KR20100099502A - Display comprising an organic molecule solar cell - Google Patents

Abstract

PURPOSE: A display device with a solar battery in order to improve the efficiency of the light source is provided to supply the solar battery using an organic compound easy to manufacture and improve the efficiency of light source. CONSTITUTION: An organic molecule type solar battery(5) is embedded in a backlight unit. The organic molecule type solar battery is embedded in the rear of the light source of the backlight unit. The organic molecule type solar battery includes a reflective electrode. The organic molecule type solar battery is formed in a wet deposition process.

Description

DISPLAY COMPRISING AN ORGANIC MOLECULE SOLAR CELL}

The present invention relates to a display device having an organic molecular solar cell in which an organic molecular solar cell is applied to convert light leaked from a light source of a backlight unit into electrical energy, thereby storing or reflecting the electrical energy to efficiently utilize the leakage light source.

Display devices such as liquid crystal displays (LCDs), organic electroluminescent displays (OLEDs), electroluminescent displays (LEDs), plasma display panels (PDPs), and field emission displays (FEDs), control the amount of light from the outside. As a light receiving device for displaying an image, a backlight light source, which is a separate light source for irradiating light, is indispensable, and is particularly used in a non-light emitting image display device.

Such a backlight light source is classified into an edge type and a direct type according to the position of the light source with respect to the display surface. The edge type is a light source installed at the outside of the light guide plate, and the light emitted from the light source is incident on the entire surface of the panel by using a transparent light guide plate. The edge type is mainly used in small liquid crystal display devices such as laptops. It is widely used in large display devices of 30 inches or more because the light utilization is high, the handling is simple, and the size of the display surface is not limited because the light source is placed directly on the rear surface of the panel.

However, 100% of the characteristics of the backlight light source are not used, and only the light source which is almost lost and the front side of the back light is used. To improve this, the display device of the edge type (Korean Patent Publication Nos. 2001-0091505, 2002-0055996) and the direct type (Korean Patent Publication Nos. 2000-0073646, 2002-0067232, and 2005-0000957) Although the reflector is disposed on the back of the backlight light source and reflects light and sends it to the front, there is a disadvantage in that the inefficiency of the light source appears due to the diffuse reflection of the light when reflecting the light by the reflector.

In order to improve the inefficiency of the light source, a method of disposing a solar cell on the back of the backlight light source (Japanese Patent Publication No. 1990-29623, Korean Patent Publication No. 2007-0041033, 2008-0058764, and Korean Patent Registration No. 750068) ) Is presented. This method can be used as a power source of the display device by converting the backlight light source emitted to the back of the light source into electrical energy. However, the methods proposed to date use crystalline, amorphous silicon solar cells, inorganic solar cells and dye-sensitized solar cells as solar cells, and the crystalline solar cells are difficult to thin; Amorphous silicon solar cells and inorganic solar cells are advantageous in thin film formation, but the film forming process is complicated, film formation and enlargement is difficult, and expensive film forming equipment can increase the manufacturing cost. In addition, the dye-sensitized solar cell has a problem of leakage of liquid when the electrolyte type is necessarily used, and a problem of deterioration of energy conversion efficiency due to the slowing of the movement of the redox species in the polymer type.

The present invention relates to the economics, stability of use, manufacturing process efficiency and energy conversion efficiency of conventional crystalline silicon solar cells, amorphous silicon solar cells, inorganic solar cells and dye-sensitized solar cells used to improve the efficiency of the backlight light source. I want to improve.

In addition, the present invention is to provide a display device incorporating an organic-molecule-type solar cell, which is an electronic device using an organic compound that is various, inexpensive and easy to process compared to the prior art.

The present invention is characterized by a display device including a backlight unit having an organic molecular solar cell. In detail, the present invention applies an organic molecular solar cell to the back or side of the light source of the backlight unit to convert the light leaked from the light source into electrical energy to store electricity or to reflect and recycle the leaked light to efficiently utilize energy It is about.

The display device of the present invention employs an organic-molecule-type solar cell, which is an electronic device using an organic compound, which is various, inexpensive, and easy to process, compared to the prior art, and thus, economical efficiency and process efficiency of the display device are expected.

In addition, the display device may power the light leaking from the light source of the backlight unit using an organic molecular solar cell, and cover a portion of the power consumption of the display device with the power stored by the solar cell, By transferring a part of the leaked light is expected to improve the utilization efficiency of the light source, it is expected to reduce the power consumption applied through the external power source.

The present invention relates to a display device in which an organic molecular solar cell is embedded to convert and reflect light leaked from a light source of a backlight unit into electrical energy, thereby recycling the leaked light source. In this case, the display device includes a backlight unit such as a liquid crystal display (LCD), an organic electroluminescent display (OLED), an electroluminescent display (LED), a plasma display panel (PDP), a field emission display (FED), It can be used for the display device to which the BLU) is applied. The organic molecular solar cell of the present invention refers to an organic solar cell excluding a dye-sensitized solar cell among organic solar cells.

The light source of the backlight unit is generally used in the art and is not particularly limited, but specifically, a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), an external electrode fluorescent lamp (EEFL), and a surface light source (FFL) , A composite ceramic light source (CEFL) and a light emitting diode (LED) may be selected from the group consisting of. The backlight unit is divided into an edge type and a direct type according to the position of the light source with respect to the display surface, and thus the present invention is not limited by the position of the light source.

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

1 is a schematic cross-sectional view of one side of a direct type liquid crystal display device having a transmissive organic molecular solar cell according to the present invention. The liquid crystal display of FIG. 1 has a structure in which an organic molecular solar cell 5 for converting light into electrical energy is applied to the back of the backlight light source 4. The upper part of the backlight light source 4 is provided with a diffusion plate 3 for diffusing light, and a plurality of optical sheets 2 for improving brightness and viewing angle of the light diffused on the diffusion plate 3. The rear surface of the organic molecular solar cell 5 is composed of a backlight light source 4 and a reflector plate 6 of white or silver sheet which serves to reflect light leaked from the organic molecular solar cell 5. An upper portion of the optical sheet 2 is provided with a liquid crystal panel 1 including two substrates on which the field generating electrodes face each other, and a liquid crystal layer interposed therebetween.

2 is a schematic cross-sectional view of one side of a direct type liquid crystal display device incorporating a reflective organic molecular solar cell according to the present invention. The liquid crystal display of FIG. 2 has a structure in which an organic molecular solar cell 5 for converting light into electrical energy is applied to the backside of the backlight light source 4. The upper part of the backlight light source 4 is provided with a diffuser plate 3 for diffusing light and a plurality of optical sheets 2 disposed on the diffuser plate 3 and improving the brightness and viewing angle of the diffused light. In addition, the reflective organic molecular solar cell 5 also serves as a reflector for reflecting light leaked from the backlight light source 4. An upper portion of the optical sheet 2 is provided with a liquid crystal panel 1 including two substrates on which the field generating electrodes face each other, and a liquid crystal layer interposed therebetween.

3 is a schematic cross-sectional view of one side of an edge type liquid crystal display device having a transmissive organic molecular solar cell according to the present invention. The liquid crystal display of FIG. 3 has a structure in which an organic molecular solar cell 5 for converting light into electrical energy is applied to the rear and side surfaces of the backlight light source 4. A light guide plate 8 capable of transferring light is formed on the side surface of the backlight light source 4, and a diffusion sheet 7 diffuses light on the light guide plate 8 and a diffusion sheet 7 is formed on the diffusion sheet 7 and diffused. A plurality of optical sheets 2 which serve to improve the brightness and viewing angle of the emitted light are provided. The transmissive organic molecular solar cell 5 has a back light source 4 and a reflector plate 6 of white or silver sheet which serves to reflect light leaked from the solar cell 5. An upper portion of the optical sheet 2 is provided with a liquid crystal panel 1 including two substrates on which the field generating electrodes face each other, and a liquid crystal layer interposed therebetween.

4 is a schematic cross-sectional view of one side of an edge type liquid crystal display device incorporating a reflective organic molecular solar cell according to the present invention. The liquid crystal display of FIG. 4 has a structure in which an organic molecular solar cell 5 for converting light into electrical energy is applied to the rear and side surfaces of the backlight light source 4. A light guide plate 8 capable of transferring light is formed on the side of the backlight light source 4, and a light diffusion plate 7 diffuses light on the light guide plate 8 and an upper portion of the light diffusion plate 7. A plurality of optical sheets 2 are provided to improve the brightness and viewing angle of the diffused light, and the reflective organic molecular solar cell 5 serves as a reflector to reflect the light leaked from the backlight light source 4. Is also being performed at the same time. An upper portion of the optical sheet 2 is provided with a liquid crystal panel 1 including two substrates on which the field generating electrodes face each other, and a liquid crystal layer interposed therebetween.

On the other hand, the organic molecular solar cell embedded in the display device of the present invention is generally used in the art, the basic structure is a metal / organic conductor (photoactive layer) / metal structure of a transparent electrode having a high work function as an anode, A metal having a low work function is used as the cathode. In this case, both the upper and lower electrodes may be transparent electrodes, or the upper or lower electrodes may be reflective electrodes. When the reflective electrode is built, the reflective plate may reflect the light leaked from the light source of the backlight unit.

The photoactive layer may use a multi-layer structure in which donors (electron donor material, donor) and acceptor (electron acceptor material, acceptor) are stacked, or a single layer (bulk-heterojunction) structure in which they are mixed, and in some cases, a donor layer It is possible to use a mixed structure in which a bulk-heterojunction structure in which a donor-receptor is mixed between and a receptor layer is sandwiched. In addition, a hole transport layer may be interposed between the anode electrode and the photoactive layer as a buffer layer, and an electron transport layer may be interposed between the cathode and the photoactive layer. At this time, the material used as the photoactive layer should have excellent electrical properties such as charge mobility if the light absorption wavelength range should be well matched with the solar spectrum and have a very strong light absorption. Receptors must meet the prerequisite of having a higher electron affinity compared to the donor, but donor and acceptor material may change in relative terms.

In addition, organic semiconductors used as photoactive layers include organic monomolecules and polymers. In the case of organic monomolecules, there is a method using a vacuum deposition process in which a donor layer and an acceptor layer are formed continuously or simultaneously by heating in a vacuum. In this case, the solution in which the donor and acceptor are dissolved together is spin coated, ink-jet coated, screen printing, doctor blade, slit coating, The film is formed using a wet process such as flow coating, roll-to-roll coating, or the like. Recently, the mixed structure layer is arranged in a so-called tandem structure of two upper and lower layers to form a film.

The organic molecular solar cell is built in the rear or side of the light source of the backlight unit.

The display device according to the present invention is used with a built-in driving unit, which is a power supply, which is generally used in the art and is not particularly limited. The driving unit may be used when the power source obtained from the organic molecular solar cell is applied to the display device or when the power source obtained from the organic molecular solar cell is stored. In this case, the organic molecular solar cell covers a part of the total power consumption. It can also serve as an auxiliary power supply.

Hereinafter, the organic molecular solar cell of the present invention will be described in detail with reference to the following drawings.

5 is a schematic cross-sectional view of one side of a transmissive organic molecular solar cell according to the present invention. As shown in FIG. 5 (a), the backlight light source is incident through the transparent first electrode 9 to pass through the organic molecular solar cell layer 10 and the transparent second electrode 11 to be disposed on the rear surface of the second electrode 11. The reflective plate 6 is recycled as a backlight light source or used as a light source of the organic molecular solar cell layer 10. Alternatively, the laminated structure may be opposed as shown in FIG. 5 (b).

In this case, the first electrode 9 may include metal oxides such as transparent indium tin oxide (ITO), indium zinc oxide (IZO), fluorine-containing tin oxide (FTO), tin oxide, zinc oxide, and zinc aluminum oxide; And metal nitrides such as titanium nitride; Conductive polymers such as polyaniline, polythiopine, polypyrrole, polyphenylenevinylene, poly (3-methylthiopine) and polyphenylene sulfide can be used. As the second electrode 11, a metal such as gold, platinum, silver, copper, aluminum, nickel, cobalt, lead, molybdenum, tungsten, tantalum, niobium, or an alloy of these metals may be used. The thickness of the first electrode and the second electrode is maintained in the range of 10 to 500nm, respectively.

A material capable of low temperature deposition is used on the first and second electrodes for electrode connection. Specifically, transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO) are used. At this time, the thickness of the metal for electrode connection to be deposited is maintained in the range of 10 to 500nm.

6 is a schematic cross-sectional view of one side of a reflective organic molecular solar cell according to the present invention. The leaky backlight light source incident through the transparent first electrode 9 is passed through the organic molecular solar cell layer 10 and recycled through the reflective second electrode 12, or the organic molecular solar cell layer 10 It is used as a light source. The first electrode 9 and the reflective second electrode 12 are the same as those of FIG. 5.

In order to describe the organic molecular solar cell layer 10 in detail, one side cross section of the organic molecular solar cell is schematically illustrated in FIGS. 7 and 8.

FIG. 7 is a schematic diagram of an organic molecular solar cell in which a donor 13 is formed on a first electrode 9, an acceptor 14 is stacked, and second electrodes 10 and 12 are formed. 8 illustrates an organic molecular solar cell in which a donor 13 and a receptor 14 are simultaneously mixed and formed on a first electrode 9, and then second electrodes 10 and 12 are formed.

7 and 8, a hole transport material and a hole injection material (hole transport layer) are interposed between the first electrode 9 and the organic molecular solar cell layer 10 as necessary, and the organic molecular solar cell layer 10 is provided. ) And an electron transfer material and an electron injection material (electron transport layer) may be further formed between the second electrode and the second electrodes 10 and 12.

The donor may be a polymer or a small molecule donor generally used in the art. The polymer donor may be poly (3-hexylthiophene-2,5-diyl) (compound 1), poly [3- (potassium-6-hexanoate) thiophene-2,5-diyl] (compound 2) , Poly (thiophen-2-5-diyl) (compound 3), poly (3-octylthiophene-2,5-diyl) (compound 4), poly [1-methoxy-4- (2- Ethylhexyloxy-2,5-phenylenevinylene)] (compound 5), poly [2-methoxy-5- (3,7-dimethyloctyloxy) -1,4-phenylenevinylene] ( Compound 6), poly (9,9-dioctylfluorenyl-2,7-diyl) (compound 7) and poly (9,9-dioctylfluorenyl-2,7-diyl) (compound 8) and the like can be used. Small molecule donors include pentacene (compound 9), zinc phthalocyanine (compound 10), kappa phthalocyanine (compound 11), titanium oxide phthalocyanine (compound 12) and 3- (2-benzothiazolyl) -7- (diethylamino) coumarin (Compound 13) and the like can be used.

The receptor may be a polymer or a small molecule receptor generally used in the art. As the polymer acceptor, poly [2,5-dihexyloxy-1,4- (1-cyanovinylene) phenylene] (compound 14) and the like can be used. The small molecule acceptors are fullerene-C60 (compound 15), (6,6) -phenyl-C61 butyric acid methyl ester (compound 16), [6,6] -phenyl-C71-butylic acid methyl ester (compound 17), N, N'-bis (2,5-di-tert-butylphenyl) -3,4,9,10-perylene-dicarboxyimide (Compound 18), N, N'-bis (phenyl) -3,4,9,10-perylene-dicarboxyimide (Compound 19), anthra [2 ", 1", 9 "; 4,5,6,6", 5 "10"; 4 ', 5' , 6 '] diisoquino [2,1-a; 2', 1'-a '] diperylimidine-12,25-dione (compound 20), perylene-3,4-9-, 10 Tetracarboxydione hydride (compound 21), perylene-3,4-9,10-tetracarboxydiimide (compound 22), 1,4,5,8-naphthalenetetracarboxylic dianhydride (compound 23) ), Perylene-3,4,9,10-tetracarboxylic acid N, N'-dimethylimide (compound 24) and perylene-3,4,9,10-tetracarboxylic acid N, N'-diheptylimide (Compound 25) and the like can be used.

It will be apparent to those skilled in the art that various donations and modifications can be made within the scope and spirit of the present invention, and the donors and receptors presented above are merely illustrative, and such variations and modifications are within the scope of the appended claims.

The invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection as defined by the appended claims.

Example 1 Fabrication of Organic Molecular Solar Cell Device by Wet Process

A glass substrate with an ITO (indium tin oxide) transparent electrode having a size of 25 mm x 25 mm x 1.1 mm was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, followed by ultraviolet ozone cleaning for 30 minutes. The glass substrate with a transparent electrode after cleaning is mounted on a holder of a spin coater, and the polyelectrode (3,4-ethylenediox), which is a hole injection material and a hole transfer material, is first covered by covering the transparent electrode on the surface of the side on which the transparent electrode is formed. Citiopen): Poly (styrenesulfonide) (PEDOT: PSS, Baytron P) was filtered with a 0.45 μm syringe filter and spin-coated at 1,000 rpm to form a 40 nm thick layer. The board | substrate with which PEDOT was formed was baked at 150 degreeC for 10 minutes. The P3HT (Compound 1) and the PCBM (Compound 16) dissolved in chlorobenzene in a ratio of 1: 0.8 on a PEDOT film-forming substrate were spin-coated at 1,000 rpm to form a film having a thickness of 100 nm. The substrate was then mounted in a holder of a vacuum deposition equipment and Al was deposited to a thickness of 100 nm. The substrate after Al deposition was annealed at 160 ° C. for 10 minutes to fabricate an organic molecular solar cell device. At this time, MIKASA spin coater (1H-DX2) was used for spin coating and VTSEL1000 deposition equipment was used for Al deposition. The efficiency of the organic molecular solar cell was used Newport's solar simulater (Class A ASTM E 927-05).

Example 2 Fabrication of Organic Molecular Solar Cell Device by Deposition Process

A glass substrate with an ITO transparent electrode having a size of 25 mm x 5 mm x 1.1 mm was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, followed by UV ozone cleaning for 30 minutes. The glass substrate with a transparent electrode after cleaning was mounted on the substrate holder of the vacuum deposition apparatus, and first, the transparent electrode was covered on the surface of the side on which the transparent electrode was formed so that CuPc (compound 11) as a hole transporting and injection material was 20 nm thick. Was deposited. CuPc (Compound 11) and C60 (Compound 15) were co-deposited at a weight ratio of 1: 1 to form a film with a thickness of 40 nm. Then, the following 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was deposited as an electron transporting material to a thickness of 10 nm. An Li film was formed thereon at a film formation rate of 0.1 kPa / sec and a film thickness of 1 nm, and Al was deposited on the Li film to form an electrode having a film thickness of 100 nm to fabricate an organic molecular solar cell. At the time of deposition, VTSEL1000's deposition equipment was used. The efficiency of the organic molecular solar cell was used Newport's solar simulater (Class A ASTM E 927-05).

Experimental Example

The liquid crystal panel 1, the optical sheet 2, the diffusion plate 3, the backlight light source 4, and the solar cell 5 are applied to the organic molecular solar cells manufactured in Examples 1 and 2 as shown in FIG. 1. And a display device laminated in the order of the reflector 6.

The display device employing the organic molecular solar cells of Examples 1 and 2 according to the present invention has a high productivity since the solar cell can be large-scaled by performing a solution process, and the thickness of the entire device is only a few hundred nm and is flexible. (flexible) it was possible to manufacture. That is, since the organic molecular solar cell has a small thickness constraint, the thinning effect is excellent as compared with a display device using a crystalline silicon solar cell, an amorphous silicon solar cell, a dye-sensitized solar cell, or the like.

In addition, it was confirmed that the conversion efficiency of the organic molecular solar cell of the present invention to the backlight electrical energy or the utilization efficiency of the light source due to reflection show an effect equal to or higher than the conventional one.

1 shows an example of a direct type liquid crystal display device incorporating a transmissive organic molecular solar cell.

2 shows an example of a direct type liquid crystal display device incorporating a reflective organic molecular solar cell.

3 shows an example of an edge type liquid crystal display device incorporating a transmissive organic molecular solar cell.

4 shows an example of an edge type liquid crystal display device incorporating a reflective organic molecular solar cell.

5 shows an example of a transmissive organic molecular solar cell,

6 shows an example of a reflective organic molecular solar cell,

Figure 7 shows an example of a donor, acceptor stacked organic molecular solar cell,

8 shows an example of a donor, an acceptor mixed organic molecular solar cell.

<Brief description of symbols for the main parts of the drawings>

1: liquid crystal panel 2: optical sheet 3: diffuser plate

4: backlight light source 5: solar cell 6: reflector

7: diffusion sheet 8: light guide plate 9: first electrode

10: organic molecular solar cell layer 11: transmissive second electrode 12: reflective second electrode

13: donor 14: receptor

Claims (13)

A display device comprising a backlight unit with an organic molecular solar cell. The display device of claim 1, wherein the organic molecular solar cell is built in the rear or side of the light source of the backlight unit. The display device of claim 1, wherein the organic molecular solar cell includes a reflective electrode to reflect the light source of the backlight unit. The display device of claim 1, wherein the organic molecular solar cell is formed by a wet or vacuum deposition process. The display device of claim 1, wherein the upper and lower electrodes of the organic molecular solar cell are transparent electrodes. The display device of claim 1, wherein the upper or lower electrode of the organic molecular solar cell is a reflective electrode. The display device of claim 1, wherein the organic molecular solar cell has a composite layer structure in which donors and acceptors are stacked, respectively. The display device of claim 1, wherein the organic molecular solar cell has a single layer structure in which a donor and a receptor are mixed. The display device of claim 1, wherein the organic molecular solar cell has a mixed structure in which a donor and a receptor are stacked, and a single layer in which a donor and a receptor are mixed. The display device of claim 1, further comprising a driving unit. The display device of claim 10, wherein the driving unit is configured to apply a power source obtained from the organic molecular solar cell to the display device. The display device of claim 10, wherein the driving unit stores a power source obtained from the organic molecular solar cell. The display device of claim 1, wherein the organic molecular solar cell is an auxiliary power supply device that covers a part of total power consumption of the display device.

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