KR102670528B1 - SnO2 ELECTRON TRANSPORT MATERIAL AND OPTOELECTRONIC DEVICE USING THEREOF - Google Patents

Abstract

The electron transport layer according to an embodiment of the present disclosure includes a SnO ₂ layer and SnO ₂ doped with Zn on the SnO ₂ layer.

Description

SnO2 electron transport layer and optical device using the same {SnO2 ELECTRON TRANSPORT MATERIAL AND OPTOELECTRONIC DEVICE USING THEREOF}

The present disclosure relates to a SnO ₂ electron transport layer and an optical device using the same.

The need to develop environmentally friendly and sustainable energy technologies that can respond to climate change is increasing. Optical devices include both photoelectric conversion devices and electro-optical conversion devices, and solar cells, one of the photoelectric conversion devices, are in the spotlight as a sustainable energy technology and a solution that can actively respond to future energy demands. Solar cells are the most basic unit of solar power generation and are semiconductor devices that convert solar energy into electrical energy, using the photovoltaic effect.

However, because today's solar cell technology is not efficient enough to replace future energy demands, technological innovation that goes beyond the current technology level is needed. Accordingly, technologies based on innovative materials such as dye-sensitized solar cells, organic solar cells, quantum dot solar cells, and perovskite solar cells (PSC) have been developed as next-generation solar cells.

Among them, perovskite solar cells have taken a leap forward as one of the thin-film solar cells that can replace conventional silicon solar cells. A perovskite solar cell containing a hole transport material, a light absorbing material, and an electron transport material exhibits a significantly high photovoltaic effect by using the perovskite material as a light absorbing material.

However, perovskite solar cells have many limitations because they are unstable to light, heat, and humidity. For example, SnO ₂ as an electron transport layer is coated in a thin layer, so it is difficult to achieve uniform and dense coating, which poses a problem in terms of long-term stability.

Embodiments disclosed herein provide a SnO ₂ electron transport layer with high efficiency and high durability.

Embodiments disclosed herein provide perovskite optical devices with high efficiency and high durability.

Embodiments disclosed in this specification improve the physical properties of the SnO ₂ electron transport layer by using a SnO ₂ electron transport layer of a bi-layer structure.

Embodiments disclosed in this specification provide a perovskite optical device including a SnO ₂ electron transport layer that has the same level of efficiency as that achieved in a glass device, even when applied to a flexible device.

The electron transport layer according to an embodiment of the present disclosure includes a SnO ₂ layer and a SnO ₂ layer doped with Zn on the SnO ₂ layer.

According to one embodiment of the present disclosure, the SnO ₂ layer and the Zn-doped SnO ₂ layer have a bi-layer structure.

According to one embodiment of the present disclosure, the electron transport layer is formed on the ITO electrode.

According to one embodiment of the present disclosure, the electron transport layer can be used in both flexible devices and glass devices.

According to one embodiment of the present disclosure, the electron transport layer is manufactured through a low temperature process.

According to one embodiment of the present disclosure, the Zn-doped SnO ₂ layer is composed of nanorods.

An optical device according to an embodiment of the present disclosure includes an electron transport layer according to the above-described embodiment.

According to various embodiments of the present disclosure, a SnO ₂ electron transport layer having high efficiency and high durability is provided.

According to various embodiments of the present disclosure, a perovskite optical device having high efficiency and high durability is provided.

According to various embodiments of the present disclosure, the physical properties of the SnO ₂ electron transport layer are improved by using the SnO ₂ electron transport layer with a bi-layer structure.

According to various embodiments of the present disclosure, a perovskite optical device including a SnO ₂ electron transport layer is provided, which has the level of efficiency achieved in a glass device even when applied to a flexible device.

The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Embodiments of the present disclosure will be described with reference to the accompanying drawings described below, in which like reference numerals indicate like elements, but are not limited thereto.
1A and 1B are diagrams showing an electron transport layer (single layer) formed on ITO according to the prior art.
2A and 2B are diagrams showing an electron transport layer (bi-layer) formed on ITO according to an embodiment of the present disclosure.
Figures 3 to 6 correspond to data graphs of single layer and bi-layer measured in glass devices.
Figure 7 corresponds to a bi-layer data graph measured in a flexible device.

Terms used in the present disclosure will be briefly described, and the disclosed embodiments will be described in detail. The terms used in this specification are general terms that are currently widely used as much as possible while considering the functions in the present disclosure, but this may vary depending on the intention or precedent of a technician working in the related field, the emergence of new technology, etc. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the relevant invention. Accordingly, the terms used in this disclosure should be defined based on the meaning of the term and the overall content of the present disclosure, rather than simply the name of the term.

In this disclosure, singular expressions include plural expressions, unless the context clearly specifies the singular. Additionally, plural expressions include singular expressions, unless the context clearly specifies plurality.

In the present disclosure, when a part includes a certain component, this means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

In this disclosure, description of “A and/or B” means A, or B, or A and B.

The term "about" or the like used in the present disclosure is used to encompass tolerance when tolerance exists.

In the present disclosure, the term “at least any one” included in the Markush format expression means including one or more selected from the group consisting of constituent elements described in the Markush format expression.

In the present disclosure, “perovskite” or “PE” refers to a material having a perovskite crystal structure, and may have various perovskite crystal structures in addition to the crystal structure of ABX ₃ .

In the present disclosure, “optical device” is used to include both photoelectric conversion devices and electro-optical conversion devices. For example, optical devices include, but are not limited to, solar cells, light emitting diodes (LEDs), photodetectors, X-ray detectors, and lasers.

In the present disclosure, the term "halide", "halogen", "halogenide" or "halo" refers to a material or composition containing a halogen atom belonging to group 17 of the periodic table in the form of a functional group, for example, chlorine , bromine, fluorine or iodine compounds.

In the present disclosure, the term “layer” refers to a layer having a thickness. The layer may be porous or non-porous. Porosity means having porosity. The layer may have an overall bulk shape or may correspond to a single crystal thin film, but is not limited thereto.

In the present disclosure, when a member is said to be located “on” another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members, unless specifically stated to the contrary. do.

In the present disclosure, when efficiency is simply described without any additional explanation, the efficiency refers to power conversion efficiency (PCE).

In the present disclosure, double layer is used with the same meaning as bi-layer, and double layer and bi-layer may mean a double layer.

In the present disclosure, glass device refers to a device that includes a glass substrate.

Hereinafter, specific details for implementing the present disclosure will be described in detail with reference to the attached drawings. However, in the following description, detailed descriptions of well-known functions or configurations will be omitted if there is a risk of unnecessarily obscuring the gist of the present disclosure.

Advantages and features of the disclosed embodiments and methods for achieving them will become clear by referring to the embodiments described below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the present disclosure is complete and that the present disclosure does not convey the scope of the invention to those skilled in the art. It is provided only for complete information.

In the accompanying drawings, identical or corresponding components are given the same reference numerals. Additionally, in the description of the following embodiments, overlapping descriptions of identical or corresponding components may be omitted. However, even if descriptions of components are omitted, it is not intended that such components are not included in any embodiment.

An optical device according to an embodiment of the present disclosure includes a first electrode, a first charge transport layer formed on the first electrode, a perovskite layer formed on the first charge transport layer, and a second charge transport layer formed on the perovskite layer. , and may include a second electrode formed on the second charge transport layer.

For example, when an optical device is used in a solar cell with an n-i-p structure, the optical device may have a structure in which a first electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a second electrode are sequentially stacked. Alternatively, when the optical device corresponds to a solar cell with a p-i-n structure, the solar cell may have a structure in which a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode are sequentially stacked.

For example, an optical device may have a planar structure, a bi-layer structure, or a meso-superstructure structure. Depending on the structure of the optical device, the shapes of the electrode, charge transport layer, and perovskite layer may be modified.

The electrode includes a first electrode and/or a second electrode and may be an anode or a cathode. The electrode may be an anode or cathode. If the first electrode is an anode, the second electrode may be a cathode. For example, the electrode may be a conductive oxide such as indium-tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide (FTO). Alternatively, the electrode may be silver (Ag), gold (Au), magnesium (Mg), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), nickel (Ni), or palladium. It may include a material selected from the group consisting of (Pd), chromium (Cr), calcium (Ca), samarium (Sm), and lithium (Li), and combinations thereof. Alternatively, the electrode is placed on a flexible and transparent material such as plastic, such as PET (polyethylene terephthalate), PEN (polyethylene naphthelate), PP (polyperopylene), PI (polyimide), PC (polycarbornate), PS (polystylene), and POM (polyoxyethylene). It may be doped with a conductive material.

The electrode may correspond to a material commonly used as an electrode material for a front electrode or back electrode in an optical device. The electrode may be a material selected from one or more of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and composites thereof, but is not limited thereto. For example, the electrode is any one selected from fluorine doped tin oxide (FTO), indium doped tin oxide (ITO), ZnO, CNT (carbon nanotube), and graphene. It may be two or more inorganic conductive electrodes or an organic conductive electrode such as PEDOT:PSS, but is not limited thereto.

As a charge transport layer, an electron transport layer (ETL) or a hole transport layer (HTL) may be formed on the first electrode. When the first charge transport layer is an electron transport layer, the second charge transport layer may correspond to a hole transport layer. Alternatively, when the first charge transport layer is a hole transport layer, the second charge transport layer may correspond to an electron transport layer.

The electron transport layer may correspond to a semiconductor containing “n-type material”. “n-type material” means an electron transport material. The electron transport material may be a single electron transport compound or elemental material, or a mixture of two or more electron transport compounds or elemental materials. The electron transport compound or elemental material may be undoped or doped with one or more dopant elements.

For example, the electron transport layer may be an electronically conductive organic material layer or an electronically conductive inorganic material layer. The electronically conductive organic material may be an organic material used as an n-type semiconductor in a typical organic solar cell. For example, electronically conductive organic materials include fullerenes (C60, C70, C74, C76, C78, C82, C95) and PCBM ([6,6]-phenyl-C61butyric acid methyl ester). and fullerene-derivatives including C71-PCBM, C84-PCBM, PC70BM ([6,6]-phenyl C70-butyric acid methyl ester), polybenzimidazole (PBI), and PTCBI (3,4,9, It may include, but is not limited to, 10-perylenetetracarboxylic bisbenzimidazole), F4-TCNQ (tetra uorotetracyanoquinodimethane), or mixtures thereof.

The electronically conductive inorganic material may be an electronically conductive metal oxide used for electron transfer in conventional quantum dot-based solar cells, dye-sensitized solar cells, or perovskite-based solar cells. In one embodiment, the electronically conductive metal oxide may be an n-type metal oxide semiconductor. For example, n-type metal oxide semiconductors include Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Ba oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, and V. It may be one or more materials selected from oxide, Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide, and SrTi oxide, a mixture thereof, or a composite thereof, but is not limited thereto.

The electron transport layer may be a dense layer (dense film) or a porous layer (porous film). The dense electron transport layer may be a film of the above-described electronically conductive organic material or a dense film of an electronically conductive inorganic material. The electron transport layer of the porous film may be a porous film composed of the particles of the electron-conducting inorganic material described above.

The electron transport layer according to an embodiment of the present disclosure will be described later.

The hole transport layer may correspond to a semiconductor containing “p-type material”. “p-type material” means a hole transporting material. The hole transport material may be a single hole transport compound or elemental material, or a mixture of two or more hole transport compounds or elemental materials. The hole transport compound or elemental material may be undoped or doped with one or more dopant elements. The hole transport material may be an organic hole transport material, an inorganic hole transport material, or a combination thereof.

The hole transport layer may be manufactured through a solution process. The hole transport layer may be a thin film of an organic hole transport material. The thickness of the hole transport layer thin film may be 10 nm to 500 nm, but is not limited thereto.

The hole transport material may correspond to an organic hole transport material, specifically a single molecule to a high molecule organic hole transport material (hole conductive organic material). The polymeric organic hole transport material may include one or more materials selected from thiophene-based, paraphenylenevinylene-based, carbazole-based, and triphenylamine-based materials.

Single to low molecule organic hole transport materials include pentacene, coumarin 6, 3- (2-benzothiazolyl)-7-(diethylamino)coumarin), zinc phthalocyanine (ZnPC), copper phthalocyanine (CuPC), TiOPC (titanium oxide phthalocyanine), Spiro-MeOTAD (2,2',7,7'-tetrakis(N,N-p-dimethoxyphenylamino)- 9,9'-spirobifluorene), F16CuPC (copper(II) 1,2,3, 4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro29H,31H-phthalocyanine), SubPc (boron subphthalocyanine chloride) and N3 (cis-di(thiocyanato)-bis It may include one or more substances selected from (2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II)), but is not limited thereto.

Polymeric organic hole transport materials include 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, SpiroMeOTAD ([2,2′,7,7′-tetrkis(N,N-di-p-methoxyphenyl amine)-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)-2,7diyl-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-benzothiadiazole-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-butylphenyldiphenyl-amine), PIF8-TAA (poly-indenofluoren-8-triarylamine), and their copolymers may include one or two or more selected materials, but are not limited thereto. no.

The electron transport layer or the hole transport layer may correspond to a buffer layer or may include a buffer layer. The surface of the electron transport layer or the hole transport layer may be modified using doping. The electron transport layer or hole transport layer is formed on one side of the electrode through spin coating, dip coating, inkjet printing, gravure printing, spray coating, bar coating, gravure coating, brush painting, thermal evaporation, sputtering, E-Beam, screen printing, blade process, etc. It can be formed by being applied to or coated in a film form.

A method for generating an electron transport layer according to an embodiment of the present disclosure will be described later.

The perovskite layer may be formed to directly contact the first electrode. Alternatively, the perovskite layer can be formed to directly contact the electron transport layer or the hole transport layer. The perovskite layer includes perovskite.

The perovskite layer can be formed through various processes, including a vapor deposition process or a solution process. The perovskite layer can be formed using a vapor deposition process. The vapor deposition process may correspond to a process of supplying a material in a vaporized state or plasma state into a vacuum chamber and depositing the material on the surface of a target object (eg, a substrate). The perovskite layer can be formed through a coating process during the solution process. Coating processes include spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. It may be selected from the group consisting of, but is not limited thereto.

For example, perovskites may contain monovalent organic cations, divalent metal cations, and halogen anions. In one embodiment, the perovskite of the present invention may satisfy the following chemical formula.

[Formula 1]

AMX ₃

In Formula 1, A is a monovalent cation and may correspond to an organic ammonium ion, an amidinium group ion, or a combination of an organic ammonium ion and an amidinium group ion.

For example, the organic cation as A may have the formula (R ₁ R ₂ R ₃ R ₄ N) ⁺ . In this case, R ₁ to R ₄ may correspond to hydrogen, unsubstituted or substituted C1-C20 alkyl, or unsubstituted or substituted aryl.

For example, the organic cation as A may have the formula (R ₅ NH ₃ ) ⁺ , where R ₅ may correspond to hydrogen or substituted or unsubstituted C1-C20 alkyl.

For example, the organic cation as A has the formula (R ₆ R ₇ N=CH-NR ₈ R ₉ ) ⁺ , in which case R ₆ to R ₉ may correspond to hydrogen, methyl, or ethyl.

Additionally, A is a monovalent metal ion and may correspond to an alkali metal ion.

For example, the monovalent metal ion as A may correspond to Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ ion.

Additionally, A may correspond to a combination of a monovalent organic cation and a monovalent metal ion.

For example, A may correspond to a form in which a monovalent metal ion is doped into a monovalent organic cation. The monovalent metal ion, which is a doped metal ion, may include an alkali metal ion, and the alkali metal ion may be one or more selected from Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , and Cs ⁺ ions.

M may be a divalent metal ion. For example, M is 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+ +} a metal cation selected from the group consisting of and combinations thereof, but is not limited thereto.

X may correspond to a halogen ion. For example, the halogen ion includes, but is not limited to, a halogen ion selected from the group consisting of I ^- , Br ^- , F ^- , Cl ^- , and combinations thereof.

For example, the perovskite may be any one or a mixture of two or more selected from CH ₃ NH ₃ PbI ₃ (methylammonium lead iodide, MAPbI ₃ ) and CH(NH ₂ ) ₂ PbI ₃ (formamidinium lead iodide, FAPbI ₃ ).

Below, the electron transport layer according to an embodiment of the present disclosure will be described in more detail.

1A and 1B are diagrams showing an electron transport layer (single layer) formed on ITO according to the prior art. To form the electron transport layer, a SnO ₂ layer may be formed on a transparent electrode (ITO) using a low temperature process of about 300°C, about 250°C, about 200°C, or about 150°C or lower. However, because the formed layer thickness is thin, it is difficult to form a uniform and dense electron transport layer, so long-term stability has been a problem. An image of the surface of the SnO ₂ layer formed as a single layer is shown in Figure 1a, and it can be seen that the layer is thin and not dense. The side of the corresponding electron transport layer is shown in the schematic diagram of FIG. 1B.

2A and 2B are diagrams showing an electron transport layer (bi-layer) formed on ITO according to an embodiment of the present disclosure. An image of the surface of the electron transport layer formed as a bi-layer is shown in Figure 2a, and it can be seen that the layer is thick and relatively dense. The side of the corresponding electron transport layer is shown in the schematic diagram of FIG. 2B.

According to one embodiment of the present disclosure, a SnO ₂ layer is formed on ITO. The thickness of the SnO ₂ layer may be approximately 30 nm, and unit devices may be formed using spin coating (400 rpm/30 s).

Afterwards, a Zn-doped SnO ₂ (Zn:SnO ₂ ) layer is coated on the SnO ₂ layer. The Zn:SnO ₂ layer may be composed of a nano-sized rod. The thickness of the Zn:SnO ₂ layer may be approximately 20 to 30 nm and may be formed using spin coating (4000 rpm/30 s).

The SnO ₂ layer and the SnO ₂ :Zn layer are formed in contact with each other at the top and bottom to have a bi-layer structure. The bi-layer structure can solve the problem of the conventional single-layer SnO ₂ electron transport layer, which has a thin layer and is not dense. In particular, by forming a Zn:SnO ₂ layer composed of nanorods on the SnO ₂ layer, a SnO ₂ electron transport layer with a multi-layer structure having a more dense and uniform thickness can be formed. The diameter of the nanorod may be approximately 2.5 nm, and the length of the nanorod may be approximately 6 to 7 nm.

In order to confirm the difference in performance depending on the structure of the SnO ₂ electron transport layer, a performance comparison was performed between single layer and bi-layer structures based on a glass device, and the results are shown in Figures 3 to 6. .

Single layer (glass element): ITO / SnO ₂ / Perovskite (FAPbI ₃ ) _0.95 (MAPbBr ₃ ) _0.05 / Spiro / Au

Double layer (glass element): ITO / SnO ₂ / Zn:SnO ₂ / Perovskite (FAPbI ₃ ) _0.95 (MAPbBr ₃ ) _0.05 / Spiro / Au

As a result of checking device characteristics through TPV and TPC, the multi-layer structure has overall improved solar cell parameters than the single-layer structure and has an efficiency increase of more than 1%. In addition, it can be seen that the long-term stability of the multi-layer structure is maintained at 90% for 500 hours.

Furthermore, the multi-layer structure applied to the flexible device showed a level of efficiency equivalent to the performance shown when applied to the glass device (see Figure 7).

Double layer (flexible device): ITO (PEN) / SnO ₂ / Zn:SnO ₂ / Perovskite (FAPbI ₃ ) _0.95 (MAPbBr ₃ ) _0.05 / Spiro / BABr / Au

The measurement data shown in FIGS. 3 to 7 were measured using the following method.

1) Current-voltage characteristics: Using an artificial solar device (ORIEL class A solar simulator, Newport, model 91195A) and source-meter (source-meter, Kethley, model 2420), open-circuit voltage (VOC) and short-circuit current density JSC) and fill factor (FF) were measured.

2) Photoelectric conversion efficiency (PCE, η): A perovskite optical device manufactured under constant temperature and humidity conditions of 1,000 W/㎡ solar radiation intensity, temperature of 85℃, and humidity of 85% is used as a light source with a wavelength of 280 to 2500 nm. The PCE value was measured by exposure to .

3) Charge transfer characteristics of the hole transport layer according to additives: Charge transfer characteristics were measured using current-voltage characteristics.

The preferred embodiments of the present invention described above have been disclosed for illustrative purposes, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions will be possible. should be regarded as falling within the scope of the patent claims.

Those of ordinary skill in the technical field to which the present invention pertains can make various substitutions, modifications and changes without departing from the technical spirit of the present invention. Therefore, the present invention is limited to the above-described embodiments and the accompanying drawings. It is not limited by

Claims (7)

As an electron transport layer,
SnO ₂ layer; and
SnO ₂ layer doped with Zn on the SnO ₂ layer
Including,
The SnO ₂ layer and the Zn-doped SnO ₂ layer have a bi-layer structure,
The Zn-doped SnO ₂ layer is an electron transport layer composed of nanorods.
delete According to paragraph 1,
The electron transport layer is formed on an ITO electrode.
According to paragraph 1,
The electron transport layer is an electron transport layer that can be used in both flexible devices and glass devices.
According to paragraph 1,
The electron transport layer is an electron transport layer that can be manufactured through a low temperature process.
delete An optical device comprising an electron transport layer according to any one of claims 1 and 3 to 5.