The preparation method of bismuth sulfide whisker and the bismuth sulfide whisker for preparing
Technical field:
The present invention relates to the field of chemical synthesis, be specifically related to preparation method and the product of bismuth sulfide whisker.
Background technology:
As the V-VI semiconductor compound, bismuth sulfide shows brand-new application prospect because its good photoelectricity, photosensitive, infrared characteristic and thermoelectric effect etc. are subject to extensive concern at electronic applications.Studies show that, along with the reduction of material dimension, quantum size effect, quantum Interference, quantum tunneling effect, coulomb blockade effect etc. have significant impact to light, electricity, magnetic, heat, the mechanical property of material.The one dimension semiconductor material has played the effect of interconnection and functional unit in the making of electronics, opto-electronic device, be widely used in photoelectric component, as making photodiode, room temperature field-effect transistor (FETs), quantum wire/quantum dot laser etc.Therefore, preparation one dimension semiconductor material has become one of focus in the semiconductor material applied research.1998, reported on Mater.Lett. the 35th volume 116-119 page or leaf that employing ethanol makes solvent, solvent thermal is synthesized the bismuth sulfide micron bar, but the particle size were of the method preparation is inhomogeneous; In addition, 2007, reported on J.Cryst.Growth the 306th volume 159-165 page or leaf that the auxiliary solvent-thermal method of tensio-active agent prepares bismuth sulfide nano-rod, yet this method need to be added organic solvent.At the beginning of 2008, the contriver delivers its in advance achievement in research article at Ceramics Internatioal the 34th volume 249-251, report adopts potassium hydroxide (0.025M) as the bar-shaped crystallite of mineralizer Hydrothermal Synthesis bismuth sulfide, can obtain mean diameter 100~200nm, the bar-shaped crystallite of the bismuth sulfide of mean length 10um (photo is referring to Fig. 2 c)), yet regrettably, because product is very responsive to the mineralizer consumption, controlled relatively poor in the preparation process, the product form homogeneity that obtains is slightly poor, can not obtain the comparatively bismuth sulfide whisker of homogeneous of size and length.
Whisker (Whiskers) is a kind of fibrous single crystal, and the transverse section is close to consistent, and the external and internal compositions height is complete, and length-to-diameter ratio is generally more than 5~1000, and diameter is usually between 100nm~100 μ m; Be compared to traditional bismuth sulfide crystallite, the luminescent properties of bismuth sulfide whisker is more outstanding, have good mechanical property, good consistency, good chemical stability and regenerability, its distinctive one-dimentional structure has played the effect of interconnection and functional unit in the making of electronics, opto-electronic device, be widely used in photoelectric component.At present, there is no the open source literature of preparation bismuth sulfide whisker.
Summary of the invention:
The object of the present invention is to provide a kind of preparation method of bismuth sulfide whisker.The method can obtain the bismuth sulfide whisker of excellent performance.
The present invention is with thiocarbamide CS (NH
2)
2With Bismuth trinitrate be raw material, take LiOH as mineralizer and distilled water consist of the hydro-thermal presoma; Carry out hydro-thermal reaction 16h in 200 ℃ scope, the synthetic precipitated product that obtains is the bismuth sulfide whisker.
LiOH concentration in the described hydro-thermal presoma is 1.0~1.5M, is preferably 1.0M.
Concrete, bismuth sulfide crystal whisker preparation method key step is as follows:
1) preparation hydro-thermal presoma: 1: 2 in molar ratio, with Bi (NO
3)
35H
2O and CS (NH
2)
2Mix, add LiOH solid and distilled water by setting concentration;
2) hydro-thermal reaction: transfer in the teflon-lined stainless steel autoclave after the hydro-thermal presoma at room temperature stirred 1h, the filling volume accounts for 50%, then carries out hydro-thermal reaction;
3) washing is dry: leach throw out behind distilled water wash and absolute ethanol washing, the dry target product bismuth sulfide whisker that gets in 70 ℃ vacuum drying oven.
Wherein, described step 3) adopt distilled water and absolute ethanol washing: the distilled water wash number of times is 3 times, and the absolute ethanol washing number of times is 3 times.
Can obtain the bismuth sulfide whisker by above-mentioned preparation method.
Described bismuth sulfide whisker is for mean diameter is that 200~300nm, length are 20 μ m or above bismuth sulfide whisker.Most preferred, for be uniformly dispersed, mean diameter is about 250nm, length is about the bismuth sulfide whisker of 20 μ m.
Adopt above scheme, the present invention proposes with LiOH first as mineralizer, and hydrothermal method is synthesized the bismuth sulfide whisker.By control temperature of reaction and reaction times condition, the concentration of regulating mineralizer realizes that crystallization phases forms and the control growth of microscopic appearance.Adopt 1.0M LiOH as mineralizer, under 200 ℃ of temperature hydro-thermal reaction 16h can make be uniformly dispersed, mean diameter is about 250nm, length is about the bismuth sulfide whisker of 20 μ m.The method mineralizer concentration and consumption are easy to regulation and control, and by the whisker good uniformity that the Hydrothermal Synthesis process obtains, the product pattern is controlled, is fit to be applied to suitability for industrialized production.
Description of drawings:
Fig. 1 is under different concns LiOH mineralizer condition, 200 ℃, the Bi of 16h hydro-thermal reaction preparation
2S
3The SEM picture of sample: (a) 0M (not adding mineralizer), (b) 0.5M, (c) 1.0M, and (d) 1.5M.
Fig. 2 is under the different hydrothermal reaction conditions, the Bi that hydrothermal method is prepared
2S
3The SEM picture of sample: (a) the LiOH mineralizer of 1.0M, 120 ℃ of reaction 16h; (b) the LiOH mineralizer of 1.0M, 160 ℃ of reaction 16h; (c) the KOH mineralizer of 0.025M, 200 ℃ of reaction 15h.
Fig. 3 is 200 ℃, the Bi of 16h hydrothermal method preparation
2S
3The XRD spectra of sample: (a) do not add mineralizer; (b) the LiOH mineralizer of adding 1.0M.
Fig. 4 is under different concns mineralizer condition, 200 ℃, the Bi of 16h hydro-thermal reaction preparation
2S
3The fluorescence spectrum figure of sample (PL spectrogram): (a) 0M (not adding mineralizer); (b) 0.5M; (c) 1.0M.
Embodiment:
The technical solution adopted in the present invention principle: select thiocarbamide CS (NH
2)
2With the metal Bismuth trinitrate be raw material, take LiOH as mineralizer and distilled water consist of hydro-thermal presoma system.Under suitable hydrothermal temperature and reaction times condition, the concentration of regulating mineralizer realizes Bi
2S
3The product crystallization phases forms and the control of microscopic appearance is grown.Utilize the inventive method, can obtain mean diameter between 200~300nm, length 20 μ m or more than, size uniform is without the bismuth sulfide whisker of agglomeration.
For obtaining the bismuth sulfide whisker, the present invention selects Bi (NO
3)
35H
2O and CS (NH
2)
2Be reaction raw materials, take LiOH as mineralizer, with H
2O is the hydro-thermal reaction medium.Its preparation process is:
Take by weighing 0.002mol Bi (NO
3)
35H
2O and 0.004mol CS (NH
2)
2Mix, its mol ratio is 1: 2, adds LiOH solid and 50ml distilled water, makes the concentration of LiOH in the mixture solution (hydro-thermal presoma) in the 0.5-1.0M scope.Said mixture is transferred in the 100ml teflon-lined autoclave after at room temperature stirring 1h.In being 120-200 ℃ scope, temperature carries out hydro-thermal reaction 16h.Precipitated product is through distilled water wash 3 times, and behind the absolute ethanol washing 3 times, dry 4h gets black powder in 70 ℃ vacuum drying oven.Product is the Bi of oblique side's phase through X-ray diffraction (XRD) Analysis and Identification
2S
3, product microscopic crystalline pattern uses sem observation.
Example 1:
Take by weighing 0.002mol Bi (NO
3)
35H
2O (0.9701 gram) and 0.004mol CS (NH
2)
2(0.3045 gram) mixes, and its mol ratio is 1: 2, adds LiOH solid 1.049 gram and 50ml distilled water, and the concentration that makes LiOH in the mixture solution is 0.5M.Getting and transfer in the 100ml teflon-lined autoclave after 50ml said mixture (hydro-thermal presoma) at room temperature stirs 1h, is to carry out hydro-thermal reaction 16h, precipitation separation product under 200 ℃ in temperature.Precipitated product is behind distilled water wash 3 times, absolute ethanol washing 3 times, and dry 4h gets the black powder product in 70 ℃ vacuum drying oven.This black powder is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3Sem observation shows: product B i
2S
3The black powder major part is 100-500nm, is about the whisker of 10 μ m and the crystallite of small part granulometric composition by diameter.Shown in Fig. 1 (b).This example product form is made mineralizer, the Bi of 200 ℃ of hydro-thermal reaction 15h with the KOH that uses 0.025M
2S
3The product plesiomorphism is referring to Fig. 2 (c).
Example 2:
Take by weighing 0.002mol Bi (NO
3)
35H
2O and 0.004mol CS (NH
2)
2Mix, its mol ratio is 1: 2, adds LiOH solid 2.098 gram and 50ml distilled water, and the concentration that makes LiOH in the mixture solution is that 1.0M forms the hydro-thermal presoma.Getting and transfer in the 100ml teflon-lined autoclave after the 50ml said mixture at room temperature stirs 1h, is to carry out hydro-thermal reaction 16h, precipitation separation product under 200 ℃ in temperature.Precipitated product is behind distilled water wash 3 times, absolute ethanol washing 3 times, and dry 4h gets the black powder product in 70 ℃ vacuum drying oven.Product is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3, shown in Fig. 3 (b).Sem observation shows: product B i
2S
3Black powder by be uniformly dispersed, mean diameter is 250nm, the whisker of length about by 20 μ m formed.Shown in Fig. 1 (c).The product that this example obtains is Bi
2S
3Whisker, whisker size is even, and without agglomeration, morphology is also ideal, so the present embodiment is the top condition that the present invention synthesizes.
Example 3:
All the other conditions are identical with embodiment 2, and wherein the concentration of LiOH is 1.5M in the hydro-thermal presoma.The black powder product that obtains is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3, sem observation shows: Bi
2S
3The product major part by diameter be about 200~300nm, the whisker that is about 20 μ m forms, homogeneity is (but not as good as example 2 products) better, and only have few part particle to exist.Shown in Fig. 1 (d).
Example 4:
Take by weighing 0.002mol Bi (NO
3)
35H
2O and 0.004mol CS (NH
2)
2Mix, its mol ratio is 1: 2, adds LiOH solid 2.098 gram and 50ml distilled water, and the concentration that makes LiOH in the mixture solution is 1.0M.Get and transfer in the 100ml teflon-lined autoclave after the 50ml said mixture at room temperature stirs 1h.Reaction 16h under hydrothermal temperature is 120 ℃.Precipitated product is behind distilled water wash 3 times, absolute ethanol washing 3 times, and dry 4h gets black powder in 70 ℃ vacuum drying oven.Product is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3Sem observation shows: Bi
2S
3The product major part is about 100~500nm, is about the whisker of 3~10 μ m and the crystallite of part granulometric composition, shown in Fig. 2 (a) by diameter.This example product form is made mineralizer, the Bi of 200 ℃ of hydro-thermal reaction 15h with the KOH that uses 0.025M
2S
3The product plesiomorphism is referring to Fig. 2 (c).
Example 5:
Take by weighing 0.002mol Bi (NO
3)
35H
2O and 0.004mol CS (NH
2)
2Mix, its mol ratio is 1: 2, adds LiOH solid 2.098 gram and 50ml distilled water, and the concentration that makes LiOH in the mixture solution is 1.0M.Get and transfer in the 100ml teflon-lined autoclave after the 50ml said mixture at room temperature stirs 1h.Reaction 16h under hydrothermal temperature is 160 ℃.Precipitated product is behind distilled water wash 3 times, absolute ethanol washing 3 times, and dry 4h gets black powder in 70 ℃ vacuum drying oven.Product is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3Sem observation shows: Bi
2S
3In the product particle crystallite quantity relatively example 4 reduce to some extent, most of be about 100~500nm, be about whisker and the small part granulometric composition of 2~15 μ m by diameter.Shown in Fig. 2 (b).
Example 6:
Take by weighing 0.002mol Bi (NO
3)
35H
2O and 0.004mol CS (NH
2)
2Mix, its mol ratio is 1: 2, adds in the 50ml distilled water, transfers in the 100ml teflon-lined autoclave after at room temperature stirring 1h.Reaction 16h under hydrothermal temperature is 200 ℃.Precipitated product is through distilled water wash 3 times, and behind the absolute ethanol washing 3 times, dry 4h gets black powder in 70 ℃ vacuum drying oven.Product is accredited as the Bi of oblique side's phase through X-ray diffraction (XRD)
2S
3, shown in Fig. 3 (a).Sem observation shows: Bi
2S
3The product pattern is irregular, and major part is the reunion bulk shape, and only a few is elongated bar-shaped, and size approximately is about 1 μ m.Shown in Fig. 1 (a).This example explanation in the identical situation of other experiment condition, then is difficult to obtain Bi without mineralizer LiOH adding
2S
3Whisker.
Performance test:
Adopt Fluorolog-3 fluorescence analyser (USA) at room temperature to measure respectively bismuth sulfide powder (example 6 products), bismuth sulfide crystallite (example 1 product, contain the bismuth sulfide particle) and the fluorescence spectrum of bismuth sulfide whisker (example 2 products), its luminescent properties detected.Wherein bismuth sulfide crystallite and bismuth sulfide whisker make respectively as mineralizer auxiliary water thermal response with LiOH.
Referring to Fig. 4, shown different-shape Bi
2S
3Powder fluorescence spectrum figure (PL spectrogram).Fig. 4 shows, excites down at identical excitation wavelength 330nm, and bismuth sulfide powder launching centre a) is 410nm, and bismuth sulfide crystallite b) and bismuth sulfide whisker c) launching centre be 414nm, red shift has occured in launching centre.And add the prepared bismuth sulfide crystallite of mineralizer b) and bismuth sulfide whisker c) the luminous strength ratio Direct Hydrothermal react that to make bismuth sulfide powder intensity a) high; The bar-shaped crystallite b of bismuth sulfide) luminescent properties is better than inhomogeneous reunion block powder luminescent properties a) of microscopic crystalline pattern, bismuth sulfide whisker c) luminescent properties be better than again Rod-like shape crystallite b).This shows, the luminescent properties of bismuth sulfide powder is relevant with its microscopic crystalline shape characteristic, and the luminescent properties of bismuth sulfide whisker is best.
In the above-mentioned test, crystallite selects example 1 product as representative, and the KOH that its test result reflects the inventive example 4, example 5 and 0.025M equally makees mineralizer, the Bi of 200 ℃ of hydro-thermal reaction 15h
2S
3The luminescent properties of product; Whisker selects example 2 products as representative, and its test result reflects the luminescent properties of the inventive example 3 products equally.