The preparation method of the indium oxide nanocrystalline that pattern is controlled
Technical field
The present invention relates to the preparation method of the controlled indium oxide nanocrystalline of a kind of pattern, or rather the present invention be a kind of be raw material with the indium compound, utilize simple solvent-thermal method to prepare the method for Indium sesquioxide nano cubic block or nanometer rod, belong to the nano material category.
Background technology
Indium sesquioxide (In
2O
3) be a kind of important semiconductor material, its direct band gap width approximately is 3.6eV, indirect band gap is about 2.6eV.Indium sesquioxide is widely used in microelectronic, as opto-electronic device, and solar cell, liquid-crystal display and gas sensor etc.Pure Indium sesquioxide has more weak conductivity.Its film visible light transmissivity significantly improves after mixing Sn, and since the sixties in 20th century, the Indium sesquioxide of mixing Sn just becomes main transparent conductive material, does not still have other materials can replace it so far.After entering the seventies, be accompanied by the development of liquid-crystal display, the research and development that are used for the indium tin oxide of transparency electrode have further promoted the research to Indium sesquioxide again.Except being used as transparent conductive film material, Indium sesquioxide also has important application aspect gas sensor, and it has stability preferably as gas sensor.After Indium sesquioxide made nano-scale, its specific surface area increases greatly, make the height of particle surface potential barrier and the virtual resistance of thickness and crystal grain neck all play noticeable change, the grain surface activity improves greatly, so just make its absorption, desorption to gas, and redox reaction can under lower temperature, carry out, thereby reduction working temperature, shorten the time of response, for example, utilize solvent thermal in conjunction with high temperature annealing preparation the Indium sesquioxide nano cubic block, the length of side has high air-sensitive degree about 100-200nm.
The Indium sesquioxide of doped transition metal ions is a kind of dilute magnetic semiconductor simultaneously, promptly partly substitutes the formed particular semiconductor of non magnetic positively charged ion by magnetic transition-metal ion or rare earth ion in semi-conductor.Dilute magnetic semiconductor shows some unique character at aspects such as physics, crystallography, optics, electricity, thereby is with a wide range of applications.The dilute magnetic semiconductor of nano-scale has potential to use on microelectronic device, spin electric device simultaneously.In recent years, the Indium sesquioxide material of doped magnetic transition metal ion or rare earth ion has caused extensive studies interest, the indium oxide film and the block materials that have had bibliographical information to synthesize to have room-temperature ferromagnetic, and do not meet the report of the Indium sesquioxide nano material of crossing metal ion mixing.
At present, the preparation nano indium oxide mainly is high temperature vapour phase processes and liquid phase method.Wherein liquid phase method is temperature required lower, be beneficial to scale operation, and the liquid phase method in the present bibliographical information mainly comprises the precipitator method and the hot method of hydrothermal/solvent, in order to obtain the finished product, all need through calcining step, owing to calcine, the pattern of sample is difficult to control simultaneously, subside easily, and the crystal that forms is a polycrystalline.
Solvent-thermal method is in the container of a sealing, and reactor heating makes its temperature of reaction surpass the boiling point of solvent.Solvent-thermal method has been widely used in the preparation of nano material recently.The advantage of this method is a normally highly crystalline of resulting product, good dispersity, easy control of reaction conditions simultaneously.By the screening solvent, the conditioned reaction temperature, reaction times and precursor concentration are utilized solvent-thermal method directly to synthesize the Indium sesquioxide nano cubic block and the nanometer rod of uniform not doping of pattern and metal ion mixing, and are had high productive rate.
Summary of the invention
At above-mentioned present situation, the object of the present invention is to provide a kind of monodispersed nanocrystalline method of pattern controllable oxidization indium that undopes or mix of simple solvent-thermal method produced in high yields of utilizing.The present invention implements by following technological process:
Plain indium oxide nanocrystalline is to be presoma with the methyl alcohol of the compound of indium or ethanolic soln, alcoholysis in methyl alcohol that contains NaOH or KoH or ethanolic soln, and the suspension after the alcoholysis is put into reactor and is formed by pure reaction for preparation then;
The mass percentage concentration of indium is 0.5%-10% in the described presoma;
The mass percentage concentration of described NaOH or KoH is 0.4%-7.5%; The pure thermal response temperature of reactor is 200-250 ℃.
Concrete preparation process is:
A) compound with a kind of indium in indium nitrate, indium chloride or the indium acetate joins in methyl alcohol or the ethanol, magnetic agitation and generate the presoma that contains indium;
B) sodium hydroxide or potassium hydroxide are dissolved in methyl alcohol or the ethanol, are mixed with the alkaline alcoholic solution,
C) at room temperature the alcoholic solution of step (b) preparation is slowly splashed in the alcoholic solution of the indium compound that step (a) produces, constantly stirs simultaneously, carry out alcoholysis, form white precipitate or jelly,
D) white precipitate that step (c) is obtained or jelly change in the reactor together with methyl alcohol or alcohol solvent, sealing;
E) reactor is heated to 200-250 ℃ of pure thermal response; Be cooled to room temperature again;
F) collecting precipitation thing, with distilled water and dehydrated alcohol wash respectively with vacuum filtration after filter cake in 80 ℃, oven dry is sieved and is prepared into indium oxide nanocrystalline.
The alcoholysis rear suspension liquid accounts for the 60%-90% of inner liner of reaction kettle volume; The reaction soaking time is 10-30h.
The heating of reactor puts it into baking oven or retort furnace is implemented, and temperature rise rate is 5-10 ℃/min.
Use methanol solution to make the nanocrystalline single crystal structure that is at last, be the cubic block of rule, and be transparent in the visible region.
Adulterated indium oxide nanocrystalline then is that the compound with a kind of indium in indium nitrate, indium chloride or the indium acetate joins in methyl alcohol or the ethanolic soln, and containing transition metal ion magnetic agitation mixing is made presoma simultaneously; The mass percentage concentration of indium is 0.5-10% in the presoma; Adulterated transition metal ion be among Fe, Co, Ni, Cu, Cr and the Mn one or both, the doping of transition metal ion is 0.1-10at%.All the other steps are with above-mentioned (b)~(f) and associated description.
The undoping or mix In of preparation method provided by the invention preparation
2O
3Nanocrystalline characteristic is:
(1) use methyl alcohol do the solvent preparation plain Indium sesquioxide product X-ray powder diffraction figure as shown in Figure 1.In Fig. 1, all diffraction peaks can be demarcated is the In of cube phase
2O
3, and meet fine (JCPDS No.71-2194) with literature value, the lattice parameter a=1.012nm that calculates according to figure, with theoretical value a=1.0117nm coincide fine.Typical microstructure such as Fig. 2 of the not doped indium oxide of the present invention preparation, shown in 3, most ofs nanocrystalline be the cubic block of rule, the about 60nm of size, dispersed better, nothing is reunion obviously.From the high-resolution-ration transmission electric-lens photo as can be seen, nanocrystalline is single crystal structure, the well-crystallized.Fig. 4 is the not room temperature uv-visible absorption spectra of doped indium oxide of synthetic, and as can be seen from the figure, basic not absorption illustrates that synthetic Indium sesquioxide nano cubic block of the present invention is transparent at visible region in the visible region.
(2) use ethanol do the solvent preparation plain Indium sesquioxide product X-ray powder diffraction figure as shown in the figure.In Fig. 5, all diffraction peaks can be demarcated is the In of cube phase
2O
3, meet with literature value (JCPDS No.71-2194).Fig. 6 is the TEM photo that ethanol is made the Indium sesquioxide of solvent preparation, and sample is a nanometer rod from scheming as can be seen, diameter about 10-15nm, length about 80-120nm, good dispersion.
(3) the containing transition metal ionic indium oxide nanocrystalline with preparation method's preparation provided by the present invention demonstrates good M-H characteristic, for example, the stereoscan photograph of the 3.4at% iron doped indium oxide of use the present invention preparation as shown in Figure 7, overwhelming majority particle has kept a cube bulk, favorable dispersity, the length of side is about 80nm.Fig. 8 is the room temperature uv-visible absorption spectra of 3.4at% iron doped indium oxide, and as can be seen from the figure, sample only has poor absorption at 470nm at visible region.Fig. 9 is the room temperature M-H curve of this sample, and show sample has tangible room-temperature ferromagnetic among the figure, illustrates that the adulterated Indium sesquioxide of iron has the potential application as dilute magnetic semiconductor.
In sum, utilizing the present invention to prepare the Indium sesquioxide nano cubic block has the following advantages:
(1) methyl alcohol and ethanol are cheap solvents, and building-up process is simple simultaneously, do not need calcining, thereby have avoided grain growth and hard aggregation phenomenon.
(2) product favorable dispersity, pattern is very even; Without any need for tensio-active agent;
(3) utilize method provided by the invention, be easy to control the pattern of preparing the indium oxide nanocrystalline that undopes: cubic block or nanometer rod;
(4) be beneficial to the adulterated Indium sesquioxide nano material of preparation, the adulterated Indium sesquioxide nano material (1-10at%) in certain doping content of using method provided by the invention to prepare keeps the pattern of nano cubic block or nanometer rod; And by regulating doping, pure hot time, pure hot temperature, the magnetic property of controlled doping Indium sesquioxide nano cubic block or nanometer rod.(seeing embodiment 4,5 for details)
(5) performances such as the light of product, magnetic are beneficial to regulation and control, have higher productive rate (>80%) simultaneously.
Description of drawings
Fig. 1 methyl alcohol is made solvent, the XRD figure spectrum of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
Fig. 2 methyl alcohol is made solvent, the TEM pattern of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
Fig. 3 methyl alcohol is made solvent, the HRTEM photo of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
Fig. 4 methyl alcohol is made solvent, the room temperature uv-visible absorption spectra of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
Fig. 5 ethanol is made solvent, the XRD figure spectrum of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
Fig. 6 ethanol is made solvent, the TEM photo of 250 ℃ of plain Indium sesquioxide products of obtaining of reaction 25h.
The SEM pattern of the adulterated Indium sesquioxide product of 3.4at%Fe that 250 ℃ of reactions of Fig. 7 25h obtains.
The room temperature uv-visible absorption spectra of the adulterated Indium sesquioxide product of 3.4at%Fe that 250 ℃ of reactions of Fig. 8 25h obtains.The room temperature M-H curve of the adulterated Indium sesquioxide product of 3.4at%Fe that 250 ℃ of reactions of Fig. 9 25h obtains.
The room temperature M-H curve of the adulterated Indium sesquioxide product of 6.1at%Co that 250 ℃ of reactions of Figure 10 20h obtains
The 2.8at%Cu that 250 ℃ of reactions of Figure 11 20h obtains, the room temperature M-H curve of the adulterated Indium sesquioxide product of 3.9at%Cr
Embodiment
Further specify characteristics and the obvious improvement that the present invention gives prominence to below by specific embodiment.But the present invention only is confined to embodiment by no means
Embodiment 1, with 1.6g In (NO
3)
34.5H
2O (99.5%) is dissolved in the 40ml methyl alcohol, and carries out magnetic agitation, in addition 1.2gNaOH is dissolved in the other 40ml methyl alcohol, and the latter is slowly splashed in the former solution, has white precipitate and produces.After treating titration fully, continue to stir 1 hour, the suspension with gained all changes in the water heating kettle that volume is 100ml again, sealing, put into baking oven or muffle furnace and be warming up to 250 ℃, be incubated 10 hours, then naturally cooling with the speed of 5 ℃/min, take out reactor, with faint yellow precipitate with deionized water and each several of absolute ethanol washing of obtaining, last suction filtration dries by the fire 10h with filter cake at 80 ℃, grind, can obtain final product.(Fig. 1-4)
Embodiment 2, with 1.6g In (NO
3)
34.5H
2O (99.5%) is dissolved in the 40ml ethanol, and carries out magnetic agitation, in addition 1.2gNaOH is dissolved in the other 40 ml ethanol, and the latter is slowly splashed in the former solution, has white precipitate and produces.After treating titration fully, continue to stir 1 hour, the suspension with gained all changes in the water heating kettle that volume is 100ml again, sealing, put into baking oven or muffle furnace and be warming up to 200 ℃, be incubated 30 hours, then naturally cooling with the speed of 8 ℃/min, take out reactor, with faint yellow precipitate with deionized water and each several of absolute ethanol washing of obtaining, last suction filtration dries by the fire 10h with filter cake at 80 ℃, grind, can obtain final product.(Fig. 5-6)
Embodiment 3, with 0.8g In (NO
3)
34.5H
2O (99.5%) and 0.04gFe (NO
3)
39H
2O is dissolved in the 20ml methyl alcohol, and carry out magnetic agitation, in addition 0.6gNaOH is dissolved in other the 20ml methyl alcohol, the methanol solution of NaOH is slowly splashed in the former solution, has faint yellow precipitation to occur, treat titration fully after, continue to stir 1 hour, suspension with gained all changes in the water heating kettle that volume is 100ml again, and sealing is put into baking oven or muffle furnace and is warming up to 250 ℃ with the speed of 5 ℃/min, be incubated 25 hours, naturally cooling takes out reactor then, with nattierblue precipitate with deionized water and each several of absolute ethanol washing that obtains, last suction filtration, filter cake at 80 ℃ of baking 10h, is ground, can obtain final product.(Fig. 7-9)
Embodiment 4, with 0.8g In (NO
3)
34.5H
2O (99.5%) and 0.08gCo (NO
3)
26H
2O is dissolved in the 20ml methyl alcohol, and carry out magnetic agitation, in addition 0.6gNaOH is dissolved in the 20ml methyl alcohol, the methanol solution of NaOH is slowly splashed in the former solution, has brown precipitation to occur, treat titration fully after, continue to stir 1 hour, suspension with gained all changes in the water heating kettle that volume is 100ml again, and sealing is put into baking oven or muffle furnace and is warming up to 250 ℃ with the speed of 5 ℃/min, be incubated 20 hours, naturally cooling takes out reactor then, with nattierblue precipitate with deionized water and each several of absolute ethanol washing that obtains, last suction filtration, filter cake at 80 ℃ of baking 10h, is ground, can obtain final product.(Figure 10)
Embodiment 5, with 0.8g In (NO
3)
34.5H
2O (99.5%) and 0.07g Cr (NO
3)
39H
2O, 0.03gCu (NO
3)
23H
2O is dissolved in the 20ml methyl alcohol, and carry out magnetic agitation, in addition 0.8gNaOH is dissolved in the 20ml methyl alcohol, the methanol solution of NaOH is slowly splashed in the former solution, has nattierblue precipitation to occur, treat titration fully after, continue to stir 1 hour, suspension with gained all changes in the water heating kettle that volume is 100ml again, and sealing is put into baking oven or muffle furnace and is warming up to 200 ℃ with the speed of 5 ℃/min, be incubated 25 hours, naturally cooling takes out reactor then, with nattierblue precipitate with deionized water and each several of absolute ethanol washing that obtains, last suction filtration, filter cake at 80 ℃ of baking 10h, is ground, can obtain final product.(Figure 11)