CN105692567A - Cu2FeSnSe4 powder material with kesterite structure and its liquid phase preparation method - Google Patents

Abstract

The invention discloses a kesterite structure Cu ₂ FeSnSe ₄ powder material for solar photovoltaic cells and a liquid phase preparation method thereof, comprising the following steps: raw materials CuCl ₂ 2H ₂ O, FeCl ₃ 6H ₂ O, SnCl ₄ . Weigh 5H ₂ O and selenium powder according to the molar ratio, put them into a round-bottomed three-necked flask and mix them, then add the organic solvent triethylenetetramine solution to obtain a uniform light blue solution; pass in nitrogen as a protective gas, and place at a constant temperature Heat to 200-230°C in an oil bath and keep it for 0.5-12 hours, then naturally cool to room temperature; wash the product with absolute ethanol and distilled water in sequence, then filter and dry to obtain a black powder. The liquid-phase preparation method of the kesterite structure Cu ₂ FeSnSe ₄ powder material is green and pollution-free, the reaction time is short, the required temperature is low, the operation is simple, and the cost is low, and it is suitable for the Cu ₂ FeSnSe ₄ powder material to be used in the industrialization of the absorbing layer of photovoltaic cells .

Description

Cu2FeSnSe4 powder material with kesterite structure and liquid phase preparation method thereof

technical field

The invention belongs to the technical field of materials for solar photovoltaic cells, and in particular relates to a kesterite structure Cu ₂ FeSnSe ₄ powder material and a liquid phase preparation method thereof. The kesterite structure Cu ₂ FeSnSe ₄ powder material is applied to Cu ₂ FeSnSe ₄ thin films Solar cell absorber.

Background technique

With the gradual depletion of non-renewable resources, the energy crisis and the ensuing environmental pollution are becoming more and more serious. As a clean renewable energy source, solar energy is non-toxic, harmless and non-polluting. It is the best solution for people to solve energy and environmental problems. good choice. In the process of industrialization today, photovoltaic modules have been widely used, and the process route is relatively mature. The main problems of current photovoltaic power generation are focused on improving the photoelectric conversion efficiency of solar cells and reducing production costs.

In view of the above problems, the second-generation thin-film solar cells have attracted widespread attention because of their low material cost, large single-chip area, high integration, and high photoelectric conversion efficiency. Since the development of thin-film solar cells, the relatively mature research is copper indium gallium selenide (Cu(In _x Ga _1-x )Se ₂ , abbreviated as CIGS) thin film with high photoelectric conversion efficiency and good stability. solar cell. However, CIGS thin-film solar cells have the problem of scarcity of indium (In) and gallium (Ga) elements, and have complex element ratios and multi-layer structures, which have strict requirements on process, equipment and technical difficulty, which limit CIGS thin-film solar cells. Industrialization of solar cells. In recent years, a kesterite-structured copper-iron-tin-selenide (Cu ₂ FeSnSe ₄ , abbreviated as CFTSe) powder has attracted widespread attention as a material for the absorber layer of thin-film solar cells. Similar to chalcopyrite-type CIGS crystal structure, high absorption coefficient (up to 10 ⁴ cm ^-1 ), has a direct band gap (~1.5eV) that closely matches the solar spectrum, does not cause pollution to the environment, and has low production costs . In addition, CFTSe uses the earth-abundant iron and tin to replace the rare indium and gallium in CIGS to further reduce the cost of solar cells, so it has a huge research space and is expected to replace CIGS thin film solar cell absorber materials.

So far, only a few literatures have studied the preparation of Cu ₂ FeSnSe ₄ nanocrystals, not to mention the use of Cu ₂ FeSnSe ₄ as the absorber material to make solar cells, so the current priority is to synthesize high-quality Cu ₂ FeSnSe ₄ nanocrystals. Therefore, the present invention proposes a method for preparing Cu ₂ FeSnSe ₄ nanocrystals that can be produced on a large scale, is environmentally friendly, and has low cost, which is of great significance to this field.

Contents of the invention

The technical problem to be solved by the present invention is to propose a new kesterite structure Cu ₂ FeSnSe ₄ powder material and its liquid phase preparation method, the liquid phase preparation method of the kesterite structure Cu ₂ FeSnSe ₄ powder material is green and pollution-free, The reaction time is short, the required temperature is low, the operation is simple and the cost is low, and it is suitable for large-scale production of Cu ₂ FeSnSe ₄ powder.

To achieve the above object, the technical solution of the present invention is as follows:

A liquid-phase preparation method of kesterite structure Cu ₂ FeSnSe ₄ powder is characterized in that, using an organic solvent as a carrier, the Cu ₂ FeSnSe ₄ powder is synthesized by a liquid-phase reflux method under normal pressure, comprising the following steps:

1) Weigh the raw materials CuCl ₂ 2H ₂ O, FeCl ₃ 6H ₂ O, SnCl ₄ 5H ₂ O, and selenium powder according to the molar ratio, put them into a round-bottomed three-necked flask, and then add the organic solvent triethylenetetramine solution , placed for 3-5 minutes to obtain a uniform light blue solution;

2) Pour nitrogen into the three-necked round-bottom flask above, place it in a constant temperature oil bath, heat it to 200-230°C, and keep it for 0.5-12 hours, then cool it down to room temperature naturally;

3) Finally, the cooled product was collected, washed with absolute ethanol and distilled water in sequence, then filtered and dried to obtain a black powder.

When weighing 2-8mmol CuCl ₂ 2H ₂ O, 1-4mmol FeCl ₃ 6H ₂ O, 1-4mmol SnCl ₄ 5H ₂ O, 4-16mmol selenium powder in step 1), the organic solvent added is triethylenetetramine Solution, the consumption of solution is 20-60ml.

The molar ratio of CuCl ₂ 2H ₂ O, FeCl ₃ 6H ₂ O, SnCl ₄ 5H ₂ O and selenium powder in step 1) is preferably 2: (1-1.5): (1-1.5): (4-5 ).

In step 3), the cooled product was finally collected, washed with absolute ethanol and distilled water for 3-5 times respectively, then filtered, and dried in a drying oven at 60-100°C for 2-10 hours to obtain a black powder.

The kesterite structure Cu ₂ FeSnSe ₄ powder material of the present invention is prepared by the above method.

Compared with prior art, the present invention has following advantage:

(1) The raw materials are all ordinary metal halides instead of expensive high-purity elemental powders, and do not contain any special salts such as ethyl xanthate, etc., and the cost is low;

(2) A new solvent, triethylenetetramine solution, has not been used to synthesize Cu ₂ FeSnSe ₄ powder by solution thermal method; compared with other amine solvents, this solvent not only has strong reduction and strong complexation Sex, low volatility and low toxicity, higher boiling point, better dispersibility to raw materials, and cheaper price;

(3) The reaction conditions in the whole experiment process are mild, and there is no need for high temperature, high pressure, vacuum and other conditions that are strictly required by the autoclave used in the traditional solvothermal method to prepare materials;

(4) The reaction time is short, the reaction temperature is low, the properties of the product are easy to control, the safety is high, the operation is simple, and it is suitable for large-scale industrial production.

Description of drawings

FIG. 1 is the XRD spectrum of the Cu ₂ FeSnSe ₄ sample synthesized in Example 1.

Figure 2 is the Raman spectrum of the Cu ₂ FeSnSe ₄ sample synthesized in Example 1 - because the XRD energy spectrum of Cu ₂ FeSnSe ₄ is similar to the XRD energy spectrum of Cu ₂ SnSe ₃ , Cu ₂ Se and CuSe , the Raman spectrum can illustrate that the product does not contain the above three powders.

FIG. 3 is the XRD spectrum of the Cu ₂ FeSnSe ₄ sample synthesized in Example 2.

detailed description

The following examples are intended to further illustrate the present invention, rather than limit the present invention.

Example 1:

Weigh 4mmol CuCl ₂ 2H ₂ O, 2mmol FeCl ₃ 6H ₂ O, 2mmol SnCl ₄ 5H ₂ O, 8mmol selenium powder, put them into a round-bottomed three-neck flask, add 30ml of triethylenetetramine, and place it for 3-5 minutes to obtain a uniform For the light blue solution, nitrogen was introduced as a protective gas, and stirred and condensed to reflux. The round-bottomed three-necked flask was heated to 230°C in a constant temperature oil bath, and kept for 4 hours, and then naturally cooled to room temperature. Wash with water, ethanol and deionized water for 5 times respectively, then filter and dry in a drying oven at 90°C for 2 hours to obtain a black solid.

Example 2:

Weigh 4mmol CuCl ₂ 2H ₂ O, 2mmol FeCl ₃ 6H ₂ O, 2mmol SnCl ₄ 5H ₂ O, 8mmol selenium powder, put them into a round-bottomed three-neck flask, add 30ml of triethylenetetramine, and place it for 3-5 minutes to obtain a uniform For the light blue solution, nitrogen was introduced as a protective gas, and stirred and condensed to reflux. The round-bottomed three-neck flask was heated to 200 ° C in a constant temperature oil bath, and kept for 2 hours, and then naturally cooled to room temperature. Wash with water, ethanol and ionic water three times respectively, then filter and dry in a drying oven at 60°C for 6 hours to obtain a black solid.

Claims (5)

1. a kesterite structure Cu ₂ FeSnSe ₄ liquid phase preparation method of powder material, it is characterized in that, take organic solvent as carrier, under normal pressure, synthesize Cu ₂ FeSnSe ₄ powder with liquid phase reflux method, comprise the following steps: 1) Weigh the raw materials CuCl ₂ 2H ₂ O, FeCl ₃ 6H ₂ O, SnCl ₄ 5H ₂ O, and selenium powder according to the molar ratio, put them into a round-bottomed three-necked flask, and then add the organic solvent triethylenetetramine solution , placed for 3-5 minutes to obtain a uniform light blue solution; 2) Pour nitrogen into the three-necked round-bottom flask above, place it in a constant temperature oil bath, heat it to 200-230°C, and keep it for 0.5-12 hours, then cool it down to room temperature naturally; 3) Finally, the cooled product was collected, washed with absolute ethanol and distilled water in sequence, then filtered and dried to obtain a black powder. 2. The liquid phase preparation method of kesterite structure Cu ₂ FeSnSe ₄ powder material according to claim 1, characterized in that, when weighing 2-8mmol CuCl ₂ ·2H ₂ O, 1-4mmolFeCl ₃ · 6H ₂ O, 1-4mmol SnCl ₄ ·5H ₂ O, 4-16mmol selenium powder, the amount of organic solvent triethylenetetramine solution is 20-60ml. 3. The liquid-phase preparation method of kesterite structure Cu ₂ FeSnSe ₄ powder material according to claim 1 or 2, characterized in that, in step 1), CuCl ₂ ·2H ₂ O, FeCl ₃ ·6H ₂ O, SnCl _4. The molar ratio of 5H ₂ O and selenium powder is 2: (1-1.5): (1-1.5): (4-5). 4. The liquid-phase preparation method of kesterite structure Cu ₂ FeSnSe ₄ powder material according to claim 1, characterized in that, in step 3), the cooled product is finally collected and washed successively with absolute ethanol and distilled water 3-5 times, then filter, place in a drying oven and dry at 60-100°C for 2-10 hours to obtain a black powder. 5. A kesterite structure Cu ₂ FeSnSe ₄ powder material, characterized in that it is prepared by the method described in any one of claims 1-4.