Method for preparation of nanoparticles chalcogenide semiconductive materials

FIELD: chemistry.

SUBSTANCE: activation of chalcogen and dichalcogenide is implemented beforehand in alkali containing hydrazine-hydrate at temperature 70-80oC at ratio alkali/chalcogen equal to 2.3-2.5:1 for sulphur and selenium 6-8:1 for tellurium and at ratio alkali/dichalcogenide equal to equal to 2.5-3.0:1. Alkali is potassium or sodium hydroxide, organic dichalcogenide is compound of general formula R2Y2 whereat R - C6H5, C6H5CH2, C2H5, C4H9, HOCH2CH2, (HOCH2)2CH, CH2=CHCH2, C8H17. Nanoparticles are obtained by interreaction of metal salt with elemental chalcogen and in the meantime with organic dichalcogenide being the source of ligands - nanoparticles stabilisators at temperature 40-60oC. The resultant chalcogenide semicondactive nanoparticles have the general formula MenYm(YR)2(n-m) whereat Me - Zn, Cd, Hg, Y - S, Se, Te, n=10-30, m=8-24, R is organic radical.

EFFECT: simple nanoparticles obtaining and high yield of the product.

2 cl, 1 tbl

 

The invention relates to the field of nanotechnology and specifically relates to a method of producing nanoscale particles of chalcogenide materials, for example materials of the composition of the AIIBVIwhere AndII- the metal of subgroups of Zn, Cd or Hg), BIVthe chalcogen (S, Se, Te).

Connection type AndIIBVIalready more than half a century occupy an important place in the semiconductor electronics [1]. They are used to generate detectors, solar cells, semiconductor light sources, modulators, waveguides, laser Windows, the magnetic resistors, vidicons and other functional elements of the electronic devices [1, 2]. Research in the last 10-15 years has shown that when the characteristic size of the semiconductor particles less than 10 nm, many of their physico-chemical properties differ significantly from those of macroscopic objects [3]. Therefore, miniaturization of the functional elements of the chip to nanorana requires the use of new technologies, especially in semiconductor materials. Existing approaches in this direction are analyzed in the reviews [3, 4].

Most often for nanoparticles of semiconductor materials using chemical synthesis, primarily with the use of the processes of condensation from solutions. However, a generic approach for the ex connection types And IIBVIthis method does not exist. Thus, to obtain sulphide ZnS and CdS often use hydrogen sulfide [5]. Application for such purposes H2Se and especially N2Those due to their inaccessibility, toxicity, and volatility is very problematic. The use of aqueous solutions of Na2S (Na2Se and Na2Te) is faced with the difficulties of regulating the size of nanoparticles [6]. To this end, in the reaction system add thiols (n-octanethiol, thiophenol, benzylmercaptan and others) [4, 7]. However, the thiols are easily oxidized in the presence of air to disulfides [8], and selenay (RSeH) and to an even greater extent telaroli (RTeH) are extremely remote and extremely unstable compounds [9], their use for the stabilization of nanoparticles selenides and tellurides almost impossible and, apparently, still has not been applied.

To obtain nanosized semiconducting chalcogenide materials is promising use as raw materials of chalcogens in the elemental state. In this state, all three chalcogen available, stable during storage, practically non-toxic, have no smell, easily obtained in a sufficiently pure form.

However, the direct reaction of S, Se, or Te, for example, cadmium chloride is carried out only in hard conditions (heating in an autoclave for 24 cha is in the presence of Ethylenediamine as activator interface) [10].

Closest to the claimed method is a method for the synthesis of nanoparticles of ZnS and CdS (as well as PbS and MnS), based on the use of elemental sulfur and complexes of metal salts with oleylamine. The corresponding complexes are mixed with sulfur and heat, which leads to the formation of nanoparticles. Oleylamine in this case acts as an activator of sulfur and ligand-stabilizer [11] (prototype).

The disadvantages of the prototype include the following:

1. Oleylamine is difficult and quite expensive reagent.

2. Using this method, most likely you can only get sulfide nanoparticles as elemental selenium and especially tellurium almost not activated organic amines, even at low heat.

3. By heating elemental sulfur capable of reacting with a nitrogen-containing unsaturated compounds, which include oleylamine, as the double bond and the amino group [12], which can lead to uncontrolled pollution of the obtained particles.

We propose a method of producing nanoparticles chalcogenide semiconductor materials based on the interaction of the metal salt with elemental chalcogen (S, Se, Te) and simultaneously with organic dial-cogenitor (R2Y2Y is S, Se, Te; R=C6H5With6H5CH2With2H5With4H , (NON2)2CH, NON2CH2CH2=SNSN2C8H17), which is the source of ligands, and stabilizers. The synthesis of nanoparticles is carried out in a water-hydrazine powered environment at a temperature of 40-60°C With pre-activation of the chalcogen and organic dichalcogenide alkali in the hydrazine-hydrate.

The chemical method described by the following equations:

1). Activation of the chalcogen

2Y+MAN+Na2H4·H2O→2M2Y+N2+5H2O,

where M=Na, K; Y=S, Se, Te.

2). Activation of dichalcogenide

2R2Y2+4MOH+N2H4·H2O→4RYM+N2+5H2Oh,

where M=Na, K; Y=S, Se, Te; R=C6H5With6H5CH2C2H5With4H9, (NON2)2CH, NON2CH2CH2=SNSN2C8H17.

3). The synthesis of nanoparticles

pmech2+mM2Y+2(n-m)RYM→(MenYm)(YR)2(n-m)+2nMX,

where Me=Zn, Cd, Hg; X Is Cl, Br, 0,5SO4, NO3CH3Soo; n=10-30, m=8-24; M, Y, and R - see equations 1 and 2.

In a separate reaction vessels are activated chalcogen (reaction 1) and the corresponding organic dichalcogenide (reaction 2). Activation is carried out in the conditions described previously [13], the influence of alkali in the hydrazine-hydrate at a temperature of 70-80°C. the resulting solutions are combined and the mixture was added dropwise n and vigorous stirring to aqueous salt solution Fur 2at a temperature of 40-60°C.

The resulting nanoparticles (MenYm)(YR)2(n-m)separated by fractional crystallization, and by analogy with the work of [14] can be attributed to the following structure:

Evidence of the formation of nanoparticles can serve as the data of elemental analysis for carbon and hydrogen, as well as the solubility of the products obtained in some organic solvents such as dimethylsulfoxide, dimethylformamide, acetonitrile, and some derivatives in water. It is well known that the chalcogenides of zinc, cadmium and mercury, and many are known for their halogenate have a very low solubility in water. IR and Raman spectra of the MRP of the products obtained contain broadened signals, manifested in areas characterized for the presence of gangs R.

The proposed method for obtaining nanoparticles of chalcogenide materials has the following advantages:

1. The method is based on the available raw material: a simple metal salts, elemental chalcogen, affordable and sustainable (especially for sulfur and selenium) dichalcogenides, heavy product inorganic chemistry - hydrazine-hydrate, caustic potash or caustic soda.

2. The method is universal both in relation to the received chalcogenides (sulfides, selenides or tellurides), and against the Oia to the metal (Zn, Cd, Hg).

3. The method allows to obtain nanoparticles, stabilized by ligands of diverse structure, to which if necessary can be easily adjusted hydrophilic-hydrophobic balance, which can determine the solubility of the particles in different solvents.

4. By varying the ratio between the amount of metal salt, the chalcogen and ligand-stabilizer, you can change the size of the resulting nanoparticles and the dispersion stability of the corresponding systems.

5. As a source of ligand-stabilizer of nanoparticles offers organic dichalcogenides, the use of which is more convenient from the preparative point of view compared to thiols, phosphines and other ligands. Organic dichalcogenides can easily be obtained from the elemental chalcogens and organolanthanide in the system hydrazine-hydrate-based [13].

6. The nanoparticles are formed with yields close to quantitative (based on the metal used).

Salient features of the proposed method are the following:

1. The synthesis of nanoparticles performed with the use of elemental chalcogens that pre-activate the alkali in the hydrazine-hydrate.

2. The synthesis is carried out in the presence of ligands, and stabilizers, which receive pre-activation of organizedgaragesale R 2Y2the alkali in the hydrazine-hydrate.

3. The process of obtaining nanoparticles is carried out in odnoseriynogo environment at a temperature of 40-60°C.

Activation of chalcogens and organic dichalcogenides alkali in the hydrazine-hydrate-known and widely used in the synthesis halogenorganics compounds (e.g., [13]). However, in the proposed method, it is used in other capacities - first, chalcogen and organic dichalcogenides are used simultaneously, and secondly, they are activated for the synthesis of nanoparticles based on metal salts (zinc, cadmium, mercury). Only the aggregate impact of the chalcogen and dichalcogenide in activated forms allows you to get the desired result. Use only halogeno (without organic dichalcogenides) leads to the rapid formation of precipitation MeY, having a color that corresponds to the literature data, which are not available soluble in organic solvents. Apparently, the particles sediment in this case does not meet the nano.

Carrying out the reaction of synthesis of nanoparticles at temperatures below 40°C slows the reaction rate and complicates the selection of the nanoparticles. Raising the temperature above 60°C leads to the uncontrolled formation of larger particles chalcogenide.

The proposed method is illustrated by examples presented is in the table.

In the reaction flask to activate the chalcogen place necessary to activate the volume of alkali ratio (alkali:chalcogen = 2,3-2,5:1 to sulfur and selenium and 6.0 to 8.0:1 for tellurium provides preferential activation to anions Y2-and add hydrazine hydrate. In the resulting solution with vigorous stirring and the temperature of 70-80°C portions add the required amount of powdered sulfur (selenium or tellurium), after prisypanija the chalcogen the mixture is stirred at a temperature of 70-80°C for 1-2 hour. Lowering the temperature of the dissolution of the chalcogen below 70°C contributes to the partial formation of dichalcogenide (or even polyalkalene anions Yn2-), which leads to the final product (chalcogenide metal) non-uniform structure. The temperature of the dissolution of the chalcogen above 80°C is impractical, in particular, due to the additional energy consumption.

To another reaction flask alkali in an amount necessary to activate dichalcogenide R2Y2(the ratio of alkali:dichalcogenide = 2,5-3,0:1), and add hydrazinehydrate. To the resulting solution was added in several portions of dichalcogenide R2Y2at a temperature of 70-80°C. and stirred the reaction mixture at this temperature for 1-2 hours. The use of temperatures below 70°C is impractical due to the increase in the time of activation and incomplete conversion dichalcogenide. Increasing the temperature above 80°C has no significant positive effect, but requires additional energy consumption.

The obtained solutions chalcogenide alkali metal (M2Y) and halogenate (RYM) unite and under stirring at a temperature of 40-60°C pin to the aqueous solution of the corresponding salt of zinc, cadmium or mercury.

In examples 1-3, 10-14 (chart) product separates in the form of fine powder, which is soluble in highly polar organic solvents. From the obtained solutions product can be Presiden the effects of other solvents (ethanol, water and others). In examples 4-6, the target product is separated in the form of an emulsion, from which the fine powder falls under the action of ethanol. In other examples, the product is soluble in water and hydrazine powered solution and is in powder form under the action of ethanol.

The resulting products do not have characteristic melting points and change the color (darken) at temperatures above 150-200°C.

Thus, the proposed method allows to obtain a chalcogenide semiconductor nanoparticles simple formulations against method.

Sources of information

1. Physics and chemistry of compounds AndIIBVI./ Edited Saeideh. - M.: Mir. 1970.

2. Berchenko NN. and other Semiconductor solid is e solutions and their application.- M: Voenizdat. 1982. 208 S.

3. Khairutdinov Russia, having got Chemistry of semiconductor nanoparticles. // USP. 1998. T. No. 2. S.

4. S. p. Gubin, Kataeva N.A., Khomutov G.B. Promising areas of nanoscience: chemistry of nanoparticles of semiconductor materials. // Proceedings of the Academy of Sciences. The series of chemical. 2005. No. 4. S.

5. Li Y., Liao, H., and others // Inorg. Chem. 1999, V.38. P.1382.

6. Gautan U.K., Ghosh M, C.N.Rao // Chem. Phys. Lett. 2003. V.381. P.1.

7. Vossmeyer t and other Double-Layer Superlattice Structure Built Up of Cd32S14(SCH2CH(OH)CH3)364H2O Clusters. // J. Am. Chem. Soc. 1995. V.117. No. 51. P.12881.

8. Koval I. Thiols as synthons. // USP. 1993. T. No. 8. P.813.

9. General organic chemistry. Ed. Dbarton and Idillia. V.6.-M.: Chemistry. 1984. 544 C.

10. Deng Z.X., etc. // Inorg. Chem. 2003. V.42. R.

11. Joo J., and others // J. Chem. Soc. 2003. V.125. P.11100 (prototype).

12. Reactions of sulfur with organic compounds. Ed. Mgorshkova. - Novosibirsk: Science (Siberian branch). 1979. 367 C.

13. Deryagina E.N., Resavska NV and other Synthesis halogenorganics compounds in primary and recovery systems. "Izv. An. Ser. chem. 2005. No. 11. S.

14. Patolsky F. etc. // J. Am. Chem. Soc. 2003. V.125. P.13918.

1. Method for producing nanoparticles chalcogenide semiconductor materials of composition MenYm(YR)2(n-m)where Me is Zn, Cd, Hg, Y - S, Se, Te, n=10-30, m=8-24, R is an organic radical, including pre-activation organic dichalcogenide, which IP is the time ligands - stabilizers nanoparticles, and elemental chalcogen in alkali containing hydrazine hydrate and their interaction with the metal salt at a temperature of 40-60°C.

2. The method according to claim 1, characterized in that the activation of the chalcogen and dichalcogenide carried out at a temperature of 70-80°C at a ratio of alkali:the chalcogen, equal to 2.3-2.5:1 for sulfur and selenium and 6-8:1 tellurium, and when the ratio of alkali:dichalcogenide, equal to 2.5 to 3.0:1, the use of alkali hydroxide of potassium or sodium, and organic dichalcogenide use connections R2Y2where R6H5With6H5CH2With2H5With4H9, HOCH2CH2, (NON2)2CH, CH2=SNSN2C8H17.



 

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EFFECT: possibility for producing highly pure powder of platinum with small content of additives at lowered expenses.

5 cl, 1 ex

FIELD: powder metallurgy, namely production of metal containing nanoparticles.

SUBSTANCE: method comprises steps of interaction of aqueous solution of natural water-soluble arabin

galactan polysaccharide with concentration 1 - 50% as stabilizer and reducer of formed nanoparticles and aqueous solutions with content of metal salts 0.0067 -

2 mmol at presence of ammonium hydroxide or sodium hydroxide; soaking solution for 5 - 60 min at temperature 20 - 90°C; filtering it; precipitating formed filtrate into ethyl alcohol; separating it and drying deposit. It allows produce metal-containing nanoparticles with metal content in range 0.1 - 21.0%.

EFFECT: possibility for producing stable water-soluble metal containing structures, increased life period of nanoparticles.

4 cl, 7 ex

FIELD: production of submicron powders of pure metals and of metal compounds in bath with liquid.

SUBSTANCE: method for preparing liquid dispersion including metal-containing submicron particles comprises steps of creating bath with selected liquid in reactor; preparing mixture having metal- containing fluid capable at predetermined condition to be decomposed in selected liquid for forming metal-containing submicron particles; introducing prepared mixture to bath with selected liquid; providing in bath condition suitable for decomposition at least of some part of metal-containing liquid in selected liquid for forming metal-containing submicron particles dispersed in selected liquid. According to invention mixture including metal-containing fluid is added by bubbling into bath with selected liquid in the form of mixture formed by mixing metal-containing fluid with inert carrier gas.

EFFECT: possibility for realizing continuous process of improved economical effectiveness.

30 cl, 1 dwg, 3 ex

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