KR20160018008A - P-doped conjugated polyelectrolyte and organic electronic devices using the same - Google Patents

Abstract

Provided are a p-doped conjugated polymer electrolyte containing a compound represented by chemical formula 1, and an organic electronic device applying the same as a hole transfer material. According to the present invention, a high efficiency solar cell and an OLED with high light emitting properties can be manufactured by verifying the type of an oxidizer and the type of a functional group applied to the p-type conjugated polymer to control electron density, and thus controlling doping intensity, thereby controlling work function change.

Description

P-DOPED CONJUGATED POLYELECTRONIC AND ORGANIC ELECTRONIC DEVICES USING THE SAME BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a P-doped conjugated polyelectrolyte and an organic electronic device using the same.

Organic light emitting devices (OLEDs) and organic solar cells (OSCs) are thin-film type, simple in structure, light in weight, easy to carry, low cost, And has been actively researched recently. However, due to the structural characteristics of the organic electronic device, it is necessary to control the energy level between the metal electrode and the organic material. To this end, various "interfacial layers" have been introduced between metal electrodes and organic materials. Such an interface layer effectively controls the work function of the electrode so as to establish an ohmic contact between the metal electrode and the organic material. Since the interfacial materials developed so far are characterized only by complicated deposition processes, they are not suitable for organic electronic devices that require printing techniques in practice. However, since the PEDOT: PSS polymer used as a typical hole transporting material can be subjected to a solution process, it has been reported that quenching of excitons occurs severely at the interface with the active layer, and because of the strong acidity, There is a problem that the lifetime and efficiency of the device are adversely affected. Conjugated polyelectrolytes (CPEs) and non-conjugated polyelectrolytes (non-CPEs), which have heretofore been used to enhance electron injection efficiency between a metal cathode and an organic material, The work function of the metal is "decreased ", so that it can not be used as an anode interface material which smoothes the flow of positive charge by increasing the work function of the metal.

One aspect of the present invention is to provide a p-doped conjugated polyelectrolyte which can be used as a hole transporting material for an organic electronic device because it has water-soluble and neutral properties and can be subjected to a solution process and oxidation of the anode.

Another aspect of the present invention is to propose an organic electronic device whose lifetime and efficiency are improved by using the p-doped conjugated polyelectrolyte as a hole transporting material.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to accomplish the above object, one aspect of the present invention provides a p-doped conjugated polyelectrolyte containing a compound represented by the following general formula (1).

≪ Formula 1 >

Wherein Ar < ₁ > is any one selected from the following group of compounds of Group 1a,

Ar < ₂ > is any one selected from the group of compounds 1b below or the second compound group below,

The superscript + in the square brackets represents the oxidized portion of the polymer backbone,

and m is an integer of 1 to 1,000,000.

≪ Group 1a compound >

Independently for each compound selected from said group 1a compound, at least one Y is -C _n H _2n ^- P ^- , wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and - CO ₂ ^- ), and the remaining Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, and P ^- is SO ₃ ^- , PO ₃ ^2- and CO _{2 -} ^- , Q ⁺ is any one selected from H ⁺ , Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ . And R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from C1-C11 alkyl groups, regardless of each other.

≪ Group 1b compound >

Independently for each compound selected from the first group of compounds, all Y is -C _n H _2n -P ^- Q ⁺ , wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , and Q ⁺ is any one selected from H ⁺ , Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ And R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from a C1-C11 alkyl group,

At least one Y is -C _n H _2n -P ^- (wherein n is an integer of 1 to 20, and P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and -CO ₂ ^- ), Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , Q ⁺ is H ⁺ Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from the group consisting of Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ , and N ⁺ R ₁ R ₂ R ₃ R ₄ . Are each independently selected from C1-C11 alkyl groups, regardless of each other.

≪ Second compound group >

Wherein the second group of compounds A is independently _{-H, -NR 2, -NH 2,} -OH, -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR _2, F, any one selected from Cl, Br, and I, and, B is each independently selected from _{-H, -R, -CH = CR 2} , F, Cl, any one selected from Br, and I, Z is independently _{-NR 2, -NH 2, -OH,} -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR 2, F, Cl, Br, And -C (= O) NR ₁ R ₂ , and W is each independently selected from -H and -R And R, R ₁ and R ₂ are independently H or a C1 to C20 alkyl group.

According to another aspect of the present invention, there is provided a plasma display panel comprising: a first electrode; A layer comprising the p-doped conjugated polyelectrolyte located on the first electrode; An organic active layer positioned on the polymer electrolyte layer; And a second electrode located on the organic active layer.

According to the present invention, it is possible to control the doping intensity by controlling the electron density by varying kinds of functional groups and oxidizing agents to be introduced into the p-type conjugated polymer, and consequently finely controlling the work function change. As a result, Lt; RTI ID = 0.0 > OLED < / RTI >

1 is a schematic view showing an organic electronic device according to an embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating a change in dipole and a work function of an electrode before and after P-doping of a P-doped conjugated polyelectrolyte according to an embodiment of the present invention. FIG.
FIG. 3 is a graph showing the relationship between the number of functional groups introduced into the p-type conjugated polymer according to one embodiment of the present invention (a), the type of oxidizing agent (b) And a comparison of the doping intensities with respect to each other.
FIG. 4 is a doping proof data comparing the absorption peaks when the kinds of the functional groups to be introduced into the p-type conjugated polymer are different under the same oxidant type.
FIG. 5 is a diagram illustrating the intramolecular and intramolecular doping mechanism of a p-type conjugated polymer according to an embodiment of the present invention.
6 is a graph comparing the size distributions of the p-type conjugated polymers in the case of different oxidants.
7 is a K-PFP (a), NH 4 -PFP (b), and Na-PFP (c) formed on the ITO electrode is the AFM image of a thin film.
8 is a graph comparing work functions of ITO electrodes employing a conjugated polymer doped with an undoped conjugated polymer and an ammonium ion as an interface layer.
9 is a graph comparing work functions of various electrodes employing a doped conjugated polymer with different oxidants.
10 is an energy diagram for a solar cell according to an embodiment of the present invention.
11 is a current density-voltage curve of a solar cell employing a doped conjugated polymer according to an embodiment of the present invention.
12 is a current density-voltage curve in the case where the p-type conjugated polymer according to an embodiment of the present invention is used as a hole transport layer and the conventional PEDOT: PSS is adopted as a hole transport layer.
13 is an energy diagram for an OLED according to an embodiment of the present invention.
FIG. 14 is a luminance-voltage curve of an OLED employing a P-type conjugated polymer, PEDOT: PSS, and a commercially available Plexcore as a hole transport layer according to an embodiment of the present invention.
15 is a luminous efficiency-luminance curve of an OLED employing a P-type conjugated polymer, PEDOT: PSS, and a commercially available Plexcore as a hole transport layer according to an embodiment of the present invention.
16 is a lifetime evaluation graph of an OLED employing a P-type conjugated polymer, PEDOT: PSS, and a commercially available Plexcore as a hole transport layer according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

The present invention relates to a P-doped conjugated polyelectrolyte and an organic electronic device using the same.

The inventors of the present invention have devised the present invention in order to adopt a conventional conjugated polymer which is difficult to be used as a hole transport layer as a neutral material without corrosion of electrodes and to use it as a new hole transporting material by controlling the work function through a simple operation .

Particularly, since the n-type conjugated polyelectrolytes (CPEs) exemplified in the following Formula 3, which has been used only as an electron transport layer (ETL), decrease the work function of the metal, ) Interface layer.

(3)

However, it has been confirmed that these n-type conjugated polyelectrolytes can be utilized as a p-type conjugated polymer electrolyte which operates as a hole transport layer (HTL) by oxidizing agents. The p-type conjugated polyelectrolyte thus formed forms dipoles opposite to each other in the n-type, and not only can the work function of the metal electrode in the electronic device be increased or decreased by 1 eV or more, Since the change of the work function can be finely controlled by the degree of doping, an anode in the organic electronic device can effectively make an ohmic contact with the organic material. (See Fig. 2)

The p-doped conjugated polyelectrolyte of the present invention contains a compound represented by the following formula (1).

≪ Formula 1 >

Wherein Ar < ₁ > is any one selected from the following group of compounds of Group 1a,

Ar < ₂ > is any one selected from the group of compounds 1b below or the second compound group below,

The superscript + in the square brackets represents the oxidized portion of the polymer backbone,

and m is an integer of 1 to 1,000,000.

≪ Group 1a compound >

Independently for each compound selected from said group 1a compound, at least one Y is -C _n H _2n ^- P ^- , wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and - CO ₂ ^- ), and the remaining Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, and P ^- is SO ₃ ^- , PO ₃ ^2- and CO _{2 -} ^- , Q ⁺ is any one selected from H ⁺ , Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ . And R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from C1-C11 alkyl groups, regardless of each other.

≪ Group 1b compound >

Independently for each compound selected from the first group of compounds, all Y is -C _n H _2n -P ^- Q ⁺ , wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , and Q ⁺ is any one selected from H ⁺ , Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ And R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from a C1-C11 alkyl group,

At least one Y is -C _n H _2n -P ^- (wherein n is an integer of 1 to 20, and P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and -CO ₂ ^- ), Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , Q ⁺ is H ⁺ Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from the group consisting of Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ , and N ⁺ R ₁ R ₂ R ₃ R ₄ . Are each independently selected from C1-C11 alkyl groups, regardless of each other.

≪ Second compound group >

Wherein the second group of compounds A is independently _{-H, -NR 2, -NH 2,} -OH, -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR _2, F, any one selected from Cl, Br, and I, and, B is each independently selected from _{-H, -R, -CH = CR 2} , F, Cl, any one selected from Br, and I, Z is independently _{-NR 2, -NH 2, -OH,} -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR 2, F, Cl, Br, And -C (= O) NR ₁ R ₂ , and W is each independently selected from -H and -R And R, R ₁ and R ₂ are independently H or a C1 to C20 alkyl group.

The p-doped conjugated polyelectrolyte has an oxidized portion in the main chain, the side chain may have a charge, and the charge opposite to the charge in the side chain may be a counter ion. Specifically, at least one of the side chains has an anion selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , and the p-doped conjugated polyelectrolyte may have additional side chains. The additional side chain may be any anion selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- and H ⁺ , Li ⁺ . And may have any one of cations selected from Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ , and N ⁺ R ₁ R ₂ R ₃ R ₄ as counter ions. Here, R ₁ , R ₂ , R ₃ , and R ₄ may be any one selected from C1-C11 alkyl groups, regardless of each other.

Also, the p-doped conjugated polyelectrolyte may include an electron donating group. "Electron donor group" means a C1-C24 alkyl, alkoxy, thioalkoxy, amine group, imine, carboxyl, phosphate, sulfonate group or combination thereof which may be substituted or unsubstituted, Quot; means substituted by a group that does not interfere with the desired product or method, for example, the substituent may be alkyl, alkoxy, and the like.

Specifically, the electron donor _{group, -NR 2, -NH 2, -OH} , -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CH 2 and -CH = CR ₂ , but is not limited thereto. These electron donor groups can provide electrons to the main chain of the conjugated polymer to enrich the electron density.

Also, the p-doped conjugated polyelectrolyte may include an electron withdrawing group. Wherein the electron acceptor group is selected from the group consisting of aryl, phenyl, halo (F, Cl, Br, I), -C (= O) R, -C (= O) OR, -C (= O) NR ₁ R _{2 1} and R < ₂ > are independently H or a C1-C20 alkyl group), but are not limited thereto. These electron acceptor groups can receive electrons from the main chain of the conjugated polymer to reduce the electron density of the main chain.

Doping of the p-doped conjugated polyelectrolyte can be controlled by appropriately combining the functional groups contained in the electron donor group and the electron acceptor group to finely control the work function change.

Meanwhile, the P-doped conjugated polyelectrolyte can be prepared by an oxidation reaction of a conjugated polyelectrolyte containing a compound represented by the following formula (4).

≪ Formula 4 >

Wherein Ar ₃ is any one selected from the following third compound group,

Ar ₂ is any one selected from the group of the following third compounds or the second group of compounds described below,

and m is an integer of 1 to 1,000,000.

≪ Third compound group >

In the third group of compounds, each X is independently -C _n H _2n -P ^- Q ⁺ (n is an integer from 1 to 20) and P ^- is selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- Q ⁺ is H ⁺ , Li ⁺ . Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently selected from the group consisting of Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ And R < 11 > are each independently selected from C1-C11 alkyl groups.

≪ Second compound group >

Wherein the second group of compounds A is independently _{-H, -NR 2, -NH 2,} -OH, -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR _2, F, any one selected from Cl, Br, and I, and, B is each independently selected from _{-H, -R, -CH = CR 2} , F, Cl, any one selected from Br, and I, Z is independently _{-NR 2, -NH 2, -OH,} -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR 2, F, Cl, Br, And -C (= O) NR ₁ R ₂ , and W is each independently selected from -H and -R And R, R ₁ and R ₂ are independently H or a C1 to C20 alkyl group.

The oxidation reaction of the conjugated polyelectrolyte represented by Formula 3 is not particularly limited. For example, oxidation or oxidation may be induced by adding an acid or an oxidizing agent to the conjugated polyelectrolyte, or a polymer electrolyte membrane may be formed by coating the conjugated polyelectrolyte Oxidation of the polymer electrolyte can be induced using CV (cyclo voltammetry).

(9,9-bis (4'-sulfonatobutyl) fluorene- alt - co- 1,4-phenylene (PFP), which is a kind of n-type conjugated polyelectrolytes (n-CPEs) Treatment of 9-bis (4'-sulfonatobutyl) (fluorine- alt - co- 1,4-phenylene) with an oxidizing agent persulfate gives p-doped conjugated polyelectrolytes (p-CPEs) Can be expressed by the following equation (1).

[Reaction Scheme 1]

X in SO ₃ ^- X ⁺ in Scheme 1 may be Li, K, NH ₄ , or Na. In the above Reaction Scheme 1, persulfate is XHSO ₅ (where X = K); X ₂ S ₂ O ₈ wherein X = Na, K, Li, Rb, Cs, or NH ₄ ; XS ₂ O ₈ (where X = Ba, Zn, Ca, Be, Mg, Sr, Ti, or Fe); X ₂ (S ₂ O ₈ ) ₃ (where X = Sb, Al, or V); X (S ₂ O ₈ ) ₂ (where X = Ti); X ₂ (S ₂ O ₈ ) ₅ (where X = V), and the like. In the above Reaction Scheme 1, R ₁ and R ₂ each independently may be an electron donating group such as a halogen group such as -F, -Cl, -Br, -I, or -OMe, but is not limited thereto. For convenience, the p- doped conjugated polymer electrolyte produced on the right side of the scheme 1 may be represented by R ₁ = -H, and R when the _{2 = -H X-PFP, R} 1 = -H , and R ₂ = -F Is X-PFP-OMe when R ₁ = -H and R ₂ = -OMe (methoxy group), and when X ₁ is -OMe and R ₂ = -OMe, X -PFP-O. ≪ / RTI >

As a preferred embodiment, the p-doped conjugated polyelectrolyte may be a compound represented by the following formula (2).

(2)

Wherein X is any one of Li, Na, K, Rb, Cs and NH ₄ , the superscript + in the square brackets denotes an oxidized portion in the polymer main chain, and m is an integer of 1 to 1,000,000.

1 is a schematic view showing an organic electronic device 100 according to an embodiment of the present invention.

Referring to FIG. 1, a first electrode 120, an electrolyte layer 130 including a p-doped conjugated polyelectrolyte, an organic active layer 140, an electron transport layer 150, (160) may be sequentially formed. Here, the electron transport layer 150 may be omitted.

The substrate 110 is used to support organic electronic devices, and may be a light-transmissive inorganic substrate selected from the group consisting of glass, quartz, Al ₂ O _3, and SiC, or a transparent substrate made of PET (polyethylene terephthalate), PES (polyethersulfone) transparent plastic substrate selected from polycarbonate, PI (polyimide), PEN (polyethylene naphthalate) and PAR (polyarylate).

The first electrode 120 may be a light transmitting electrode. The first electrode 120 may be an indium tin oxide (ITO) film, a fluorinated tin oxide (FTO) film, an indium zinc oxide (IZO) film, a zinc oxide (AZO) Indium Zinc Tin Oxide) film.

The p-doped conjugated polyelectrolyte layer 130 has an oxidized portion in the main chain and has a charge in the side chain and a charge opposite to the charge in the side chain. The p-doped conjugated polyelectrolyte layer 130 has a counter ion and has a conjugated polymer.

Specifically, the side chain may have any one of anions selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , and H ⁺ , Li ⁺ . ^{Na +, K +, Rb +} , Cs +, N + H 4, and ^{_{N + R 1 R 2 R 3}} R 4 can have any one of a cation selected from the group consisting of a counter-ion (wherein, R _1, R ₂ , R ₃ , and R ₄ are each independently selected from a C1-C11 alkyl group.

The p-doped conjugated polyelectrolyte layer 130 can easily transport the holes supplied through the external circuit from the first electrode 120 to the organic active layer 140 (in the case of an organic light emitting device) And may serve as a hole transport layer for easily transporting holes generated in the active layer 140 to the first electrode 120 (in the case of an organic solar cell). In addition, the p-doped polyelectrolyte layer 130 may serve as a buffer layer for reducing the surface roughness of the first electrode 120. The LUMO (Lowest Unoccupied Molecular Orbital) level of the p-doped polyelectrolyte layer 130 is higher than the LUMO level of the organic active layer 140 so that electrons flow from the organic active layer 140 to the first electrode 120 It may also serve as an electronic blocking layer.

The p-doped conjugated polyelectrolyte layer 130 may contain a compound represented by the above-described formula (1).

In addition, as a preferred embodiment, the p-doped conjugated polyelectrolyte layer 130 may contain a compound represented by the above-described formula (2).

The organic active layer 140 may be a light emitting layer or a photoelectric conversion layer. Here, the light emitting layer refers to a layer that generates light by the combination of electrons and holes supplied from the outside. The photoelectric conversion layer is a layer in which electrons and holes (excitons) Is a layer in which separation occurs. When the organic active layer 140 is formed of a light emitting layer or a photoelectric conversion layer, the organic electronic device 100 may be an organic light emitting device or an organic solar cell.

The materials of the light emitting layer and the photoelectric conversion layer are not particularly limited, and various polymers or low molecular organic materials may be used.

For example, the material of the light emitting layer may be one selected from the group consisting of polyaniline, polypyrrole, polyacetylene, poly (3,4-ethylenedioxythiophene), PEDOT, Polyphenylenevinylene (PPV), polyfluorene, polyparaphenylene (PPP), polyalkylthiophene, polypyridine (PPy), polyvinyl carbazole polyvinylcarbazole, copolymers thereof, or may be selected from suitable host / dopant materials.

For example, the material of the electron donor of the photoelectric conversion layer may be a polythiophene series, a polyfluorene series, a polyaniline series, a polycarbazole series, a polyvinyl carbazole series, polyvinylcarbazole type, polyphenylene type, polyphenylvinylene type, polysilane type, polyisothianaphthanene type, polythiazole type, polybenzothiazole type, A polybenzothiazole type, a polythiopheneoxide type, or a copolymer thereof. For example, the electron donor material may be poly (3-hexylthiophene) (P3HT), which is a kind of the polythiophene type, or PCPDTBT (poly [2,6- (2,1-b, 3,4-b '] dithiophene) -tallow-4,7- (2,1,3-benzothiadiazole)], PCDTBT (poly [N-9 "-heptadecanyl-2,7-carbazolealt-5,5- (4 ', 7'-di-2-thienyl-2', 1 ', 3'-benzothiadiazole)] or PFDTBT 5 '- (4', 7'-di-2-thienyl-2 ', 1 ', 3 ' For example, the electron acceptor material of the photoelectric conversion layer may be a fullerene or a derivative thereof of C ₆₀ to C ₈₄ , a perylene, a polymer, or a quantum dot ) may be a fullerene derivative PCBM as, an _{example, PCBM (C 60) ([} 6,6] -phenyl-C 61 -butyric acid methyl ester) or _{PCBM (C 70) ([6,6} ]. - phenyl-C ₇₁ -butyric acid methyl ester).

The electron transport layer 150 can easily transport electrons supplied through an external circuit from the second electrode 160 to the organic active layer 140 (in the case of an organic light emitting device) (In the case of an organic solar cell) for easily transporting electrons to the second electrode 160. In addition, the electron transport layer 150 may serve as a hole blocking layer to prevent holes generated in the organic active layer 140 from flowing into the second electrode 150. The electron transport layer 150 may be, for example, a titanium oxide layer. The titanium oxide layer may prevent deterioration of the device due to penetration of oxygen or water vapor into the organic active layer 140 and increase the amount of light introduced into the organic active layer 140 spacer), and can also serve as a lifetime enhancement layer that increases the lifetime of the organic electronic device. The titanium oxide layer may be formed using a sol-gel method.

The second electrode 160 may have a smaller work function than the first electrode 120, and may be a metal or a conductive polymer electrode. In one embodiment, the second electrode 160 is formed of a material selected from the group consisting of Li, Mg, Ca, Ba, Al, Cu, Ag, Au, W, Ni, Zn, Ti, Zr, Hf, Cd, Pd, And may be any one selected from metal electrodes. When the second electrode 160 is a metal electrode, the second electrode 160 may be formed by thermal vapor deposition, electron beam deposition, sputtering, or chemical vapor deposition, or may be formed by applying an electrode forming paste containing a metal, followed by heat treatment. However, the present invention is not limited thereto.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the following examples are only for illustrating the present invention in more detail and do not limit the scope of the present invention.

[Example]

Production Example 1: Synthesis of Conjugated Polyelectrolytes (CPEs)

[Reaction Scheme 2]

<Example 1-1> Synthesis of intermediate product (monomer)

2,7-dibromo-9H-fluorene (2.0 g, 15.4 mmol) and a small amount of triethylbenzylammonium chloride were dissolved in 30 ml of DMSO, and a solution of NaOH Aqueous solution (H2O (4 mL) + NaOH (2.0 g, 50.0 mmol)). After stirring for 30 minutes, 1,4-butanesultone (2.1 g, 15.4 mmol) was added to the reaction mixture. After vigorously stirring at 100 DEG C for 12 hours under argon (Ar) gas, the mixture was cooled to room temperature and mixed with 100 mL of acetone. The precipitate was filtered and washed with acetone to give sodium 4- (2,7-dibromo-9 (4-sulfonato) -9H-fluoren-9-yl) butyl sulfate as a pale yellow solid (yield 80-90% Sodium 4- (2,7-dibromo-9 (4-sulfonatobutyl) -9H-fluoren-9yl) butyl sulfate) monomer.

The NMR chemical shift of the obtained monomer is as follows.

^{1 H NMR (400 MHz, DMSO-} d 6, δ ppm): 7.73-7.71 (d, 2H, J = 8.00 Hz), 7.66-7.65 (d, 2H, J = 1.70 Hz), 7.47-7.44 (dd, 2H, J = 8.00 Hz, J = 1.70 Hz), 2.10-2.05 (m, 4H), 2.00-1.95 (m, 4H), 1.31-1.23 (m, 4H), 0.40-0.30 (m, 4H).

<Example 1-2> Synthesis of n-type CPEs through polymerization of monomers

The above monomer (1.28 g, 2.0 mmol) and 1,4-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzene, 2,2'- (2-fluoro-1,4-phenylene) bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolane), or 2,2 '- (2,5-dimethoxy- ) bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (2.0 mmol) was dissolved in 54 mL of DMF / 0 / 2M NaCO ₃ (aq) (4/5, v / v) The solution was degassed with argon for 15 min. Pd (OAc) ₂ (22.5 mg, 0.05 mol%) was then added to the solution under argon. The reaction mixture was heated to 100 &lt; 0 &gt; C and stirred for 12 hours. The viscous solution was mixed with 300 mL of acetone. The precipitate was dissolved in water and purified by dialysis using a 12 kD fraction molecular weight regenerated cellulose membrane. After dialysis, water was removed using a low temperature drying method. Solids of light yellow (PFP), light orange (PFP-F) and light pink (PFP-O), respectively, were obtained as water-soluble CPEs in a yield of 40%.

The NMR chemical shift of each material is as follows.

PFP. ¹ H NMR (400 MHz; DMSO- d ₆ ,? _Ppm ): 7.97-7.36 (m, 10H), 2.33-2.08 (m, 8H), 1.42 (br, 4H), 0.69 (br, 4H).

PFP-F. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 8.30-7.19 (m, 9H), 2.28 (br, 4H), 2.13 (br, 4H), 1.43 (br, 4H), 0.69 (br, 4H); ^{13 C NMR (150 MHz, DMSO-} d 6, δ ppm): 163.7, 160.6, 158.9, 151.5, 150.9, 143.0, 141.8, 140.1, 139.9, 137.8, 134.0, 131.3, 128.0, 127.2, 125.9, 125.0, 123.4, 121.2, 116.1, 116.0, 114.3, 114.2, 55.2, 55.0, 54.8, 51.4, 34.5, 25.5, 23.2.

PFP-O. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 8.28-6.90 (m, 8H), 2.30 (br, 4H), 2.02 (br, 4H), 1.43 (br, 4H), 0.76 (br, 4H); ^{13 C NMR (150 MHz, DMSO-} d 6, δ ppm): 153.5, 151.1, 150.5, 150.4, 150.1, 150.0, 149.8, 139.1, 139.0, 136.9, 136.7, 131.2, 129.9, 128.0, 127.0, 124.2, 124.1, 119.5, 119.4, 116.0, 115.8, 114.8, 113.4, 113.3, 56.4, 56.2, 55.5, 55.4, 54.4, 51.3, 51.2, 34.3, 25.3, 23.2.

Example 1-3 Synthesis of P-type CPEs

To the aqueous solution obtained by dissolving 0.005 g of CPEs (PFP, PFP-F or PFP-O) obtained above in 1.0 mL of water was added the oxidizing agent X ₂ S ₂ O ₈ (X = K, Na, or 3.0 mol of NH ₄ and 1.0 mL of water The orange precipitate was collected by vacuum filtration and washed with 100 mL of cold deionized water, dried overnight in the hood to give slightly yellow p-doped CPEs (X-PFP, X- PFP-F, X-PFP-O) in 90-100% yield.

The NMR chemical shift of each material is as follows.

K-PFP. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 8.10-7.38 (m, 10H), 2.20 (br, 8H), 1.39 (br, 4H), 0.66 (br, 4H); ¹³ C NMR (150 MHz, DMSO- d ₆ ,? _Ppm ): 151.5, 139.7, 139.4, 138.9, 129.1, 127.5, 127.0, 125.8, 121.2, 120.6, 55.0, 51.4, 25.5, 23.3.

NH ₄ -PFP. ¹ H NMR (600 MHz, DMSO- d ₆ ,? _Ppm ): 8.10-7.48 (m, 10H), 2.27 (br, 8H), 1.44 (br, 4H) 0.71 (br, 4H); ¹³ C NMR (150 MHz, DMSO- d ₆ ,? _Ppm ): 151.5, 139.4, 138.9, 129.1, 127.5, 127.2, 127.0, 125.8, 121.3, 120.7, 51.4, 25.4, 23.2.

Na-PFP. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 8.20-7.40 (m, 10H), 2.21 (br, 8H), 1.40 (br, 4H), 0.56 (br, 4H); ^{13 C NMR (150 MHz, DMSO-} d 6, δ ppm): 174.6, 173.4, 168.7, 163.4, 130.2, 129.7, 129.5, 128.8, 127.2, 124.4, 72.2, 69.9, 51.2, 51.0, 50.5, 34.6, 32.8, 29.2, 20.8.

NH ₄ -PFP-F. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 7.99-7.64 (m, 9H), 2.27 (br, 4H), 2.09 (br, 4H), 1.42 (br, 4H) 0.68 (br, 4H ); ^{13 C NMR (150 MHz, DMSO-} d 6, δ ppm): 162.3, 160.4, 158.8, 157.6, 151.6, 150.9, 148.2, 146.3, 141.4, 131.4, 127.0, 125.9, 123.6, 123.4, 121.5, 120.4, 114.4, 113.5, 51.2, 35.8, 25.5, 23.2.

NH ₄ -PFP-O. ^{1 H NMR (600 MHz, DMSO-} d 6, δ ppm): 8.14-7.57 (m, 8H), 2.29 (br, 4H), 2.04 (br, 4H), 1.43 (br, 4H) 0.70 (br, 4H ); ^{13 C NMR (150 MHz, DMSO-} d 6, δ ppm): 186.9, 162.4, 150.5, 150.1, 124.3, 120.2, 114.8, 79.2, 79.0, 56.5, 56.3, 55.5, 54.7, 54.4, 51.3, 35.8, 34.4, 30.8, 25.3, 24.9, 23.1.

Analysis Example 1: Characterization of CPEs

Fig. 3 shows the result of electron spin resonance (ESR) analysis. No signal is seen in the unoxidized CPEs (PFP, PFP-F, PFP-O), but treated with persulfate X ₂ S ₂ O ₈ (X = K, Na, NH ₄ ) to produce p-doped CPEs X-PFP, X-PFP-F and X-PFP-O). The intensity of the ESR signal is proportional to the unpaired spin density on the relative cation of the persulfate, and the intensity of the signal decreases in the order of Na ⁺ > NH ₄ ⁺ > K ⁺ . This means that the oxidation potential of the electrolyte containing Na &lt; ⁺ > will be higher. As a result of ESR analysis, the electrolyte with different functional groups was treated with the same persulfate (NH ₄ ) ₂ S ₂ O ₈ , and the results were analyzed in the order of NH ₄ -PFP-O> NH ₄ -PFP> NH ₄ -PFP-F (Fig. 3). This suggests that the high electron density in the NH ₄ -PFP-O backbone generates a high oxidation potential, resulting in an increase in the ESR signal intensity. Higher oxidation potentials generate more radical cations on the CPEs backbone, effectively producing polaron-induced dipoles. The sulfonate anion stabilizes the positively charged (oxidized) main chain as a counter ion, and interacts in the molecule or between molecules as shown in FIG. 5 to produce polymer aggregates.

Figure 4 shows the absorption spectra of conventional n-type CPEs and p-doped CPEs. As oxidation progressed, the polaron band absorption at low energy (400-600 nm) increased and the π-π * transition at 354 nm shifted slightly to higher energy. This change means that the electron density in the resonating main chain is increased.

The intensity of the dipole can be controlled by combining a combination of an electron withdrawing group and an electron donating group (electron donating group) in the CPE backbone. It was observed that the increase in the effective work function was large in an ITO electrode employing an electrolyte having a main chain having a large electron density such as NH ₄ -PFP-O (FIG. 8). It is assumed that NH ₄ -PFP-O with a low ionization potential forms a stronger dipole because it can be easily oxidized. The same results were obtained when the types of electrodes were changed to Ag, graphene (GR), Au, and Cu (FIG. 9).

Production Example 2: Production of solar cell

&Lt; Example 2 >

ITO / HTL / PTB7 (or PTB7-Th): Bulk Hetero Junction (BHJ) of PC ₇₁ BM / ETL / Al structure was used to confirm the work function change of the metal electrode employing p-doped CPEs as a hole transport layer ) Solar cell. Here, PC ₇₁ BM of the photoelectric conversion layer means [6,6] -phenyl C ₇₁ -butyric acid methyl ester as a polymer, and the photoelectric conversion layer contains two donor polymers PTB7 or PTB7-Th (FIG. 10) . Sol-gel based titanium oxide (TiOx) or PFN was used as the electron transport layer (ETL).

A methanol solution (0.02 wt%) of X-CPEs was applied to an ITO / glass substrate by a spin casting method to form a 2 nm thick thin film.

A mixture of donor PTB7 or PTB7-Th (1-Material, Inc.) and acceptor PC ₇₁ BM (Solenne BV) (1: 1.5) was added to a chlorobenzene / 1,8- diiodooctane (97: To the total concentration of 25 mg / ml was spin-cast on the X-CPE thin film to form a photoelectric conversion layer. A methanol solution of TiO x (TiO x: methanol = 1: 300 volume ratio) or a PFN methanol solution (containing 0.1 wt% PFN and a small amount of acetic acid) in air was spin cast on the photoelectric conversion layer, Lt; / RTI &gt; Finally, Al (100 nm) was deposited by thermal evaporation under high vacuum (5 × 10 ^-7 Torr).

&Lt; Comparative Example 2 &

For comparison, except that PEDOT: PSS (Clevios AI 4083) aqueous solution was applied to ITO / glass substrate by spin cast method instead of X-CPEs and baked in air at 150 ° C for 10 minutes to prepare PEDOT: PSS thin film A solar cell was manufactured under the same conditions as in Example 2. [

Analysis Example 2: Characterization of solar cell

Table 1 summarizes the effective work function for a solar cell employing various conjugated polyelectrolytes as an HTL and the parameters indicating the performance of a solar cell. When the P-doped conjugated polymer (X-PFP or NH ₄ -PFP-O, where X = K, NH ₄ , Na) was employed as the HTL, the photoelectric conversion efficiency (PCE) And the PCE of the p-un-doped conjugated polymer (PFP) was as low as about 0.1%.

FIG. 11 shows current density-voltage characteristics of a device employing p-doped CPEs and non-p-doped CPEs as HTLs, respectively. NH ₄ -PFP>Na-PFP>K-PFP> PFP. In the case of NH ₄ -PFP, p-doped CPEs showed the best characteristics. The least. Table 1 also shows that the PCE value of NH ₄ -PFP is excellent at 7.8%, which means that the HOMO level of PTB7 of the photoactive layer matches well with the work function, which is important for improving the performance of the BHJ solar cell. In addition, although the Na-PFP exhibited a high oxidation potential (Fig. 3), the particle size reached about 10,000 nm and the surface of the thin film was rough (Fig. 7). On the other hand, NH ₄ -PFP has a good particle size of less than 5000 nm (FIG. 6), a thin film having a relatively smooth surface (FIG. 7) and a good oxidizing potential (FIG. 3) .

Figure 12 shows the current density-voltage characteristics of a device employing NH ₄ -PFP-O and PEDOT: PSS as the HTL and PFN as the ETL, respectively, showing the largest effective work function (5.6 eV). The PEDOT: PSS (15.8mA / ㎠) was improved by about 1mA / ㎠ more than the PEDOT: PSS, and the current density was 16.7mA / ㎠, (8.9%) than in the case of Korea.

HTL Effective WF (eV) Solar cell parameters KP UPS ETL Donor Material V _oc
(V) J _sc
(mA cm ^-2 ) FF
(%) PCE (%) ITO Ag Au Cu GR ITO Best Average 4.80 4.68 5.00 4.70 4.76 4.82 TiO _x PTB7 0.67 14.1 53 4.9 4.7 ± 0.2 PFP 4.37 TiO _x PTB7 0.27 2.3 13 0.1 K-PFP 5.04 4.86 5.14 4.89 4.93 4.99 TiO _x PTB7 0.64 14.9 42 4.0 3.7 ± 0.2 NH ₄ -PFP 5.18 4.95 5.21 4.92 5.01 5.05 TiO _x PTB7 0.75 15.3 68 7.8 7.6 ± 0.1 Na-PFP 5.35 5.03 5.26 4.95 5.08 5.14 TiO _x PTB7 0.72 15.3 65 7.2 6.9 ± 0.1 NH ₄ -PFP-O 5.56 5.26 TiO _x PTB7-Th 0.79 15.8 70 8.7 8.5 ± 0.1 PFN PTB7-Th 0.79 16.7 71 9.4 9.2 ± 0.1 PEDOT: PSS 5.05 5.03 5.07 5.01 5.03 5.10 TiO _x PTB7-Th 0.79 15.5 70 8.5 8.4 ± 0.1 PFN PTB7-Th 0.79 15.8 72 8.9 8.8 ± 0.1

Production Example 3: Preparation of organic light emitting diode (OLED)

&Lt; Example 3 >

OLEDs with ITO / NH ₄ -PFP-O / Super Yellow / Ca / Al structures were fabricated to evaluate the performance of OLEDs using p-doped CPEs as HTLs. Here, poly ( p- phenylene vinylene) derivative (Super Yellow, SY) was used as a light emitting layer.

A methanol solution (0.5 wt%) of NH ₄ -PFP-O was applied to an ITO / glass substrate by a spin casting method to form a thin film.

an aryl-substituted poly ( p- phenylenevinylene) derivative (Super Yellow, Merck, Inc.) toluene solution (0.5 wt%) was spin cast on the NH ₄ -PFP-O thin film to form a light emitting layer. It was then baked in a glove box at 80 ° C for 10 minutes. Finally, an Al (100 nm) -capped Ca (20 nm) electrode was deposited by thermal evaporation under high vacuum (5 × 10 ^-7 Torr).

&Lt; Comparative Example 3 &

The NH ₄ -PFP-O instead For comparison PEDOT: PSS (Clevios AI 4083) aqueous solution or ^{Plexcore ® RG-1200 (Sigma Aldrich} , Inc.) by applying the aqueous solution to the ITO / glass substrate using a spin casting method PEDOT: PSS in a thin film of air 150 ℃, Plexcore ^® thin film OLED was prepared under the same conditions as in example 3 except that move in a glove box in order to dry after forming the light emitting layer for 10 minutes in a 160 ℃ air.

Analysis Example 3: Characterization of OLED

14 and FIG. 15 is a HTL PEDOT: PSS, Plexcore ^® NH ₄ and the case of using the O--PFP luminance (L) for each-represents the luminance (L) - voltage (V), luminous efficiency (LE). The maximum L ( L ~ 46,000 cd m ^-2 ) of NH ₄ -PFP-O is slightly lower than that of the device using PEDOT: PSS ( L ~ 44,000 cd m ^-2 ) or Plexcore ^® ( L ~ 28,000 cd m ^-2 ) Respectively. However, LE ( LE ~ 7.1 cd A ^-1 ) of the NH ₄ -PFP-O device is significantly higher than that of PEDOT: PSS ( LE ~ 5.1 cd A ^-1 ) and Plexcore ^® ( LE ~ 6.4 cd A ^-1 ) appear.

In order to evaluate the lifetime of the device, the operation time ( t _1/2 ) of the device up to the time when the luminance ( L ) becomes half (1/2) of the initial luminance ( L ₀ ) was measured (FIG. NH ₂ -PFP-O device is 272 min, which is 2 to 5 times longer than PEDOT: PSS (136 min) or Plexcore ^® (46 min). This is because the pH value of PEDOT: PSS and Plexcore ^® (PEDOT: PSS: 1.2 ~ 2.2, Plexcore ^® : 2.2 ~ 2.6) is an acidic region which causes deterioration of the device due to corrosion of the ITO electrode, Phenomenon. On the other hand, the NH ₄ -PFP-O solution of the present invention has a neutral pH (6.7 to 7.0), which is free from such a problem.

Claims (6)

A p-doped conjugated polyelectrolyte containing a compound represented by the following formula
&Lt; Formula 1 >

Wherein Ar < ₁ > is any one selected from the following group of compounds of Group 1a,
Ar < ₂ > is any one selected from the group of compounds 1b below or the second compound group below,
The superscript + in the square brackets represents the oxidized portion of the polymer backbone,
and m is an integer of 1 to 1,000,000.

&Lt; Group 1a compound >

(Independently for each compound selected from the group of compounds 1a), at least one Y is -C _n H _2n ^- P ^- , wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and -CO ₂ ^- ), and the remaining Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, and P ^- is SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , and Q ⁺ is any one selected from H ⁺ , Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ and N ⁺ R ₁ R ₂ R ₃ R ₄ And R ₁ , R ₂ , R ₃ , and R ₄ are each independently any one selected from a C 1 to C 11 alkyl group.)

&Lt; Group 1b compound &gt;

(Independently for each compound selected from the group of compounds 1b above, all Y is -C _n H _2n -P ^- Q ⁺ wherein n is an integer from 1 to 20 and P ^- is SO ₃ ^- , PO ₃ ^2- and CO ₂ ^-. and any one is selected from, Q ⁺ is ^{H +, Li + Na +,} K +, Rb +, Cs +, N + H 4, and ^{_{N + R 1 R 2 R 3}} R 4 is selected from And R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from a C1-C11 alkyl group,
At least one Y is -C _n H _2n -P ^- (wherein n is an integer of 1 to 20, and P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and -CO ₂ ^- ), Y is -C _n H _2n -P ^- Q ⁺ (n is an integer of 1 to 20, P ^- is any one selected from SO ₃ ^- , PO ₃ ^2- and CO ₂ ^- , Q ⁺ is H ⁺ Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from the group consisting of Li ⁺ . Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , N ⁺ H ₄ , and N ⁺ R ₁ R ₂ R ₃ R ₄ . Are each independently selected from C1-C11 alkyl groups, regardless of each other).

&Lt; Second compound group &gt;

(Wherein the second compound group A are each independently _{-H, -NR 2, -NH 2,} -OH, -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR ₂ , F, Cl, Br and I, and B is independently selected from -H, -R, -CH = CR ₂ , F, Cl, Br and I , Z are each independently selected from _{-NR 2, -NH 2, -OH,} -OR, -NHC (= O) R, -OC (= O) R, -R, -CH = CR 2, F, Cl, Br , And I, -C (= O) R, -C (= O) OR, -C (= O) NR ₁ R ₂ , W is independently selected from -H and -R And R, R ₁ and R ₂ are independently H or a C1-C20 alkyl group.
The method according to claim 1,
Wherein the p-doped conjugated polyelectrolyte is a compound represented by the following formula (2): p-doped conjugated polyelectrolyte:
(2)

Wherein X is any one of Li, Na, K, Rb, Cs and NH ₄ , the superscript + in the square brackets denotes an oxidized portion in the polymer main chain, and m is an integer of 1 to 1,000,000.
A first electrode;
A layer comprising a p-doped conjugated polyelectrolyte according to any one of claims 1 to 2 positioned on the first electrode;
An organic active layer positioned on the polymer electrolyte layer; And
And a second electrode located on the organic active layer.
The method of claim 3,
Wherein the organic active layer is a light emitting layer or a photoelectric conversion layer.
The method of claim 3,
And an electron transport layer disposed between the organic active layer and the second electrode.
The method of claim 3,
Wherein the electron transport layer is a titanium oxide layer.

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