KR102098774B1 - Perovskite Solar Cell having Improved Efficiency and Stability, and the Fabrication Method Thereof - Google Patents

Abstract

The perovskite solar cell according to the present invention is located in the perovskite compound grains and grain boundaries, which are organic metal halides of the perovskite structure, and includes an alkylammonium metal halide surrounding the grain. In addition, in the X-ray diffraction pattern using Cu Kα rays, a perovskite compound film in which only a crystal structure by a 3D perovskite compound grain is present is included as a light absorbing layer.

Description

Perovskite Solar Cell having Improved Efficiency and Stability, and the Fabrication Method Thereof

The present invention relates to a perovskite solar cell having improved efficiency and stability, and a method for manufacturing the same, in detail, while having excellent efficiency, and having excellent stability against an external environment including heat, light, moisture, and oxygen. The present invention relates to a lobsky solar cell and a method for manufacturing the same.

Currently, perovskite solar cells using organometal halide (organometal halide) having a perovskite structure as a light absorber are closest to commercialization among next-generation solar cells, including dye-sensitized and organic solar cells. , As the efficiency of reaching 22% or more is reported (Registration No. 1547870 in Korea), interest is increasing.

However, although the photoelectric conversion efficiency has been greatly improved, the perovskite solar cell has environmental instability to light (light), heat, moisture, and oxygen under operating conditions, and thus has great difficulty in commercialization. It has been interpreted that the severe decomposition of perovskite solar cells in a humid environment is due to the hygroscopicity of organic cations and the weak metal-halogen interaction. In addition, severe thermal stress under oxygen and moisture conditions is known to promote the decomposition of solar cells due to volatility of organic cations. In addition, the formation of deep traps by photoelectrons and the reduction of halogens significantly degrade the photostability of the solar cells. Moreover, it is known that the decomposition of perovskite compounds begins at grain boundaries and surface defects when exposed to moisture or oxygen conditions.

In order to improve the stability of the perovskite compound, the technology of forming a separate moisture barrier layer on the upper or lower portion of the light absorbing layer as in Korean Patent Registration No. 1763824, the substance itself of the perovskite compound as in Korean Patent Registration No. 1715253 Technology that specializes in has been proposed.

However, despite these technological advances, the development of a technology capable of ensuring improved stability against all of heat, light, moisture and oxygen is still in demand. Furthermore, in order to commercialize the perovskite solar cell, photoelectric conversion efficiency There is a need to develop a technology capable of improving stability against heat, light, moisture and oxygen without sacrificing.

Republic of Korea Registered Patent No. 1547870 Republic of Korea Registered Patent No. 1723824 Republic of Korea Registered Patent No. 1715253

An object of the present invention is to provide a perovskite solar cell having excellent photoelectric conversion efficiency and improved stability against heat, light, moisture and oxygen, and a method for manufacturing the same.

The perovskite solar cell according to the first aspect of the present invention is located in the perovskite compound grain and grain boundary, which is an organometallic halide of the perovskite structure, and surrounds the grain and has a C6 or higher normal. A perovskite compound film containing an alkylammonium ion and a non-crystalline grain boundary layer; and a light absorbing layer.

In one embodiment according to the first aspect of the present invention, the ammonium group of the normal alkylammonium ion may be bonded to the metal-halogen inorganic skeleton of the perovskite compound grain.

In one embodiment according to the first aspect of the present invention, the alkyl of the normal alkylammonium ion may be C8 to C12 normal alkyl.

In one embodiment according to the first aspect of the present invention, the perovskite compound membrane may contain 0.5 to 5 mol% of normal alkylammonium ions.

The perovskite solar cell according to the second aspect of the present invention is located in the perovskite compound grain and grain boundary, which is an organic metal halide of the perovskite structure, and covers the organic monomolecular film surrounding the grain. The perovskite compound film is included as a light absorbing layer.

In one embodiment according to the second aspect of the present invention, the molecule of the organic monomolecular film comprises a -NH ₃ ⁺ head group and a C6 or higher alkyl chain bonded to the metal-halogen inorganic skeleton of the perovskite compound grain. It may be a single molecule.

In one embodiment according to the second aspect of the present invention, the C6 or higher alkyl chain may be C8 to C12 normal alkyl.

In one embodiment according to the second aspect of the present invention, the perovskite compound film may contain 0.5 to 5 mol% of an organic single molecule.

The perovskite solar cell according to the third aspect of the present invention is located on the perovskite compound grain and grain boundary, which is an organometal halide of the perovskite structure, and surrounds the grain with alkylammonium It includes a metal halide, and includes a perovskite compound film having only a crystal structure by a three-dimensional perovskite compound grain in an X-ray diffraction pattern using Cu Kα rays as a light absorbing layer.

In one embodiment according to the third aspect of the present invention, the alkyl of the alkylammonium metal halide may be C6 or higher normal alkyl.

In one embodiment according to the third aspect of the present invention, the alkyl of the alkylammonium metal halide may be C8 to C12 normal alkyl.

In one embodiment according to the third aspect of the present invention, the perovskite compound membrane may contain 0.5 to 5 mol% of an alkylammonium metal halide.

In one embodiment according to the present invention (including the first, second or third aspect), the perovskite compound film has an average grain size based on the membrane surface of 200 to 700 nm, and a perovskite compound film surface reference unit The porosity, which is the ratio of the pore area per area, may be 0.05 or less.

In one embodiment according to the invention (including the first, second or third aspect), the solar cell comprises a first electrode; An electron carrier positioned on the first electrode; And a light absorbing layer including the perovskite compound film covering the electron transporter. A hole transporter located on the light absorbing layer; And a second electrode.

In one embodiment according to the present invention (including the first, second or third aspect), the perovskite compound film is a diffraction angle of 2θ from 3.5 to 12.0 ° in X-ray diffraction measurement using Cu-Kα ray. Diffraction peaks in the range of may not be detected.

In one embodiment according to the present invention (including the first, second or third aspect), the perovskite compound film is diffracted by the (110) plane in an X-ray diffraction measurement using Cu-Kα rays. The peak full width at half maximum (FWHM) may be 0.16 ° or less.

In one embodiment according to the present invention (including the first, second or third aspect), the perovskite compound membrane may satisfy the following relational expression 1.

(Relationship 1)

I (110) / I ₀ (110) ≥ 2

In the relational expression 1, I (110) is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the perovskite compound film, and I ₀ (110) is the perovskite compound It is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of a reference light-absorbing layer made of polycrystals of the same perovskite compound grains as the film.

In one embodiment according to the present invention (including the first, second or third aspect), the perovskite compound membrane scatters with the scattering vector component q _z as the y axis and the scattering vector component q _xy as the x axis. Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) spectrum using monochromatic X-rays, which is an intensity distribution, has a non-uniform scattering intensity on the (110) plane, and is most effective at q _xy = 0. It can have a large scattering intensity.

A method of manufacturing a perovskite solar cell according to the present invention comprises the steps of: a) forming an electron carrier on a first electrode; b1) C6 or higher normal alkylammonium halide on the electron transporter; An organic halide which is a halide of a monovalent organic ion constituting an organometal halide having a perovskite structure; And forming a light absorbing layer by applying a liquid containing a divalent metal halide. And c) sequentially forming a hole transporter and a second electrode on the light absorbing layer.

A method of manufacturing a perovskite solar cell according to the present invention comprises the steps of: a) forming an electron carrier on a first electrode; b2) a light-absorbing layer by sequentially applying a liquid containing a perovskite compound that is an organometallic halide of a perovskite structure on the electron transporter and a liquid containing a C6 or higher normal alkylammonium halide and a divalent metal halide. Forming; And c) sequentially forming a hole transporter and a second electrode on the light absorbing layer.

In the method of manufacturing a perovskite solar cell according to an embodiment of the present invention, C6 or higher normal alkyl may be C8 to C12 normal alkyl.

In the method of manufacturing a perovskite solar cell according to an embodiment of the present invention, the liquid in step b) may have a number of moles of a divalent metal halide: a mole number of a normal alkylammonium halide of C6 or higher may be 100: 0.5 to 5 have.

The perovskite solar cell according to an embodiment of the present invention has a structure in which the perovskite compound grain is wrapped by an organic capping agent, thereby significantly improving stability against an external environment including heat, light, moisture, and oxygen. It has the advantage of excellent compatibility.

In addition, the perovskite solar cell according to an embodiment of the present invention, despite having a structure in which a three-dimensional perovskite compound crystal (grain) is wrapped by an organic capping agent, is a conventional pure perovskite It has an advantage of having a photoelectric conversion efficiency superior to that of a solar cell equipped with a light absorbing layer made of a compound polycrystalline.

In addition, the perovskite solar cell according to an embodiment of the present invention can be manufactured by using the solution coating method, which is the greatest advantage of the perovskite solar cell, without any high technical modification, and the conventional perovskite. Since there is no additional process required in the manufacturing process of the sky solar cell, it has the advantage of having excellent commerciality.

1 is a view showing the differential scanning calorimetry (DSC) measurement results of the perovskite powder used in the preparation of the organic capping agent-perovskite solution in Examples 1, 2, 3 and Comparative Example 1,
2 is octylammonium modified perovskite used for preparation in Comparative Example 1 (0% OA), Example 1 (3.3% OA), Example 2 (4.9% OA) and Example 3 (9.5% OA). It is a diagram showing the FTIR spectrum of the powder,
3 is an X-ray diffraction result of the light absorbing layers prepared in Examples 1, 2, 3 and Comparative Example 1 (FIG. 3 (a)) and a scanning electron microscope photograph (Fig. 3 (b)) observing the surface of the light absorbing layer. , Scale bar = 500nm), GIWAXS measurement result (FIG. 3 (c)), charge carrier recombination lifetime measured by time correlated single photon counting (TCSPC) (FIG. 3 (d)) and X- by (110) plane FWHM of the line diffraction peak, diffraction peak intensity and PL life time (Fig. 3 (e)) is a diagram showing,
Figure 4 is a schematic diagram showing the structure of the perovskite thin film along the length of the alkyl chain, Figure 4 (a) is an octylammonium (OA) modified perovskite thin film, Figure 4 (b) is butyl ammonium (BA ) Modified perovskite membrane and phenethylammonium (PEA) modified perovskite membrane, FIG. 4 (c) is a schematic view of a pure perovskite membrane, and FIGS. 4 (d) to (g) are 50 mol% OA Perovskite film containing (Fig. 4 (d)), perovskite film containing 50 mol% PEA (Fig. 4 (e)), perovskite film containing 50 mol% BA (Fig. 4 (f)) and A diagram showing the X-ray diffraction results of a pure perovskite film,
Figure 5 is Comparative Example 1 (0% OA, Figure 5 (a), Figure 5 (d)), Example 1 (3.3%, OA Figure 5 (b), Figure 5 (e)) and Example 3 (9.5 % OA, FIG. 5 (c), FIG. 5 (f)) shows the results of EDX element mapping in the red line across the grain boundary in the HAADF-STEM observation and HAADF-STEM observation pictures of the light absorbing layer. 5 (g) is a view showing a BF-STEM (Bright-field scanning transmission electron microscopy) observation photo of the light absorbing layer prepared in Example 1,
Figure 6 (a) is a view showing a cross-sectional scanning electron microscope observation photo (scale bar = 500nm) of a solar cell (Example 1) equipped with a light absorption layer containing 3.3 mol% OA, Figure 6 (b) Twenty pieces prepared in Comparative Example 1 (OA = 0 mol%), Example 1 (OA = 3.3 mol%), Example 2 (OA = 4.9 mol%), and Example 3 (OA = 9.5 mol%), respectively. FIG. 6 (c) is a diagram showing the current density-voltage graph of the solar cells of Comparative Example 1 and Example 1, and FIG. 6 (d) is an example. 1 (3.3 mol% OA) is a diagram showing the external quantum efficiency (EQE) spectrum of a solar cell manufactured in Figure 6 (e) is a stabilized photoelectric photovoltaic cell prepared in Example 1 (3.3 mol% OA) It is a drawing showing the conversion efficiency,
7 is a thermal stability test result of the solar cell prepared in Comparative Example 1 and the solar cell prepared in Example 1 (Fig. 7 (a)), moisture stability test results (Fig. 7 (b)), light stability test results ( 7 (b)) A scanning electron microscope observation photograph observing the surface of the light absorbing layer before and after the thermal stability test in Comparative Example 1 and Example 1, and a schematic diagram and a scanning electron microscope observation photograph observing the surface of the light absorbing layer before and after electron beam irradiation. It is a diagram showing a schematic diagram and
Figure 8 measures the thermal stability of the solar cell prepared in Example 1, Comparative Example 1 (0mol% OA), Comparative Example 2 (3.3mol% BA) and Comparative Example 3 (3.3mol% PEA) 8 (a)) and the thermal stability of the solar cells manufactured in Examples 1 to 3 (FIG. 8 (b)).

Hereinafter, a perovskite solar cell and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below, and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, unless there are other definitions in the technical terms and scientific terms to be used, those skilled in the art to which this invention pertains have the meanings commonly understood, and the subject matter of the present invention in the following description and accompanying drawings Descriptions of well-known functions and configurations that may be obscured are omitted.

In the present invention, the perovskite solar cell is a perovskite organic metal halide (AMX ₃ , A = monovalent organic cation or Cs ⁺ , M = divalent metal, X = halogen, hereinafter, Fe Means a solar cell containing a lobsky compound) as a light absorber.

The solar cell according to the present invention includes a perovskite compound film as a light absorbing layer, and the perovskite compound film is a polycrystalline film, which is located at the perovskite compound grain and grain boundary to obtain grain. Includes a wrapping grain boundary layer.

In the present invention, as the material of the grain boundary layer is chemically bonded to the perovskite compound grain, the first aspect of the present invention detailed in terms of the material present in the space (position) between the grain and the grain, bonding with the grain The third aspect of the present invention includes the third aspect of the present invention from the viewpoint of a chemically independent material that satisfies conditions and satisfies charge neutralization conditions and the like. In addition, the present invention includes the second aspect described above with respect to the first aspect and the third aspect, from the structural point of view and further from the manufacturing method point of view.

The perovskite solar cell according to the first aspect of the present invention is located in the perovskite compound grain and grain boundary, which is an organometallic halide of the perovskite structure, and surrounds the grain and is C6 or higher. A perovskite compound film containing a normal alkylammonium ion and a non-crystalline grain boundary layer; and a light absorbing layer.

The perovskite solar cell according to the third aspect of the present invention is located on the perovskite compound grain and grain boundary, which is an organometal halide of the perovskite structure, and is an alkyl surrounding the grain. It includes an ammonium metal halide, and includes a perovskite compound film having only a crystal structure by a three-dimensional perovskite compound grain in an X-ray diffraction pattern using Cu Kα rays as a light absorbing layer.

The solar cell according to the second aspect of the present invention comprises a perovskite compound perovskite compound grain and a grain boundary layer located at a grain boundary and an organic monomolecular film surrounding the grain. The lobsky compound film is included as a light absorbing layer.

The material viewpoint of the grain boundary layer considering the chemical bond with the perovskite compound grain (the third aspect), the material viewpoint of the grain boundary layer physically located between the grain and the grain (the first embodiment), and the structural viewpoint of the grain boundary layer ( All of the third aspect) are those described above with different main viewpoints of the perovskite compound membranes included in the solar cell according to the present invention, and are specifically limited to any one aspect (first aspect, etc.) in the detailed description below. Needless to say, unless otherwise stated, all of the contents presented below are included in each of the first, second, and third aspects.

In the solar cell according to an embodiment, the perovskite compound film included as the light absorbing layer includes perovskite compound grain and grain boundary and includes an alkylammonium metal halide surrounding the grain. , In the X-ray diffraction pattern using Cu Kα rays, only the crystal structure by the 3D perovskite compound grain may exist. At this time, the fact that only the crystal structure by the three-dimensional perovskite compound grain exists is a three-dimensional grain by reaction between an alkylammonium metal halide or an alkylammonium ion derived from an alkylammonium metal halide and a perovskite compound. It means that a crystalline different from the perovskite compound constituting the 2D crystal is not generated. That is, in the solar cell according to an embodiment, the perovskite compound film included as the light absorbing layer does not have crystallinity including two-dimensional crystals in the grain boundary, and is two-dimensional in an X-ray diffraction pattern using Cu Kα rays. There are no peaks (diffraction peaks) due to the structure, and only a crystal structure by the three-dimensional perovskite compound grain may be present.

Specifically, the perovskite compound film may include a perovskite compound grain and a one-dimensional () alkylalkyl metal halide located on a grain boundary and surrounding the grain. At this time, the one-dimensional (()) alkyl ammonium metal halide may mean that the alkyl ammonium metal halide wraps the perovskite compound grain (three-dimensional crystal) in the form of a monolayer. That is, the 1-dimensional alkyl ammonium metal halide may mean a single layer of alkyl ammonium metal halide.

 The solar cell according to an embodiment includes heat, light, moisture, and oxygen as the perovskite compound crystal (grain), which is a three-dimensional solid (3D), has a structure surrounded by a one-dimensional alkylammonium metal halide. It can have surprisingly improved stability against the external environment.

 In the solar cell according to an embodiment, the perovskite compound film has a structure in which a perovskite compound grain (three-dimensional crystal) having a three-dimensional structure (3D) is wrapped by a one-dimensional alkylammonium metal halide, It does not contain a separate crystalline phase other than perovskite compounds or grains. That is, the perovskite compound film does not have a peak due to a two-dimensional structure on an X-ray diffraction pattern using Cu Kα rays, and only a crystal structure by a three-dimensional perovskite compound grain may exist. This means that an alkylammonium metal halide is located in the grain boundary, but a separate crystal phase such as a layered perovskite structure is not formed at the interface by reaction between the alkylammonium metal halide and the perovskite compound. it means. That is, the grain boundary layer is non-crystalline, which does not form a separate crystal phase.

Due to these crystal structural characteristics, the perovskite compound film may not detect diffraction peaks in the range of diffraction angles 2θ 3.5 to 12.0 ° in X-ray diffraction measurement using Cu-Kα rays. The range of 2θ 3.5 to 12.0 ° is a 2θ range in which diffraction peaks due to separate crystal phases such as a layered perovskite structure appear.

Specifically, the perovskite compound film has no peak due to a two-dimensional structure in X-ray diffraction measurement using Cu-Kα rays, and is attributed to the perovskite structure of the three-dimensional perovskite compound grain. A peak other than one diffraction peak may not be present, and may have a diffraction pattern substantially the same as the X-ray diffraction pattern of the film made of perovskite compound grain (s). At this time, substantially the same means that the weak shift of the peak center or the peak broadening should be considered in the diffraction pattern.

Advantageously, the alkyl of the alkylammonium metal halide may be C6 or higher normal alkyl. That is, in an advantageous example, the alkylammonium metal halide may be a C6 or higher normal alkylammonium metal halide.

C6 or more, specifically C6 to C12 alkyl ammonium metal halide is located on each grain boundary and surface defects of the perovskite compound and can wrap each perovskite compound grain in three dimensions, perovskite compound Each grain may be wrapped without forming a separate crystal phase (eg, a layered perovskite structure) other than the perovskite structure derived from the grain.

When the alkyl ammonium metal halide wraps each grain without forming a separate crystal phase, stability to heat, light, moisture, and oxygen may be significantly improved. In addition, by a long chain of normal alkyl of C6 or more, strong interactions are caused by van der Waals forces between the chains, and a hydrogen bond between the ammonium functional group (-NH ₃ ⁺ ) and the perovskite inorganic skeleton is formed, By attaching the alkyl chain to the metal-halogen termination surface, it can have surprisingly good thermal and light stability, together with preventing non-radiative recombination at the defect sites, and perovskite compound grains in the membrane are highly preferred. Caused to have an orientation, even if the grains are capped by a one-dimensional alkylammonium metal halide, the cell efficiency of the solar cell can be greatly improved.

The perovskite compound grains are wrapped with an alkylammonium metal halide to have improved stability against heat and light, and a smooth flow of photocurrent can be guaranteed even when the perovskite compound grains are wrapped with an alkylammonium metal halide. The alkyl of the alkylammonium metal halide may be C8 to C12 normal alkyl, and even more advantageously C8 to C10 normal alkyl, so as to have a stronger preferential orientation and to form coarse grains. Excellent thermal stability that maintains an efficiency of at least 85% based on the initial efficiency at a thermal environment of 85 ° C. and at a time point of exposure to 432 hours by the C8 to C12 normal alkylammonium metal halide, advantageously the C8 to C10 normal alkylammonium metal halide. In case of continuous sunlight (including UV) irradiation at room temperature AM1.5G, it can have excellent light stability that maintains an efficiency of 70% or higher based on the initial efficiency at the time of 75 hours irradiation, and exposes 570 hours under 65% relative humidity At the time point, it can have excellent moisture stability, which maintains an efficiency of 85% or more compared to the initial efficiency, and has improved photoelectric conversion efficiency by 18% or more compared to a solar cell made of a conventional pure perovskite grain by coarse grain size and strong priority orientation. , Specifically, may have a photoelectric conversion efficiency of 20% or more.

As described above, the C6 to C12 normal alkylammonium metal halide, advantageously the C8 to C12 normal alkylammonium metal halide, and more advantageously the C8 to C10 normal alkylammonium metal halide has a very strong preferential orientation to the light absorbing layer. Can cause.

In detail, the perovskite compound membrane is formed by a C6 to C12 normal alkylammonium metal halide, advantageously a C8 to C12 normal alkylammonium metal halide, and more advantageously a C8 to C10 normal alkylammonium metal halide. 1, specifically, may have a preferred orientation that satisfies relational expression 1-1.

(Relationship 1)

I (110) / I ₀ (110) ≥ 2

In the relational expression 1, I (110) is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the perovskite compound film, and I ₀ (110) is the perovskite compound It is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of a reference light-absorbing layer made of polycrystals of the same perovskite compound grains as the film. At this time, the thickness of the light absorbing layer (perovskite compound film) in which I (110) and I ₀ (110) are measured may be substantially the same, as well as the same method and the same process of coating and drying the liquid. Of course, it can be manufactured under conditions.

(Relationship 1-1)

I (110) / I ₀ (110) ≥ 2.7

In relation 1-1, I (110) and I ₀ (110) are the same as the definition of relation 1.

In another aspect, the C6 to C12 normal alkylammonium metal halide, advantageously a C8 to C12 normal alkylammonium metal halide, more advantageously a C8 to C10 normal alkylammonium metal halide, the light absorbing layer is a scattering vector component q Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) spectrum using monochrome X-rays, which is a scattering intensity distribution with _z as the y-axis and scattering vector component q _xy as the x-axis, ( 110) It has a non-uniform (discontinuous) scattering intensity of the surface, and may have the largest scattering intensity at q _xy = 0. As q _xy = 0 has a very large scattering intensity, it means that most of the perovskite compound grains contained in the light absorbing layer have an orientation in which the (110) plane is arranged parallel to the surface of the light absorbing layer. The solar cell efficiency can be remarkably improved by the orientation of the (110) plane.

Furthermore, the C6 to C12 normal alkylammonium metal halide, advantageously the C8 to C12 normal alkylammonium metal halide, and more advantageously the C8 to C10 normal alkylammonium metal halide, is a very coarse and excellent crystallinity perovskite. By enabling the formation of skyt compound grains, solar cell efficiency can be further improved.

The crystallinity of the perovskite compound grains in the perovskite compound film can be evaluated using the broadening of the peaks in the X-ray diffraction pattern. The perovskite compound film may satisfy the following relational expression (2), and substantially, in the X-ray diffraction measurement using Cu-Kα ray of the perovskite compound film, FWHM (Full Width) of the diffraction peak by the (110) plane at Half Maximum) may be 0.16 ° or less, and more substantially 0.15 ° or less.

(Relational formula 2)

FWHM (110) / FWHM ₀ (110) x 100 ≤ 90

In relation 2, FWHM 110 is the FWHM of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the light absorbing layer, and FWHM ₀ (110) has the same thickness as the light absorbing layer and has the same thickness. It is the FWHM of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα ray of the reference light-absorption layer made of polycrystalline of the grain of the Lobsky compound.

Specifically, with high crystallinity satisfying the above-mentioned relational expression 2, the average grain size of the perovskite compound film may be 200 to 700 nm, more specifically, 300 to 700 nm, and the unit area based on the surface of the perovskite compound film It may be a dense film having a porosity of 0.05 or less, specifically 0.01 or less, which is a ratio of the sugar pore area. At this time, the average grain size may be the average size calculated by measuring the size of the grains exposed on the surface by observing the surface of the perovskite compound film with a scanning electron microscope, and porosity is also scanned by the surface of the perovskite compound film Observing with an electron microscope, the ratio of the area occupied by the pore (s) trapped in a triple point or the like may be calculated from the total area of the surface to be observed.

Advantageously, the perovskite compound membrane may contain 0.5 to 5 mole percent alkylammonium metal halide. When the perovskite compound film contains less than 0.5 mol% of alkyl ammonium metal halide, the thermal and light stability improvement effect by the alkyl ammonium metal halide may be difficult to express, firstly, the orientation-forming effect may be exhibited, and it exceeds 5 mol%. In the case of containing an alkylammonium metal halide, the structure wrapped with a single film is difficult to form, the crystallinity of the perovskite compound grains is greatly reduced, crystal growth is very suppressed, and at the same time, the preferential orientation of the (110) plane is also greatly reduced and charge The recombination life time is also significantly reduced, so that the efficiency of a solar cell can be significantly reduced compared to a solar cell equipped with a reference light absorbing layer made of perovskite compound grains, and light and thermal stability are inhibited by excessive alkylammonium metal halide. Can be. Accordingly, the light absorbing layer preferably contains 0.5 to 5 mol%, more preferably 0.5 to 4 mol%, and more advantageously 0.1 to 4 mol% of an alkylammonium metal halide.

The metal of the alkyl ammonium metal halide may be a divalent metal ion, specifically Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Ge ²⁺ , Sn ²⁺ , Pb ²⁺ and Yb ²⁺ may be one or two or more, and may be advantageously the same as the metal of the perovskite compound forming a grain. Further, the halogen of the metal alkyl ammonium halide is I ^-, Br ^-, F ^- and Cl ^- can be alone or in combination of two or more selected from, can advantageously be equal to the perovskite compound in the grain halogen.

When the alkyl ammonium metal halide contains the same metal and halogen as the grain perovskite compound, the metal and halogen of the alkyl ammonium metal halide form a metal-halogen forming the terminated surface of the perovskite compound grain. Can respond to. That is, the structure in which the grain is wrapped in a one-dimensional alkyl ammonium metal halide, the grain (three-dimensional crystal of the perovskite compound) is terminated with a metal-halogen (alkyl), and the alkyl ammonium ion is on the surface of the terminated grain (crystal). It may correspond to a structure that forms a single alkylammonium layer that binds and surrounds the grain (three-dimensional crystal of perovskite compound).

As described above, it can be seen that the metal-halogen of the alkylammonium metal halide belongs to the metal-halogen inorganic skeleton of the grain of perovskite compound, and the metal-halogen which is the end surface of the perovskite compound crystal. It can be regarded as belonging, and it can be seen that an alkylammonium ion is located at a grain boundary, which is a region between the perovskite compound crystal and the perovskite compound crystal.

Accordingly, in one advantageous example, the perovskite compound perovskite compound is a perovskite compound grain and a grain boundary located at a grain boundary, and the C6 or higher normal alkyl ammonium metal halide surrounding the grain A perovskite compound film containing only a crystal structure by a three-dimensional perovskite compound grain in an X-ray diffraction pattern using Cu Kα rays, perovskite is an organometallic halide of perovskite structure It may correspond to a perovskite compound membrane that is located at a grain boundary and a grain boundary, surrounds the grain, contains a C6 or higher normal alkylammonium ion, and includes a non-crystalline grain boundary layer.

At this time, the ammonium group (-NH ₃ ⁺ ) of the normal alkylammonium ion of the grain boundary layer may be bound to the metal-halogen inorganic skeleton of the perovskite compound grain, specifically a chemical bond, more specifically a hydrogen bond. In other words, the ammonium group (-NH ₃ ⁺ ) of the normal alkylammonium ion of the grain boundary layer is bound to the metal-halogen termination surface of the perovskite compound grain, specifically a chemical bond, more specifically a hydrogen bond. You can.

In view of this, in view of the method of manufacturing a perovskite compound membrane using a solution coating method, the dissolved perovskite compound crystallizes (nucleates) and grows, and the perovskite compound crystal surface is metal by alkylammonium ions. -It is terminated with halogen and self-assembled on the surface of the alkyl ammonium to form a structure in which the alkyl chain wraps the three-dimensional crystal (grain) of the perovskite compound. In addition, the chain of alkyl chains derived from both grains is caused by the interchain interaction of the alkyl chain of one grain (grain A) and the alkyl chain of another grain (grain B) forming a grain boundary with one grain (grain A). The strong interaction of the liver forms one aligned monolayer and may cause strong preferential orientation of the aforementioned grains.

That is, during the nucleation and growth of the perovskite compound, the ammonium group of the alkylammonium ion spontaneously binds to the metal-halogen termination surface of the perovskite compound crystal, and the alkyl chain of the alkylammonium ion is perovskite. A perovskite compound film having a structure surrounding the crystal of the compound may be formed. At this time, the normal alkyl chain of C6 or more may form a monomolecular membrane structure substantially similar to a self-assembled monoyer (SAM) by the anti-Dervals force between the chains. In addition, normal alkyl chains of C12 or lower, due to strong van der Waals force and proper chain length, do not form a monomolecular film of the alkyl chain in each of the two grains forming the grain boundary, but rather belong to the two grains forming the grain boundary. Chains penetrate each other and can form a single molecular film by the anti-Der Waals force between the chains.

Accordingly, the one-dimensional alkylammonium metal halide, which is located in the perovskite compound grain and grain boundary and surrounds the grain, can be interpreted as a monomolecular film of alkylammonium self-assembled in the perovskite compound grain.

In this structural aspect, according to an advantageous example, the perovskite compound perovskite compound is a perovskite compound grain and grain boundary located on the grain boundary and the C6 or higher normal alkyl ammonium metal surrounding the grain A perovskite compound film containing a halide and having only a crystal structure by perovskite compound grains in an X-ray diffraction pattern using Cu Kα rays is perovskite, an organometal halide of perovskite structure. It may correspond to a perovskite compound film including an organic monomolecular film that is located at the grain and grain boundaries and surrounds the grain. At this time, the molecule of the organic monomolecular film may correspond to the alkylammonium ion of the alkylammonium metal halide. That is, the molecule of the organic monomolecular film may be an alkylammonium ion having a -NH ₃ ⁺ head group and a C6 or higher alkyl chain bonded to the metal-halogen inorganic skeleton of the perovskite compound grain.

In the solar cell according to an embodiment of the present invention, the perovskite compound, which is a light absorber, may be an organometal halide that satisfies Formula 1, but is not limited thereto. Any material may be any organic metal halide having a perovskite structure known to be used as a light absorber to be produced.

(Formula 1)

AMX ₃

In formula 1, A is a monovalent organic cation, or Cs ^+, M is a divalent metal ion, X is I ^-, Br ^-, F ^- and Cl ^- can be alone or in combination of two or more selected from the. Examples of the bivalent metal ion M, Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Ge ²⁺ , Sn ²⁺ , Pb ¹⁺ or 2 or more selected from ²⁺ and Yb ²⁺ , but are not limited thereto. A may be an amidinium group ion, an organic ammonium ion, or an amidinium group ion and an organic ammonium ion. The organic ammonium ion is of the formula (R ₁ -NH ₃ ⁺ ) (R ₁ is C1-C24 alkyl, C3-C20 cycloalkyl or C6-C20 aryl) or (R ₂ -C ₃ H ₃ N ₂ ⁺ - R ₃ ) (R ₂ is C1-C24 alkyl, C3-C20 cycloalkyl or C6-C20 aryl, and R ₃ is hydrogen or C1-C24 alkyl). In one non-limiting and specific example, R ₁ may be C ₁ -C ₂₄ alkyl, preferably C ₁ -C 5 alkyl, more preferably methyl. R ₂ may be C1-C24 alkyl and R ₃ may be hydrogen or C1-C24 alkyl, preferably R ₂ may be C1-C5 alkyl and R ₃ may be hydrogen or C1-C5 alkyl, More preferably R ₂ can be methyl and R ₃ can be hydrogen.

The amidinium-based ion may satisfy Formula 2 below.

(Formula 2)

At this time, in the formula (2) R ₄ to R ₈ are independently of each other, hydrogen, C1-C24 alkyl, C3-C20 cycloalkyl or C6-C20 aryl. Non-limiting and specific examples, taking into account the absorption of sunlight, R ₄ to R ₈ are independently of each other, hydrogen, amino or C1-C24 alkyl, specifically hydrogen, amino or C1-C5 alkyl, more specifically hydrogen, It can be amino or methyl. Even more specifically, R ₄ may be hydrogen, amino or methyl and R ₅ to R ₈ may be hydrogen. As a specific and non-limiting example, the amidinium-based ion is formamidinium (NH ₂ CH = NH ₂ ⁺ ) ion, acetamidinium (NH ₂ C (CH ₃ ) = NH ₂ ⁺ ) Or a guamidinium (Guamidinium, NH ₂ C (NH ₂ ) = NH ₂ ⁺ ).

As described above, the monovalent organic ion (A) of the organometal halide is a monovalent organic ammonium ion of R ₁ -NH ₃ ⁺ or R ₂ -C ₃ H ₃ N ₂ ⁺ -R ₃ described above, based on the formula As described above, the amidinium-based ion, or the organic ammonium ion and the amidinium-based ion may be used.

When the monovalent organic ion contains both the organic ammonium ion and the amidinium-based ion, the organohalide is A ^' _1-x A _x (A is the monovalent organic ammonium ion described above, and A ^' is the aforementioned amididi Needle umgye ion, x is I ^-, Br ^-, F ^- and Cl ^- is a halogen ion that is one or two or more selected from, x is a real number 0 <x <1, preferably from 0.3 mistake 0.05≤x≤) The formula can be satisfied. When the total number of moles of monovalent organic cations is 1, and contains amidinium ions of 0.7 to 0.95 and organoammonium ions of 0.3 to 0.05, it is possible to absorb light in a very wide wavelength band, but is faster exciton (exciton) ) Is advantageous because it enables the movement and separation, and the faster movement of photoelectrons and holes.

A solar cell according to an embodiment includes a first electrode; An electron carrier positioned on the first electrode; And the above-described perovskite compound film covering the electron transporter. Light absorbing layer; A hole transporter located on the light absorbing layer; And a second electrode.

The perovskite compound film of the light absorbing layer may be in the form of a layer covering the electron transporter. Specifically, in the case where the electron transporter is a porous structure including a porous film or the like, it may be a layer covering the electron transporter while filling the open pores of the electron transporter. . The thickness of the light absorbing layer may be 100 to 800 nm, but is not limited thereto.

The electron transporting body may be a porous layer (porous membrane) or a dense layer (density membrane) or a laminate in which a dense layer and a porous layer are stacked. The porous membrane may be a porous membrane including metal oxide particles. When the electron transporting body includes a porous metal oxide film, it is advantageous to place a dense metal oxide film on the lower portion of the porous film to prevent the light absorber filling the pores of the porous film from directly contacting the electrode. At this time, the metal oxide of the porous membrane and the metal oxide of the dense membrane may be the same or different materials. The metal oxide of the electron transporting body may be any metal oxide used for electron transfer in a conventional quantum dot-based solar cell, dye-sensitized solar cell, or perovskite-based solar cell. As a specific example, the metal oxide is titanium oxide, zinc oxide, indium oxide, tin oxide, tungsten oxide, niobium oxide, molybdenum oxide, magnesium oxide, barium oxide, zirconium oxide, strontium oxide, lanthanum oxide, vanadium oxide, aluminum Oxides, yttrium oxides, scandium oxides, samarium oxides, gallium oxides and strontium-titanium oxides, and mixtures thereof or mixtures thereof (including solids). The thickness of the porous metal oxide film may be 50 nm to 10 μm, specifically 50 nm to 1000 nm. In the case of the porous membrane, the specific surface area may be 10 to 100 m ² / g, and the average particle diameter of the metal oxide particles of the porous membrane may be 5 to 500 nm, but is not limited thereto. As described above, when the electron transporting body includes a porous metal oxide film, a dense metal oxide film may be further provided under the porous film. The dense film of the metal oxide serves to prevent contact between the light absorber and the electrode, and at the same time, it can serve to transfer electrons. The thickness of the dense film of the metal oxide may be substantially 10 nm or more, more substantially 10 nm to 100 nm, and even more substantially 50 nm to 100 nm.

A first electrode may be positioned under the electron transport body. In this case, it is needless to say that the first electrode may be located on the substrate as a support. The first substrate may be a rigid substrate or a flexible substrate. As a specific example, the first substrate may include a rigid substrate including a glass substrate or polyethylene terephthalate (PET); Polyethylene naphthalate (PEN): polyimide (PI); Polycarbonate (PC); Polypropylene (PP); Triacetyl cellulose (TAC); It may be a flexible (flexible) substrate including a polyether sulfone (PES). However, it goes without saying that the present invention cannot be limited by the type of substrate.

The first electrode may be any conductive electrode that is ohmic-bonded with the electron transporting body, and may be used as long as it is a material commonly used as an electrode material for a front electrode or a back electrode in a solar cell. In one non-limiting example, when the first electrode is an electrode material of the back electrode, the first electrode is one of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and combinations thereof. It may be a material selected above. In a non-limiting example, when the first electrode is a transparent electrode, the first electrode is a fluorine-containing tin oxide (FTO), an indium-doped tin oxide (ITO), ZnO, CNT (carbon Nanotubes), graphene (Graphene), or the like, or inorganic conductive electrodes, such as PEDOT: PSS, or organic conductive electrodes.

The hole transporter may be an organic hole transporter, an inorganic hole transporter, or a laminate thereof, and in particular, it may be manufactured by a solution process, and may be an organic hole transporter having excellent hole transport properties.

The organic hole transporter may include an organic hole transport material, specifically, a single molecule to a polymer organic hole transport material (hole conducting organic material). The organic hole transport material may be used as long as it is an organic hole transport material used in a conventional inorganic semiconductor-based solar cell or perovskite-based solar cell using an inorganic semiconductor quantum dot as a dye.

Non-limiting examples of organic hole transport materials, pentacene, coumarin 6, 3- (2-benzothiazolyl) -7- (diethylamino) coumarin), ZnPC (zinc phthalocyanine), CuPC (copper phthalocyanine) , TiOPC (titanium oxide phthalocyanine), Spiro-MeOTAD (2,2,2 ', 7,7,7'-tetrakis (N, N-di-p-methoxyphenyl amine) -9,9,9'-spirobi fluorene) , F16CuPC (copper (II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine), SubPc ( boron subphthalocyanine chloride), N3 (cis-di (thiocyanato) -bis (2,2'-bipyridyl-4,4'-dicarboxylic acid) -ruthenium (II)), P3HT (poly [3-hexylthiophene]), MDMO- PPV (poly [2-methoxy-5- (3 ', 7'-dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV (poly [2-methoxy-5- (2' '-ethylhexyloxy) -p -phenylene vinylene]), P3OT (poly (3-octyl thiophene)), POT (poly (octyl thiophene)), P3DT (poly (3-decyl thiophene)), P3DDT (poly (3-dodecyl thiophene), PPV (poly (p-phenylene vinylene)), TFB (poly (9,9'-dioctylfluorene-co-N- (4-butylphenyl) diphenyl amine), Polyaniline, Spiro-MeOTAD ([2,22 ' , 7,77′-tetrkis (N, N-di-p-methoxyphenyl amine) -9,9,9′-spirobi fluorine]), PCPDTBT (Poly [2,1,3-benzothiadiazole- 4,7-diyl [ 4,4-bis (2-ethylhexyl-4H-cyclopenta [2,1-b: 3,4-b '] dithiophene-2,6-diyl]], Si-PCPDTBT (poly [(4,4′-bis (2-ethylhexyl) dithieno [3,2-b: 2 ′, 3′-d] silole) -2,6-diyl-alt- (2,1,3-benzothiadiazole) -4,7-diyl]), PBDTTPD (poly ((4,8-diethylhexyloxyl) benzo ([1,2-b: 4,5-b '] dithiophene) -2,6-diyl) -alt-((5-octylthieno [3,4-c ] pyrrole-4,6-dione) -1,3-diyl)), PFDTBT (poly [2,7- (9- (2-ethylhexyl) -9-hexyl-fluorene) -alt-5,5- (4 ', 7, -di-2-thienyl-2', 1 ', 3'-benzothiadiazole)]), PFO-DBT (poly [2,7-.9,9- (dioctyl-fluorene) -alt-5, 5- (4 ', 7'-di-2-.thienyl-2', 1 ', 3'-benzothiadiazole)]), PSiFDTBT (poly [(2,7-dioctylsilafluorene) -2,7-diyl-alt- (4,7-bis (2-thienyl) -2,1,3-benzothiadiazole) -5,5′-diyl]), PSBTBT (poly [(4,4′-bis (2-ethylhexyl) dithieno [3, 2-b: 2 ′, 3′-d] silole) -2,6-diyl-alt- (2,1,3-benzothiadiazole) -4,7-diyl]), PCDTBT (Poly [[9- (1 -octylnonyl) -9H-carbazole-2,7-diyl] -2,5-thiophenediyl -2,1,3-benzothiadia zole-4,7-diyl-2,5-thiophenediyl]), PFB (poly (9,9′-dioctylfluorene-co-bis (N, N ′-(4, butylphenyl))) bis (N, N′-phenyl -1,4-phenylene) diamine), F8BT (poly (9,9′-dioctylfluorene-co-benzothiadiazole), PEDOT (poly (3,4-ethylenedioxythiophene)), PEDOT: PSS (poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate)), PTAA (poly (triarylamine)), poly (4-butylphenyl-diphenyl-amine), and one or more materials selected from these copolymers. As a non-limiting and specific example, the hole transporter may be a film of an organic hole transporting material, and the thickness of the film may be 10 nm to 500 nm. Typically, the organic material-based hole transporter has tertiary butyl pyridine (BPB), lithium bis (trifluoro methanesulfonyl) imide), and tris (2- (1H-pyrazol-1-yl) pyridine) cobalt to improve properties such as conductivity improvement. (III) and the like.

The solar cell may further include a second electrode positioned on the hole transporter, and the second electrode is a counter electrode of the first electrode. The second electrode may be any conductive electrode that is ohmic-bonded with the hole transporter, and may be used as long as it is a material commonly used as an electrode material for a front electrode or a back electrode in a solar cell. As a non-limiting example, when the second electrode is an electrode material of the back electrode, the second electrode is one of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and combinations thereof. It may be a material selected above. In a non-limiting example, when the second electrode is a transparent electrode, the second electrode is fluorine-containing tin oxide (FTO), indium-doped tin oxide (ITO), ZnO, CNT (carbon Nanotube), graphene (Graphene), or an inorganic conductive electrode, and may be an organic conductive electrode such as PEDOT: PSS.

The present invention includes a method of manufacturing the above-described perovskite solar cell. In detailing the manufacturing method of the perovskite solar cell, the material of the perovskite compound film, the crystallinity of the perovskite compound film, the orientation of the perovskite compound film, the structure of the perovskite compound film, the electron transporter and The material and structure of the hole carrier, the materials of the first electrode and the second electrode, etc. are similar or the same as described above in the perovskite solar cell. Accordingly, the method for manufacturing a perovskite solar cell according to the present invention includes all the contents described in the perovskite solar cell described above.

A method of manufacturing a perovskite solar cell according to the present invention comprises the steps of: a) forming an electron carrier on a first electrode; b) C6 or higher normal alkylammonium halide on the electron transporter; An organic halide which is a halide of a monovalent organic ion constituting an organometal halide having a perovskite structure; And forming a light absorbing layer by applying a liquid containing a divalent metal halide (hereinafter, an organic capping agent-perovskite solution); And c) sequentially forming a hole transporter and a second electrode on the light absorbing layer.

The organic capping agent-perovskite solution contains an alkylammonium halide, an organic halide, and a metal halide. It is also interpreted that the organic capping agent-perovskite solution contains an alkylammonium metal halide and a perovskite compound. Can be. This is because the state in which the alkyl ammonium metal halide is dissolved corresponds to the state in which the alkyl ammonium halide and metal halide are dissolved, and the state in which the perovskite compound is dissolved corresponds to the state in which the organic halide and metal halide are dissolved.

Further, that the organic capping agent-perovskite solution contains an alkylammonium halide, an organic halide, and a metal halide can also be interpreted as containing an alkylammonium ion source and a perovskite compound. Alternatively, the organic It can also be interpreted as containing a monomolecular source and a perovskite compound.

The alkylammonium halide may be a C6 or higher normal alkylammonium halide, preferably a C6 to C12 normal alkylammonium halide, more preferably a C8 to C12 normal alkylammonium halide, and even more preferably a C8 to C10 normal alkylammonium halide. You can.

As described above, the manufacturing method according to the present invention does not require a separate additional process or highly controlled process conditions, and uses a conventionally established solution application method as it is, but instead of a solution in which a conventional perovskite compound is dissolved. , An organic capping agent-a light-absorbing layer comprising a one-dimensional alkylammonium metal halide which is located on the grain and grain boundary of the perovskite compound only by using the perovskite solution, or Perovskite compound grain (grain) and the grain boundary (grain boundary) located in the light absorbing layer including an organic monomolecular film surrounding the grain, or perovskite compound grain (grain) and located in the grain boundary (grain) A light absorbing layer including a grain boundary layer that is non-crystalline and contains a normal alkylammonium ion having a C6 or higher covering the grains may be prepared. You can.

The content of the alkyl ammonium metal halide surrounding the perovskite grain can be controlled by the content of the alkyl ammonium halide in the organic capping agent-perovskite solution. Accordingly, the ratio of the number of moles of the metal halide to the number of moles of the alkylammonium halide in the organic capping agent-perovskite solution may be 100: 0.5 to 5, preferably 0.5 to 4, and more preferably 1 to 4. Thereby, the light absorbing layer containing 0.5 to 5 mol% of alkyl ammonium metal halide, preferably 0.5 to 4 mol%, more preferably 1 to 4 mol%, in other words, 0.5 to 5 mol% of organic single molecule, preferably Is a light absorbing layer containing 0.5 to 4 mol%, more preferably 1 to 4 mol%, or in other words, 0.5 to 5 mol%, preferably 0.5 to 4 mol%, more preferably 1 to 4 mol% of alkylammonium ions. A light absorbing layer containing can be prepared.

In addition, the organic capping agent-perovskite solution, at least, a mole number of organic halides capable of forming a perovskite compound by combining with a mole number of metal halides minus the number of moles of the alkyl ammonium halide minus the number of moles of metal halide in the solution. It may contain. That is, the organic capping agent-perovskite solution may contain at least M1-M2 moles of organic halides minus M2, which is moles of alkyl ammonium halide, from M1 which is the moles of metal halide. As a practical example, the ratio of the number of moles of the metal halide to the number of moles of the alkyl ammonium halide: the number of moles of the organic halide in the organic capping agent-perovskite solution may be 100: 0.5 to 5:95 to 99.5.

The step (a) of forming the electron transporting body may include forming a stacked body on which a metal oxide porous film is stacked on a first electrode, a dense metal oxide film, a porous metal oxide film, or a dense metal oxide film. Specifically, the metal oxide dense film may be manufactured by forming a dense film of metal oxide through a deposition process such as physical vapor deposition or chemical vapor deposition, and the porous metal oxide membrane is coated with a slurry containing metal oxide particles, and the applied slurry layer It can be prepared by drying and heat treatment. The slurry can be selected from screen printing, spin coating, bar coating, gravure coating, blade coating, and roll coating. It can be performed by any one or more methods, but is not limited thereto. The average particle size of the metal oxide particles may be 5 to 500 nm, and the heat treatment may be performed in air at 200 to 600 ° C, but is not limited thereto. When forming the metal oxide porous film, the thickness of the metal oxide porous film produced by drying the coated slurry after being dried is, for example, 50 nm to 10 μm, more preferably 50 nm to 5 μm, even more preferably 50 nm It may be from 1 μm, but is not limited thereto. A laminate in which a metal oxide porous film-like metal oxide porous film is stacked can be produced by forming a metal oxide dense film and then forming a metal oxide porous film on a metal oxide dense film, a method of manufacturing a metal oxide dense film and a metal oxide porous film. The manufacturing method is the same or similar to that described above.

The organic capping agent-perovskite solution of step b), b1) the alkylammonium halide, the organic halide and the metal halide are added to the first solvent and heated to obtain a perovskite powder modified with an alkylammonium metal halide. step; And dissolving the perovskite powder modified with an alkylammonium metal halide in a second solvent to prepare an organic capping agent-perovskite solution. At this time, the alkylammonium halide, the organic halide, and the metal halide in step b1) may satisfy the above-described molar ratio in the organic capping agent-perovskite solution.

Specifically, in step b1), the alkyl ammonium halide and the metal halide satisfying the stoichiometric ratio of the alkylammonium metal halide in the first solvent, and the organic halide satisfying the stoichiometric ratio of the perovskite compound (ex. AX (chemical formula) A and X specified in 1)) and metal halide (MX ₂ (M and X defined in Chemical Formula 1)) may be added.

In addition, as described above in the solar cell, when the metal and halogen of the alkylammonium metal halide are the same as the metal and halogen of the perovskite, the perovskite modified with the alkylammonium metal halide obtained in step b1) It goes without saying that the powder may be damaged by perovskite powder modified with an alkylammonium ion or perovskite powder modified with an organic monomolecular film.

The first solvent and the second solvent are independent of each other and may be any non-aqueous polar organic solvent used as a solvent for dissolving the perovskite compound. In one embodiment, the non-aqueous polar organic solvent is gamma-butyrolactone, formamide, N, N-dimethylformamide, diformamide, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, diethylene glycol, 1 -Methyl-2-pyrrolidone, N, N-dimethylacetamide, acetone, α-terpineol, β-terpineol, dihydro terpineol, 2-methoxy ethanol, acetylacetone, methanol, ethanol , Propanol, isopropanol, butanol, pentanol, hexanol, ketone, methyl isobutyl ketone, or the like, but is not limited thereto.

The heating in step b1) may be heated to a temperature of 0.7 to 0.85T _b based on the boiling point (T _b ) of the first solvent, but is not limited thereto.

In step b2), the organic capping agent-perovskite solution may contain a perovskite powder modified with an alkylammonium metal halide at a molar concentration of 0.9 mM to 1.6 mM, but is not limited thereto, and the light absorbing layer Needless to say, the concentration of the organic capping agent-perovskite solution may be appropriately changed by the method of forming the sphere and the use of the sphere solar cell.

The step (b) of forming the light absorbing layer using the organic capping agent-perovskite solution) may be performed using a solution coating method commonly used in a conventional perovskite solar cell. However, in order for the light absorbing layer to be manufactured with a dense layer having a smooth surface, the light absorbing layer forming step is a solvent-nonsolvent coating method (2-step coating method) sequentially applying an organic capping agent-perovskite solution and a non-solvent. ). The solvent-non-solvent coating method may be performed with reference to Korean Patent Registration No. 10-1547877 or No. 10-1547870. Specifically, step b) may include the step of sequentially applying a non-solvent of an organic capping agent-perovskite solution and a perovskite compound onto the electron transporter; and may include a non-solvent of the perovskite compound. And non-polar organic solvents such as pentane, hexene, cyclohexene, 1,4-dioxene, benzene, toluene, triethyl amine, chlorobenzene, ethylamine, ethyl ether, and chloroform. The application of step b) may be carried out by an application method commonly used for application in liquid or dispersed phases, for example, dip coating, spin coating, casting, spraying, screen printing, inkjet printing, electrostatic hydraulic printing, micro contact Printing, imprinting, gravure printing, reverse offset printing or gravure offset printing, but are not limited thereto. In addition, if necessary, heat treatment may be performed at 80 to 150 ° C. after application of step b), but the present invention is not limited by the presence or absence of heat treatment or heat treatment conditions.

However, in the present invention, the method for forming the light absorbing layer (i.e., step b)) is not limited to the application of a liquid containing an alkylammonium halide, an organic halide, and a metal halide, and a liquid containing a perovskite compound The light absorbing layer may be formed by sequentially applying (first liquid) and a liquid containing an alkylammonium metal halide (second liquid).

That is, the manufacturing method according to the present invention according to another aspect includes a) forming an electron carrier on a first electrode; b) forming a light absorbing layer by sequentially applying a liquid containing a perovskite compound on the electron transporter and a liquid containing an alkylammonium metal halide (alkylammonium halide and divalent metal halide); And c) sequentially forming a hole transporter and a second electrode on the light absorbing layer. However, when sequentially applying the first liquid and the second liquid, it is advantageous that the second liquid is applied before the solvent of the first liquid applied is volatilized, and in this case, the organic capping agent-perovskite solution of a single liquid A light absorbing layer having substantially the same characteristics and structure as when applied may be formed. Application of the first and second solutions is independent of each other by dip coating, spin coating, casting, spraying, screen printing, inkjet printing, electrostatic hydraulic printing, micro contact printing, imprinting, gravure printing, reverse offset printing or gravure It may be performed by offset printing, but is not limited thereto.

After forming the light absorbing layer, a step of forming a hole transporter and a second electrode may be performed on the light absorbing layer. The step of forming a hole transporter may be performed by applying and drying an organic hole transport solution, which is a solution containing an organic hole transport material, so as to cover the upper portion of the light absorbing layer. The solvent used for forming the hole transporter is an organic hole transporting material, and any solvent that does not react with the light absorbing layer may be used. For example, the solvent used for forming the hole transporter may be a non-polar solvent, and as a practical example, toluene, chloroform, chlorobenzene, dichlorobenzene, anisole ), Xylene and any one or two or more selected from hydrocarbon-based solvents having 6 to 14 carbon atoms.

It is sufficient if the second electrode is formed through a conventional metal deposition method used in a semiconductor process. For example, the second electrode may be formed through a vapor deposition process such as physical vapor deposition or chemical vapor deposition, and may be specifically formed by thermal vapor deposition.

(Production example)

Synthesis of n-octylammonium iodide (OAI)

A mixture of octylamine (37.6 mL, 227 mmol) and 5 mL of ethanol in an ice bath was stirred vigorously and a drop of an aqueous hydroiodic acid solution (HI, 30 mL, 227 mmol) was added, followed by stirring for an additional 2 hours. The solvent was then removed under vacuum, and the precipitate was dissolved in ethanol and recrystallized from diethyl ether. The white flakes of n-octylammonium iodide (OAI) obtained by the recrystallization process were dried overnight at 60 ° C under vacuum.

Methylammonium iodide (MAI), butylammonium iodide (BAI) in the same way as octylammonium iodide production, except that methylamine, butylamine or phenethylamine was used instead of octylamine Or phenethylammonium iodide (PEAI) was prepared.

(Example)

As shown in Table 1, by adding MAI, PbI ₂ and OAI to 2-methoxyethanol, octylammonium (OA) is 3.3 mol% (Example 1), 4.9 mol% (Example 2), or 9.5 mol% ( Example 3) A solution was prepared and stirred at 100 ° C. for 30 minutes to form a precipitate. The formed precipitate was collected by suction filtration and dried under vacuum overnight to prepare an otylammonium modified perovskite powder.

(Table 1)

Fluorine-doped tin oxide (FTO) coated glass (Pilkington, TEC8, FTO substrate) was cleaned in an ultrasonic bath for 30 minutes using detergent, acetone and ethanol.

A 50 nm thick TiO ₂ dense film (bl-TiO ₂ ) was prepared on the washed FTO substrate by spray pyrolysis. Spray pyrolysis was performed by spraying a solution of titanium diisopropoxide bis (acetylacetonate): ethanol (1:10 v / v%) onto an FTO substrate at 450 ° C.

After spin coating the TiO ₂ paste having an average particle size of 50 nm on the FTO substrate on which the TiO ₂ dense film was formed for 50 seconds at 1500 rpm, the substrate was annealed at 500 ° C. for 1 hour to form a 200 nm thick porous TiO ₂ layer ( mp-TiO ₂ ) was prepared.

 NN-Dimethyl formamide (DMF): 0.7 g of octylammonium modified perovskite powder per 1 ml of a mixed solvent in which dimethyl sulfoxide (DMSO) is mixed at a volume ratio of 4: 1 is added and stirred at 60 ° C. After preparing the solution, an organic capping agent-perovskite solution was prepared by filtering the solution prepared using a PTFE (Polytetrafluoroethylene) syringe filter (0.2 μm).

The organic capping agent-perovskite solution filtered on the substrate on which the porous TiO ₂ layer was formed was spin coated for 15 seconds at 1000 rpm (a rising speed of 300 rpm / sec) and subsequently 5000 rpm (a rising speed of 1300 rpm / sec) ) Spin coating was performed for 20 seconds, and spin coating was performed by injecting 1 mL of toluene at a time when spin coating at 5000 rpm was performed for 10 seconds. Thereafter, the perovskite compound film formed by spin coating was heat-treated on a hot plate at 100 ° C. for 10 minutes to prepare a light absorbing layer having a thickness of about 300 nm.

Poly (bis (4-phenyl) (2,4,6-trimethylphenyl) amine) (PTAA; poly (bis (4-phenyl) (2,4,6-trimethylphenyl) amine)) to form a hole transport layer) 7.5 μL of acetic nitrile solution (170 mg / mL) and 7.5 μL of lithium bis (trifluoromethanesulfonyl) imide (Li-TFSI) in a solution (10 mg PTAA in 1 mL toluene) The mixed solution of 4-Lt 4-butylt-pyridine (tBP) was spin-coated on the substrate on which the light absorbing layer was formed at 3000 rpm for 30 seconds. Finally, a gold electrode was deposited on the hole transport layer using a thermal evaporator to form a counter electrode.

(Comparative example)

Performed in the same manner as in Example, without preparing OAI into 2-methoxyethanol, to prepare unmodified perovskite powder (Comparative Example 1, 0 mol% OA mixed perovskite in Table 1), or 2-methoxyethanol BAI or PEAI synthesized in Preparation Example instead of OAI was added to prepare butylammonium modified perovskite powder (Comparative Example 2) or phenethylammonium modified perovskite powder (Comparative Example 3), and an organic capping agent- Examples except for using unmodified perovskite powder, butylammonium modified perovskite powder or phenethylammonium modified perovskite powder instead of octylammonium modified perovskite powder in preparing perovskite solution Perovskite solar cells were manufactured in the same manner as.

The shape of the light absorbing layer prepared in Examples and Comparative Examples was observed using a scanning electron microscope (Tescan Mira 3 LMU FEG) operated at 5 kV.

The crystal structure was analyzed using an X-ray diffractometer (Rigaku SmartLab) .Grading incidence wide angle X-ray scattering (GIWAXS) measurements were performed using Pohang Accelerator Laboratory (PAL) beamline 6D (wavelength: 1.0688 Å). Became. When measuring GIWAXS, the incident angle was 0.3 ° and the sample-detector distance was about 246.4 mm.

 Structural transition behavior of the perovskite powder was performed using a differential scanning calorimeter (TA Instruments Q200), nitrogen at 50 ml / min, in a temperature range from 30 ° C to 120 ° C with an ascent rate of 5 ° C / min It was carried out at a flow rate.

Thermal gravimetric analysis (TGA) for perovskite powders was performed at 30 ° C. to 500 ° C. with a rise rate of 10 ° C./min in air, using TA Instruments Q500.

Time-resolved photoluminescence (TRPL) measurements were performed using a fluorescence spectrometer (Edinburgh Instruments, FL920). The TRPL attenuation profile was calculated through the individual maximum photoluminescence (PL) emission for samples where the maximum average power was excited at a wavelength of 470 nm at 5 mW. The photoluminescence emission decay curve is Y = A1exp (-t / τ1) + A2exp (-t / τ2) (Y is emission intensity over time, A1 and A2 are relative amplitudes, τ1 and τ2 was fit using the equation of fit PL decay time). This equation describes the charge carrier dynamics by a combination of non-radiative recombination at the defect site and radiation recombination at the bulk perovskite film, assigned τ1 and τ2 as fast and slow components, respectively.

Current density-voltage (JV) properties were measured using a solar simulator (Newport, Oriel Sol3A Class AAA) with an AM 1.5 and 100 mWcm ^-2 irradiation intensity and a Keithley 2420 source meter. The active area was 0.096 cm ² . The JV scan was performed with a delay time of 100 ms and 10 mV steps in the reverse (V _oc- > V _o ) and forward (V _o- > V _oc ) directions. External quantum efficiency (EQE) was measured using an IQE 200B system (ORIEL Instruments) under 100W xenon lamp irradiation.

The thermal stability test was performed by heating an unencapsulated, bare perovskite solar cell in the manufactured state to 85 ° C. in the air with light blocked. The photo-stability test is carried out by inserting a perovskite solar cell as it is manufactured into a nitrogen-filled chamber and using a solar simulator (Newport, Oriel Sol3A Class AAA) having an irradiation intensity of 1.5 and 100 mWcm ^-2 . Was performed by irradiating unblocked continuous light. The moisture stability test was performed by storing the unencapsulated perovskite solar cell device in a constant temperature and humidity chamber set at 25 ° C and 85% RH.

1 is Example 1 (3.3 mol% OA mixed perovskite in Table 1), 2 (4.9 mol% OA mixed perovskite in Table 1), 3 (9.5 mol% OA mixed perovskite in Table 1) and Comparative Example 1 (Table 1) It is a diagram showing the results of differential scanning calorimetry (DSC) measurement of perovskite powder used in preparing the organic capping agent-perovskite solution at 0 mol% OA mixed perovskite). In FIG. 1, the powder result of Comparative Example 1 having an octylammonium (hereinafter, OA) content of 0 mol% is black, and the powder result of Example 1 having an OA content of 3.3 mol% is blue, and the OA content is 4.9 mol%. The powder result of Example 2 is shown in red, and the powder result of Example 3 with an OA content of 9.5 mol% is shown in green. As can be seen in FIG. 1, the phase transition temperature from the tetragonal structure to the cubic structure occurred at about 58.8 ° C. and 56.6 ° C., respectively, during the heating and cooling process, which is substantially the same as the pure perovskite compound having 0 mol% OA. same. The results of the thermal analysis show that the state modified with the octylammonium cation does not affect the crystal phase transition of the perovskite compound.

2 is octylammonium modified perovskite used for preparation in Comparative Example 1 (0% OA), Example 1 (3.3% OA), Example 2 (4.9% OA) and Example 3 (9.5% OA). It shows the FTIR (Fourier transform infrared spectroscopy) spectrum of the powder, and for comparison, the spectra of octylammonium iodide (OAI in FIG. 2) and methylammonium iodide (MAI in FIG. 2) are shown together. It is done.

As can be seen in Figure 2, at 2858 cm ^-1 and 2927cm ^-1 of -CH ₂ symmetric and asymmetric mode vibrations it can be seen that the peaks are present, that the peak at 2958 cm ^-1 of the symmetric oscillation mode exists -CH ₃ Can be seen. In addition, it can be seen that the intensity of the peak increases as the content of octylammonium increases. It can be seen from the FTIR spectrum results of FIG. 2 that perovskite powder modified with octylammonium is prepared.

3 is an X-ray diffraction result of the light absorbing layers prepared in Examples 1, 2, 3 and Comparative Example 1 (FIG. 3 (a)) and a scanning electron microscope photograph (Fig. 3 (b)) observing the surface of the light absorbing layer. , Scale bar = 500nm), GIWAXS measurement result (FIG. 3 (c)), charge carrier recombination lifetime measured by time correlated single photon counting (TCSPC) (FIG. 3 (d)) and X- by (110) plane FWHM of the line diffraction peak, diffraction peak intensity and PL life time (FIG. 3 (e)). 3, 0%, 3.3%, 4.9% and 9.5% are light absorbing layers prepared in Comparative Example 1, light absorbing layers prepared in Example 1, light absorbing layers prepared in Example 2, and light absorbing layers prepared in Example 3 It means the result of, and the content (mol%) of octylammonium cation contained in the light absorbing layer.

3 (a) and (e), when looking at the FWHM of the XRD peak at about 2θ = 14.3 ° corresponding to the (110) plane, the OA content is as low as 3.3 mol% and 4.9 mol%, It can be seen that FWHM is 0.15 °, which is narrower than 0.17 °, which is FWHM of the pure perovskite film, and when the OA content is increased to 9.5 mol%, FWHM is rather widened to about 0.21 °. The area of FWHM in the high OA content region means that the crystal grain size and crystallinity of the perovskite film are reduced, suggesting that the crystal growth of perovskite is suppressed when a large amount of OA is introduced.

These results are consistent with the scanning electron microscope observation results of FIG. 3 (b), and the particle size of the light absorbing layer with a high OA content (9.5 mol%) is a light absorbing layer of pure perovskite (Comparative Example 1) or a low OA content. (3.3 mol% and 4.9 mol%) compared to the light absorbing layer having a decrease. In addition, in the case of the light absorbing layer having a low OA content (3.3 mol% and 4.9 mol%), it can be seen that grains having a size almost equal to that of the pure perovskite light absorbing layer (200-500 nm level) are formed. It can be confirmed that the light absorbing layer of the dense film which is hardly present is formed.

In addition, looking at the intensity change of the (110) diffraction peaks of FIGS. 3 (a) and 3 (e), in addition to the change in grain size due to the addition of OA cations, the (110) of the light absorbing layers having OA contents of 3.3 and 4.9 mol% It can be seen that the diffraction peak intensity was 3.9 and 2.7 times higher than the OA-free film (Comparative Example 1). It can be seen that as the light absorbing layer thicknesses of all the produced solar cell samples were substantially the same, the increase in XRD peak intensity increased the orientation of the (110) plane in the OA modified perovskite film.

This increase in the preferred orientation (preferred orientation) can also be seen through the GIWAXS measurement results of Figure 3 (c). Figure 3 (c) shows a scattering ring at q = 1Å ^-1 corresponding to the (110) plane of the perovskite structure. As can be seen from FIG. 3 (c), it can be seen that the OA-free film (Comparative Example 1) exhibits a uniform intensity distribution along the azimuth angle at q = 1 mm ⁻¹ , so that there is almost no orientation in the crystal direction. On the other hand, if the OA content is low at 3.3 and 4.9 mol%, it can be seen that it has a very strong scattering strength at an azimuth of 90 °, which means that the crystal plane is highly oriented parallel to the substrate, thereby improving charge transport. It means to have characteristics. On the other hand, it can be seen that at a high OA content of 9.5 mol%, the crystallinity is greatly reduced and the preferred orientation of the (110) plane is also greatly reduced.

3 (d) and 3 (e), the charge recombination of 157nsec and 118nsec is much longer than 37nsec of the OA-free film (Comparative Example 1) when the OA content is low at 3.3 and 4.9 mol%. It can be seen that it has a life time, and when it has an OA content of 9.5 mol%, it can be seen that it has a charge recombination life time of 70 nsec. The improved charge recombination life time means a significant reduction in non-radiative recombination due to the highly preferential orientation.

Figure 4 is a schematic diagram showing the structure of the perovskite thin film along the length of the alkyl chain, Figure 4 (a) is an octylammonium (OA) modified perovskite thin film, Figure 4 (b) is butyl ammonium (BA ) Modified perovskite membrane and phenethylammonium (PEA) modified perovskite membrane, FIG. 4 (c) is a schematic view of a pure perovskite membrane, and FIGS. 4 (d) to (g) are 50 mol% OA Perovskite film containing (Fig. 4 (d)), perovskite film containing 50 mol% PEA (Fig. 4 (e)), perovskite film containing 50 mol% BA (Fig. 4 (f)) and This is a diagram showing the X-ray diffraction results of a pure perovskite film. In the X-ray diffraction results of FIG. 4, the diffraction peaks of 3.8 °, 6.8 °, 10.3 °, and 12.0 ° are formed in a BA or PEA modified perovskite, and a layered perovskite structure is formed by BA or PEA. It is a peak appearing according to and is a diffraction peak by (020), (040), (060), and (080) planes of the number of layers (n) 3 in the layered perovskite structure. However, as shown in FIG. 4 (d), it can be seen that in the case of OA-modified perovskite, a diffraction pattern substantially the same as that of pure perovskite is detected. Through the DSC analysis results of FIG. 1 and the XRD, GIWAXS and PL spectral characteristics of FIG. 3, and the X-ray diffraction analysis results of FIG. 4, as shown in FIGS. 4 (a) to (c), a long normal alkyl chain When the octylammonium cation having is introduced, the layered perovskite structure as shown in Fig. 4 (b) is not formed, and the octylammonium cation is located in the grain boundary and surface defects, and individual three-dimensional perovskites It can be seen that it encloses each of the skye grains and causes a high degree of preferential orientation. This high degree of preferential orientation results in van der Waals forces between long alkyl chains, hydrogen bonds between ammonium functional groups and perovskite inorganic skeletons, and adhesion of the alkyl chain to the metal-halogen (metal-halogen of perovskite) termination surface. It can be interpreted as derived from. As shown in the stability test results described below, such van der Waals forces, hydrogen bonding and adsorption can significantly improve the stability of the solar cell.

Figure 5 is Comparative Example 1 (0% OA, Figure 5 (a), Figure 5 (d)), Example 1 (3.3%, OA Figure 5 (b), Figure 5 (e)) and Example 3 (9.5 % OA, Cross sectional high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) observation photo (scale bar = 20 nm) and HAADF-STEM of the light absorbing layer prepared in FIGS. 5 (c) and 5 (f)) FIG. 5 (g) shows the EDX element mapping results for Pb, I, and C in the red line across the grain boundary in the observation photograph, and FIG. 5 (g) shows BF-STEM (Bright- of the light absorbing layer prepared in Example 1). Field scanning transmission electron microscopy. As can be seen in FIG. 5, it can be directly confirmed that the width of the grain boundary is wider than that of the pure perovskite compound as octyl ammonium is introduced at the grain boundary, and the organic material of octyl ammonium is located at the grain boundary through FIG. 5 (g). Can be directly checked.

Figure 6 (a) is a view showing a cross-sectional scanning electron microscope observation photo (scale bar = 500nm) of a solar cell (Example 1) equipped with a light absorption layer containing 3.3 mol% OA, Figure 6 (b) 20 examples prepared in Comparative Example 1 (OA = 0 mol%), Example 1 (OA = 3.3 mol%), Example 2 (OA = 4.9 mol%), and Example 3 (OA = 9.5 mol%), respectively. FIG. 6 (c) is a diagram showing the current density-voltage graph of the solar cells of Comparative Example 1 and Example 1, and FIG. 6 (d) is an example. 1 (3.3 mol% OA) is a diagram showing the external quantum efficiency (EQE) spectrum of a solar cell manufactured in FIG. 6 (e) is 100 mW / cm ² of the solar cell manufactured in Example 1 (3.3 mol% OA) It shows the power output stabilized at 1SUN and 0.92V conditions.

Looking at the PCE histogram showing the statistical distribution of FIG. 6 (b), the average efficiency of the solar cell of Comparative Example 1 that does not contain OA is 17.4%, and low content (3.3 and 4.9 mol%) of OA is introduced and the solar cell is introduced. It can be seen that the performance is greatly improved, and in particular, when it contains 3.3 mol% of OA, the maximum efficiency is 20.6%, and it can be seen that a significant efficiency improvement of up to 18% compared to the conventional solar cell according to Comparative Example 1 occurs. have. This improvement in efficiency can be interpreted as a result of both a high priority orientation and a decrease in non-radiative recombination in the light absorbing layer, and an average in the case of a solar cell equipped with a light absorbing layer containing 9.5 mol% OA having poor orientation and poor crystallinity The reduction in efficiency to 16.7% is also a result of supporting this.

As shown in Table 2, which shows the current density-voltage characteristic results of the solar cells of Comparative Example 1 and Example 1 of FIG. 6 (c) and the solar cell characteristics (based on maximum efficiency) of Comparative Example 1 and Example 1, respectively. , In the case of a perovskite solar cell in which a small amount of OA is introduced, it can be seen that the short circuit current density (Jsc), fill factor (FF), and open circuit voltage (Voc) all increase. The increase in open circuit voltage and fill factor is due to the decrease in non-radiative charge carrier recombination due to the strong preferential orientation, and the increase in short-circuit current density is also due to the excellent charge transport properties due to the strong preferential orientation.

(Table 2)

The cumulative current density (integrated Jsc) value calculated from the external quantum efficiency graph of FIG. 6 (d) is 21.7mAcm ^-2 , which is the Jsc (22.6 mA cm ^-2 ) measured from the JV curve of FIG. 6 (c). It can be seen that there is a difference of approximately 4.0%, and it is confirmed that hysteresis during forward and reverse scans is also greatly reduced by OA modification. In order to exclude the hysteresis behavior in reverse and forward scanning and evaluate the photovoltaic efficiency, the stabilized PCE was measured at a constant voltage of 0.92 V corresponding to the approximately maximum power point in the JV curve, as shown in FIG. 6 (e), The stabilized PCE value was confirmed to be 20.1%.

7 is a thermal stability test results performed at 85 ℃ of the solar cell prepared in Comparative Example 1 and the solar cell prepared in Example 1 (Fig. 7 (a)), 25 ℃ relative humidity (RH) performed at 65% Humidity stability test result (FIG. 7 (b)), a diagram showing a light stability test result (FIG. 7 (c)) performed by irradiating light with no UV filtering under AM 1.5G 100 mW / cm ² , Scanning electron micrographs and schematic diagrams of the surface immediately after preparation of the light absorbing layer prepared in Example 1 and the surface of the light absorbing layer ((FIG. 7 (d)) after being exposed at 85 ° C. for 4 days), light prepared in Comparative Example 1 Scanning Electron Micrograph and Schematic View of the Surface Immediately After Preparation of the Absorption Layer and the Surface of the Light Absorption Layer ((FIG. 7 (e)) after 4 days of exposure at 85 ° C.) Scanning electron micrograph and schematic view of the surface of the light absorbing layer ((FIG. 7 (f)) after electron beam irradiation for seconds) , A view showing a scanning electron microscope photograph and a schematic view of the surface of the light absorbing layer prepared in Comparative Example 1 immediately after manufacture and the surface of the light absorbing layer ((FIG. 7 (g)) after electron beam irradiation for 60 seconds). The photoelectric conversion efficiency, short circuit current density, open circuit voltage and fill factor were normalized to the values immediately after manufacturing.

As can be seen in Figure 7 (a), in the case of the conventional perovskite solar cell prepared in Comparative Example 1, it can be seen that the efficiency at 432 hours is reduced to about 40.0% of the initial efficiency. However, it can be confirmed that the OA-modified perovskite solar cell has excellent thermal stability that maintains an initial efficiency of 87.5% at the same time point. Furthermore, it can be seen that 80.0% or more of the initial efficiency is maintained at the time of 768 hours of stability test, and 80.0% or more of the initial efficiency is maintained at the time of 768 hours under the severe thermal conditions of 85 ° C in the air without encapsulation. Stability is an extremely good long-term stability that has not been reported to date. In addition, as can be seen through the scanning electron microscope observation picture of FIG. 7, it can be confirmed that in the case of the conventional perovskite compound film, the film is deteriorated by heat or an electron beam, and particularly, the deterioration starts at the grain boundary. However, in the case of the perovskite compound film according to the present invention, it can be confirmed that the film does not deteriorate even after irradiation with heat or electron beam, and it can be confirmed that OA present at the grain boundary serves as a protective coating material for heat.

In addition, water stability evaluation of the perovskite solar cell device was performed at room temperature and 65% relative humidity. In addition to the excellent heat resistance, as can be seen in Figure 7 (b), the perovskite compound membrane prepared in Comparative Example 1, the relative humidity (RH) 65% and severe deterioration occurred at 25 ℃. It can be interpreted that methyl ammonium having strong hygroscopicity reacts with moisture to accelerate the decomposition of perovskite. However, it can be seen that the perovskite compound membrane according to an embodiment of the present invention has excellent humidity stability that maintains 90% or more of the initial efficiency even during a test for 430 hours. This improved humidity stability can be interpreted as exhibiting strong resistance to moisture due to the hydrophobicity of the alkyl chain located at the grain boundary.

Figure 8 (a) is a solar cell prepared in Example 1, Comparative Example 1 (0mol% OA), Comparative Example 2 (3.3mol% BA) and Comparative Example 3 (3.3mol% PEA) thermal of the solar cell prepared in It is a diagram showing the measurement of stability, and FIG. 8 (b) is a diagram showing the measurement of thermal stability of the solar cell manufactured in Example 1, Example 2 and Example 3. As can be seen in Figure 8, it can be seen that the solar cells prepared in Comparative Example 2 and Comparative Example 3 have almost similar thermal stability to each other, and thermal stability is relatively maintained by maintaining about 61% of the initial efficiency at 768 hours. It can be seen that it falls.

The excellent thermal stability of the solar cell produced in the Examples is that each of the perovskite grains has strong interactions due to van der Waals forces between the long alkyl chains of OA, hydrogen bonds between the ammonium functional groups and perovskite inorganic skeletons, and alkyl. It can be interpreted as being due to the adhesion of the chain to the metal-halogen (perovskite metal-halogen) termination surface, and also to the low volatility (excellent heat resistance) of the OA itself.

In addition, in the case of the conventional perovskite solar cell prepared in Comparative Example 1 through the light stability test results (FIG. 7 (c)) performed at room temperature AM1.5G without using a UV filter in a nitrogen atmosphere 3 It can be seen that the efficiency decreases rapidly to 20% of the initial value in only a short time. However, it can be seen that in the case of the perovskite solar cell manufactured in the example, 70% of the initial efficiency is maintained even after 75 hours have passed. It can be seen that this excellent light stability is caused by the OA surrounding the perovskite grain forming a barrier, protecting each perovskite grain from the external environment, and furthermore, the alkyl chain is a metal-halogen ( By attaching to the metal-halogen) termination surface of the perovskite, it can be seen that the material decomposition of the perovskite is effectively prevented.

As is known, decomposition by light occurs when electrons are extracted from halogen anions by TiO ₂ and halogens are reduced to halogen molecules. In addition, at the interface between TiO ₂ and perovskite compound, light holes and oxygen react. Caused by the formation of deep traps. However, in the perovskite compound film according to an embodiment of the present invention, as the organic single molecule surrounds not only the grain boundary but also the entire grain, an organic monomolecular film exists between the perovskite grain and TiO ₂ to significantly improve light stability. Can be improved.

As described above, in the present invention, it has been described by specific matters and limited embodiments and drawings, which are provided only to help the overall understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Various modifications and variations can be made by those skilled in the art.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and should not be determined, and all claims that are equivalent or equivalent to the scope of the claims as well as the claims to be described later belong to the scope of the spirit of the invention. .

Claims (22)

The perovskite compound perovskite structure is a perovskite compound grain and a grain boundary located at a grain boundary, covering the grain, including C6 or higher normal alkylammonium ions, and including a non-crystalline grain boundary layer The perovskite compound film; includes a light absorbing layer, the perovskite compound film perovskite solar cell satisfies the following relational expression 1.
(Relationship 1)
I (110) / I ₀ (110) ≥ 2
(In the relational expression 1, I (110) is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the perovskite compound film, and I ₀ (110) is the perovskite The intensity of the diffraction peak by the (110) plane in the X-ray diffraction measurement using Cu-Kα rays of the reference light-absorbing layer made of polycrystals of the same perovskite compound grain as the compound film) According to claim 1,
The ammonium group of the normal alkylammonium ion is a perovskite solar cell bonded to the metal-halogen inorganic skeleton of the perovskite compound grain. According to claim 1,
The alkyl of the normal alkylammonium ion is a C8 to C12 normal alkyl perovskite solar cell. The perovskite compound perovskite compound is a perovskite compound grain located on a grain and a grain boundary, and includes a perovskite compound film including an organic monomolecular film surrounding the grain as a light absorbing layer, The perovskite compound membrane is a perovskite solar cell that satisfies the following relationship (1).
(Relationship 1)
I (110) / I ₀ (110) ≥ 2
(In the relational expression 1, I (110) is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the perovskite compound film, and I ₀ (110) is the perovskite The intensity of the diffraction peak by the (110) plane in the X-ray diffraction measurement using Cu-Kα rays of the reference light-absorbing layer made of polycrystals of the same perovskite compound grain as the compound film) The method of claim 4,
The molecule of the organic monomolecular film is a perovskite solar cell having a -NH ₃ ⁺ head group and a C6 or higher alkyl chain bonded to a metal-halogen inorganic skeleton of the perovskite compound grain. The method of claim 5,
The alkyl chain is a C8 to C12 normal alkyl perovskite solar cell. An organic metal halide of a perovskite structure is a perovskite compound grain and a grain boundary, and includes an alkylammonium metal halide surrounding the grain, X-ray using Cu Kα ray In the diffraction pattern, a perovskite compound film containing only a crystal structure by a three-dimensional perovskite compound grain is included as a light absorbing layer, and the perovskite compound film satisfies the following relation 1 .
(Relationship 1)
I (110) / I ₀ (110) ≥ 2
(In the relational expression 1, I (110) is the intensity of the diffraction peak by the (110) plane in X-ray diffraction measurement using Cu-Kα rays of the perovskite compound film, and I ₀ (110) is the perovskite The intensity of the diffraction peak by the (110) plane in the X-ray diffraction measurement using Cu-Kα rays of the reference light-absorbing layer made of polycrystals of the same perovskite compound grain as the compound film) The method of claim 7,
The alkyl of the alkyl ammonium metal halide is C6 or more normal alkyl perovskite solar cell. The method of claim 8,
The alkyl of the alkyl ammonium metal halide is a C8 to C12 normal alkyl perovskite solar cell. The method according to any one of claims 1 to 9,
The perovskite compound membrane has an average grain size of 200 to 700 nm based on the surface of the membrane, and a perovskite solar cell having a porosity of 0.05 to less than the pore area per unit area based on the perovskite compound membrane surface. The method according to any one of claims 1 to 9,
The solar cell includes a first electrode; An electron carrier positioned on the first electrode; And a light absorbing layer including the perovskite compound film covering the electron transporter. A hole transporter located on the light absorbing layer; And a second electrode. The method according to any one of claims 1 to 9,
The perovskite compound film is a perovskite solar cell in which diffraction peaks are not detected in a range of diffraction angles 2θ 3.5 to 12.0 ° in X-ray diffraction measurement using Cu-Kα rays. The method according to any one of claims 1 to 9,
The perovskite compound film is a perovskite solar cell having an FWHM (Full Width at Half Maximum) of a diffraction peak by the (110) plane of 0.16 ° or less in X-ray diffraction measurement using Cu-Kα rays. delete The method according to any one of claims 1 to 9,
The perovskite compound membrane is a grazing incidence wide angle X-ray scattering (GIWAXS; Grazing Incidence) using a monochromatic X-ray, which is a scattering intensity distribution in which the scattering vector component q _z is the y-axis and the scattering vector component q _xy is the x-axis. Wide Angle X-ray Scattering) A perovskite solar cell that has a non-uniform scattering intensity on the (110) plane and has the largest scattering intensity at q _xy = 0. The method according to any one of claims 7 to 9,
The perovskite compound membrane is a perovskite solar cell containing 0.5 to 5 mol% of the alkylammonium metal halide. The method of claim 4,
The perovskite compound film is a perovskite solar cell containing 0.5 to 5 mol% of an organic single molecule. The method according to any one of claims 1 to 3,
The perovskite compound membrane is a perovskite solar cell containing 0.5 to 5 mol% of normal alkylammonium ions. A method for manufacturing a perovskite solar cell according to any one of claims 1 to 9,
a) forming an electron carrier on the first electrode;
b1) adding C6 or higher normal alkylammonium halide, organic halide and divalent metal halide to the first solvent and heating to obtain a perovskite powder modified with alkylammonium ion; And dissolving the perovskite powder modified with an alkylammonium ion in a second solvent to prepare an organic capping agent-perovskite solution;
b2) forming a light absorbing layer by applying an organic capping agent-perovskite solution on the electron carrier; And
c) sequentially forming a hole transporter and a second electrode on the light absorbing layer;
Method of manufacturing a perovskite solar cell comprising a. delete The method of claim 19,
The method of manufacturing a perovskite solar cell wherein the C6 or higher normal alkyl is C8 to C12 normal alkyl. The method of claim 19,
A method of manufacturing a perovskite solar cell having a mole number of divalent metal halides input to the first solvent in step b1): C6 or higher of a normal alkylammonium halide of 100: 0.5 to 5.

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