TW201912253A - Method for making perovskite thin film by ultrasonic spray-coating technique and method for making solar cell - Google Patents

Abstract

The present invention relates to a method for making perovskite thin film by using ultrasonic spray-coating technique, comprising (a) spraying a first solution on a plate to form a perovskite thin film; or (b) spraying a second solution on a plate to form a film and then spraying a third solution on the film to form a perovskite thin film. The present invention also relates to a method for making a solar cell using the perovskite thin film disclosed foregoing. Compare to the prior art, the method of the present invention has higher availability on materials and can be easily adopted for large scale perovskite cells and integrated with roll-to-roll mass production. The invention based on ultrasonic spray-coated large area perovskite thin film has good uniform and reproducibility and its device application is now still ongoing.

Description

 Perovskite film produced by ultrasonic spraying method and manufacturing method of solar cell  

The invention relates to a method for preparing a perovskite film, in particular to a perovskite film produced by ultrasonic spraying technology and a method for manufacturing the solar cell using the same.

Since the industrial revolution, human beings have become more and more demanding for electricity. However, the development of energy may cause serious environmental threats. Therefore, in recent years, renewable energy with low environmental impact has become a promising project in the field of energy development. .

There are many types of renewable energy sources, such as tidal, wind, geothermal and solar energy. Among them, solar cells, which are more free from terrain and geographical constraints, and which are free to design volume and appearance, are most widely used. At present, the main types of solar cells are germanium-based solar cells, III-V thin film solar cells, CIGS thin film solar cells, organic thin film solar cells, and Dye Sensitized Solar Cells (DSSC). According to its power generation efficiency and cost classification, the first generation of high-efficiency and high-cost twin solar cells is dominated by germanium, followed by GaAs; the second generation is low-efficiency and low-cost thin-film solar cells; The code is a high efficiency and low cost solar cell, including dye-sensitized solar cells and organic thin film solar cells.

Among them, Dye Sensitized Solar Cell (DSSC) is a new form of solar cell system made by mixing organic dye with inorganic titanium dioxide (TiO ₂ ), which is different from the solar cell principle of pn junction, but similar Simulated photosynthesis. DSSC does not require expensive vacuum system equipment, and the process is relatively simple, which has great potential compared with traditional solar cells.

Perovskite is an emerging material for solar cells. Perovskite is applied to solar cells with the following advantages: (1) long carrier diffusion length, fast speed, and (2) exciton binding energy is small ( 3) High output voltage efficiency, (4) high ability to absorb light, (5) easy adjustment of energy gap, (6) easy fabrication and low cost, therefore suitable for active layer of solar cell as good hole transfer material And the perovskite solar cell system uses a solution process, which is simple to manufacture and the equipment is not very expensive, and the power generation efficiency has reached the level of commercialization. After continuous improvement by national research teams, the internationally recognized highest conversion efficiency has reached 22%. It is a new hope for solar cells.

However, in the production of the active layer of the solar cell, the general spin coating method is difficult to achieve large-area production, and the material utilization is poor, while the conventional spraying method, such as the traditional two-fluid spraying method, is easy to cause the spraying fluid during the process. The rebound rate, or the problem of scattering around, the material utilization rate is only 30-50%.

In order to solve the above problems, the main object of the present invention is to provide a method for producing a perovskite film by using ultrasonic spraying (1) a first solution to form a perovskite film on a substrate (hereinafter referred to as a "one-step method"; or (2) a second solution is formed on a substrate, and a third solution is sprayed on the film formed by the second solution (hereinafter referred to as "two-step method") to A perovskite film is formed.

In a preferred embodiment, the solute of the first solution is BX ₂ and AX, wherein A is an organic cation, B is a metal cation and X is a halogen group, and the molar ratio of the BX ₂ and AX is 1:0.8. To 1:1.2.

In a preferred embodiment, the solvent of the first solution is dimethyl hydrazine (DMSO) and γ-butyrolactone (GBL) in a mixing volume ratio of 10:0 to 3:7.

In a preferred embodiment, the solute of the second solution is BX ₂ , wherein B is a metal cation and X is a halogen group; and the solvent of the second solution comprises dimethylformamide (DMF) and dimethyl Agaride (DMSO) has a mixed volume ratio of 10:0 to 3:7.

In a preferred embodiment, the solute of the third solution is AX, wherein A is an organic cation and X is a halogen group, and the solvent of the third solution is isopropyl alcohol.

Another object of the present invention is to provide a method for fabricating a solar cell, the method comprising: (a) spin coating a first carrier transport layer on a conductive substrate; (b) forming a perovskite using the method described above a thin film active layer on the first carrier transport layer; (c) vapor deposition to form a second carrier transport layer on the active layer of the perovskite film; (d) vapor deposition to form a hole barrier layer in the first And (e) vapor deposition to form an electrode layer on the hole barrier layer.

In a preferred embodiment, the conductive substrate is selected from the group consisting of fluorine doped tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , and ZnO-Al ₂ O. _3. A group consisting of tin oxide and zinc oxide.

In a preferred embodiment, the first carrier transport layer is a hole transport layer, the material of which is selected from the group consisting of 2,2',7,7'-tetra-(N,N-di-p-methoxybenzene). Ethylamine) 9,9 spiro-OMeTAD, poly(3,4-diethoxydithio)-polystyrenesulfonic acid (PEDOT:PSS), N,N'-di(3-A a group consisting of phenyl)-N,N'-diphenyl-[1,1'-biphenyl 1-4,4'-diamine (TPD) and polytrihexyl polythiophene (P3HT); The second carrier transport layer is an electron transport layer, the material of which comprises carbon-60 (C ₆₀ ), ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid methyl ester.

In a preferred embodiment, the material of the hole barrier layer comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-two. Phenyl-1,10-phenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 1,3,5-tris(4-pyridin- 3 -ylphenyl)benzene (1,3, 5-tri(p-pyrid-3-yl-phenyl)benzene, TpPyPB) or diphenyl bis[4-(pyridin-3-yl)phenyl]decane (diphenyl bis(4-(pyridin-3-yl)) Phenyl)silane, DPPS).

In a preferred embodiment, the electrode layer is a counter electrode layer, and the material of the counter electrode layer is selected from the group consisting of copper, gold, silver, rhodium, palladium, nickel, molybdenum, aluminum, alloys thereof, and multilayer materials thereof. The group formed.

The invention uses the ultrasonic spraying technology to produce a perovskite film and a solar cell, which uses the ultrasonic vibration technology to first refine the coating, and then accumulates the atomized material on the surface of the target through a carrier gas. The invention forms a film, and the invention has higher utilization of the spraying raw material than the prior art, and is also easy to realize large-area production, and can be connected with the roll-to-roll process, and the spraying effect is also more detailed, and has a large-scale preparation process. And the potential of low-cost perovskite solar cells.

1‧‧‧Electrical substrate

11‧‧‧floor

12‧‧‧Working electrode

2‧‧‧First carrier transfer layer

3‧‧‧ Perovskite film

4‧‧‧Second carrier transfer layer

5‧‧‧ hole barrier

6‧‧‧electrode layer

7‧‧‧Ultrasonic nebulizer

8‧‧‧heating plate

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the material of each layer in the third embodiment of the present invention.

Figure 2 is a perspective view showing the structure of the third and fourth embodiments of the present invention.

3 is a top plan view showing a patterned conductive substrate according to third and fourth embodiments of the present invention.

Fig. 4 is a top plan view showing a second solution spraying path according to a fourth embodiment of the present invention.

Fig. 5 is a top plan view showing a third solution spraying path according to a fourth embodiment of the present invention.

Fig. 6 is a plan view showing the electrode layer preparation region of the third and fourth embodiments of the present invention.

Fig. 7 is a top plan view showing a solar cell according to a third and fourth embodiment of the present invention.

Figure 8 is a (a) SEM image of a different first solution concentration according to a third embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum; (d) J-V curve.

Figure 9 is a (a) SEM image of a different first solution solute ratio according to a third embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum; (d) J-V curve.

Figure 10 is a (a) SEM image showing the ratio of different first solution solvents in the third embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum; (d) J-V curve.

Figure 11 is a (a) SEM image using different thermal annealing temperatures in accordance with a third embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum; (d) J-V curve.

Figure 12 is a diagram showing the relationship between the thickness of the perovskite film and the concentration of the second solution using the SEM of different second solution concentrations in the fourth embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum ; (d) JV curve.

Figure 13 is a (a) SEM image of a second solution solvent ratio according to a fourth embodiment of the present invention; (b) UV-Vis absorption spectrum; (c) J-V curve.

Figure 14 is a (a) SEM image of a fourth solution concentration according to a fourth embodiment of the present invention; (b) XRD pattern-1; (c) XRD pattern-2; (d) UV-Vis absorption spectrum.

Figure 15 is a (a) surface SEM image using different thermal annealing temperatures according to a fourth embodiment of the present invention; (b) XRD pattern; (c) UV-Vis absorption spectrum; (d) JV curve; (e) section SEM image.

Figure 16 is a (a) XRD pattern of different thermal annealing times in accordance with a fourth embodiment of the present invention; (b) UV-Vis absorption spectrum; (c) J-V curve.

The detailed description and technical contents of the present invention will now be described with reference to the drawings. In addition, the drawings in the present invention are for convenience of description, and the ratios thereof are not necessarily drawn to actual scales, and the drawings and their proportions are not intended to limit the scope of the present invention, and are described herein.

The word "comprising" or "comprises" or "an" or "an" "About or close" or "substantially" means having a value or range that is close to the allowable specified error to avoid any unreasonable use by third parties, illegal or unfair use, to understand the precise or absolute value disclosed herein. "One" means that the grammatical object of the object is one or more (ie, at least one).

The invention provides a method for preparing a perovskite film, which uses ultrasonic spraying (1) a first solution to form a perovskite film on a substrate; or (2) a second solution on a substrate. Film formation is performed, and a third solution is sprayed on the film formed by the second solution to form a perovskite film.

As used herein, "perovskite" refers to perovskite materials that are organically and inorganicly mixed, which can be used as an active layer of a solar cell, and are referred to as "perovskite solar cells." The perovskite structure has the general formula ABX ₃ , wherein A is an organic cation used to offset the negative charge to make the crystal lattice electrically neutral, such as HC(NH ₂ ) ²⁺ referred to as FA ⁺ or CH ₃ NH ₃ ⁺ MA ⁺ etc., B is a metal cation such as Pb ²⁺ , Ge ²⁺ , Sn ^{2+ ,} etc., X is a monovalent anion, preferably a halogen group such as: I ^- , Br ^- , Cl ^- etc. The invention is not limited to this. The perovskite can be prepared by first preparing a precursor to form a perovskite. The chemical reaction formula is as follows: AX+BX ₂ → ABX ₃

In a preferred embodiment, the precursors AX and BX ₂ are methylamine iodine (CH ₃ NH ₃ I) and lead iodide (PbI ₂ ), respectively, and the ABX ₃ is formed as CH ₃ NH ₃ Pbl _{3 .} However, the invention is not limited thereto. The three-dimensional structure of the perovskite is usually composed of an inorganic cation at the B site and an inorganic anion at the X site, and the organic cation at the A site is located at the eight vertices of the cube, compared to the structure of the coplanar form. The structure of the perovskite is more stable and facilitates the diffusion and migration of defects.

The term "first solution" as used herein refers to a precursor solution of a perovskite film produced by a one-step process, which is AX and BX ₂ in the chemical formula of perovskite, AX such as FACl, FABr, FAI, MACl , MABr, MAI, etc.; BX ₂ For _{example: PbCl 2, PbBr 2, PbI} 2, GeCl 2, GeBr 2, GeI 2, SnCl 2, SnBr 2, SnI 2 and the like. In a preferred embodiment, the concentration (wt%) of the first solution is from 9 to 21% by weight, preferably 15% by weight. In a preferred embodiment, the first solution solute AX is lead iodide (PbI ₂ ), BX ₂ methylamine iodine (CH ₃ NH ₃ I), and the lead iodide (PbI ₂ ) and The molar ratio of the amide iodide (CH ₃ NH ₃ I) is from 1:0.8 to 1:1.2, such as 1:0.8, 1:0.9, 1:1, 1:1.1 and 1:1.2, preferably 1:1. However, the invention is not limited thereto. The solvent of the first solution is selected from the group consisting of dimethyl sulfoxide (DMSO), gamma-butyrolactone (GBL), dimethylformamide (DMF), N-methyl-2- a group consisting of pyrrolidone (NMP), acetonitrile, dimethylacetamide (DMA _C ), isopropanol, and any combination thereof, in another preferred embodiment, the solvent of the first solution Dimethyl hydrazine (DMSO) and γ-butyrolactone (GBL) are used, and the mixing volume ratio thereof is preferably 10:0 to 3:7, for example, 10:0, 10:3, 10:7, 9 : 1, 9:5, 9:7, 8:1, 8:3, 8:5, 8:7, 7:1, 7:3, 7:5, 6:1, 6:5, 6:7 , 5:1, 5:2, 5:3, 5:4, 5:5, 5:6, 5:7, 5:8, 5:9, 4:1, 4:3, 4:5, 4 : 7, 3:1, 3:5, 3:7, 2:1, 2:3, 2:5, 2:7, 1:3, 1:5 and 1:7, etc., preferably 5:5 However, the invention is not limited thereto.

The herein, the "second solution" means two-step method to produce a thin film precursor solution of perovskite, perovskite which in the general chemical formula BX _2, for _{example: PbCl 2, PbBr 2, PbI} 2, GeCl _{2, GeBr 2, GeI 2,} SnCl 2, SnBr 2, SnI 2 , etc., in a preferred embodiment, the second solution of the solute BX ₂ based lead iodide (PbI _2), and in another preferred embodiment In the example, the concentration of the solute BX ₂ is 9 to 15% by weight, such as 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and more preferably 11 wt%. The solvent of the second solution is selected from the group consisting of dimethyl sulfoxide (DMSO), gamma-butyrolactone (GBL), dimethylformamide (DMF), N-methyl-2. a group consisting of pyrrolidone (NMP), acetonitrile, dimethylacetamide (DMA _C ), isopropanol, and any combination thereof, in a preferred embodiment, a solvent for the second solution Containing dimethylformamide (DMF) and dimethylhydrazine (DMSO) in a mixed volume ratio of 10:0 to 3:7, for example: 10:0, 10:3, 10:7, 9:1 , 9:5, 9:7, 8:1, 8:3, 8:5, 8:7, 7:1, 7:3, 7:5, 6:1, 6:5, 6:7, 5 : 1, 5: 2, 5: 3, 5: 4, 5: 5, 5: 6, 5: 7, 5: 8, 5: 9, 4: 1, 4: 3, 4: 5, 4: 7 , 3:1, 3:5, 3:7, 2:1, 2:3, 2:5, 2:7, 1:3, 1:5 and 1:7, preferably 5:5, but this The invention is not limited to this. DMF has a lower boiling point (154 ° C), while GBL is 204 ° C. The relatively low boiling point of DMF is beneficial to the formation of perovskite film.

The "third solution" as used herein refers to a precursor solution of a perovskite film produced by a two-step process, which is a AX in the perovskite chemical formula, for example: FACl, FABr, FAI, MAC1, MABr, MAI In a preferred embodiment, the solute of the third solution is methylamine iodine (CH ₃ NH ₃ I, MAI), and in another preferred embodiment, the concentration of the third solution is 0.5~ 2 wt%, and more preferably 1 wt%. The solvent of the third solution is selected from the group consisting of dimethyl sulfoxide (DMSO), gamma-butyrolactone (GBL), dimethylformamide (DMF), N-methyl-2. a group consisting of pyrrolidone (NMP), acetonitrile, dimethylacetamide (DMA _C ), isopropanol, and any combination thereof, in a preferred embodiment, the solvent of the third solution Is isopropyl alcohol.

The "ultrasonic spray-coating" described in this paper is highly refinement of the coating solution by ultrasonic vibration. The principle of operation uses the ultrasonic generator to release high-frequency electronic signals (about 20 to 200 kHz). The piezoelectric ceramic generates mechanical vibration of the same frequency and amplifies the amplitude through the horn, thereby forming micron-sized droplets (the video ratio can be as small as 20 μm or less) from the atomized slurry. When the working fluid enters the exit of the ultrasonic nozzle (the maximum end of the displacement), a standing wave is formed on the surface. As the energy increases, the fluid at the peak will form a droplet from the surface, thereby atomizing the particle. A film is deposited on the surface, and the coating is applied to the coating by a related process such as baking. It is equipped with a three-axis mobile platform, which can be edited into a series of process movement instructions through pre-designed Java command code, so that many complicated spray path processes can be produced. It has the characteristics of simple operation, low cost and high output.

In addition to the spraying technique, the thermal annealing process is also a crucial step for the solvent process, which can start or accelerate the alignment of the molecules to form a thin film; the present invention is found to be a one-step method and a two-step method. 90 ° C, 100 ° C, 110 ° C, 120 ° C and 130 ° C, wherein 110 ° C for a one-step process, preferably 100 ° C for a two-step process, and thermal annealing time, one step method is preferred but not limited to 30 In minutes, the two-step method is preferably but not limited to 20 minutes.

The invention further provides a method for fabricating a solar cell, the method comprising: (a) spin coating a first carrier transport layer on a conductive substrate; (b) forming a perovskite film using the method of the invention The active layer is on the first carrier transport layer; (c) vapor deposition forms a second carrier transport layer on the active layer of the perovskite film; (d) vapor deposition forms a hole barrier layer in the second layer And (e) vapor deposition to form an electrode layer on the hole barrier layer.

The term “conductive substrate” as used herein refers to a substrate having a conductive effect, which can be combined with a conductive material by means of mixing, coating, coating, etc. in a supporting substrate. However, the method of bonding the substrate to the conductive material is not To be limited, the bottom plate may be a flexible or inflexible material such as glass, ceramic, metal or plastic, and the invention is not limited thereto. The conductive substrate is selected from the group consisting of fluorine doped tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide and zinc oxide. The group formed.

The "first carrier transfer layer" described herein is a hole transfer layer in a preferred embodiment, which has a high hole mobility and has an interface energy barrier with the electrode layer and is easy to be injected into the hole. It may be doped with molybdenum oxide (MoO _x ), vanadium oxide (V ₂ O ₅ ), nickel oxide (NiO), tungsten oxide (WO _x ) and the like; or an aromatic tertiary amine compound, preferably selected Free 2,2',7,7'-tetra-(N,N-di-p-methoxyphenethylamine) 9,9 spiro-OMeTAD, poly(3,4-diethoxydioxy) Thiophene)-polystyrenesulfonic acid (PEDOT:PSS), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]- A group consisting of 4,4'-diamine (TPD) and polytrihexyl polythiophene (P3HT).

The "second carrier transfer layer" described herein is used as an electron transport layer for transferring separated electrons from the active layer to the electrode, which has high electron mobility and the material can be metal. oxides, and complexes of Alq3 or Balq, preferably comprising a carbon-based _{-60 (C 60), ZnO,} TiO 2 , or [6.6] - phenyl-butyric acid methyl ester -C61-.

The "hole blocking layer" described herein is used to prevent the hole from moving toward the electrode layer, and the material thereof may be an aluminum compound, a gallium compound, a phenanthroline derivative, a pyrene derivative, or a hydroxyquinoline derivative. a compound, a diazole derivative, an azole derivative, preferably comprising 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-di Phenyl-1,10-phenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 1,3,5-tris(4-pyridin-3-ylphenyl)benzene (1,3, 5-tri(p-pyrid-3-yl-phenyl)benzene, TpPyPB) or diphenyl bis[4-(pyridin-3-yl)phenyl]decane (diphenyl bis(4-(pyridin-3-yl)) Phenyl)silane, DPPS).

In the preferred embodiment, the "electrode layer" described herein is used as a counter electrode layer, and the electrode layer may be a metal having a low work function, and the material of the pair of electrode layers is selected from the group consisting of copper, gold, silver, and antimony. A group consisting of palladium, nickel, molybdenum, aluminum, alloys thereof, and multilayer materials comprising the same.

The "J-V curve" described herein refers to the characteristic curve of the solar cell current and voltage obtained by the solar simulation source under the fixed illumination intensity, which is used to quantify the performance of the solar cell and analyze whether the performance is excellent. Before measuring the efficiency of the solar cell, the present invention firstly uses a twin-type reference battery to correct the simulated solar light intensity to a solar radiation spectrum of 1 sunlight (1SUN) when AM 1.5G (Global), and the fixed simulator lamp The height of the source to the surface of the battery element is 12 cm to start the efficiency measurement. The given voltage setting starting point is -0.1V, the ending point is 1.0V, and the scanning rate is 0.1V/s.

The term "Short Circuit Current Density (J _SC )" as used herein refers to a situation in which the solar cell is in a short-circuit state when the solar cell is not loaded, and the current is called a short circuit. For the short-circuit current (I _SC ), the short-circuit current is divided by the illumination area of the component to obtain the short-circuit current density.

The term "Open Circuit Voltage (V _OC )" as used herein means that after the load is applied to the solar cell, that is, the load resistance is not zero, and when the load resistance is infinite, the net current of the circuit is zero. The voltage generated at the time is the open circuit voltage. If the material of the light absorbing layer of a solar cell has many impurities or defects, it is easy to cause the light/dark current ratio of the element to drop and the appropriate open circuit voltage value cannot be obtained.

"Fill Factor (FF)" as used herein refers to the ratio of the actual maximum power point (P _max ) to the product of V _OC and J _SC , that is, the maximum voltage output point (V _max ) and the maximum current density output point. The product of (J _max ) (ie, the actual maximum power point P _max ) divided by the product of V _OC and J _SC (ie, the ideal power of the solar cell). The larger the fill factor value is, the closer the voltage current curve of the solar cell is to the ideal diode, that is, the closer the voltage current curve is to the right angle type.

"Power Conversion Efficiency (PCE)" as used herein refers to substituting short-circuit current, open-circuit voltage, and fill factor into the following equations:

Among them, the incident sunlight intensity (P _light ) is defined according to international standards, and the range is the air mass of the solar radiation at AM 1.5 and the temperature of 25 ° C, and the P _light is 100 mW/cm ² .

Hereinafter, the present invention will be further described in detail with reference to the embodiments. However, it is to be understood that these examples are only intended to facilitate the understanding of the invention and are not intended to limit the scope of the invention.

[Preparation example]

Experimental drugs and materials

1. ITO glass: purchased from Ruilong Optoelectronics Co., Ltd., the sheet resistance is about 10Ω.

2. Lead iodide: purchased from Alfa Aesar, with a purity of 99.9985%.

3. Methylamine iodine: purchased from Dyesol, with a purity of >98%.

4. PEDOT: PSS: purchased from Heraeus, AI-4083.

5. Fullerene (C60): purchased from Solenne, the Netherlands, with a purity of 99.5%.

6. BCP: purchased from Lumtec, with a purity of >99%.

7. DMF: purchased from Aldrich, anhydrous, with a purity of 99.8%.

8. DMSO: purchased from Aldrich, anhydrous, purity 99.9%.

9. Isopropanol (IPA): purchased from Aldrich, anhydrous, with a purity of 99.5%.

10. Acetone: purchased from Jingming Chemical, ACS, purity 99.5%.

laboratory apparatus

1. Plasma cleaner: Harrick Plasma, USA, PDC-32G type.

2. Rotary coating machine: TOP TECH, TR-15 type.

3. Ultrasonic nebulizer: Sono-Tek, USA, 120kHz type.

4. Heating plate: YOTEC, YS200S.

5. Customized three-axis mobile platform: 昱展科技.

6. High vacuum thermal evaporation equipment: Gao Dun Technology, KD-THERMAL type.

7. Solar simulator and efficiency measurement system: Enlitech, YSS-50.

8. X-ray diffractometer (XRD): Bruker, D8A, with copper (Cu) K _alpha rays.

9. UV/Vis spectrometer: JASCO company V-670.

10. Field emission scanning electron microscope (SEM): JEOL, JSM-7600F.

First solution configuration

In a preferred embodiment, the solute of the first solution of the present invention is lead iodide (PbI ₂ ) and methylamine iodine (CH ₃ NH ₃ I), and the solvent is dimethyl sulfoxide (DMSO) and γ- Butyrolactone (GBL). In order to further test the better formulation, different solute concentrations, different solute ratios and different solvent ratios were formulated.

The molar ratio of the fixed solute lead iodide (PbI ₂ ) and methylamine iodine (CH ₃ NH ₃ I) is 1:1, and the weight percent concentration of the total solute is changed, which are 9 wt%, 12 wt%, 15 wt%, respectively. 18 wt% and 21 wt%, and the annealing temperature in the subsequent spraying process (as shown in the table) was fixed for 30 minutes, and the formulation thereof is shown in Table 1.

The total solute concentration of the fixed first solution was 15 wt%, and the molar ratio of lead iodide (PbI ₂ ) and methylamine iodine (CH ₃ NH ₃ I) was changed to 1:0.8, 1:0.9, 1:1, respectively. 1:1.1 and 1:1.2, and the annealing temperature in the subsequent spraying process (as shown in the table) was fixed for 30 minutes. The formulation is shown in Table 2.

The total solute concentration of the fixed first solution was 15 wt%, and the molar ratio of fixed lead iodide (PbI ₂ ) and methylamine iodine (CH ₃ NH ₃ I) was 1:1, and the solvent dimethyl sulfoxide (DMSO) was changed. And γ-butyrolactone (GBL) mixed volume ratio of 10:0, 7; 3, 5:5, 3:7 and 0:10, and fixed annealing temperature in the subsequent spraying process (as shown in the table) For 30 minutes, the formulation is shown in Table 3.

Second solution configuration

In a preferred embodiment, the solute of the second solution of the present invention is lead iodide (PbI ₂ ), and the solvent comprises dimethylformamide (DMF) and dimethylarsine (DMSO). In order to further test the preferred formulation, different solute concentrations and different solvent volume ratio formulations were separately formulated.

Different concentrations of lead iodide solution were prepared, and the weight percentages thereof were 9 wt%, 11 wt%, 13 wt%, and 15 wt%, respectively. The formulation of the two solutions is shown in Table 4.

The concentration of the solute lead iodide fixed in the second solution is 11 wt%, and the mixing volume ratio of the adjusting solvent DMF:DMSO is 0:10, 3:7, 5:5, 7:3 and 10:0, and the formulation thereof is shown in Table 5. Shown.

Third solution configuration

Embodiment, the solute amine based methyl iodide (CH ₃ NH ₃ I) a third solution, the solvent-based dry isopropanol (IPA) in a preferred embodiment. In order to obtain a preferred formulation, a third solution of different concentrations was set for testing. The weight percentages of the methylamine iodine solution were 0.5 wt%, 1 wt%, 2 wt%, and 3 wt%, respectively, and the formulations are shown in Table 6.

I. First embodiment - one step of the perovskite film

The first embodiment uses a one-step method to produce a perovskite film, that is, spraying the first solution to form a perovskite film, and the manufacturing method comprises the following steps:

The first solution completed in the foregoing configuration is transferred into an ultrasonic system (power: 0.2 kW; frequency: 80 kHz), and the first solution is injected and fixed by a peristaltic force, the flow rate is 40 mL/hr, and the ultrasonic atomizer is turned on to be stabilized. The transfer gas valve is opened, and a low-pressure nitrogen gas of 0.01 atm is introduced, and the atomized first solution is brought to a substrate having a temperature of 70 ° C and a relative humidity of 40-55%, and the moving speed of the fixed spray gun is 2 cm/sec, and the nozzle height is set. 4cm, the first solution is sprayed, and the sprayed substrate is moved into a glove box for thermal annealing treatment, and heated at 100 ° C for 30 minutes, wherein the water oxygen value of the nitrogen controlled environment is less than 0.1 ppm to form calcium titanium. Mineral film and growth of the grain of the perovskite film.

II. Second Embodiment - Two-Step Manufacturing Method of Perovskite Film

The second embodiment uses a two-step method to prepare a perovskite film by spraying the second solution potassium iodide to form a film, and then spraying the third solution methylamine iodine to form a perovskite film, and the preparation method thereof Contains the following steps:

After the second solution prepared by the foregoing configuration is filtered through a pore size of 45 μm, it is transferred into an ultrasonic spraying system, and the second solution is injected and fixed by a peristaltic force, and the flow rate is 40 mL/hr, and the ultrasonic atomizer is turned on to be stabilized, and then turned on. The gas valve is sent to a low pressure nitrogen gas of 0.01 atm, and the atomized second solution is brought to the surface of the substrate at a temperature of 85 ° C. The moving speed of the fixed spray gun is 3 cm/sec and the nozzle height is 4 cm. The second solution is sprayed, and the sprayed second solution is deposited for about 5 seconds to form a second solution film layer.

Subsequently, the third solution completed in the foregoing configuration is moved into the ultrasonic system, and the third solution is injected and fixed by the creeping force, the flow rate is 40 mL/hr, and the ultrasonic atomizer is turned on to be stabilized, and the transfer gas valve is opened. The low-pressure nitrogen gas of 0.01 atm is introduced, and the atomized third solution is brought to the second solution film layer at a temperature of 45 ° C, the moving speed of the fixed spray gun is 1.5 cm/sec, and the nozzle height is 5 cm, and the second step is performed. The third solution is sprayed, and the sprayed substrate is moved to another 100 ° C hot plate for 2 minutes, wherein the relative humidity of the environment is controlled by nitrogen to be 35 ± 5% to form a perovskite film, and then moved to Heating in the glove box was continued at the same 100 ° C for 20 minutes to grow the crystal grains of the perovskite film.

III. Third Embodiment - Solar Cell Manufacturing Method Using First Embodiment

The perovskite solar cell of the present invention is a planar heterojunction structure, and the schematic diagram of the material of each layer and the three-dimensional schematic diagram of the structure are referred to FIG. 1 and FIG.

The third embodiment is a solar cell, wherein the active layer uses the first embodiment described above, and the manufacturing method comprises the following steps:

(a) spin coating a first carrier transport layer on a conductive substrate:

The conductive substrate 1 of the embodiment has a size of 15 mm×15 mm, ITO is used as the working electrode 12, and the glass is used as the bottom plate 11, and a 15 mm×5 mm ITO bottom electrode is etched on the surface of the substrate (see FIG. 3), and patterned. The surface modification method of the conductive substrate is not limited in the present invention. And in the order of detergent aqueous solution, deionized water, acetone, ethanol and other solvents, using ultrasonic cleaning machine in a variety of solvent environment for 15 minutes, to remove the surface of organic matter and dust by wet chemical immersion After that, it was dried with nitrogen. Then, the plasma cleaning machine is used to bombard the surface of the conductive substrate 1 by using a highly reactive molecule such as oxygen atoms and ozone molecules generated by atmospheric plasma for 5 minutes (using a power of 18 W), and the wet chemical immersion cannot be used. The chemically bonded organic material removed in a manner is physically and chemically removed, the surface of the conductive substrate 1 is restored to the original OH functional group, and the surface is rendered hydrophilic to facilitate deposition of the subsequent film. Next, the conductive substrate 1 was placed on a spin coater, and fine dust was blown off by a nitrogen gas gun, and the PEDOT:PSS solution was spin-coated at 5000 rpm for 35 seconds to form a PEDOT:PSS film having a thickness of about 30 nm. Then, the conductive substrate 1 was transferred to a heating plate 8 of 120 ° C for heat treatment for 20 minutes to remove residual solvent in the film formed by the PEDOT:PSS to form a first carrier transport layer 2.

(b) forming a perovskite film active layer on the first carrier transport layer using the method of the first embodiment:

The steps are the same as in the first embodiment. It should be noted that the substrate described in the first embodiment refers to the first carrier transfer layer 2 described above. Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer is obtained.

(c) vapor deposition to form a second carrier transport layer on the active layer of the perovskite film:

30 mg of C ₆₀ powder and 20 mg of BCP powder were placed on a tungsten boat and a quartz crucible in a thermal evaporation apparatus, and the structure of the above (b) was adhered to a vapor deposition plate and sent to a thermal evaporation plate. In the apparatus, when the degree of vacuum reaches 10 ^-6 torr or less, C ₆₀ to 20 nm is evaporated at a plating rate of 0.5 A/s to complete the preparation of the second carrier transfer layer 4. Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer / second carrier transport layer 4 is obtained.

(d) vapor deposition to form a hole barrier layer on the second carrier transfer layer:

Following the above evaporation process, switch to the hot coil system of the quartz crucible, heat the crucible to 100 ° C with a slow heating curve, and evaporate BCP to 7 nm at an evaporation rate of 0.4-0.6 A/s to complete the hole. Preparation of barrier layer 5. Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer / second carrier transport layer 4 / hole barrier layer 5 is obtained.

(e) vapor deposition to form an electrode layer on the hole barrier layer:

After the temperature of the chamber of the thermal evaporation apparatus is lowered to room temperature, the structure is taken out, and the material of the ITO patterned right side portion of about 3 mm is scraped off to expose the bottom electrode as the electrode layer 6 or the counter electrode (cathode ) Preparation area (Figure 6). The structure is adhered to the evaporation mask to scrape the pattern of the bare patterned ITO portion aligned with the short side electrode layer 6. Next, the silver ingot is placed on the tungsten boat of the thermal evaporation apparatus, and the structure to which the electrode layer 6 to be vapor-deposited is attached and the mask defining the area of the electrode layer 6 are placed in a thermal evaporation apparatus, to be vacuumed. When it reaches 10 ^-6 torr or less, the silver is vapor-deposited to 30 nm at a plating rate of 0.5 A/s, and then silver is evaporated to 100 nm at a plating rate of 1.0 A/s to complete the preparation of the electrode layer 6, and finally a conductive substrate 1 is obtained. / Structure of the first carrier transfer layer 2 / perovskite film 3 active layer / second carrier transport layer 4 / hole barrier layer 5 / electrode layer 6. The structure comprises 5 batteries, and the real active area of the perovskite solar cell is calculated as the area of the bottom layer ITO patterned and vapor-deposited electrode layer 6 silver interlaced to 5 mm × 2 mm (Fig. 7).

IV. Fourth Embodiment - Solar Cell Manufacturing Method Using Second Embodiment

The perovskite solar cell of the present invention is a planar heterojunction structure, and the schematic diagram of the material of each layer and the three-dimensional schematic diagram of the structure are referred to FIG. 1 and FIG.

The fourth embodiment is a solar cell, wherein the active layer uses the second embodiment described above, and the manufacturing method comprises the following steps:

(a) spin coating a first carrier transport layer on a conductive substrate:

The conductive substrate 1 of the embodiment has a size of 15 mm×15 mm, ITO is used as the working electrode 12, and the glass is used as the bottom plate 11, and a 15 mm×5 mm ITO bottom electrode is etched on the surface of the substrate (see FIG. 3), and patterned. The surface modification method of the conductive substrate is not limited in the present invention. And in the order of detergent aqueous solution, distilled water, acetone, isopropyl alcohol and other solvents, using ultrasonic cleaning machine in a variety of solvent environment for 5 minutes, to remove the surface of organic matter and dust by wet chemical immersion After that, it was dried with nitrogen. Then, the plasma cleaning machine is used to bombard the surface of the conductive substrate 1 by using a highly reactive molecule such as oxygen atoms and ozone molecules generated by atmospheric plasma for 5 minutes (using a power of 18 W), and the wet chemical immersion cannot be used. The chemically bonded organic material removed in a manner is physically and chemically removed, the surface of the conductive substrate 1 is restored to the original OH functional group, and the surface is rendered hydrophilic to facilitate deposition of the subsequent film. Next, the conductive substrate 1 was placed on a spin coater, and fine dust was blown off by a nitrogen gas gun, and 85 μL of a PEDOT:PSS solution filtered through a pore size of 45 μm was taken up by a micropipette to be dropped on the conductive substrate 1. After spin coating at 5000 rpm for 30 seconds, the conductive substrate 1 was transferred to a heating plate 8 of 120 ° C for heat treatment for 20 minutes to remove residual solvent in the film formed by the PEDOT:PSS to form a first load. Subtransport layer 2.

(b) forming a perovskite film active layer on the first carrier transport layer using the method of the second embodiment:

The steps are the same as the second embodiment. It should be noted that, in the first step described in the second embodiment, the substrate refers to the first carrier transfer layer 2, and the direction of the spray of the ultrasonic atomizer 7 is noted with the ITO. The longer side vertical center point of the pattern is passed (as shown in FIG. 4); and in the second step of the second embodiment, the third solution is sprayed a total of 3 times, because the overlapping width of the spraying path is about 2 cm. Covers the overall component area and notes that the direction in which the gun moves is parallel to the longer side of the ITO patterning (Figure 5). Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer is obtained.

(c) vapor deposition to form a second carrier transport layer on the active layer of the perovskite film:

30 mg of C ₆₀ powder and 20 mg of BCP powder were placed on a tungsten boat and a quartz crucible in a thermal evaporation apparatus, and the structure of the above (b) was adhered to a vapor deposition plate and sent to a thermal evaporation plate. In the apparatus, when the degree of vacuum reaches 4×10 −6 torr or less, C ₆₀ is evaporated to 30 nm at a plating rate of 0.5 A/s to complete the preparation of the second carrier transfer layer 4 . Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer / second carrier transport layer 4 is obtained.

(d) vapor deposition to form a hole barrier layer on the second carrier transfer layer:

Following the above evaporation process, switch to the hot coil system of the quartz crucible, heat the crucible to 100 ° C with a slow heating curve, and evaporate BCP to 7 nm at an evaporation rate of 0.4-0.6 A/s to complete the hole. Preparation of barrier layer 5. Finally, a structure of a conductive substrate 1 / first carrier transport layer 2 / perovskite film 3 active layer / second carrier transport layer 4 / hole barrier layer 5 is obtained.

(e) vapor deposition to form an electrode layer on the hole barrier layer:

After the temperature of the chamber of the thermal evaporation apparatus is lowered to room temperature, the structure is taken out, and the material of the ITO patterned right side portion of about 3 mm is scraped off to expose the bottom electrode as the electrode layer 6 or the counter electrode (cathode). ) Preparation area (Figure 6). The structure is adhered to the evaporation mask to scrape the pattern of the bare patterned ITO portion aligned with the short side electrode layer 6. Next, the silver ingot is placed on the tungsten boat of the thermal evaporation apparatus, and the structure to which the electrode layer 6 to be vapor-deposited is attached and the mask defining the area of the electrode layer 6 are placed in a thermal evaporation apparatus, to be vacuumed. When it reaches 4×10-6 torr or less, the silver is vapor-deposited to 30 nm at a plating rate of 0.5 A/s, and silver is evaporated to 100 nm at a plating rate of 1.0 A/s to complete the preparation of the electrode layer 6, thereby finally obtaining a conductive substrate. 1/ The structure of the first carrier transfer layer 2 / perovskite film 3 active layer / second carrier transport layer 4 / hole barrier layer 5 / electrode layer 6. The structure comprises 5 batteries, and the real active area of the perovskite solar cell is calculated as the area of the bottom layer ITO patterned and vapor-deposited electrode layer 6 silver interlaced to 5 mm × 2 mm (Fig. 7).

[Example 1] - Effect of first solution concentration (Table 1) on solar cells

Referring to Figures 8(a) to (d), the first solution is used as a raw material of the perovskite film of the first embodiment of the present invention and the solar cell of the third embodiment, and the concentration thereof affects the perovskite film. The thickness was tested in the first solution formula table of Table 1. With the other parameters being the same, the higher the concentration of the first solution, the higher the thickness of the formed perovskite film. Referring to FIG. 8(c), in a preferred embodiment, the first solution forms a perovskite film of CH ₃ NH ₃ Pbl ₃ film, and the absorption spectrum starts at a wavelength of about 785 nm (1.58 eV). A broadband is observed near the near-infrared light to the visible region. In addition, the intensity of the absorbance is significantly enhanced by the increase in the concentration of the first solution, mainly because the thicker perovskite film absorbs more light.

8(d) is a graph showing current density-voltage (JV) curves of different concentrations of the first solution according to the third embodiment of the present invention, that is, current density-voltage (JV) curves of different perovskite film thickness solar cells. . Wherein, the first solution has a total concentration of 9 wt% of a perovskite film having a thickness of about 200 nm, which exhibits a lower average PCE value of 4.07 ± 1.28%. Conversely, the first solution has a total concentration of 15 wt% of a perovskite film having a thickness of about 450 nm, which exhibits the best performance under the test conditions of Example 1, and has a PCE value of 11.30% and a short-circuit current density (Jsc) of 19.7 mA/cm2, the open loop voltage (Voc) was 0.78 V, and the fill factor (FF) was 73.6%. The results of solar cell performance performance corresponding to the first solution concentration of Table 1 are shown in Table 7.

Referring to Fig. 8(b), the XRD peak of the third embodiment of the present invention is at 19.8° and 40.5°, and exhibits strong CH ₃ NH at (112)/(200) and (224)/(400), respectively. ₃ Pbl ₃ crystal plane. A weak peak at 12.5° indicates that the perovskite film contains Pbl ₂ impurities. In addition, the peak intensity of XRD increases as the thickness of the perovskite film increases.

Referring to Fig. 8(a), SEM micrographs of the perovskite film of different thicknesses indicate that they have a similar flower crystal structure but different grain sizes. It is apparent that the occurrence of smaller crystal grains of about 50 μm in the crystallization of the 9 wt% first solution of the perovskite film allows the gap region to have an overall bulk defect density. In this case, the lowest PCE of the thinner perovskite film confirms its structural and optical properties, and mainly comes from a low contribution of light absorption, and insufficient charge transfer between incomplete surface and low crystallinity. Thus, the 15 wt% first solution has a perovskite film thickness of about 450 nm, which has larger grains to reduce charge recombination at grain boundaries and significantly improve fill factor and open loop voltage.

[Example 2] - Effect of the ratio of the first solution solute (Table 2) on the solar cell

Referring to Figures 9(a) to (d), for perovskite solar cell components, the thickness of the active layer of the perovskite film is critical, and the perovskite carrier has a long transmission life and a distance of up to a micron level. The light usability of the element can be increased by increasing the thickness, but if it exceeds the appropriate thickness, the stacking and roughness of the perovskite crystal rises, resulting in a decrease in photoelectric efficiency.

The formulation of the perovskite film precursor, in this embodiment, is the formulation of the first solution solute (Table 2), which is closely related to the quality of the produced perovskite film and the PCE performance of the solar cell using the same. The association. Figure 9 (a) shows the SEM image, revealing the morphology of the perovskite film in the solute lead iodide: methylamine iodine from 1:0.8, 1:0.9 to 1:1, respectively. The shape changes to a needle/flower-like mixture and a flower shape. If the molar ratio is further reduced to less than 1:1, the flower-like pattern with a ring-shaped domain is maintained, however, when the molar ratio is reduced to 1:1.2, The average grain size continues to decrease and the surface becomes rougher. When the solute molar ratio of the perovskite film is 1:1, the gap between the crystal grains is clearly lowered, and the dispersion of the perovskite film can be found to be considerably reduced and the uniformity is improved, and the optical absorbance can be enhanced ( As shown in Fig. 9(c)), it contributes to the improvement of light capturing ability.

Regarding the XRD analysis (Fig. 9(b)), when the solute ratio exceeds 1:1, a lead iodide diffraction peak appears at 2θ=12.5°, which is shown to exist in the perovskite film of CH ₃ NH ₃ Pbl ₃ . Unreacted lead iodide crystal impurities. The XRD pattern of the solute ratio from 1:0.8 to 1:1.2 shows a decrease in the strength of the perovskite film at 2θ = 14.1° (representing the (110) and (220) planes), and a strong (112)/(220) And the CH ₃ NH ₃ Pbl ₃ crystal plane of (224)/(440), which means that the orientation of the crystal is related to the membrane type manipulated by the composition of the changing precursor (this is the solute of the first solution) ( Needle or flower shape).

Through the above analysis, a flower-like perovskite film crystal having a large crystal domain has a prerequisite for a high-efficiency photovoltaic device. The JV plots for the different precursor ratios are shown in Figure 9(d), and the photovoltaic performance is shown in Table 8. The results show that the use of an equimolar ratio of lead iodide: methylamine iodine as a light absorber of a solar cell exhibits a large crystalline domain and a crystalline orientation of (112)/(220) and (224)/(440), It contributes to the transfer of photogenerated carriers and increases the photocurrent and gives a better PCE value. The matrix coverage of the calculated precursor ratios of 1:1 and 1:1.2 was 98.3% and 87.2%, respectively, and therefore, the CH ₃ NH ₃ Pbl ₃ perovskite film precursor ratio of 1:1.2 gave a lower short-circuit current density ( J _SC ) and open-loop voltage (V _OC ) values are mainly due to incomplete coverage and large surface roughness. The crystal size and orientation change of the perovskite film caused by the ratio of different precursor formulations is a key factor that mainly affects the photoreaction efficiency.

[Example 3] - Effect of the ratio of the first solution solvent (Table 3) on the solar cell

Referring to Figures 10(a) to (d), in Example 3, the volume ratio of the mixed solvent was adjusted in the state where the fixed solute lead iodide: methylamine iodine ratio was 1:1 (as shown in Table 3), Fig. 10 (a) is a plan view showing an SEM image of the perovskite film of Example 3. All of the membranes exhibited similar perovskite crystal forms, and the scale of the flower-like crystallites ranged from tens to hundreds of micrometers depending on the proportion of the solvent composition.

Referring to Fig. 10(b), the crystal structure of the perovskite in different solvent mixing ratios forms the same pattern except for a slight diffraction intensity, and the strong peaks at 19.8° and 40.5° are confirmed by the XRD pattern. It directs the (112)/(220) and (112)/(220) planes. In the examples using pure GBL, the crystallite group of the perovskite is significantly smaller than the other solvent ratios, and therefore, many voids are observed at the crystal boundaries. That is, the coverage of perovskites is relatively low (only about 74.7%), which may result in deterioration of solar cell performance. In another embodiment, the addition of a small amount of DMSO (eg, DMSO: GBL = 3:7) to the GBL produces a reasonably uniform and dense CH ₃ NH ₃ Pbl ₃ crystal, exhibiting a sub-millimeter scale flower-like grain pattern. .

Referring to Figure 10(c), a preferred microstructure type can be obtained from a DMSO:GBL ratio of 5:5, although the perovskite film formed by pure GBL has a poor coverage and a decrease in absorption intensity, particularly in the low wavelength region ( 400-650 nm), however, the interconnection between large perovskite groups allows them to exhibit high light absorption over a wide range of visible and near-infrared light.

Referring to Fig. 10(d), which is a JV graph, the photoelectric efficacy of Example 3 is shown in Table 9. The results show that the preferred solvent mixing ratio is 5:5, which enhances the short-circuit current density (J _SC ) and the fill factor (FF), and improves the power conversion efficiency (PCE) compared to pure GBL and pure DMSO, respectively. 2 and 1.5 times.

[Example 4] - Effect of thermal annealing treatment conditions on the one-step perovskite film type and solar cell performance

Referring to Figures 11(a) to (d), in order to understand the effect of thermal annealing operating conditions on the perovskite film pattern and the performance of the solar cell using the same, the concentration of the first solution is fixed at 15 wt%, solute lead iodide and When the ratio of the amide to iodine molar ratio is 1:1 and the solvent DMSO:GBL volume ratio is 5:5, the thermal annealing temperatures are set to 90 ° C, 100 ° C, 110 ° C, 120 ° C and 130 ° C, respectively, and the treatment is continued 30 minute. The SEM image is shown in Figure 11(a), which shows that the morphology of the perovskite crystals formed by different thermal annealing conditions is significantly different. When the thermal annealing temperature is much lower than the boiling point of the mixed solvent (for example, below 90 ° C), an intermittent needle-like crystal domain appears on the surface of the film. In addition, it was also observed that when the thermal annealing temperature was increased to 100 ° C, the crystal form changed from acicular to flower-like, and when the thermal annealing temperature was further increased to over 110 ° C, it would be a large flower-like crystal domain with fewer grain boundaries. The composition is very different.

Fig. 11(c) is a view showing the ultraviolet/visible absorption spectrum of Example 4, which shows a typical absorption spectrum of a CH ₃ NH ₃ Pbl ₃ perovskite film. When the thermal annealing temperature was raised from 90 ° C to 110 ° C, the absorbance of the overall spectral range was significantly increased, and the further increase of the thermal annealing temperature showed a similar absorbance without significant change.

Figure 11 (b) shows the XRD pattern of Example 4, all of which are converted to perovskite film by thermal annealing, but the peaks of thermal annealing at 90 ° C and 100 ° C at 14.1 ° and 28.3 ° indicate CH ₃ NH, respectively. ₃ Pbl ₃ (110) and (220), although other planes have higher strength, especially (112)/200 and (224)/(400), indicating a better grain orientation at a thermal annealing temperature of over 110 °C Different and highly correlated with post annealing temperature. Most importantly, crystal plane differences can be interpreted as differential patterns. When the methylamine iodine/lead iodide/DMSO complex crystal is heated at a lower temperature, the composite will cure reasonably, and then the CH ₃ NH ₃ Pbl ₃ peak (100) at 14.1° will increase and form a tree. Type. The solvent is vaporized at elevated temperatures without the formation of intermediate complexes that affect the orientation of the CH ₃ NH ₃ Pbl ₃ grains formed, and the flower-like pattern is strengthened along the (112) and (200) orientations. Or development. In this case (thermal annealing temperature 110 ° C), a finished product of an inverse plane perovskite solar cell having an ITO/PEDOT:PSS/CH ₃ NH ₃ Pbl ₃ /C ₆₀ /BCP/Ag structure, the cross-sectional SEM image showing about 450 nm The thick CH ₃ NH ₃ Pbl ₃ dense layer has a narrower grain boundary.

Referring to Fig. 11(d), which is a J-V graph, the photoelectric efficacy of Example 4 is shown in Table 10. Comparing the different thermal annealing procedures, it is preferred to use a heating temperature of 110 ° C, which exhibits a PCE of 11.30% and a high F.F. of 73.6%, possibly due to the formation of a highly directional large flower-like perovskite crystal.

[Example 5] - Effect of second solution concentration (Table 4) on solar cells

Referring to Figures 12(a) to (d), the film is sprayed to form a film according to the formulation of Table 4. As described above, the active layer thickness of the perovskite film is closely related to the photoelectric efficacy of the solar cell, and is a two-step process. It is said that the first layer of the lead iodide thin film layer (i.e., the second solution film layer) has a significant influence on the thickness of the perovskite film formed by the reaction of the post-layered methylamine iodine. Referring to Fig. 12(a), the SEM measurement results show that whether the thickness of the lead iodide layer or the thickness of the perovskite film is positively correlated with the concentration of lead iodide, that is, when the concentration of lead iodide is increased, A thick lead iodide film is further reacted to obtain a thicker perovskite film.

For solar cells, the absorption spectrum can represent the availability of light, and the stronger the range of light absorption, the larger the range, the more excitons can be expected to be generated. Referring to Fig. 12(c), there is shown an absorption spectrum of a perovskite film produced by different concentrations of lead iodide. In general, the thicker the film thickness in the appropriate range, the stronger the light absorption, and the appropriate range of such perovskite materials is about 300 nm to 600 nm.

Referring to Figure 12(b), Example 5 reacted with different concentrations of lead iodide (formulation of Table 4) and fixed methyl iodide concentration (1 wt%) and spray amount, and the results showed higher concentrations such as 13 wt% and 15 wt. % does not improve the light absorption capacity, and XRD analysis shows that the residual amount of lead iodide is quite high, so the unreacted lead iodide residue is too much, even if the thickness is within a reasonable range, the increase of lead iodide concentration does not help. Increased light absorption capacity.

The above-mentioned perovskite film was made into a solar cell and subjected to energy measurement. The J-V curve is shown in Fig. 12(d), and the data is organized as shown in Table 11. The results show that the concentration of lead iodide 11wt% has a relatively high light absorption capacity and short-circuit current density, and as the concentration of lead iodide is increased to 13wt% and 15wt%, residual unconverted lead iodide will lead to partial carrier of the whole component. There is a problem with the transmission, which leads to a decrease in the short-circuit current density value. The high residual lead iodide can also be regarded as the internal impedance of the component. If the impedance is too high, the fill factor value will also decrease, which is the main reason for the low efficiency of the overall component.

[Example 6] - Effect of solvent ratio of second solution (Table 5) on solar cells

Referring to Figures 13(a) to (d), DMF has a relatively low boiling point (154 ° C). However, in one embodiment, it is found that the surface morphology of the film formed by single DMF spraying is not uniform, possibly due to solvent. The evaporation rate is too fast, so in another preferred embodiment, the mixed solvent is used to mix DMF and DMSO in different ratios of 0:10, 3:7, 5:5, 7:3 and 10:0. And dissolved into 11 wt% lead iodide solution (formulation of Table 5). Since the boiling point of DMSO (189 ° C) is higher than that of DMF, it is observed that the wet film after spraying has a light yellow film formed slowly, and then the solvent is completely evaporated to obtain uniform and complete thickness. The quality of lead iodide film does not change much.

Referring to the SEM surface map of Fig. 13(a), it can be found that the crystal grains of the perovskite film produced by DMF:DMSO=0:10, 3:7 and 7:3 are not completely covered, and some pores still exist. Although DMF: DMSO is 3:7, it can get crystals of 700 to 800 nm or more, which is much larger than the best 5:5. However, the barrier caused by the grain boundary may hinder the carrier transfer, so that the battery efficiency is not good. Do your best. The film prepared by DMF:DMSO at 10:0 did not differ much from DMF:DMSO at 5:5 under the observation of larger magnification, but the field of view was enlarged, and the overall film morphology was widely observed. In many places, the coverage is not very complete, and there are even some unreacted lead iodide morphology, which may lead to a decrease in battery efficiency.

Referring to Figure 13(b), which shows the absorption spectrum, the results show that DMF: DMSO has a higher light absorption at 5:5, especially in the wavelength range of 550 nm to 750 nm, and this wavelength is also a perovskite. The main absorption of visible light wavelength position is enough to explain one of the reasons for its high short-circuit current.

The above-mentioned perovskite film was made into a solar cell and subjected to energy measurement. The J-V curve is shown in Fig. 13(c), and the data is organized as shown in Table 12. The results show that the solvent ratio of 5:5 still has a relatively high photocurrent output, and also because the coverage and crystal stack tightness are also better, so the open-loop voltage and fill factor values are compared to other ratios. The components were much higher, so the results of Example 6 showed that the solvent DMF of the second solution: DMSO was 5:5, a preferred ratio.

[Example 7] - Effect of third solution concentration (Table 6) on solar cells

Referring to Figures 14(a) to (d), in the above embodiment, a preferred embodiment is based on a lead iodide concentration of 11 wt%, a lead iodide solvent DMF: DMSO of 5:5 and a methylamine iodine concentration of At 1wt%, a relatively close, high surface film coverage and a thickness of about 408nm perovskite film can be obtained. However, the XRD pattern (Fig. 12(b)) is 12.6° at the corresponding position of 2 θ of lead iodide. The analysis showed that there was still some unreacted lead iodide residue, so the experiment of Example 7 adjusted the methylamine iodine concentrations to 0.5 wt%, 1 wt%, 2 wt% and 3 wt%, respectively (formulation of Table 6) to obtain complete lead iodide. Reaction of the perovskite film.

Referring to Figure 14(b), there is shown a perovskite film XRD prepared by methylamine iodine concentration of 0.5 wt%, 1 wt%, 2 wt%, and 3 wt%. The results showed that the perovskite film prepared by methylamine iodine concentration of 2wt% and 3wt% had no residual lead iodide at 12.6°. However, the signal of methylamine iodine appeared at 9.8° and 19.6°, indicating methylamine. Iodine has been sprayed in excess. In addition, XRD has also detected intermediates of lead iodide and DMSO. Excess methylamine iodine and intermediates may cause a decrease in battery performance.

Referring to Figure 14(d), it is shown as a UV-Vis map. The results show that the main absorption band of the perovskite film is 550nm to 800nm. It can be observed that the methylamine iodine concentration is 1wt% relative to the residual amount of lead iodide, and the methylamine iodine concentration is lower than the residual amount of lead iodide 2wt. % The light absorption in this band is higher, probably due to the relative increase in perovskite concentration. However, lead iodide absorbs shorter wavelength visible light (below 550 nm), so some lead iodide remains in the perovskite film to facilitate absorption of shorter wavelength visible light.

Referring to Figure 14 (a), there is shown a SEM image of the perovskite surface of Example 7. The results show that the finished perovskite film made of 0.5wt% methylamine iodine has no compact structure on the surface, and even there are fine flat round unreacted lead iodide crystal residues. This result is also related to the XRD pattern (Fig. 14). (b)) Match. In contrast, the perovskite film produced by using 1 wt% methylamine iodine has high quality, compact structure and high coverage. Then increase the concentration to 2wt% methylamine iodine, which produces larger perovskite grains, but in some perovskite surface areas, methylamine iodine crystal precipitation can be observed, that is, methylamine iodine has been Excessive spraying. If the methylamine iodine concentration is increased to 3 wt%, the crystallization is more serious, and the surface morphology of the original perovskite is hardly observed.

When the battery element is fabricated, the battery having a methylamine iodine concentration of 2% by weight and 3% by weight may be similarly reduced in the vicinity of the electrode after about 5 to 10 minutes after the evaporation of the silver electrode, and the film may be degraded after being left for a long time. However, this phenomenon is rarely observed at a methylamine iodine concentration of 0.5 wt% and 1 wt%. This phenomenon may be due to excessive methylamine iodine remaining on the surface, so that moisture in the air penetrates into the active layer of the perovskite film through defects. Under the action of water molecules, iodine precipitation in methylamine iodine or perovskite may be initiated, causing iodine exudation to chemically react with silver to form silver iodide, and the color of lead iodide after deuterated silver iodide and perovskite is similar. Yellow system. On the other hand, in the solar cell produced by the methylamine iodine concentration of 2 wt% and 3 wt%, the active layer was depleted very rapidly, so that the photovoltaic efficiency comparison of Example 7 could not be performed.

In order to improve the problem of lead iodide residue, a perovskite film was prepared by selecting a methylamine iodine concentration of 1.5 wt%, and the XRD analysis thereof is shown in Fig. 14(c). The results were similar to those of the methylamine iodine concentration of 2% by weight. Although the residual amount of lead iodide was decreased a lot, the signals of methylamine iodine and lead iodide-DMSO intermediates were detected. In addition, a small portion of lead iodide may change the energy level structure, which will increase the open circuit voltage slightly, and some residual lead iodide layer can be used as an electron blocking layer for the fabrication of pin batteries (ie, the deposition sequence is first deposited). The hole transfer layer) can block the electrons from passing down and recombining with the holes, but too much lead iodide will increase the resistance, shorten the life of the carriers, and reduce the photoelectric conversion efficiency.

[Example 8] - Effect of thermal annealing treatment conditions on the two-step perovskite film type and solar cell performance

In the eighth embodiment, the thermal annealing treatment conditions are adjusted, and the influences on the grain growth and arrangement of the perovskite film formed by the two-step method are discussed below, respectively, for different thermal annealing temperatures and thermal annealing times:

The first step is to discuss the effect of thermal annealing temperature. Referring to Figure 15 (a) to (e), the thermal annealing temperature mainly affects the surface morphology and molecular arrangement of the perovskite film, and the film is controlled by the treatment of thermal energy. The arrangement between the grains is more tight or increased, and the like. In general, the thermal annealing temperature of the above-mentioned organic-inorganic CH ₃ NH ₃ PbI ₃ perovskite film is usually between 90 ° C and 120 ° C, if it is a group A molecule with a larger ionic radius, for example. :FAI, the thermal annealing temperature will increase to 140 °C. In this example, the change of the perovskite film was investigated under the same heating temperature (90 ° C to 120 ° C) for 20 minutes.

Referring to Figure 15 (a), there is shown a SEM image of the surface of the perovskite film. The results show that the structure of the perovskite film treated at 90 °C is loose and not tight, which may cause the carrier to be unsmooth in the process of transmission and also cause a decrease in the F.F. value. When the heat treatment temperature is raised to 110 °C, the phenomenon of perovskite degradation occurs in some areas (as shown in Figure 15 (a)), and then raised to a higher 120 °C is more serious, almost all degraded into iodine. The fine flat round crystal grains of lead, but the overall thickness of the SEM cross-sectional structure (Fig. 15(e)) is maintained at 400 ± 17 nm, with little difference.

Referring to Figure 15(b), there is shown an XRD pattern of the perovskite film structure of Example 8. The results show that when the thermal annealing temperature is too low (such as 90 ° C), there will be excessive lead iodide. It is speculated that as the heat treatment temperature increases, the methylamine iodine just sprayed and the lead iodide react. The perovskite is formed. The thermal annealing temperature is 100 °C, and a better condition and structure can be obtained. After the temperature is further increased to 110 ° C, the peak of lead iodide which is originally located at 12.6 ° can be found to rise, echoing the SEM image results, perovskite Because the heat treatment temperature is too high to degrade into lead iodide, a significant peak of lead iodide can be observed at a thermal annealing temperature of 120 ° C, indicating that the degree of degradation of the perovskite is quite high, which leads to a decrease in the efficiency of the element.

Referring to Fig. 15(e), there is shown a perovskite UV-Vis absorption spectrum of Example 8. The results show that the thermal annealing temperature of 100 ° C still has a relatively high light absorption performance, and the light absorption performance decreases with the increase of temperature, because the film begins to degrade into lead iodide when the temperature rises, and the unreacted 90 ° C film And the 120 ° C perovskite film with excessive degradation is the worst light absorption performance.

The above-mentioned perovskite film was made into a solar cell and subjected to energy measurement. The J-V curve is shown in Fig. 15(d), and the data is organized as shown in Table 13. The results show that when the temperature reaches 100 °C, there is a relatively high efficiency performance, but when the temperature continues to rise, the short-circuit current and FF have a tendency to decrease, which may be caused by the occurrence of the aforementioned lead iodide, and the photoelectric parameter of 90 °C. Similar to 120 °C, the thin film XRD identification analysis has too much lead iodide structure, low absorption, and low short-circuit current.

The second part discusses the effect of thermal annealing time on the perovskite film. Referring to Figures 16(a) to (c), the thermal annealing process time is 0, 20, respectively, at a fixed thermal annealing temperature of 100 °C. 40, 60 minutes of change.

Referring to Figure 16(a), there is shown an XRD pattern of a perovskite film of different thermal annealing times. The results show that when there is no thermal annealing treatment, only after the spray of methylamine iodine is sprayed into perovskite, the peak of residual lead iodide and methylamine iodine is observed, but if it is annealed to 20 minutes. After that, the peak of methylamine iodine disappeared, and it may be that the methylamine iodine which was just sprayed did not fully react with the lead iodide substrate without thermal annealing treatment. When the thermal annealing time is raised to 40 minutes and 60 minutes, the peak of lead iodide can be clearly observed from the XRD pattern, indicating that the perovskite film is reduced and degraded, which may be caused by too long heating time.

Referring to Figure 16(b), there is shown a UV-Vis absorption spectrum of a perovskite film of different thermal annealing times. The results show that the light absorption at 20 minutes of annealing time is much higher than that at 40 minutes and 60 minutes, and 40 minutes is higher than 60 minutes. This trend indicates that the length of heating time is positively correlated with the degree of degradation of perovskite film. It also echoes the results of XRD. The perovskite film absorption without thermal annealing is the lowest.

The above-mentioned perovskite film was made into a solar cell and subjected to energy measurement. The J-V curve is shown in Fig. 16(c), and the data is as shown in Table 14. The results show that the short-circuit current, open-circuit voltage and fill factor increase due to thermal annealing. The highest efficiency is achieved at 20 minutes, and when the time is increased to 40 minutes, the open circuit voltage and fill factor do not drop too much. However, the short-circuit current is significantly reduced, which may also be related to the appearance of lead iodide. When heated for another 60 minutes, the current performance is further reduced to a little better than the perovskite film without thermal annealing, and the open circuit voltage and fill factor are both Falling a lot. From this, it can be known that the thermal annealing time has a relatively high efficiency performance at 20 minutes.

By adjusting the precursor concentration, the solvent ratio, and the thermal annealing treatment conditions to control the thickness and morphology of the perovskite film, the power of the solar cell prepared by the one-step method according to the third embodiment of the present invention is adjusted after the optimal condition parameters. The conversion efficiency (PCE) was 11.3%, the short-circuit current density (J _SC ) was 19.7 mA/cm ² , the open-loop voltage (V _OC ) was 0.78 V, and the fill factor (FF) was 73.6%, and was measured by spectroscopic spectrometry. The external quantum efficiency is 80%; the solar cell produced by the second method using the two-step method shows a power conversion efficiency (PCE) of 10.1%, a short-circuit current density (J _SC ) of 18.8 mA/cm ² , and an open-loop voltage. (V _OC ) is 0.78 V and the fill factor (FF) is 68.5%. Both power generation efficiencies have reached commercial standards.

In summary, the present invention provides a method for fabricating a perovskite film and a solar cell using ultrasonic spraying technology, which uses a ultrasonic vibration technique to first refine the coating and then atomize the particles by spraying. The surface of the target object is formed into a film, and the invention has higher utilization of the spraying material than the prior art, and is relatively easy to realize large-area production, and can be connected with the roll-to-roll process, and the spraying effect is more detailed, and has The potential to produce large scale processes and low cost perovskite solar cells.

The invention has been described in detail above, but the foregoing is only a preferred embodiment of the invention, and is not intended to limit the scope of the invention, Variations and modifications are still within the scope of the patents of the present invention.

Claims (10)

 A method for preparing a perovskite film by ultrasonically spraying (1) a first solution to form a perovskite film on a substrate; or (2) forming a second solution on a substrate, A third solution is sprayed onto the film formed by the second solution to form a perovskite film.   The method for producing a perovskite film according to claim 1, wherein the solute of the first solution is BX ₂ and AX, wherein A is an organic cation, B is a metal cation and X is a halogen group, and the BX ₂ And AX, the molar ratio is 1:0.8 to 1:1.2.  The method for producing a perovskite film according to claim 1 or 2, wherein the solvent of the first solution is dimethyl hydrazine (DMSO) and γ-butyrolactone (GBL), and the mixing volume ratio thereof is 10 : 0 to 3: 7.   The method for producing a perovskite film according to claim 1, wherein the solute of the second solution is BX ₂ , wherein B is a metal cation and X is a halogen group; and the solvent of the second solution comprises dimethyl group Formamide (DMF) and dimethyl hydrazine (DMSO) have a mixed volume ratio of 10:0 to 3:7.  The perovskite film according to claim 1 or 4, wherein the solute of the third solution is AX, wherein A is an organic cation and X is a halogen group, and the solvent of the third solution is isopropyl alcohol.    A method of fabricating a solar cell, the method comprising: (a) spin coating a first carrier transport layer on a conductive substrate; (b) forming a calcium titanium using the method of any one of claims 1 to 5. a thin film active layer on the first carrier transport layer; (c) vapor deposition to form a second carrier transport layer on the active layer of the perovskite film; (d) vapor deposition to form a hole barrier layer And (e) vapor deposition to form an electrode layer on the hole blocking layer.   The method for fabricating a solar cell according to claim 6, wherein the conductive substrate is selected from the group consisting of fluorine doped tin oxide (FTO), indium tin oxide (ITO), and ZnO-Ga _{2 .} A group consisting of O ₃ , ZnO-Al ₂ O ₃ , tin oxide, and zinc oxide. The method for fabricating a solar cell according to claim 6, wherein the first carrier transfer layer is a hole transfer layer, and the material thereof is selected from the group consisting of 2, 2', 7, 7'-four-(N, N -di-p-methoxyphenethylamine) 9,9 spiro-OMeTAD, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), N, N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD) and polytrihexyl polythiophene ( a group consisting of P3HT); the second carrier transport layer is an electron transport layer, the material of which comprises carbon-60 (C ₆₀ ), ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid ester.  The method for fabricating a solar cell according to claim 6, wherein the material of the hole barrier layer comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 1,3,5-tris(4-pyridin-3-ylbenzene Benzene (1,3,5-tri(p-pyrid-3-yl-phenyl)benzene, TpPyPB) or diphenyl bis[4-(pyridin-3-yl)phenyl]decane (diphenyl bis (4) -(pyridin-3-yl)phenyl)silane, DPPS).    The method for fabricating a solar cell according to any one of claims 6 to 9, wherein the electrode layer is a counter electrode layer, and the material of the counter electrode layer is selected from the group consisting of copper, gold, silver, rhodium, palladium, nickel, A group of molybdenum, aluminum, alloys thereof, and multilayer materials comprising the same.