2Se3 nanoscale triangular flakes from mica to a substrate, and coat the surface layer of the Sb2Se3 nanoscale triangular flakes loaded on the substrate with a conductive polymer to obtain the conductive polymer / antimony selenide heterojunction.

[0009] In an embodiment of the present invention, in step (1), the mass ratio of the metal salt to Sb2Se3 is 1:(1 - 10).

[0010] In one embodiment of the present invention, in step (1), the metal salt is one or more of NaCl, Na2SO4, NaBr, NaI, KCl, KBr, or KI.

[0011] In one embodiment of the present invention, in step (1), the chemical vapor deposition method steps: under an inert atmosphere, place the precursor in a heating vessel, and place mica on the surface layer of the precursor, and heat to obtain the Sb2Se3 nanoscale triangular flakes.

[0012] In one embodiment of the present invention, the heating process: raise the temperature to the growth temperature of 600 - 800 °C within 20 - 30 minutes, and keep the temperature constant for 10 - 30 minutes.

[0013] In one embodiment of the present invention, the conditions of the inert atmosphere: use argon with a flow rate of 30 - 80 sccm as the carrier gas. After the heating process of the Sb2Se3 nanoscale triangular flakes is completed, cool down and turn off the argon.

[0014] In one embodiment of the present invention, in step (2), the steps of the PMMA-assisted transfer method are: coat PMMA on the ultrathin Sb2Se3 nanoscale triangular flakes on mica, bake at 100 - 150 °C for 10 - 15 minutes to obtain PMMA / Sb2Se3 / mica, immerse the PMMA / Sb2Se3 / mica in water for 2 - 3 h to obtain a PMMA / Sb2Se3 thin film, and transfer it to a substrate, then bake at 80 - 150 °C for 5 - 10 minutes, and place it in an organic solvent to remove PMMA to obtain Sb2Se3 nanoscale triangular flakes loaded on the substrate.

[0015] In one embodiment of the present invention, the organic solvent is acetone.

[0016] In one embodiment of the present invention, the coating method is spin coating, and the spin coating speed of PMMA is 2000 - 3000 rpm, and the duration is 1 - 5 minutes.

[0017] In one embodiment of the present invention, in step (2), the conductive polymer is polyaniline, polypyrrole, or polythiophene.

[0018] The present invention also provides a conductive polymer / antimony selenide heterojunction obtained by the preparation method described above.

[0019] The present invention also provides an application of the conductive polymer / Sb2Se3 heterojunction in a photodetector.

[0020] The above technical solutions of the present invention have the following advantages compared with the prior art:

[0021] Most of the compositions of the Sb2Se3 heterojunctions described in the present invention are inorganic / inorganic types. Such a structure has many requirements in terms of material mixing and device processing, resulting in problems such as high production costs and complex processing difficulties, severely restricting the application of Sb2Se3 heterojunctions in the optoelectronic field. The present invention synthesizes Sb2Se3 nanoscale triangular flakes and combines them with a conductive polymer to form an inorganic / organic heterojunction. The preparation process is relatively simple and the cost is relatively low. The conductive polymer is well utilized to achieve the preparation of a heterojunction with a high built-in electric field, thereby obtaining a high-performance conductive polymer / Sb2Se3 nanoscale triangular flake heterojunction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in combination with the accompanying drawings, wherein

[0023] Figure 1 is an optical microscope picture of the Sb2Se3 nanoscale triangular flakes prepared in Example 1 of the present invention.

[0024] Figure 2 is the I-t curve of the polyaniline / Sb2Se3 nanoscale triangular flake heterojunction prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following further illustrates the present invention in combination with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the examples given are not intended to limit the present invention.

[0026] Optoelectronic performance test method: Ti / Au is coated on the mask plate of the polyaniline / Sb2Se3 nanoscale triangular flake heterojunction by magnetron sputtering as the upper electrode. The interdigital fingers of the mask plate are 10 mm long and 390 mm wide, and the distance between the two Ti / Au electrodes is about 2 mm. The current-voltage (I-V) and current-time (I-t) characteristics of the device are tested by the two-probe method.

[0027] Example 1: Preparation of PANI / Sb2Se3 nanoscale triangular flake heterojunction

[0028] High-quality ultrathin Sb2Se3 nanosheets are grown by chemical vapor deposition. The specific growth conditions are as follows: NaCl and Sb2Se3 are mixed as precursors in a mass ratio of 1:2, ground thoroughly in a quartz boat, and placed in the central region of a single-zone tube furnace. The furnace temperature in the central region of the single-zone tube furnace is raised to the growth temperature of 700 °C within 20 minutes and maintained at 700 °C for 10 minutes to grow ultrathin Sb2Se3 nanosheets. During the entire heating and crystal growth process, argon gas with a flow rate of 30 sccm is introduced as the carrier gas. After the growth process is completed, the furnace temperature is cooled to below 100 °C, and the argon gas is turned off. PMMA is spin-coated on the ultrathin Sb2Se3 nanosheets on fluorophlogopite and baked at 150 °C for 15 minutes. The spin-coating speed of PMMA is 2000 rpm, and the duration is 5 minutes. Then, the PMMA / Sb2Se3 / mica is immersed in deionized water for 3 h, and then the separated PMMA / Sb2Se3 film is transferred to a SiO2 / Si wafer and baked at 120 °C for 10 minutes. Then, acetone is used to remove PMMA, so as to obtain ultrathin Sb2Se3 nanosheets on the SiO2 / Si substrate, as Figure 1 shown.

[0029] The PANI / Sb2Se3 nanosheet heterojunction is prepared by the standard spin-coating method. The specific preparation process is as follows: PANI is spin-coated on the Sb2Se3 nanosheets on the SiO2 / Si substrate to form a PANI / Sb2Se3 nanosheet heterojunction. PANI uniformly covers the Sb2Se3 nanosheets to form a bilayer structure. A heterojunction device is fabricated. It can be seen from Figure 2 that when the laser with a wavelength of 940 nm irradiates and the voltage is 0 V, the photocurrent reaches 18.5 nA, the rise time is 15 ms, and the recovery time is 30 ms.

[0030] Example 2: Preparation of PPy / Sb2Se3 nanosheet heterojunction

[0031] High-quality ultrathin Sb2Se3 nanoplates are grown by chemical vapor deposition. The specific growth conditions are as follows: NaCl and Sb2Se3 are mixed as precursors in a mass ratio of 1:2, ground thoroughly in a quartz boat, and placed in the central region of a single-temperature-zone tube furnace. The furnace temperature in the central region of the single-temperature-zone tube furnace is raised to the growth temperature of 700 °C within 20 minutes and maintained at 700 °C for 10 minutes to grow ultrathin Sb2Se3 nanoplates. During the entire heating and crystal growth process, argon gas with a flow rate of 30 sccm is introduced as the carrier gas. After the growth process is completed, the furnace temperature is cooled to below 100 °C, and the argon gas is turned off. The ultrathin Sb2Se3 nanoplates on fluorophlogopite are spin-coated with PMMA and baked at 150 °C for 15 minutes. The spin-coating speed of PMMA is 2000 rpm, and the duration is 5 minutes. Then the PMMA / Sb2Se3 / mica is immersed in deionized water for 3 h, and then the separated PMMA / Sb2Se3 film is transferred to a SiO2 / Si wafer, then baked at 120 °C for 10 minutes, and then PMMA is removed using acetone to obtain ultrathin Sb2Se3 nanoplates on the SiO2 / Si substrate.

[0032] The PPy / Sb2Se3 nanoplate heterojunction is prepared by the standard spin-coating method. The specific preparation process is as follows: PPy is spin-coated on the Sb2Se3 nanoplates on a Si / SiO2 substrate to form a PPy / Sb2Se3 nanoplate heterojunction. PPy uniformly covers the Sb2Se3 nanoplates to form a bilayer structure. A heterojunction device is fabricated. When irradiated with a laser with a wavelength of 940 nm, the photocurrent reaches 10 nA at a voltage of 0 V, the rise time is 31 ms, and the recovery time is 50 ms.

[0033] Example 3: Preparation of PEDOT / Sb2Se3 heterojunction nanorods

[0034] High-quality ultrathin Sb2Se3 nanoplates are grown by chemical vapor deposition. The specific growth conditions are as follows: NaCl and Sb2Se3 are mixed as a precursor in a mass ratio of 1:2, ground thoroughly in a quartz boat, and placed in the central region of a single-zone tube furnace. The furnace temperature in the central region of the single-zone tube furnace is raised to the growth temperature of 700 °C within 20 minutes and maintained at 700 °C for 10 minutes to grow ultrathin Sb2Se3 nanoplates. During the entire heating and crystal growth process, argon gas with a flow rate of 30 sccm is introduced as the carrier gas. After the growth process is completed, the furnace temperature is cooled to below 100 °C, and the argon gas is turned off. PMMA is spin-coated on the ultrathin Sb2Se3 nanoplates on fluorophlogopite and baked at 150 °C for 15 minutes. The spin-coating speed of PMMA is 2000 rpm, and the duration is 5 minutes. Then the PMMA / Sb2Se3 / mica is immersed in deionized water for 3 h, and then the separated PMMA / Sb2Se3 film is transferred to a SiO2 / Si wafer, then baked at 120 °C for 10 minutes, and then PMMA is removed using acetone to obtain ultrathin Sb2Se3 nanoplates on the SiO2 / Si substrate.

[0035] The PEDOT / Sb2Se3 nanoplate heterojunction is prepared by the standard spin-coating method. The specific preparation process is as follows: PEDOT is spin-coated on the Sb2Se3 nanoplates on a Si / SiO2 substrate to form a PEDOT / Sb2Se3 nanoplate heterojunction. As Figure 2 shown, PEDOT uniformly covers the Sb2Se3 nanoplates, forming a bilayer structure. A heterojunction device is fabricated. When irradiated with a laser with a wavelength of 940 nm, the photocurrent reaches 5 nA at a voltage of 0 V, with a rise time of 25 ms and a recovery time of 43 ms.

[0036] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of this invention.

Claims

1. A preparation method of a conductive polymer / antimony selenide heterojunction, characterized in that, It includes the following steps: (1) Mix a metal salt with Sb2Se3 as a precursor, and prepare Sb2Se3 nanoscale triangular flakes by chemical vapor deposition; (2) Transfer the Sb2Se3 nanoscale triangular flakes to a substrate by PMMA-assisted transfer method, and coat a conductive polymer on the surface layer of the Sb2Se3 nanoscale triangular flakes loaded on the substrate to obtain the conductive polymer / antimony selenide heterojunction; The conductive polymer is polyaniline, polypyrrole or polythiophene.

2. The preparation method according to claim 1, wherein, In step (1), the mass ratio of the metal salt to Sb2Se3 is 1:1 - 10.

3. The preparation method according to claim 1, characterized in that, In step (1), the metal salt is one or more of NaCl, Na2SO4, NaBr, NaI, KCl, KBr or KI.

4. The preparation method according to claim 1, wherein In step (1), the steps of chemical vapor deposition method: under an inert atmosphere, place the precursor in a heating vessel, and place a carrier on the surface layer of the precursor, and heat to obtain the Sb2Se3 nanoscale triangular flakes.

5. The preparation method according to claim 4, characterized in that, The heating process: rise to the growth temperature of 600 - 800 °C within 20 - 30 minutes, and keep the temperature constant for 10 - 30 minutes.

6. The preparation method according to claim 1, wherein In step (2), the steps of the PMMA-assisted transfer method are: coat PMMA on the ultrathin Sb2Se3 nanoscale triangular flakes on the carrier, bake at 100 - 150 °C for 10 - 15 minutes to obtain PMMA / Sb2Se3 / carrier, immerse the PMMA / Sb2Se3 / carrier in water for 2 - 3 h to obtain a PMMA / Sb2Se3 thin film, transfer it to a substrate, bake at 80 - 150 °C for 5 - 10 minutes, and immerse it in an organic solvent to obtain the Sb2Se3 nanoscale triangular flakes loaded on the substrate.

7. The preparation method according to claim 6, characterized in that, The coating method is spin coating, and the spin coating speed of PMMA is 2000 - 3000 rpm, and the duration is 1 - 5 minutes.

8. The conductive polymer / antimony selenide heterojunction obtained by the preparation method according to any one of claims 1 - 7.

9. The application of the conductive polymer / antimony selenide heterojunction according to claim 8 in a photodetector.

Images