Optical device having tin oxide-based electron transport layer

Abstract

The present disclosure relates to an optical device having a tin oxide-based electron transport layer. The optical device having a tin oxide-based electron transport layer comprises: a first electrode; a first charge transport layer formed on the first electrode; a perovskite layer formed on the first charge transport layer; a second charge transport layer formed on the perovskite layer; and a second electrode formed on the second charge transport layer, wherein the first charge transport layer is an electron transport layer and includes a bi-layer structure of a sol-gel-based SnO2 layer and an SnO2 nanoparticle layer.

Description

Optical device having a tin oxide-based electron transport layer

[0001] The present disclosure relates to an optical device having an electron transport layer based on tin oxide, and more particularly, to an optical device including an electron transport layer having a bi-layer structure of a sol-gel based SnO2 layer and a SnO2 nanoparticle layer.

[0002] The need to develop environmentally friendly and sustainable energy technologies that can address climate change is growing. Photovoltaic devices encompass both photovoltaic and electro-optical conversion devices. Solar cells, one type of photovoltaic device, are attracting attention as a sustainable energy technology and a solution that can proactively meet future energy demands. Solar cells are semiconductor devices that convert solar energy into electrical energy, utilizing the photovoltaic effect.

[0003] However, current solar cell technology is not efficient enough to meet future energy demands, necessitating technological innovations that surpass current standards. To address this, innovative materials-based technologies such as dye-sensitized solar cells, organic solar cells, quantum dot solar cells, and perovskite solar cells (PSCs) have been developed as next-generation solar cells.

[0004] Among these, perovskite solar cells have emerged as a key player in thin-film solar cells, potentially replacing conventional silicon solar cells. Containing a hole-transporting material, a light-absorbing material, and an electron-transporting material, perovskite solar cells utilize perovskite materials as light-absorbing materials, demonstrating remarkably high photovoltaic efficiency.

[0005] Meanwhile, when solar cells generate electricity, some of the electrons and holes generated during photovoltaic power generation can recombine, generating what's known as dark current. This refers to the leakage current. Higher dark currents decrease solar cell efficiency, so methods to reduce dark current by inhibiting electron-hole recombination are being discussed.

[0006] The present disclosure aims to provide an optical device having improved efficiency by including a tin oxide-based electron transport layer.

[0007] An optical device having a tin oxide-based electron transport layer according to one 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, a second charge transport layer formed on the perovskite layer, and a second electrode formed on the second charge transport layer, wherein the first charge transport layer includes a bi-layer structure of a sol-gel-based SnO2 layer and a SnO2 nanoparticle layer as an electron transport layer.

[0008] According to one embodiment of the present disclosure, the sol-gel based SnO2 layer is formed by cross-linking.

[0009] According to one embodiment of the present disclosure, cross-linking is achieved by reaction between GPTMS (3-(2,3-Epoxypropoxy)propyltrimethoxysilane) and ED (ethylenediamine).

[0010] According to one embodiment of the present disclosure, crosslinks are formed by GPTMS and ED in a ratio of 1:1 to 1:2.

[0011] According to one embodiment of the present disclosure, the precursor used in the sol-gel based SnO2 layer comprises Sn(acac)2.

[0012] An optical module is provided, manufactured by combining a plurality of optical elements according to one embodiment of the present disclosure.

[0013] A tin oxide-based electron transport layer according to one embodiment of the present disclosure includes a sol-gel-based SnO2 layer and a SnO2 nanoparticle layer.

[0014] An optical device having a tin oxide-based electron transport layer according to one 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, a second charge transport layer formed on the perovskite layer, and a second electrode formed on the second charge transport layer, wherein the first charge transport layer includes a sol-gel-based SnO2 layer formed by cross-linking as an electron transport layer.

[0015] By using various embodiments of the present disclosure, dark current generated in an optical device can be reduced by suppressing recombination of electrons and holes.

[0016] By using various embodiments of the present disclosure, the efficiency of a solar cell can be improved by reducing leakage current.

[0017] The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs (hereinafter referred to as “ordinary skilled person”) from the description of the claims.

[0018] FIG. 1 is a drawing showing the structure of an optical device according to one embodiment of the present disclosure.

[0019] FIG. 2 is a drawing showing a scanning electron microscope (SEM) image of an electron transport layer of an optical device according to one embodiment of the present disclosure.

[0020] FIG. 3 is a diagram showing a dark current generated in an electron transport layer according to one embodiment of the present disclosure.

[0021] FIG. 4 is a diagram showing a TCSPC (Time-Correlated Single Photon Counting) spectrum of an electron transport layer according to one embodiment of the present disclosure.

[0022] FIG. 5 is a diagram showing the difference in electrical characteristics of an optical device depending on whether an additive is introduced into an electron transport layer according to one embodiment of the present disclosure.

[0023] FIG. 6 is a drawing showing an optical module manufactured by combining a plurality of optical elements according to one embodiment of the present disclosure.

[0024] FIGS. 7 and 8 are diagrams showing electrical characteristics of a large-area optical module including an electron transport layer introducing an additive according to one embodiment of the present disclosure.

[0025] FIG. 9 is a diagram showing electrical characteristics of an optical device according to an electrode component of the optical device according to one embodiment of the present disclosure.

[0026] Hereinafter, specific details for implementing the present disclosure will be described in detail with reference to the attached drawings. However, in the following description, specific descriptions of widely known functions or configurations will be omitted if they may unnecessarily obscure the gist of the present disclosure.

[0027] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0028] The term "about" used throughout this specification is used to encompass the tolerance when there is a tolerance.

[0029] Throughout this specification, the term "at least one" in a Markush format expression means including one or more selected from the group consisting of components described in the Markush format expression.

[0030] Throughout this specification, references to “A and / or B” mean “A, or B, or A and B.”

[0031] In the present disclosure, “perovskite” or “PE” means a material having a perovskite crystal structure, and may have various perovskite crystal structures in addition to the crystal structure of ABX3.

[0032] In the present disclosure, the term "optical device" is used to mean both a photoelectric conversion device and an electro-optical conversion device. For example, the optical device includes, but is not limited to, a solar cell, a light emitting diode (LED), a photodetector, an X-ray detector, and a laser.

[0033] In the present disclosure, the term “halide,” “halogen,” “halide,” or “halo” means a material or composition containing a halogen atom belonging to group 17 of the periodic table in the form of a functional group, which may include, for example, chlorine, bromine, fluorine, or iodine compounds.

[0034] Throughout this specification, the term "layer" refers to a layer having a thickness. The layer may be porous or non-porous. Porosity refers to having a void ratio. The layer may have a bulk form as a whole or may correspond to a single crystal thin film, but is not limited thereto.

[0035] Throughout this specification, when a member is said to be located "on" another member, unless otherwise specifically stated, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0036] Throughout this specification, where efficiency is simply described without further explanation, the efficiency may refer to power conversion efficiency (PCE).

[0037] Hereinafter, specific details for implementing the present disclosure will be described in detail with reference to the attached drawings. However, in the following description, specific descriptions of widely known functions or configurations will be omitted if they may unnecessarily obscure the gist of the present disclosure.

[0038] The advantages and features of the disclosed embodiments, and methods for achieving them, will become clearer with reference to the embodiments described below, along with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure the completeness of the disclosure and to fully inform those skilled in the art of the scope of the invention.

[0039] In the attached drawings, identical or corresponding components are assigned the same reference numerals. Furthermore, in the description of the embodiments below, duplicate descriptions of identical or corresponding components may be omitted. However, even if a description of a component is omitted, it is not intended that such component is not included in any embodiment.

[0040] An optical device according to one embodiment of the present disclosure may include a first electrode, a first charge transport layer formed on the first electrode, a perovskite layer formed on the first charge transport layer, a second charge transport layer formed on the perovskite layer, and a second electrode formed on the second charge transport layer.

[0041] For example, when the photonic device is used in a solar cell having a nip structure, the photonic device may have a structure in which a first electrode, an electron transport layer (a first charge transport layer), a perovskite layer, a hole transport layer (a second charge transport layer), and a second electrode are sequentially stacked. Or, when the photonic device corresponds to a solar cell having a pin structure, the photonic device may have a structure in which a first electrode, a hole transport layer (a first charge transport layer), a perovskite layer, an electron transport layer (a second charge transport layer), and a second electrode are sequentially stacked.

[0042] For example, the photonic device may have a planar structure, a bilayer structure, or a meso-superstructure structure. Depending on the structure of the photonic device, the shapes of the electrodes, charge transport layer, and perovskite layer may be modified.

[0043] For example, when the photonic device has a bi-layer structure, the perovskite layer may have a bi-layer structure formed by filling porous TiO2 with perovskite to form a layer. The bi-layer may refer to a structure composed of a first layer of a TiO2: Perovskite mixed layer in which all of the pores of the porous TiO2 are filled with perovskite, and a second layer of a pure perovskite layer thereon.

[0044] The electrode comprises a first electrode and / or a second electrode, and may be an anode or a cathode. The electrode may be an anode or a cathode. If the first electrode is an anode, the second electrode may be a cathode. Alternatively, if the first electrode is a cathode, the second electrode may be an anode. For example, the electrode may be a conductive oxide such as indium-tin oxide (ITO), indium-zinc oxide (IZO), flourine-doped tin oxide (FTO), or the like. Alternatively, the electrode may comprise a material selected from the group consisting of silver (Ag), gold (Au), magnesium (Mg), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), nickel (Ni), palladium (Pd), chromium (Cr), calcium (Ca), samarium (Sm), and lithium (Li), and combinations thereof. Alternatively, the electrode may correspond to a flexible and transparent material such as plastic, such as polyethylene PET (polyethylene terephthalate), PEN (polyethylene naphthelate), PP (polyperopylene), PI (polyimide), PC (polycarbornate), PS (polystylene), POM (polyoxyethylene), etc., in which a conductive material is doped.

[0045] The electrode may correspond to a material commonly used as an electrode material for a front electrode or a back electrode in a photonic 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 a composite thereof, but is not limited thereto. For example, the electrode may be one or more inorganic conductive electrodes selected from fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), ZnO, carbon nanotubes (CNT), and graphene, or may correspond to an organic conductive electrode such as PEDOT:PSS, but is not limited thereto.

[0046] As a charge transport layer, an electron transport layer (ETL) or a hole transport layer (HTL) may be formed on the first electrode. If the first charge transport layer is an electron transport layer, the second charge transport layer may correspond to a hole transport layer. Alternatively, if the first charge transport layer is a hole transport layer, the second charge transport layer may correspond to an electron transport layer.

[0047] The electron transport layer may correspond to a semiconductor comprising an "n-type material." The "n-type material" refers to 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.

[0048] For example, the electron transport layer may be an electron-conducting organic layer or an electron-conducting inorganic layer. The electron-conducting organic layer may be an organic layer used as an n-type semiconductor in a typical organic solar cell. For example, the electron-conducting organic layer may include, but is not limited to, fullerenes (C60, C70, C74, C76, C78, ​​C82, C95), 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), PBI (polybenzimidazole), PTCBI (3,4,9,10-perylenetetracarboxylic bisbenzimidazole), F4-TCNQ (tetrafluorotetracyanoquinodimethane), or mixtures thereof.

[0049] The electron-conducting inorganic material may be an electron-conducting metal oxide used for electron transport in a typical quantum dot-based solar cell, dye-sensitized solar cell, or perovskite solar cell. In one embodiment, the electron-conducting metal oxide may be an n-type metal oxide semiconductor. For example, the n-type metal oxide semiconductor may be a material selected from, but not limited to, one or more of 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, V oxide, Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide, and SrTi oxide, a mixture thereof, or a composite thereof.

[0050] 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 electron-conducting organic material described above or a dense film of an electron-conducting inorganic material. The electron transport layer of the porous film may be a porous film composed of particles of the electron-conducting inorganic material described above.

[0051] The hole transport layer may correspond to a semiconductor comprising a "p-type material." The "p-type material" refers to a hole transport 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.

[0052] The hole transport layer may be manufactured using 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 range from 10 nm to 500 nm, but is not limited thereto.

[0053] The hole transport material may be an organic hole transport material, specifically a single molecule or polymer organic hole transport material (hole conducting organic material). The polymer organic hole transport material may include one or more materials selected from thiophene-based, paraphenylenevinylene-based, carbazole-based, and triphenylamine-based compounds.

[0054] Single-molecule to small-molecule organic hole transport materials include pentacene, coumarin 6 (coumarin 6, 3- (2-benzothiazolyl)-7- (diethylamino)coumarin), zinc phthalocyanine (ZnPC), copper phthalocyanine (CuPC), titanium oxide phthalocyanine (TiOPC), Spiro-MeOTAD (2,2',7,7'-tetrakis(N,Np-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), and boron subphthalocyanine chloride (SubPc). It may include one or more substances selected from N3(cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II)), but is not limited thereto.

[0055] 고분자 유기 정공 수송물질은, 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 ([2,22′,7,77′-tetrkis (N,N-di-p-methoxyphenyl amine)-9,9,9′-spirobi fluorine]), PCPDTBT(Poly[2,1,3-benzothiadiazole- 4,7-diyl[4,4-bis(2-ethylhexyl-4H- cyclopenta [2,1-b:3,4- b']dithiophene-2,6-diyl]], Si-PCPDTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)- 2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PBDTTPD(poly((4,8-diethylhexyloxyl) benzo([1,2- b:4,5-b']dithiophene)-2,6-diyl)-alt-((5-octylthieno[3,4-c]pyrrole-4,6-dione)-1,3-diyl)), PFDTBT(poly[2,7-(9-(2-ethylhexyl)-9-hexyl-fluorene)-alt-5,5-(4', 7, -di-2-thienyl-2',1',3'-benzothiadiazole)]), PFO-DBT(poly[2,7-.9,9-(dioctyl-fluorene)-alt-5,5-(4',7'-di-2-.thienyl-2', 1', 3'-benzothiadiazole)]), PSiFDTBT(poly[(2,7-dioctylsilafluorene)-2,7-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5′-diyl]), PSBTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)- 2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PCDTBT(Poly [[9-(1-octylnonyl)-9H-carbazole-2,7- diyl] -2,5-thiophenediyl -2,1,3-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) and copolymers thereof may include one or more selected from the group consisting of, but is not limited thereto.

[0056] The electron transport layer or hole transport layer may be surface-modified by doping. The electron transport layer or hole transport layer may be formed by applying it to one surface of the electrode or coating it in the form of a film 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.

[0057] 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 in which a material is supplied in a vaporized or plasma state into a vacuum chamber and the material is deposited on a surface of a target object (e.g., a substrate). The perovskite layer can be formed through a coating process during the solution process. The coating process may be selected from the group consisting of, but is not limited to, spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof.

[0058] For example, the perovskite may contain a monovalent organic cation, a divalent metal cation, and a halogen anion. In one embodiment, the perovskite of the present invention may satisfy the following chemical formula:

[0059]

[0060] [Chemical Formula 1]

[0061] AMX3

[0062]

[0063] In chemical formula 1, A is a monovalent cation, which may correspond to an organic ammonium ion, an amidinium group ion, or a combination of an organic ammonium ion and an amidinium group ion.

[0064] For example, an organic cation as A has the chemical formula (R1R2R3R4N) + may have. In this case, R1~R4 may correspond to hydrogen, unsubstituted or substituted C1-C20 alkyl, or unsubstituted or substituted aryl.

[0065] For example, an organic cation as A has the chemical formula (R5NH3) + , wherein R5 may correspond to hydrogen, or substituted or unsubstituted C1-C20 alkyl.

[0066] For example, an organic cation as A has the chemical formula (R6R7N=CH-NR8R9) + , and in this case, R6~R9 can correspond to hydrogen, methyl, or ethyl.

[0067] M can be a divalent metal ion. For example, M can be 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, but not limited to, and combinations thereof.

[0068] X may correspond to a halogen ion. For example, the halogen ion is I - , Br - , F - , Cl -and combinations thereof. Including, but not limited to, a halogen ion selected from the group consisting of:

[0069] For example, the perovskite may be one or a mixture of two or more selected from CH3NH3PbI3 (methylammonium lead iodide, MAPbI3) and CH(NH2)2PbI3 (formamidinium lead iodide, FAPbI3).

[0070] FIG. 1 is a diagram illustrating the structure of an optical device according to one embodiment of the present disclosure. In one embodiment, the first electrode and the second electrode may be composed of FTO (Fluorine doped Tin Oxide) and Au, respectively.

[0071] In one embodiment, the hole transport layer may include Spiro-OMeTAD. Holes generated in the perovskite layer can travel through the hole transport layer to the electrode.

[0072] In one embodiment, a diffusion barrier layer (not shown in the drawing) is disposed between the hole transport layer and the electrode to suppress diffusion of the electrode, thereby improving the stability of the optical device. According to one embodiment, the diffusion barrier layer may be disposed between the hole transport layer and the Au electrode.

[0073] In one embodiment, the electron transport layer may include tin oxide. For example, the electron transport layer may include a bilayer structure of a sol-gel based SnO2 layer and a SnO2 nanoparticle layer. Each of the sol-gel based SnO2 layer and the SnO2 nanoparticle layer forming the bilayer structure may be formed by, but is not limited to, spin coating or blade coating, and may be formed by various coating methods.

[0074] In one embodiment, the sol-gel based SnO2 layer can be formed by coating a precursor (e.g., Sn(acac)2) at a concentration of 2.5 to 50 mM, followed by heat treatment at 150 to 180 degrees Celsius. For example, the sol-gel based SnO2 layer can be formed by spin coating a precursor at a concentration of 10 mM at 2000 rpm for 30 seconds, followed by heat treatment at 160 degrees Celsius for 1 hour.

[0075] In one embodiment, the SnO2 nanoparticle layer can be formed by coating a solution in which the SnO2 nanoparticle stock solution and water are mixed in a volume ratio of 1:5 to 1:10, and then heat-treating at 100 degrees Celsius or higher. For example, the SnO2 nanoparticle layer can be formed by spin-coating a solution in which the SnO2 nanoparticle stock solution and water are mixed in a volume ratio of 1:5 at 3000 rpm for 30 seconds, and then heat-treating at 100 degrees Celsius for 30 minutes.

[0076] At this time, the sol-gel-based SnO2 layer can be formed by a precursor containing Sn(acac)2 as shown in the chemical formula 1 below. Through this configuration, the recombination of electrons and holes generated in the perovskite layer is partially suppressed, thereby reducing the dark current and thus increasing the efficiency of the photonic device.

[0077]

[0078] Additionally, the sol-gel-based SnO2 layer can be formed by cross-linking. At this time, the cross-linking can be formed by adding GPTMS (3-(2,3-Epoxypropoxy)propyltrimethoxysilane) and ED (ethylenediamine), which are additives, at a molar ratio of up to 100% relative to Sn(acac)2, and then undergoing a polymerization process during a heat treatment process. At this time, the coating and heat treatment conditions can be the same regardless of whether the cross-linking agent is added. In one embodiment, the cross-linking can be formed by the additives GPTMS and ED at a ratio of 1:1 to 1:2, and as the cross-linking is formed, surface defects of the electron transport layer are reduced, so that charges generated by sunlight can be maintained for a longer period of time without recombination, thereby further increasing the efficiency of the photovoltaic device.

[0079]

[0080] Performance comparison

[0081] The performance of the optical device was evaluated using the following method using a perovskite optical device in which additives including GPTMS and ED were introduced into the electron transport layer at different molar ratios relative to Sn(acac)2, and the results of testing while changing the molar ratio of the additives in the optical device structure below are shown in Table 1 below.

[0082]

[0083] Optical device structure: Glass / FTO / Sol-gel SnO2 / SnO2NPs / (FAPbI3) 0.95 (MAPbBr3) 0.05 Perovskite / Spiro-OMeTAD / MoO3 / ITO / Au

[0084] 1) Current-voltage characteristics: Using an artificial sun device (ORIEL class A solar simulator, Newport, model 91195A) and a source-meter (source-meter, Kethley, model 2420), the AM1.5G spectrum light was irradiated through the artificial sun device with an irradiance of 1,000 W / ㎡, and the voltage was applied in both directions (Reverse / Forward) and the current was measured, and the open circuit voltage (V) was measured. OC ), short-circuit current density (J SC ) and fill factor (FF) were measured.

[0085] 2) Power conversion efficiency (PCE): The final power conversion efficiency was obtained by multiplying the values ​​of open circuit voltage, short circuit current density, and fill factor calculated from the current-voltage characteristics.

[0086] 3) Stability: Stability was evaluated by inputting the measured PCE value into the following calculation formula.

[0087] Calculation formula = (η1 / η0) x 100

[0088] In the calculation formula, η0 represents the initial photoelectric conversion efficiency of the perovskite optical device immediately after the stability test begins, and η1 represents the photoelectric conversion efficiency measured after a certain period of time after the same perovskite optical device is continuously irradiated with the AM1.5G spectrum and 1 Sun light intensity of an artificial solar device.

[0089] 4) Maximum power point tracking (MPPT): In the case of light irradiance stability results, the voltage indicating the maximum output was continuously detected and tracked, thereby indicating the relative maximum output value that changes over time.

[0090]

[0091] Molar ratio of additives V oc (V)J sc (mA / cm 2)F.Fη(%)No additives1.1124.510.8422.8520% molar ratio compared to Sn(acac)21.1524.980.8123.2950% molar ratio compared to Sn(acac)21.1624.920.8424.03100% molar ratio compared to Sn(acac)21.1724.930.8324.20

[0092] In Table 1, it can be confirmed that the efficiency of the optical device further increases when an additive is introduced, and that the efficiency is improved as the molar ratio of the additive increases up to 100%. FIG. 2 is a drawing showing a scanning electron microscope (SEM) image of the electron transport layer of the optical device according to an embodiment of the present disclosure. As shown in FIG. 2, the electron transport layer (Sn(acac)2-XL-bilayer) having a bilayer structure including a sol-gel-based SnO2 layer and a SnO2 nanoparticle layer and having an additive introduced therein can be confirmed to uniformly cover the entire area of ​​the first electrode (e.g., FTO) compared to a bare cell, a sol-gel-based SnO2 layer, a SnO2 nanoparticle layer (NPs), and a sol-gel-based SnO2 layer having an additive introduced at a molar ratio of 50% to Sn(acac)2. Through this configuration, the electron transport layer of the double-layer structure can smoothly transport electrons generated in the perovskite layer and prevent unwanted non-luminous recombination of electrons and holes by preventing the holes from directly contacting the first electrode.

[0093] FIG. 3 is a diagram showing dark current generated in an electron transport layer according to an embodiment of the present disclosure. In FIG. 3, it can be confirmed that a lower dark current is generated in a sol-gel-based electron transport layer (acac2) using Sn(acac)2, compared to an electron transport layer (cl2) using a SnCl2 precursor or an electron transport layer (cl2acac2) using a SnCl2(acac)2 precursor. Additionally, it can be confirmed that a lower dark current is generated even when an additive is introduced into the sol-gel-based SnO2 layer (acac2-XL).

[0094] FIG. 4 is a diagram showing a Time-Correlated Single Photon Counting (TCSPC) spectrum of an electron transport layer according to an embodiment of the present disclosure. In FIG. 4, it can be confirmed that the lifetime of excited carriers is longer in the electron transport layer (acac2) using the Sn(acac)2 precursor, compared to the electron transport layer (cl2) using the SnCl2 precursor or the electron transport layer (cl2acac2) using the SnCl2(acac)2 precursor. In particular, when an additive is introduced (acac2-XL20, acac-XL50), it can be confirmed that the lifetime of excited carriers is further extended. That is, it can be confirmed that the surface defects of the electron transport layer are reduced by the sol-gel-based SnO2 layer using the Sn(acac)2 precursor and the introduction of the additive, so that the charges generated by sunlight are maintained for a longer period of time.

[0095] FIG. 5 is a diagram showing the difference in electrical characteristics of an optical device depending on whether an additive is introduced into an electron transport layer according to one embodiment of the present disclosure.

[0096] In Fig. 5 (a), it can be confirmed that the average light irradiation stability is improved in the optical device (XL) with the additive introduced into the electron transport layer, compared to the optical device (Reference) with no additive introduced into the electron transport layer.

[0097] In Fig. 5 (b), it can be confirmed that the optical element (XL) with the additive introduced has a lower capacitance at low frequencies than the optical element (Reference) without the additive introduced. In other words, it can be confirmed that the stability of the optical element is improved by suppressing ion migration due to the introduction of the additive.

[0098] In Fig. 5 (c), it can be confirmed that the transient photocurrent (TPC) value decays at a faster rate in the optical device (XL) with the additive introduced compared to the optical device (Reference) without the additive introduced. In other words, it can be confirmed that the current is transported more effectively in the electron transport layer with the additive introduced.

[0099] FIG. 6 is a diagram showing an optical module manufactured by combining a plurality of optical elements according to an embodiment of the present disclosure, and FIGS. 7 and 8 are diagrams showing electrical characteristics of a large-area optical module including an electron transport layer introducing an additive according to an embodiment of the present disclosure. In FIG. 6, five optical elements are illustrated as being connected in series, but the present invention is not limited thereto, and an optical module may be manufactured by combining any number of optical elements. In FIGS. 7 and 8, it can be confirmed that a high efficiency of 20% is exhibited even in a large-area optical module by using an electron transport layer introducing an additive.

[0100] FIG. 9 is a diagram showing the electrical characteristics of an optical device according to an electrode component of the optical device according to an embodiment of the present disclosure. In FIG. 9, it can be confirmed that an optical device including a tin oxide-based electron transport layer according to an embodiment of the present disclosure has high efficiency regardless of the component (FTO or ITO) of the first electrode.

[0101] The preceding description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to various modifications without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0102] While the present disclosure has been described in connection with certain embodiments herein, it should be understood that various modifications and variations can be made without departing from the scope of the present disclosure, which would be apparent to those skilled in the art. Furthermore, such modifications and variations are intended to fall within the scope of the claims appended to this specification.

Claims

1. An optical device having an electron transport layer based on tin oxide, First electrode; A first charge transport layer formed on the first electrode; A perovskite layer formed on the first charge transport layer; A second charge transport layer formed on the perovskite layer; and A second electrode formed on the second charge transport layer Including, An optical device, wherein the first charge transport layer includes a bi-layer structure of a sol-gel based SnO2 layer and a SnO2 nanoparticle layer as an electron transport layer.

2. In paragraph 1, The above sol-gel based SnO2 layer is an optical device formed by cross-linking.

3. In paragraph 2, The above cross-linking is an optical element that reacts and bonds with GPTMS (3-(2,3-Epoxypropoxy)propyltrimethoxysilane) and ED (ethylenediamine).

4. In paragraph 3, The above cross-linking is formed by GPTMS and ED in a ratio of 1:1 to 1:2, and is an optical device.

5. In paragraph 1, A photonic device in which the precursor used in the above sol-gel based SnO2 layer comprises Sn(acac)2.

6. An optical module manufactured by combining a plurality of optical elements according to paragraph 1.

7. As a tin oxide-based electron transport layer, sol-gel based SnO2 layer; and SnO2 nanoparticle layer An electron transport layer comprising:

8. An optical device having an electron transport layer based on tin oxide, First electrode; A first charge transport layer formed on the first electrode; A perovskite layer formed on the first charge transport layer; A second charge transport layer formed on the perovskite layer; and A second electrode formed on the second charge transport layer Including, An optical device, wherein the first charge transport layer comprises a sol-gel based SnO2 layer formed by cross-linking as an electron transport layer.

9. In paragraph 8, The above cross-linking is an optical element that reacts and bonds with GPTMS (3-(2,3-Epoxypropoxy)propyltrimethoxysilane) and ED (ethylenediamine).

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