KR102227722B1 - Electron transport material for optoelectronic devices and optoelectronic devices comprising same - Google Patents

Abstract

The present invention relates to an electron transport material for an optoelectronic device, including: at least one polymeric electron transport material selected from the group consisting of poly(ethyleneimine) (PEI) and poly(ethyleneimine)ethoxylated (PEIE); and a fatty acid. The electron transport material shows excellent resistance against mechanical deformation, can be used for a flexible optoelectronic device, and provides an optoelectronic device with excellent efficiency and stability.

Description

Electron transport material for optoelectronic devices and optoelectronic devices comprising same

The present invention relates to an electron transport material for an optoelectronic device and an optoelectronic device including the same.

In general, an electronic device such as an organic light emitting device or an organic solar cell includes two electrodes facing each other and an electron transport layer between the electrodes.

As the electron transport layer material in organic photoelectric devices such as OLED and OPV, ZnO and PEIE are typically used.

However, these electron transport materials are insufficient in terms of the efficiency of the photoelectric device, and have limitations in terms of long-term safety and mechanical flexibility as a flexible photoelectric device.

Accordingly, as a material for the electron transport layer in the existing photoelectric device, a new material is required.

An object of the present invention is to provide a photoelectric device having flexibility and excellent performance by using an electron transport material for a photoelectric device including a fatty acid and a polymer electron transport material.

In order to achieve the above object, in one aspect of the present invention

At least one polymer electron transport material selected from the group consisting of polyethyleneimine (Poly(ethyleneimine), PEI) and polyethyleneimine ethoxylated (Poly(ethyleneimine)-ethoxylated, PEIE); And

fatty acid;

An electron transport material for an optoelectronic device comprising a is provided.

In addition, in another aspect of the present invention

There is provided a method for manufacturing an electron transport material comprising the step of replacing a polymer with a fatty acid.

In addition, in another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer including an electron transport material for the photoelectric device, positioned between the first electrode and the second electrode; And

A photoelectric conversion layer positioned between the first electrode and the second electrode;

An optoelectronic device comprising a is provided.

In addition, in another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And

A light emitting layer positioned between the first electrode and the second electrode;

An organic light-emitting device comprising a is provided.

Furthermore, in another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And

A photoactive layer positioned between the first electrode and the second electrode;

An organic solar cell comprising a is provided.

The electron transport material provided in one aspect of the present invention has excellent properties against mechanical deformation, and thus can be used for a flexible photoelectric device, and has an effect of excellent efficiency and stability of the photoelectric device.

1 is a schematic diagram of an organic light emitting device and an organic solar cell manufactured according to an embodiment of the present invention,
Figure 2 shows a schematic diagram of the process of forming a PEIE substituted with a fatty acid prepared according to a preparation example of the present invention,
3 is a JVL curve of an organic light-emitting device according to an exemplary embodiment of the present invention, and is a graph showing current density and luminance according to voltage,
4 is a graph showing power efficiency of an organic light emitting device of an embodiment according to an experimental example of the present invention, and is a graph showing power efficiency according to luminance,
5 is a graph showing a photocurrent density according to voltage of an organic solar cell of an Example and a Comparative Example according to an experimental example of the present invention,
6 is a graph showing external quantum efficiency (EQE) according to wavelengths of organic solar cells of an embodiment and a comparative example according to an experimental example of the present invention,
7 is a graph showing a Nyquist plot of an organic solar cell of an Example and a Comparative Example according to an experimental example of the present invention,
8 is a graph showing a photocurrent density according to voltage of a solar cell module including an organic solar cell of an embodiment and a comparative example according to an experimental example of the present invention,
9 is a graph showing external quantum efficiency (EQE) according to wavelength of a solar cell module including an organic solar cell of an embodiment and a comparative example according to an experimental example of the present invention,
10 is a graph showing a Nyquist plot of a solar cell module including an organic solar cell of an Example and a Comparative Example according to an experimental example of the present invention,
11 is an image showing a driving experiment result of an organic light emitting device of a comparative example according to an experimental example of the present invention,
12 is an image showing a driving experiment result of an organic light emitting device according to an exemplary embodiment of the present invention,
13 is a graph showing energy conversion efficiency according to driving time of an organic solar cell of an embodiment and a comparative example according to an experimental example of the present invention,
14 is an image showing the mechanical flexibility test results of ZnO and m-PEIE thin films according to an experimental example of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by an expert skilled in the art to which the present invention belongs. In general, the nomenclature used in this specification is well known and commonly used in the art.

In one aspect of the present invention

At least one polymer electron transport material selected from the group consisting of polyethyleneimine (Poly(ethyleneimine), PEI) and polyethyleneimine ethoxylated (Poly(ethyleneimine)-ethoxylated, PEIE); And

fatty acid;

An electron transport material for an optoelectronic device comprising a is provided.

Hereinafter, an electron transport material for an optoelectronic device provided in one aspect of the present invention will be described in detail for each configuration.

First, the electron transport material for a photoelectric device provided in one aspect of the present invention includes a polymer electron transport material.

The polymeric electron transport material may be polyethyleneimine (Poly (ethyleneimine), PEI), polyethyleneimine ethoxylated (Poly (ethyleneimine)-ethoxylated, PEIE), or a mixture thereof.

For example, polyethyleneimine ethoxylated may have a structure as shown in Formula 1 below.

The weight average molecular weight (M _w ) of the polymer electron transport material may be 1,000 to 1,000,000. When the molecular weight exceeds 1,000,000, there is a problem that the viscosity is too high and modification by fatty acids may be difficult.

Next, the electron transport material for a photoelectric device provided in one aspect of the present invention includes a fatty acid.

The fatty acid may have 4 to 28 carbon atoms, preferably 8 to 26 carbon atoms.

The fatty acid may be a saturated fatty acid or an unsaturated fatty acid.

In one embodiment, the fatty acid may be stearic acid or linoleic acid.

Stearic acid and linoleic acid may each have the same structure as in Chemical Formulas 2 and 3 below.

In the electron transport material for a photoelectric device provided in an aspect of the present invention, the polymeric electron transport material and the fatty acid may be included in a weight ratio of 1:1 to 1:50. Preferably, it may be 1:2 to 1:30, more preferably 1:4 to 1:20.

When the weight ratio is less than 1:1, there is a problem in that the fatty acid is insufficient and the polymer electron transport material may not be sufficiently modified.

It is preferable in that the performance as an electron transport material is the most excellent in the above range.

The polymer electron transport material may be in a state modified with the fatty acid, and the polymer electron transport material and the fatty acid may be bonded in various forms such as ionic bonds, hydrogen bonds, and van der Waals bonds, and are not limited to a specific bond form. Does not.

As an effect of this modification, it is possible to obtain an effect of improving photoelectric efficiency despite the addition of a non-conductor. This effect may be due to improved stability due to hydrophobic surface of the polymer electron transport material, or may be due to amine doping.

In the electron transport material for a photoelectric device provided in an aspect of the present invention, the photoelectric device may be an organic light emitting device or an organic solar cell.

Such an electron transport material may be included in an electron transport layer of an organic light emitting device or an electron transport layer of an organic solar cell.

The electron transport material for an optoelectronic device provided in an aspect of the present invention may be suitable for use in a flexible device because it has superior mechanical deformation properties compared to ZnO.

Hereinafter, a method of manufacturing an electron transport material for an optoelectronic device provided in one aspect of the present invention will be briefly described.

The polymer electron transport material and the fatty acid have been described above and are not described in duplicate.

The polymer electron transport material may be substituted with a fatty acid as shown in FIG. 2.

More specifically, preparing a solution containing a polymer; And adding a solution containing fatty acids to the solution containing the polymer.

In another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And

A photoelectric conversion layer positioned between the first electrode and the second electrode;

An optoelectronic device comprising a is provided.

The photoelectric device may be an organic light emitting device or an organic solar cell.

When the photoelectric device is an organic light emitting device, the photoelectric conversion layer may be an emission layer.

When the photoelectric device is an organic solar cell, the photoelectric conversion layer may be a photoactive layer.

This will be described in more detail below.

In another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And

A light emitting layer positioned between the first electrode and the second electrode;

An organic light-emitting device comprising a is provided.

The organic light-emitting device may be a general type of organic light-emitting device used in the art, except that the organic light-emitting device includes the electron transport material.

Hereinafter, an organic light-emitting device provided in another aspect of the present invention will be described in detail for each configuration.

First, the organic light emitting device provided in another aspect of the present invention may include a first electrode, a second electrode, an electron transport layer, and an emission layer.

In an embodiment, a hole transport layer may be further included.

In an embodiment, as shown on the left side of FIG. 1, a first electrode, a hole transport layer, an emission layer, an electron transport layer, and a second electrode may be stacked in order.

The first electrode may serve to inject holes into the hole transport layer.

The material constituting the first electrode is not particularly limited, and conventional materials known in the art may be used. Non-limiting examples thereof include metals such as vanadium, chromium, copper, zinc, and gold; Alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO:Al and SnO _{2 :Sb;} Conductive polymers such as polythiophene, poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline; And carbon black.

A method of manufacturing the first electrode is not particularly limited, and may be manufactured according to a conventional method known in the art. For example, a method of coating an anode material on a substrate made of a silicon wafer, quartz, glass plate, metal plate, or plastic film may be mentioned, or a sputtering method or a vapor deposition method may be used.

The hole transport layer serves to move holes injected from the first electrode to the emission layer.

Such a hole transport layer may further include a hole injection layer.

The material constituting the hole injection layer and the hole transport layer is not particularly limited as long as it is a material having a low hole injection barrier and high hole mobility, and a hole injection material/hole transport material used in the art may be used without limitation.

As the hole injection material, a hole injection material known in the art may be used without limitation. Non-limiting examples of usable hole injection materials include phthalocyanine compounds such as copper phthalocyanine; DNTPD (N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), mMTDATA(4,4',4 "-tris(3-methylphenylphenylamino) triphenylamine), TDATA(4,4'4"-Tris(N,Ndiphenylamino)triphenylamine), 2TNATA(4,4',4"-tris(N,-(2-naphthyl)- N-phenylamino}-triphenylamine), PEDOT/PSS(Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate)), PANI/DBSA(Polyaniline/Dodecylbenzenesulfonic acid), PANI/CSA(Polyaniline/Camphor sulfonic acid), PANI There are /PSS((Polyaniline)/Poly(4-styrenesulfonate)), etc. These can be used alone or in combination of two or more.

In addition, as the hole transport material, a hole transport material known in the art may be used without limitation. Non-limiting examples of usable hole transport materials include carbazole derivatives such as phenylcarbazole and polyvinylcarbazole, fluorene derivatives, TPD(N,N'-bis(3-methylphenyl)-N, Triphenylamine derivatives such as N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), TCTA(4,4',4"-tris(Ncarbazolyl)triphenylamine), NPB(N,N '-di(1-naphthyl)-N,N'-diphenylbenzidine), TAPC(4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), etc. These can be used alone, or Alternatively, two or more types can be mixed.

The hole transport layer may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

The light-emitting layer is a layer in which holes and electrons meet to form excitons, and the color of light emitted by the light-emitting device may vary according to a material constituting the light-emitting layer.

The emission layer may include a host, and may further include a dopant.

The host included in the light emitting layer of the present invention is not particularly limited as long as it is known in the art, and non-limiting examples thereof include an alkali metal complex; Alkaline earth metal complexes; Or condensed aromatic ring derivatives.

More specifically, as the host material, aluminum complexes, beryllium complexes, anthracene derivatives, pyrene derivatives, triphenylene derivatives, carbazole derivatives, dibenzofuran derivatives, dibenzothiones that can increase the luminous efficiency and lifespan of the light emitting device. It is preferred to use an offene derivative, or a combination of one or more thereof.

In addition, the dopant included in the light emitting layer of the present invention is not particularly limited as long as it is known in the art, and non-limiting examples thereof include anthracene derivatives, pyrene derivatives, arylamine derivatives, iridium (Ir) or platinum (Pt). The metal complex compound etc. which are mentioned are mentioned.

Meanwhile, the dopant may be classified into a red dopant, a green dopant, and a blue dopant, and red dopants, green dopants, and blue dopants commonly known in the art may be used without particular limitation.

Specifically, non-limiting examples of the red dopant include PtOEP (Pt(II) octaethylporphine: Pt(II) octaethylporphine), Ir(piq) ₃ (tris(2-phenylisoquinoline)iridium: tris(2-phenyliso). Quinoline) iridium), Btp2Ir(acac) (bis(2-(2'-benzothienyl)-pyridinato-N,C3')iridium(acetylacetonate): bis(2-(2'-benzothienyl)-pyridinato- N,C3') iridium (acetylacetonate)), and the like, which may be used alone or in combination of two or more.

In addition, non-limiting examples of the green dopant include Ir (ppy) ₃ (tris (2-phenylpyridine) iridium: tris (2-phenylpyridine) iridium), Ir (ppy) ₂ (acac) (Bis (2-phenylpyridine) (Acetylacetonato)iridium(III): bis(2-phenylpyridine)(acetylaceto) iridium(III)), Ir(mppy) ₃ (tris(2-(4-tolyl)phenylpiridine)iridium: tris(2-(4) -Tolyl)phenylpyridine)iridium), C545T (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano[ 6,7,8-ij]-quinolizin-11-one: 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7,-tetrahydro-1H, 5H,11H-[1]benzopyrano [6,7,8-ij]-quinolizin-11-one) and the like, which may be used alone or in combination of two or more.

In addition, non-limiting examples of the blue dopant include F ₂ Irpic (Bis[3,5-difluoro-2-(2-pyridyl)phenyl](picolinato)iridium(III): bis[3,5-difluoro- 2-(2-pyridyl)phenyl(picolinato) iridium(III)), (F ₂ ppy) ₂ Ir(tmd), Ir(dfppz) ₃ , DPVBi (4,4'-bis(2,2' -diphenylethen-1-yl)biphenyl: 4,4'-bis(2,2'-diphenylethen-1-yl)biphenyl), DPAVBi (4,4'-Bis[4-(diphenylamino)styryl] biphenyl: 4,4'-bis(4-diphenylaminostyryl)biphenyl), TBPe (2,5,8,11-tetra-tert-butyl perylene: 2,5,8,11-tetra-tert- Butyl perylene) and the like, which may be used alone or in combination of two or more.

The above-described light emitting layer may be a single layer or may be formed of a plurality of layers of two or more layers. Here, when the emission layer is a plurality of layers, the organic electroluminescent device may emit light of various colors. Specifically, the present invention can provide an organic electroluminescent device having a mixed color by providing a plurality of light-emitting layers made of different materials in series. In addition, when a plurality of emission layers are included, the driving voltage of the device is increased, while the current value in the organic EL device is constant, so that an organic EL device having improved luminous efficiency by the number of emission layers can be provided.

Such a light emitting layer may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

The electron transport layer serves to move electrons injected from the second electrode to the emission layer.

The electron transport layer includes at least one polymer electron transport material selected from the group consisting of polyethyleneimine (Poly(ethyleneimine), PEI) and polyethyleneimine ethoxylated (PEIE) and fatty acids. It may contain an electron transport material for the device.

Here, since the electron transport layer includes the electron transport material described above, a separate description thereof will be omitted.

When the electron transport material is included in the electron transport layer, the organic light emitting device may have improved efficiency, high stability, and excellent flexibility.

The electron transport layer may further include an electron injection layer. In the electron injection layer, an electron injection material having easy electron injection and high electron mobility may be used without limitation. Non-limiting examples of the electron injection material that can be used include the bipolar compound, anthracene derivative, heteroaromatic compound, alkali metal complex compound, and the like. Specifically, LiF, Li2O, BaO, NaCl, CsF; Lanthanum group metals such as Yb and the like; Or there is a metal halide such as RbCl, RbI, and the like, which may be used alone or in combination of two or more.

The electron transport layer may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

The second electrode serves to inject electrons into the electron transport layer.

The material constituting the second electrode is not particularly limited, and conventional materials known in the art may be used. Non-limiting examples thereof include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead; Alloys thereof; And multilayered materials such as LiF/Al and LiO _{2 /Al.} Preferably, it may be silver (Ag), aluminum (Al), magnesium (Mg), or an alloy thereof.

The method of manufacturing the negative electrode is not particularly limited, and, like the above-described first electrode, may be manufactured through a conventional method known in the art. For example, there are sputtering method and vapor deposition method.

In another aspect of the present invention

A first electrode;

A second electrode;

An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And

A photoactive layer positioned between the first electrode and the second electrode;

An organic solar cell comprising a is provided.

The organic solar cell may be a general type of organic solar cell used in the art except that it includes the electron transport material.

Hereinafter, an organic solar cell provided in another aspect of the present invention will be described in detail for each configuration.

First, an organic solar cell provided in another aspect of the present invention may include a first electrode, a second electrode, an electron transport layer, and a photoactive layer.

In an embodiment, a hole transport layer may be further included.

In an embodiment, as shown on the right side of FIG. 1, a first electrode, an electron transport layer, a photoactive layer, a hole transport layer, and a second electrode may be stacked in this order.

The first electrode is an electrode that provides electrons to the device, and may be a transparent conductive oxide layer or a metal electrode. When the electrode of the present specification is a transparent conductive oxide layer, the electrode is PET (polyethylene terephthalate), PEN (polyethylene naphthelate), PP (polyperopylene), PI (polyimide), PC (polycarbornate), PS ( Polystylene), POM (polyoxyethlene), AS resin (acrylonitrile styrene copolymer), ABS resin (acrylonitrile butadiene styrene copolymer), TAC (triacetyl cellulose), PAR (polyarylate) Those doped with the material may be used. Specifically, ITO (indium tin oxide), fluorine doped tin oxide (FTO), aluminum doped zink oxide (AZO), IZO (indium zink oxide), ZnO-Ga _{It may be 2} O ₃ , ZnO-Al ₂ O ₃ and ATO (antimony tin oxide), and more specifically ITO.

The electron transport layer is a layer added for high efficiency of the device by moving electrons generated in the photoactive layer to the first electrode.

The electron transport layer includes at least one polymer electron transport material selected from the group consisting of polyethyleneimine (Poly(ethyleneimine), PEI) and polyethyleneimine ethoxylated (PEIE) and fatty acids. It may contain an electron transport material for the device.

Here, since the electron transport layer includes the electron transport material described above, a separate description thereof will be omitted.

When the electron transport material is included in the electron transport layer, the organic solar cell may have improved efficiency, high stability, and excellent flexibility.

In addition, there is an advantage in that the output decrease is small even at a relatively low light amount.

The photoactive layer includes an organic material and generates electricity by photovoltaic of the organic material.

Organic materials that can be used for the photoactive layer are electron donor materials such as poly(3-hexylthiophene) (P3HT), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4') ,7'-di-2-thienyl-2',1',3'-benzothiadiazole)]), PSBTBT(Poly[2,6-(4,4'-bis(2-ethylhexyl)dithieno[3,2- b:2',3'-d]silole)-alt-4,7(2,1,3-benzothiadiazole)]), PTB7(Poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1 ,2-b:4,5-b']dithiophene-2,6-diyl-alt3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} ), as the electron acceptor material, organic polymer materials and derivatives thereof conventionally used in the photoactive layer, such as PCBMC60 (Phenyl-C61-butyric acid methyl ester), ICBA (Indene-C60 bis-adduct, etc.) can be used without limitation. .

The hole transport layer is a layer that helps to move holes generated in the photoactive layer to an anode, and is formed between the photoactive layer and the second electrode. For the hole transport layer, one or more of PEODT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate)), GO (graphene oxide), WO _x (tungsten oxide), MoOx (molybdate oxide) is selected, and the solution process It can be manufactured with.

The second electrode is an electrode that provides holes to the device, and may be formed through a solution process, such as screen printing, of a metal paste or a colloidal metal ink material in a predetermined liquid. Here, the metal paste may be any one of materials such as silver paste, aluminum paste, gold paste, copper paste, or alloyed form. In addition, the metallic ink material is at least one of silver (Ag) ink, aluminum (Al) ink, gold (Au) ink, calcium (Ca) ink, magnesium (Mg) ink, lithium (Li) ink, and cesium (Cs) ink. It can be either. The metallic substance contained in the metallic ink substance is in an ionized state inside the solution.

Hereinafter, the present invention will be described in detail through manufacturing examples and examples. However, the following Preparation Examples and Examples are for illustrative purposes only, and the contents of the present invention are not limited by the following Examples.

<Production Example 1> Preparation 1 of m-PEIE (S-PEIE)

First, a PEIE solution was prepared by adding 10 mL of ethanol to 20 mg of a stock solution of polyethyleneimine ethoxylated (PEIE). The PEIE stock solution was 80% ethoxylated solution (35-40wt% H ₂ O).

Thereafter, 500 μL of an RCOOH solution obtained by diluting stearic acid with ethanol is added to the finished PEIE solution.

With reference to FIG. 2, it can be understood.

<Production Example 2> Preparation 2 of m-PEIE (L-PEIE)

It was prepared in the same manner as in Preparation Example 1, but was prepared by adding 500 μL of an RCOOH solution obtained by diluting linoleic acid with ethanol to the finished PEIE solution.

<Example 1> Fabrication of an organic light emitting device

1, an organic light emitting device including the m-PEIE of Preparation Example 1 and Preparation Example 2 in the electron transport layer was manufactured, respectively.

The organic light emitting device was manufactured by a solution process on pre-structured indium tin oxide (ITO)-coated glass. In order to form a hole transport layer (HTL), PEDO:PSS (AI4083, Heraeus) was diluted with isopropyl alcohol in a volume ratio of 1:5, and this solution was prepared on an ITO-coated glass phase at 3000 rpm for 30 seconds in atmospheric air. After rotating at, it was annealed at 120°C.

In order to form a light emitting layer, a light emitting super yellow (PDY-132, Merck) solution of toluene (5 mg/mL) was spin-coated at 1500 rpm for 30 seconds and then annealed at 100° C. for 5 minutes in a nitrogen glove box.

Subsequently, m-PEIE of Preparation Example 1 and Preparation Example 2 was spin-coated at 5000 rpm for 40 seconds on the light emitting layer (EML) as an electron transport layer (ETL).

Finally, LiF (1 nm) and Al (70 nm) were sequentially thermally evaporated on the ETL. The active area of the device was about 6 mm ² .

The specific manufacturing process of the organic light emitting device is shown in detail in Table 1 below.

Glass / ITO Plasma treatment 15 min in air HTL PEDOT:PSS (AI4083)
: IPA = 1:5 3000 rpm
/ 30s 120°C
/ 10 min EML Super yellow
(PDY-132, merck)
(5mg/mL in Toluene) 1500 rpm
/ 30s 100°C
/ 5 min in glove box (N ₂ ) ETL ZnO NPs 4000 rpm
/ 30s 100°C
/ 10 min m-PEIE 5000 rpm
/ 30s LiF (1 nm)
/Al (100 nm) Thermal evaporation

<Example 2> Fabrication of an organic solar cell

1, an organic solar cell including the m-PEIE in an electron transport layer is manufactured.

UV ozone treatment was performed on the ITO glass substrate for 15 minutes, and the modified PEIE (m-PEIE) of Preparation Example 1 and Preparation Example 2 was spin-coated (2000 rpm, 40sec) thereon to form a thin film, which was at 100°C. An electron transport layer was formed by heat treatment for 10 minutes.

A PTB7; PCBM layer having a thickness of 70 nm to 150 nm was formed as a photoactive layer, and dried at room temperature for 1 hour. Thereafter, MoO _x (5-10 nm thick) and Ag (5-100 nm thick) thin films were formed through thermal evaporation, respectively.

The unit cell area was 0.38 cm ² .

<Comparative Example 1>

A light emitting device was manufactured in the same manner as in Example 1, but PEIE not substituted with a fatty acid was included in the electron transport layer.

<Comparative Example 2>

A solar cell was manufactured in the same manner as in Example 2, but PEIE not substituted with a fatty acid was included in the electron transport layer.

<Experimental Example 1> Evaluation of the performance of an organic light-emitting device

Among the organic light-emitting devices of Example 1, the performance of the organic light-emitting device using the m-PEIE of Preparation Example 2 was evaluated and shown in Table 2 and FIGS. 3 and 4 below. At this time, the concentration of fatty acids in the RCOOH solution used in manufacturing the organic light emitting device is 100 g/L.

Device Luminance [cd/m ² ] Current efficiency [cd/A] Power efficiency [lm/W] ZnO NPs 25063 11.44 9.28 m-PEIE (LA) 25116 16.03 (x1.4) 13.76 (x1.48)

As can be seen in Table 2 and FIGS. 3 and 4, it can be seen that luminance, current efficiency, and power efficiency are all improved in the case of using m-PEIE as in Example 1 compared to the case of using ZnO. In particular, it can be seen that the current efficiency is improved by 1.4 times and the power efficiency is improved by 1.48 times.

In addition, for the organic light emitting device of Example 1 and Comparative Example 1, the performance was measured and compared, and the results are shown in Table 3 below. At this time, m-PEIE of Preparation Example 1 was used, and the concentration of fatty acid in the RCOOH solution used in the manufacturing process was 100 g/L.

OLED Luminance [cd/m ² ] Current efficiency [cd/A] Power efficiency [lm/W] R-OLED PEIE 24,950 10.89 10.1 m-PEIE 25,253 15.18 14.42 F-OLED PEIE 22985 6.8 5.54 m-PEIE 22748 9.68 9.88

Here, R-OLED refers to an organic light-emitting device made on a glass substrate, and F-OLED refers to an organic light-emitting device made on a flexible substrate.

As can be seen in Table 3, compared to the case of using PEIE as in Comparative Example 1, when using the PEIE (m-PEIE) modified with fatty acid as in Example 1, the current efficiency is about 1.3 to 1.5 times, respectively. It can be seen that the improvement is improved, and the power efficiency is improved by about 1.4 to 1.8 times.

<Experimental Example 2> Performance evaluation of an organic light emitting device according to the concentration of fatty acids

For the organic solar cell using the m-PEIE of Preparation Example 1 of Example 2, the performance of the organic solar cell according to the concentration of stearic acid in the RCOOH solution in which stearic acid was diluted with ethanol was evaluated. It is shown in 4.

Device ETL thickness PCE best (%) F.F Voc (V) Jsc (mA/cm ² ) Rs Rsh PEIE ~ 5 nm 8.65 0.62 0.78 18.09 36.44 5000 PEIE +60 RCOOH ~ 5 nm 9.7 0.67 0.78 18.49 28.36 20000 PEIE+ 100 RCOOH ~ 5 nm 9.87 0.68 0.78 18.72 28.46 5000 PEIE+140 RCOOH ~ 5 nm 9.75 0.67 0.78 18.71 30.3 4000 PEIE+180 RCOOH ~ 5 nm 9.72 0.68 0.78 18.43 27.26 20000 PEIE+220 RCOOH ~ 5 nm 9.62 0.67 0.78 18.46 33.1 5000

In Table 4, the numbers in front of RCOOH (60, 100, 140, 180, 220) represent the concentration of fatty acids in the solution in g/L units. For example, 60 RCOOH means that 60 g/L of fatty acids are contained in RCOOH.

As can be seen in Table 4, compared to PEIE not modified with fatty acid (Comparative Example 2), when modified with fatty acid, it can be seen that the performance of the organic solar cell is remarkably improved.

<Experimental Example 3> Performance evaluation of organic solar cell

The performance of the organic solar cells of Comparative Example 2 and Example 2 was measured and shown in Table 5 and FIGS. 5 to 7 below. At this time, the concentration of fatty acids in the RCOOH solution used in the manufacturing process is 100 g/L.

The organic solar cell has ^{a size of 2.5 × 2.5 cm 2} and an active area of 0.38 cm ² .

ETL PEIE S-PEIE L-PEIE PCE (%) 7.61 8.3 8.41 FF 0.63 0.68 0.68 Voc (V) 0.76 0.76 0.76 Jsc (㎃/㎠) 15.88 15.97 16.05 Calculated Jsc (㎃/㎠) 15.54 15.66 15.73 Rs(Ω) 11.69 11.79 14.14 Capacitance(F) 10e ^-8 2.85 3.04 3.54 Rp(Ω) 121.97 103.0 77.58

In Table 5, S-PEIE refers to PEIE substituted with stearic acid, L-PEIE refers to PEIE substituted with linoleic acid, and Rp refers to charge transfer resistance, and Cp refers to capacitance.

It can be seen that all the measured values are improved compared to the case of using the unmodified PEIE for both S-PEIE and L-PEIE. In particular, it can be seen that the use of L-PEIE showed the best performance as a solar cell.

In addition, the performance values for R-OPV and F-OPV of the organic solar cells of Comparative Example 2 and Example 2 were measured and shown in Table 6 below. At this time, m-PEIE of Preparation Example 1 was used, and the concentration of fatty acid in the RCOOH solution used in the manufacturing process was 100 g/L.

OPV PCE Voc FF Jsc Rs [%] [V] [mA·cm ^-2 ] [Ωcm ² ] R-OPV PEIE 8.65 0.78 0.62 18.09 36.44 m-PEIE 9.87 0.78 0.68 18.72 28.46 F-OPV PEIE 7.55 0.76 0.64 15.53 18.55 (7.59±0.12) (0.76±0.01) (0.64±0.01) (15.65±0.40) m-PEIE 8.6 0.76 0.67 16.89 15.71 (8.39±0.05) (0.77±0.01) (0.65±0.01) (16.65±0.07)

Here, R-OPV means an organic solar cell made on a glass substrate, and F-OPV means an organic solar cell made on a flexible substrate (PEN).

Table 6 also supports that PEIE exhibits improved performance when modified with fatty acids.

<Experimental Example 4> Performance evaluation of organic solar cell module

The performance of the solar cell module including the organic solar cell of Comparative Example 2 and Example 2 was measured and shown in Table 6 and FIGS. 8 to 10 below. The concentration of fatty acids in the RCOOH solution used in the manufacturing process is 100 g/L.

The organic solar cell module has ^{a size of 5 × 7 cm 2} and an active area of 13.16 cm ² .

ETL PEIE S-PEIE L-PEIE PCE (%) 6.60 7.97 8.17 FF 0.64 0.63 0.66 Voc (V) 5.22 5.47 5.49 Jsc (㎃/㎠) 2.09 2.31 2.26 Calculated Jsc (㎃/㎠) 2.04 2.36 2.36 Rs(Ω) 18.71 19.40 19.97 Capacitance(F) 10e ^-8 1.97 2.16 2.14 Rp(Ω) 169.0 139.2 143.8

It can be seen that all the measured values are improved compared to the case of using the unmodified PEIE for both S-PEIE and L-PEIE. In particular, it can be seen that the L-PEIE showed the best performance as a solar cell module.

<Experimental Example 5> Evaluation of the stability of an organic light-emitting device

For the organic light emitting device of Example 1 and Comparative Example 1, stability was measured, and the results are shown in FIGS. 11 and 12.

The drawings on the left of FIGS. 11 and 12 show an image after 28 days in a 4 pixel test of 5 V. It can be seen from FIG. 12 that even if four are simultaneously driven, all driving is well performed in the case of Example 1. . On the other hand, in Comparative Example 1, it can be confirmed through FIG. 11 that the driving is not performed well.

In addition, the diagrams on the right side of FIGS. 11 and 12 show images after 30 days in a 1 pixel test of 5 V, showing a case of driving one by one after storage in the air. Even in this case, it can be seen that Example 1 works significantly better than Comparative Example 1 (FIGS. 11 and 12).

That is, as in Example 1, it can be seen that the stability of the organic light emitting device using m-PEIE is more excellent.

<Experimental Example 6> Stability evaluation of organic solar cell

For the organic solar cells of Example 2 and Comparative Example 2, stability was measured, and the results are shown in FIG. 13 below.

As can be seen from the graph of FIG. 13, it can be seen that the solar cell of Example 2 continues to have higher energy conversion efficiency compared to Comparative Example 2 even when time elapses.

That is, as in Example 2, it can be seen that the stability of the organic solar cell using m-PEIE is more excellent.

<Experimental Example 7> Evaluation of flexibility of m-PEIE

Mechanical flexibility was tested for the case where ZnO was formed on the ITO and the m-PEIE of Preparation Example 1 was formed on the ITO substrate.

Banding was performed for a total of 500 cycles.

As can be seen in FIG. 14, it can be seen that less cracks were formed in m-PEIE than in ZnO, and the flexibility of m-PEIE was more excellent.

<Experimental Example 8> Evaluation of output of organic solar cell at low light intensity

For the organic solar cell (m-PEIE) module of Example 2 and the organic solar cell module including an electron transport layer manufactured using various other electron transport materials, the amount of light was measured and shown in Table 8 below.

Light quantity (lux) m-PEIE ZnO ripple ZnO NPs PEIE-ZnO 200 0.11 0.05 0.04 0.04 500 0.36 0.21 0.1 0.14 750 0.57 0.28 0.16 0.22 1000 0.81 0.39 0.17 0.32 2000 1.72 0.9 0.52 0.95 1 sun 157.34 160.25 169.46 171.06

In Table 8, the unit of each value is mW.

As can be seen in Table 8, it can be seen that in the case of the organic solar cell using m-PEIE as in Example 2, the output decrease is significantly less than that of the case of using other materials even at low light intensity.

Claims (11)

At least one polymer electron transport material selected from the group consisting of polyethyleneimine (Poly(ethyleneimine), PEI) and polyethyleneimine ethoxylated (Poly(ethyleneimine)-ethoxylated, PEIE); And
fatty acid;
Electron transport material for an optoelectronic device comprising a.
The method of claim 1,
The fatty acid is an electron transport material for a photoelectric device, characterized in that 4 to 28 carbon atoms.
The method of claim 1,
The fatty acid is an electron transport material for a photoelectric device, characterized in that 8 to 26 carbon atoms.
The method of claim 1,
The fatty acid is an electron transport material for a photoelectric device, characterized in that the saturated fatty acid or unsaturated fatty acid.
The method of claim 1,
The electron transport material for an photoelectric device, characterized in that the polymeric electron transport material and the fatty acid are contained in a weight ratio of 1:1 to 1:50.
The method of claim 1,
The photoelectric device is an electron transport material for a photoelectric device, characterized in that the organic light emitting device or an organic solar cell.
A first electrode;
A second electrode;
An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And
A photoelectric conversion layer positioned between the first electrode and the second electrode;
Photoelectric device comprising a.
A first electrode;
A second electrode;
An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And
A light emitting layer positioned between the first electrode and the second electrode;
An organic light emitting device comprising a.
The method of claim 8,
The organic light emitting device further comprises a hole transport layer between the first electrode and the second electrode.
A first electrode;
A second electrode;
An electron transport layer comprising the electron transport material for an optoelectronic device of claim 1, positioned between the first electrode and the second electrode; And
A photoactive layer positioned between the first electrode and the second electrode;
Organic solar cell comprising a.
The method of claim 10,
The organic solar cell further comprises a hole transport layer between the first electrode and the second electrode.

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