CN102674435A

CN102674435A - Solvothermal synthesis method for copper, zinc, tin and sulfur nanocrystals

Info

Publication number: CN102674435A
Application number: CN2012101441303A
Authority: CN
Inventors: 汪浩; 宗恺; 孙玉绣; 高志华; 刘晶冰; 朱满康; 严辉
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2012-05-10
Filing date: 2012-05-10
Publication date: 2012-09-19
Anticipated expiration: 2032-05-10
Also published as: CN102674435B

Abstract

The invention discloses a solvothermal synthesis method for copper, zinc, tin and sulfur nanocrystals, and belongs to the technical field of preparation of functional nanometer materials. According to the method, pyridine is used as a solvent at a low temperature, so that carbon and oxygen elements can be prevented from being introduced in the conventional copper, zinc, tin and sulfur nanocrystal synthesizing process. The method comprises the following steps of: weighing a certain amount of copper chloride, zinc chloride, tin chloride and thioacetamide in the molar ratio of 2:1:1:5; adding the copper chloride, the zinc chloride, the tin chloride and the thioacetamide into the pyridine, continuously stirring the solution, and putting the solution into an airtight reaction kettle after the solution is uniformly stirred; heating in a drying oven at the temperature of between 130 and 140 DEG C for 15 to 20 hours, and cooling to room temperature along with the temperature variation of a furnace; taking powder out, and sequentially centrifuging by using ethanol and distilled water; and drying in a vacuum drying oven, and thus obtaining the copper, zinc, tin and sulfur nanocrystals. The method has a simple process and a large-scale production potential, and is oxygen-free, low-carbon and low in cost.

Description

The solvent process for thermosynthesizing that a kind of copper-zinc-tin-sulfur is nanocrystalline

Technical field

The present invention relates to the nanocrystalline solvent process for thermosynthesizing of a kind of copper-zinc-tin-sulfur.In lower TR, use pyridine as solvent, can overcome in the past carbon in the nanocrystalline building-up process of copper-zinc-tin-sulfur, the introducing of oxygen element.The preparing technical field that belongs to the function nano material.

Background technology

At present, solar energy industryization is prevailing is monocrystaline silicon solar cell, non-crystal silicon solar cell and copper-indium-galliun-selenium (CuIn _1-xGa _xSe ₂, be called for short CIGS) and thin-film solar cells.But the crystal silicon solar energy battery cost is high, in answering popularization, is restricted; Amorphous silicon thin-film solar cell has serious photic efficient attenuating effect because the characteristic of material inherent metastable state and many defectives causes stability test lower, and the big area photoelectric transformation efficiency is difficult to further raising; CIGS has then used two kinds low abundance element In (0.049ppm) and Se (0.05ppm) in a large number.Especially rare elements In, the output of present annual In has only the 1200-1300 ton, and wherein half is used for the ito thin film that the plane shows industry, and the development space of leaving the CIGS battery for is very limited, so the development space of CIGS battery is very limited.

In recent years, new copper sulphur based material copper-zinc-tin-sulfur (Cu ₂ZnSnS ₄, be called for short CZTS) and noticeable.The CZTS of custerite structure is similar with the CIGS crystalline structure of yellow copper structure, and has higher photoabsorption coefficient (>10 ⁴Cm ^-1), about 1.50 eV of energy gap are complementary with the needed best energy gap of solar cell.And the element that is the higher and environmental protection of abundance that adopts of CZTS battery: Cu (50ppm), Zn (75ppm), Sn (2.2ppm), S (260ppm), thus can reduce production costs greatly, and wherein do not contain poisonous composition.But be expected to become the photoelectric functional material of the first-selected replaced C IGS of a new generation.

The solvent thermal building-up reactions is meant several kinds of components directly chemical combination or chemical reaction of taking place through intermediate state under the solvent thermal condition.But nanocrystalline preparation in early stage generally all is in polymer organic solvent (like oleyl amine, oleic acid etc.), to carry out, and the coating process in later stage also needs earlier nanocrystalline being dispersed in high molecular organic solvent and the organic binder bond to be mixed with ink.These macromolecule organics can not volatilize at low temperatures fully, and in the annealing heat treatment process (> 500 ℃, under the oxygen free condition), then be certain to take place carbonization phenomenon, inevitably have residual carbon in the film and exist.These residual carbons can form a large amount of defect states at the crystal boundary place, serve as the deathnium of electron hole, reduce carrier lifetime; The phase mutual diffusion of each element when perhaps hindering annealing suppresses the growth of CZTS crystal grain.And macromolecule organics such as oleic acid not only can be introduced carbon, have also inevitably introduced oxygen simultaneously, introduce the position that Sauerstoffatom not only can replace sulphur atom in the lattice in a large number, produce lattice distortion, and can generate a large amount of oxygen rooms.Effect with residual carbon is identical, and oxygen can serve as the deathnium of electron hole, reduces the life-span of current carrier greatly.This shows that the existence meeting of residual carbon and oxygen produces very adverse influence to the photoelectric transformation efficiency of entire device.

Summary of the invention

The objective of the invention is to deficiency, propose a kind of low-carbon (LC), the nanocrystalline compound method of the copper-zinc-tin-sulfur of anaerobic to prior art.In order to realize this purpose, the present invention adopts pyridine as reaction solvent, and the concrete operations step is following:

At first in the exsiccant beaker, add pyridine (80ml; 99%), is placed on the magnetic stirring apparatus and stirs, measure a certain amount of cupric chloride; Zinc chloride; Tin protochloride and thioacetamide (mol ratio: 2:1:1:5) slowly add pyridine solution successively, after stirring solution is moved in the autoclave, under 130-140 ℃ of condition, react 15h-20h; It is centrifugal successively with ethanol and zero(ppm) water to take out sample, and putting into after the vacuum drying oven drying taking-up afterwards, promptly to get copper-zinc-tin-sulfur nanocrystalline.

Usefulness of the present invention is: choose pyridine as solvent; Substitute macromolecule solvents such as oleyl amine commonly used, oleic acid; And highly toxic Hydrazine Hydrate 80 solvent, it is nanocrystalline to prepare controlled copper-zinc-tin-sulfur such as structure, composition, grain-size, dispersiveness, band gap width.Similar with Hydrazine Hydrate 80, pyridine has the good solubility ability to inorganic salt, but its toxicity is low, and can dissolve each other with alcohol, ether, the aqueous solution, can remove fully through washing.And it is little, the volatile low-carbon type organic solvent of anaerobic, molecular weight, and under lower temperature, (being lower than the annealing thermal treatment temp) just can be through volatilization removal fully.This method technology is simple, and the anaerobic low-carbon (LC) is with low cost, has the potentiality of scale operation.

Description of drawings

Fig. 1 is prepared nanocrystalline X-ray diffraction (XRD) collection of illustrative plates of copper-zinc-tin-sulfur of instance 1.

Fig. 2 is prepared nanocrystalline X-ray diffraction (XRD) collection of illustrative plates of copper-zinc-tin-sulfur of instance 2.

Fig. 3 is prepared nanocrystalline X-ray diffraction (XRD) collection of illustrative plates of copper-zinc-tin-sulfur of instance 3.

Fig. 4 is the prepared nanocrystalline ESEM of copper-zinc-tin-sulfur (SEM) photo of instance 2.

Fig. 5 is the prepared nanocrystalline uv-visible absorption spectra picture of copper-zinc-tin-sulfur of instance 2.

Embodiment

Below in conjunction with accompanying drawing and embodiment, further illustrate substantive distinguishing features of the present invention and remarkable advantage, the present invention only is confined to the embodiment that stated by no means.

In following examples, adopt the German Bruker Advance D-8 of company x-ray powder diffraction instrument (Cu K α radiation, λ=1.5406) to measure the structure of prepared powder; Adopt the microscopic appearance of the prepared powder of Hitachi S-3500N determination of electron microscopy; Adopt the UV2800 ultraviolet-visible pectrophotometer to measure the band gap of prepared powder.

Embodiment 1

1). measure the 80ml pyridine;

2) take by weighing cupric chloride, zinc chloride, tin protochloride and thioacetamide, wherein the quality of cupric chloride is 1.9396g, and copper, zinc, tin, sulphur mol ratio are 2:1:1:5;

3). under continuous agitation condition, add cupric chloride, continue stirred solution, treat to obtain the mazarine suspending liquid A after solute dissolves fully;

4). in suspending liquid A, add zinc chloride, continue to stir, treat to obtain light blue suspension-s B after solute dissolves fully;

5). in suspension-s B, add tin protochloride, continue to stir, obtain green aaerosol solution C, add thioacetamide afterwards again;

6). after stirring, solution is moved in the closed reactor; Be placed in 130 ℃ the baking oven and heat 15h, cool to room temperature afterwards with the furnace;

7). take out powder, centrifugal with ethanol, use zero(ppm) water centrifugal again; In vacuum drying oven, dry afterwards; It is nanocrystalline promptly to make copper-zinc-tin-sulfur.

XRD figure spectrum by Fig. 1 is visible, and the nanocrystalline characteristic peak of prepared copper-zinc-tin-sulfur is 28.5 °, and intensity is less, thereby the powder of explanation preparation is that the nanocrystalline crystallinity of copper-zinc-tin-sulfur is not good.

Embodiment 2

1). measure the 80ml pyridine;

2). take by weighing cupric chloride, zinc chloride, tin protochloride and thioacetamide, wherein the quality of cupric chloride is 1.9396g, and copper, zinc, tin, sulphur mol ratio are 2:1:1:5;

6). after stirring, solution is moved in the closed reactor; Be placed in 135 ℃ the baking oven and heat 15h, cool to room temperature afterwards with the furnace;

XRD figure spectrum by Fig. 2 is visible, and the nanocrystalline characteristic peak of prepared copper-zinc-tin-sulfur is 28.5 °, and intensity is bigger, and does not have the appearance of assorted peak, thereby the powder of explanation preparation is that copper-zinc-tin-sulfur is nanocrystalline and purity is higher.

And visible by Fig. 4, the prepared copper-zinc-tin-sulfur nano-crystalline granule particle diameter of instance 2 is between 10-20nm, and particle is tiny evenly.

Visible by Fig. 5, the instance 2 prepared pairing absorb light wavelength of copper-zinc-tin-sulfur nano-crystalline granule are 920nm, and the band gap of estimation sample is 1.34eV, approach the best band gap magnitude 1.5eV of solar cell.

Embodiment 3

1). measure the 80ml pyridine;

6). after stirring, solution is moved in the closed reactor; Be placed in 140 ℃ the baking oven and heat 15h, cool to room temperature afterwards with the furnace;

XRD figure spectrum by Fig. 3 is visible, and the nanocrystalline characteristic peak of prepared copper-zinc-tin-sulfur is 28.5 °.

Claims

1. solvent process for thermosynthesizing that copper-zinc-tin-sulfur is nanocrystalline is characterized in that step is following:

1). take by weighing cupric chloride, zinc chloride, tin protochloride and thioacetamide, its mol ratio is 2:1:1:5;

2). under continuous agitation condition, in pyridine, add cupric chloride, continue stirred solution, treat to obtain the mazarine suspending liquid A after solute dissolves fully;

3). in suspending liquid A, add zinc chloride, continue to stir, treat to obtain light blue suspension-s B after solute dissolves fully;

4). in suspension-s B, add tin protochloride, continue to stir, obtain green aaerosol solution C, add thioacetamide afterwards again;

5). after stirring, solution is moved in the closed reactor; Be placed in 130-140 ℃ the baking oven and heat 15h-20h, cool to room temperature afterwards with the furnace;

6). take out powder, use ethanol and zero(ppm) water centrifugal successively; In vacuum drying oven, dry afterwards; It is nanocrystalline promptly to make copper-zinc-tin-sulfur.

2. the nanocrystalline solvent process for thermosynthesizing of a kind of copper-zinc-tin-sulfur according to claim 1 heats in 140 ℃ baking oven in the step 5) and does 15h.