Ag/TiS 2 layered composite substrate with strong SERS activity in near infrared by SPR and preparation method thereof
阅读说明：本技术 一种SPR在近红外具有强SERS活性的Ag/TiS2分层复合基底及其制备方法 (Ag/TiS 2 layered composite substrate with strong SERS activity in near infrared by SPR and preparation method thereof ) 是由 张小龙 张永军 王雅新 陈雷 赵晓宇 张帆 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种SPR在近红外具有强SERS活性的Ag/TiS_2分层复合基底及其制备方法,属于复合纳米功能材料技术领域。本发明的目的是改善TiS_2表面增强拉曼散射活性,获得有较强拉曼活性的基底,本发明所提供的复合基底为Ag和TiS_2的复合材料,该复合结构是将Ag和TiS_2通过分层溅射的方式沉积在200nm六方密排阵列的聚苯乙烯小球上获得,其中Ag厚度为10nm,TiS_2厚度为2～10nm,具有在红外区可调的SPR特性,通过改变TiS_2的厚度就可以实现SPR的精确调控。(The invention discloses an Ag/TiS 2 layered composite substrate with strong SERS activity in near infrared of SPR and a preparation method thereof, belonging to the technical field of composite nano functional materials and aiming at improving the surface enhanced Raman scattering activity of TiS 2 and obtaining a substrate with strong Raman activity.)
1. The Ag/TiS 2 layered composite substrate with strong SERS activity in near infrared of SPR is a composite material of Ag and TiS 2, and the composite structure is obtained by depositing Ag and TiS 2 on 200nm hexagonal close-packed polystyrene spheres in a layered sputtering mode, wherein the thickness of Ag is 10nm, and the thickness of TiS 2 is 2-10 nm.
2. The preparation method of the Ag/TiS 2 layered composite substrate with the SPR in the near infrared region and strong SERS activity according to claim 1 comprises the following steps:
1) Cleaning a silicon wafer;
2) Preparing a hexagonal close-packed polystyrene microsphere array;
3) Preparing an Ag/TiS 2 layered nano structure, preparing the Ag/TiS 2 layered nano structure by using a vacuum deposition system, putting the prepared two-dimensional template into a sputtering chamber, wherein the vacuum degree is 2 multiplied by 10 -4 Pa, the working pressure is 0.6Pa, the gas flow is 25sccm, the sputtering rate of Ag is 10nm/min, the sputtering time is 1min, the sputtering rate of TiS 2 is 2nm/min, and the sputtering time is 1 min-5 min, and finally preparing the Ag/TiS 2 surface enhanced Raman scattering active substrate of which the SPR is in a near infrared region.
3. The method for preparing the Ag/TiS 2 layered composite substrate with strong SERS activity in the near infrared by SPR according to claim 2, wherein the specific steps in the step 1) are as follows:
and putting the silicon wafer into a beaker, and adding a mixed solution of ammonia water, hydrogen peroxide and deionized water in a volume ratio of 1:2:6 into the beaker respectively. And (3) placing the beaker on a scorching table, heating to boil, keeping for 5-10 min, cooling, pouring out the liquid, and repeatedly performing ultrasonic treatment for 15min by using deionized water and absolute ethyl alcohol in sequence.
4. The method for preparing the Ag/TiS 2 layered composite substrate with strong SERS activity in the near infrared by SPR according to claim 2, wherein the specific steps of the step 2) are as follows:
Mixing polystyrene pellets with the diameter of 200nm and absolute ethyl alcohol according to the volume ratio of 1:1, uniformly dispersing the polystyrene pellets through ultrasonic treatment, dripping the dispersed polystyrene pellets on a massive silicon wafer by using a liquid transfer gun to uniformly distribute dispersion liquid on the silicon wafer, slowly and obliquely sliding the massive silicon wafer into a vessel with a stable liquid surface to form a closely-arranged polystyrene pellet array on the water surface, finally slowly fishing up the pellet array floating on the water surface by using the cleaned silicon wafer, and absorbing water and drying for later use.
5. The method for preparing the Ag/TiS 2 layered composite substrate with strong SERS activity in near infrared by SPR of claim 2, wherein the sputtering time of TiS 2 is 1 min.
Technical Field
The present invention belongs to the field of composite nanometer functional material technology.
Background
In recent decades, Localized Surface Plasmon Resonance (LSPR) characteristics in noble metal nanoparticles have been studied, however, LSPR has also been found in semiconductors such as Cu 2-x S, ZnO, etc. as the doping amount of the semiconductor increases, LSPR moves to the near infrared region Zhu et al have been shown by theoretical analysis and experiments for the first time that near infrared region LSPR characteristics also exist in semi-metal TiS 2.
disclosure of Invention
in order to improve the surface enhanced Raman scattering activity of TiS 2 and obtain a substrate with stronger Raman activity, the invention discloses a near-infrared Ag/TiS 2 surface enhanced Raman scattering active substrate with SPR, the substrate is a composite material of Ag and TiS 2, and the composite structure is obtained by depositing Ag and TiS 2 on 200nm hexagonal close-packed array polystyrene spheres in a layered sputtering mode, wherein the thickness of Ag is 10nm, and the thickness of TiS 2 is 2-10 nm.
The SPR of the Ag/TiS 2 active substrate in a near infrared region is regulated and controlled by changing the sputtering time of TiS 2, and the enhancement of SERS is realized by coupling the local surface plasmon resonance effect of Ag and the plasmon resonance of semimetal TiS 2.
The preparation steps of the composite material are as follows:
(1) And cleaning the silicon wafer. And putting the silicon wafer into a beaker, and adding a mixed solution of ammonia water, hydrogen peroxide and deionized water in a volume ratio of 1:2:6 into the beaker respectively. And (3) placing the beaker on a scorching table, heating to boil, keeping for 5-10 min, cooling, pouring out the liquid, and repeatedly performing ultrasonic treatment for 15min by using deionized water and absolute ethyl alcohol in sequence.
(2) An array of hexagonal close-packed polystyrene spheres was prepared. Mixing polystyrene pellets with the diameter of 200nm and absolute ethyl alcohol according to the volume ratio of 1:1, uniformly dispersing the polystyrene pellets through ultrasonic treatment, dripping the dispersed polystyrene pellets on a massive silicon wafer by using a liquid transfer gun to uniformly distribute dispersion liquid on the silicon wafer, slowly and obliquely sliding the massive silicon wafer into a vessel with a stable liquid surface to form a closely-arranged polystyrene pellet array on the water surface, finally slowly fishing up the pellet array floating on the water surface by using the cleaned silicon wafer, and absorbing water and drying for later use.
(3) The method comprises the steps of preparing an Ag/TiS 2 layered nano structure, preparing an Ag/TiS 2 layered nano structure by using a vacuum deposition system, putting a prepared two-dimensional template into a sputtering chamber, wherein the vacuum degree is 2 multiplied by 10 -4 Pa, the working pressure is 0.6Pa, the sputtering rate of 25sccm of Ag is 10nm/min, the sputtering time is 1min, the sputtering rate of TiS 2 is 2nm/min, the sputtering time is 1 min-5 min, and preferably 1min, and finally preparing the Ag/TiS 2 composite nano structure of the SPR in a near infrared region.
The invention has the beneficial effects that:
1. The Ag/TiS 2 layered nano structure prepared by the magnetron sputtering technology has the SPR characteristic of being adjustable in an infrared region, and the preparation method is simple and short in experimental period.
2. Precise control of SPR can be achieved by varying the thickness of TiS 2.
3. The Ag/TiS 2 layered nano-structure can be widely applied to biological detection, optical devices and communication windows.
drawings
FIG. 1 SEM image of layered nanostructure of Ag/TiS 2 (Ag 10nm/TiS 2 2nm)
FIG. 2 SEM image of layered nanostructure of Ag/TiS 2 (Ag 10nm/TiS 2 5nm)
FIG. 3 SEM image of layered nanostructure of Ag/TiS 2 (Ag 10nm/TiS 2 10nm)
FIG. 4 UV absorption spectra of Ag/TiS 2 layered nanostructures
FIG. 5 UV absorption spectra of single layer Ag and TiS 2.
FIG. 6 Raman spectra of Ag/TiS 2 layered nanostructures
FIG. 7 Raman spectra of single layer Ag and TiS 2.
Detailed Description
The technical solution of the present invention is further explained and illustrated below by way of specific examples.
(1) Cleaning a silicon wafer, cutting the silicon wafer into small silicon wafers of 2 multiplied by 2cm 2, putting the small silicon wafers into a beaker, respectively adding mixed solution of ammonia water, hydrogen peroxide and deionized water with the volume ratio of 1:2:6 into the beaker, putting the beaker on a scorching table, heating to boil, keeping the temperature for 5-10 min, pouring out the liquid after cooling, and repeatedly carrying out ultrasonic treatment for 15min by alternately using the deionized water and absolute ethyl alcohol.
(2) an array of hexagonal close-packed polystyrene spheres was prepared. Mixing polystyrene pellets with the diameter of 200nm and absolute ethyl alcohol according to the volume ratio of 1:1, uniformly dispersing the polystyrene pellets through ultrasonic treatment, dripping the dispersed polystyrene pellets on a massive silicon wafer by using a liquid transfer gun to uniformly distribute dispersion liquid on the silicon wafer, slowly and obliquely sliding the massive silicon wafer into a vessel with a stable liquid surface to form a closely-arranged polystyrene pellet array on the water surface, finally slowly fishing up the pellet array floating on the water surface by using the cleaned silicon wafer, and absorbing water and drying for later use.
(3) The method comprises the steps of preparing an Ag/TiS 2 layered nano structure, preparing an Ag/TiS 2 layered nano structure by using a vacuum deposition system, putting a prepared two-dimensional template into a sputtering chamber, wherein the vacuum degree is 2 multiplied by 10 -4 Pa, the working pressure is 0.6Pa, the gas flow is 25sccm, the sputtering rate of Ag is 10nm/min, the sputtering time is 1min, the sputtering rate of TiS 2 is 2nm/min, and the sputtering time is 1min, 2min, 2.5min or 5min respectively.
The Ag/TiS 2 composite nano-substrate is shown in figures 1-3, and as the TiS 2 sputtering time is prolonged, the surface roughness of the nano-structure is gradually reduced, and the size of the gap is also gradually reduced.
The present example used ultraviolet absorption spectroscopy to test the absorption spectra of Ag/TiS 2 nanomaterials, where SPR red-shifts from near infrared to infrared as the time of sputtering of TiS 2 increases, as shown in fig. 4, the absorption performance of Ag/TiS 2 nanomaterials is superior to that of single layer Ag and TiS 2 (fig. 5), and its SPR is at a greater wavelength, as shown in fig. 6 and 7, when excitation light is irradiated on the surface of the composite nanostructure, the SERS signal of Ag/TiS 2 2nm 2 nanomaterials is strongest, thus it can be seen that as the thickness of TiS 2 increases, its SERS activity gradually decreases, mainly because the excitation wavelength of 633nm is insufficient to excite the SPR in infrared.