CN114188442B - A preparation method of antimony-doped electrochemical deposition copper-zinc-tin-sulfur solar cell absorber layer - Google Patents

Abstract

The invention discloses a preparation method of an antimony doped electrochemical deposition copper zinc tin sulfur solar cell absorption layer, which is characterized by comprising the following steps: dissolving chemical reagents such as copper sulfate, zinc sulfate, stannous sulfate, sodium thiosulfate, sodium citrate, potassium tartrate and the like in deionized water solution according to a certain molar ratio; then, a quaternary copper zinc tin sulfur prefabricated layer is deposited on the metal molybdenum back electrode in an electrochemical mode; then, carrying out sulfuration annealing on the prefabricated layer and antimony source powder; finally, the material of the absorbing layer of the antimony doped electrochemical deposition copper zinc tin sulfur thin film solar cell is obtained. Compared with the prior art, the method has the advantages of greatly improving the photoelectric performance, and the like, well solves the technical problem of doping the solar absorbing layer of the electrochemical deposition copper zinc tin sulfur film, can accurately control the antimony element in the copper zinc tin sulfur film by regulating and controlling the amount of the antimony source in the vulcanization annealing process, has simple preparation process, good repeatability and low cost, and has good research and popularization and utilization values.

Description

A preparation method of antimony-doped electrochemical deposition copper-zinc-tin-sulfur solar cell absorber layer

technical field

The invention relates to the technical field of semiconductor materials and solar energy, in particular to a method for preparing an absorbing layer of an antimony-doped electrochemically deposited copper-zinc-tin-sulfur solar cell.

Background technique

Global economic development and population growth are jointly driving huge energy demands. Traditional resources such as oil, natural gas, and coal are becoming increasingly depleted. At the same time, the gas emitted from the combustion of fossil energy causes environmental pollution and complex climate changes. Human beings are facing the dual challenges of energy shortage and global warming. As one of the important forms of renewable energy utilization, solar photovoltaic power generation has very significant advantages. Its power generation resources are abundant, inexhaustible, clean and environmentally friendly, no fuel, no noise, no emissions, stable performance, long life, simple operation and maintenance, and the use of reliable renewable energy is an important material basis for social development.

In search of cheap, green, and stable semiconductor absorber materials, copper-zinc-tin-sulfur quaternary semiconductor materials have attracted more and more attention from scientists around the world. Because the material contains abundant, low-cost, non-toxic elements, and its band gap is very close to the optimal band gap of the single-junction solar cell absorber layer, it has become one of the most promising photovoltaic absorber materials. After continuous efforts in recent years, the highest photoelectric conversion efficiencies of pure copper zinc tin sulfur, pure copper zinc tin selenide and sulfur selenium mixed copper zinc tin sulfur selenium thin film solar cells have reached 11%, 11.6% and 12.6%, respectively, which shows that copper zinc tin sulfur thin film solar cells have great application prospects in the photovoltaic field.

At present, the main problem of the CuZnSnS system is the very low open circuit voltage, which is closely related to the structural disorder, which manifests as band tails and deep trap states. Among them, the copper-zinc antisite acceptor defect is the main factor leading to the band-tail defect, and the disorder of the tin element produces deep-level defects in the band gap. These defects constrain the performance of CuZnSnS solar cell devices, but the extent to which they affect the open circuit voltage is poorly understood. Dopants such as sodium, potassium, silver, antimony, cadmium, and germanium are introduced into the prefabricated film, and post-sulfurization or selenization annealing helps the crystallization of the copper-zinc-tin-sulfur film, reduces the disorder of metal elements, and is conducive to further improving the battery conversion efficiency.

Compared with other preparation methods, the theory of electrochemical deposition technology is perfect, the technology is more mature, and it is an industrialized large-scale production technology suitable for the preparation of metal thin film materials. To achieve electrodeposited multi-element thin films, the standard potential difference between the elements needs to be within 0.2 V. However, the standard potential differences of the four elements of copper, zinc, tin, and sulfur are relatively large, especially the standard potentials of zinc and copper are -0.76 V and +0.342 V, respectively, so there are technical difficulties in co-depositing copper-zinc-tin-sulfur thin films. Therefore, compared with other processes, there are technical difficulties in the electrochemical deposition of copper-zinc-tin-sulfur thin films. In order to improve the conversion efficiency of copper-zinc-tin-sulfur solar cells, how to do trace element doping on the absorber layer of electrochemically deposited copper-zinc-tin-sulfur thin film solar cells. So far, there is no relevant literature report on the electrochemical deposition of CuZnSnS thin film doping.

Contents of the invention

The object of the present invention is to provide a method for preparing an antimony-doped electrochemical deposition copper-zinc-tin-sulfur solar cell absorbing layer for the deficiencies of the prior art. The method of electrochemically depositing a quaternary copper-zinc-tin-sulfur prefabricated layer on the metal molybdenum back electrode is used, and the prefabricated layer and the antimony source powder are subjected to sulfidation annealing. The technical problem of depositing copper-zinc-tin-sulfur thin film solar energy absorbing layer is difficult, the preparation process is simple, the repeatability is good, the cost is low, and it has good research and popularization and utilization value.

The object of the present invention is achieved like this: a kind of antimony-doped electrochemical deposition copper-zinc-tin-sulfur solar cell absorption layer preparation method is characterized in that the preparation of antimony-doped electrochemical deposition copper-zinc-tin-sulfur thin-film solar cell absorption layer specifically comprises the following steps:

(1) Preparation of copper-zinc-tin-sulfur prefabricated layer

Chemical reagents such as copper sulfate, zinc sulfate, stannous sulfate, sodium thiosulfate, sodium citrate and potassium tartrate are mixed in a certain molar ratio, and then dissolved in a deionized aqueous solution to obtain an electrochemical deposition plating solution; the metal molybdenum back electrode is used as the working electrode, the silver-silver chloride is used as the reference electrode, and the platinum sheet is used as the counter electrode.

(2) Preparation of the absorbing layer

Putting the copper-zinc-tin-sulfur prefabricated layer obtained in step (1) under vacuum conditions containing antimony source powder for sulfidation annealing to obtain an antimony-doped copper-zinc-tin-sulfur thin film solar cell material, that is, an antimony-doped copper-zinc-tin-sulfur absorbing layer film.

The metal molybdenum back electrode is ultrasonically cleaned with alkaline solution, acetone, ethanol and deionized water for 5 to 30 minutes in sequence, then blown dry with nitrogen, and placed in a vacuum oven for standby.

The molar concentration ratio of the copper sulfate, zinc sulfate, tin sulfate, sodium thiosulfate, sodium citrate and potassium tartrate is 1-5:2-50:1-3:1-20:10-100:5-40.

The deposition temperature is 25°C, the deposition potential is -0.5--1.5 V (vs. Ag/AgCl), and the deposition time is 5-60 minutes.

The vulcanization degradation is specifically as follows: first place the electrochemically deposited copper-zinc-tin-sulfur prefabricated layer and a certain amount of antimony source powder in a graphite boat, then place the graphite boat in an annealing furnace, and then pass in an inert gas after vacuuming, set the initial temperature of vulcanization to 20-25°C, heat the annealing furnace at a heating rate of 5-80°C/S, end the temperature at 450-650°C, keep it warm for 10-60 minutes, and then naturally cool to room temperature.

The film thickness of the antimony-doped copper-zinc-tin-sulfur absorbing layer is 0.5-3 μm.

Compared with the prior art, the present invention has the advantages of effective doping of copper-zinc-tin-sulfur thin film, simple preparation process, controllable components, and good film crystallinity, which greatly improves the photoelectric performance of copper-zinc-tin-sulfur thin film solar cells, effectively solves the technical problem of doping the solar absorbing layer of electrochemically deposited copper-zinc-tin-sulfur thin film, has good repeatability, low cost, and has good research, popularization and utilization value.

Description of drawings

Fig. 1 is the SEM figure of the electrochemically deposited copper-zinc-tin-sulfur prefabricated layer prepared in embodiment 1;)

Fig. 2 is the XRD pattern of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 1;

Fig. 3 is the Raman diagram of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 1;

Fig. 4 is the SEM figure of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 1;

Fig. 5 is the SEM picture of the electrochemically deposited copper-zinc-tin-sulfur prefabricated layer prepared by embodiment 2;

Fig. 6 is the XRD pattern of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 2;

Fig. 7 is the Raman diagram of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 2;

Fig. 8 is the SEM figure of the antimony-doped electrochemically deposited copper-zinc-tin-sulfur film prepared in embodiment 2;

FIG. 9 is a J-V diagram of the antimony-doped electrochemically deposited copper-zinc-tin solar cell prepared in Example 2. FIG.

Detailed ways

The embodiment of the present invention provides a method for preparing an antimony-doped electrochemically deposited copper-zinc-tin-sulfur thin film solar cell absorber layer, which is used to solve the existing technical problem of difficult doping of the electrochemically deposited copper-zinc-tin-sulfur thin film. In order to better understand the present invention, the present invention will be further described in detail, and the protection content of the present invention is not limited only to the following examples.

Example 1

1) Clean the metal molybdenum back electrode sequentially with alkaline solution, acetone, ethanol and deionized water for 10 minutes, then blow dry with nitrogen, and put it in a vacuum drying oven for later use.

2) Weigh copper sulfate, zinc sulfate, tin sulfate, sodium thiosulfate, sodium citrate, and potassium tartrate in a molar ratio of 2:10:1:4:50:10, and dissolve them in 200 ml of deionized water solvent in turn to obtain the electrolyte to be plated; use the metal molybdenum back electrode cleaned in step 1) as the working electrode, the platinum sheet as the counter electrode, and the silver-silver chloride as the reference electrode. At 25°C, a copper-zinc-tin-sulfur prefabricated film was obtained.

Referring to accompanying drawing 1, scanning electron microscopy is used to characterize the copper-zinc-tin-sulfur prefabricated layer film prepared above, which shows that the surface of the prefabricated layer is smooth, dense and uniform in nanometer size.

3) Put step 2) the electrochemically deposited copper-zinc-tin-sulfur prefabricated layer and 0.2 g of antimony sulfide powder in a graphite boat, then place the graphite boat in an annealing furnace, pump high-purity nitrogen gas after vacuuming, set the initial temperature of vulcanization to 25°C, heat the annealing furnace at a heating rate of 50°C/S, and end the temperature at 550°C.

Referring to Figures 2 to 3, the copper-zinc-tin-sulfur absorbing layer prepared above is characterized by XRD and Raman spectroscopy. It can be seen that the peaks at 2q=18.21, 28.53, 32.98, 47.33 and 56.18° correspond to (101), (112), (200), (220) and (312) of kesterite-structured copper-zinc-tin-sulfur [JCPDS 26-0575], respectively. The diffraction peaks of the crystal plane do not appear the XRD diffraction peaks and Raman spectrum characteristic peaks of antimony and antimony-related compounds, indicating that the prepared film is a pure-phase copper-zinc-tin-sulfur film, and the antimony element has been doped into the electrochemically deposited copper-zinc-tin-sulfur film.

Referring to accompanying drawing 4, scanning electron microscopy was used to characterize the above-prepared copper-zinc-tin-sulfur absorbing layer film, which showed that the prepared antimony-doped copper-zinc-tin-sulfur absorbing layer film had a smooth surface, compact surface, fewer grain boundaries and good crystallinity.

Example 2

1) Clean the metal molybdenum back electrode sequentially with alkaline solution, acetone, ethanol and deionized water for 10 minutes, then blow dry with nitrogen, and put it in a vacuum drying oven for later use.

2) Weigh copper sulfate, zinc sulfate, tin sulfate, sodium citrate, sodium thiosulfate and potassium tartrate in a molar ratio of 1:20:1:4:50:10, and dissolve them in 200 ml deionized water solvent in turn to obtain the electrolyte to be plated; the metal molybdenum back electrode cleaned in step 1) is used as the working electrode, the platinum sheet is used as the counter electrode, and the silver-silver chloride is used as the reference electrode. At 25°C, a copper-zinc-tin-sulfur prefabricated film was obtained.

Referring to Figure 5, scanning electron microscopy was used to characterize the copper-zinc-tin-sulfur prefabricated layer film prepared above, showing that the surface of the prefabricated layer is smooth, dense and uniform in nanometer size.

3) Put the electrochemically deposited copper-zinc-tin-sulfur prefabricated layer prepared in step 2) and 0.5 g of antimony sulfide powder in a graphite boat, then place the graphite boat in an annealing furnace, pump it into a high-purity argon gas, set the initial temperature of the vulcanization temperature to 25°C, heat the annealing furnace at a heating rate of 50°C/S, and set the termination temperature to 550°C.

Referring to accompanying drawings 6 to 7, the copper-zinc-tin-sulfur absorbing layer prepared above is characterized by XRD and Raman spectroscopy. It can be seen that the peaks at 2q=18.21, 28.53, 32.98, 47.33 and 56.18° correspond to (101), (112), (200), (220) and (312) of kesterite-structured copper-zinc-tin-sulfur [JCPDS 26-0575], respectively. The diffraction peaks of the crystal plane did not appear the XRD diffraction peaks and Raman spectrum characteristic peaks of antimony and antimony-related compounds, indicating that the prepared film was a pure-phase copper-zinc-tin-sulfur film, and antimony elements had been doped into the electrochemically deposited copper-zinc-tin-sulfur film.

Referring to accompanying drawing 8, scanning electron microscopy was used to characterize the copper-zinc-tin-sulfur absorbing layer film prepared above, which showed that the prepared antimony-doped copper-zinc-tin-sulfur absorbing layer film had smooth surface, compact surface, few grain boundaries and good crystallinity.

In other embodiments of the present invention, 1.0g, 1.5g, 2.0g or 2.5g of antimony sulfide powder is placed in the graphite boat respectively, and other operations are the same as in Example 2, and the obtained sample antimony-doped copper-zinc-tin-sulfur absorbing layer film is identical to the product of Example 2.

It can be seen from the above-mentioned Examples 1-2 that the XRD FWHM of the copper-zinc-tin-sulfur thin film grown in a graphite boat with 0.5 g of antimony sulfide powder is small, and its crystallinity is relatively high. The XRD half-maximum width of copper-zinc-tin-sulfur thin films grown with 0.2g antimony sulfide powder in graphite boats is relatively large, and the grain size of copper-zinc-tin-sulfur thin films is relatively small.

Referring to accompanying drawing 9, the comparison chart of the JV curves of the antimony-doped copper-zinc-tin-sulfur thin-film solar cell and the undoped copper-zinc-tin-sulfur thin-film solar cell prepared in Example 2 shows that the incorporation of antimony into the electrochemically deposited copper-zinc-tin-sulfur absorber layer significantly improves the electrical properties of the copper-zinc-tin-sulfur thin-film solar cell, the current density increases from 19.65mA/ ^cm2 to 21.34mA/ ^cm2 , the open circuit voltage increases from 0.6723 V to 0.710 V, and the fill factor increases from 61.7% increased to 64.3%, and the conversion efficiency increased from 8.15% to 9.76%.

By adjusting the content of the antimony source powder, the present invention can precisely control the composition of antimony-doped electrochemically deposited copper-zinc-tin-sulfur, thereby obtaining a solar cell device with high crystal quality and good morphology, antimony-doped electrochemically deposited copper-zinc-tin-sulfur-selenide thin film and a conversion efficiency close to 10%. The above is only a preferred embodiment of the present invention, and it should be pointed out that for anyone skilled in the art, without departing from the scope of the technical solution of the present invention, some improvements and modifications can also be made by the technology of the present invention, and these improvements and modifications should also be considered as protection scope of the present invention.

Claims (3)

1. A preparation method of an antimony doped electrochemical deposition copper zinc tin sulfur solar cell absorption layer is characterized in that a method for electrochemical deposition of a quaternary copper zinc tin sulfur prefabricated layer on a metal molybdenum back electrode is adopted, the prefabricated layer and antimony source powder are subjected to sulfuration annealing, and the antimony doped electrochemical deposition copper zinc tin sulfur thin film solar cell absorption layer is obtained, and the preparation method specifically comprises the following steps:

preparation of (one) prefabricated layer

Copper sulfate, zinc sulfate, stannous sulfate, sodium thiosulfate, sodium citrate and potassium tartrate are mixed according to the proportion of 1-5: 2-50: 1-3: 1-20: 10-100: 5-40 mol ratio of the mixed solution to deionized water to obtain an electrochemical deposition electroplating solution; a metal molybdenum back electrode is used as a working electrode, silver-silver chloride is used as a reference electrode, a platinum sheet is used as a counter electrode, a three-electrode constant potential method is used for depositing a quaternary copper zinc tin sulfide prefabricated layer, the deposition temperature is 20-30 ℃, the deposition potential is-0.5 to-1.5V, and the deposition time is 5-60 minutes;

(2) Preparation of the absorbent layer

The prepared copper zinc tin sulfur prefabricated layer is placed under vacuum condition containing an antimony source and a sulfur source for vulcanization annealing, and an antimony doped copper zinc tin sulfur absorbing layer with the film thickness of 0.5-3 mu m, namely an antimony doped copper zinc tin sulfur film solar cell material is prepared, wherein the antimony source is one or a mixture of more than two of antimony selenide powder, antimony sulfide powder and antimony selenide powder; the sulfur source is sulfur powder or hydrogen sulfide.

2. The method for preparing the antimony doped electrochemical deposition copper zinc tin sulfur solar cell absorption layer is characterized in that the vulcanization annealing is to place a copper zinc tin sulfur prefabricated layer, an antimony source and a sulfur source in a graphite boat of an annealing furnace, vacuum pumping is carried out, the amount of the antimony source is regulated and controlled, and then antimony elements in a copper zinc tin sulfur film can be precisely controlled, so that the antimony doped electrochemical deposition copper zinc tin sulfur film solar cell absorption layer material is obtained, the initial vulcanization temperature is 20-25 ℃, the temperature is heated to 450-650 ℃ at the temperature rising rate of 5-80 ℃/S, and the material is naturally cooled to room temperature after heat preservation for 10-50 minutes.

3. The method for preparing an absorber layer of an antimony doped electrochemically deposited copper zinc tin sulfide solar cell according to claim 1 or claim 2, wherein the sulfide annealed shielding gas is high purity nitrogen or argon.