CN110299451B - Flexible perovskite-copper indium gallium selenide laminated solar cell and preparation method thereof - Google Patents

Abstract

The invention discloses a flexible perovskite-copper indium gallium selenide laminated solar cell, which includes a flexible copper indium gallium selenide cell as a bottom cell unit and a perovskite cell as a top cell unit, the top cell unit and the bottom cell The cells are connected through an ITO interlayer. In the tandem solar cell of the present invention, two matching materials, CIGS and perovskite, are selected as the light absorption layer, and ITO with high conductivity and high light transmittance is selected as the intermediate layer tunnel junction, and the two sub-cells are integrated. Combined, the total amount of light reaching the bottom cell is increased, the series resistance is reduced, and the light absorption utilization rate is better than that of the single-junction cell; the present invention also selects the hole layer PTAA that is more compatible with the ITO intermediate layer and has high conductivity. And the PCBM electronic layer with hydrophobicity can further improve the efficiency and stability of the laminated battery.

Description

A flexible perovskite-copper indium gallium selenide tandem solar cell and its preparation method

technical field

The invention relates to a flexible perovskite-copper indium gallium selenium stacked solar cell and a preparation method thereof, belonging to the field of solar cell preparation technology and devices.

Background technique

In today's society, environmental pollution and non-renewable resource consumption caused by the extensive use of fossil energy represented by coal, oil and natural gas have become a major problem facing the sustainable development of mankind. Therefore, the development and use of new environmentally friendly and renewable new energy sources is the general trend of social development, and the preparation and use of solar cells have recognized advantages.

Perovskite light-absorbing layer materials are rich in sources and low in price. In recent years, the use of perovskite solar cells with a structure similar to dye-sensitized structures has attracted widespread attention in the photovoltaic industry. The photoelectric conversion efficiency of perovskite solar cells has improved very rapidly. The initial conversion efficiency in 2009 was only 3.8%, and it quickly increased to 10.9% in 2012. Today, perovskite solar cells have an efficiency of 23.7%.

However, the energy distribution in the sunlight spectrum is wide, and any existing semiconductor material can only absorb photons with energy higher than its energy gap value. The photons with lower energy in sunlight will pass through the battery, be absorbed by the back electrode metal, and be converted into heat energy; the excess energy of high-energy photons exceeding the energy gap width will be transferred to the battery material itself through the energy pyrolysis of photogenerated carriers. The lattice atoms heat the material itself. None of these energies can be transferred to the load through photogenerated carriers and become effective electrical energy. For better and more comprehensive absorption of light, tandem solar cells are born from this. The solar spectrum can be divided into several continuous parts, and the battery is made of the material with the best matching energy band width and these parts, and superimposed from the outside to the inside according to the order of the energy gap from large to small, so that the light with the shortest wavelength Utilized by the outermost wide-gap material cell, light with a longer wavelength can be transmitted in to be used by the narrower-gap material cell, which makes it possible to convert light energy into electrical energy to the greatest extent. Such a cell structure is a tandem solar cell , which can greatly improve performance and stability.

The current matching of the top and bottom cells in a tandem solar cell is a key factor affecting its performance. Therefore, the principle of structural design of a tandem solar cell is to make the absorption spectrum distribution of each single-junction cell reasonable. It is of great research significance to reasonably select the material and thickness of the absorber layer of the top layer and the bottom cell to solve the current matching of the tandem solar cell and make it have better performance.

Contents of the invention

Aiming at the key problems in the preparation of tandem solar cells, the present invention discloses a flexible perovskite-copper indium gallium selenium tandem solar cell and its preparation method. The technical problem to be solved is to use Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite thin film and CIGS thin film with two different band gaps and thicknesses of absorbing layers to achieve current matching between the top and bottom cells, and by optimizing the arrangement of energy levels at all levels, a highly efficient and stable tandem solar cell is prepared.

The present invention adopts following technical scheme for realizing the purpose of the invention:

A flexible perovskite-copper indium gallium selenide stacked solar cell is characterized in that it includes a flexible copper indium gallium selenide cell as a bottom cell unit and a perovskite cell as a top cell unit, the top cell unit and the The bottom battery cells are connected through the ITO intermediate layer;

The structure of the flexible copper indium gallium selenide battery is as follows from bottom to top: flexible stainless steel substrate, Mo metal electrode layer, CIGS light absorbing layer film, CdS buffer layer and AZO film;

The structure of the perovskite battery is as follows from bottom to top: PTAA hole transport layer, _{Cs 0.1} MA _0.9 PbI 2.9 Cl _0.1 perovskite light absorbing layer film, PCBM electron transport layer, C ₆₀ interface modification layer, Ag top electrode .

Further: in the flexible copper indium gallium selenide battery, the thickness of the flexible stainless steel substrate is 20-40 μm, the thickness of the Mo metal electrode layer is 400-600 nm, and the thickness of the CIGS light-absorbing layer film is 1-2 μm, the thickness of the CdS buffer layer is 400-600nm, the thickness of the AZO film is 200-300nm; in the perovskite battery, the thickness of the PTAA hole transport layer is 100-120nm, The thickness of the Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite light-absorbing layer film is 500-600 nm, the thickness of the PCBM electron transport layer is 30-40 nm, and the thickness of the C ₆₀ interface modification layer is 10-20 nm , the thickness of the Ag top electrode is 100-150nm; the thickness of the ITO middle layer is 30-50nm.

The preparation method of the flexible perovskite-copper indium gallium selenide laminated solar cell comprises the following steps:

(1) Preparation of flexible copper indium gallium selenide battery as the bottom battery unit

First, a layer of Mo metal electrode is sputtered on a flexible stainless steel substrate, and then a CIGS absorbing layer film is deposited by multi-component co-evaporation method, and then a CdS buffer layer is prepared by chemical water bath deposition method, and then a layer of AZO film is sputtered;

(2) Preparation of the middle layer

Sputtering an ITO intermediate layer on the AZO thin film of the flexible copper indium gallium selenide battery;

(3) Preparation of perovskite battery as top cell unit

(31) Utilize double-sided tape to paste the base on the glass; 6-10 mg of PTAA powder is dissolved in 1 mL of chlorobenzene, and then spin-coated onto the ITO intermediate layer to form a PTAA hole transport layer;

(32) Dissolve 0.645g PbI _powder and 0.024g CsCl powder in 1mL of a mixed solution made of DMF and DMSO at a volume ratio of 7:3, stir evenly to form a precursor solution; place the precursor solution in the The PTAA hole transport layer was spin-coated to form a film, and then the substrate was transferred to a tube furnace, and 3g MAI powder was placed in the tube furnace, and Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite was obtained by in-situ chemical vapor deposition Mineral light absorbing layer film;

(33) Dissolve 20-30 mg of PCBM powder in 1 mL of chlorobenzene, and then spin-coat it on the perovskite light-absorbing layer film to form a PCBM electron transport layer; thermally evaporate a layer of C on the PCBM electron transport layer. ₆₀ as the interface modification layer; finally evaporated Ag as the top electrode to obtain a flexible perovskite-copper indium gallium selenide tandem solar cell.

Further, the steps of the chemical water bath deposition method described in step (1) are: first add 100mL deionized water to the beaker, weigh 0.0549g cadmium chloride and 1.1418g thiourea and add it, then add 26mL mass concentration of 25 ~28% ammonia water, and finally add deionized water to make up to 200mL to obtain the buffer layer precursor; raise the temperature of the water bath to 60°C, soak the substrate in the buffer layer precursor for 20min, take it out and rinse it with deionized water The surface is blown dry with nitrogen to form a CdS buffer layer.

Further, in step (31), the PTAA is spin-coated at a speed of 2500-3000 rpm for 30-40 s, followed by annealing at 90° C. for 5 min.

Further, in step (32), the stirring temperature for forming the precursor solution is 70-90°C.

Further, in step (32), the precursor solution is spin-coated at a speed of 4000-5000 rpm for 30-40 s, followed by annealing at 100° C. for 30 min.

Further, in step (32), the conditions for the in-situ chemical vapor deposition are: firstly evacuate to 1-100 Pa, then raise the temperature to 140-150°C, keep the reaction for 60 minutes, and finally cool down to room temperature naturally, and take it out.

Further, in step (33), the spin-coating speed of forming the PCBM electron transport layer is 3000-4000rpm for 30-40s, followed by annealing at 60°C for 3min. The materials used in this experiment can be scaled up or down according to the specific implementation.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. In the tandem solar cell of the present invention, CIGS and perovskite are selected as the light-absorbing layer, and ITO with high conductivity and high light transmittance is selected as the intermediate layer tunnel junction, and the two sub-cells are The integrated combination increases the total amount of light reaching the bottom cell, reduces series resistance, and has better light absorption utilization than single-junction cells. The present invention also selects the hole layer PTAA that is more compatible with the ITO intermediate layer and has high conductivity, and the PCBM electron layer with hydrophobicity, which can further improve the efficiency and stability of the laminated battery.

2. The laminated solar cell of the present invention adopts a flexible substrate, which is light in weight, thin in thickness, good in flexibility, moderately bendable, excellent in performance, and widely used, which greatly facilitates the application of outdoor solar charging.

3. The stacked solar cell of the present invention has a simple preparation process, no expensive equipment application and cumbersome glove box operation, and can be prepared in the atmosphere, with strong processability.

4. The tandem solar cell of the present invention is easy to scale up due to its stack design, and can be appropriately expanded to the preparation of perovskite-perovskite, perovskite-silicon and other stacked cells.

Description of drawings

Fig. 1 is the structural representation of flexible copper indium gallium selenium solar cell in comparative example 1;

Fig. 2 is the current density-voltage (J-V) characteristic curve of flexible copper indium gallium selenide solar cell in comparative example 1;

3 is a schematic structural view of a flexible perovskite-copper indium gallium selenide tandem solar cell in Example 1;

Fig. 4 is the scanning electron micrograph of ITO intermediate layer in embodiment 1;

Fig. 5 is the scanning electron micrograph of Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite light absorbing layer film in embodiment 1;

FIG. 6 is a current density-voltage (J-V) characteristic curve of the flexible perovskite-CIGS tandem solar cell in Example 1. FIG.

Detailed ways

In order to make the above objects, features and advantages of the present invention more obvious and comprehensible, specific implementations of the present invention will be described in detail below in conjunction with examples. The following content is only an example and description of the concept of the present invention. Those skilled in the art make various modifications or supplements to the described specific embodiments or replace them in similar ways, as long as they do not deviate from the concept of the invention Or beyond the scope defined in the claims, all should belong to the protection scope of the present invention.

Comparative example 1

In this example, a flexible copper indium gallium selenide battery is used as a comparison. As shown in Figure 1, its structure from bottom to top is as follows: a flexible stainless steel substrate with a thickness of 30 μm, a Mo metal electrode layer with a thickness of 500 nm, and a CIGS light absorption layer with a thickness of 1 μm. thin film, 60nm thick CdS buffer layer, 300nm thick AZO thin film and 100nm thick Ag top electrode.

The preparation method of the flexible copper indium gallium selenide battery in this embodiment is as follows:

First, a layer of Mo metal electrode was sputtered on a flexible stainless steel substrate.

Then use the multi-stage co-evaporation method to deposit the CIGS absorbing layer film. For the specific method, please refer to the literature: Prog.Photovolt:Res.Appl.2008; 16:235-239.

The CdS buffer layer was prepared by chemical water-bath deposition method: firstly, 100 mL of deionized water was added to the beaker, 0.0549 g of cadmium chloride and 1.1418 g of thiourea were weighed, and then 26 mL of ammonia water with a mass concentration of 25-28% was added. Finally, add deionized water to make the volume to 200mL to obtain the buffer layer precursor; raise the temperature of the water bath to 60°C, soak the substrate in the buffer layer precursor for 20min, rinse the surface with deionized water after taking it out, and blow it dry with nitrogen. A CdS buffer layer is formed.

Then a layer of AZO film is sputtered; finally Ag is thermally evaporated on the AZO film as an electrode to obtain a flexible copper indium gallium selenide solar cell.

Fig. 2 is the current density-voltage (JV) characteristic curve of the flexible CIGS solar cell obtained in this comparative example. The test conditions are as follows: room temperature, atmospheric environment, spectral distribution AM1.5, light irradiation intensity 100mW/cm ² .

Example 1

As shown in Figure 2, the flexible perovskite-CIGS tandem solar cell of this embodiment includes a flexible copper indium gallium selenide cell as the bottom cell unit and a perovskite cell as the top cell unit, the top cell unit and the bottom cell are connected through an ITO interlayer. in:

The structure of the flexible copper indium gallium selenide battery is as follows from bottom to top: a flexible stainless steel substrate with a thickness of 30 μm, a metal electrode layer with a thickness of 500 nm, a CIGS light-absorbing layer film with a thickness of 1 μm, a CdS buffer layer with a thickness of 60 nm, and AZO with a thickness of 300 nm. film and a 100 nm thick Ag top electrode.

The thickness of the ITO interlayer is 40nm.

The structure of the perovskite battery from bottom to top is: 100nm thick PTAA hole transport layer, 500nm thick Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite light absorbing layer film, 30nm thick PCBM electron transport layer, 20nm thick C ₆₀ interface modification layer and 100 nm thick Ag top electrode.

The preparation method of the flexible perovskite-copper indium gallium selenide tandem solar cell in this embodiment is as follows:

(1) Preparation of flexible copper indium gallium selenide battery as the bottom battery unit

Referring to Comparative Example 1, the difference is that the Ag top electrode is not evaporated.

(2) Preparation of the middle layer

The ITO interlayer is sputtered on the AZO thin film of the flexible copper indium gallium selenide battery. Figure 4 is a scanning electron microscope image of the ITO interlayer.

(3) Preparation of perovskite battery as top cell unit

(31) Use double-sided tape to stick the substrate on the glass; add 8mg of PTAA powder to 1mL of chlorobenzene, stir at 60°C for 2h, and then spin-coat on the ITO intermediate layer (spin-coating speed is 2500rpm, time 30s, then placed on a heating platform and annealed at 90° C. for 5 min) to form a PTAA hole transport layer.

(32) Dissolve 0.645g of PbI ₂ powder and 0.024g of CsCl powder in 1mL of a mixed solution composed of DMF and DMSO at a volume ratio of 7:3, and stir at 70°C for 2h to form a precursor solution; on the PTAA hole transport layer First drop two drops of DMF solution for spin coating to improve wettability, then spin coat the precursor solution on the PTAA hole transport layer to form a film (spin coating speed is 4000rpm, time is 30s, followed by annealing at 100°C for 30min), and then Transfer the substrate to the tube furnace, and put 3g MAI powder in the tube furnace (the MAI powder is placed in the burning boat, and the substrate is placed on the bottom of the burning boat), using in-situ chemical vapor deposition (first vacuum , then heated up to 140°C, held for 60 minutes, and finally cooled to room temperature naturally, taken out and cleaned with isopropanol) to obtain a Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite light-absorbing layer film. Figure 5 is a scanning electron microscope image of the Cs _0.1 MA _0.9 PbI _2.9 Cl _0.1 perovskite light-absorbing layer film. It can be seen that the obtained film is uniform and dense.

(33) Add 20mg of PCBM powder into 1mL of chlorobenzene, stir at 60°C for 1h, and then spin coat (spin-coating speed is 3000rpm, time is 30s, followed by annealing at 60°C for 30min) on the perovskite light-absorbing layer film to form PCBM electron transport layer. Take 40mg of C ₆₀ powder and place it in a tungsten boat, fix the substrate on it, and thermally evaporate C ₆₀ under high vacuum as the interface modification layer. Then thermally evaporated Ag particles as the top electrode, that is, a flexible perovskite-copper indium gallium selenide tandem solar cell is obtained.

Fig. 6 is the current density-voltage (JV) characteristic curve of the flexible perovskite-copper indium gallium selenium tandem solar cell obtained in this embodiment, and the test conditions are as follows: room temperature, atmospheric environment, spectral distribution AM1.5, light irradiation intensity 100mW/cm ² .

Comparing this example with the comparative example, it can be seen that the addition of the perovskite top battery greatly increases the short-circuit current density value, thereby improving the battery efficiency.

The above are only exemplary embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention Inside.

Claims (8)

1. A flexible perovskite-copper indium gallium selenide laminated solar cell is characterized in that: the flexible copper indium gallium selenide battery comprises a flexible copper indium gallium selenide battery as a bottom battery unit and a perovskite battery as a top battery unit, wherein the top battery unit is connected with the bottom battery unit through an ITO (indium tin oxide) middle layer;

the structure of the flexible copper indium gallium selenide battery sequentially comprises the following components: a flexible stainless steel substrate with the thickness of 20-40 mu m, a Mo metal electrode layer with the thickness of 400-600nm, a CIGS light absorption layer film with the thickness of 1-2 mu m, a CdS buffer layer with the thickness of 400-600nm and an AZO film with the thickness of 200-300 nm;

the perovskite battery structure from bottom to top does in proper order: a PTAA hole transport layer with the thickness of 100-120 nm and Cs with the thickness of 500-600 nm _0.1 MA _0.9 PbI _2.9 Cl _0.1 Perovskite light absorption layer film, PCBM electron transmission layer with thickness of 30-40 nm, and C with thickness of 10-20 nm ₆₀ An interface modification layer, an Ag top electrode with the thickness of 100-150 nm;

the ITO intermediate layer is 30-50 nm.

2. A method for preparing the flexible perovskite-copper indium gallium selenide laminated solar cell as claimed in claim 1, which is characterized by comprising the following steps:

(1) Preparation of flexible copper indium gallium selenide battery serving as bottom battery unit

Firstly, sputtering a Mo metal electrode on a flexible stainless steel substrate, depositing a CIGS absorption layer film by using a multi-element co-evaporation method, preparing a CdS buffer layer by using a chemical water bath deposition method, and then sputtering an AZO film;

(2) Preparation of the intermediate layer

Sputtering an ITO intermediate layer on the AZO film of the flexible copper indium gallium selenide battery;

(3) Preparation of perovskite cells as top cell units

(31) Adhering the substrate to glass by using a double-sided adhesive tape; dissolving 6-10 mg of PTAA powder in 1mL of chlorobenzene, and then spin-coating the solution on the ITO intermediate layer to form a PTAA hole transport layer;

(32) 0.645g of PbI ₂ Dissolving the powder and 0.024g CsCl powder in 1mL of mixed solution consisting of DMF and DMSO according to the volume ratio of 7; spin-coating the precursor solution on the PTAA hole transport layer to form a film, transferring the substrate into a tube furnace, adding 3g of MAI powder into the tube furnace, and obtaining Cs by in-situ chemical vapor deposition _0.1 MA _0.9 PbI _2.9 Cl _0.1 A perovskite light absorption layer thin film;

(33) Dissolving 20-30 mg of PCBM powder in 1mL of chlorobenzene, and then spin-coating the solution on the perovskite light absorption layer film to form a PCBM electron transmission layer; thermally evaporating a layer C on the PCBM electron transport layer ₆₀ As an interface modification layer; and finally, evaporating Ag to be used as a top electrode, and obtaining the flexible perovskite-copper indium gallium selenide laminated solar cell.

3. The method for preparing the nano-particles according to claim 2, wherein the step of the chemical water bath deposition method in the step (1) comprises the following steps:

firstly, adding 100mL of deionized water into a beaker, weighing 0.0549g of cadmium chloride and 1.1418g of thiourea, adding 26mL of ammonia water with the mass concentration of 25-28%, and finally adding deionized water to a constant volume of 200mL to obtain a buffer layer precursor solution; and (3) heating the water bath to 60 ℃, soaking the substrate in the buffer layer precursor solution for 20min, taking out, washing the surface with deionized water, and drying with nitrogen to form the CdS buffer layer.

4. The production method according to claim 2, characterized in that: in the step (31), the PTAA is spin-coated at 2500-3000 rpm for 30-40 s, and then annealed at 90 ℃ for 5min.

5. The method of claim 2, wherein: in the step (32), the stirring temperature for forming the precursor solution is 70-90 ℃.

6. The method of claim 2, wherein: in the step (32), the spin coating speed of the precursor solution is 4000-5000 rpm, the time is 30-40 s, and then annealing is carried out for 30min at 100 ℃.

7. The method of claim 2, wherein: in step (32), the conditions of the in-situ chemical vapor deposition are as follows: firstly, vacuumizing to 1-100 Pa, then heating to 140-150 ℃, preserving heat for reaction for 60min, finally naturally cooling to room temperature, and taking out.

8. The method of claim 2, wherein: in the step (33), the spin coating speed for forming the PCBM electron transport layer is 3000-4000 rpm and the time is 30-40 s, and then annealing is carried out for 3min at 60 ℃.

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