CN106966936A - A kind of preparation method of the water-soluble fluorescent orange silicon nano of high stability - Google Patents

Abstract

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the steps are as follows: adding pure hydrogen-terminated silicon nanoparticles and allylaminothiourea to anhydrous DMSO, using the method of freezing-pumping-dissolving cycle The air in the system was removed, and the system was heated to 100-180° C. in an Ar gas environment. After reacting for 3-15 hours, it was naturally cooled to room temperature, then centrifuged, and dried in vacuum to obtain thiourea-capped water-soluble orange fluorescent silicon nanoparticles. The invention adopts allylamine thiourea as a functional reagent, and synthesizes orange fluorescent thiourea-capped water-soluble silicon nanoparticles under high-temperature heating conditions. The silicon nanoparticle has the advantages of long emission wavelength (620nm), high luminous intensity, long fluorescence lifetime (42.6μs), good fluorescence stability, good water solubility and the like.

Description

A kind of preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles

technical field

The invention belongs to the technical field of nanomaterial preparation, and relates to a method for preparing functionalized silicon nanoparticles, in particular to a method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles.

Background technique

Silicon nanoparticles (SiNPs) have no (low) toxicity, good biocompatibility, strong photostability, high fluorescence quantum yield and wide fluorescence emission range (the fluorescence emission wavelength It can extend from the ultraviolet region to the near-infrared region) and other excellent properties, and is considered to be one of the most promising novel nanomaterials in medical imaging, microbial detection, clinical diagnosis and treatment (see Chan.Science, 1998 ,281:2016-2018; Ko.Nano Letters,2006,6:2318-2324; Kimura.Bioconjugate Chemistry,2010,21:436-444;Liao.Journal of Electronic Materials,2013,42:3445-3450; Chemistry Letters, 2013, 42:498-500; Roy. Langmuir, 2012, 28: 8244-8250; Kim. Angewandte Chemie International Edition, 2011, 50: 2317-2321; Kang. Advanced Materials, 2009, 21: 661-664. ) However, the currently synthesized hydrogen-terminated silicon nanoparticles (H-SiNPs) have disadvantages such as easy oxidation, poor photostability, poor water solubility, and low fluorescence quantum yield. Therefore, it is necessary to functionalize the surface to improve Its water solubility, optical properties and biocompatibility, etc.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned problems existing in H-SiNPs, and provide a method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, which significantly improves the water solubility and photostability of H-SiNPs.

Technical scheme of the present invention:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, first adopting high-temperature pyrolysis of hydrogen silsesquioxane (hydrosilsesquioxane, HSQ) method to obtain hydrogen-terminated silicon nanoparticles, and then under heating conditions Thiourea is a modifier that obtains the water-soluble silicon nanoparticles of thiourea capping, comprising the following steps:

1) Use a rotary evaporator to spin dry the solvent in the liquid Fox-17 to obtain white solid hydrogen silsesquioxane.

2) Hydrogen silsesquioxane is pyrolyzed in 5% H ₂ -95% Ar atmosphere at high temperature, cooled to room temperature and ground into khaki solid powder to obtain a Si/SiO _x mixture.

3) Pour the Si/SiO _x mixture into a polytetrafluoroethylene cup containing a freshly prepared etching solution, and after etching for a period of time in a fume hood at room temperature, a crude product of hydrogen-terminated silicon nanoparticles is obtained.

4) The H-SiNPs in the crude product were extracted with anhydrous toluene, and purified by centrifugation in an ethanol solution, and the centrifugal purification step was repeated to remove the etching solution as much as possible.

5) The H-SiNPs obtained after purification were dried in a vacuum oven for later use.

6) Add H-SiNPs and allylaminothiourea to anhydrous dimethyl sulfoxide, remove the air in the system by freezing-pumping-thawing cycle three times, and react at different temperatures for different times in an Ar gas environment Naturally cool to room temperature.

7) The product is centrifuged in an absolute ethanol solution and filtered in an aqueous solution to remove unreacted allylaminothiourea and hydrogen-terminated silicon nanoparticles, respectively.

8) After purification, the thiourea-capped NS-SiNPs were dried in a vacuum oven for later use.

The amount of hydrogen silsesquioxane used in the step 2) is 3.0 g.

The high temperature in the step 2) refers to 1150°C.

The etching time at high temperature in the step 2) is 1 h.

The composition of the etching solution in the step 3) is prepared according to the volume ratio HF:EtOH:H ₂ O=1:1:1, the mass fraction of HF used is 48%, and the amount ratio of Si/SiO _x to the etching solution For 300mg: 9mL.

In the step 3), the etching time is 1 h in a fume hood at room temperature.

The molar ratio of H-SiNPs to allylaminothiourea in step 6) is 1:5˜1:25.

The reaction temperature in the step 6) is 100-180°C.

The reaction time in the step 6) is 3 to 15 hours.

The rotation speed in the absolute ethanol in the step 7) is 1300rpm, the centrifugation time is 5min, and the centrifugation is repeated several times.

The filter membrane used for filtering in the step 7) has a diameter of 0.45 μm.

The drying temperature in the step 8) is 50° C., and the drying time is 12 hours.

The beneficial effects of the invention are: the invention adopts allylamine thiourea as a functional reagent, and synthesizes orange fluorescent thiourea-terminated water-soluble silicon nanoparticles under high-temperature heating conditions. The silicon nanoparticle has the advantages of long emission wavelength (620nm), high luminous intensity (PLQY: 13.5%), long fluorescence lifetime (42.6μs), good fluorescence stability, good water solubility and the like.

Description of drawings

FIG. 1 is a high-magnification electron micrograph of NS-SiNPs synthesized in Example 1.

FIG. 2 is the ultraviolet-visible absorption spectrum of H-SiNPs and NS-SiNPs synthesized in Example 1.

3 is a picture of the aqueous solution of H-SiNPs synthesized in Example 1 under sunlight and 302nm ultraviolet light.

4 is a picture of the aqueous solution of NS-SiNPs synthesized in Example 1 under sunlight and 302nm ultraviolet light.

Fig. 5 is the fluorescence excitation curve (E _m =620nm) and fluorescence emission curve (E _x =300nm) of the NS-SiNPs synthesized in Example 1.

Fig. 6 is a comparison chart of fluorescence emission curves (E _x =300nm) and quantum yields of H-SiNPs and NS-SiNPs synthesized in Example 1.

7 is the fluorescence lifetime spectrum of H-SiNPs and NS-SiNPs synthesized in Example 1.

FIG. 8 is a photostability graph of H-SiNPs and NS-SiNPs synthesized in Example 1. FIG.

detailed description

Example 1:

A preparation method of highly stable water-soluble fluorescent silicon nanoparticles, first adopting high-temperature pyrolysis of hydrogen silsesquioxane to obtain hydrogen-terminated silicon nanoparticles, and then synthesizing thiourea-terminated water-soluble silicon nanoparticles under heating conditions Nanoparticles, comprising the steps of:

1) Use a rotary evaporator to spin dry the solvent in the liquid Fox-17 to obtain white solid hydrogen silsesquioxane.

2) pyrolyze 3.0 g of hydrogen silsesquioxane in 5% H ₂ -95% Ar atmosphere at 1150°C for 1 hour at a high temperature of 18°C/min, cool to room temperature and grind it into a khaki solid powder to obtain Mixture of Si/ _SiOx .

3) 300mg Si/SiO _x was added into a polytetrafluoroethylene cup containing 9mL of newly prepared etching solution, and etched at room temperature in a fume hood for 1h to obtain a crude product of hydrogen-terminated silicon nanoparticles. The composition of the liquid is prepared according to the volume ratio HF:EtOH:H ₂ O=1:1:1, and the mass fraction of the HF is 48%.

4) The H-SiNPs in the crude product were extracted with anhydrous toluene, and centrifuged at 13000 rpm for 5 min in an ethanol solution. Repeat this centrifugal purification step to remove as much etching solution as possible.

5) The H-SiNPs obtained after purification were dried in a vacuum oven at 50°C for 12 hours, and set aside.

6) Add 30 mg of H-SiNPs and 450 mg of allylaminothiourea to 5 mL of anhydrous dimethyl sulfoxide, remove the air in the system by freezing-pumping-thawing cycle three times, and heat the system to 150°C, react for 9 hours and then cool to room temperature naturally.

7) The product is centrifuged in an absolute ethanol solution and filtered in an aqueous solution to remove unreacted allylaminothiourea and hydrogen-terminated silicon nanoparticles, respectively.

8) The thiourea-terminated silicon nanoparticles NS-SiNPs obtained after purification were dried in a vacuum oven at 50° C. for 12 hours, and set aside.

Figure 1 is a transmission electron microscope image of the synthesized NS-SiNPs, which shows that the NS-SiNPs are in the shape of spherical particles with a particle size of about 2.0nm.

Figure 2 is the UV-Vis absorption spectrum of synthesized H-SiNPs and NS-SiNPs, which shows that compared with H-SiNPs, the absorbance of NS-SiNPs is significantly enhanced, which is due to the surface of NS-SiNPs after doping. The number of conjugated groups increases.

Figure 3 is a photo of the synthesized H-SiNPs aqueous solution under sunlight and 302nm ultraviolet light irradiation. The figure shows that the synthesized H-SiNPs aqueous solution is relatively turbid, has poor water solubility, and emits red fluorescence under 302nm ultraviolet light irradiation. But the fluorescence intensity is relatively weak.

Figure 4 is a photo of the aqueous solution of the synthesized NS-SiNPs under fluorescent lamp and 302nm ultraviolet light. It emits orange fluorescence under 302nm ultraviolet light, and the fluorescence intensity is relatively strong.

Fig. 5 is the fluorescence excitation spectrogram (Em=620nm) and the fluorescence emission spectrogram (Ex=300nm) of the synthesized NS-SiNPs, shows in the figure: the optimum excitation wavelength of the synthetic silicon nanoparticle is 300nm, the optimum emission wavelength At 620nm, it emits orange fluorescence.

Figure 6 is a comparison chart of fluorescence emission spectra and quantum yields of synthesized H-SiNPs and NS-SiNPs, which shows that the fluorescence intensity and quantum yield of thiourea-capped silicon nanoparticles are significantly enhanced.

Figure 7 is the fluorescence lifetime spectrum of the synthesized H-SiNPs and NS-SiNPs, and the average fluorescence lifetimes of H-SiNPs and NS-SiNPs obtained by fitting calculations are 29.9 μs and 42.6 μs respectively, indicating that the silicon nanoparticles terminated by thiourea The fluorescence lifetime of Si nanoparticles is significantly longer than that of hydrogen-terminated Si nanoparticles, which may be due to the less surface defects of Si nanoparticles after functional modification.

Figure 8 is the photostability spectrum of the synthesized H-SiNPs and NS-SiNPs, which shows that compared with the hydrogen-terminated silicon nanoparticles, the photostability of the thiourea-terminated silicon nanoparticles is significantly enhanced.

Example 2:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, the difference is that the reaction temperature in step 6) is 100 ° C, and the silicon nanometers capped with thiourea are obtained. particle.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 3:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction temperature in step 6) is 120°C , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 4:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction temperature in step 6) is 140°C , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 5:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction temperature in step 6) is 160°C , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Embodiment 6:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction temperature in step 6) is 180°C , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Embodiment 7:

A method for preparing highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction time in step 6) is 3h, Thiourea-terminated silicon nanoparticles were prepared.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Embodiment 8:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction time in step 6) is 6h , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Embodiment 9:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction time in step 6) is 12h , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 10:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, and the preparation steps are basically the same as in Example 1, except that the reaction time in step 6) is 15h , prepared thiourea-terminated silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 11:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, the preparation steps are basically the same as in Example 1, and the difference is that the allylaminothiourea in step 6) The dosage is 150 mg to prepare thiourea-capped silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 12:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, the preparation steps are basically the same as in Example 1, and the difference is that the allylaminothiourea in step 6) The dosage is 300 mg to prepare thiourea-capped silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 13:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, the preparation steps are basically the same as in Example 1, and the difference is that the allylaminothiourea in step 6) The dosage is 600 mg to prepare thiourea-capped silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Example 14:

A preparation method of highly stable water-soluble orange fluorescent silicon nanoparticles, the preparation steps are basically the same as in Example 1, the preparation steps are basically the same as in Example 1, and the difference is that the allylaminothiourea in step 6) The amount used was 750 mg to prepare thiourea-capped silicon nanoparticles.

The fluorescence spectrum of the prepared thiourea-capped silicon nanoparticles is similar to that of Example 1.

Claims (5)

1. the preparation method of the water-soluble fluorescent orange silicon nano of a kind of high stability, first using high temperature pyrolysis hydrogen sesquialter silicon The method of oxygen alkane obtains the silicon nano of hydrogen end-blocking, then obtains thiocarbamide using allyl thiacetazone as dressing agent in a heated condition The water-soluble silicon nano-particle of end-blocking, comprises the following steps：

1) dried H-SiNPs and allylamine thiocarbamide are added in anhydrous dimethyl sulphoxide, using freezing-take out-molten circulation three times Method removing system in air, in Ar compression rings border under different temperatures react different time after naturally cool to room temperature；

2) product removes unreacted allyl respectively the centrifugation in ethanol solution and by way of filtering in aqueous The silicon nano of amine thiocarbamide and hydrogen end-blocking；

3) NS-SiNPs for blocking the thiocarbamide obtained after purification is dried in vacuum drying chamber, standby.

2. the preparation method of the water-soluble fluorescent orange silicon nano of high stability according to claim 1, its feature exists In：The step 1) in the preparation method of silicon nano that blocks of hydrogen be：Using Rotary Evaporators by liquid Fox-17 Solvent is spin-dried for, and obtains white solid hydrogen silsesquioxane；By hydrogen silsesquioxane in 5%H₂It is 1150 DEG C high in -95%Ar atmosphere Temperature is lower to be pyrolyzed, and is cooled to after room temperature and is ground to form khaki solid powder, obtains Si/SiO_xMixture.By Si/SiO_xMixing Thing is added in the polytetrafluoroethylene (PTFE) cup containing the etching liquid newly prepared, and is etched after a period of time, is obtained at room temperature in fume hood The crude product of the silicon nano blocked to hydrogen.The H-SiNPs in crude product is extracted using dry toluene, and in ethanol Centrifugal purification in solution；The steps by centrifugation is repeated to remove etching liquid as far as possible；The H-SiNPs obtained after purification is dry in vacuum Dried in dry case, it is standby.

3. the preparation method of the water-soluble fluorescent orange silicon nano of high stability according to claim 1, its feature exists In：The step 1) in the mol ratio of H-SiNPs and allylamine thiocarbamide be 1:5~1:25.

4. the preparation method of the water-soluble fluorescent orange silicon nano of high stability according to claim 1, its feature exists In：The step 1) in reaction temperature be 100~180 DEG C.

5. the preparation method of the water-soluble fluorescent orange silicon nano of high stability according to claim 1, its feature exists In：The step 1) in reaction time be 3~15h.