Method for preparing vanadium pentoxide film by sol-gel method
1. A method for preparing a vanadium pentoxide film by a sol-gel method is characterized by comprising the following steps:
preparation of V2O5Sol:
adding VOCl into absolute ethyl alcohol3Liquid is evenly stirred and stands for 5min to 20min to obtainVO(OC2H5)3Solution, under stirring, to VO (OC)2H5)3Dropwise adding distilled water into the solution, and uniformly stirring to obtain V2O5Sol and final ageing to obtain aged V2O5Sol;
the VOCl3The molar ratio of the liquid to the absolute ethyl alcohol is 1 (100-400); the VOCl3The molar ratio of the liquid to the distilled water is 1 (5-50);
secondly, deposition and film formation:
firstly, aging V by a film forming method2O5Forming a film on a substrate by the sol, and then carrying out heat treatment for 0.5 to 1.5 hours at the temperature of 100 to 300 ℃ to obtain a single layer V2O5A film;
the matrix is obtained by sequentially ultrasonically cleaning in distilled water, absolute ethyl alcohol and acetone and drying;
and secondly, repeating the step two for a plurality of times to obtain V from nanometer to micron2O5A film.
2. The method for preparing vanadium pentoxide thin film according to claim 1, wherein the stirring at 50-200 rpm in step one is carried out to VO (OC)2H5)3Distilled water was added dropwise to the solution.
3. The method for preparing vanadium pentoxide thin film according to claim 1, wherein in the first step, the vanadium pentoxide thin film is added to VO (OC) under stirring at a dropping speed of 0.05-2 mL/s2H5)3Distilled water was added dropwise to the solution.
4. The method for preparing the vanadium pentoxide film by the sol-gel method according to claim 1, wherein the aging in the first step is standing aging in a cool and dry place for 12-36 h.
5. The method for preparing vanadium pentoxide thin film according to claim 1, wherein the substrate in the second (r) step is glass, silicon wafer, mica, quartz, titanium dioxide thin film, ITO thin film, AZO thin film or polymer material.
6. The method for preparing vanadium pentoxide thin film according to claim 1, wherein the single layer V is prepared in step two2O5The thickness of the film is 20 nm-30 nm.
7. The method for preparing vanadium pentoxide thin film according to claim 1, wherein the film forming method in the second step is a pulling method, a spin coating method or a spraying method.
8. The method for preparing vanadium pentoxide thin film according to claim 7, wherein the film forming method is a Czochralski method, and the substrate is vertically inserted into the aged V2O5After being inserted into the sol for 1-5 min, the substrate is vertically pulled at a speed of 1-10 cm/min.
9. The method for preparing vanadium pentoxide thin film according to claim 7, wherein the film-forming method is a spin coating method, and the aged V is subjected to a spin coating method2O5The sol is fully coated on a substrate, and then the coated substrate is fixed on a turntable of a rotary coating machine and is rotated for 30 to 90 seconds under the condition that the rotating speed is 1000 to 3000 rpm.
10. The method for preparing vanadium pentoxide thin film according to claim 7, wherein the film-forming method is a spraying method, and the aged V is2O5The sol is sprayed uniformly onto the substrate using a sprayer.
Background
V2O5Capable of reacting with lithium to form lithium vanadate and, owing to its particular layered structure, V2O5When the film is used as a cathode material of a lithium ion battery, the lithium ion battery can have a long service lifeThe battery capacity is higher than that of the current commercial application, and the battery has wide application potential. V2O5The adsorption of gas molecules on the surface of the film causes the state of the surface to change: the conductivity of the vanadium oxide layer is changed through the action of hydrogen bonds and the vanadium oxide layer. V2O5The film can also be used for gas-sensitive and moisture-sensitive sensors. V2O5Has semiconductor-metal phase transition, is in metal state at a temperature of 257 deg.C or higher, has high reflectivity and low transmissivity to infrared light, and can prevent laser from damaging infrared detector, so its phase transition characteristic can make V be2O5The film can be used for laser protection devices.
At present V2O5The film preparation method comprises a vacuum evaporation method, a sputtering method, pulse laser cladding, a Sol-Gel method (Sol-Gel) and the like, wherein the film prepared by the vacuum evaporation method and the sputtering method has more oxygen vacancies, poor process stability and low deposition rate, and usually contains low-valence vanadium oxide; the conventional sol-gel method such as the melt quenching method requires high-temperature melting V2O5Powder, long aging time, long preparation period, rough and porous film and low quality.
Disclosure of Invention
The invention aims to solve the problem that V prepared by the existing vacuum evaporation method and sputtering method2O5The film has the problems of more oxygen vacancies, poor process stability, low deposition rate and low-valence vanadium oxide content; preparation of V by sol-gel method2O5High temperature melting V is required for film2O5The problems of long aging time, long preparation period, rough and porous film and low quality of the film generally exist, and the method for preparing the vanadium pentoxide film by the sol-gel method is provided.
A method for preparing a vanadium pentoxide film by a sol-gel method comprises the following steps:
preparation of V2O5Sol:
adding VOCl into absolute ethyl alcohol3Evenly stirring the liquid, and standing for 5-20 min to obtain VO (OC)2H5)3Solution, under stirring, to VO(OC2H5)3Dropwise adding distilled water into the solution, and uniformly stirring to obtain V2O5Sol and final ageing to obtain aged V2O5Sol;
the VOCl3The molar ratio of the liquid to the absolute ethyl alcohol is 1 (100-400); the VOCl3The molar ratio of the liquid to the distilled water is 1 (5-50);
secondly, deposition and film formation:
firstly, aging V by a film forming method2O5Forming a film on a substrate by the sol, and then carrying out heat treatment for 0.5 to 1.5 hours at the temperature of 100 to 300 ℃ to obtain a single layer V2O5A film;
the matrix is obtained by sequentially ultrasonically cleaning in distilled water, absolute ethyl alcohol and acetone and drying;
and secondly, repeating the step two for a plurality of times to obtain V from nanometer to micron2O5A film.
The invention has the beneficial effects that:
VOCl of the invention3Reacting with absolute ethyl alcohol to obtain vanadium alkoxide, forming stable solution system, adding deionized water, and reacting to obtain V2O5. And the film has less oxygen vacancy and does not have low-valence vanadium oxide.
The film prepared by the invention is V2O5The sol is deposited on the surface of a matrix through physical adsorption and chemical adsorption, and is formed into gel through dehydration and desolventization after drying, so that the surface is compact, smooth and flat, the quality is stable, and the sol can be deposited on the matrix with complex properties.
The film thickness obtained by single adsorption deposition is relatively thin, so the film thickness can be controlled by controlling the cycle deposition times, and the film deposited by the sol-gel method has relatively high growth speed and relatively stable growth speed.
The reaction can be carried out at normal temperature, no complex equipment is needed, the preparation process is simple, the preparation period is short, and the energy consumption is low.
The invention relates to a method for preparing a vanadium pentoxide film by a sol-gel method.
Drawings
FIG. 1 shows a V prepared by two steps of the example2O5AFM three-dimensional photographs of the films;
FIG. 2 shows a V prepared by two steps of the example2O5X-ray photoelectron spectroscopy of the thin film;
FIG. 3 shows a V prepared by the second step of the example2O5SEM photograph with 100000 times magnification of film;
FIG. 4 shows a V prepared by the second step of the example2O5Fine mapping of binding energy of V2p and O1s analyzed by thin film XPS;
FIG. 5 shows the V prepared in two steps of the example2O5The film was photographed at (a) 1:3:250, (b) 1:4:250, (c) 1:5:250, (d) 1:10:250, and (e) 1:20: 250.
Detailed Description
The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.
The first embodiment is as follows: the method for preparing the vanadium pentoxide film by the sol-gel method according to the embodiment is carried out according to the following steps:
preparation of V2O5Sol:
adding VOCl into absolute ethyl alcohol3Evenly stirring the liquid, and standing for 5-20 min to obtain VO (OC)2H5)3Solution, under stirring, to VO (OC)2H5)3Dropwise adding distilled water into the solution, and uniformly stirring to obtain V2O5Sol and final ageing to obtain aged V2O5Sol;
the VOCl3The molar ratio of the liquid to the absolute ethyl alcohol is 1 (100-400); the VOCl3The molar ratio of the liquid to the distilled water is 1 (5-50);
secondly, deposition and film formation:
firstly, aging V by a film forming method2O5Forming a film on a substrate by the sol, and then carrying out heat treatment for 0.5 to 1.5 hours at the temperature of 100 to 300 ℃ to obtain a single layer V2O5A film;
the matrix is obtained by sequentially ultrasonically cleaning in distilled water, absolute ethyl alcohol and acetone and drying;
and secondly, repeating the step two for a plurality of times to obtain V from nanometer to micron2O5A film.
The specific implementation method firstly cleans the substrate, and the key factor influencing the film forming quality is V2O5Sol solution quality. VOCl3Reacting with ethanol to generate VO (OC)2H5)3And hydrolysis to form V2O5The sol process is carried out in a stirrer to ensure that the reaction is fully and uniformly carried out. The mol ratio of vanadium oxychloride, water and absolute ethyl alcohol has great influence on the viscosity of the sol, the viscosity is also an important factor for controlling the film forming quality and the deposition speed, after the sol is formed, sol particles are adsorbed on a substrate by lifting, spin coating, spraying and the like, and after the sol is gelated by heat treatment, V is formed2O5A film. The main factors influencing the film forming thickness of the film are the concentration and the cycle number of the precursor solution, and the main factors influencing the film quality are the cleaning quality and the heat treatment process.
The beneficial effects of the embodiment are as follows:
VOCl of the present embodiment3Reacting with absolute ethyl alcohol to obtain vanadium alkoxide, forming stable solution system, adding deionized water, and reacting to obtain V2O5. And the film has less oxygen vacancy and does not have low-valence vanadium oxide.
The film prepared in this embodiment is V2O5The sol is deposited on the surface of a matrix through physical adsorption and chemical adsorption, and is formed into gel through dehydration and desolventization after drying, so that the surface is compact, smooth and flat, the quality is stable, and the sol can be deposited on the matrix with complex properties.
In the embodiment, the thickness of the film obtained by single adsorption deposition is relatively thin, so that the thickness of the film can be controlled by controlling the number of times of cyclic deposition, and meanwhile, the film deposited by the sol-gel method has relatively high growth speed and relatively stable growth speed.
The reaction can be carried out at normal temperature, no complex equipment is needed, the preparation process is simple, the preparation period is short, and the energy consumption is low.
The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: in the first step, VO (OC) is added under the stirring condition of 50-200 rpm2H5)3Distilled water was added dropwise to the solution. The rest is the same as the first embodiment.
The third concrete implementation mode: this embodiment is different from the first or second embodiment in that: in the first step, under the stirring condition, the VO (OC) is added with the dropwise adding speed of 0.05-2 mL/s2H5)3Distilled water was added dropwise to the solution. The other is the same as in the first or second embodiment.
The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: and the aging in the step one is standing and aging for 12-36 h at a cool and dry place. The others are the same as the first to third embodiments.
The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: and the substrate in the second step is glass, a silicon wafer, mica, quartz, a titanium dioxide film, an ITO film, an AZO film or a polymer material. The rest is the same as the first to fourth embodiments.
The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: step two2O5The thickness of the film is 20 nm-30 nm. The rest is the same as the first to fifth embodiments.
The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: the film forming method in the second step is a pulling method, a spin coating method or spraying. The others are the same as the first to sixth embodiments.
The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: the film forming method is a Czochralski method, and a substrate is vertically inserted and agedV of2O5After being inserted into the sol for 1-5 min, the substrate is vertically pulled at a speed of 1-10 cm/min. The rest is the same as the first to seventh embodiments.
The specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: the film forming method is a spin coating method, and the aged V2O5The sol is fully coated on a substrate, and then the coated substrate is fixed on a turntable of a rotary coating machine and is rotated for 30 to 90 seconds under the condition that the rotating speed is 1000 to 3000 rpm. The other points are the same as those in the first to eighth embodiments.
The detailed implementation mode is ten: the present embodiment differs from one of the first to ninth embodiments in that: the film forming method is a spraying method, and the aged V is treated2O5The sol is sprayed uniformly onto the substrate using a sprayer. The other points are the same as those in the first to ninth embodiments.
The following examples were used to demonstrate the beneficial effects of the present invention:
the first embodiment is as follows:
a method for preparing a vanadium pentoxide film by a sol-gel method comprises the following steps:
preparation of V2O5Sol:
to 50mL of absolute ethanol was added 0.34mL of VOCl3Stirring the liquid evenly, standing for 10min to obtain VO (OC)2H5)3The solution was added dropwise at a rate of 0.1mL/s to VO (OC) under stirring at 75rpm2H5)3Dropwise adding distilled water into the solution until the volume of the added distilled water reaches 1.24mL, and uniformly stirring to obtain V2O5Dissolving in sol, covering with aluminum foil for dust prevention, standing in shade and dry place for aging for 24 hr to obtain aged V2O5Sol;
secondly, deposition and film formation:
inserting the matrix vertically into the aged V2O5Inserting into the sol for 1min, vertically pulling the substrate at 5cm/min, vertically suspending in a drying oven, and heating at 200 deg.CTreating for 30min to obtain single layer V2O5A film;
②, repeating the second step for 4 times to obtain V2O5A film.
In step one, 0.34mL of VOCl was added to 50mL of absolute ethanol3The concentration of the liquid in the absolute ethyl alcohol is 0.04mol/L by conversion. Converted said VOCl3Liquid: distilled water: the molar ratio of the absolute ethyl alcohol is 1:20: 250;
step two prepared V2O5The film was orange-yellow.
The matrix in the second step is pretreated according to the following steps: immersing the substrate in distilled water, ultrasonically oscillating and cleaning for 10min at the temperature of 25 ℃ to remove water-soluble ions adsorbed on the surface of the glass, then immersing the substrate in absolute ethyl alcohol, ultrasonically oscillating and cleaning for 10min at the temperature of 25 ℃, washing polar organic matters on the surface, immersing the substrate in acetone, ultrasonically oscillating and cleaning for 10min at the temperature of 25 ℃, washing non-polar organic matters, and finally drying the substrate in an oven at the temperature of 80 ℃ for later use.
The substrate in the second step is high-purity quartz glass with the size of 40mm multiplied by 10 mm.
Monolayer V was prepared in one step two of the test example2O5Film thickness is about 20nm, step two said V2O5The film thickness is 94nm, which shows that the film deposited by the sol-gel method has higher growth speed and more stable growth speed.
FIG. 1 shows a V prepared by two steps of the example2O5AFM three-dimensional photographs of the films; as can be seen from the figure, the surface of the film is almost free of granular protrusions, the characteristic dimension is very small, and the surface is very flat.
FIG. 2 shows a V prepared by two steps of the example2O5X-ray photoelectron spectroscopy of the thin film; as can be seen, the composition V: O of the deposited layer is 1:2.35, which is close to the ideal 1:2.5, indicating that the film has fewer oxygen vacancies and is stoichiometrically pure.
FIG. 3 shows a V prepared by the second step of the example2O5Film holderSEM photograph 100000 times larger; as can be seen from the figure, the whole surface of the film is compact, flat and smooth, and the coating quality is very high.
FIG. 4 shows a V prepared by the second step of the example2O5Fine mapping of binding energy of V2p and O1s analyzed by thin film XPS; as can be seen, V2p only appears in one state, V2p3/2The peak positions are 517.04eV and V2p1/2At 524.35eV, this is the electronic state of vanadium valence 5, indicating that the film is V2O5No low-valent vanadium oxide is present.
Example two: the difference between the present embodiment and the first embodiment is: the VOCl3Liquid: distilled water: the molar ratio of the absolute ethyl alcohol is 1:3:250, 1:4:250, 1:5:250, 1:10:250 and 1:20: 250; in the second step, the first step is repeated for 1 time to obtain V2O5A film. The rest is the same as the first embodiment.
FIG. 5 shows the V prepared in two steps of the example2O5Physical photographs of the films (a) at 1:3:250, (b) at 1:4:250, (c) at 1:5:250, (d) at 1:10:250, (e) at 1:20: 250; the deposited layers are orange yellow, the characteristics are similar, and the atomic ratio V: O is 1: 2.2-2.5 when the component analysis is carried out on the sample.
Example three: the difference between the present embodiment and the first embodiment is: step two, aging the V2O5The sol is coated on a substrate, and then the coated substrate is fixed on a turntable of a rotary coating machine and rotated for 45s under the condition that the rotating speed is 2000 rpm. The rest is the same as the first embodiment.
Example four: the difference between the present embodiment and the first embodiment is: the substrate in the second step is a silicon wafer with the size of 40mm multiplied by 10 mm. The rest is the same as the first embodiment.
