KR20110134728A - Manufacturing method of high efficiency organic photovoltaic cells - Google Patents

Abstract

PURPOSE: A manufacturing method of high efficiency organic photovoltaic cells is provided to provide an organic solar cell having high efficiency by improving surface morphology and increasing short circuit current density, an open circuit voltage, and a fill factor. CONSTITUTION: In a manufacturing method of high efficiency organic photovoltaic cells, a first electrode(120) is formed on a substrate(110). A hole-transport layer(130) is formed on the first electrode. A photoelectric conversion layer(140) is formed on the hole-transport layer. An electron-transport layer(150) is formed on the photoelectric conversion layer. A second electrode(160) is formed on the electron-transport layer.

Description

High efficiency organic solar cell and its manufacturing method {Manufacturing method of high efficiency organic photovoltaic cells}

The present invention relates to a highly efficient organic solar cell and a method for manufacturing the same by improving the morphology of the electron transport layer, and more particularly, by adding a surfactant to a water-soluble polymer electron transport layer having an electrophilic function. The present invention relates to an organic solar cell having high efficiency and a method of manufacturing the same by increasing short circuit current density, open circuit voltage, and fill factor.

Solar cells are being reassessed from the viewpoint of preserving the global environment due to their non-pollution, and research is being actively conducted as a next-generation clean energy source.

The types of solar cells known to date include solar cells using monocrystalline or polycrystalline bulk silicon, thin film solar cells using amorphous, microcrystalline or polycrystalline silicon, compound semiconductor solar cells, fuel-sensitized solar cells, and organic polymer solar cells. Varies.

Solar cells using commercially available single crystal bulk silicon have not been actively utilized due to high manufacturing cost and installation cost. In order to solve such a cost problem, researches on thin film solar cells using organic materials are underway, and various attempts have been made to manufacture high efficiency solar cells.

Organic thin film solar cell technology converts solar energy into electrical energy using polymer or low molecular organic semiconductor. Its thin-film device, large-area device, and roll- It is a next-generation technology with both ultra-low cost and versatile mass production specifications such as flexible elements by a roll-to-roll method.

In general, an organic solar cell is composed of a junction structure of an electron donor and an electron acceptor material. When light is incident on the photoelectric conversion layer, electrons and hole pairs are excited in the electron donor, and electrons are electrons. By moving to the receptor, separation of electrons and holes occurs. Therefore, the carriers generated by the light generate power as they move to the external circuit through the phenomenon of electron-hole separation.

For the same reason as above, in recent years, interest in bulk heterojunction organic solar cells that can be applied to flexible substrates with low cost has been improved. US Patent Publication No. 2006-0011233 discloses poly-3-hexylthiophene (P3HT) as an electron donor and [6,6] -phenyl- C ₆₁ -butyl acid methyl ester as an electron acceptor ( Organic solar cells using a [6,6] -phenyl- C ₆₁ -butyric acid methyl ester (PCBM) and a photoelectric conversion layer introduced by spin coating have been disclosed, but their energy conversion efficiency is not high. There was.

In order to solve this problem, research is being conducted to increase energy conversion efficiency by inserting one or more layers such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer into an organic solar cell having a bulk heterojunction structure. Representatively, Korean Patent Publication No. 10-2007-0108040 introduces a G-PEDOT: PSS containing glycerol to the hole transport layer of the organic solar cell to manufacture an organic solar cell having a bulk heterojunction structure, but still has low energy conversion efficiency. In the KY Jen group, the open voltage was improved by using poly [9,9-bis (6 '-(diethanolamino) hexyl) -fluorene] (PFN-OH) having the structure of Chemical Formula 1 as an electron transporting layer. Due to the poor morphology of the thin film, no increase in energy conversion efficiency was observed.

[Formula 1]

poly [9,9-bis (6 '-(diethanolamino) hexyl) -fluorene] (PFN-OH)

Therefore, in order to commercialize an organic solar cell, it is necessary to develop a device showing higher energy conversion efficiency.

Accordingly, the present invention has been made to solve the above problems, the main object of the present invention is to improve the surface morphology (surface morphology) of the electron transport layer formed by a water-soluble polymer having an electrophilic functional group, short circuit current density The present invention provides an organic solar cell having high efficiency and a method of manufacturing the same by increasing a short circuit current density, an open circuit voltage, and a fill factor.

In order to achieve the above object, the present invention is an organic solar cell comprising a first electrode, a hole transport layer, a photoelectric change layer, an electron transport layer and a second electrode formed on a transparent substrate, a surfactant is added to the electron transport layer By providing a high efficiency organic solar cell with improved surface morphology of the electron transport layer.

In the present invention, the surfactant added to the electron transport layer is 2,4,7,9-tetramethyl-5-dekin-4,7-diol (2,4,7,9-tetramethyl-5-decyne-4, 7-diol), and the surfactant is 2-ethylhexanol, 2-butoxyhexanol, 2-butoxyethanol, dipropylene glycol, ethylene glycol ), n-propyl alcohol, isopropyl alcohol, isopropyl alcohol, propylene glycol dissolved in any one or more solvents selected from the group consisting of 0.1 to 3% by weight relative to the electron transport layer It is good to add.

The present invention also provides a method of manufacturing a high efficiency organic solar cell, wherein a surfactant is added to the electron transport layer to improve the surface morphology of the electron transport layer.

Specifically, the present invention comprises the steps of (1) dissolving a water-soluble polymer having an electrophilic functional group; (2) adding a surfactant to the polymer solution; And (3) filtering the solution to form a thin film. The method of preparing an electron transporting layer includes a poly [9,9-bis (6 ′-(d). Ethanolamino) hexyl) -fluorene] and the surfactant is 2,4,7,9-tetramethyl-5-dekin-4,7-diol (2,4,7,9-tetramethyl-5-decyne- 4,7-diol).

According to the present invention as described above, the present invention improves the adhesion between the photoelectric conversion layer and the electron transport layer by adding a surfactant to the electron transport layer introduced with a water-soluble polymer having an organic electrophilic functional group, and the microforms inside the electron transport layer ( It removes microfoams and improves surface morphology, resulting in high efficiency organic solar cells by increasing short circuit current density, open circuit voltage, and fill factor. It is possible to provide a battery.

In addition, the organic solar cell to which the electron transport layer of the present invention is applied has excellent energy conversion efficiency and can form a thin film by a relatively simple process such as inkjet printing, screen printing, and gravure printing. It can be produced at a low price.

1 is a structure of an organic solar cell according to the present invention.
2 is a graph showing current density-voltage (JV) characteristics of an organic solar cell according to Examples and Comparative Examples of the present invention.
3 is an IPCE graph of an organic solar cell according to Examples and Comparative Examples of the present invention.
4A is an AFM photograph of a photoactive layer according to an embodiment of the present invention (RMS 0.32 nm).
Figure 4b is an AFM image of the electron transport layer PFN-OH according to an embodiment of the present invention (RMS 0.556 nm).
4C is an AFM photograph of an electron transport layer added with a surfactant dissolved in isopropyl alcohol according to an embodiment of the present invention (RMS 0.276 nm).
4D is an AFM photograph of an electron transport layer added with a surfactant dissolved in ethylene glycol according to an embodiment of the present invention (RMS 0.156 nm).

Hereinafter, the present invention will be described in detail.

1 is a schematic structure of an organic solar cell manufactured according to a preferred embodiment of the present invention, as shown, the substrate 110, the first electrode 120, the hole transport layer 130, the photoelectric conversion layer from the bottom 140, the electron transport layer 150, and the second electrode 160 are stacked.

In the present invention, the substrate 110 used in the device fabrication is in addition to glass and quartz plate polyethylene terephthalate (PET), polyethylene naphthelate (PEN), polyperopylene (PP), polyimide (PI), polycarbornate (PC), PS (polystylene) ), POM (polyoxyethlene), AS resin (acrylonitrile styrene copolymer), ABS resin (acrylonitrile butadiene styrene copolymer) and may be made of a flexible and transparent material such as plastic, such as triacetyl cellulose (TAC).

The first electrode 120 of the present invention is coated with a transparent electrode material on one side of the substrate by using sputtering, E-Beam, thermal evaporation, spin coating, screen printing, inkjet printing, doctor blade or gravure printing, or in the form of a film. It is formed by coating with. The first electrode 120 is a part that functions as an anode, and any material having transparency and conductivity may be used as a material having a higher work function than the second electrode 160 described later. For example, indium tin oxide (ITO), gold, silver, fluorine doped tin oxide (FTO), aluminum doped zink oxide (AZO), indium zink oxide ), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O _3, antimony tin oxide (ATO), and the like, and preferably ITO is used.

The patterned ITO substrate is washed sequentially with a detergent, acetone and isopropanol (IPA), and then dried for 1 to 30 minutes at 100 to 150 ° C., preferably at 120 ° C. for 10 minutes on a heating plate to remove moisture, and the substrate is thoroughly cleaned. The surface of the substrate is modified to be hydrophilic.

Through the surface modification as described above, the bonding surface potential can be maintained at a level suitable for the surface potential of the hole injection layer, and when opened, the formation of the polymer thin film on the ITO substrate is facilitated and the quality of the thin film is improved. Pretreatment techniques for this are a) surface oxidation using parallel planar discharge, b) oxidation of the surface through ozone generated using UV ultraviolet light in a vacuum state, and c) oxygen radicals generated by plasma. There is a method to oxidize, etc., depending on the state of the substrate to select one of the above methods, whichever method is commonly used to prevent oxygen escape from the surface of the substrate and to minimize the residual of moisture and organic matter in order to achieve the substantial effect of the pretreatment You can expect

In an embodiment of the present invention, a method of oxidizing a surface through ozone generated by using UV was used. After ultrasonic cleaning, the patterned ITO substrate was baked on a hot plate, dried well, and then placed in a chamber. The UV lamp is activated to clean the ITO substrate patterned by ozone generated by oxygen gas reacting with UV light.

However, the surface modification method of the patterned ITO substrate in this invention does not need to be specifically limited, Any method may be used as long as it is a method of oxidizing a substrate.

The hole transport layer 130 is introduced into the pretreated first electrode 120 through spin coating or dip coating. In the present invention, poly (3,4-ethylenedioxythiophene) is used as the conductive polymer solution. It is preferable to use poly (4-styrenesulfonate) [PEDOT: PSS].

The photoelectric conversion layer 140 of the present invention is poly [N-9'-heptadecanyl-2,7-carbazole-al-5,5- (4 ', 7'-di-2-thienyl-2 Low band gap polymers such as ', 1', 3'-benzothiadiazole)] [PCDTBT] or CT type polymers and derivatives thereof are used as electron donors, and [6,6] -phenyl- C ₆₁ Butyric acid methyl ester (PCBM (C ₆₀ )) and [6,6] -phenyl- C ₇₁ -butyl acid methyl ester (PC ₇₁ BM) as electron acceptors, with a ratio of 1: 2 to 1: 6, Preferably, a photoelectric conversion material mixed in a weight ratio of 1: 3 to 1: 5 may be used.

Such photoelectric conversion materials are dissolved in an organic solvent. Preferably, a solution obtained by dissolving two or more boiling points in an organic solvent having different boiling points in a thickness of 10 to 150 nm, preferably 60 to 120 nm by spin coating or the like is used. Introduce. In this case, the photoelectric conversion layer may be applied to methods such as dip coating, screen printing, spray coating, doctor blade, brush painting, and the like.

In addition, the electron acceptor may include other fullerene derivatives such as C ₇₀ , C ₇₆ , C ₇₈ , C ₈₀ , C ₈₂ , C ₈₄ , including PCBM (C ₆₀ ), and the coated thin film is 80 to 160 ° C. Preferably, the annealed at 90 to 140 ℃ to improve the crystallinity of the conductive polymer.

The electron transport layer 150 of the present invention is prepared by adding a surfactant to improve the morphology of the electron transport layer.

In this case, the electron transport layer may be prepared by dissolving a water-soluble polymer having an electrophilic function in water, ethanol or a mixed solvent thereof, adding a surfactant to the polymer solution and then filtering to form a thin film. have.

In the present invention, as the water-soluble polymer having an electrophilic functional group, poly [9,9-bis (6'- diethanolamino) hexyl) -fluorene] is preferable, and the surfactant is 2,4,7,9. Preference is given to -tetramethyl-5-dekin-4,7-diol.

More preferably, the surfactant is 2-ethylhexanol, 2-butoxyethanol, dipropylene glycol, ethylene glycol, n-propyl 50-75% by weight in one or more solvents selected from the group consisting of alcohol (n-propyl alcohol), isopropyl alcohol, propylene glycol (propylene glycol), the water-soluble polymer is water, ethanol or It is preferable to add 1 to 3% by weight to a solution dissolved at 0.1 to 1% by weight of these mixtures, and then mix and heat-treat by 2 to 20 nm coating by a method such as spin coating.

Most preferably, 2,4,7, in a solution of poly [9,9-bis (6 '-(diethanolamino) hexyl) -fluorene] [PFN-OH] dissolved in 0.1 to 0.5% by weight of ethanol 9-tetramethyl-5-dekin-4,7-diol was added by mixing 1 to 3% by weight of a solution of 50% by weight dissolved in ethylene glycol, and then coated with a thickness of 5 to 15nm by spin coating to 70 to 90 Heat treatment at 10 ° C. for 30 minutes is preferred.

In addition, the electron transport layer may be applied to methods such as dip coating, screen printing, inkjet printing, gravure printing, spray coating, doctor blade, brush painting, etc., but the present invention is not limited thereto.

The electron transport layer 150 to which the surfactant is added has an improved surface morphology, so that short circuit current density, open circuit voltage, and fill factor increase energy conversion. Good for efficiency

The second electrode 160 of the present invention is deposited inside the thermal evaporator exhibiting a vacuum degree of 5 kPa 10 ^-7 torr or less in the state in which the electron transport layer 150 is introduced. The electrode materials usable here include lithium fluoride / aluminum, lithium fluoride / calcium / aluminum, calcium / aluminum, barium fluoride / aluminum, barium fluoride / barium / aluminum, barium / aluminum, aluminum, gold, silver, magnesium: silver, Or lithium: aluminum, and it is preferable to use an electrode made of a barium fluoride / barium / aluminum structure.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

Example 1. Patterned ITO Substrate Cleaning

To clean the surface of the patterned ITO glass (Surface Resistance: ~ 15 Ω / sq ² , Samsung Corning, Korea) substrate, 20 minutes each using a cleaning agent (Alconox, Aldtrich, USA), acetone, and isopropanol (IPA) sequentially After performing ultrasonic cleaning, water was completely blown with nitrogen and dried at 120 ° C. for 10 minutes on a heating plate to completely remove moisture.

Once the cleaning of the patterned ITO substrate was completed, the surface was hydrophilically modified for 10 minutes in a UVO cleaner (UVO cleaner, Ahtech LTS, Korea).

Example 2 Preparation of Electron Transport Layer (1)

In order to improve the morphology of the electron transport layer, a solution in which a surfactant, 2,4,7,9-tetramethyl-5-dekin-4,7-diol, is dissolved in isopropyl alcohol by 50% by weight (Sufynol 104 PA, Air Products, USA) was added to the solution of 0.2% by weight of poly [9,9-bis (6 '-(diethanolamino) hexyl) -fluorene] [PFN-OH] in ethanol, and stirred for 24 hours. After introducing into a thickness of 10 nm by spin coating or the like, and then heat-treated for 20 minutes at 80 ℃.

Example 3 Preparation of Electron Transport Layer (2)

A 50% by weight solution of 2,4,7,9-tetramethyl-5-decyne-4,7-diol in ethylene glycol was used to improve the morphology of the electron transport layer (Sufynol 104 E, Air Products, USA ) Was added to a solution of 0.2% by weight of poly [9,9-bis (6 '-(diethanolamino) hexyl) -fluorene] [PFN-OH] in ethanol, and then stirred for 24 hours. After introducing into a thickness of 10 nm by spin coating or the like, and then heat-treated at 80 ℃ 20 minutes.

Example 4 Fabrication of Organic Solar Cell (1)

Poly (3,4-ethylenedioxythiophene): poly (4-styrenesulfonate) [PEDOT: PSS] was spin-coated 40 nm thick on the patterned ITO prepared in Example 1 above, followed by 120 on a hotplate. Heat treatment was performed at 20 ° C. for 20 minutes to remove residual solvent to complete the buffer layer.

Poly [N-9'-heptadecanyl-2,7-carbazole-al-5,5- (4 ', 7'-di-2-thienyl-2', 1 ', 3'-benzothiadia Sol)] [PCDTBT] and PCBM 70 were dissolved in an ortho-dichlorobenzene solvent at a weight ratio of 1: 4 by dissolving the photoelectric conversion layer material at a concentration of 0.5% by weight, and spin the ITO substrate into which the buffer layer was introduced. After coating and heat treatment at 120 ℃ for 10 minutes to introduce a 100 nm thick photoelectric conversion layer.

In the electron transport layer, a solution obtained by dissolving poly [9,9-bis (6 '-(dieethanolamino) hexyl) -fluorene] [PFN-OH] in 0.2% by weight in ethanol was spin-coated to a thickness of 10 nm, and then 80 Heat-treated for 20 minutes at ° C.

Subsequently, barium fluoride (BaF ₂ ) was 2 nm at a rate of 0.1 mW / s, and barium (Ba) was 2 nm at a rate of 0.2 mW / s, and inside the thermal evaporator having a vacuum degree of 5 × 10 ⁻⁷ torr or less. An organic solar cell was prepared by depositing 100 nm of Al) at a rate of 5 mA / s.

The device thus manufactured was introduced with a moisture and oxygen absorbent to the inner surface of the encapsulating glass in order to prevent decomposition by moisture and oxygen, and then sealed using an ultraviolet curing agent.

Example 5 Fabrication of Organic Solar Cell (2)

An organic solar cell was manufactured by the same method and condition as in Example 4, except that the electron transport layer was manufactured by the method of Example 2.

Example 6 Fabrication of Organic Solar Cell (3)

An organic solar cell was manufactured by the same method and condition as in Example 4, but the electron transport layer was manufactured by the method of Example 3.

Comparative Example 1. Fabrication of Organic Solar Cell (4)

An organic solar cell was manufactured in the same manner and in the same manner as in Example 4, but without introducing an electron transport layer.

Comparative Example 2. Fabrication of Organic Solar Cell (5)

An organic solar cell was manufactured by the same method and condition as in Comparative Example 1, except that BaF ₂ and Ba were not introduced.

Experimental Example 1. Evaluation of Characteristics of Organic Solar Cell

In order to measure the electro-optical characteristics of the organic solar cells manufactured in Examples 4 to 6 and Comparative Examples 1 and 2, standard conditions (Air) were used using a Keithley 2400 source meter and an Oriel 150W solar simulator. Mass 1.5 Global, 100 mA / cm 2, 25 ° C.), current-voltage density was measured.

Optical short-circuit current density (Jsc), photo-opening voltage (Voc), fill factor (FF) and energy conversion efficiency of the organic solar cells are shown in Table 1 below.

At this time, the Fill Factor (FF) is the voltage value (Vmax) ㅧ current density (Jmax) / (Voc ㅧ Jsc) at the maximum power point, and the energy conversion efficiency is FF ㅧ (JscJ Voc) / Pin, Pin = 100 [㎽ / Cm 2].

Optical short circuit current density
Jsc (㎃ / ㎠) Photo-opening voltage
Voc (V) Fill Factor
(%) Energy conversion efficiency
(%) Example 4 8.6 0.8990 42.1 3.2 Example 5 8.8 0.9394 43.7 3.6 Example 6 9.9 0.9596 44.5 4.2 Comparative Example 1 8.0 0.9394 39.7 3.0 Comparative Example 2 8.7 0.8182 35.4 2.5

In addition, Figure 2 is a graph of the current density-voltage (JV) characteristics of the organic solar cells, Figure 3 is an incident photon-to-current conversion efficiency (IPCE) graph, Figure 4 is manufactured in the above An AFM picture of an electron transport layer.

As can be seen from Table 1 and FIGS. 2 and 3, the photoelectric conversion efficiency in Comparative Example is 4.2% in Example 6, up to 68%, compared with 3.0% in Comparative Example 1 and 2.5% in Comparative Example 2, respectively. Showed an increase.

In the case of Comparative Example 2 in which only the aluminum electrode was introduced into the photoelectric conversion layer, the lowest photo-opening voltage and fill factor were shown in the absence of the electron injection layer and the electron transport layer, resulting in a low energy conversion efficiency of 2.5%. However, in Comparative Example 1 in which Ba, an electron injection layer, and BaF ₂ , an electron transport layer were introduced, 3.0% of the energy conversion efficiency was increased as the photo-opening voltage and the fill factor were increased.

In Example 4 in which PFN-OH was introduced as the electron transporting layer, the optical short-circuit current density and the fill factor were increased more than those in Comparative Example 1, showing an increased energy conversion efficiency of 3.2%. The introduction of the PFN-OH layer was expected to increase the energy conversion efficiency due to the increase of the electron transport capacity, but only a slight increase was observed due to the decrease in the photo-opening voltage. The reason can be interpreted through observation of the morphology of FIGS. 4A and 4B. The root mean square (RMS) of the PCDTBT thin film, which is a photoactive layer, is 0.32 nm, but the RMS of the PCDTBT / PFN-OH thin film has been increased to 0.556 nm. Typically, an increase in surface roughness shows an increase in short-circuit current density due to an increase in cathode and contact area, but causes a decrease in photo-opening voltage and fill factor. Therefore, Example 4 showed an increase in short-circuit current density by PFN-OH, an electrophilic functional group, but did not show a significantly improved energy conversion efficiency due to poor surface roughness.

Thus, the surface roughness was improved by introducing a surfactant in which 2,4,7,9-tetramethyl-5-dekin-4,7-diol was dissolved in isopropyl alcohol to PFN-OH. As shown in FIG. 4C, the RMS in Example 5 was lower than the RMS of PCDTBT at 0.276 nm, and the optical short-circuit current density, photo-opening voltage, and fill factor were all increased to show an energy conversion efficiency of 3.6%.

Example 6 in which 2,4,7,9-tetramethyl-5-dekin-4,7-diol dissolved in ethylene glycol was introduced into PFN-OH, as shown in FIG. 4D, the RMS was 0.156 nm. I could see that it was very good. The optical short-circuit current density is 9.9mA / cm ² , the photo-opening voltage is 0.9596V, the fill factor is 44.5% and the energy conversion efficiency is 4.2%, which is 68% higher than that of Comparative Example 2 without the electron transport layer and electron injection layer. Showed.

As described above, specific portions of the contents of the present invention have been described in detail, and for those skilled in the art, these specific techniques are merely preferred embodiments, and the scope of the present invention is not limited thereto. Will be obvious. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (10)

In the solar cell comprising a first electrode, a hole transport layer, a photoelectric change layer, an electron transport layer and a second electrode formed on a transparent substrate,
A high efficiency organic solar cell, wherein the surface morphology of the electron transport layer is improved by adding a surfactant to the electron transport layer.
The method of claim 1,
The surfactant is 2,4,7,9-tetramethyl-5-dekin-4,7-diol
High efficiency organic solar cell, characterized in that (2,4,7,9-tetramethyl-5-decyne-4,7-diol).
The method of claim 2,
The surfactant is 2-ethylhexanol, 2-butoxyethanol, 2-butoxyethanol, dipropylene glycol, ethylene glycol, n-propyl alcohol High efficiency organic solar cell, characterized in that dissolved in any one or more solvents selected from the group consisting of alcohol, isopropyl alcohol, propylene glycol is added in an amount of 0.1 to 3% by weight based on the electron transport layer .
A method of manufacturing a high efficiency organic solar cell, wherein a surface morphology of the electron transport layer is improved by adding a surfactant to the electron transport layer.
The method of claim 4, wherein
The surfactant is 2,4,7,9-tetramethyl-5-dekin-4,7-diol
(2,4,7,9-tetramethyl-5-decyne-4,7-diol) The manufacturing method of the high efficiency organic solar cell characterized by the above-mentioned.
The method of claim 4, wherein
The surfactant is 2-ethylhexanol, 2-butoxyethanol, 2-butoxyethanol, dipropylene glycol, ethylene glycol, n-propyl alcohol (n-propyl alcohol). High efficiency organic solar cell, characterized in that dissolved in any one or more solvents selected from the group consisting of alcohol, isopropyl alcohol, propylene glycol is added in an amount of 0.1 to 3% by weight based on the electron transport layer Manufacturing method. The method of claim 4, wherein
The electron transport layer,
(1) dissolving a water-soluble polymer having an electrophilic functional group;
(2) adding a surfactant to the polymer solution; And
(3) filtering the solution to form a thin film.
The method of claim 7, wherein
The water-soluble polymer having an electrophilic functional group is a poly [9,9-bis (6 '-(dietanolamino) hexyl) -fluorene] [PFN-OH] manufacturing method of high efficiency organic solar cell.
The method of claim 7, wherein
The surfactant is 2,4,7,9-tetramethyl-5-dekin-4,7-diol
(2,4,7,9-tetramethyl-5-decyne-4,7-diol) to 2-ethylhexanol, 2-butoxyethanol, dipropylene glycol electron transport layer by dissolving in at least one solvent selected from the group consisting of glycol, ethylene glycol, n-propyl alcohol, isopropyl alcohol, and propylene glycol Method for producing a high efficiency organic solar cell, characterized in that added to 0.1 to 3% by weight relative to.
The method of claim 7, wherein
The thin film is a method of manufacturing an organic solar cell, characterized in that the solution is coated with a thickness of 2 to 20nm heat treatment at 70 to 90 ℃.

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