KR101578875B1 - Solar cell comprising self-organized dielectric substance and method of manufacturing the same - Google Patents

Abstract

The present invention provides a solar cell including a first electrode, a hole-blocking layer formed on the first electrode, a light adsorption layer formed on the hole-blocking layer, and a second electrode formed on the light adsorption layer wherein the hole-blocking layer includes a self-organized dielectric. Therefore, the solar cell can be processed at room temperature by using the hole-blocking layer including the self-organized dielectric, and has high efficiency at the same time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell including a self-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell and a manufacturing method thereof, and more particularly, to a solar cell including a hole blocking layer including a self-organized dielectric material, .

Generally, a solar cell is a device that converts solar light energy into electric energy. A solar cell is a tool for producing electricity using sunlight, which is an infinite energy source, and is a silicon solar cell already widely used in our life. Recently, a dye-sensitized solar cell has been studied as a next generation solar cell. The dye-sensitized solar cell is a photoelectrochemical solar cell that has the potential to replace conventional silicon solar cells because it has higher efficiency and lower manufacturing cost than conventional silicon solar cells.

Dye-sensitized solar cells have been reported by Michael Gratzel of the Swiss National Lozanne Institute for Advanced Technology (EPFL) in 1991 (see US Pat. No. 5,350,644 "Photovoltaic cells"). In terms of structure, one of the two electrodes of the dye-sensitized solar cell is a photoelectrode including a conductive transparent substrate having a semiconductor layer on which a photosensitive dye is adsorbed, and the space between the two electrodes is filled with an electrolyte.

The operation principle of the dye-sensitized solar cell is as follows. The solar energy is absorbed by the photosensitive dye adsorbed on the semiconductor layer of the electrode to generate photoelectrons. The photoelectrons are conducted through the semiconductor layer and transferred to the transparent conductive substrate, The oxidized dyes that lose electrons are reduced by oxidation / reduction pairs contained in the electrolyte. On the other hand, the electrons reaching the counter electrode, which is the opposite electrode through the external electric wire, complete the operation of the solar cell by reducing the redox pair of the oxidized electrolyte again.

In general, a dye-sensitized solar cell is formed by coating a TiO ₂ thin film on a glass substrate coated with transparent electrically conductive ITO or FTO, activating TiO ₂ through a calcination process at 500 ° C., and then adsorbing N 3 or various kinds of dyes After the dye was adsorbed to the TiO ₂ thin film micropores through a long time of adsorption process, I / I 3 was dissolved in an organic solvent and used as a liquid electrolyte, and the upper part of the electrolyte was bonded to a final platinum coated glass substrate to complete the solar cell Method is a generally known method so far, and a dye-sensitized solar cell having an efficiency of up to 11% can be produced in a laboratory unit by using such a method.

However, in order to realize the production of ultra low cost solar cell which is the most advantage of the dye-sensitized solar cell, it is essential to apply a roll-to-roll printing process using a plastic substrate coated with a transparent electrode. In fact, many studies have been conducted worldwide for this purpose. Therefore, a dye-sensitized solar cell can be produced on a plastic substrate such as PET, which is weak in heat, in a roll-to-roll printing process, so that an ultra-low-cost solar cell can be realized. For this purpose, the TiO ₂ thin film heat treatment process, which requires a high-temperature calcination process, and the long-term adsorption process in which the dye is adsorbed on the TiO ₂ thin film, A technique capable of producing a TiO ₂ layer is indispensable. For this purpose, ZnO nanocrystals similar to TiO _{2 have been used} instead of TiO ₂ , but TiO ₂ thin films can be substituted, and techniques using polymers capable of room temperature processing have not been reported yet.

One of the objects of the present invention is to provide a solar cell which uses perovskite-based dyes and which includes a self-organized dielectric material to process at room temperature and at the same time has high efficiency .

According to an aspect of the present invention,

A first electrode; A hole blocking layer formed on the first electrode; A light absorption layer formed on the hole blocking layer; And a second electrode formed on the light absorption layer, wherein the hole blocking layer includes a self-organized dielectric material.

The surface of the hole blocking layer in the direction opposite to the first electrode is polarized at? - and the surface in the direction opposite to the direction opposite to the first electrode is polarized at? +.

The hole blocking layer may have a thickness of 4 to 12 nm.

The hole blocking layer may include a compound represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1

x + y + z? 0,

X < / = 5000,

0 < / = y < / = 5000,

0 < / = z < / = 5,000.

The hole blocking layer may include at least one selected from the group consisting of ethoxylated polyethylenimine, polyethyleneimine, and polyallylamine.

The hole blocking layer may comprise ethoxylated polyethyleneimine.

The light absorption layer can be induced in a direction in which a dipole moment is opposite to the hole blocking layer.

The first electrode may include at least one selected from the group consisting of fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide, have.

The light absorbing layer may include a compound having a perovskite structure.

The perovskite structure compound may be CH ₃ NH ₃ PbI _{3 - x} Cl _x (real number 0 ≤ _x ≤ ₃ ), CH ₃ NH ₃ PbI _{3 - x} Cl _x (0 ≤ _x ≤ ₃ real number _{), CH 3 NH 3 PbI 3} - x Br x (0≤x≤3 _{mistakes), CH 3 NH 3 PbCl 3} -x Br x (0≤x≤3 a real number), and CH ₃ NH ₃ PbI _{3 - x} And F _x (real number of 0? _X ? 3).

The light absorption layer may include an oxide of at least one metal selected from aluminum, titanium, tin, zinc, tungsten, zirconium, gallium, indium, yttrium, niobium, tantalum and vanadium.

The solar cell may further include a hole transporting layer between the light absorbing layer and the second electrode.

The hole transport layer may include at least one selected from Spiro-OMeTAD, P3HT, P3AT, P3OT, PEDOT: PSS, PTAA, and conductive polymer.

The solar cell may further include a substrate on the first electrode in a direction opposite to the direction in which the solar cell opposes the hole blocking layer.

The substrate may comprise a conductive transparent substrate or a plastic substrate.

The second electrode may include at least one selected from Ag, Au, Pt, Ni, Cu, In, Ru, Pd, Rh, Ir, Os, and a conductive polymer.

According to another aspect of the present invention,

Forming a first electrode (step a); Forming a hole blocking layer including a dielectric self-organized on the first electrode (step b); Forming a light absorption layer on the hole blocking layer (step c); And forming a second electrode on the light absorption layer (step d).

Step b may be a step of coating a solution of a compound represented by the following structural formula 1 on the first electrode and drying at 0 to 30 캜 to form a hole blocking layer containing a self-organized dielectric.

[Structural formula 1]

In the above formula 1

x + y + z? 0,

X < / = 5000,

0 < / = y < / = 5000,

0 < / = z < / = 5,000.

The coating of step b may be carried out in any one of the following methods: doctor blade, screen printing, spin coating, and spray coating.

Unlike the prior art, the solar cell of the present invention has a self-organizing dielectric layer, so that the hole blocking layer efficiently transfers electrons and blocks holes.

In addition, since the process can be performed at room temperature and at the same time has a high efficiency, it can be applied to flexible electronic devices, wearable devices, and the like.

1 is a schematic view of a solar cell of the present invention.
2 is a flowchart of a method for manufacturing a solar cell according to the present invention.
3 is an image of ethoxylated polyethyleneimine (PEIE) and a light absorbing layer formed on an FTO substrate.
4 is a graph showing a change in thickness and work function according to PEIE concentration.
5 is a photocurrent-light voltage graph according to the concentration of PEIE of the solar cell according to Examples 1 to 8.
6 is a graph illustrating the diode characteristics of the solar cell according to Examples 4, 5, 6, and 8.
7 shows the incident photon-to-current efficiency (IPCE) and J _SC values of the solar cells according to Examples 3, 4, 6 and 8.
FIG. 8 is a graph comparing the characteristics of a solar cell including a PEIE layer and a solar cell including d-TiO ₂ .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description does not limit the present invention to specific embodiments. In the following description of the present invention, detailed description of related arts will be omitted if it is determined that the gist of the present invention may be blurred .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises ", or" having ", and the like, specify that the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or combinations thereof.

Hereinafter, the solar cell of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

1 is a schematic view of a solar cell of the present invention.

1, the solar cell of the present invention includes a first electrode, a hole blocking layer formed on the first electrode, a light absorbing layer formed on the hole blocking layer, and a second electrode formed on the light absorbing layer , And the hole blocking layer may include a self-organized dielectric.

A dielectric refers to an insulator or polarization that does not conduct electricity.

The surface of the hole blocking layer in the direction opposite to the first electrode is polarized at? - and the surface in the direction opposite to the direction opposite to the first electrode is polarized at? +.

The polarized moment of the light absorbing layer can be induced in the direction opposite to the hole blocking layer by the polarized hole blocking layer.

The thickness of the hole blocking layer may be 4 to 12 nm, preferably 6 to 11 nm, more preferably 8 to 10 nm.

The hole blocking layer may include a compound represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1

x + y + z? 0,

X < / = 5000,

0 < / = y < / = 5000,

0 < / = z < / = 5,000.

The hole blocking layer may include ethoxylated polyethyleneimine, polyethylenimine, and polyallylamine. The hole blocking layer may include an ethoxylated polyethyleneimine.

The first electrode may include fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide and zinc oxide, Fluorine tin oxide.

The light absorbing layer may include, but is not limited to, a compound having a perovskite structure. A light absorbing layer material such as a conventional ruthenium metal complex can be used.

The perovskite-structured compound may be CH ₃ NH ₃ PbI _{3 - x} Cl _x (real number 0 ≤ _x ≤ ₃ ), H ₃ NH ₃ PbI _3-x Cl _x (real number 0 ≤ _x ≤ ₃ ), CH ₃ NH ₃ PbI _{3 - x} Br _x (real number 0 ≤ _x ≤ ₃ ), CH ₃ NH ₃ PbCl _{3 - x} Br _x (real number 0 ≤ _x ≤ ₃ ), and CH ₃ NH ₃ PbI _{3 - x} F _x 0≤x≤3 of the real number) such as the one available preferably from _{CH 3 NH 3 PbI 3-x} Cl x (0≤x≤3 a real number).

The light absorption layer may include oxides of metals such as aluminum, titanium, tin, zinc, tungsten, zirconium, gallium, indium, yttrium, niobium, tantalum, and vanadium, but may preferably include aluminum oxide.

The light absorption layer may be formed by first forming a metal oxide layer having a nanostructure, and then coating a perovskite structure compound on the metal oxide layer.

A hole transporting layer may further be included on the light absorption layer.

The hole transport layer may include Spiro-OMeTAD, P3HT, P3AT, P3OT, PEDOT: PSS, PTAA, and conductive polymer, but may preferably include Spiro-OMeTAD.

The solar cell may further include a substrate on the first electrode in a direction opposite to the direction opposite to the hole blocking layer, and the substrate may include a conductive transparent substrate or a plastic substrate.

Since the solar cell includes a hole blocking layer including a self-organized dielectric material, the solar cell can be manufactured at room temperature and may include a plastic substrate.

The second electrode may be Ag, Au, Pt, Ni, Cu, In, Ru, Pd, Rh, Ir, Os, C and a conductive polymer.

2 is a flowchart of a method for manufacturing a solar cell according to the present invention.

Referring to FIG. 2, the method of manufacturing a solar cell of the present invention first forms a first electrode (step a).

The first electrode may be formed on a substrate, but is not limited thereto. Only the first electrode without the description can be formed.

The first electrode may include fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide and zinc oxide, Fluorine tin oxide.

The first electrode may be cleaned and / or etched prior to the next step (step b), but is not limited thereto.

Next, a hole blocking layer including a dielectric self-organized on the first electrode is formed (step b).

Step b may be a step of coating a solution of the compound represented by the following structural formula 1 on the first electrode and drying at 0 to 30 캜 to form a hole blocking layer containing a self-organized dielectric.

[Structural formula 1]

In the above formula 1

x + y + z? 0,

X < / = 5000,

0 < / = y < / = 5000,

0 < / = z < / = 5,000.

In the drying process of step (b), the surface of the hole blocking layer in the direction opposite to the first electrode is polarized at? - and the surface in the direction opposite to the direction opposite to the first electrode is polarized at? +.

The polarized moment of the light absorbing layer can be induced in the direction opposite to the hole blocking layer by the polarized hole blocking layer.

The solution of the compound represented by the structural formula 1 may have a concentration of 0.4 to 1.2% by weight, preferably 0.6 to 1.1% by weight, more preferably 0.7 to 1.0% by weight.

The hole blocking layer may include ethoxylated polyethyleneimine, polyethylenimine, and polyallylamine. The hole blocking layer may include an ethoxylated polyethyleneimine.

The coating of step b may be performed by a method such as doctor blade, screen printing, spin coating, spray coating and the like, but may preferably be performed by a spin coating method. However, the present invention is not limited thereto.

Next, a light absorption layer is formed on the hole blocking layer (step c).

The light absorbing layer may include, but not limited to, a compound of a metal oxide and a perovskite structure. A light absorbing layer material such as a conventional ruthenium metal complex can be used.

Step c may also comprise the following steps.

First, a solution of an oxide of a metal such as aluminum, titanium, tin, zinc, tungsten, zirconium, gallium, indium, yttrium, niobium, tantalum and vanadium is coated on the hole blocking layer (step c-1).

The oxide solution of the coated metal is heat-treated (step c-2).

Step c-2 can be carried out at 100-200 占 폚, preferably 130-170 占 폚. Step c-2 can also be carried out for 30 minutes to 1 hour 30 minutes, preferably 45 minutes to 1 hour 15 minutes. However, the execution time may vary depending on the temperature.

Next, a compound precursor solution of perovskite structure is coated on the oxide of the metal (step c-3).

Finally, the coated solution of the compound of perovskite structure is heat-treated (step c-4).

Step c-4 can be carried out at 50 to 150 ° C, preferably at 80 to 120 ° C. In addition, step c-4 can be carried out for 1 hour to 3 hours, preferably for 1 hour and 30 minutes to 2 hours. However, the execution time may vary depending on the temperature.

Step c Next, a step of forming a hole transport layer on the light absorption layer may be further included (step c ').

The hole transport layer may be formed by coating a solution of Spiro-OMeTAD, P3HT, P3AT, P3OT, PEDOT: PSS, PTAA, conductive polymer or the like.

Finally, a second electrode is formed (step d).

The second electrode may be formed by depositing Ag, Au, Pt, Ni, Cu, In, Ru, Pd, Rh, Ir, Os, or the like. The second electrode may be formed using a conductive polymer or the like.

[Example]

Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

Manufacturing example  One: Ethoxylation  Preparation of polyethyleneimine dissolution liquid

0.005 g of ethoxylated polyethyleneimine ethoxylated was dissolved in 9.995 g of ethanol to prepare a 0.05 wt% ethoxylated polyethyleneimine solution.

Manufacturing example  2

A 0.1 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Preparation Example 1 except that 9.99 g instead of 9.995 g of ethanol and 0.01 g of 0.005 g of ethoxylated polyethyleneimine were used.

Manufacturing example  3

A 0.4 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Production Example 1, except that 9.96 g instead of 9.995 g of ethanol and 0.04 g instead of 0.005 g of ethoxylated polyethyleneimine were used.

Manufacturing example  4

A 0.6 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Preparation Example 1, except that 9.94 g of ethoxylated polyethyleneimine was used instead of 0.005 g of ethoxylated polyethyleneimine in place of 9.995 g of ethanol.

Manufacturing example  5

A 0.7 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Production Example 1, except that 9.93 g of ethoxylated polyethyleneimine was used instead of 0.0099 g of ethoxylated polyethyleneimine in place of 9.995 g of ethanol.

Manufacturing example  6

A 0.8 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Preparation Example 1 except that 9.92 g of ethoxylated polyethyleneimine was used instead of 0.005 g of ethoxylated polyethyleneimine in place of 9.995 g of ethanol.

Manufacturing example  7

A 0.9 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Preparation Example 1, except that 9.91 g of ethoxylated polyethyleneimine was used instead of 0.0099 g of ethoxylated polyethyleneimine in place of 9.995 g of ethanol.

Manufacturing example  8

A 1.0 wt% ethoxylated polyethyleneimine solution was prepared in the same manner as in Production Example 1 except that 9.9 g of ethoxylated polyethyleneimine was used instead of 0.005 g of ethoxylated polyethyleneimine in place of 9.995 g of ethanol.

Example  1: Manufacture of solar cell

FTO substrate was etched with Zn 2M HCl solution and washed with detergent, acetone, ethanol, IPA. Thereafter, a 0.05 wt% ethoxylated polyethyleneimine solution of Production Example 1 was spin-coated at 5000 rpm for 60 seconds and then dried at room temperature for 15 minutes to form a hole blocking layer. The solution prepared by dispersing aluminum oxide (Al ₂ O ₃ ) on the coated ethoxylated polyethyleneimine in IPA was spin-coated at 2000 rpm for 60 seconds and then heat-treated at 150 ° C for 1 hour. Subsequently, Methylammonium Iodide and PbCl ₂ were mixed in DMF at a molar ratio of 3: 1 to prepare a 40 wt% CH ₃ NH ₃ PbI _{3 - x} Cl _x (0 ≦ _x ≦ ₃ real) precursor solution. The precursor solution of CH ₃ NH ₃ PbI _{3 - x} Clx (0 ≦ _x ≦ ₃ ) precursor solution was spin-coated on the aluminum oxide at 2000 rpm for 60 seconds and then crystallized at 100 ° C. for 2 hours to obtain a perovskite structure Was formed. A hole transport layer by spin coating for 60 seconds with a spiro-MeOTAD 2000rpm on the _{CH 3 NH 3 PbI 3-x} Cl x (0≤x≤3 a real number) of the crystallized form. Silver (Ag) was deposited on the spiro-MeOTAD to form a second electrode to produce a solar cell.

Example  2

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 2 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  3

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 3 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  4

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 4 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  5

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 5 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  6

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 6 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  7

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 7 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Example  8

A solar cell was prepared in the same manner as in Example 1, except that the ethoxylated polyethyleneimine solution of Preparation Example 8 was used instead of the ethoxylated polyethyleneimine solution of Preparation Example 1.

Comparative Example  One

Except that a solution prepared by dissolving titanium (IV) isopropoxide in ethanol at a molar concentration of 0.24 mM instead of the ethoxylated polyethyleneimine dissolution solution of Preparation Example 1 was used, .

[Test Example]

Test Example  1: Coated Ethoxylation  Polyethyleneimine ( PEIE ) And The light absorbing layer  Confirm

3 (a) is an energy-dispersive X-ray spectroscopy (EDS) image of polyethylenimine ethoxylated (PEIE) coated on an FTO substrate and FIG. 3 (b) Aluminum oxide (Al ₂ O ₃ ) and d-TiO ₂ And SEM (scanning electron microscopy) image of the aluminum oxide (Al ₂ O ₃₎ formed on, (c) of Figure 3 PEIE / aluminum oxide (Al ₂ O ₃₎ formed on the Fe lobe of the Sky bit structure CH ₃ NH _{3 PbI 3 - x Cl x (} 0≤x≤3 a real number) and d-TiO ₂ / aluminum oxide (Al ₂ O ₃₎ formed on a perovskite structure _{CH 3 NH 3 PbI 3 - x} Cl x (0 ≪ / = x < / = 3).

Referring to FIG. 3 (a), the blue dot indicates the nitrogen atom of the PEIE, so that it was confirmed that the FTO substrate was well coated with PEIE.

Referring to FIG. 3 (b), aluminum oxide (Al ₂ O ₃ ) and d-TiO ₂ (Al ₂ O ₃ ) formed on the substrate was almost the same SEM image. Therefore, it was found that the nano-structured aluminum oxide (Al ₂ O ₃ ) was well formed on the PEIE.

Referring to FIG. 3 (c), CH ₃ NH ₃ PbI _{3 - x} Cl _x (a real number of 0 _{? X? 3} ) of a perovskite structure formed on PEIE / aluminum oxide (Al ₂ O ₃ ) The SEM image was almost the same when the perovskite structure CH ₃ NH ₃ PbI _{3 - x} Cl _x (real number of 0 _{? X? 3} ) formed on TiO ₂ / aluminum oxide (Al ₂ O ₃ ) . Therefore, it was found that CH ₃ NH ₃ PbI _{3 - x} Cl _x (real number of 0 _{? X? 3} ) having a perovskite structure was well formed on PEIE / aluminum oxide (Al ₂ O ₃ ).

Test Example  2: PEIE  The thickness according to concentration Work function  change

4 (a) is a graph showing the thickness and work function of PEIE measured by ellipsometry after spin-coating and drying the PEIE solution according to Production Examples 1 to 8 on the FTO substrate, and Fig. 4 (B) is a graph showing a work function measured by UPS (ultraviolet photoelectron spectroscopy) after spin-coating and drying the PEIE solution according to Production Examples 1, 2, 3 and Production Example 8 on an FTO substrate.

Referring to FIGS. 4 (a) and 4 (b), it can be seen that as the concentration of the PEIE solution increases, the thickness of the PEIE increases proportionally. In addition, the work function of the PEIE decreased linearly to 3.93 eV, the vacuum level, while the thickness of the PEIE increased to 4.7 nm, and was almost constant at 3.93 eV above that. Also, there was little change in binding energy until it increased from 4.7 nm thick to 10.8 nm.

Therefore, it was found that the PEIE layer of 4.7 nm or thicker was self-organized and formed a dielectric interlayer.

Test Example  3: PEIE  Depending on concentration Photovoltaic  Parameter change

The photovoltaic parameters of photovoltaic cells according to Examples 1 to 8 under solar illumination of 0.09 cm < ² > cell size, AM 1.5G, parameter are shown in Table 1. Based on this, graphs of photocurrent-light voltage according to the concentration of PEIE of the solar cells according to Examples 1 to 8 are shown in FIG.

Referring to Table 1 and FIG. 5, when the thicknesses of the PEIE are 0.46 nm and 1.2 nm (case 1), short circuit current density (J _SC ), fill factor (FF) (J _SC : 14.9-15.5 mA / cm ² , FF: 40.7-41.5%, V _OC : 0.52-0.81 V), respectively. Therefore, the PEIE layer forms a weak dielectric layer, and the dipole moment is weakly induced in the light absorbing layer having the perovskite structure.

When the thickness of the PEIE was 4.7 nm and 7.0 nm (case 2), J _SC increased to 19.0-20.4 mA / cm ² with V _OC, and FF increased to 52.4-49.9%. However, even though the FF value was still low, the electron extraction ability was improved, but the electron loss mechanism was operated and the J _SC value was lowered.

When the thickness of the PEIE was 8.1 nm and 9.1 nm (case 3), FF value was 64.7%, J _SC was 21.1 mA / cm ² , V _OC The value increased to 1.10 V and the power conversion efficiency (η) also increased to 15.0%. Therefore, it was found that when the thickness was 8.1 nm and 9.1 nm, the insulation characteristics were improved while maintaining the electron extraction capability.

When the thickness of the PEIE is 9.9 nm and 10.8 nm (case 4), J _SC As the value decreased from 21.1 mA / cm ² to 16.3 mA / cm ² , the photovoltaic performance decreased due to the interference of electron tunneling from the light absorption layer to the FTO substrate. FF value was expected to remain at 64.7%, but it actually decreased to 53.4%. It is considered that this is due to the unexpected recombination of the holes in the light absorbing layer and the photoinduced electron.

PEIE
(wt%) thickness
(nm) V _OC
[V] J _SC
[mA / cm ² ] FF
[%] η
[%] 0.05 0.46 0.52 14.9 41.5 3.2 0.1 1.2 0.81 15.5 40.7 5.1 0.4 4.7 1.01 19.0 52.4 10.0 0.6 7.0 1.06 20.4 49.9 10.8 0.7 8.1 1.09 20.7 61.9 13.9 0.8 9.1 1.10 21.1 64.7 15.0 0.9 9.9 1.09 16.3 53.4 9.5 1.0 10.8 1.10 15.3 49.0 8.3

Test Example  4: PEIE  Layer Fill Factor  Diode characteristics when the value is large

Diode characteristics of the solar cells according to Examples 4, 5, 6 and 8 were measured and shown in Fig.

Referring to FIG. 6, when the FF value is high, the diode characteristics of the solar cell according to the small change in the thickness of the PEIE are slightly increased as the thickness is increased from 7.0 nm to 8.1 nm. However, . This indicates that the PEIE dielectric insulating layer having a thickness of 9.1 nm or more sufficiently blocks the recombination reaction. However, the decrease in J _SC value at 9.9 nm and 10.8 nm indicates that the insulating property interferes with electron tunneling from the light absorption layer to the FTO substrate. Therefore, the thickness of the PEIE layer is about 9.1 nm .

Test Example  5: PEIE  IPCE according to layer thickness ( incident photon - to - current  efficiency measurement

The IPCE of the solar cell according to Examples 3, 4, 6 and 8 was measured and shown in FIG. 7 (a), and the J _SC value is shown in FIG. 7 (b).

Referring to Figs. 7 (a) and 7 (b), the theoretical J _SC value was calculated by the following equation (1).

[Formula 1]

J _SC = e? {? (?) XIPCE (?)} D?

e is the charge quantity, and IPCE (λ) and Φ (λ) are the photon flux incident on the device at the IPCE value and the wavelength range λ _min - λ _max .

The J _SC value calculated by Equation (1) is in good agreement with the actually measured value, so that it can be seen that all of the values measured in the test example are reliable values.

Test Example  6: PEIE  Lt; RTI ID = 0.0 > d- TiO ₂ ≪ / RTI >

A solar cell including a PEIE layer and a d-TiO ₂ In order to compare the characteristics of the solar cell including the layer (thickness: 50 nm), a solar cell according to Example 6 and a solar cell according to Comparative Example 1 under a cell size of 0.09 cm ² , AM 1.5G solar illumination The characteristics of the solar cell are compared in FIG. 8 and Table 2 below.

Referring to FIG. 8 and Table 2, the power conversion efficiency? Of the solar cell according to Comparative Example 1 was 12.0%, which was 25.0% lower than that of the solar cell according to Example 6 (? = 15.0%). The main reason is that the difference in V _OC values (V _OC of Comparative Example 1 = 0.97 V, V _OC of Example 6 = 1.10 V).

Therefore, the self-organized PEIE layer has a dielectric property that induces a strong dipole moment in the light absorption layer having a perovskite structure, and also has an effect of reducing the work function of the FTO transparent electrode. This effect can reduce the interfacial resistance to achieve 1.1 V, which is close to 1.4 V, the theoretical V _OC . It also exhibits very small series resistance (R _series ) and large shunt resistance (R _shunt ). That is, when the solar cell of the present invention is a conventional d-TiO ₂ Layer of the solar cell.

division V _OC
[V] J _SC
[mA / cm ² ] FF
[%] η
[%] R _shunt
[Ω] R _series
[Ω] PEIE 1.10 21.1 64.7 15.0 226 60 d-TiO ₂ 0.97 20.6 60.1 12.0 167 84

Claims (20)

A first electrode;
A hole blocking layer formed on the first electrode;
A light absorption layer formed on the hole blocking layer; And
And a second electrode formed on the light absorption layer,
Wherein the hole blocking layer comprises a self-organized dielectric,
The surface of the hole blocking layer in the direction opposite to the first electrode is polarized at? - and the surface in the direction opposite to the direction opposite to the first electrode is polarized at? +. delete The method according to claim 1,
Wherein the hole blocking layer has a thickness of 4 to 12 nm. The method according to claim 1,
Wherein the hole blocking layer comprises a compound represented by the following structural formula (1).
[Structural formula 1]

In the above formula 1
x + y + z? 0,
X < / = 5000,
0 < / = y < / = 5000,
0 < / = z < / = 5,000. The method according to claim 1,
Wherein the hole blocking layer comprises at least one selected from the group consisting of ethoxylated polyethylenimine, polyethyleneimine, and polyallylamine. 6. The method of claim 5,
Wherein the hole blocking layer comprises an ethoxylated polyethyleneimine. The method according to claim 1,
Wherein the light absorption layer has a dipole moment induced in a direction opposite to the hole blocking layer. The method according to claim 1,
Wherein the first electrode comprises at least one selected from the group consisting of fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide and zinc oxide . The method according to claim 1,
Wherein the light absorbing layer comprises a compound having a perovskite structure. 10. The method of claim 9,
The perovskite structure compound may be CH ₃ NH ₃ PbI _{3 - x} Cl _x (real number 0 ≤ _x ≤ ₃ ), H ₃ NH ₃ PbI _{3 - x} Cl _x (0 ≤ _x ≤ ₃ real number _{), CH 3 NH 3 PbI 3} - x Br x (0≤x≤3 _{mistakes), CH 3 NH 3 PbCl 3} -x Br x (0≤x≤3 a real number), and CH ₃ NH ₃ PbI _{3 - x} And F _x (real number of 0? _X ? 3). The method according to claim 1,
Wherein the light absorption layer comprises an oxide of at least one metal selected from aluminum, titanium, tin, zinc, tungsten, zirconium, gallium, indium, yttrium, niobium, tantalum, and vanadium. The method according to claim 1,
Wherein the solar cell further comprises a hole transporting layer between the light absorbing layer and the second electrode. The method of claim 12, wherein
Wherein the hole transporting layer comprises at least one selected from the group consisting of Spiro-OMeTAD, P3HT, P3AT, P3OT, PEDOT: PSS, PTAA and conductive polymer. The method according to claim 1,
Wherein the solar cell further comprises a substrate on the first electrode in a direction opposite to the direction in which the solar cell faces the hole blocking layer. 15. The method of claim 14,
Wherein the substrate comprises a conductive transparent substrate or a plastic substrate. The method according to claim 1,
Wherein the second electrode comprises at least one selected from Ag, Au, Pt, Ni, Cu, In, Ru, Pd, Rh, Ir, Os, C and a conductive polymer. Forming a first electrode (step a);
Forming a hole blocking layer including a dielectric self-organized on the first electrode (step b);
Forming a light absorption layer on the hole blocking layer (step c); And
And forming a second electrode on the light absorbing layer (step d)
Wherein the hole blocking layer is polarized at a surface of the hole in the direction facing the first electrode by? - and the surface in the direction opposite to the direction facing the first electrode is polarized at? +. 18. The method of claim 17,
Step b is a step of coating a solution of the compound represented by the following structural formula 1 on the first electrode and drying at 0 to 30 DEG C to form a hole blocking layer containing a self-organized dielectric Gt;
[Structural formula 1]

In the above formula 1
x + y + z? 0,
X < / = 5000,
0 < / = y < / = 5000,
0 < / = z < / = 5,000. 18. The method of claim 17,
Wherein the coating of step (b) is carried out by any one method selected from the group consisting of doctor blade, screen printing, spin coating and spray coating. 20. The method of claim 19,
Wherein the coating of step (b) is carried out by a method of spin coating.

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