KR101458691B1 - Organic solar cell including hybrid conductive thin film having a high work function and conductivity - Google Patents

Abstract

Organic solar cells including high-work function and high-conductivity hybrid conductive thin films are provided.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic solar cell including a high-work function and a high-conductivity hybrid-conductive thin film.

To an organic solar cell using a conductive thin film.

At present, indium tin oxide (ITO) transparent electrodes are widely used as essential components in various devices such as solar cells, display devices and the like.

 Oxidized electrodes such as ITO have high electrical conductivity and transparency but they are vulnerable to bending. The resistance is increased due to the crack generated when the ITO transparent electrode is bent, and it is difficult to reuse after the crack is generated. In addition, indium, which is the main material of ITO, is not only high in price but also easy to process, and as the demand increases, the cost of raw material increases.

Accordingly, other types of transparent electrode materials that can replace the conventional ITO transparent electrode material have been developed, but the work function has not reached a satisfactory level. In addition, since conventional ITO transparent electrodes are difficult to apply to flexible electronic devices, development of transparent flexible electrodes is required.

And to provide an organic solar cell employing a high-work function and high-conductivity hybrid conductive thin film which can replace the conventional ITO transparent electrode material.

According to an aspect, A first electrode; A second electrode; And a photoactive layer disposed between the first electrode and the second electrode,

Wherein at least one of the first electrode and the second electrode comprises:

And a second surface opposite the first surface, wherein the concentration of the low-surface energy material in the second surface is greater than the concentration of the low-surface energy material in the second surface, A work function-tuning layer that is greater than the concentration of the low-surface energy material of the first side and the work function of the second side is at least 5.0 eV; And

Metal carbon nanotubes, graphene, reduced graphene oxide, metal nanowires, metal grids, semiconductor nanowires, and the like, which have excellent bending stability while replacing metal oxide electrodes. A conductivity-tuning layer comprising at least one of a metal-on-insulator and a metal nano-dot, the conductivity-tuning layer not including the low-surface energy material and in contact with a first side of the work function-control layer;

And a hybrid conductive thin film having a high work function and conductivity, wherein the hybrid conductive thin film has a conductivity of 1 S / cm or more,

And a second side of the work function-control layer faces the photoactive layer.

Wherein the first electrode is a high-work function and high-conductivity hybrid conductive thin film, the first electrode is an anode, and the work function-control layer is a layer between the substrate and the photoactive layer As shown in FIG.

The concentration of the low-surface energy material may gradually increase from the second surface to the first surface.

The low-surface energy material may be a fluorinated material including at least one F.

Since the high-work function and high-conductivity hybrid conductive thin film have a work function-control layer and a conductivity-control layer at the same time, both work function and conductivity can be improved. Therefore, the organic solar cell employing the high-work function and high-conductivity hybrid thin film as an electrode can have excellent photoelectric conversion efficiency even if the hole extraction layer for controlling work function is omitted, - Conductivity Hybrid conductive thin films can contribute to simplifying the structure of organic solar cells. Thus, the manufacturing cost of the organic solar battery can be reduced. In addition, the high-work function and high-conductivity hybrid conductive thin film can replace non-flexible electrodes such as conventional ITO electrodes, which can contribute to the realization of flexible organic solar cells.

1 is a view schematically illustrating a cross section of one embodiment of the organic solar cell.
2 is a view schematically illustrating a cross section of another embodiment of the organic solar cell.
3 is an XPS spectrum showing the molecular distribution of the work function-control layer 4 produced in Example 1 by sputtering time.
FIG. 4 is a graph of hole injection efficiency of the work function-control layers 1 to 4 prepared in Example 1. FIG.
5 is a graph of current-voltage of OPV 1 and OPV A to C prepared in Example 1 and Comparative Examples 1 to 3.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The organic solar cell 200 of FIG. 1 includes a substrate 210, a first electrode 1, a photoactive layer 240, an electron transport region 250, and a second electrode 260. The light irradiated to the organic solar cell 200 is separated into holes and electrons in the photoactive layer 240 so that electrons move to the second electrode 260 through the electron receiving region 250 and holes move to the first electrode 1, . ≪ / RTI >

The first electrode (1)

CLAIMS What is claimed is: 1. A device comprising: i) a conductive polymer and a material having a low surface energy and having a first side 230A and a second side 230B opposite the first side 230A, Wherein the concentration of the low-surface energy material of the surface 230B is greater than the concentration of the low-surface energy material of the first surface 230A and the work function of the second surface 230B is 5.0 eV or higher, A work function-tuning layer 230; And

Metal carbon nanotubes, graphene, reduced graphene oxide, metal nanowires, metal grids, semiconductor nanowires, and the like, which have excellent bending stability while replacing metal oxide electrodes. And a metal nano-dot, wherein the conductivity-control layer (230), which does not include the low-surface energy material and is in contact with the first side (230A) of the work- layer 220;

And a hybrid conductive thin film having a high work function and conductivity, having a conductivity of at least 1 S / cm. The first electrode 1 serves as an anode.

In the present specification, the term "low-surface energy material" refers to a material capable of forming a film having a low surface energy, specifically, a material having a surface energy lower than that of the conductive polymer. In the mixture of the low-surface energy material and the conductive polymer, phase separation occurs due to a difference in surface energy between the low-surface energy material and the conductive polymer, a low-surface energy material forms an upper phase, And the polymer forms a lower phase. The low-surface energy material is a material including at least one F, and may have a hydrophobicity greater than that of the conductive polymer. In addition, the low-surface energy material may be a material capable of providing a work function greater than the work function of the conductive polymer. For example, the low-surface energy substance, the low - has a thin film of 100nm thickness of the surface energy of less than 30mN / m made of a surface energy materials, which have a conductivity of 10 ^-1 to 10 ^-15 S / cm Lt; / RTI > Also, a thin film of 100 nm thick prepared using the conductive polymer composition containing the low-surface energy material has a surface energy of 30 mN / m or less and has a conductivity of 10 ^-1 to 10 ^-7 S / cm Lt; / RTI >

Thus, when a film comprising the conductive polymer and a mixture comprising the low-surface energy material is formed on the conductivity-control layer 220, the low surface energy of the low-surface energy material causes the conductive polymer and the low- Are not homogeneously mixed. Instead, the concentration of the low-surface energy material has a slope that gradually increases along the direction from the first surface 230A toward the second surface 230B, and the concentration of the conductive polymer is relatively higher than the first The conductive polymer and the low-surface energy material may be distributed so as to have a gradually increasing inclination along the direction from the surface 230A toward the second surface 230B. Thereafter, the film-forming process is completed by baking a film containing the conductive polymer and the low-surface energy material formed on the conductivity-controlling layer 220 to form a low-surface energy material concentration on the first surface 230A Control layer 230 gradually increasing in the direction from the first surface 230A toward the second surface 230B.

Since the work function-control layer 230 is formed by the self-organization of the conductive polymer and the low-surface energy material through a single solution film-forming process, The polymer layer and the low-surface energy material layer are separated from each other by a single layer.

The work function of the second surface 230B of the work function-control layer 230 may be equal to or greater than the work function of the conductive polymer, and the work function of the first surface 230A of the work function- The work function may be equal to or less than the work function of the low-surface energy material, but is not limited thereto.

The low-surface energy material may be a material having a solubility of at least 90%, such as at least 95%, for a polar solvent. Examples of the polar solvent include water, alcohols such as methanol, ethanol, n-propanol, 2-propanol, n-butanol, formic acid, nitromethane, acetaic acid, N-methyl-2-pyrrolidone, N-dimethylacetamide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) But are not limited to, tetrahydrofuran (THF), ethyl acetate (EtOAc), acetone, acetonitrile (MeCN), and the like.

The low-surface energy material may be at least one F-containing material. For example, the low-surface energy material may be a fluorinated polymer or fluorinated oligomer containing at least one F.

According to one embodiment, the low-surface energy material may be a fluorinated polymer having repeating units of any one of the following formulas:

≪ Formula 1 >

In Formula 1,

a is a number from 0 to 10,000,000;

b is a number from 1 to 10,000, 000;

Q ₁ is - [OC (R ₁ ) (R ₂ ) -C (R ₃ ) (R ₄ )] _c - [OCF ₂ CF ₂ ] _d -R ₅ , -COOH or -OR _f -R ₆ ;

R ₁ , R ₂ , R ₃ and R ₄ independently of one another are -F, -CF ₃ , -CHF ₂ or -CH ₂ F;

C and d are independently of each other a number from 0 to 20;

Wherein R _f is - (CF ₂ ) _z - (z is an integer from 1 to 50) or - (CF ₂ CF ₂ O) _z -CF ₂ CF ₂ - (z is an integer from 1 to 50);

R ₅ and R ₆ independently of one another are -SO ₃ M, -PO ₃ M ₂ or -CO ₂ M;

Wherein M is ^{Na +, K +, Li +} , H +, CH 3 (CH 2) w NH 3 + (w is an integer from 0 to ^{_{50), NH 4 +, NH}} 2 +, NHSO 2 CF 3 +, CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ , CH ₃ (CH ₂ ) _w CHO ⁺ (w is an integer from 0 to 50);

(2)

In Formula 2,

Q ₂ is hydrogen, a substituted or unsubstituted C ₅ -C ₆₀ aryl group or -COOH;

Q ₃ is hydrogen or a substituted or unsubstituted C ₁ -C ₂₀ alkyl group;

Q ₄ represents -O- (CF ₂ ) _r -SO ₃ M, -O- (CF ₂ ) _r -PO ₃ M ₂ , -O- (CF ₂ ) _r -CO ₂ M or -CO- CH ₂ ) _s - (CF ₂ ) _t -CF ₃ ,

R, s and t are independently of each other a number from 0 to 20;

Wherein M is ^{Na +, K +, Li +} , H +, CH 3 (CH 2) w NH 3 + (w is an integer from 0 to ^{_{50), NH 4 +, NH}} 2 +, NHSO 2 CF 3 +, CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ , CH ₃ (CH ₂ ) _w CHO ⁺ (w is an integer from 0 to 50);

(3)

In Formula 3,

m and n are 0 < m < 10,000,000 and 0 &lt; n &lt;

x and y are each independently a number from 0 to 20;

Y is -SO ₃ M, -PO ₃ M _2, or -CO ₂ M and;

Wherein M is ^{Na +, K +, Li +} , H +, CH 3 (CH 2) w NH 3 + (w is an integer from 0 to ^{_{50), NH 4 +, NH}} 2 +, NHSO 2 CF 3 +, CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ , CH ₃ (CH ₂ ) _w CHO ⁺ (w is an integer from 0 to 50);

For example, the low-surface energy material may be a fluorinated polymer including the repeating unit represented by the formula (1), but is not limited thereto.

For example, the low-surface energy material is a fluorinated polymer containing a repeating unit represented by the formula (1), a is a number of 100 to 10000, b is a number of 50 to 1000, Q ₁ is - [OC R &_lt; ₁ &gt;) (R ₂ ) -C (R ₃ ) (R ₄ )] _c - [OCF ₂ CF ₂ ] _d -R ₅ .

For example, the low-surface energy material is a fluorinated polymer containing the repeating unit represented by Formula 1, wherein a is a number of 100 to 10000, b is a weight of 50 to 1000, Q ₁ is - OC (R _{1) (R 2) -C (} R 3) (R 4)] c - [OCF 2 CF 2] d -R 5 being a fluoride gobunjayi, wherein c is a number from 1 to 3, R _1, R _2, and R ₃ is -F, R ₄ is -CF ₃ , d is a number from 1 to 3, and R ₅ is -SO ₃ M, but is not limited thereto.

The low-surface energy material may be a fluorinated silane-based material represented by the following formula (10)

&Lt; Formula 10 >

XM ^f _n -M ^h _m -M ^a _r - (G) _p

In the formula (10)

X is a terminal group;

M ^f represents a unit derived from a fluorinated monomer obtained from the condensation reaction of a perfluoropolyether alcohol, a polyisocyanate and an isocyanate-reactive non-fluorinated monomer, or a fluorinated C ₁ -C ₂₀ alkylene group;

M ^h represents a unit derived from a non-fluorinated monomer;

M ^a represents a unit having a silyl group represented by -Si (Y ₄ ) (Y ₅ ) (Y ₆ );

Y ₄ , Y ₅ and Y ₆ independently represent a halogen atom, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group or a hydrolyzable substituent, and Y ₄ , Y ₅ and Y ₆ is the hydrolyzable substituent;

G is a monovalent organic group containing a residue of a chain transfer agent;

n is a number from 1 to 100;

m is a number from 0 to 100;

r is a number from 0 to 100;

n + m + r is at least 2;

and p is a number of 0 to 10.

For example, X may be a halogen atom, M ^f may be a fluorinated C ₁ -C ₁₀ alkylene group, M ^h may be a C ₂ -C ₁₀ alkylene group, and Y ₄ , Y ₅ And Y &lt; ₆ &gt; independently of each other may be a halogen atom (Br, Cl, F, etc.), and p may be 0. For example, the fluorinated silane-based material represented by Formula 10 may be CF ₃ CH ₂ CH ₂ SiCl ₃ , but is not limited thereto.

A detailed description of the fluorinated silane-based material represented by Formula 10 is described in U.S. Patent No. 7728098, which is incorporated herein by reference.

For example, the conductive polymer may be a polythiophene, a polyaniline, a polypyrrole, a polystyrene, a sulfonated polystyrene, a poly (3,4-ethylenedioxythiophene), a self-doped conductive polymer, a derivative thereof, . The derivative may mean that it may further include various sulfonic acids and the like.

For example, the conductive polymer may be selected from the group consisting of Pani: DBSA (polyaniline / dodecylbenzenesulfonic acid: polyaniline / dodecylbenzenesulfonic acid, see Chemical Formula), PEDOT: PSS (poly (3,4-ethylenedioxythiophene) (Polyaniline / camphor sulfonicacid) or PANI: PSS (polyaniline) / poly (4-ethylenediaminetetrafluoroethylene) styrenesulfonate): polyaniline) / poly (4-styrenesulfonate)), and the like, but the present invention is not limited thereto.

                 Pani: DBSA PEDOT: PSS

The R may be H or a C1-C10 alkyl group.

The self-doped conducting polymer may have a degree of polymerization of 10 to 10,000,000 and may have a repeating unit represented by the following formula (100): &lt; EMI ID =

(100)

In the formula (100), 0 <m <10,000,000, 0 <n <10,000,000, 0? A? 20, 0? B?

At least one of R ₁ , R ₂ , R ₃ , R ' ₁ , R' ₂ , R ' ₃ and R' ₄ contains an ionic group; A, B, A 'and B' , Si, Ge, Sn, or Pb;

Wherein R ₁ , R ₂ , R ₃ , R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are each independently selected from the group consisting of hydrogen, halogen, nitro, substituted or unsubstituted amino, cyano, A substituted or unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₁ -C ₃₀ alkoxy group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C ₃₀ arylalkyl group, the unsubstituted C ₆ -C ₃₀ aryloxy group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group, a substituted or unsubstituted C ₂ -C ₃₀ ring C ₂ hetero aryloxy -C _30, a substituted or unsubstituted C ₅ -C ₃₀ of a cycloalkyl group, a substituted or unsubstituted C ₅ -C ₃₀ hetero cycloalkyl group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl ester group, and a substituted or is selected from the group consisting of a C ₆ aryl ring of the ester -C ₃₀ Beach, the carbon in the formula, and optionally hydrogen or to Gen element is coupled to;

R ₄ is a conjugated conductive polymer chain;

X and X 'are each independently a single bond, O, S, a substituted or unsubstituted C ₁ -C ₃₀ alkylene group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkylene group, a substituted or unsubstituted C ₆ Substituted or unsubstituted C ₆ -C ₃₀ arylalkylene group, substituted or unsubstituted C ₆ -C ₃₀ arylalkylene group, substituted or unsubstituted C ₂ -C ₃₀ heteroarylene group, substituted or unsubstituted C ₂ -C ₃₀ heteroarylalkyl a group, a substituted or non-substituted cycloalkyl group of the unsubstituted C ₅ -C _20, and substituted or carbon in the beach is selected from the group consisting of a heterocycloalkyl group of the aryl ester-substituted C ₅ -C _30, the formula, optionally Hydrogen or a halogen element may be bonded.

For example, the ionic group is _{^{PO 3 2 -, SO 3 -}} , COO -, I -, CH 3 COO - group and anion group Na ^+, selected from the consisting of ^{K +, Li +, Mg +2} , Zn +2 , And Al ⁺³ , and an organic ion selected from the group consisting of H ⁺ , NH ₄ ⁺ , CH ₃ (-CH ₂ -) _n O ⁺ (n is a natural number of 1 to 50) &Lt; / RTI &gt;

For example, at least one of R ₁ , R ₂ , R ₃ , R ' ₁ , R' ₂ , R ' ₃ and R' ₄ in the self-doped conducting polymer of Formula 100 is fluorine or is substituted with fluorine But is not limited thereto.

Specific examples of the conductive polymer include, but are not limited to, the following:

&Lt; Polymer 1 (PEDOT: PSS) > < Polymer 2 (PANI: DBSA) >

&Lt; Polymer 3 > < Polymer 4 (PSS-g-PANI) >

&Lt; Polymer 5 > < Polymer 6 >

<Polymer 7> <Polymer 8>

<Polymer 9 (PANI: PSS)> <Polymer 10>

&Lt; Polymer 11 > < Polymer 12 >

&Lt; Polymer 13 > < Polymer 14 >

&Lt; Polymer 15 > < Polymer 16 >

&Lt; Polymer 17 > < Polymer 18 >

&Lt; Polymer 19 > < Polymer 20 >

&Lt; Polymer 21 > < Polymer 22 >

&Lt; Polymer 23 > < Polymer 24 >

<Polymer 25>

Specific examples of the unsubstituted alkyl groups in the present specification include linear or branched alkyl groups such as methyl, ethyl, propyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl and hexyl. The at least one hydrogen atom contained may be substituted with at least one substituent selected from the group consisting of a halogen atom, a hydroxy group, a nitro group, a cyano group, a substituted or unsubstituted amino group (-NH ₂ , -NH (R), -N (R ' R "is independently an alkyl group having 1 to 10 carbon atoms with each other), an amidino group, hydrazine, hydrazone or jongi, a carboxyl group, a sulfonic acid group, phosphoric acid group, a halogenated alkyl group of C ₁ -C ₂₀ alkyl, C ₁ -C ₂₀ a, A C ₁ -C ₂₀ alkenyl group, a C ₁ -C ₂₀ alkynyl group, a C ₁ -C ₂₀ heteroalkyl group, a C ₆ -C ₂₀ aryl group, a C ₆ -C ₂₀ arylalkyl group, a C ₆ -C ₂₀ Or a C ₆ -C ₂₀ heteroarylalkyl group.

The heteroalkyl group in the present specification means that at least one, preferably 1 to 5 carbon atoms in the main chain of the alkyl group is substituted with a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom and the like.

Aryl groups in this specification refer to carbocyclic aromatic systems comprising at least one aromatic ring, which rings may be attached together or fused together by a pendant method. Specific examples of the aryl group include an aromatic group such as phenyl, naphthyl, tetrahydronaphthyl and the like, and at least one hydrogen atom of the aryl group may be substituted with the same substituent as the alkyl group.

As used herein, the heteroaryl group means a ring aromatic system having 5 to 30 ring atoms, with 1, 2 or 3 heteroatoms selected from N, O, P or S and the remaining ring atoms C, Or they can be fused together. And at least one hydrogen atom of the heteroaryl group may be substituted with the same substituent as the alkyl group.

The alkoxy group in the present specification refers to a radical -O-alkyl, wherein alkyl is as defined above. Specific examples include methoxy, ethoxy, propoxy, isobutyloxy, sec-butyloxy, pentyloxy, iso-amyloxy, hexyloxy and the like. At least one hydrogen atom of the alkoxy group May be substituted with the same substituent as the case.

If the group is a substituent of heterocyclic alkoxy used in the present invention contains one or more heteroatoms, for example, except that oxygen, sulfur or nitrogen may be present in the alkyl chain essentially has the meaning of said alkoxy, for example, CH ₃ CH ₂ OCH ₂ CH ₂ O-, C ₄ H ₉ OCH ₂ CH ₂ OCH ₂ CH ₂ O-, and CH ₃ O (CH ₂ CH ₂ O) _n H.

As used herein, an arylalkyl group means that in the aryl group as defined above, some of the hydrogen atoms are replaced by a radical such as lower alkyl, such as methyl, ethyl, propyl, and the like. For example, benzyl, phenylethyl and the like. At least one hydrogen atom of the arylalkyl group may be substituted with the same substituent as the alkyl group.

In the present specification, the heteroarylalkyl group means that a part of the hydrogen atoms of the heteroaryl group is substituted with a lower alkyl group, and the definition of heteroaryl in the heteroarylalkyl group is as described above. At least one hydrogen atom of the heteroarylalkyl group may be substituted with the same substituent as the alkyl group.

The aryloxy group in this specification refers to a radical -O-aryl, wherein aryl is as defined above. Specific examples thereof include phenoxy, naphthoxy, anthracenyloxy, phenanthrenyloxy, fluorenyloxy, indenyloxy and the like. At least one hydrogen atom of the aryloxy group may be substituted with the same substituent as the alkyl group Do.

The heteroaryloxy group in this specification refers to a radical -O-heteroaryl, wherein the heteroaryl is as defined above.

In the present specification, specific examples of the heteroaryloxy group include benzyloxy, phenylethyloxy and the like, and at least one hydrogen atom of the heteroaryloxy group may be substituted with the same substituent as the alkyl group.

In the present specification, the cycloalkyl group means a monovalent monocyclic system having 5 to 30 carbon atoms. At least one hydrogen atom in the cycloalkyl group may be substituted with a substituent similar to that of the alkyl group.

As used herein, a heterocycloalkyl group refers to a monovalent monocyclic system of 5 to 30 ring atoms, wherein the ring atom contains C, 1, 2 or 3 heteroatoms selected from N, O, P or S, At least one hydrogen atom of the cycloalkyl group may be substituted with the same substituent as the alkyl group.

In the present specification, the alkyl ester group means a functional group having an alkyl group and an ester group bonded thereto, wherein the alkyl group is as defined above.

In the present specification, a heteroalkyl ester group means a functional group having a heteroalkyl group and an ester group bonded thereto, and the heteroalkyl group is as defined above.

In the present specification, an aryl ester group means a functional group having an aryl group and an ester group bonded thereto, wherein the aryl group is as defined above.

In the present specification, the heteroaryl ester group means a functional group in which a heteroaryl group and an ester group are bonded, wherein the heteroaryl group is as defined above.

The amino group used in the present invention is -NH ₂ , -NH (R) or -N (R ') (R "), and R' and R" are independently an alkyl group having 1 to 10 carbon atoms.

In the present specification, halogen is fluorine, chlorine, bromine, iodine, or astatine, of which fluorine is particularly preferred.

The total concentration of the low-surface energy material in the work-function layer 230 of the first electrode 1, which is the high-work function and high-conductivity hybrid conductive thin film, is in the range of from 10 parts by weight to 500 parts per 100 parts by weight of the conductive polymer For example, 20 parts by weight to 400 parts by weight, but is not limited thereto. If the content of the low-surface energy material satisfies the above-described range, the work-function-control layer 230 can have a high work function on the second surface 230B.

The conductivity-controlling layer 220 serves to improve the conductivity, optical transparency, and mechanical strength of the first electrode 1.

The conductivity-control layer 220 is in contact with the first surface 230A of the work function-control layer 230. The conductivity-

The conductivity-controlling layer 220 may be formed of a conductive polymer, metal carbon nanotubes, graphene, reduced graphene oxide, metal nano-particles, or the like, which can replace the metal oxide electrode and have excellent bending stability. A metal grid, a semiconductor nanowire, and a metal nano dot, wherein the low-surface energy material is not included.

The conductive polymer that can be included in the conductivity-controlling layer 220 may be selected from among the conductive polymers included in the work function-controlling layer 230, but the present invention is not limited thereto.

The conductive polymer included in the conductivity-controlling layer 220 may be the same as or different from the conductive polymer contained in the work function-controlling layer 230.

According to one embodiment, the conductive polymer included in the conductivity-controlling layer 220 is the same as the conductive polymer included in the work-function-controlling layer 230.

The metallic carbon nanotube may be a purified metallic carbon nanotube itself or a carbon nanotube having metal particles (for example, Ag, Au, Cu, Pt particles, etc.) attached to the inner wall and / Lt; / RTI &gt;

The graphene may be a graphene monolayer having a thickness of about 0.34 nm, a few layer graphene having a laminated structure of 2 to 10 graphene monolayers, or a graphene single layer having a larger number of graphenes than the water- Layer may have a multi-layer structure of graphene having a laminated structure.

The metal nanowires and the semiconductor nanowires can be, for example, Ag, Au, Cu, Pt NiSi _x (Nickel Silicide) nanowires, and composites of two or more of the same, such as alloys or core- ) Structures, etc.) nanowires, but are not limited thereto.

Alternatively, the semiconductor nanowires may be Si nanowires doped with Si, Ge, B or N, Ge nanowires doped with B or N, and complexes of two or more of them (e.g., alloys or core-shell structures) But is not limited thereto.

The diameter of the metal nanowire and the semiconductor nanowire may be 5 nm to 100 nm or less and the length may be 500 nm to 100 μm depending on the method of manufacturing the metal nanowire and the semiconductor nanowire .

The metal grid may be formed of metal wires intersecting each other by using Ag, Au, Cu, Al, Pt, or an alloy thereof, and may have a line width of 100 nm to 100 탆, Do not. The metal grid may be formed to protrude from the substrate, or may be embedded in the substrate to form a recess.

The metal nano dots may be selected from Ag, Au, Cu, Pt, and nano dots of two or more complexes (for example, an alloy or a core-shell structure), but are not limited thereto.

The metal nanowires, the surface of the semiconductor nano-wire and nano-metal point, -S (Z ₁₀₀₎ and _{-Si (Z 101) (Z 102} ) at least one moiety represented by (Z ₁₀₃₎ (here, the Z _100, Z ₁₀₁ , Z ₁₀₂ and Z ₁₀₃ are independently of each other hydrogen, a halogen atom, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group or a substituted or unsubstituted C ₁ -C ₂₀ alkoxy group) . The -S (Z ₁₀₀₎ and _{-Si (Z 101) (Z 102} ) (Z 103) with at least one moiety represented a self-assembly (self-assembled) as a moiety, the metal nano via the moiety The bonding strength between the wire, the semiconductor nanowire and the metal nano dots, or the bonding force between the metal nanowire, the semiconductor nanowire, and the metal nano dots and the substrate 210 can be enhanced. As a result, It is possible to produce the first electrode 1 which is an improved high-work function and high-conductivity hybrid conductive thin film.

 The conductivity-control layer 220 can be a metal oxide electrode, i) a conductive polymer that is superior in bending stability, and ii) a metal-carbon nanotube, a graphene, a reduced graphene oxide ), Metal nanowires, metal grids, semiconductor nanowires, and metal nano dots. At this time, the conductivity-controlling layer 220 includes a conductive polymer as a matrix, and at least one of the metallic carbon nanotube, graphene, metal nanowire, semiconductor nanowire, and metal nano-dot is uniformly distributed over the matrix Or may be non-uniformly distributed in a specific region.

When the first electrode 1, which is a high-work function and high-conductivity hybrid conductive thin film, is used as a transparent electrode, the work function of the first electrode 1 as the high-work function and high- The thickness of layer 230 may be between 10 nm and 500 nm, for example between 20 and 200 nm. When the thickness of the work function-control layer 230 satisfies the above-described range, excellent work function characteristics, transmittance and flexible characteristics can be provided.

The conductivity of the first electrode 1, which is a high-work function and high-conductivity hybrid conductive thin film, is 1 S / cm or more (the thickness of the first electrode 1, which is the high-work function and high- Is 100 nm).

The first electrode 1, which is a high-work function and high-conductivity hybrid conductive thin film as described above, may be formed by forming a conductivity-control layer 220 on a substrate 210, By providing a mixture containing the conductive material, the low-surface energy material, and the first solvent on the substrate and then forming the work function-controlling layer 230 by heat treatment.

First, as the substrate 210, a substrate used in a conventional semiconductor process can be used. For example, the substrate may be a substrate, such as glass, sapphire, silicon, silicon oxide, metal foil (e.g., copper foil and aluminum foil), and a steel substrate (e.g., stainless steel) Metal oxides, polymer substrates, and combinations of two or more thereof. Examples of the metal oxide include aluminum oxide, molybdenum oxide, indium oxide, tin oxide, and indium tin oxide. Examples of the polymer substrate include a polytetrafluoroethylene (PTP), a polyethersulfone (PES) (PAR, polyacrylate), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethyleneterephthalate (PET), polyphenylene sulfide (PPS), polyarylate but are not limited to, polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propinonate (CAP).

For example, the substrate 210 may be a polymer substrate as described above, but is not limited thereto.

Then, a conductivity-control layer 220 is formed on the substrate 210.

According to one embodiment, on the substrate 210, a method such as a spin coating method, a casting method, a casting method, an amount Muray-Blodgett method (LB), an ink-jet printing method, such as nozzle printing, slot-die coating, doctor blade coating, screen printing, dip coating, gravure printing, Reverse-offset printing, physical transfer method, spray coating, chemical vapor deposition, thermal evaporation method, or the like, The conductivity-controlling layer can be formed by directly providing at least one of the conductive polymer, the metallic carbon nanotube, the graphene, the reduced oxidized graphene, the metal nanowire, the metal grid, the semiconductor nanowire and the metal nano dots.

According to another embodiment, the conductivity-controlling layer 220 comprises at least one of: i) a conductive polymer, a metallic carbon nanotube, graphene, reduced graphene, a metal nanowire, a semiconductor nanowire, and a metal nano- ), A mixture containing the second solvent is coated on the substrate, and the second solvent is removed by heat treatment. As an example of the second solvent, an example of a first solvent to be described later is referred to.

According to another embodiment, the conductive-control layer 220 may be formed by physically transferring the graphene sheet onto the substrate 210 when the conductive-control layer 220 may include graphene.

According to another embodiment, when the conductivity-controlling layer 220 includes metallic carbon nanotubes, the metallic carbon nanotubes may be grown on the substrate 210, or the carbon nanotubes dispersed in the solvent may be solution- For example, by a printing method (e.g., a spray coating method, a spin coating method, a dip coating method, a gravure coating method, a reverse offset coating method, a screen printing method, a slot-die coating method) .

According to another embodiment, when the conductivity-control layer 220 includes a metallic grid, a metal layer is formed on the substrate 210 by vacuum deposition of metal, and patterned in various mesh patterns by photolithography. (E.g., spray coating, spin coating, dip coating, gravure coating, reverse offset coating, screen printing, slot-die coating), or by dispersing a metal precursor or metal particles in a solvent The conductivity-control layer 220 can be formed.

Next, a mixture containing the conductive material, low-surface energy material and the first solvent as described above is provided on the conductivity-controlling layer 220. The description of the conductive material and low-surface energy material is given above. The first solvent is miscible with the conductive material and the low-surface energy material, and can be easily removed by heating or the like. The first solvent can be a polar solvent, for example, water, alcohols (methanol, ethanol, n-propanol, 2-propanol, n-butanol, etc.), formic acid, nitromethane, (N-methyl-2-pyrrolidone), N-dimethylacetamide (N-dimethylacetamide), dimethylformamide Dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), ethyl acetate (EtOAc), acetone, acetone, acetonitrile and the like. On the other hand, when selecting the first solvent, a co-solvent may be used. For example, as the first solvent, a mixture of water and an alcohol can be used. A polar organic solvent (e.g., DMSO, glycerol, ethylene glycol) other than water and alcohol may be further added to the mixture. Depending on the amount of the polar organic solvent added, the conductivity of the work function-controlling layer 230 can also be controlled. This may be because the polar organic solvent improves the aggregation and crystallization of the conductive polymer when it is present in an aqueous solution or an aqueous dispersion solution. The amount of the polar organic solvent to be added is usually from 1 to 30% by weight per 100% by weight of the first solvent.

The work function-control layer 230 may be formed, for example, not by forming the conductive polymer layer and the low-surface energy material layer separately but by forming the conductive polymer layer, the low-surface energy material and the first solvent (The surface energy difference between the conductive polymer and the low-surface energy material, which can be formed by a single film-forming process in which the mixture is provided on the conductivity-controlling layer 220 and then heat- So that each concentration gradient is formed), and the manufacturing process is simple. Therefore, by employing the high-work function and high-conductivity hybrid conductive thin film including the conductivity-control layer 220 and the work function-control layer 230 as described above as the first electrode 1, The device can be easily manufactured. In addition, since the high-work function and high-conductivity hybrid conductive thin film have flexible characteristics in contrast to the conventional ITO, if a flexible substrate is employed as the substrate 210 included in the organic solar cell, the flexible organic solar cell Can be implemented. As the flexible substrate, a polymer substrate as described above can be used, but the present invention is not limited thereto.

The photoactive layer 240 may include a material capable of separating holes and electrons from the irradiated light. For example, the photoactive layer 240 may include an electron donor and a hole acceptor. The photoactive layer 240 may have a variety of structures including a single layer including the electron donor and the hole acceptor or multiple layers including the layer including the electron donor and the layer including the hole acceptor .

The electron donor may include a p-type conductive high molecular material including a [pi] -electron. Examples of the electron donor include P3HT (poly (3-hexylthiophene), polysiloxane carbazole, polyaniline, polyethylene oxide, (poly (1-methoxy- Phenylene-vinylene), MEH-PPV (poly- [2-methoxy-5- (2'-ethoxyhexyloxy) - (2'-ethylhexyloxy) -1,4-phenylene vinylene], MDMO-PPV (poly [2-methoxy-5- (3 ', 7'-dimethyloctyloxy) Phenylene vinylene]), PFDTBT (poly (2,7- (9,9-dioctyl) -fluorene] poly ((2,7- (9,9-dioctyl) -2,5-dihydro- -fluorene-alt-5,5- (4 ', 7'-di-2-thienyl-2', 1 ', 3'- benzothiadiazole), PCPDTBT (poly [N'-O'-heptadecanyl- (4 ', 7'-di-2-thienyl-2', 1 ', 3'- benzothiazole), polyindole, polycarbazole, Diazine, polyisothianaphthalene, polyphenylene sulfide, polyvinylpyridine, polythiophene, polyphosphate Examples of the electron donor include, but are not limited to, rhenylene, polypyridine, CuPc (Copper Phthalocyanine), SubPc (subphthalocyanine), ClAlPc (Chloro-aluminum phthalocyanine) It is of course also possible to use combinations (including blends, copolymers, etc.).

Examples of the hole receptor include fullerenes having a high electron affinity (for example, C60, C70, C74, C76, C78, C82, C84, C720, C860, etc.); Fullerene derivatives (for example, PCBM ([6,6] -phenyl-C61 butyric acid methyl ester), C71-PCBM, C84-PCBM, bis-PCBM and the like); Perylene; Inorganic semiconductor containing nanocrystals such as CdS, CdTe, CdSe, ZnO and the like; Carbon nanotubes, carbon nanorods PBI (polybenzimidazole), PTCBI (3,4,9,10 perylenetetracarboxylic bisbenzimidazole), or mixtures thereof, but are not limited thereto.

For example, the photoactive layer 240 may be a single layer including P3HT as an electron donor and PCBM as a hole receptor, but is not limited thereto.

The photoactive layer 240 is irradiated with light, and excitons, which are pairs of electrons and holes, are formed by photoexcitation. The excitons act on the electrons and holes due to the difference in electron affinity between the electron donor and the hole acceptor at the interface between the electron donor and the hole acceptor. And is separated into holes.

The organic solar cell may not include a hole extraction buffer layer. A conventional hole extraction buffer layer formed from a conductive polymer composition such as poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) and polyaniline: poly (styrenesulfonate) The thin film conductivity is about 10 ^-6 S / cm to 10 ^-2 S / cm. For example, PEDOT: PSS of CLEVIOUS ^TM P VP AI4083 (Heraeous, formerly HC Starck) has a conductivity of 10 ^-3 S / cm, and CEDVIOUS ^TM VP VP CH8000 (Heraeous, formerly HC Starck) : PSS has a conductivity of 10 ^-6 S / cm. However, it is difficult to use PEDOT: PSS and PANI: PSS used in the conventional hole extraction buffer layer as an electrode material because the conductive polymer must have a conductivity of at least 0.1 S / cm or more in order to be used as an electrode material. The conductive polymer having a conductivity of 0.1 S / cm or more of the present invention is difficult to be used as a hole extraction buffer layer material. When the conductive polymer is used as a hole extraction buffer layer material, crosstalk between pixels of the organic light- As shown in FIG. Therefore, the conventional conductive polymer for forming the hole extraction buffer layer has been selected from among materials which have a conductivity of 10 ^-2 S / cm or less and have a work function higher than that of the conventional ITO to facilitate hole extraction. However, since the high-function electrode of the present invention may include a conventional hole extraction buffer layer, an additional hole extraction layer may not be required.

The electron transport region 250 may include an electron transport layer and an electron extraction layer. The electron transport layer serves to help transport electrons generated in the photoactive layer 240 to the second electrode 260.

The electron transport layer is preferably a quinoline derivative, particularly tris (8-hydroxyquinoline) aluminum: Alq ₃ , bis (2-methyl-8-quinolinolato) -4- Bis (10-hydroxybenzo [h] quinolinato) aluminum (Balq), bis (10-hydroxybenzo [h] quinolinato) quinolinato-beryllium: Bebq ₂ ), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) , 4,7-diphenyl-1,10-phenanthroline (Bphen), 2,2 ', 2 "- (benzene-1,3,5-tri ) - tris (1-phenyl-1H-benzimidazole: TPBI), (2,2 ', 2' 4- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,1- 2,4-triazole: TAZ), 4- (naphthalen-1-yl) -3,5-diphenyl-4H-1,2,4- -diphenyl-4H-1,2,4-triazole: NTAZ), 2, 9-bis (naphthalen-2-yl) -4,7-diphenyl-1,10-naphthalen-2-yl) -4,7-diphenyl-1,10-phenanthroline : NBphen), tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) 3TPYMB), phenyl-dipyrenylphosphine oxide (POPy2), 3,3 ', 5,5'-tetra [(m-pyridyl) 3 ', 5,5'-tetra [(m-pyridyl) -phen-3-yl] biphenyl: BP4mPy), 1,3,5-tri [ 1,3,5-tri [(3-pyridyl) -phen-3-yl] benzene: TmPyPB), 1,3- -bis [3,5-di (pyridin-3-yl) phenyl] benzene: BmPyPhB, bis (10- hydroxybenzo [h] quinolinato) beryllium: Bepq2), diphenylbis (4- (pyridin-3-yl) phenyl) silane DPPS and 1,3,5- Pyrid-3-yl-phenyl) benzene: TpPyPB), 1,3-bis [2- (2,2'- 6-yl) -1,3,4-oxadiazo-5-yl] benzene (1,3-bis [2- (2,2'-bipyridine- oxadiazo-5-yl] benzene: Bpy-OXD), 6,6'-bis [5- (biphenyl- (Biphenyl-4-yl) -1,3,4-oxadiazo-2-yl] -2,2'-bipyridyl: BP-OXD-Bpy) But is not limited thereto.

<Alq ₃ ><TPBI>

<PBD><BCP>

<Bphen> <Balq> <Bpy-OXD>

<BP-OXD-Bpy><TAZ>

<NTAZ><NBphen><3TPYMB>

<POPy2><BP4mPy><TmPyPB>

<BmPyPhB><Bepq2>

<Bebq2> <DPPS>

<TpPyPB>

The thickness of the electron transporting layer may be about 5 nm to 100 nm, for example, 15 nm to 60 nm. When the thickness of the electron transporting layer satisfies the above-described range, excellent electron transporting characteristics can be obtained without increasing the driving voltage.

The electron extraction layer may assist in transferring electrons generated in the photoactive layer 240 to the second electrode 260. Examples of the electron extraction layer material include, but are not limited to, LiF, NaCl, CsF, NaF, Li ₂ O, BaO, Cs ₂ CO ₃ and the like. The thickness of the electron injection layer may be from about 1 A to about 100 A, and from about 3 A to about 90 A. When the thickness of the electron injection layer satisfies the above-described range, satisfactory electron injection characteristics can be obtained without substantially increasing the driving voltage.

The electron injecting layer may contain LiF, NaCl, CsF, NaF, and Li _{2 in an amount} of 1 to 50% based on the electron transporting layer materials such as Alq ₃ , TAZ, Balq, Bebq ₂ , BCP, TBPI, TmPyPB, and TpPyPB. O, by including the metal derivative of BaO, Cs ₂ CO _3, the electron transport material, such as the _{Alq 3, TAZ, Balq, Bebq} 2, BCP, TBPI, TmPyPB, TpPyPB a metal such as Li, Ca, Cs, Mg And may be formed of a doped 1 nm to 100 nm thick layer

The photoactive layer 240 and the electron transport region 250 in the organic solar cell may be fabricated by a vacuum deposition and solution process. The vacuum deposition is usually performed by thermal evaporation and the solution process may be performed by spin coating, casting ink-jet printing, nozzle printing, spray coating, Screen printing, slot-die coating, doctor blade coating, dip coating, gravure printing, and offset printing (offset printing) printing method can be used.

The second electrode 260 may use a metal, an alloy, an electrically conductive compound, or a combination thereof having a relatively low work function. Specific examples thereof include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium- .

2 is a schematic cross-sectional view of an organic solar cell 200 'according to another embodiment.

The organic solar cell 200 'includes a substrate 201, a first electrode 210, a hole transport layer 235, a photoactive layer 240 as an active region for separating light into holes and electrons, an electron transport region 250, And a second electrode (260). The light incident on the photoactive layer 240 is separated into holes and electrons and the holes are transferred to the first electrode 210 via the hole transport layer 235. The electrons are transported through the electron transport region 250 Two electrodes 260 are formed.

A description of the substrate 201, the first electrode 210, the photoactive layer 240, the electron transport region 250, and the cathode 260 of the organic solar cell 200 'will be described with reference to FIG.

The hole transport layer 235 of the organic solar cell 200 'promotes the movement of holes from the photoactive layer 240 to the first electrode 210.

The material of the hole transporting layer 235 may be a material having a hole mobility higher than the electron mobility under the same electric field. The hole transport layer 235 may be formed using a known hole transport material, for example, an amine-based material having an aromatic condensed ring, or a triphenylamine-based material.

More specifically, the hole-transporting material may be at least one selected from the group consisting of 1,3-bis (carbazol-9-yl) benzene (MCP), 1,3,5- (Carbazol-9-yl) benzene: TCP), 4,4 ', 4 "-tris (carbazol-9-yl) triphenylamine Carbazole-9-yl) triphenylamine (TCTA), 4,4'-bis ) biphenyl (CBP), N, N'-bis (naphthalen-1-yl) -N, N'- bis (phenyl) -benzidine: NPB), N, N'-bis (naphthalen-2-yl) -N, N'- N, N'-bis (phenyl) -benzidine:? -NPB), N, N'-bis (naphthalen- , N'-bis (phenyl) -2,2'-dimethylbenzidine:? -NPD),

N, N ', N'-diphenyl-cyclohexane: TAPC), di- [4- (N, N -ditolylamino) N'-tetra-naphthalen-2-yl-benzidine:? - TNB) and N4, N4, N4 ', N4'-tetra (9,9-dioctylfluorene-co-bis-N, N '- (4-butylphenyl) -bis-N, N'-phenyl (4-butylphenyl) diphenylamine (TFB), poly (9,9'-dioctylfluorene-co-bis-N, N'- (4-butylphenyl) -bis-N, N'-phenylbenzidine (BFB), poly (9,9-dioctylfluorene-co- '-phenyl-1,4-phenylenediamine (PFMO), and the like can be used. However, it is not limited.

<NPB><MCP><TCP>

<TCTA><CBP>

< beta-NPB >< alpha -NPD >< TAPC &

<β-TNB> <TPD15>

Although the organic solar battery has been described with reference to FIGS. 1 and 2, the present invention is not limited thereto. For example, the second electrode 260 may be a high-work function and high-conductivity hybrid conductive thin film as described above. At this time, the second electrode 260 serves as a cathode, and the work function-control layer 220 can be positioned between the conductivity-control layer 230 and the photoactive layer 240, It is possible.

According to another embodiment, the work function-control layer 230 of the high-work function and high-conductivity hybrid conductive thin film 1 may contain a conductive polymer and a low-surface energy material as described above, A metal nanowire, a metal carbon nanotube, a semiconductor quantum dot, a semiconductor nanowire, and a metal nano-dot. By the additive, the conductivity of the high-work function and high-conductivity hybrid-conductive thin film 1 can be further improved.

[Example]

Example  One: Work function - Control layer  Production (I)

(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) solution (the content of PSS per 1 part by weight of PH500 / PEDOT from HC Starck was 2.5 parts by weight The polymer 100 was dispersed in 5% by weight in a solution of the following polymer 100 (a mixture of water and alcohol (water: alcohol = 4.5: 5.5 (v / v)), Aldrich Co Ltd.) and 5% by weight of dimethyl sulfoxide (DMSO). Here, the mixing ratio of the PEDOT: PSS solution and the solution of the polymer 100 was adjusted so that the content (based on solid content) of the polymer 100 per 1 part by weight of PEDOT was 1.0 part by weight.

<Polymer 100>

(Of the polymer 100, x = 1300, y = 200, z = 1)

The mixture was spin-coated on a PET substrate and then heat-treated at 200 ° C for 10 minutes to form a work function-control layer 1 having a thickness of 100 nm. The conductivity of the work function-control layer 1 was 125 S / cm (measured with a 4-point probe).

The mixing ratio of the solution of the PEDOT: PSS solution to the solution of the polymer 100 was adjusted to 2.3 parts by weight, 4.9 parts by weight and 11.2 parts by weight of the polymer 100 per 1 part by weight of PEDOT, Control layers 2, 3, and 4 (the work function-control layers 1 to 4) were formed on the PET substrate using the same method as the manufacturing method of the work function-control layer 1, And the surface facing the first surface is the second surface, respectively.

Conductivities of the work function-control layers 2, 3 and 4 were 75 S / cm, 61 S / cm, and 50 S / cm, respectively (measured with a 4-point probe).

Comparative Example  A

The production method of the work function-control layer 1 was repeated except that the thin film was formed with a mixture of PEDOT: PSS (PH500 of HC Starck Co.) and 5 wt% of DMSO without the solution of the polymer 100 The electrode A was prepared using the same method.

Evaluation example  One: Work function - Control layer  evaluation

<Evaluation of molecular distribution by work function-control layer depth>

In order to examine the molecular distribution of the work function-control layers 1 to 4 and the surface (i.e., the second surface) of the electrode A, X-ray photoelectron spectroscopy (XPS, Is VG Scientific, and the model name is ESCALAB 220iXL). The results are shown in Table 1. In particular, the XPS spectrum of the work function-control layer 4 by sputter time (i.e., work function-control layer 4 depth) is shown in FIG. The PEDOT (164.5 eV) peak, the PSS and PSSH (168.4 and 168.9 eV) peaks (S2p) and the peak (CF ₂ , F1s) for the polymer 100 among the XPS spectra for each work function-control layer were analyzed, Was evaluated.

3, along the direction toward the first face of the work function-control layer 4 in the second face (sputter time = 0 second) of the work function-control layer 4, the CF ₂ moiety representing the concentration of the polymer 100 The concentration is substantially reduced, and the concentration of PEDOT is substantially increased. Therefore, it can be seen that the concentration of the PEDOT: PSS and the polymer 100 in the work function-controlling layer 4 has a gradient varying with the depth of the work function-controlling layer 4. [

 Table 1 summarizes the fluorine / PSS ratios of the second surface calculated from the PSS peak S2p and the fluorine peak (F1s) area of the second surface of the work function-control layers 1 to 4, It can be seen that as the amount of polymer 100 used increases in the function-control layer formation, the proportion of the polymer 100 in the work function-control layer surface (ie, the second surface) increases:

PEDOT / PSS / Polymer 100
(Weight ratio) PSS peak area Fluorine peak area Fluorine / PSS ratio Work function - control layer 4 1 / 2.5 / 11.2 220.0718 3571.604 8.764 Work function - control layer 3 1 / 2.5 / 4.9 508.1833 7793.913 8.282 Work function - Control layer 2 1 / 2.5 / 2.3 412.4424 4589.502 6.001 Work function - control layer 1 1 / 2.5 / 1.0 696.8955 7118.15 5.516 Electrode A 1 / 2.5 / 0 311.484 0 -

<Work function - Evaluation of work function and conductivity of the control layer>

The work function is evaluated using the ultraviolet photoelectron spectroscopy in air (manufacturer is Nikken Keiki, model name is AC2) for the work function-control layers 1 to 4 and the electrode A, The results are shown in Table 2.

PEDOT / PSS / Polymer 100
(Weight ratio) The work function (eV) Conductivity (S / cm) Electrode A 1 / 2.5 / 0 4.73 300 Work function - control layer 1 1 / 2.5 / 1.0 5.07 125 Work function - Control layer 2 1 / 2.5 / 2.3 5.23 75 Work function - control layer 3 1 / 2.5 / 4.9 5.64 61 Work function - control layer 4 1 / 2.5 / 11.2 5.80 50

Since the work function is evaluated for the work function-control layers 1 to 4 and the electrode A formed on the PET substrate, the work function of Table 2 is interpreted as a work function of the second face of the work function-control layers 1 to 4 .

It can be seen that the conductivity is decreased as the weight ratio of the polymer 100 is increased. This can be interpreted as the polymer 100 is an insulator.

<Evaluation of hole injection efficiency of work function-control layer>

The hole injection efficiencies of the work function-control layers 1 to 4 were evaluated, and the results are shown in Fig. 4, respectively. In the evaluation of hole injection efficiency, DI SCLC (dark injection space-charge-limited-current) measurement method was used, which has a structure of work function-control layer 1, 2, 3 and 4 / NPB layer After the hole-electron device was fabricated, the DI SCLC transition evaluation was performed. A pulse generator (HP 214B) and a digital oscilloscope (Agilent Infiniium 54832B) were used for the dark injection space-charge-limited-current (DI SCLC) transition evaluation. From FIG. 4, it can be seen that the work function-control layers 1 to 4 have excellent hole mobility and hole injection efficiency.

Example 2: Electrode Fabrication (I) (Conductivity - High- Work Function and High-Conductivity Hybrid Using Conductive Polymer as Control Layer Preparation of Conductive Thin Film)

(3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) (PH1000 of HC Starck, PSS content per 1 part by weight of PEDOT was 2.5 parts by weight / 0.3 S / cm conductivity, better than PH500.) The mixture was spin-coated with 5 wt% DMSO and heat-treated for 10 min at 200 ° C to form a 100-nm-thick conductivity-control layer Gt; S / cm &lt; / RTI &gt; conductivity at the time of measurement).

By forming the work function-control layers 1, 2, 3 and 4 respectively on the conductivity-control layer in the same manner as in the method described in Example 1, four kinds of high-work function and high-conductivity hybrid- . These were named electrode 1, electrode 2, electrode 3 and electrode 4 in that order.

Comparative Example  B

Except that the electrode was formed of a mixture containing PEDOT: PSS (PH1000 of HC Starck Co.) and 5 wt% of DMSO, without using the solution of the polymer 100, To prepare an electrode B.

Evaluation example  2: Electrode evaluation (I)

&Lt; Evaluation of Electrode Conductivity &

Tables 3 and 4 compare the conductivity of each electrode. Table 3 shows that the electrode (electrode A) manufactured using the PH500 has higher conductivity than the electrode (electrode B) manufactured using the PH1000. It can be seen from Table 4 that the electrodes (electrodes 1 to 4) including the conductivity-control layer show better conductivity than the work function-control layer (work function-control layers 1 to 4).

Conductivity (S / cm) Electrode A 300 Electrode B 600

Work function - control layer 1 Electrode 1 Work function - Control layer 2 Electrode 2 Work function - control layer 3 Electrode 3 Work function - control layer 3 Electrode 4 Conductivity (S / cm) 125 540 75 500 61 460 50 410

Example  3: OPV Production

After forming the electrode 1 as an anode on the glass substrate according to the second embodiment, an 80 nm thick PCDTBT: PC70BM photoactive layer, a 1 nm thick Ca electron extraction layer and a 100 nm thick Al And a cathode were successively formed (using the vacuum evaporation method) to prepare OPV 1.

Comparative Example  One

OPV A was prepared using the same method as in Example 3 except that the electrode A of Comparative Example A was used instead of the electrode 1.

Comparative Example  2

OPV B was fabricated in the same manner as in Example 3, except that only the work function-control layer 1 of Example 1 was formed instead of the electrode 1.

Comparative Example  3

The upper (15Ω / ㎠ (1200Å) ITO glass substrate of Corning Incorporated (Corning)) ITO electrode PEDOT: PSS solution ^{(CLEVIOS TM P VP AI4083 / PEDOT} 1 parts by weight per PSS is 6 parts by weight) was spin-coated, 200 ℃ For 10 minutes to form a 30 nm thick PEDOT: PSS hole extraction layer. A PCDTBT: PC70BM photoactive layer with a thickness of 80 nm, a Ca electron extraction layer with a thickness of 1 nm, and an Al cathode with a thickness of 100 nm were sequentially formed on the hole injection layer (using the vacuum deposition method).

Evaluation example  3: OPV  evaluation

(PCE), short-circuit current (J _SC ), open-circuit voltage (V _OC ), and fill factor (FF) for OPV 1 and OPV A to C using a Keithley 2400 source measuring instrument, Newport 69907 power supply and digital exposure controller operation ) Were evaluated. The results are shown in Table 5 and FIG. From Table 5 and FIG. 5, it can be seen that OPV 1 shows excellent fill factor (FF) and efficiency (PCE) as compared with OPV A to C.

OPVA OPV B OPV C OPV 1 Fitted V _OC (V) 0.838 0.878 0.856 0.846 Fitted J _SC (mA / cm 2) 10.4 12.5 10.9 10.8 FF (%) 47.0 51.2 57.4 61.0 PCE (%) 4.1 5.5 5.5 5.6 R _shunt (Ω cm ² ) 405.8 649.2 1002.9 762.8 R _series (Ω cm ² ) 29.2 20.8 8.8 13.1

210: substrate
1: First electrode (high-work function and high-conductivity hybrid conductive thin film)
220: Conductivity - control layer
230: work function - control layer
230A: a first side of work function-control layer 230
230B: the second side of work function-control layer 230
235: hole transport layer
240: photoactive layer
250: electron transport region
260: second electrode

Claims (13)

Board; A first electrode; A second electrode; And a photoactive layer disposed between the first electrode and the second electrode,
Wherein at least one of the first electrode and the second electrode comprises:
And a second surface opposite the first surface, wherein the concentration of the low-surface energy material in the second surface is greater than the concentration of the low-surface energy material in the second surface, Surface energy material of the first side, a work function of the second side of 5.0 eV or more, and a work function-tuning layer; And
A conductivity-tuning layer comprising a conductive polymer, wherein the conductivity-tuning layer does not comprise the low-surface energy material and is in contact with a first side of the work function-controlling layer;
And a hybrid conductive thin film having a conductivity of at least 1 S / cm, including a high work function and a high conductivity,
Wherein the second side of the work function-control layer faces the photoactive layer. The method according to claim 1,
Wherein the first electrode is the high-work function and high-conductivity hybrid conductive thin film,
The first electrode serves as an anode,
Wherein the work function-control layer is interposed between the substrate and the photoactive layer. The method according to claim 1,
Wherein the concentration of the low-surface energy material gradually increases from the first side to the second side. The method according to claim 1,
Wherein the low-surface energy material is a fluorinated material comprising at least one F. The method according to claim 1,
Wherein the low-surface energy material is a fluorinated polymer having a repeating unit represented by any of the following formulas (1) to (3).
&Lt; Formula 1 >

In Formula 1,
a is a number from 0 to 10,000,000;
b is a number from 1 to 10,000, 000;
Q_One- [O-C (R_One) (R₂) -C (R₃) (R₄)]_c- [OCF₂CF₂]_d-R₅, -COOH, or -O-R_f-R₆ego;
The R_One, R₂, R₃ And R₄Independently of one another are -F, -CF₃, -CHF₂ Or -CH₂F;
C and d are independently of each other a number from 0 to 20;
The R_f- (CF₂)_z- (z is an integer from 1 to 50) or - (CF₂CF₂O)_z-CF₂CF₂- (z is an integer from 1 to 50);
The R₅ And R₆Independently of one another, -SO₃M, -PO₃M₂ Or -CO₂M;
Wherein M is Na⁺, K⁺, Li⁺, H⁺, CH₃(CH₂)_wNH₃ ⁺(w is an integer from 0 to 50), NH₄ ⁺, NH₂ ⁺, NHSO₂CF₃ ⁺, CHO⁺, C₂H₅OH⁺, CH₃OH⁺, CH₃(CH₂)_wCHO⁺ (w is an integer from 0 to 50);
(2)

In Formula 2,
Q₂Is hydrogen, substituted or unsubstituted C₅-C₆₀An aryl group or -COOH;
Q₃Is hydrogen or a substituted or unsubstituted C_One-C₂₀Alkyl group;
Q₄Is -O- (CF₂)_r-SO₃M, -O- (CF₂)_r-PO₃M₂, -O- (CF₂)_r-CO₂M, or -CO-NH- (CH₂)_s- (CF₂)_t-CF₃ego,
R, s and t are independently of each other a number from 0 to 20;
Wherein M is Na⁺, K⁺, Li⁺, H⁺, CH₃(CH₂)_wNH₃ ⁺(w is an integer from 0 to 50), NH₄ ⁺, NH₂ ⁺, NHSO₂CF₃ ⁺, CHO⁺, C₂H₅OH⁺, CH₃OH⁺, CH₃(CH₂)_wCHO⁺ (w is an integer from 0 to 50);
(3)

In Formula 3,
m and n are 0 < m < 10,000,000 and 0 &lt; n &lt;
x and y are each independently a number from 0 to 20;
Y is -SO₃M, -PO₃M₂ Or -CO₂M;
Wherein M is Na⁺, K⁺, Li⁺, H⁺, CH₃(CH₂)_wNH₃ ⁺(w is an integer from 0 to 50), NH₄ ⁺, NH₂ ⁺, NHSO₂CF₃ ⁺, CHO⁺, C₂H₅OH⁺, CH₃OH⁺, CH₃(CH₂)_wCHO⁺ (w is an integer of 0 to 50). The method according to claim 1,
Wherein the low-surface energy material is a fluorinated oligomer represented by the following Chemical Formula 10:
&Lt; Formula 10 >
XM ^f _n -M ^h _m -M ^a _r - (G) _p
In the formula (10)
X is a terminal group;
M ^f is a perfluoropolyether alcohol, a polyisocyanate and an isocyanate reactive non-fluorinated one screen unit derived from a fluorinated monomer or fluorinated monomer obtained from the condensation reaction of C ₁ - ₂₀ alkylene group;
M ^h represents a unit derived from a non-fluorinated monomer;
M ^a represents a unit having a silyl group represented by -Si (Y ₄ ) (Y ₅ ) (Y ₆ );
Y ₄ , Y ₅ and Y ₆ independently represent a halogen atom, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group or a hydrolyzable substituent, and Y ₄ , Y ₅ and Y ₆ is the hydrolyzable substituent;
G is a monovalent organic group containing a residue of a chain transfer agent;
n is a number from 1 to 100;
m is a number from 0 to 100;
r is a number from 0 to 100;
n + m + r is at least 2;
and p is a number of 0 to 10. The method according to claim 1,
Wherein the conductive polymer is selected from the group consisting of polythiophenes, polyanilines, polypyrroles, polystyrenes, sulfonated polystyrenes, poly (3,4-ethylenedioxythiophenes), self-doped conducting polymers, derivatives thereof, battery. delete The method according to claim 1,
Wherein the work function of the work function-control layer is selected in the range of 5.0 eV to 6.5 eV. The method according to claim 1,
Wherein the conductivity-controlling layer comprises a conductive polymer, and the conductive polymer contained in the conductivity-controlling layer is the same as the conductive polymer contained in the work-function-controlling layer. The method according to claim 1,
And a second side of the work function-control layer is in contact with the photoactive layer. The method according to claim 1,
Wherein the work function-control layer is at least one selected from the group consisting of carbon nanotubes, graphenes, reduced graphene, metal nanowires, metal carbon nanotubes, semiconductor quantum dots, semiconductor nanowires, Organic solar cell further containing additives. The method according to claim 1,
Wherein the photoactive layer has an ionization potential that is larger than the work function of the untreated indium tin oxide by 0.3 eV or more.

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