CN111384243B

CN111384243B - Perovskite solar cell and method for manufacturing same

Info

Publication number: CN111384243B
Application number: CN201910096554.9A
Authority: CN
Inventors: 徐为哲; 许弘儒; 王凯正
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2018-12-27
Filing date: 2019-01-30
Publication date: 2023-06-30
Anticipated expiration: 2039-01-30
Also published as: TWI692879B; CN111384243A; TW202025505A

Abstract

A perovskite solar cell. The perovskite solar cell comprises a substrate, a first semiconductor layer arranged on the substrate, an induction crystal nucleus layer arranged on the first semiconductor layer, a perovskite absorption layer covering the induction crystal nucleus layer and the first semiconductor layer, a second semiconductor layer arranged on the perovskite absorption layer and an electrode layer arranged on the second semiconductor layer. The present invention also provides a method for producing the perovskite solar cell.

Description

Perovskite solar cell and method for manufacturing same

Technical Field

The present invention relates to perovskite solar cells, and in particular to perovskite solar cells comprising an induced nucleation layer.

Background

In recent years, the solar photovoltaic industry is promoted to be vigorously developed due to the influence of global climate change, environmental pollution and gradual shortage of resources and under the warning of high environmental awareness and energy crisis. The power generation principle of the solar cell is to convert light energy into electric energy by using the photoelectric effect of semiconductor materials. Specifically, when light is irradiated to the semiconductor material, photons are generated, and the photons generate electron-hole pairs inside the semiconductor material, and then, the electrons and the holes are respectively transported to two opposite electrodes by an internal electric field, thereby generating a voltage. At this time, if the two electrodes are connected to an external circuit, a current is generated.

Currently, an emerging semiconductor material with a perovskite (perovskie) structure is proposed, which has the advantages of high photoelectric conversion efficiency, low preparation cost and the like, and is not easy to cause pollution. Therefore, research techniques for applying perovskite materials to solar cells are growing. However, the biggest problem facing the current application is poor stability of solar cells on perovskite.

Therefore, there is a need to improve the stability of perovskite absorber layers to enhance their applicability.

Disclosure of Invention

The invention provides a perovskite solar cell. The perovskite solar cell structure comprises: the semiconductor device comprises a substrate, a first semiconductor layer, an induction crystal nucleus layer, a perovskite absorption layer, a second semiconductor layer, an electrode layer and an electrode layer, wherein the substrate is arranged on the substrate, the induction crystal nucleus layer is arranged on the first semiconductor layer, the perovskite absorption layer covers the induction crystal nucleus layer, the first semiconductor layer and the second semiconductor layer, the electrode layer is arranged on the perovskite absorption layer, the second semiconductor layer is arranged on the second semiconductor layer, and the electrode layer is arranged on the second semiconductor layer.

The present invention also provides a method for producing the perovskite solar cell. The method includes providing a substrate and forming a first semiconductor layer on the substrate, forming an induced nucleation layer on the first semiconductor layer, forming a perovskite absorber layer to cover the induced nucleation layer and the first semiconductor layer, forming a second semiconductor layer on the perovskite absorber layer, and forming an electrode layer on the second semiconductor layer.

In order to make the features and advantages of the embodiments of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1 is a schematic cross-sectional view of a perovskite solar cell structure according to some embodiments of the invention;

FIG. 2 is a top view of a perovskite solar cell structure according to some embodiments of the invention;

3A-3D are process flow diagrams of intermediate structures forming perovskite solar cell structures according to some embodiments of the invention;

FIGS. 4A-4B are process flow diagrams of intermediate structures forming perovskite solar cell structures according to some embodiments of the invention;

FIGS. 5A-5D are enlarged views of the perovskite absorber layer shown by an optical microscope, wherein FIGS. 5A, 5B are enlarged views of the perovskite absorber layer of the comparative example, and FIGS. 5C, 5D are enlarged views of the perovskite absorber layer of the embodiment;

FIGS. 6A, 6B are enlarged views of perovskite absorber layers of some embodiments of the invention as shown by scanning electron microscopy;

FIG. 7 is a graph of fluorescence spectra of light excitation of perovskite absorption layers of comparative and example;

FIG. 8 is an X-ray diffraction analysis spectrum of the perovskite absorption layers of the comparative examples and examples; and

fig. 9 is a graph of open cell voltage versus current density for the perovskite solar cell structures of the comparative examples and examples.

[ reference numerals description ]

100. Perovskite solar cell structure

110. Substrate board

120. First semiconductor layer

130. Induced nucleation layer

130a nucleation sites

130b nucleation sites

140. Perovskite absorber layer

150. Second semiconductor layer

160. Transparent conductive layer

170. Electrode

180. Precursor solution

210. Nucleation point

220. Island-like structure

Diameter D

P spacing

Detailed Description

The perovskite solar cell structure of some embodiments of the present invention is described in detail below. It is to be understood that the following description provides many different embodiments, or examples, for implementing different aspects of some embodiments of the invention. The specific components and arrangements described below are only for simplicity and clarity in describing some embodiments of the present invention. These are, of course, merely examples and are not intended to be limiting. Furthermore, repeated reference numerals or designations may be used in the various embodiments. These repetition are for the purpose of simplicity and clarity in describing some embodiments of the invention and do not in itself dictate a relationship between the various embodiments and/or configurations discussed. Furthermore, when a first material layer is described as being on or over a second material layer, this includes situations where the first material layer is in direct contact with the second material layer. Alternatively, it is also possible that one or more other material layers are spaced apart, in which case there may not be direct contact between the first material layer and the second material layer.

Moreover, relative terms such as "lower" or "bottom" and "upper" or "top" may be used in embodiments to describe one component's relative relationship to another component of the figures. It will be appreciated that if the device of the drawings is turned upside down, the components recited on the "lower" side will be components on the "upper" side. The terms "about", "approximately" and "approximately" herein generally mean within 20%, preferably within 10%, and more preferably within 5%, or within 3%, or within 2%, or within 1%, or within 0.5% of a given value or range. The amounts given herein are about amounts, i.e., where "about", "about" or "approximately" is not specifically recited, the meaning of "about", "about" or "approximately" may still be implied.

Some embodiments of the invention provide a perovskite solar cell structure. In some embodiments, the perovskite solar cell structure comprises an induced nucleation layer. The induced crystal nucleus layer can be used as seed crystal to induce the perovskite absorption layer to nucleate at the bottom, so as to promote the perovskite crystal to grow from the bottom to the top and to the side. Therefore, the generation of crystal defects is reduced, and the crystal quality of the perovskite absorption layer is improved, so that the efficiency and stability of the perovskite solar cell structure are improved.

Referring to fig. 1, fig. 1 is a schematic cross-sectional view of a perovskite solar cell structure 100 according to some embodiments of the invention. As shown in fig. 1, the perovskite solar cell structure 100 includes a substrate 110. The substrate 110 may be a transparent conductive substrate, such as a fluorine doped Tin Oxide (FTO) substrate.

In addition, the perovskite solar cell structure 100 includes a first semiconductor layer 120. The first semiconductor layer 120 is disposed on the substrate 110. The first semiconductor layer 120 contains fullerene or 2,2', 7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino group]-9,9' -spirobifluorene (2, 2', 7' -Tetrakis [ N, N-di (4-methoxyphenyl) amino)]-9,9' -Spiro-bifluorene, spiro-OMeTAD), fullerene such as [6.6]phenyl-C61-butanoic acid methyl ester[6,6]phenyl-C61-butyric acid methyl ester, PCBM). In addition, the first semiconductor layer 120 further comprises nickel oxide (NiO), titanium dioxide (TiO ₂ ) Carbon (C), tin dioxide (SnO) ₂ ) Or other materials. In some embodiments, the first semiconductor layer 120 may be a p-type semiconductor layer or an n-type semiconductor layer.

In some embodiments, the perovskite solar cell structure comprises an induced nucleation layer 130 comprising a plurality of nucleation sites 130a (see fig. 2). The nucleation sites 130a are disposed over a portion of the first semiconductor layer 120. In some embodiments, nucleation sites 130a are hydrophobic materials. In some embodiments, the nucleation sites 130a are more hydrophobic relative to the first semiconductor layer 120. In some embodiments, the nucleation inducing layer 130 comprises indium tin oxide. (Indium Tin Oxide, ITO), nickel Oxide (NiO), molybdenum sulfide (MoS) _X ) Molybdenum oxide (MoO) _X ) Tungsten oxide (WO) _X ) Or other suitable material. The nucleation sites 130a are provided to help enable perovskite crystals to grow upward from the upper surface of the first semiconductor layer 120 during the formation of the perovskite absorption layer 140, and the perovskite absorption layer 140 formed in this manner has fewer crystal defects. A detailed process for forming the perovskite absorption layer 140 using the nucleation sites 130a will be described later.

In some embodiments, the perovskite solar cell structure 100 includes a perovskite absorber layer 140, the perovskite absorber layer 140 covering the nucleation sites 130a and formed over the first semiconductor layer 120. The general chemical formula of perovskite absorber layer 140 is ABX ₃ . Wherein A may be selected from metal ions, e.g. from Li ⁺ 、Na ⁺ 、Cs ⁺ 、Rb ⁺ 、K ⁺ Any one of the group consisting of; alternatively, a may also contain 1 to 15 carbons and 1 to 20 heteroatoms, which may be N, O or S, for example a may be methyl ammonium (methyl ammonium), formamidine (formamidinium), hydroxyl ammonium (hydroxyl ammonium), hydrazine (hydrazinium), aza ring (azetidinium), imidazole (imidozolium), dimethyl ammonium (dimethyl ammonium), ethyl ammonium (methyl ammonium), guanidine (guaninium), tetramethyl ammonium (tetramethyl ammonium) or thiazole (thiazolium). In some embodiments, A may compriseThe above materials or combinations of the above materials.

B may comprise a metal ion, e.g. selected from Li ⁺ 、Na ⁺ 、Cs ⁺ 、Rb ⁺ 、K ⁺ 、Ge ²⁺ 、Sn ²⁺ 、Mn ²⁺ 、Fe ²⁺ 、Co ²⁺ 、Ni ²⁺ 、Pd ²⁺ 、Pt ²⁺ 、Cu ²⁺ 、Zn ²⁺ 、Cd ²⁺ 、Hg ²⁺ 、Be ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ 、Ba ²⁺ 、Eu ²⁺ 、Tm ²⁺ 、Yb ²⁺ Any one of the group consisting of. In some embodiments, B may comprise more than one of the above materials or a combination of the above materials.

X is an anion, e.g. halogen, which comprises Cl ^- 、Br ^- 、I ^- . X may also comprise NCS ^- 、CN ^- 、NCO ^- Or RCOO ^- Wherein R may be methyl or ethyl. In some embodiments, X may comprise more than one of the above materials or a combination of the above materials.

In some embodiments, the compound containing A, B and X may be dissolved in a solvent to form a precursor solution, and then the perovskite absorption layer 140 may be formed by coating the precursor solution on the nucleation sites 130a and the first semiconductor layer 120, and then evaporating the solvent. This process will be described in detail later.

The perovskite solar cell structure 100 includes a second semiconductor layer 150. The second semiconductor layer 150 is disposed on the perovskite absorption layer 140. The second semiconductor layer 150 may include fullerene or 2,2', 7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino group]-9,9' -spirobifluorene (2, 2', 7' -Tetrakis [ N, N-di (4-methoxyphenyl) amino)]-9,9' -Spiro-bifluorene, spiro-OMeTAD), fullerene such as [6.6]phenyl-C61-butanoic acid methyl ester ([ 6,6 ]]phenyl-C61-butyric acid methyl ester, PCBM). In addition, the second semiconductor layer 150 further comprises NiO and TiO ₂ 、C、SnO ₂ Or other materials. In some embodiments, the second semiconductor layer 150 may be a p-type semiconductor layer or an n-type semiconductor layer, and is different in conductivity type from the first semiconductor layer 120.

The perovskite solar cell structure 100 includes a transparent conductive layer 160. The transparent conductive layer 160 is disposed on the second semiconductor layer 150. The transparent conductive layer 160 allows ambient light to be incident and has an effect of scattering the incident light, so that the light absorption efficiency is increased to improve the photoelectric conversion efficiency. The transparent conductive layer 160 may have a single-layer or multi-layer structure. The material of the transparent conductive layer 160 includes Zinc Oxide, tin Oxide, and the above doped materials, such as Fluorine (FTO) doped with Tin Oxide, aluminum (AZO) doped with Zinc Oxide, antimony (Sb-doped Tin Oxide) doped with Antimony (ATO), or other materials.

Perovskite solar cell structure 100 includes electrode 170. The electrode 170 is disposed on the transparent conductive layer 160. The electrode 170 includes a metal material, such as silver (Ag), copper (Cu), aluminum (Al), molybdenum (Mo), tungsten (W), gold (Au), chromium (Cr), nickel (Ni), platinum (Pt), or titanium (Ti).

Sunlight can enter the internal structure of the perovskite solar cell structure 100 from the substrate 110, electron holes are generated after photoelectric conversion by the first semiconductor layer 120, the second semiconductor layer 150 and the perovskite absorption layer 140, and then the electrode 170 can conduct current by providing a transfer circuit.

Referring to fig. 2, fig. 2 is a top view of a perovskite solar cell structure 100 according to some embodiments of the invention. Other components are omitted in fig. 2 for clarity of description of the arrangement of the induced nucleation layer 130, nucleation points 130a and the first semiconductor layer 120.

In some embodiments, the nucleation inducing layer 130 may be a patterned layer including a plurality of nucleation sites 130a disposed on the first semiconductor layer 120 and exposing a portion of the first semiconductor layer 120. Here, the patterned layer refers to a layer having a plurality of discontinuous blocks, which may have any identical shape or different shapes, which may have identical or different distances therebetween, and which may be arranged in any manner.

As shown in fig. 2, the plurality of nucleation points 130a are separated from each other and have a pitch P. In some embodiments, the pitch P ranges between about 0.1mm and 1.7 mm. If the pitch is less than 0.1mm, the transmittance is reduced, so that the current is reduced, thereby reducing the battery efficiency; if the spacing is greater than 1.7mm, the quality of perovskite grains will be affected. In some embodiments the intermediate distance is 0.4mm to 1.5mm, 0.5mm to 1.2mm, or 0.6mm to 1.0mm. In some embodiments, the diameter D of the nucleation sites 130a is in the range of about 30 μm to about 100 μm, such as 40 μm to 80 μm or 50 μm to 70 μm. If the diameter D is less than 30 μm, the growth space of the crystal is limited, and thus the grain size is limited; if the diameter D is larger than 100 μm, the precursor solution cannot be uniformly coated on the nucleation sites.

In some cases, if the induced nucleation layer 130 is not patterned and substantially completely covers the first semiconductor layer 120, the precursor solution of the perovskite absorber layer 140 cannot be coated on the induced nucleation layer 130 due to the hydrophobicity of the induced nucleation layer 130, so that the perovskite absorber layer 140 cannot be formed. Since the size of the nucleation sites 130a affects the crystal size of the perovskite absorber layer 140, the diameter D of the nucleation sites 130a ranges from 30 μm to 100 μm in consideration of the quality of the formed crystal and the efficiency of the perovskite solar cell structure 100.

Referring to fig. 3A-3D, fig. 3A-3D are process flow diagrams of forming an intermediate structure of perovskite solar cell 100 according to some embodiments of the invention. In detail, fig. 3A to 3D illustrate a process of forming the perovskite absorption layer 140 on the first semiconductor layer 120. In addition, the cross-section shown in FIGS. 3A-3D may be the cross-section taken along the line A-A' in FIG. 2, wherein the structure shown in FIG. 2 is a top view of the structure of FIG. 3A.

Referring to fig. 3A, in some embodiments, after forming the first semiconductor layer 120 on the substrate 110, a plurality of nucleation sites 130a are formed on the first semiconductor layer 120. The nucleation sites 130a may be formed by patterning, such as, but not limited to, evaporation, sputtering, photolithography (Lithography), screen printing, or other suitable processes. In some embodiments, a patterned shielding layer (not shown) is disposed on the first semiconductor layer 120, wherein the shielding layer has a plurality of openings exposing the surface of the first semiconductor layer 120. Next, a hydrophobic material is disposed on the first semiconductor layer 120 through the shielding layer, and then the shielding layer is removed to form the nucleation sites 130a. The arrangement of the nucleation sites 130a shown in fig. 2 corresponds to the openings of the shielding layer. By providing a shielding layer with a pattern, an induced nucleation layer 130 as shown in fig. 2, which includes a plurality of nucleation sites 130a, may be formed. The shielding layer may comprise a metal shield or other patterned shield.

As shown in fig. 3B, the precursor solution 180 is coated on the nucleation sites 130a and the first semiconductor layer 120. In some embodiments, the precursor to be perovskite-formed may be dissolved in a solvent to form precursor solution 180. The precursor of the perovskite may comprise a plurality of compounds, wherein each compound comprises any one of the group consisting of A, B or X described above. The solvent may include gamma-Butyrolactone (GBL), dimethylformamide (DMF), dimethylsulfoxide (Dimethyl Sulfoxide, DMSO), dimethylacetamide (DMAc), N-methylpyrrolidone (N-Methyl-2-pyrolone, NMP), or other suitable solvents. In some embodiments, the precursor solution 180 may be coated on the nucleation sites 130a and the first semiconductor layer 120 through a coating process.

As shown in fig. 3C, after the precursor solution 180 is applied, the solvent is evaporated, and the perovskite is crystallized to form the perovskite absorbing layer 140. The substrate 110 may be preheated to a temperature of about 300 c to facilitate solvent evaporation. Since the nucleation sites 130a have a hydrophobic relationship, the precursor solution 180 is repelled, causing the perovskite absorber layer 140 to be formed from the bottom (or upper surface of the first semiconductor layer 120). When the perovskite absorption layer 140 grows from the bottom to the top and the side, the solvent is facilitated to be completely volatilized, and crystals with few defects and larger crystal grains are formed. In some embodiments, the perovskite absorber layer 140 is in direct contact with the nucleation sites 130a and the first semiconductor layer 120.

In some cases, if the nucleation sites 130a are not used, the perovskite absorber layer will begin to crystallize from the upper surface of the precursor solution and crystallize from the upper surface toward the bottom in a manner that will block solvent evaporation so that solvent will tend to remain in the perovskite absorber layer, leaving more crystal defects in the perovskite absorber layer, such as holes formed in the absorber layer, resulting in smaller crystalline grains, and lower coverage of the perovskite absorber layer over the first semiconductor layer.

As shown in fig. 3D, after the solvent is substantially completely volatilized, a perovskite absorption layer 140 is formed on the surface of the first semiconductor layer 120. As described above, in the process of forming the perovskite absorption layer 140, the nucleation points 130a can prevent the solvent from remaining on the upper surface of the first semiconductor layer 120 to cause defects in the crystals of the perovskite absorption layer 140, and thus the provision of the nucleation points 130a helps to form the perovskite absorption layer 140 having larger crystalline grains and makes the coverage of the perovskite absorption layer 140 over the first semiconductor layer 120 higher. The larger the crystal grains of the perovskite absorber layer 140, the more helps to promote the stability of the perovskite absorber layer 140, so that the perovskite solar cell structure 100 can be used for a long period of time and maintain high efficiency.

Referring to fig. 4A-4B, fig. 4A-4B are process flow diagrams of intermediate structures forming perovskite solar cell structure 100 according to some embodiments of the invention. Referring to fig. 4A, in some embodiments, the nucleation sites 130b may be formed on the first semiconductor layer 120 prior to forming the perovskite absorber layer 140. The nucleation sites 130b may be formed by performing a modification process on the surface of the first semiconductor layer 120, for example, performing a hydrophobization process on the surface of the first semiconductor layer 120. In some embodiments, the surface of the first semiconductor layer 120 may be subjected to a plasma treatment to form radicals or functional groups having hydrophobicity on the surface of the first semiconductor layer 120 to form nucleation sites 130b.

In this embodiment, the nucleation sites 130b are embedded in the first semiconductor layer 120, and the upper surfaces of the nucleation sites 130b are substantially coplanar with the upper surface of the first semiconductor layer 120. In this embodiment, the nucleation sites 130b are a semiconductor material having hydrophobicity.

As shown in fig. 4B, after the nucleation sites 130B are formed, a perovskite absorption layer 140 is formed on the first semiconductor layer 120. The process from fig. 4A to 4B is identical or similar to the process from fig. 3A to 3D, and a description thereof will not be repeated here. In this embodiment, the patterned nucleation inducing layer 130 may be composed of a plurality of nucleation sites 130b. In addition, the material of the nucleation inducing layer 130 of this embodiment is the same as or similar to that of the first semiconductor layer 120.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below:

example 1

FTO substrates were prepared, ultrasonically cleaned with isopropyl alcohol (IPA), and then dried with nitrogen. Next, a solution containing NiO nanoparticles was coated on an FTO substrate by spin coating, and a NiO film was prepared in an environment at 300 ℃ with a thickness of about 60nm, and then a patterned metal mask was disposed on the NiO film/FTO substrate, and an induced nucleation layer having a plurality of nucleation sites, each having a diameter of about 50 μm and a spacing between the nucleation sites of about 1.0mm, was formed on the NiO film by a sputtering process, and the metal mask was removed. Next, a precursor solution for forming a perovskite absorber layer is prepared, which contains lead methylaminoiodide (Methylammonium Lead Iodide, CH ₃ NH ₃ PbI ₃ Abbreviated as MAPbI ₃ ) Gamma-butyrolactone and dimethyl sulfoxide, wherein MAPbI ₃ PbI can be used ₂ The ratio of/MAI is 1:1, the solvent is prepared by using DMSO/GBL ratio of 3:7, and MAPbI is contained in the precursor solution ₃ Is 1.2M (MAPbI) ₃ /(dmso+gbl) =1.2M). Spin-coating the precursor solution on the heated induced nucleation layer/NiO film/FTO substrate, and evaporating the solvent to form the perovskite absorption layer. Next, an n-type PCBM film was fabricated by spin-coating, wherein the thickness of the PCBM film was approximately 50nm. Next, a silver electrode was fabricated on the PCBM thin film by evaporation, wherein the thickness of the silver electrode was about 150nm, to complete the perovskite solar cell structure of example 1.

Comparative example 1

FTO substrates were prepared, ultrasonically cleaned with IPA, and then dried with nitrogen. Next, a solution containing NiO nanoparticles was coated on the FTO substrate in a spin coating manner, and a NiO film was prepared in an environment at a temperature of 300 ℃, wherein the NiO film had a thickness of about 60nm. Next, preparation is made for forming perovskite gettersA precursor solution for the capping layer comprising lead methylaminoiodide (MAPbI) ₃ ) Gamma-butyrolactone and dimethyl sulfoxide. Spin-coating the precursor solution on the heated NiO film/FTO substrate by a spin-coating method, and forming a perovskite absorption layer after the solvent is evaporated. Next, an n-type PCBM film was fabricated by spin-coating, wherein the thickness of the PCBM film was approximately 50nm. Next, a silver electrode was fabricated on the PCBM thin film by evaporation, wherein the thickness of the silver electrode was about 150nm, to complete the perovskite solar cell structure of comparative example 1.

Referring to fig. 5A to 5D, fig. 5A to 5D are enlarged views of the perovskite absorption layer shown by an optical microscope, wherein fig. 5A, 5B are enlarged views of the perovskite absorption layer of comparative example 1, fig. 5C, 5D are enlarged views of the perovskite absorption layer of example 1, the magnification of fig. 5A, 5C is 5 times, and the magnification of fig. 5B, 5D is 50 times.

Comparing FIGS. 5A and 5C, it can be seen that FIG. 5C has a plurality of dots of lighter color, spaced about 1.0mm apart, and about 100 μm in size, the positions of the dots corresponding to the formation of the nucleation sites 210 (as shown in FIG. 5D). As shown in fig. 5C, the perovskite absorber layer within the dots is lighter in color than elsewhere, because the surface of the perovskite absorber layer that grows on the nucleation sites 210 is smoother. In contrast, the perovskite absorber layer formed outside the nucleation sites 210 is darker in color, representing a rougher surface.

Comparing fig. 5B and 5D, many darker islands 220 can be found from fig. 5B. Furthermore, as can be seen from fig. 5D, there are also a number of islands 220 located in the portion outside the dots. The island structures 220 have a length in the range of about 5 μm to about 10 μm. Island structures 220 are caused by pores formed within the perovskite absorber layer. In contrast, it can be seen in fig. 5D that the surface of the perovskite absorption layer on and around the nucleation site 210 is smoother, i.e., the surface of the perovskite absorption layer formed on the induced nucleation layer is relatively less porous, so that the surface thereof is denser. Since the induced nucleation layer or nucleation sites 210 are not formed in comparative example 1, the island-like structure 220 of the perovskite absorption layer is distributed throughout the perovskite absorption layer, so that the coverage of the perovskite absorption layer is poor. In example 1, the formation of the induced nucleation layer is shown in fig. 5D, and the perovskite absorption layer on and around the nucleation point 210 does not substantially contain the island structure 220, so that the coverage of the perovskite absorption layer formed on and around the nucleation point 210 is preferable. Island 220 reduces light absorption and reduces short circuit current. In addition, the island structure 220 may cause crystal defects, which may decrease open circuit voltage and fill factor, thereby decreasing battery efficiency. Accordingly, by providing the inducing nucleation layer, the generation of crystal defects can be reduced, providing better film quality, and avoiding the problems derived from the generation of the island-like structures 220.

In some embodiments, the crystalline grains of the perovskite absorber layer formed on the nucleation sites 210 have a diameter in the range of about 20 μm to about 40 μm. And the size of the crystal grains of the perovskite absorption layer formed outside the crystal nucleus point 210 and surrounding the crystal nucleus point 210 is in the range of about 0.5 μm to about 1 μm. That is, the perovskite absorption layer formed on the induced nucleation layer has larger grains. In some embodiments, the ratio of the size of the crystalline grains of the perovskite absorber layer on the nucleation sites 210 to the size of the crystalline grains of the perovskite absorber layer outside the nucleation sites 210 is between about 20:1 to about 40:1.

From the above, the perovskite absorber layer may be divided into a first region and a second region. The first region is substantially directly above the induced nucleation layer, there is no induced nucleation layer or nucleation site below the perovskite absorption layer of the second region, and the second region surrounds and is in contact with the first region. The perovskite absorber layer in the first region has a larger crystal grain diameter than the perovskite absorber layer in the second region. In some embodiments the ratio of the crystalline diameters of the first zone to the second zone is from 20:1 to 40:1. The area of the first region projected onto the FTO substrate may be greater than or equal to the area of the nucleation site projected onto the FTO substrate. For example, the ratio of the projected area of the first region to the projected area of the nucleation point is in the range of about 1:1 to about 2:1. In addition, the first region overlaps the induced nucleation layer or nucleation point as seen in top view.

Referring to fig. 6A and 6B, fig. 6A and 6B are enlarged views of the perovskite absorption layer of example 1 shown by a scanning electron microscope. The magnification of fig. 6A is 500 times, and the magnification of fig. 6B is 5000 times. It can be seen from fig. 6B that the crystals of the perovskite absorber layer located within the dots 210 have a dendritic (dendrimer) structure. Since the interface between the induced nucleation layer and the precursor solution is hydrophobic, the perovskite crystals are disadvantageously precipitated. As the solvent evaporates, the solution becomes supersaturated and the perovskite crystals grow rapidly. Since the growth rate of the crystals is too rapid, the crystals of the perovskite absorption layer located on the induced nucleation layer take on a dendritic structure. The grain size of the dendrites can be adjusted by controlling the FTO substrate temperature. In some embodiments, the dendrite has a grain size in the range of about 20um to 40 um.

Referring to fig. 7, fig. 7 is a raman spectrum of the perovskite absorption layer of comparative example 1 and example 1. Wherein the solid line is the spectrum of example 1 and the dotted line is the spectrum of comparative example 1. The analysis light source uses laser with wavelength of 532nm, its laser spot is about 10um, and the analysis range is from 50cm ^-1 ～650cm ^-1 Resolution of 0.6cm ^-1 . The results show that comparative example 1 and example 1 were at a wave number of 76.8cm ^-1 、93.5cm ^-1 、107.7cm ^-1 、163.0cm ^-1 214.2cm ^-1 Has a peak value of 76.8cm ^-1 、93.5cm ^-1 、107.7cm ^-1 Compliance with MAPbI ₃ And 163.0cm ^-1 214.2cm ^-1 Then conform to PbI ₂ Is a peak of (c). From the peak intensity, it can be seen that the PbI of the perovskite absorption layer of example 1 ₂ /MAPbI ₃ The ratio of signal intensity is significantly lower than that of PbI of comparative example 1 ₂ /MAPbI ₃ The results show that the precursor is easier to react to MAPbI by using an induced nucleation layer ₃ Thus unreacted PbI ₂ The residual amount of (2) is smaller than that of comparative example 1.

Referring to fig. 8, fig. 8 is an X-ray diffraction analysis (XRD) spectrum of the perovskite absorption layer of comparative example 1 and example 1. Wherein the solid line is the spectrum of example 1 and the dotted line is the spectrum of comparative example 1. As can be seen from FIG. 8, the diffraction peaks are evident at 13.98 °, 19.86 °, 28.34 °, 31.82 °, 40.50 ° and 43.14 °, and the diffraction peaks conform to MAPbI ₃ Ginseng radixReading tables 1 and 2, the following is shown:

TABLE 1

2 theta/signal strength	Comparative example 1	Example 1	Comparative example 1/example 1
				13.98	61	87	0.7
19.86	23	61	0.38
				28.34	26	53	0.49
31.82	54	80	0.68
				40.5	25	45	0.56
43.14	26	43	0.6

TABLE 2

Full width at half maximum 2 theta	Comparative example 1	Example 1
			13.98	1.13	0.41
31.82	0.47	0.41

Table 1 shows the signal intensities of comparative example 1 and example 1 at peaks 13.98 °, 19.86 °, 28.34 °, 31.82 °, 40.50 ° and 43.14 °, and table 2 analyzes the full width at half maximum (Full Width at Half Maximum, FWHM) of the two diffraction peaks 13.98 ° and 31.82 ° with the strongest signal intensities. As can be seen from fig. 8, table 1 and table 2, the signal intensities of all diffraction peaks of the perovskite of example 1 are greater than those of the perovskite of comparative example 1. Further, according to table 2, the full widths at 13.98 ° of comparative example 1 and example 1 are 1.13 and 0.41, respectively, and the full widths at 31.82 ° are 0.47 and 0.41, respectively. The smaller the value of the full width at half maximum, the better the quality of the crystal. From the analysis results of table two, it can be seen that the perovskite absorber layer grown in example 1 had better crystal quality than the perovskite absorber layer prepared in comparative example 1.

Fig. 9 is a cell Open Circuit Voltage (V) of the perovskite solar cell structures of comparative example 1 and example 1 _on ) Graph of current density. The cell of example 1 had an open circuit voltage of 1.056V, a short circuit current density (Short Circuit Current Density, J _sc ) 19.76mA/cm ² The Fill Factor (f.f.) was 66.29% and the efficiency was 13.83%, wherein the solid line is example 1 and the dotted line is comparative example 1. The cell of comparative example 1 had an open circuit voltage of 1.052V and a short circuit current density of 18.59mA/cm ² The fill factor was 64.64% and the efficiency was 12.64%. According to fig. 9, the perovskite solar cell structure of example 1 has higher cell efficiency than that of the perovskite solar cell structure of comparative example 1, mainly because the coverage rate of the perovskite absorption layer formed using the induced nucleation layer is higher, and thus the current density is improved. And, the perovskite absorption layer formed by using the induced crystal nucleus layer has higher crystal quality and relatively fewer defects, so that the battery efficiency can be improved. In addition, referring to table 3, the following is true:

TABLE 3 Table 3

	V _OC (V)	J _SC (mA/cm ² )	F.F.(％)	Eff.(％)
					Nucleation free point	1.064	18.27	75.16	14.61
The distance between the crystal nucleus points is 0.6mm	1.077	18.58	75.97	15.21
					The distance between the crystal nucleus points is 1.0mm	1.078	18.63	75.96	15.26

Table 3 shows comparative tables of open circuit voltage, short circuit current density, filling factor and efficiency, in which the distances between the non-formed crystal nuclei and the crystal nuclei were 0.6mm and 1.0mm, respectively. It can be found from the table that when the distance between the crystal nucleus points is greater than 0.6mm, the open circuit voltage, the short circuit current density, the filling factor and the efficiency can be further improved than those of the parameters without forming the crystal nucleus points.

Although embodiments of the present invention and their advantages have been disclosed, it should be understood that various changes, substitutions and alterations can be made herein by those having ordinary skill in the art without departing from the spirit and scope of the invention. Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification, but rather should be understood to correspond to the particular embodiments of the present application or to the particular embodiments of the present application. Accordingly, the scope of the present application includes such processes, machines, manufacture, compositions of matter, means, methods, or steps. In addition, each claim forms a separate embodiment, and the scope of the present invention also includes combinations of the claims and embodiments.

Claims

1. A perovskite solar cell comprising:

a substrate;

a first semiconductor layer disposed on the substrate;

an induced nucleation layer disposed on the first semiconductor layer;

a perovskite absorption layer covering the induction crystal nucleus layer and the first semiconductor layer;

a second semiconductor layer disposed on the perovskite absorption layer; and

an electrode layer disposed on the second semiconductor layer,

wherein the induced nucleation layer is a hydrophobic layer.

2. The perovskite solar cell of claim 1 wherein the induced nucleation layer is a patterned layer.

3. The perovskite solar cell of claim 1, wherein the nucleation inducing layer material comprises indium tin oxide, nickel oxide, molybdenum sulfide, molybdenum oxide, or tungsten oxide.

4. The perovskite solar cell of claim 1, wherein the induced nucleation layer comprises a plurality of nucleation sites having a diameter ranging from 30 μm to 100 μm.

5. The perovskite solar cell of claim 4, wherein the spacing of the nucleation sites is in the range of 0.1mm to 1.7 mm.

6. The perovskite solar cell of claim 4, wherein the spacing of the nucleation sites is in the range of 0.4mm to 1.5 mm.

7. The perovskite solar cell of claim 1, wherein the induced nucleation layer is embedded in the first semiconductor layer and the induced nucleation layer comprises a semiconductor material having hydrophobicity.

8. The perovskite solar cell of claim 1 wherein the perovskite absorber layer comprises a first region located directly above the inducing nucleation layer and a second region surrounding and in contact with the first region, the ratio of the diameter of the crystalline grain located in the first region to the diameter of the crystalline grain located in the second region being 20:1 to 40:1.

9. The perovskite solar cell of claim 8, wherein the crystalline grain located within the first region has a diameter ranging from 20 μιη to 40 μιη.

10. The perovskite solar cell of claim 1, wherein the perovskite absorber layer comprises dendrite of dendritic structure.

11. A method of manufacturing a perovskite solar cell, comprising:

providing a substrate;

forming a first semiconductor layer on the substrate;

forming an induced nucleation layer on the first semiconductor layer;

forming a perovskite absorption layer to cover the induction crystal nucleus layer and the first semiconductor layer;

forming a second semiconductor layer on the perovskite absorption layer; and

forming an electrode layer on the second semiconductor layer,

wherein the induced nucleation layer is a hydrophobic layer.

12. The method of claim 11, further comprising:

patterning the induced nucleation layer to form a plurality of nucleation sites spaced apart from each other.

13. The method of claim 11, wherein the nucleation inducing layer material comprises indium tin oxide, nickel oxide, molybdenum sulfide, molybdenum oxide, or tungsten oxide.

14. The method of claim 11, further comprising:

a hydrophobization treatment is performed on the first semiconductor layer to form the induced nucleation layer.