A fibrous lead-free double perovskite photodetector and a preparation method thereof

Abstract

The application provides a fibrous lead-free double perovskite photodetector and a preparation method thereof. 2 B + M 3+ The main fiber of a lead-free double perovskite thin film layer of X6 is twisted and wound together with another conductive fiber to form the photodetector, wherein A is one or more of K, Rb and Cs; B + is Li + , Na + , K + , Rb + , Cs + , Ag + ; M 3+ is one or more of Al 3+ , Ga 3+ , In 3+ , Sb 3+ , Bi 3+ , Sc 3+ , Y 3+ ; X is one or more of Cl, Br and I; the nanometer TiO2 array is obtained by growing a seed-assisted hydrothermal method on a core electrode, then a lead-free double perovskite thin film is deposited on the nanometer TiO2 array by using an electrophoretic deposition method, and finally the lead-free double perovskite thin film is twisted and wound together with a conductive fiber to form a fibrous photodetector, the structure photodetector has the advantages of good flexibility, lead-free toxicity, good environmental stability and weavability, and has a great application prospect in the field of wearable visual textiles.

Description

Technical Field

[0001] This invention relates to the field of photodetectors, and more particularly to the device structure and fabrication method of a fibrous lead-free double perovskite photodetector. Background Technology

[0002] Photodetectors, which capture optical signals and convert them into electrical signals, are cornerstone components for numerous applications, including optical communication, biomedical imaging, nondestructive testing, and machine vision. For example, the first flexible perovskite photodetector was introduced in [Advanced Functional Materials 24.46(2014):7373-7380], which was assembled by depositing MAPbI3 on ​​a flexible ITO substrate. This device exhibited a wide optical response range from ultraviolet (UV) to the entire visible light spectrum.

[0003] In the literature [Nanoscale 11.6(2019):2871-2877], Li et al. developed an improved solution method to prepare high-quality CsPbBr3 thin films on PET substrates with interdigitated gold electrodes, and the prepared photodetectors exhibited high response speeds. In the literature [Advanced Optical Materials 6.22(2018):1800679], Tang et al. designed flexible polarization photodetectors using CsPbI3 nanowire arrays with anisotropic orthogonal crystal structures as active materials. The fabricated flexible devices exhibited anisotropic photocurrent characteristics, and the anisotropy of the photocurrent changed very little after 500 bending cycles. In the literature [Advanced Materials 31.3(2019):1805913], Pan et al. based their work on CH3NH3PbI... 3- x Cl x Perovskite arrays have been used to develop large-area flat panel displays, and the fabricated flexible photodetector arrays can operate at low optical power (0.033 mW / cm²). -2 It exhibits excellent photoelectric performance and a wide spectral response range, and the photocurrent of the device does not change significantly after being bent hundreds of times at different bending angles.

[0004] The aforementioned flexible devices are all planar photodetectors assembled from lead-based perovskite, thus making it difficult to avoid problems such as lead toxicity and poor environmental stability. Lead-free double perovskite A2B + M 3+ The crystal structure of X6 originates from the ABX3 type structure, in which two B... 2+ B + and M 3+ Replacement, lead-free double perovskite A2B + M 3+X6 crystals possess advantages such as long carrier lifetime and good environmental stability. To date, there are few reports on flexible lead-free double perovskite devices; existing reports are all planar structures based on sheet substrates, and photodetectors with fibrous lead-free double perovskite structures have not yet been reported.

[0005] Electrophoretic deposition assembles nanoparticles by controlling an electric field, similar to electrostatic assembly which uses electrostatic interactions to fix nanoparticles onto a substrate. This process uses a conductive substrate as an electrode, generating a varying electric field by changing the voltage and controlling the deposition time to regulate film thickness and quality. Compared to traditional film deposition methods, this method produces high-quality films with controllable thickness and is not limited by the shape of the substrate material. Summary of the Invention

[0006] To address the aforementioned issues, this invention proposes a fibrous lead-free double perovskite photodetector and its fabrication method. The device structure comprises a fibrous core electrode, a TiO2 nanorod array, a lead-free double perovskite thin film layer, and a conductive fiber. The realization of this device mainly consists of three parts: the TiO2 nanorod array is grown on the fibrous core electrode using a seed-assisted hydrothermal method; then, a lead-free double perovskite thin film is deposited on the TiO2 nanorod array using an electrophoretic deposition method; and finally, the film is twisted and wound together with a conductive fiber to form a fibrous photodetector.

[0007] The specific steps are as follows:

[0008] Step 1: Grow TiO2 nanorod arrays on fibrous core electrodes, with TiO2 nanorod lengths ranging from 50 to 500 nm; Step 2: Dissolve AX and B using a polar solvent. + X, M 3+ X3 and organic amine ligands were used to obtain precursor solutions with a precursor concentration of 0.1–10 mol / L;

[0009] Step 3: Inject the precursor solution into a nonpolar solvent to obtain lead-free double perovskite sol;

[0010] Step 4: Deposit a lead-free double perovskite film layer with a thickness of 100 nm to 2 μm on a TiO2 nanorod array using electrophoretic deposition in a lead-free double perovskite sol to obtain the main fibers;

[0011] Step 5: Twist and wind the main fiber obtained in Step 4 and another carbon nanotube fiber to assemble a fibrous photodetector.

[0012] Where: A is one of K, Rb, and Cs; B + For Li + Na + K + 、Rb + Cs+ Ag + One of them; M 3+ For Al 3+ Ga 3 + In 3+ Sb 3+ Bi 3+ ,Sc 3+ Y 3+ One or more of the following; X is one or more of Cl, Br, and I.

[0013] The fibrous core electrode used is one of silver fiber, carbon fiber, copper fiber and carbon nanotube fiber, with a diameter of ≤0.2mm. If it exceeds 0.2mm, the flexibility is insufficient.

[0014] The specific steps for growing TiO2 nanorod arrays on the core electrode are divided into two steps: (1) The core electrode is pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Then, the core electrode with TiO2 nanoparticle seeds is transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 6 h to prepare core electrode fibers coated with TiO2 nanorod arrays.

[0015] The TiO2 nanorods have a length of 50–500 nm. When the length of the TiO2 nanorods is less than 50 nm, the contact between the perovskite layer and the TiO2 nanorod array is not tight enough, thus reducing the photocurrent of the device. When the length of the TiO2 nanorods exceeds 500 nm, the TiO2 nanorods will directly penetrate the perovskite layer, thereby increasing the dark current of the device.

[0016] The polar solvent is one or more of N,N-dimethylformamide and dimethyl sulfoxide, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 1:1 to 1:20. The addition of dimethyl sulfoxide can improve the quality of the deposited film, but adding too much will reduce the stability of the sol.

[0017] The organic amine ligands are primary amines with 15 or fewer carbon atoms, which can form strong coordination with perovskite, thereby forming high-quality nanocrystals and maintaining the stability of the sol.

[0018] The precursor concentration is 0.1–10 mol / L. When the precursor concentration exceeds 10 mol / L, the precursor cannot dissolve completely; when it is below 0.1 mol / L, the precursor content is too low, resulting in uneven film deposition by subsequent electrophoresis. In step three, the non-polar solvent used to prepare the sol is one of toluene, chloroform, or n-hexane. The difference in solubility of perovskite between the non-polar solvent and the polar solvent in the precursor induces a crystallization reaction in the perovskite. In step four, the electrophoretic deposition of the perovskite film uses a deposition voltage of 50–200 V, a deposition time of 1–200 min, and a distance of 1 cm between electrodes. When the deposition voltage is less than 50 V, the generated electric field is too small to allow nanocrystals to deposit on the core electrode; when the deposition voltage is greater than 200 V, the electric field is too large, causing the nanocrystals to move too quickly, resulting in uneven film deposition.

[0019] In step four, the lead-free double perovskite film deposited by electrophoresis has a thickness of 100 nm to 2 μm. When the film thickness is within this range, the carrier mobility is the highest, and the prepared photodetector has a faster response speed.

[0020] The growth of TiO2 nanorod array in step one and the preparation of lead-free double perovskite sol in steps three and four are parallel processes, and changing the order does not affect the preparation of the photodetector.

[0021] The present invention has the following advantages: (1) Lead-free double perovskite sol is synthesized by antisolvent method, the synthesis steps are simple, the obtained sol has good stability and no lead toxicity; (2) Lead-free double perovskite thin film is deposited by electrophoretic deposition method, the film prepared by this method is uniform and dense, and is not limited by the shape of the substrate material; (3) Photodetector is prepared by fiber substrate material, the obtained device has good flexibility and is woven, and has great application prospects in the field of wearable visual textiles. Attached Figure Description

[0022] Figure 1 : Schematic diagram of the device structure and cross-sectional diagram of the core electrode.

[0023] Figure 2 Scanning electron microscope image of the TiO2 nanorod array in Example 1.

[0024] Figure 3 Example 1: Scanning electron microscope image of a core electrode with a lead-free double perovskite film deposited on it.

[0025] Figure 4 The device in Example 1 operates at a power of 6mW / cm². 2 The photocurrent over time varies with the external light source under cyclical on / off conditions of a 365nm laser.

[0026] Figure 5Example 1: The photocurrent of the device changes with the number of bends at the same bending angle. Example

[0027] Example 1

[0028] Step 1: A silver fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Next, the silver fiber with TiO2 nanoparticle seeds was transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 6 h to prepare flexible silver fibers coated with a TiO2 nanorod array.

[0029] Step 2: Add 0.0851g CsBr, 0.0376g AgBr, 0.0723g SbBr3 and 0.4ml benzylamine to a mixed solvent of 5ml DMF and 5ml DMSO and stir for 1 hour until completely dissolved to form a translucent precursor solution; Step 3: Take 100ul of the precursor solution and quickly inject it into 10ml of toluene antisol and shake vigorously for 30s to obtain a light yellow translucent sol;

[0030] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm parallel to the negative terminal and insert it into the sol. Apply a voltage of 150V, perform electrophoretic deposition for 20 minutes, and then place it in an 85℃ drying oven for 15 minutes to obtain the main fiber.

[0031] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

[0032] Example 2

[0033] A carbon fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. The silver fiber with TiO2 nanoparticle seeds was then transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 3 h to prepare a flexible carbon fiber coated with a TiO2 nanorod array.

[0034] Step 2: Add 0.1702g CsBr, 0.0751g AgBr, 0.0723g SbBr3, 0.0897g BiBr3 and 0.4ml phenylethylamine to 5ml DMF and 5ml DMSO in sequence and stir for 1 hour until completely dissolved to form a translucent precursor solution;

[0035] Step 3: Take 200ul of the precursor solution and quickly inject it into 10ml of chloroform antisolvent and shake vigorously for 30s to obtain a light yellow, translucent sol;

[0036] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm parallel to the negative terminal and insert it into the sol. Apply a voltage of 150V, perform electrophoretic deposition for 20 minutes, and then place it in an 85℃ drying oven for 15 minutes to obtain the main fiber.

[0037] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

[0038] Example 3

[0039] Step 1: A copper fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Next, the silver fiber with TiO2 nanoparticle seeds was transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 3 h to prepare a flexible copper fiber coated with a TiO2 nanorod array.

[0040] Step 2: Add 0.0857g CsBr, 0.0725g AgBr3, 0.0456g SbCl and 0.4ml phenylethylamine to 1ml DMF and 9ml DMSO in sequence and stir for 1 hour until completely dissolved to form a semi-transparent precursor solution;

[0041] Step 3: Take 100ul of the precursor solution and quickly inject it into 10ml of n-hexane antisolvent and shake vigorously for 30s to obtain a light yellow, translucent sol;

[0042] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm parallel to the negative terminal and insert it into the sol. Apply a voltage of 150V, perform electrophoretic deposition for 20 minutes, and then place it in an 85℃ drying oven for 15 minutes to obtain the main fiber.

[0043] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

[0044] Example 4

[0045] Step 1: A carbon nanotube fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Next, the silver fiber with TiO2 nanoparticle seeds was transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 6 h to prepare flexible carbon nanotube fibers coated with a TiO2 nanorod array.

[0046] Step 2: Add 0.0673g CsCl, 0.0287g AgCl, 0.0456g SbCl and 0.4ml phenylethylamine to a mixed solvent of 1ml DMF and 9ml DMSO and stir for 1 hour until completely dissolved to form a translucent precursor solution;

[0047] Step 3: Take 100ul of the precursor solution and quickly inject it into 10ml of n-hexane antisolvent and shake vigorously for 30s to obtain a light yellow, translucent sol;

[0048] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm parallel to the negative terminal and insert it into the sol. Apply a voltage of 100V, perform electrophoretic deposition for 10 min, and then place it in an 85℃ drying oven for 15 min to obtain the main fiber.

[0049] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

[0050] Example 5

[0051] Step 1: A copper fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Next, the silver fiber with TiO2 nanoparticle seeds was transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 3 h to prepare a flexible copper fiber coated with a TiO2 nanorod array.

[0052] Step 2: Add 0.0851g CsBr, 0.0376g AgBr, 0.0723g SbBr3 and 0.4ml phenylethylamine to a mixed solvent of 4ml DMF and 6ml DMSO and stir for 1 hour until completely dissolved to form a semi-transparent precursor solution;

[0053] Step 3: Take 100ul of the precursor solution and quickly inject it into 10ml of n-hexane antisolvent and shake vigorously for 30s to obtain a light yellow, translucent sol;

[0054] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm parallel to the negative terminal and insert it into the sol. Apply a voltage of 200V, perform electrophoretic deposition for 10 min, and then place it in an 85℃ drying oven for 15 min to obtain the main fiber.

[0055] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

[0056] Example 6

[0057] Step 1: A copper fiber was pretreated with O2 plasma for 5 min, and then immersed in an aqueous solution of TiCl4 for 1 h to grow TiO2 nanoparticle seeds. Next, the silver fiber with TiO2 nanoparticle seeds was transferred to a polytetrafluoroethylene-lined hydrothermal reactor containing a hydrochloric acid / deionized water solution of TiCl4 and reacted for 6 h to prepare a flexible copper fiber coated with a TiO2 nanorod array.

[0058] Step 2: Add 0.0851g CsBr, 0.0376g AgBr, 0.0723g SbBr3 and 0.1ml benzylamine to a mixed solvent of 0.5ml DMF and 9.5ml DMSO and stir for 1 hour until completely dissolved to form a translucent precursor solution;

[0059] Step 3: Take 100ul of the precursor solution and quickly inject it into 10ml of toluene antisolvent and shake vigorously for 30s to obtain a light yellow, translucent sol;

[0060] Step 4: Connect the core electrode obtained in Step 1 to the positive terminal of the electrophoresis apparatus power supply, and connect a silver fiber with a diameter of 1 cm to the negative terminal. Insert the fiber into the sol in parallel, apply a voltage of 100V, perform electrophoretic deposition for 15 minutes, and then dry it in an 85℃ drying oven for 15 minutes to obtain the main fiber.

[0061] Step 5: Place the main fiber obtained in Step 4 and a carbon nanotube fiber in parallel, and assemble them into a fiber-shaped photodetector by twisting and winding them using a twisting machine.

Claims

1. A fibrous lead-free double perovskite photodetector and its fabrication method, characterized in that... The detector consists of a single element containing a fibrous core electrode-TiO2 nanorod array-chemical formula A. 2 B + M 3+ The detector is assembled by twisting and winding the main fiber of the X6 lead-free double perovskite thin film layer with another conductive fiber. The fabrication method of the detector is as follows: Step 1: Grow TiO2 nanorod arrays on fibrous core electrodes, with TiO2 nanorod lengths ranging from 50 to 500 nm; Step 2: Dissolve AX and B using a polar solvent. + X, M 3+ X3 and organic amine ligands were used to obtain precursor solutions with concentrations ranging from 0.1 to 10 mol / L; Step 3: Inject the precursor solution into a nonpolar solvent to obtain lead-free double perovskite sol; Step 4: Deposit a lead-free double perovskite film layer with a thickness of 100 nm to 2 μm on a nano-TiO2 array using electrophoretic deposition in a lead-free double perovskite sol to obtain the main fiber; Step 5: Twist and wind the main fiber obtained in Step 4 and another conductive fiber to assemble a fiber-shaped photodetector; Where: A is one or more of K, Rb, and Cs; B + For Li + Na + K + 、Rb + Cs + Ag + One or more of them; M 3+ For Al 3+ Ga 3+ In 3+ Sb 3+ Bi 3+ ,Sc 3+ Y 3+ One or more of the following; X is one or more of Cl, Br, and I.

2. The photodetector and its fabrication method according to claim 1, characterized in that... The fibrous core electrode uses one of carbon fiber, silver fiber, copper fiber, and carbon nanotube fiber.

3. The photodetector and its fabrication method according to claim 1, characterized in that... The conductive fiber uses one of the following: carbon fiber, silver fiber, copper fiber, and carbon nanotube fiber.

4. The photodetector and its fabrication method according to claim 1, characterized in that... The polar solvent is a mixture of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 1:1 to 1:

20.

5. The photodetector and its fabrication method according to claim 1, characterized in that... The volume ratio of the precursor solution to the nonpolar solvent is 1:10 to 1:1000.

6. The photodetector and its fabrication method according to claim 1, characterized in that... Organic amine ligands are primary amines with fewer than 15 carbon atoms.

7. The photodetector and its fabrication method according to any one of claims 1 and 5, characterized in that... The nonpolar solvent is one of toluene, chloroform, and n-hexane.

8. The photodetector and its fabrication method according to claim 1, characterized in that... The deposition voltage is 50~200V, the deposition time is 5~200min, and the distance between the electrodes is 0.5~5cm.

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