A two-dimensional conductive metal-organic framework-based surface-enhanced raman scattering active substrate and a preparation method thereof

Abstract

The application belongs to the field of material chemistry and Raman, and particularly relates to a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal organic framework and a preparation method thereof. A two-dimensional Zn-OHPTP nanomaterial is used as a surface-enhanced Raman scattering active substrate, and a SiO2 crystal is used as a carrier to prepare a surface-enhanced Raman scattering active substrate material based on a two-dimensional conductive metal organic framework. The preparation is simple and fast, the cost is low, and the surface-enhanced Raman scattering active substrate material has a significant Raman enhancement signal.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material chemistry and Raman, and particularly relates to a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal-organic framework and a preparation method thereof. BACKGROUND

[0002] Surface-enhanced Raman spectroscopy (SERS) is an ultra-sensitive sensing technology that can provide rich vibrational information for molecules adsorbed on the surface of an enhancement material. Generally speaking, traditional SERS substrates can be divided into two basic substrate types: metal and semiconductor substrates. However, due to the high cost, complex preparation, and inconvenience for long-term storage, metal and semiconductor substrates are subject to many limitations in actual application processes.

[0003] Conductive metal-organic frameworks (CMOFs) are a new type of organic-inorganic hybrid supramolecular material that has appeared in recent years. As a popular material in recent years, CMOFs have become a promising candidate in various energy-related fields, such as electrocatalysis, supercapacitors, thermoelectric materials, field effect transistors, and the like, due to their excellent charge transport behavior and high surface area. Although CMOFs have been widely used in many fields, their application as a Raman enhancement substrate in the field of Raman has not been reported. With further development of research on CMOFs, it is also important to expand their potential application range beyond traditional applications by utilizing their new characteristics.

[0004] SERS technology is a promising field for metal-organic frameworks (MOFs). In previous studies, MOFs materials, due to their three-dimensional network structure, usually act as a scaffold for noble metal particles, and only the noble metal particles have enhanced Raman signals in the process. In contrast, the SERS effect of MOFs as a Raman substrate has not been fully explored. In the occasional SERS effect observed with MOFs as a substrate, the Raman enhancement factor (EF) value caused by MOFs is very low, only in the range of 60-120.

[0005] In view of this, in order to solve the above problems, the present application discloses a preparation method of a two-dimensional conductive metal-organic framework as a surface-enhanced Raman scattering substrate material. And with rhodamine (R6G) as a signal probe molecule, it is proved that CMOFs can be used as a SERS substrate for molecular sensing, with remarkable Raman enhancement effect. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art and provide a surface-enhanced Raman scattering active substrate material with a wide range and excellent comprehensive performance, and a preparation method thereof.

[0007] To achieve the above object, the application adopts the following technical solutions:

[0008] A two-dimensional conductive metal-organic framework-based surface-enhanced Raman scattering active substrate and a preparation method thereof, comprising the following steps:

[0009] (1) Preparation of two-dimensional conductive metal-organic framework (Zn-OHPTP) nanomaterial: dissolve zinc acetate dihydrate and octahydroxytetraphenylbenzene (OHPTP) in deionized water, and then stir for a certain time.

[0010] (2) The solution obtained in (1) is ultrasonically treated for a certain time, and then a solution of N,N-dimethylformamide (DMF) with a suitable concentration is added.

[0011] (3) The solution sample obtained in (2) is ultrasonically treated for a certain time, and then placed in an oven for heating reaction.

[0012] (4) The powder sample obtained in (3) is centrifuged to obtain Zn-OHPTP nanomaterial, and washed with deionized water and acetone for several times.

[0013] (5) Preparation of SiO2 wafer: ultrasonically treat the commercially available SiO2 wafer in ultrapure water to obtain a clean SiO2 wafer.

[0014] (6) Preparation of surface-enhanced Raman scattering active substrate: drop coat Zn-OHPTP dispersion on the surface of SiO2 wafer, stand and dry, to obtain a two-dimensional conductive metal-organic framework-based surface-enhanced Raman scattering active substrate.

[0015] The step (1) is specifically as follows: the preparation process of OHPTP has been disclosed, and the specific process is referred to the literature <Near IR Bandgap Semiconducting 2D Conjugated Metal-Organic Framework with Rhombic Lattice and High Mobility> synthesis.

[0016] Further, in step (1), the concentration of zinc acetate dihydrate is 0.008 mol L-1, the concentration of OHPTP is 0.016 mol L-1, and the stirring time is 3 minutes.

[0017] Further, step (2) is specifically as follows: the ultrasonic treatment time is 5 minutes, and the concentration of DMF solution is 1 mL.

[0018] Further, step (3) is specifically as follows: the ultrasonic time is 3 minutes, and the heating temperature is 85 degrees Celsius.

[0019] Further, step (4) is specifically as follows: centrifugation of the powder sample obtained in (3) at 8000 r / min for 5 minutes to obtain Zn-OHPTP nanomaterial, and the number of washing times of deionized water and acetone is 5.

[0020] Further, step (5) is specifically as follows: the ultrasonic treatment time is 10 minutes.

[0021] Further, step (6) is specifically as follows: after ultrasonic treatment of the Zn-OHPTP dispersion liquid for 10 minutes, 10 muL of the Zn-OHPTP dispersion liquid is uniformly dropped and coated on the surface of the SiO2 wafer, and the same is placed at 37 degrees Celsius for drying, to obtain a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal organic framework.

[0022] The present application has the following advantages:

[0023] (1) The preparation process is simple, and the cost is low, without the need of expensive reagents and advanced instruments.

[0024] (2) The present application constructs a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal organic framework, simplifies the preparation process of a traditional Raman substrate, and can be quickly prepared under the condition of existing raw materials.

[0025] (3) The surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal organic framework has a Raman enhancement factor (EF) of 10 5 for Rhodamine dye (R6G), which is equivalent to that of noble metals without "hot spots" and the EF of the recently reported zinc oxide semiconductor. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A transmission electron microscope characterization diagram of Zn-OHPTP;

[0027] Figure 2 An X-ray diffraction spectrum of Zn-OHPTP;

[0028] Figure 3 A resistance characterization diagram of Zn-OHPTP;

[0029] Figure 4 An optical picture of a surface-cleaned SiO2 wafer;

[0030] Figure 5 An optical picture of a surface-enhanced Raman scattering active substrate based on Zn-OHPTP;

[0031] Figure 6 A Raman enhancement spectrum of a surface-enhanced Raman scattering active substrate based on Zn-OHPTP for R6G. DETAILED DESCRIPTION

[0032] The following describes a specific embodiment of a two-dimensional conductive metal organic framework-based surface-enhanced Raman scattering active substrate and a preparation method thereof in combination with the accompanying drawings.

[0033] The preparation method of the two-dimensional conductive metal organic framework-based surface-enhanced Raman scattering active substrate is as follows: first, zinc acetate dihydrate and octahydroxytetraphenylbenzene (OHPTP) are dissolved in deionized water, and then stirred for 3 minutes. Subsequently, the above solution is ultrasonically treated for 5 minutes, and then 1 mL of N,N-dimethylformamide solution is added. Then, the obtained solution sample is ultrasonically treated for 3 minutes, and then placed in an oven at 85 degrees Celsius for heating reaction overnight. The Zn-OHPTP nanomaterial is obtained by centrifugation, and washed with deionized water and ethanol for five times. A commercially available SiO2 wafer is ultrasonically treated in ultrapure water to obtain a surface-cleaned SiO2 wafer. The Zn-OHPTP dispersion liquid is drop-coated on the surface of the SiO2 wafer, and then placed and dried, to obtain the two-dimensional conductive metal organic framework-based surface-enhanced Raman scattering active substrate.

[0034] Example 1

[0035] Two-dimensional conductive metal organic framework (Zn-OHPTP) nanomaterial:

[0036] (1) First, 15 mg of zinc acetate dihydrate and 12 mg of octahydroxytetraphenylbenzene (OHPTP) are dissolved in 3 mL of deionized water, and then stirred for 5 minutes.

[0037] (2) The solution obtained in (1) is ultrasonically treated for 5 minutes, and then 1 mL of N,N-dimethylformamide solution (DMF) is added.

[0038] (3) The solution sample obtained in (2) is ultrasonically treated for 3 minutes, and then placed in an oven at 85 degrees Celsius for heating reaction overnight.

[0039] (4) The powder sample obtained in (3) is centrifuged to obtain the Zn-OHPTP nanomaterial, and washed with deionized water and acetone for five times, and the transmission electron microscopy characterization is as follows Figure 1 .

[0040] XRD test of two-dimensional conductive metal organic framework (Zn-OHPTP) nanomaterial:

[0041] The Zn-OHPTP material obtained in Example 1 is placed and dried at 60 degrees Celsius, and then the powder sample is uniformly pressed on the surface of a SiO2 wafer, and the pressed material is placed in an X-ray diffractometer for testing, to obtain the X-ray diffraction pattern of the Zn-OHPTP as follows Figure 2 .

[0042] Conductivity test of two-dimensional conductive metal organic framework (Zn-OHPTP) nanomaterial:

[0043] (1) First, 20 mg of Zn-OHPTP nanomaterials were pressed into tablets by a tablet press to obtain a tablet-shaped Zn-OHPTP module with a diameter of 5 mm and a thickness of 2 mm.

[0044] (2) Then, the tablet-shaped Zn-OHPTP module was connected to gold wires with silver glue to obtain a test precursor.

[0045] (3) The resistance of the tablet-shaped Zn-OHPTP test precursor was detected by a conductivity meter, and the average conductivity was calculated to be 0.05 S / m. The resistance characterization is as follows Figure 3 .

[0046] Preparation of SiO2 wafer:

[0047] Commercial SiO2 wafers were ultrasonically cleaned in ultrapure water to obtain clean SiO2 wafers as follows Figure 4 .

[0048] Preparation of surface-enhanced Raman scattering active substrate:

[0049] After ultrasonicating the Zn-OHPTP dispersion for 10 minutes, 10 μL of the Zn-OHPTP dispersion was uniformly dropped and coated on the surface of the SiO2 wafer, and it was left to dry, thereby obtaining a surface-enhanced Raman scattering active substrate based on two-dimensional conductive metal-organic frameworks as follows Figure 5 .

[0050] Raman enhancement test of R6G by the surface-enhanced Raman scattering active substrate based on Zn-OHPTP:

[0051] (1) First, 10 μL of a 10 -5 mol L R6G solution was dropped on the active substrate, and it was left to stand for 2 hours, and then the surface of the substrate was rinsed with deionized water to remove excess R6G.

[0052] (2) Then, under 532 nm laser irradiation, the Raman scattering performance of the Zn-OHPTP surface-enhanced Raman scattering active substrate for R6G was tested using a Raman spectrometer. The experimental results are as follows Figure 6 , and the SCNNSs / GaN heterostructure has a significantly enhanced Raman signal, proving its excellent performance as a Raman scattering active substrate.

Claims

1. A method for preparing a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal-organic framework, comprising the following steps: (1) preparing a two-dimensional conductive metal-organic framework Zn-OHPTP nanomaterial: dissolving zinc acetate dihydrate and prepared octahydroxytetraphenylbenzene OHPTP in deionized water, and then stirring; (2) ultrasonic treating the solution obtained in (1), and then adding a N, N-dimethylformamide solution DMF; (3) ultrasonic treating the solution sample obtained in (2), and then placing it in an oven for heating reaction; (4) centrifuging the powder sample obtained in (3) to obtain a Zn-OHPTP nanomaterial, and washing it with deionized water and acetone; (5) preparing a SiO 2 wafer: ultrasonic treating a commercially available SiO 2 wafer in ultrapure water to obtain a surface-cleaned SiO 2 wafer; (6) preparing a surface-enhanced Raman scattering active substrate: dropping and coating a Zn-OHPTP dispersion liquid on the surface of the SiO 2 wafer, and then standing and drying, to obtain a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal-organic framework. The step (2) is specifically as follows: the ultrasonic treatment time is 5 minutes, and the DMF solution concentration is 1 mL. The step (3) is specifically as follows: the ultrasonic time is 3 minutes, and the heating temperature is 85 degrees Celsius. The step (4) is specifically as follows: centrifuging the powder sample obtained in (3) at 8000 r / min for 5 minutes to obtain a Zn-OHPTP nanomaterial, and washing it with deionized water and acetone for 5 times. The step (5) is specifically as follows: the ultrasonic treatment time is 10 minutes. The step (6) is specifically as follows: after ultrasonic treating the Zn-OHPTP dispersion liquid for 10 minutes, uniformly dropping and coating 10 μL of the Zn-OHPTP dispersion liquid on the surface of the SiO 2 wafer, and then standing and drying it in an oven at 37 degrees Celsius, to obtain a surface-enhanced Raman scattering active substrate based on a two-dimensional conductive metal-organic framework. 8.The surface-enhanced Raman scattering active substrate obtained by the method according to any one of claims 1-7. ​ 2. The method of claim 1, wherein: The concentration of zinc acetate dihydrate in step (1) was 0.008 mol L -1 and the concentration of OHPTP was 0.016 mol L -1 with a stirring time of 3 minutes.

3. The method of claim 1, wherein: ​ 4. The method of claim 1, wherein: ​ 5. The method of claim 1, wherein: ​ 6. The method of claim 1, wherein: ​ 7. The method of claim 1, wherein: ​ ​

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