KR101559246B1 - Solar cell using p-type oxide semiconductor comprising gallium, and method of manufacturing the same - Google Patents

Abstract

The present invention discloses a solar cell using a p-type oxide semiconductor containing gallium (Ga) and a manufacturing method thereof. According to the present invention, the solar cell includes a positive electrode, a hole transport layer, a photoactive layer, an electron transport layer, and a negative electrode. The hole transport layer is the p-type oxide semiconductor containing gallium.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell using a p-type oxide semiconductor including gallium and a method of manufacturing the same,

The present invention relates to a solar cell using a p-type oxide semiconductor containing gallium and a method for manufacturing the same.

Solar cell is a device that directly converts light energy into electric energy. In the early stage of commercialization, research on crystalline silicon solar cell with high conversion efficiency has been actively performed. However, there is a limitation in high production cost, weight and flexibility, Research on batteries is actively under way.

Organic solar cells can be manufactured using flexible organic materials because they can be manufactured with a large area through solution process and can be expected to have high productivity. Since the thickness of the entire device is only a few hundred nanometers and can be flexibly manufactured, It is expected that there will be explosive demand of organic solar cells in the market where inorganic solar cells can not be used recently.

Organic solar cells can be simply represented by a metal-organic semiconductor (photoactive layer) -metal structure. In general, ITO (Indium Tin Oxide), which is a transparent electrode having a high work function, is used as an anode and Al or Ag Is used as a negative electrode material. The photoactive layer has a two-layer structure (D / A bilayer structure) or bulk-heterojunction (D + A) blend of an electron donor and an electron acceptor having a thickness of about 100 nm (D / A) / (D + A) / (D + A)) structure in which the bulk bulk-heterojunction structure of the latter is interposed between donor- A) is also used.

However, one of the major problems of limiting the photocurrent and efficiency of organic solar cells is the low charge mobility of organic materials in the bulk state. Organic semiconductors have many defects in terms of molecular structure and crystallinity, and their charge mobility is very low compared to those of inorganic materials. For example, in the case of semiconductor polymer / C60, it is believed that the low mobility of such charges is due to the low photocurrent, despite the very high electron-hole isolation efficiency. In particular, in organic semiconductors, the mobility of electrons is generally lower than the mobility of holes, and such low charge mobility has always been a problem in organic semiconductor devices such as organic light emitting devices.

Efforts have been made to improve the mobility of charges. In order to improve the mobility of charges by well controlling the surface shape in the fabrication of an organic thin film solar cell device, or to facilitate the charge injection at each electrode, And a method of lowering the energy barrier between the electrode and the organic material interface by adding a buffer layer between the electrode and the organic material interface.

Furthermore, a buffer layer is added between the organic thin films to improve the charge mobility and change the direction of charge transfer, which is referred to as an inverted organic solar cell.

Conventional techniques for an inverted organic solar cell can be understood with reference to Patent Document 1 below. As a result, the contents of Patent Document 1 are cited in the entire contents of this specification as prior art.

Patent Literature 1 discloses a solar cell module in which a Cs ₂ CO ₃ layer and a MoO ₃ layer are inserted between both electrodes and an active layer to change the polarity of the electrode, thereby increasing the lifetime and stability of the solar cell For an inverted organic solar cell.

In order to fabricate a high performance organic solar cell, hole transport is a very important part. As a typical hole transport layer, PEDOT: PSS (poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate)) layer is used but the hole injection and transport and stability of the solar cell are limited.

Further, in the case of using PEDOT: PSS as the hole transporting layer, annealing time is required, so that the process time is long.

On the other hand, studies are underway to replace the hole transport layer with oxide semiconductors.

This is because oxide semiconductors are highly mobility and transparent and can be easily realized as a transparent display and have been evaluated as an alternative technique capable of overcoming the limitations of the prior art (see Non-Patent Document 1 below).

The oxide semiconductor is a direct semiconductor which has a high mobility (1 to 100 [cm ² / Vs]) and a high band gap, and oxidation phenomenon does not occur unlike a silicon-based device. .

In addition, since it has an amorphous or polycrystalline structure at room temperature, there is no need for a heat treatment process for forming a grain separately, and excellent characteristics are exhibited when a solar cell is applied.

However, oxide semiconductors are reported to be mainly n-type due to oxygen vacancies and zinc interstitials, and p-type doping is difficult to achieve.

Since most of the oxide semiconductors known to date have n-type characteristics, when transparent oxide semiconductors having p-type characteristics are realized, there are many advantages in utilizing solar cells as a hole transport layer. Therefore, doping condition control or new material development And it is necessary to investigate the p-type transparent oxide semiconductor material.

KR 10-1110810 B1 (2012.01.20.)

 A. P. Ramirez, " Oixde Electonics Emerge ", Science, Vol. 35, 2007, p.

In order to solve the above problems, the present invention proposes a solar cell using a p-type oxide semiconductor containing gallium and a manufacturing method thereof.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above problems of the prior art, and it is an object of the present invention to provide a solar cell including an anode, a hole transporting layer, a photoactive layer, an electron transporting layer, and a cathode, Is a p-type oxide semiconductor containing Ga.

The p-type oxide semiconductor may include Ga in CuS and SnO.

The Ga may range from 10 to 70 percent (atomic percent) of the total composition.

The p-type oxide semiconductor may be represented by at least one selected from the following chemical formulas (1), (2) and (3).

[Chemical Formula 1]

CuS _{1 - x} Ga _{x -} SnO

(2)

CuSGa _x Sn _{1 - x} O

(3)

CuSGa _x SnO

In the above formula (1), (2) or (3), 0 < x <

The solar cell may be an organic solar cell using an organic semiconductor.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an anode on a substrate by a vacuum deposition process; Forming a hole transporting layer on the anode by a solution process; Forming a photoactive layer on the hole transporting layer by a solution process; Forming an electron transporting layer on the photoactive layer by a solution process; And forming an electrode on the electron transport layer, wherein the hole transport layer is formed by forming a film of a solution in which a p-type oxide semiconductor containing gallium is mixed with a solvent .

According to the present invention, there is an advantage that a high-performance solar cell can be realized by providing a p-type oxide semiconductor containing gallium as a hole transport layer.

Further, according to the present invention, since p-type oxide semiconductor is manufactured using a solution process, low-temperature and low-cost manufacturing is advantageous.

1 is a cross-sectional structural view showing an organic solar cell according to the present invention.
2 is a diagram showing an energy band diagram when a p-type oxide semiconductor containing gallium and PEDOT: PSS are used according to the present invention.
3 is a graph showing current-voltage characteristics of a solar cell when a p-type oxide semiconductor containing gallium is used and when PEDOT: PSS is used.
4 is a diagram showing external quantum efficiency (EQE) characteristics of a solar cell when a p-type oxide semiconductor containing gallium is used and when PEDOT: PSS is used.
5 is a graph showing current-voltage characteristics of a solar cell in the case where a p-type oxide semiconductor having a different gallium concentration is formed as a hole transport layer according to an embodiment of the present invention.
6 is a graph showing external quantum efficiency characteristics of a solar cell according to gallium concentration.
7 is a CuS-Ga _x Sn _{1 -} a view of the XRD result of the concentration of one Ga 0 to 50% in O _x thin film.
FIG. 8 is an AFM image when the concentration of Ga is 0%, 30%, and 50% in a CuS-Ga _x Sn _{1 - x} O thin film.
9 is a TEM image of a CuS-SnO thin film and (b) an atomic mapping image by EDX (Energy Dispersive X-ray) spectroscopy.
10 is a TEM image of a CuS-Ga _0.5 Sn _0.5 O thin film and (b) an atomic mapping image by EDX (Energy Dispersive X-ray) spectroscopy.
11 is SnO ₂ and _{CuS-Ga x Sn 1 - x} O of the UPS (Ultraviolet Photo Spectroscopy) spectra and work function, Fermi level difference between the valence band, and a view summarizing the values of the ionization potential.
12 is a diagram showing Raman spectrum results of a p-type precursor solution.

First, the terms in the specification of the present invention will be defined.

The solution process includes all existing processes for depositing using liquid solvents such as spin coating, spray coating, dip coating, ink jet printing, roll-to-roll printing, screen printing and the like.

The vacuum deposition process refers to a process in which deposition is performed in a state where a negative pressure is applied and all processes such as sputtering which is a kind of PVD (Physical Vapor Deposition) method, such as CVD (Chemical Vapor Deposition) .

Hereinafter, the present invention will be described in detail with reference to the drawings. It is to be understood, however, that the contents of the drawings are merely shown for the purpose of illustrating the present invention more easily, and the scope of the present invention is not limited to the drawings.

1 is a cross-sectional view illustrating an organic solar cell according to the present invention.

1, an organic solar cell according to the present invention comprises an anode 1, a cathode 2, an electron transport layer 3, a photoactive layer 4, and a hole transport layer 5 .

1, the organic solar battery of the present invention comprises a cathode 2 formed on a substrate (not shown), an electron transport layer 3 formed on the cathode, , A photoactive layer (4), a hole transport layer (5) formed on the photoactive layer, and an anode (1) formed on the hole transport layer are stacked in this order. An organic solar cell having an inverted structure can be understood with reference to Patent Document 1 cited as a background art in the present specification.

The positive electrode 1 or the negative electrode 2 can be formed using a conventionally known vacuum vapor deposition process (CVD) or a paste in which metal flakes or particles are mixed with a binder, A method of printing a metal ink can be used, and a method of forming the positive electrode or the negative electrode is not particularly limited.

The substrate may be any one of a glass substrate, a plastic including PET (polyethylene terephthalate), PEN (polyethylenenaphthhelate), PP (polypropylene), PI (polyamide), TAC (triacetyl cellulose) A flexible substrate including any one of a plastic substrate, an aluminum foil, and a stainless steel foil may be used.

The cathode formed on the substrate is an electrode for providing electrons to the device, and may be an ionized metal material, a metal ink material in a colloid state in a predetermined liquid, a transparent metal oxide, or the like.

The cathode 2 may be deposited in a high vacuum state by a vacuum deposition process or may be formed by a solution or paste process using a metal material used for forming a conventional cathode. The negative electrode forming material is not particularly limited and a conventional negative electrode forming material can be used without limitation. Examples of conventional negative electrode forming materials include aluminum (Al), calcium (Ca), barium (Ba), magnesium (Mg), lithium (Li), cesium (Cs) and the like.

Examples of transparent metal oxides that can form a cathode include indium tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), and aluminum doped zinc oxide have. Here, ITO is generally used as a material for forming the anode, but in the case of the inverted organic solar cell structure, ITO may be used as a material for forming the cathode 2 to form a transparent cathode. In the case of a transparent metal oxide electrode, processes such as sol-gel, spray pyrolysis, sputtering, ALD (atomic layer deposition), and e-beam evaporation are applied .

The electron transport layer 3 is formed between the cathode 2 and the photoactive layer 4 as a layer added for high efficiency of the device by moving the electrons generated in the photoactive layer 4 to the cathode 2.

The electron transporting layer 3 may be formed by blending cesium carbonate to zinc oxide.

The term &quot; blended &quot; as used herein is a self-explanatory term widely used in the art, meaning that two or more materials are dissolved or melted by a solvent and irreversibly mixed.

The blended cesium carbonate content is preferably in the range of 0.5 to 50 parts by volume. .

The electron transport layer 3 can be formed using a solution prepared by mixing zinc oxide (ZnO) and cesium carbonate (Cs ₂ CO ₃ ) in a solvent such as ethanol. This is economical in terms of cost since there is no additional process and time-consuming as compared with the case where cesium carbonate is layer-by-layer formed on the zinc oxide layer.

The photoactive layer (4) contains an organic material and generates electricity by phtovoltaic of the organic material.

The organic material that can be used for the photoactive layer 4 of the present invention is an electron donor material such as P3HT (poly (3-hexylthiophene)), PCDTBT (Poly [N-9'-heptadecanyl-2,7-carbazole- , 5 - (4 ', 7'-di-2-thienyl-2', 1 ', 3'-benzothiadiazole)], PSBTBT (Poly [2,6- (4,4'- dithieno [3,2-b: 2 ', 3'-d] silole) -tart-4,7 (2,1,3-benzothiadiazole)], PTB7 (Poly {4,8-bis [ ) oxy] benzo [1,2-b: 4,5-b '] dithiophene-2,6-diyl-3-fluoro-2- (2-ethylhexyl) carbonyl] thieno [ thiophene-4,6-diyl}), electron acceptor material as is used for the organic, photoactive layer, such as a conventional _{PCBM-C 60 (Phenyl-C61} -butyric acid methyl ester), ICBA (Indene-C60 bis-adduct) Polymeric materials and their derivatives may be used without limitation.

Particularly, it is preferable to use P3HT as an electron donor and PCBM-C ₆₀ as an electron acceptor in a weight ratio of 1: 0.5 to 1: 4.

The photoactive layer 4 is preferably, but not necessarily, a bulk-heterojunction structure in order to enhance the collection efficiency of the separated electron-hole pairs (exicitons).

The hole transport layer 5 is formed between the photoactive layer 4 and the anode 1 to help move the holes generated in the photoactive layer 4 to the anode 1.

According to a preferred embodiment of the present invention, the hole transport layer 5 is formed using a p-type oxide semiconductor containing gallium (Ga) instead of general PEDOT: PSS.

Preferably, the gallium content in the p-type oxide semiconductor may range from 10 to 70 atomic percent.

According to one embodiment of the present invention, the p-type oxide semiconductor may be formed through a solution process, wherein the solvent may be a mixture of 5 to 50 volume percent acetonitrile in ethylene glycol.

According to another embodiment of the present invention, in addition to acetonitrile, at least one of DI water, alcohol, cyclohexane, toluene and an organic solvent may be used.

The p-type oxide semiconductor according to a preferred embodiment of the present invention may be formed by additionally bonding Ga to one or more bonds selected from CuS and SnO, ITO, IZTO, IGZO, and IZO. .

The CuS is copper monosulfide, SnO is tin (II) oxide, ITO is indium tin oxide, IZTO is indium zinc tin oxide, IGZO is Indium Zinc Gallium Oxide, IZO is Indium Zinc Tin Oxide (hereinafter referred to as &quot; Indium Zinc Tin Oxide &quot;), and it is known to those skilled in the art It is self-evident.

The p-type oxide semiconductor according to an embodiment of the present invention may be represented by at least one selected from the following formulas (1), (2) and (3)

[Chemical Formula 1]

CuS _{1 - x} Ga _{x -} SnO

(2)

CuSGa _x Sn _{1 - x} O

(3)

CuSGa _x SnO

In the above formula (1), (2) or (3), 0 < x <

In the p-type oxide semiconductor according to the present invention,

Preparing a precursor solution containing Cu, S, M, and Ga, wherein M is at least one compound selected from SnO, ITO, IZTO, IGZO, and IZO;

Applying the precursor solution onto a substrate; And

And a step of heat-treating the coating layer.

The precursor solution preferably contains [CuTu ₃ ] Cl.

The precursor solution preferably comprises Thiourea.

The step of applying on the substrate may be a vacuum process, a spin coating process, a slot printing process, or an inkjet printing process, but is preferably performed by a spin coating process or an ink jet printing process in terms of process simplicity and cost.

The anode 1 may be formed by a solution process such as screen printing, or a metal paste or a metal ink material in a colloid state in a predetermined liquid, as an electrode for providing holes to the device. Here, the metal paste may be any one of materials such as Ag paste, Al paste, Au paste, and Cu paste, or may be in the form of an alloy. The metal ink material may be at least one of silver (Ag) ink, aluminum (Al) ink, gold (Au) ink, calcium (Ca) ink, magnesium (Mg) ink, lithium (Li) ink and cesium It can be either. The metal material contained in the metal ink material is ionized inside the solution.

The structure of the organic solar cell according to the present invention has been described in detail above. According to another preferred embodiment of the present invention, when a hole transport layer is formed of a p-type oxide semiconductor, such a hole transport layer can be applied not only to organic solar cells including a photoactive layer but also to other organic electronic devices and other solar cells.

A method of fabricating an organic solar cell according to an embodiment of the present invention includes:

Forming an anode on the substrate by a vacuum deposition process;

Forming a hole transporting layer on the anode by a solution process;

Forming a photoactive layer on the hole transporting layer by a solution process;

Forming an electron transporting layer on the photoactive layer by a solution process; And

And forming an electrode on the electron transporting layer,

The hole transporting layer is formed by forming a film of a solution in which a p-type oxide semiconductor containing gallium is mixed with a solvent.

Hereinafter, the present invention will be described in more detail by way of examples. It is to be understood that the following embodiments are for the purpose of illustration only and are not intended to limit the scope of the present invention.

Example

As described below, instead of PEDOT: PSS, a hole transport layer was formed using a p-type oxide semiconductor containing gallium.

Here, the gallium content in the p-type oxide semiconductor is preferably 10 to 70 atomic percent.

Also, the solvent was formed by mixing ethylene glycol and acetonitrile vigorously in a normal atmospheric state, and a p-type oxide semiconductor containing gallium was mixed at a concentration of 0.2M / 16 to prepare a mixed solution.

The above solution was printed on a positive electrode in a nitrogen atmosphere.

FIG. 2 shows energy band diagrams of a p-type oxide semiconductor containing gallium and PEDOT: PSS according to the present invention.

FIG. 2 (a) is an energy band diagram of PEDOT: PSS, and FIG. 2 (b) is an energy band diagram of a p-type oxide semiconductor containing gallium.

In FIG. 2 (a), the HOMO level of PEDOT: PSS is -5.2 eV, and the HOMO level of the p-type oxide semiconductor containing gallium is -5.12 eV in (b) It can be confirmed that the p-type oxide semiconductor according to the embodiment is advantageous.

FIG. 3 and Table 1 show the current-voltage characteristics of the solar cell in the case of using a p-type oxide semiconductor containing gallium and the case of using PEDOT: PSS.

Here, the characteristic values of the solar cell are represented by Jsc, Voc, FF and PCE (Efficiency).

Fig. 3 (a) shows the solar cell characteristics in the dark state, and Fig. 3 (b) shows the solar cell characteristics in the light state.

(Jsc) is the optical short-circuit current density (Jsc), Voc is the optical open-circuit voltage, FF is the Fill Factor, PCE is the energy conversion efficiency and Fill Factor (FF) is the voltage value (Vmax) (Voc x Jsc) and the energy conversion efficiency was calculated as FF x (Jsc x Voc) / Pin and Pin = 100 [mW / cm 2].

Jsc (mA / cm ² ) Voc (V) FF (%) PCE (%) PEDOT: PSS 14.5 0.748 66.9 7.27 CuS-GaSnO 15.0 0.763 69.5 7.97

Referring to FIG. 3 and Table 1, when only PEDOT: PSS was used as the hole transporting layer, the light conversion efficiency was 7.28%.

In contrast, when the p-type oxide semiconductor containing gallium is used, the light conversion efficiency is increased to 7.98%.

4 and Table 2 show the external quantum efficiency (EQE) characteristics of a solar cell in the case of using a p-type oxide semiconductor containing gallium and the case of using PEDOT: PSS.

EQE
(%) EQE
(%) PEDOT: PSS 68.1 at 460 nm 63.0 at 620 nm uS-GaSnO 70.2 at 440 nm 67.0 at 620 nm

Referring to FIGS. 4 and 2, it can be seen that the external quantum efficiency (EQE) is higher than that in the case of using PEDOT: PSS in the case of forming a hole transport layer by printing a p-type oxide semiconductor containing gallium.

5 and Table 3 show the current-voltage characteristics of the solar cell in the case where a p-type oxide semiconductor having a different gallium concentration is formed as a hole transport layer according to an embodiment of the present invention.

FIG. 6 shows external quantum efficiency characteristics of the solar cell according to gallium concentration.

Cu ₄₅ S ₁₀₀ -Ga _x Sn _x O
Ga% Jsc (mA / cm2) Voc (V) FF (%) PCE (%) 10% 15.0 0.753 66.6 7.50 30% 15.0 0.756 67.9 7.71 50% 15.0 0.762 69.0 7.88 70% 15.3 0.745 66.0 7.51 90% 15.1 0.732 64.9 7.19 100% 14.8 0.757 63.5 6.91

Referring to Table 3 and FIGS. 5 to 6, it can be confirmed that the photoelectric conversion efficiency is high when the content of gallium in the p-type oxide semiconductor is 10 to 70 percent.

Hereinafter, a method of manufacturing a p-type oxide semiconductor according to an embodiment of the present invention will be described in detail.

Preparation of precursor solution

Under a nitrogen atmosphere to prepare a precursor solution of _{CuCl 2, NH 2 CSNH 2 (} Thiourea), Ga (NO 3) 3 · xH 2 O (Gallium nitrate hydrate), SnCl 2 dissolved in acetonitrile and ethylene glycol solvents.

Formation of active layer

The prepared precursor solution was spin-coated, then heat-treated on a hot plate at 240 ° C for about 1 minute, or ink-jet printed on a substrate at 60 ° C to form an active layer.

Heat treatment step

The activation layer formed by the above spin coating or inkjet printing was annealed at 300 DEG C under nitrogen atmosphere for about 1 hour.

Semiconductor oxide analysis

7 is a CuS-Ga _x Sn _{1 -} shows a XRD result of the concentration of one Ga 0 to 50% in O _x thin film.

CuS-Ga _x Sn _{1 - x} O has a polycrystalline structure (2? = 28 °, 32 °) and changes from a crystalline state to an amorphous state when the Ga concentration is 30% or more.

8 is a CuS-Ga _x Sn _{1 -} shows an AFM image of when the concentration of Ga 0%, 30%, 50 % in O _x thin film.

When the concentration of Ga was 0%, a needle-like thin film was formed and the value of root-mean-square (RMS) roughness was 23 ~ 90 nm.

However, as the concentration of Ga increased, the value of the root mean square roughness decreased and the thin film quality improved. 30%, 0.46 to 2.5 nm, and at 50%, 0.67 to 3.4 nm.

9 is a TEM image of a CuS-SnO thin film and (b) an atomic mapping image by EDX (Energy Dispersive X-ray) spectroscopy. The CuS-SnO thin film has Cu, S, Sn, and O, respectively, and exhibits a non-uniform thin film crystal structure. This is consistent with the presence of a crystal peak when Ga is 0% in the XRD results of FIG.

10 is a mapping image by atomic _{CuS-Ga 0 .5 Sn 0 .5} O thin film of (a) TEM image and (b) EDX (Energy Dispersive X -ray) spectrometer. _{CuS-Ga 0 .5 Sn 0 .5} O thin film, the presence respectively the Cu, S, Sn, and O, and shows a uniform amorphous structure.

Figure 11 and Table 4, SnO ₂ and CuS-Ga _x Sn _{1 -} table shows the value of (Ultraviolet Photo Spectroscopy) of O _x UPS spectrum and work function, Fermi level and the difference between the valence band, and the ionization potential.

The work function value of 4.63 and 4.61 eV for the thin film crystallized in the CuS-Ga _x Sn _{1 - x} O thin film (Ga <0.3) and the value of ≥4.66 eV for the amorphous thin film (Ga ≥ 0.3) Respectively.

12 shows Raman spectral results of the p-type precursor solution. (a) is a p-type semiconductor region 600-800㎝ ^-1 solution of a Raman spectrum result of 710㎝ ^- if at _{^{1 [Cu (Tu) 3]}} n polymer is formed, the addition of Ga or Sn can be undulated (Wavenumber) Moves to 720 cm ^{& lt;} -1 ^{& gt} ; and Ga or Sn is present in the solution.

(b) shows the Raman spectrum of the 250-450 cm ^-1 region. 290㎝ ^- indicate that the Sn and the Cu present in the ^{1 - 2} Sn In this 340㎝. If Tu is added to the solution or Ca wave number (Wavenumber) 349㎝ ^- and go to ^1, which indicates that Tu is present in the solution.

It will be apparent to those skilled in the art that various modifications and additions may be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (13)

In a solar cell comprising an anode, a hole transporting layer, a photoactive layer, an electron transporting layer, and a cathode,
Wherein the hole transport layer is a p-type oxide semiconductor containing Ga,
Wherein the p-type oxide semiconductor contains Ga in CuS and SnO. delete The method according to claim 1,
Wherein the Ga is in a range of 10 to 70 percent (atomic percent) to the total composition. The method according to claim 1,
Wherein the p-type oxide semiconductor is represented by at least one selected from the following Chemical Formulas (1), (2) and (3).
[Chemical Formula 1]
CuS _1-x Ga _x -SnO
(2)
CuSGa _x Sn _1-x O
(3)
CuSGa _x SnO
In the above formula (1), (2) or (3), 0 < x < The method according to claim 1,
Wherein the solar cell is an organic solar cell using an organic semiconductor. Forming an anode on the substrate by a vacuum deposition process;
Forming a hole transporting layer on the anode by a solution process;
Forming a photoactive layer on the hole transporting layer by a solution process;
Forming an electron transporting layer on the photoactive layer by a solution process; And
And forming an electrode on the electron transporting layer,
The hole transport layer is formed by forming a film of a solution in which a p-type oxide semiconductor containing gallium is mixed with a solvent,
Wherein the p-type oxide semiconductor contains Ga in CuS and SnO. delete The method according to claim 6,
Wherein Ga is in the range of 10 to 70 percent (atomic percent) of the total composition. 9. The method of claim 8,
Wherein the p-type oxide semiconductor is represented by at least one selected from the following Chemical Formulas (1), (2) and (3).
[Chemical Formula 1]
CuS _{1 - x} Ga _{x -} SnO
(2)
CuSGa _x Sn _{1 - x} O
(3)
CuSGa _x SnO
In the above formula (1), (2) or (3), 0 < x < The method according to claim 6,
Wherein the solvent is a mixture of ethylene glycol and at least one of acetonitrile, DI water, alcohol, cyclohexane, toluene and an organic solvent in an amount of 5 to 50 volume percent. The method according to claim 6,
Wherein the p-
(a) preparing a precursor solution containing Cu, S, M, and Ga, wherein M is at least one compound selected from SnO, ITO, IZTO, IGZO, and IZO;
(b) applying the precursor solution onto a substrate to form a coating layer; And
and (c) heat-treating the coating layer. 12. The method of claim 11,
Wherein the precursor solution comprises [CuTu ₃ ] Cl. 12. The method of claim 11,
Wherein the precursor solution comprises Thiourea.

Images