WO2022127186A1 - High-stability tin-containing perovskite precursor solution, photoactive layer and battery, and preparation methods therefor - Google Patents

Abstract

Disclosed are a high-stability tin-containing perovskite precursor solution, a photoactive layer and a battery, and preparation methods therefor. By means of the present invention, a certain proportion of stannous acetylacetonate is added to the tin-containing perovskite precursor solution, and by means of the action of chelation coordination, Sn²⁺ is prevented from being oxidized into high-valence Sn⁴⁺, such that the photovoltaic performance of a tin-containing perovskite solar battery is improved.

Description

A kind of tin-containing perovskite precursor solution with strong stability, photoactive layer, battery and preparation method

This application is required to be submitted to the China Patent Office on December 15, 2020, the application number is 2020114902815, and the name of the invention is "a highly stable tin-containing perovskite precursor solution, photoactive layer, battery and preparation method" Chinese patent priority to the application, the entire contents of which are incorporated herein by reference.

technical field

The invention belongs to the field of optoelectronic materials, and in particular relates to a tin-containing perovskite precursor solution, a photoactive layer, a battery and a preparation method with strong stability.

Background technique

Organic-inorganic hybrid lead halide perovskite materials have been brilliant in the photovoltaic field due to their excellent properties, such as large absorption coefficient, long carrier diffusion length, tunable band gap, and easy preparation. However, the toxicity of lead has become an obstacle to its further commercialization. Tin-containing perovskites can reduce the lead content, and theoretically, tin-containing perovskites can obtain more suitable band gaps than pure lead perovskites, and can also be used as light-absorbing layers for sub-cells of tandem cells. However, the characteristics of Sn ²⁺ being easily oxidized to Sn ⁴⁺ make tin-containing perovskites form self-doping, increase the density of defect states, and reduce the performance of photovoltaic devices. This property of tin-containing perovskites hinders its wider application. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of tin-containing perovskite precursor solution, photoactive layer, battery and preparation method with strong stability, in order to overcome the problems of the prior art, the present invention adds a certain amount of tin-containing perovskite precursor solution The proportion of stannous acetylacetonate inhibits the oxidation of Sn ²⁺ to high-valent Sn ⁴⁺ through chelating coordination, thereby improving the photovoltaic performance of tin-containing perovskite solar cells.

To achieve the above object, the present invention adopts the following technical solutions:

A kind of tin-containing perovskite precursor solution with strong stability, its preparation raw material includes solute and solvent, and the solvent is a mixed solvent of DMF and DMSO, and the solute includes FAI, MAI, PbI ₂ , SnI ₂ , tin powder and Stannous acetylacetonate, wherein the volume ratio of DMF and DMSO is 6:4, and 216.72mg FAI, 85.86mg MAI, 414.90mg PbI ₂ , 335.25mg SnI ₂ , 5mg tin powder and 0.28mg- 1.43 mg stannous acetylacetonate.

A preparation method of a tin-containing perovskite precursor solution with strong stability. Dissolving FAI, MAI, PbI ₂ , SnI ₂ , tin powder and stannous acetylacetonate in a mixed solvent, stirring until completely dissolved, the stability is obtained. Strong tin-containing perovskite precursor.

A preparation method of a photoactive layer, the tin-containing perovskite precursor solution with strong stability is filtered to remove the tin powder, the precursor solution of the tin powder is filtered by a one-step spin coating, and after the spin coating is completed, the hot plate is annealed to obtain photoactive layer.

Further, the rotational speed during spin coating was 4000 r.p.m, the spin coating time was 35 s, and the anti-solvent ethyl acetate was added dropwise 15 s before the end of the spin coating procedure.

Further, the annealing temperature of the hot plate was 100° C., and the time was 30 min.

A perovskite solar cell comprises a transparent electrode substrate, a first charge transport layer, a photoactive layer, a second charge transport layer and a metal back electrode which are arranged in sequence from bottom to top.

A preparation method of a perovskite solar cell, comprising the following steps:

Step 1: Take the ITO glass substrate, and sequentially use deionized water, acetone, and isopropanol to ultrasonically treat the surface of the ITO glass substrate, blow dry with a nitrogen stream, and then clean with ultraviolet light to obtain a transparent electrode substrate;

Step 2: spin-coating the PEDOT:PSS precursor solution on the transparent electrode substrate, and then hot plate annealing to obtain the first charge transport layer;

Step 3: preparing a photoactive layer on the first charge transport layer;

Step 4: preparing C ₆₀ /BCP as the second charge transport layer on the photoactive layer by vapor deposition;

Step 5: An Ag layer is prepared on the second charge transport layer as a metal back electrode by vapor deposition.

Further, in step 2, the annealing temperature of the hot plate is 120° C., and the time is 30 minutes.

Further, the thickness of the first charge transport layer in step 2 is 35 nm, and the thickness of the photoactive layer in step 3 is 800-1000 nm.

Further, the thickness of C ₆₀ in step 4 is 45 nm, the thickness of BCP is 8 nm, and the thickness of metal back electrode in step 5 is 100 nm.

Compared with the prior art, the present invention has the following beneficial technical effects:

In the present invention, a certain proportion of stannous acetylacetonate is added as an additive in the tin-containing perovskite precursor solution, and the oxidation of low-valent Sn ²⁺ in the precursor solution can be effectively suppressed through the bidentate chelation coordination effect of the acetylacetone group. It is high-valent Sn ⁴⁺ , thus improving the stability of the precursor solution.

The advantage of the photoactive layer prepared by the precursor solution containing the additive is that the oxidation of Sn ²⁺ to Sn ⁴⁺ can be suppressed, the self-doping degree of the photoactive layer is reduced, and the defect density of the photoactive layer is reduced.

Since the self-doping degree of the photoactive layer is reduced, the defect density of the photoactive layer is reduced, so that the battery prepared based on this photoactive layer can improve the photoelectric performance of the device on the one hand, and the stability of the device on the other hand. promote.

Description of drawings

Figure 1 is a schematic diagram of the structure of a perovskite solar cell;

Fig. 2 is stannous acetylacetonate structural diagram;

102 is a first charge transport layer; 103 is a photoactive layer; 104 is a second charge transport layer; 105 is a metal back electrode;

FIG. 3 is a graph of the cell efficiency when the cell is not packaged.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below with reference to the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

The invention provides an additive strategy, which can inhibit low-valent Sn ²⁺ in the tin-containing perovskite precursor liquid from being easily oxidized to high-value Sn ⁴⁺ , and improve the stability of the precursor liquid. The invention is in the tin-containing perovskite precursor liquid. Adding a certain proportion of stannous acetylacetonate inhibits the oxidation of Sn ²⁺ into high-valent Sn ⁴⁺ through chelating coordination, thereby improving the photovoltaic performance of tin-containing perovskite solar cells.

Specifically, a kind of tin-containing perovskite precursor solution with strong stability, the preparation raw material includes a solute and a solvent, the solvent is a mixed solvent of DMF and DMSO, and the solute includes FAI, MAI, PbI ₂ , SnI ₂ , Tin powder and stannous acetylacetonate, wherein the volume ratio of DMF and DMSO is 6:4, and 216.72 mg of FAI, 85.86 mg of MAI, 414.90 mg of PbI ₂ , 335.25 mg of SnI ₂ , 5 mg of tin powder and 0.28mg-1.43mg stannous acetylacetonate.

During preparation, FAI, MAI, PbI ₂ , SnI ₂ , tin powder and stannous acetylacetonate are dissolved in a mixed solvent, and stirred until completely dissolved to obtain a tin-containing perovskite precursor solution with strong stability.

A preparation method of a photoactive layer, the tin-containing perovskite precursor solution with strong stability is filtered to remove the tin powder, and the precursor solution of the tin powder is filtered by a one-step spin coating, and the rotation speed is 4000r.p.m during the spin coating, and the spin coating is performed. The time is 35s, and the anti-solvent ethyl acetate is added dropwise 15s before the end of the spin coating procedure. After the spin coating is completed, the hot plate is annealed, the annealing temperature is 100° C., and the time is 30 minutes, to obtain a photoactive layer.

The present invention also provides a perovskite solar cell as shown in Figure 1, the structure of which is composed of the following parts:

1. Transparent electrode substrate 101: ITO glass substrate, the area is not limited (2×2 cm ² in this example), such products can be directly used as commercial products in large-scale mass production. Before use, the surface of the ITO glass substrate should be ultrasonically treated with deionized water, acetone, and isopropanol in sequence for 15 minutes, dried with nitrogen flow, and then cleaned with a UV light cleaning machine for 10 minutes;

2. The first charge transport layer 102: spin-coating a PEDOT:PSS (model: PEDOT:PSS4083A) precursor solution on an ITO substrate, followed by hot plate annealing (120°C, 30min); the thickness is 35nm;

3. The photoactive layer 103: the tin-lead mixed organic-inorganic hybrid metal halide perovskite FA _0.7 MA _0.3 Pb _0.5 Sn _0.5 I ₃ is used as the light absorbing layer, and the preparation method of the precursor solution is as follows: FAI (216.72 mg), MAI (85.86mg), PbI ₂ (414.90mg), SnI ₂ (335.25mg), tin powder 5mg, tin acetylacetonate 0.1-0.5mol% (relative to SnI ₂ ), dissolved in 1mL mixed solvent volume ratio (DMF:DMSO =6:4), stir until completely dissolved, filter out the tin powder before use, and prepare it on the first charge transport layer 102 by one-step spin coating (4000 rpm, 35s, add anti-solvent dropwise 15s before the end of the spin coating procedure Ethyl acetate); after spin-coating, annealing at 100° C. for 30 min to obtain a photoactive layer 103 with a thickness of 800-1000 nm;

4. The second charge transport layer 104: prepare C ₆₀ /BCP as the second charge transport layer 104 on the photoactive layer 103 by vapor deposition, wherein the thickness of C ₆₀ is 45 nm and the thickness of BCP is 8 nm;

5. Metal back electrode 105: Ag is prepared on the second charge transport layer 104 by means of vapor deposition as the metal back electrode 105 with a thickness of 100 nm.

As shown in Figure 3, when the battery is placed in the glove box without packaging, the battery efficiency can still maintain above 85%.

Table 1 Battery performance data table with different stannous acetylacetonate content

  Voc(V) Jsc(mA/cm ² ) FF(%) Eff(%) 0.1mol stannous acetylacetonate 0.78 25.8 0.75 15.09 0.3mol stannous acetylacetonate 0.83 27.9 0.78 18.06 0.5mol stannous acetylacetonate 0.81 26.2 0.61 12.95

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

A tin-containing perovskite precursor solution with strong stability, characterized in that its preparation raw materials include a solute and a solvent, the solvent is a mixed solvent of DMF and DMSO, and the solute includes FAI, MAI, PbI ₂ , SnI ₂ , tin powder and stannous acetylacetonate, wherein the volume ratio of DMF and DMSO is 6:4, and 216.72mg FAI, 85.86mg MAI, 414.90mg PbI ₂ , 335.25mg SnI ₂ , 5mg tin powder are added to every 1 mL of mixed solvent and 0.28mg-1.43mg stannous acetylacetonate. The method for preparing a stable tin-containing perovskite precursor solution according to claim 1, wherein FAI, MAI, PbI ₂ , SnI ₂ , tin powder and stannous acetylacetonate are dissolved in a mixed solvent , and stir until it is completely dissolved, that is, a tin-containing perovskite precursor solution with strong stability is obtained. A preparation method of a photoactive layer, characterized in that, based on the tin-containing perovskite precursor solution with strong stability according to claim 1, the tin-containing perovskite precursor solution with strong stability is filtered to remove tin powder , adopt one-step spin coating to filter the precursor liquid of tin powder, after spin coating, hot plate annealing to obtain the photoactive layer. The preparation method of a photoactive layer according to claim 3, characterized in that, during spin coating, the rotating speed is 4000 r.p.m, the spin coating time is 35 s, and the anti-solvent ethyl acetate is added dropwise 15 s before the end of the spin coating procedure. The method for preparing a photoactive layer according to claim 3, wherein the annealing temperature of the hot plate is 100° C. and the time is 30 minutes. A perovskite solar cell is characterized in that, the photoactive layer obtained based on the preparation method of a photoactive layer according to any one of claims 3-5 comprises a transparent electrode substrate ( 101), a first charge transport layer (102), a photoactive layer (103), a second charge transport layer (104) and a metal back electrode (105). The preparation method of a kind of perovskite solar cell according to claim 6, is characterized in that, comprises the following steps: Step 1: take an ITO glass substrate, and sequentially use deionized water, acetone, and isopropanol to ultrasonically treat the surface of the ITO glass substrate, blow dry with a nitrogen stream, and then clean with ultraviolet light to obtain a transparent electrode substrate (101); Step 2: spin-coating the PEDOT:PSS precursor solution on the transparent electrode substrate (101), followed by hot plate annealing to obtain a first charge transport layer (102); Step 3: preparing a photoactive layer (103) on the first charge transport layer (102); Step 4: prepare C ₆₀ /BCP as the second charge transport layer ( 104 ) on the photoactive layer ( 103 ) by vapor deposition; Step 5: An Ag layer is prepared on the second charge transport layer (104) by means of evaporation as a metal back electrode (105). The method for preparing a perovskite solar cell according to claim 7, wherein the annealing temperature of the hot plate in step 2 is 120° C. and the time is 30 minutes. The method for preparing a perovskite solar cell according to claim 7, wherein the thickness of the first charge transport layer (102) in step 2 is 35 nm, and the thickness of the photoactive layer (103) in step 3 is 800-1000nm. The method for preparing a perovskite solar cell according to claim 8, wherein in step 4, the thickness of _C60 is 45 nm, the thickness of BCP is 8 nm, and the thickness of the metal back electrode (105) in step 5 is 100nm.

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