JP2016174992A - Coating method and coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method which enables accurate coating with a coating liquid in response to a coating pattern.SOLUTION: In a coating method, a coating head 10 having an outer surface 11a as a coating area is prepared. The coating head 10 is arranged with a predetermined gap G on a coated surface 2a of a coated object 2. A coating liquid is supplied on the outer surface 11a of the coating head 10, and the coating liquid is made to flow along the outer surface 11a from a coating liquid supply position A to the gap G to form a coating liquid pool 4 between the coating head 10 and the coating surface 2a. At least one of the coating head 10 and the coated object 2 is moved, and the coated surface 2a is coated with the coating liquid from the coating liquid pool 4. A groove 14 for guiding the coating liquid in a width direction x of the outer surface 11a approximately orthogonal to a moving direction from the coating liquid supply position A is formed on the outer surface 11a of the coating head 10.SELECTED DRAWING: Figure 6

Description

  Embodiments described herein relate generally to a coating method and a coating apparatus.

  Organic thin-film solar cells and organic / inorganic hybrid solar cells using organic semiconductors are expected as low-cost solar cells because an inexpensive coating method can be applied to the formation of the active layer. A cell constituting the solar cell module has a structure in which an organic active layer is sandwiched between a transparent electrode and a counter electrode. Since the transparent electrode generally has low conductivity, the efficiency of extracting generated charges to the outside decreases as the cell area increases. Therefore, it is common to form a plurality of strip-shaped cells side by side and connect the plurality of cells in series.

  In order to realize the above-described organic thin-film solar cell and organic / inorganic hybrid solar cell at low cost, it is required to apply a coating solution for forming an organic active layer with high accuracy according to the cell pattern. Furthermore, since the film thickness of the organic active layer is about several tens nm to several hundreds nm, it is required to form such a very thin layer with high accuracy. However, the conventional coating method cannot accurately form the organic active layer pattern at a low cost. For example, a meniscus printing method is known as a coating method capable of printing an extremely thin layer on a relatively large area at a low cost. However, the conventional meniscus printing method has problems such as a shading pattern in the organic active layer pattern, and a variation in coating width and coating thickness between the coating start site and the coating end site. For these reasons, there is a demand for improvement in coating technology according to the cell pattern of the coating solution.

JP 2013-066683 A

  The problem to be solved by the present invention is to provide a coating method and a coating apparatus capable of accurately coating a coating solution according to a coating pattern.

  The coating method of the embodiment includes a step of preparing a coating head having an outer surface serving as a coating region, a step of arranging the coating head on the coating surface of the coating object with a predetermined gap, and a surface of the coating head. A step of forming a coating liquid reservoir between the coating head and the coating surface by supplying the coating solution and flowing the coating solution along the outer surface from the coating solution supply position toward the gap; and the coating head and coating And a step of moving at least one of the objects and applying the coating liquid from the coating liquid reservoir to the coating surface. On the outer surface of the coating head, there is provided a groove for guiding the coating liquid in the width direction of the outer surface substantially perpendicular to the moving direction from the position where the coating liquid is supplied.

It is a front view which shows schematic structure of the coating device of embodiment. It is a side view of the coating device shown in FIG. It is a figure which shows the coating process of the coating liquid using the coating device shown in FIG. It is a figure which shows the coating process of the coating liquid using the coating device shown in FIG. It is a figure which shows the coating process of the coating liquid using the coating device shown in FIG. It is a figure which shows the 1st structural example of the coating head in the coating device of embodiment. It is sectional drawing of the application | coating head shown in FIG. It is a figure which shows the 2nd structural example of the coating head in the coating device of embodiment. It is sectional drawing of the application | coating head shown in FIG. It is sectional drawing which shows the structural example of the organic thin-film solar cell produced using the coating device of embodiment. It is a top view of the organic thin film solar cell shown in FIG.

  Hereinafter, a coating method and a coating apparatus according to an embodiment will be described with reference to the drawings. In each embodiment, substantially the same constituent parts are denoted by the same reference numerals, and the description thereof may be partially omitted. The drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each part, and the like may differ from the actual ones. The term indicating the direction such as up and down in the description indicates the relative direction when the coating surface of the coating object to be described later is up unless otherwise specified, and the actual direction based on the gravitational acceleration direction May be different.

(First embodiment / application method and application apparatus)
FIG. 1 is a front view showing a schematic configuration of the coating apparatus of the embodiment, and FIG. 2 is a side view of the coating apparatus shown in FIG. The coating apparatus 1 shown in FIG. 1 and FIG. 2 is for applying a coating liquid 3 to a coating surface (surface) 2a of a substrate 2 that is a coating target, thereby forming a coating film having a desired shape on the substrate 2. Device. The coating apparatus 1 includes a coating head 10, a supply mechanism 20 that supplies the coating liquid 3 between the substrate 2 and the coating head 10, and a moving mechanism that moves at least one of the coating head 10 and the substrate 2. 30.

  The coating head 10 includes a head body 11 having a substantially cylindrical shape that is long in the x direction in the drawing. The head body 11 has an outer peripheral surface 11 a that serves as a coating area for the coating liquid 3. On the outer peripheral surface 11a of the head main body 11, the outer peripheral surface 11a of the head main body 11 is divided into a plurality of parts in the longitudinal direction so that the coating liquid 3 is applied in a multiple strip pattern to form a coating film. A groove 12 is provided. By providing the dividing groove 12 on the outer peripheral surface 11 a of the head body 11, the outer peripheral surface 11 a is divided into a plurality of application regions 13. The plurality of application regions 13 respectively correspond to the patterns of the multiple strip-shaped coating film. The dividing groove 12 only needs to be provided along at least a portion of the outer peripheral surface 11a of the head body 11 in the circumferential direction.

  1 and 2 show the head main body 11 having a substantially cylindrical shape, the shape of the head main body 11 is not limited to this. The head body 11 may have a polygonal columnar shape such as a hexagonal columnar shape. In such a case, the dividing groove 12 is provided along at least a part of the outer surface in a direction substantially orthogonal to the longitudinal direction of the head body 11. The plurality of application regions 13 are provided so as to divide the outer surface of the head main body 11 into a plurality in the longitudinal direction. The head body 11 is not limited to applying the coating liquid 3 in a multiple strip pattern, but may be a coating of the coating liquid 3 in a solid film pattern. In this case, the head main body 11 that does not have the dividing grooves 12 is used, and the outer peripheral surface 11a of the head main body 11 functions as one application region.

  The supply mechanism 20 includes a syringe pump 21 that supplies the coating liquid 3 between the head main body 11 of the coating head 10 and the coating surface 2 a of the substrate 2. The syringe pump 21 is installed in each of the plurality of application regions 13. The supply mechanism 20 is not limited to the syringe pump 21, and various discharge devices that can accurately discharge a small amount of material can be used. The moving mechanism 30 includes, for example, a stage 31 on which the substrate 2 that is an application target is placed, and a drive mechanism 32 for the stage 31. The drive mechanism 32 moves the stage 31 in the y direction in the figure. The drive mechanism 32 may have a mechanism for moving the stage 31 in the z direction in the figure. The moving mechanism 30 may be configured to move the coating head 10.

  Next, the process of apply | coating the coating liquid 3 to the board | substrate 2 using the coating device 1 of embodiment is demonstrated with reference to FIG. 3 thru | or FIG. 3 and 4 show only one application region 13 of the head body 11 for convenience. First, the coating head 10 is disposed on the coating surface 2a of the substrate 2 with a predetermined gap. The coating head 10 is disposed so that the separation groove 12 faces the coating surface 2a. In the case where the separation groove 12 is provided over the entire circumference of the outer peripheral surface, the coating head 10 may simply be disposed on the coating surface 2a with a predetermined gap. When the separation groove 12 is provided along a part of the outer peripheral surface, the region having the separation groove 12 is disposed so as to face the application surface 2a. In this state, the coating liquid 3 is supplied from the supply mechanism 20 between the outer peripheral surface of the coating head 10 (the outer peripheral surface 11 a of the head main body 11) and the coating surface 2 a of the substrate 2.

  The supply process of the coating liquid 3 is implemented as follows. First, as shown in FIGS. 3 and 4, the coating liquid 3 is supplied from the syringe pump 21 onto the outer peripheral surface 11 a of the head body 11. The coating liquid 3 supplied onto the outer peripheral surface 11a is directed from the supply position of the coating liquid 3 on the outer peripheral surface 11a (position where the coating liquid 3 first contacts) to the gap between the outer peripheral surface 11a and the coating surface 2a. And flows along the outer peripheral surface 11a. The coating liquid 3 that has flowed along the outer peripheral surface 11a reaches the gap between the outer peripheral surface 11a and the coating surface 2a, and then toward the width direction (the x direction in the figure) of the head body 11 (application region 13). Spread wet. Here, the width direction (x) of the head main body 11 is a direction substantially orthogonal to a moving direction (y direction in the drawing) of the substrate 2 described later.

  In this way, a coating liquid reservoir like the meniscus column 4 is formed in the gap between the outer peripheral surface 11a and the coating surface 2a. The meniscus column 4 is a columnar body having an arcuate curved surface, the gap distance between the head body 11 and the coating surface 2 a of the substrate 2, the properties of the coating solution 3 (viscosity, surface tension, etc.), and the coating solution 3. It has a desired shape according to the supply amount and the like. A coating film having a desired film thickness is formed according to the shape of the meniscus column 4, the properties such as the viscosity and surface tension of the coating liquid 3, the moving speed of the substrate 2, and the like. The meniscus column 4 is desirably formed in a gap between the outer peripheral surface 11a and the coating surface 2a in a uniform shape with respect to the x direction and the y direction.

  Next, as shown in FIG. 5, the stage 31 is driven to move the substrate 2 in the y direction, so that the coating liquid 3 is applied from the meniscus column 4 to the coating surface 2 a to form the coating film 5. Since the meniscus column 4 is formed for each application region 13 divided by the division grooves 12, the coating film 5 having the patterns 5 </ b> A divided corresponding to the shapes of the plurality of application regions 13 is formed. Each pattern 5A of the coating film 5 divided into a plurality of parts should have a shape that is ideally uniform in width and thickness in the lateral direction (x) and uniform in the longitudinal direction (y). Is required.

  However, the tip of the syringe pump 21 (the discharge portion / needle for the coating liquid 3) is considerably smaller than the width (x) of the coating region 13 so that a small amount of coating liquid can be accurately supplied. It has a size. For this reason, simply supplying the coating liquid 3 from the distal end portion of the syringe pump 21 onto the outer peripheral surface 11 a of the head main body 11 causes a gap between the outer peripheral surface 11 a of the head main body 11 and the application surface 2 a of the substrate 2. It is difficult to supply the coating liquid 3 uniformly. If the coating liquid 3 cannot be supplied uniformly, the shape of the meniscus column 4 may be poor, and further, the shape of the coating film pattern 5A may be poor or the density may be poor.

  For example, in the gap between the outer peripheral surface 11a and the coating surface 2a, if the coating liquid 3 cannot be sufficiently wetted and spread in the width direction (x) of the coating region 13, the width of the meniscus column 4 in the width direction (x) The shape becomes uneven. Further, if the coating liquid 3 is left so as to be sufficiently wet and spread in the width direction (x) of the coating region 13, the amount of the coating liquid 3 at the end in the width direction (x) may increase. These cause the shape defect in the short direction (x) of the coating film pattern 5A. If the wetting and spreading of the coating liquid 3 is insufficient, the width in the short side direction (x) of the coating film pattern 5A tends to be non-uniform with respect to the long side direction (y). Further, when the liquid amount at the end portion of the meniscus column 4 increases, only the end portion in the short direction (x) of the coating film pattern 5A tends to be thick.

  Moreover, when it is going to lengthen the length of the longitudinal direction (y) of the coating film pattern 5A, the width | variety of the transversal direction (x) of the coating film pattern 5A will become narrow gradually, and the thickness of the coating film pattern 5A will gradually increase. It tends to be thin. That is, the coating width and coating thickness of the coating liquid 3 are likely to vary between the coating start site and the coating end site of the coating liquid 3. In the coating step of the coating liquid 3, after the coating liquid 3 is supplied to the gap, the supply of the coating liquid 3 is stopped and then the substrate 2 is moved for coating, and the substrate 2 while the coating liquid 3 is continuously supplied. In some cases, the coating is moved. When the substrate 2 is moved while supplying the coating liquid 3 in order to increase the length in the longitudinal direction (y) of the coating film pattern 5A, the short direction (x ) Increases in the vicinity of the center, and a streak pattern is likely to occur near the center of the coating film pattern 5A.

  In order to solve the problems described above, in the coating apparatus 1 of the embodiment, the coating liquid 3 is guided to the outer circumferential surface 11 of the head body 11 from the supply position of the coating liquid 3 in the width direction (x) of the outer circumferential surface 11. A groove is provided. By using the head body 11 having such a guide groove for the coating liquid 3, the coating liquid 3 can be uniformly supplied to the gap between the outer peripheral surface 11 a of the head body 11 and the coating surface 2 a of the substrate 2. As a result, the shape with respect to the width direction (x) of the meniscus column 4 and the movement direction (y) of the substrate 2 can be made uniform. Therefore, since the occurrence of a defective shape or a shading defect of the coating film pattern 5A is suppressed, it is possible to form the coating film 5 having the coating film pattern 5A having excellent shape accuracy and density accuracy with high reproducibility. Below, the coating apparatus 1 using the head main body 11 which has the induction groove | channel of the coating liquid 3 is explained in full detail.

  A first configuration example of the coating head 10 having the guide groove for the coating liquid 3 will be described with reference to FIGS. 6 and 7. The coating head 10 shown in FIGS. 6 and 7 includes a head body 11 having an outer peripheral surface 11a provided with a groove 14 for guiding the coating liquid 3 in the width direction (x). The guide groove 14 applies the coating liquid 3 flowing from the supply point A of the coating liquid 3 on the outer peripheral surface 11a toward the gap G between the outer peripheral surface 11a and the coating surface 2a in the width direction (x) of the outer peripheral surface 11. It is provided to guide to. The guide groove 14 shown in FIGS. 6 and 7 is branched so that the guide path in the groove is separated from the supply point A in the width direction (x). Further, the guide groove 14 is branched a plurality of times so that the coating liquid 3 reaches the gap G from a plurality of locations. The number of branches of the guide groove 14 is appropriately set in consideration of the width (x) of the application region 13 and the fluidity of the application liquid 3.

  The coating liquid 3 supplied onto the outer peripheral surface 11a of the head body 11 having the guide groove 14 described above flows in the guide groove 14 from the supply point A, and further splits at the branch point of the guide groove 14, and this split flow is By repeating, the gap G is reached from a plurality of locations. By causing the coating liquid 3 to reach the gap G from a plurality of locations, the supply amount of the coating liquid 3 in the width direction (x) of the gap G is made uniform. Therefore, the meniscus column 4 having a uniform shape in the width direction (x) of the application region 13 can be obtained. Furthermore, by uniformizing the supply amount of the coating liquid 3 in the width direction (x) of the coating region 13, the shape of the meniscus column 4 in the movement direction (y) of the substrate 2 is also uniformed. By applying the coating liquid 3 to the coating surface 2a from the meniscus column 4 as described above, it is possible to suppress the occurrence of poor shape, shading, and the like of the coating film pattern 5A. Specifically, it is possible to suppress the occurrence of a defect in which the width in the short direction (x) of the coating film pattern 5A varies or only the end portion in the short direction (x) becomes thick. .

  Even in the case where the coating film 5 is formed by moving the substrate 2 while supplying the coating liquid 3, the coating liquid 3 is supplied to the meniscus column 4 from a plurality of locations. It is possible to suppress the increase in density and the generation of a streak pattern based thereon. Furthermore, since it becomes possible to form the favorable coating film 5 while supplying the coating liquid 3, the length of the coating film 5 in the longitudinal direction (y) can be further increased. In such a case, the fluctuation | variation of the width | variety and thickness of the transversal direction (x) of the coating film pattern 5A can be suppressed. Therefore, it is possible to form the coating film 5 having the pattern 5A having a longer length in the longitudinal direction (y) with good reproducibility while improving the shape accuracy of the width and thickness of the pattern 5A.

  Next, a second configuration example of the coating head 10 having the guide groove for the coating liquid 3 will be described with reference to FIGS. The coating head 10 shown in FIGS. 8 and 9 includes a head body 11 having an outer peripheral surface 11a provided with a groove 15 for guiding the coating liquid 3 in the width direction (x) of the outer peripheral surface 11a. The guide groove 15 is provided along the width direction (x) of the outer peripheral surface 11 a between the supply point A of the coating liquid 3 on the outer peripheral surface 11 a and the gap G, and functions as a buffer region for the coating liquid 3. To do. The guide groove 15 has a depth that functions as a buffer region for the coating liquid 3. In other words, the guide groove 15 has a depth enough to temporarily store the coating liquid 3.

  The coating liquid 3 supplied onto the outer peripheral surface 11 a of the head body 11 having the guide groove 15 flows from the supply point A along the outer peripheral surface 11 a and is temporarily stored in the guide groove 15. The coating liquid 3 accommodated in the guide groove 15 spreads in the width direction (x), and the inside of the guide groove 15 is filled with the coating liquid 3. The coating liquid 3 filling the inside of the guide groove 15 overflows from the entire region in the width direction (x) of the guide groove 15 and further flows toward the gap G along the outer peripheral surface 11a. Accordingly, since the supply amount of the coating liquid 3 in the width direction (x) of the gap G is made uniform, the meniscus column 4 having a uniform shape in the width direction (x) of the coating region 13 can be obtained. Furthermore, by uniformizing the supply amount of the coating liquid 3 in the width direction (x) of the coating region 13, the shape of the meniscus column 4 in the movement direction (y) of the substrate 2 is also uniformed.

  By applying the coating liquid 3 to the coating surface 2a from the meniscus column 4 as described above, it is possible to suppress the occurrence of poor shape, shading, and the like of the coating film pattern 5A. Furthermore, even when the substrate 2 is moved while supplying the coating liquid 3 to form the coating film 5, the coating liquid 3 is supplied from the entire region in the width direction (x) to the meniscus column 4, It is possible to suppress the local concentration of the coating liquid 3 and the generation of a streak pattern based thereon. Furthermore, since it becomes possible to form the favorable coating film 5 while supplying the coating liquid 3, the length of the coating film 5 in the longitudinal direction (y) can be further increased. In such a case, the fluctuation | variation of the width | variety and thickness of the transversal direction (x) of the coating film pattern 5A can be suppressed. Therefore, it is possible to form the coating film 5 having the pattern 5A having a longer length in the longitudinal direction (y) with good reproducibility while improving the shape accuracy of the width and thickness of the pattern 5A.

Second Embodiment / Organic Thin Film Solar Cell
The coating apparatus 1 and the coating method using the same according to the embodiment are suitably used for, for example, a process of forming an organic active layer in a method for manufacturing an organic thin film solar cell module. 10 and 11 show an example of the organic thin-film solar cell module 100 to which the coating method of the embodiment is applied to the organic active layer forming step. In FIG. 11, the counter electrode is not shown. The organic thin film solar cell module 100 shown in FIG. 10 and FIG. 11 has a plurality of cell portions 102A and 102B connected in series. A plurality of separated first electrode layers 103A and 103B are formed on the support substrate 101. Photoelectric conversion layers 104A and 104B are formed on the first electrode layers 103A and 103B, respectively. Second electrode layers 105A and 105B are formed on the photoelectric conversion layers 104A and 104B, respectively. The second electrode layer 105A of the cell portion 102A is electrically connected to the first electrode layer 103B of the cell portion 102B.

  In the organic thin film solar cell module 100 shown in FIG. 10, light such as sunlight or illumination light is irradiated from the support substrate 101 side to the photoelectric conversion layer 104 (104A, 104B). The photoelectric conversion layer 104 includes, for example, an organic active layer including a p-type semiconductor and an n-type semiconductor, and a first intermediate layer (not shown) (for example, disposed between the first electrode layer 103 and the organic active layer). An electron transport layer) and a second intermediate layer (for example, a hole transport layer) (not shown) disposed between the organic active layer and the second electrode layer 105. When the organic active layer absorbs the light applied to the photoelectric conversion layer 104, charge separation occurs at the phase interface between the p-type semiconductor and the n-type semiconductor, thereby generating electrons and holes that are paired therewith. Of the electrons and holes generated in the organic active layer, for example, electrons are collected by the first electrode layer 103, and holes are collected by the second electrode layer 105.

  The support substrate 101 is made of a light transmissive material. As a constituent material of the support substrate 101, inorganic materials such as alkali-free glass, quartz glass, and sapphire, organic materials such as polyethylene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polyamideimide, and liquid crystal polymer Is mentioned.

  The first electrode layer 103 is made of a material having optical transparency and conductivity. Constituent materials of the first electrode layer 103 include indium oxide, zinc oxide, tin oxide, indium tin oxide (ITO), tin oxide doped with fluorine (FTO), indium-zinc oxide (IZO), indium-gallium. -Conductive metal oxides such as zinc oxide (IGZO), metals such as gold, platinum, silver, copper, titanium, zirconium, cobalt, nickel, indium, aluminum, alloys containing these metals, or poly (3,4) -Conductive polymers such as ethylenedioxythiophene) / poly (4-styrenesulfonic acid) (PEDOT / PSS). The first electrode layer 103 is formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, a plating method, a coating method, or the like.

  The organic active layer has a function of performing charge separation by irradiated light and includes a p-type semiconductor and an n-type semiconductor. For the p-type semiconductor, a material having an electron donating property is used. For the n-type semiconductor, an electron-accepting material is used. Both the p-type semiconductor and the n-type semiconductor constituting the organic active layer may be an organic material, or one of them may be an organic material.

  Examples of the p-type semiconductor contained in the organic active layer include polythiophene and derivatives thereof, polypyrrole and derivatives thereof, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, and polyvinylcarbazole and derivatives thereof. , Polysilane and derivatives thereof, polysiloxane derivatives having aromatic amines in the side chain or main chain, polyaniline and derivatives thereof, phthalocyanine derivatives, porphyrin and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene and derivatives thereof, etc. These may be used in combination. These copolymers may be used, and examples thereof include a thiophene-fluorene copolymer and a phenylene ethynylene-phenylene vinylene copolymer.

  As the p-type organic semiconductor, it is preferable to use polythiophene which is a conductive polymer having π conjugation and a derivative thereof. Polythiophene and its derivatives can ensure excellent stereoregularity and have relatively high solubility in a solvent. Polythiophene and derivatives thereof are not particularly limited as long as they are compounds having a thiophene skeleton. Specific examples of polythiophene and derivatives thereof include poly (3-methylthiophene), poly (3-butylthiophene), poly (3-hexylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), Polyalkylthiophene such as poly (3-dodecylthiophene), polyarylthiophene such as poly (3-phenylthiophene), poly (3- (p-alkylphenylthiophene)), poly (3-butylisothionaphthene), poly Polyalkylisothionaphthenes such as (3-hexylisothionaphthene), poly (3-octylisothionaphthene), poly (3-decylisothionaphthene), and polyethylenedioxythiophene. In addition, a copolymer of carbazole, benzothiadiazole, and thiophene (for example, poly [N-9′-heptadecanyl-2,7-carbazole-alt-5,5- (4,7-di-2-thienyl-2) ', 1', 3'-benzothiadiazole)] / PCDTBT) is known as a compound having excellent photoelectric conversion efficiency.

For the n-type semiconductor contained in the organic active layer, fullerene, fullerene derivatives and the like are used. The fullerene derivative should just have a fullerene skeleton. Fullerenes and fullerene derivatives include fullerenes such as C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₄ , fullerene oxides in which at least some of the carbon atoms of these fullerenes are oxidized, and some carbon atoms of the fullerene skeleton. Examples thereof include a compound modified with an arbitrary functional group, a compound in which these functional groups are bonded to each other to form a ring, and the like.

Functional groups used in fullerene derivatives include hydrogen atoms, hydroxyl groups, halogen atoms such as fluorine atoms and chlorine atoms, alkyl groups such as methyl groups and ethyl groups, alkenyl groups such as vinyl groups, cyano groups, and methoxy groups. And an alkoxy group such as ethoxy group, an aromatic hydrocarbon group such as phenyl group and naphthyl group, and an aromatic heterocyclic group such as thienyl group and pyridyl group. Specific examples of fullerene derivatives include hydrogenated fullerenes such as C ₆₀ H ₃₆ and C ₇₀ H ₃₆ , fullerene oxides obtained by oxidizing C ₆₀ and C ₇₀ , fullerene metal complexes, and the like. As the fullerene derivative, it is preferable to use [6,6] phenyl C ₆₁ butyric acid methyl ester (60PCBM), [6,6] phenyl C ₇₁ butyric acid methyl ester (70PCBM), bisindene C ₆₀ (60ICBA) or the like.

  The organic active layer has a bulk heterojunction structure including, for example, a mixture of a p-type semiconductor material and an n-type semiconductor material. The bulk heterojunction organic active layer has a microphase separation structure of a p-type semiconductor material and an n-type semiconductor material. In the organic active layer, the p-type semiconductor phase and the n-type semiconductor phase are phase-separated from each other to form a nano-order pn junction. When the organic active layer absorbs light, negative charges (electrons) and positive charges (holes) are separated at these phase interfaces, and are transported to the electrodes 103 and 105 through each semiconductor.

  For the bulk heterojunction type organic active layer, a solution obtained by dissolving a p-type semiconductor and an n-type semiconductor in a solvent is used as a coating solution, and this coating solution is used as a support substrate (transparent electrode) having a first electrode layer (transparent electrode) 103 and the like. Substrate) 101 is applied by coating. The coating liquid constituting the organic active layer is applied onto the support substrate (transparent substrate) 101 by applying the coating apparatus 1 of the embodiment and a coating method using the same. As a result, the photoelectric conversion layers 103A and 103B having a multiple strip-like pattern as shown in FIG. 11 can be formed with high accuracy and at low cost. Although the thickness of an organic active layer is not specifically limited, 10 nm-1000 nm are preferable.

  The electron transport layer has a function of blocking holes generated in the organic active layer and selectively and efficiently transporting electrons to the first electrode layer 103. Examples of the constituent material of the electron transport layer include metal oxides such as zinc oxide, titanium oxide, and gallium oxide, and organic materials such as polyethyleneimine. The hole transport layer has a function of blocking electrons generated in the organic active layer and transporting holes to the second electrode layer 105 selectively and efficiently. Examples of the constituent material of the hole transport layer include organic conductive polymers such as PEDOT / PSS, polythiophene, polypyrrole, polyacetylene, triphenylenediamine polypyrrole, and polyaniline, and metal oxides such as molybdenum oxide and vanadium oxide. The electron transport layer and the hole transport layer are formed by, for example, a vacuum film formation method such as a vacuum deposition method or a sputtering method, a sol-gel method, a coating method, or the like.

  The second electrode layer 105 is made of a material having conductivity and, in some cases, light transmission. As the constituent material of the second electrode layer 105, for example, platinum, gold, silver, copper, nickel, cobalt, iron, manganese, tungsten, titanium, zirconium, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, Metals such as rubidium, cesium, calcium, magnesium, barium, samarium and terbium, alloys containing them, conductive metal oxides such as indium-zinc oxide (IZO), conductive polymers such as PEDOT / PSS Or carbon materials such as graphene and carbon nanotubes. The second electrode layer 105 is formed by, for example, a vacuum film formation method such as a vacuum deposition method or a sputtering method, a sol-gel method, a coating method, or the like.

By applying the coating apparatus 1 of the embodiment and the coating method using the same, it is possible to manufacture the organic thin-film solar cell 100 including the multiple strip-like photoelectric conversion layers 103A and 103B with high accuracy and at low cost. become. The coating apparatus 1 of the embodiment and the coating method using the same are not limited to the organic active layer forming process of the organic thin-film solar cell, but the forming process of applying the coating method such as the electron transporting layer and hole transporting layer forming process It is applicable to. Furthermore, the present invention can be applied to a manufacturing process of an organic / inorganic hybrid solar cell using an organic / inorganic hybrid perovskite compound in an active layer, not limited to the manufacturing process of an organic thin film solar cell. For example, as a perovskite semiconductor used in the active layer, (CH ₃ NH ₃ ) BX ₃ (B is a metal atom such as Pb or Sn, and X is a halogen element such as I, Br, or Cl) is known. . The coating apparatus 1 of the embodiment can be applied to a manufacturing process of a solar cell including a constituent layer containing an organic substance as at least a part of such a forming material, and further to a manufacturing process of a light emitting element or an optical sensor.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Coating apparatus, 2 ... Substrate, 3 ... Coating liquid, 4 ... Coating liquid reservoir (meniscus column), 5 ... Coating film, 10 ... Coating head, 11 ... Head body, 12 ... Separation groove, 13 ... Coating area, 14 , 15 ... guide groove, 20 ... supply mechanism, 21 ... syringe pump, 30 ... movement mechanism, 31 ... stage, 32 ... stage drive mechanism.

Claims (8)

Preparing a coating head having an outer surface to be a coating region;
Arranging the coating head on the coating surface of the coating object with a predetermined gap;
By supplying a coating liquid onto the outer surface of the coating head and causing the coating liquid to flow along the outer surface from the supply position of the coating liquid toward the gap, a gap between the coating head and the coating surface is obtained. Forming a coating liquid reservoir in
Moving at least one of the application head and the object to be applied, and applying the application liquid from the application liquid reservoir to the application surface;
A coating method, wherein a groove for guiding the coating liquid is provided on the outer surface of the coating head from a supply position of the coating liquid in a width direction of the outer surface substantially orthogonal to the moving direction.   The coating method according to claim 1, wherein the groove has a shape that reaches the gap while branching from a supply position of the coating solution.   The coating method according to claim 2, wherein the groove has a plurality of branch portions.   The coating method according to claim 1, wherein the groove is provided along a width direction of the outer surface between a supply position of the coating liquid and the gap. A coating head having an outer surface to be a coating region and disposed with a predetermined gap on a coating surface of a coating target;
A supply mechanism for supplying a coating liquid onto the outer surface of the coating head so as to form a coating liquid pool between the coating head and the coating surface;
A moving mechanism for moving at least one of the application head and the application object so as to apply the application liquid from the application liquid reservoir to the application surface;
The coating head is arranged on the outer surface so as to guide the coating liquid flowing along the outer surface from the supply position of the coating solution toward the gap in the width direction of the outer surface substantially perpendicular to the moving direction. A coating device having a groove provided.   The coating apparatus according to claim 5, wherein the groove has a shape that reaches the gap while branching from a supply position of the coating liquid.   The coating apparatus according to claim 6, wherein the groove has a plurality of branch portions.   The coating apparatus according to claim 5, wherein the groove is provided along a width direction of the outer surface between a supply position of the coating liquid and the gap.

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