JP6729602B2 - Method for manufacturing photoelectric conversion element - Google Patents

Description

The present invention relates to a method for manufacturing a photoelectric conversion element, and particularly to a method for manufacturing a photoelectric conversion element such as an electroluminescence element and a solar cell.

Photoelectric conversion elements are widely used in various fields such as electroluminescence elements that emit light when a voltage is applied and solar cells that generate electromotive force when light is incident.

For example, a light emitting diode (LED), which is a type of electroluminescence element, includes a pair of electrodes (anode and cathode) and a light emitting layer arranged between these electrodes. When a voltage is applied between both electrodes, holes and electrons are injected into the light emitting layer from each electrode. When the holes and electrons are recombined in the light emitting layer, binding energy is generated, and the light emitting material in the light emitting layer is excited by this binding energy. Light emission occurs when the excited light emitting material returns to the ground state. Therefore, the LED can be used as a light emitting element or lighting.

On the other hand, the solar cell has a pair of electrodes and a photoelectric conversion layer arranged between them. When light is incident on the photoelectric conversion layer, holes and electrons are generated in the photoelectric conversion layer to generate electromotive force. Electric power can be taken out of the system by taking out holes and electrons from separate electrodes.

In the field of photoelectric conversion elements such as LEDs and solar cells, various configurations have been proposed in order to further improve the characteristics of the elements (for example, Patent Document 1).

International Publication No. 2015/098458

As described above, regarding the photoelectric conversion element, various measures have been proposed in order to improve the characteristics of the element. For example, Patent Document 1 described above describes that an amorphous thin film of an oxide containing zinc (Zn) and silicon (Si) is used for an electron transport layer in a photoelectric conversion element.

However, the photoelectric conversion element is still required to have improved characteristics such as the luminous efficiency of the electroluminescent element and the power generation efficiency of the solar cell.

The present invention has been made in view of such a background, and an object of the present invention is to provide a method for manufacturing a photoelectric conversion element in which the characteristics are significantly improved as compared with the prior art.

In the present invention, a method for manufacturing a photoelectric conversion element,
(1) disposing a first electrode on the substrate,
(2) A metal oxide containing zinc (Zn) and oxygen (O) and further containing at least one of silicon (Si) and tin (Sn) on the first electrode. Disposing a first thin film,
(3) applying a pressure to the substrate having the first electrode and the first thin film with a gas,
(4) disposing a photoelectric conversion layer that is a layer that converts an applied voltage into light or a layer that converts incident light into electric power, above the first thin film;
(5) disposing a second electrode on the photoelectric conversion layer,
Is provided.

According to the present invention, it is possible to provide a method for manufacturing a photoelectric conversion element, the characteristics of which are significantly improved as compared with the conventional method.

FIG. 3 is a diagram schematically showing an example of a flow of a method for manufacturing an organic electroluminescent element according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the structure of an organic electroluminescence device manufactured by the method according to the embodiment of the present invention. FIG. 3 is a diagram schematically showing an example of a flow of a method for manufacturing an organic solar cell according to an embodiment of the present invention. 1 is a cross-sectional view schematically showing a structure of an organic solar cell manufactured by a method according to an exemplary embodiment of the present invention. 6 is a graph showing the relationship between the applied voltage and the emission luminance obtained in each organic electroluminescence element sample.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings.

In one embodiment of the present invention, a method of manufacturing a photoelectric conversion element,
(1) disposing a first electrode on the substrate,
(2) A metal oxide containing zinc (Zn) and oxygen (O) and further containing at least one of silicon (Si) and tin (Sn) on the first electrode. Disposing a first thin film,
(3) applying a pressure to the substrate having the first electrode and the first thin film with a gas,
(4) disposing a photoelectric conversion layer that is a layer that converts an applied voltage into light or a layer that converts incident light into electric power, above the first thin film;
(5) disposing a second electrode on the photoelectric conversion layer,
Is provided.

Here, in the present application, the “photoelectric conversion element” means a general term for elements having a “photoelectric conversion layer”. Further, the “photoelectric conversion layer” is a layer in which electric energy is generated when light energy is introduced (irradiated) (photo-electric conversion layer), and a layer in which light emission is generated when electric energy is introduced (applied). It also includes (electro-optical conversion layer).

For example, when the “photoelectric conversion layer” is composed of a light emitting layer that emits light when a voltage is applied, the “photoelectric conversion element” including such a “photoelectric conversion layer” is an electroluminescence element (EL element). Such an EL element may be an organic EL element in which the "photoelectric conversion layer" is composed of an organic light emitting layer or an inorganic EL element in which the "photoelectric conversion layer" is composed of an inorganic light emitting layer. Good.

On the other hand, when the “photoelectric conversion layer” is composed of a layer in which electromotive force is generated by light irradiation, the “photoelectric conversion element” including such a “photoelectric conversion layer” is a solar cell. In addition, such a solar cell may be an organic solar cell in which the “photoelectric conversion layer” is an organic layer or an inorganic solar cell in which the “photoelectric conversion layer” is an inorganic layer.

In the method for manufacturing a photoelectric conversion element according to the present invention, the characteristics of the element can be significantly improved as compared with the conventional one, as described in detail below.

Hereinafter, the manufacturing method according to one embodiment of the present invention will be described in detail by taking the case where the photoelectric conversion element is an electroluminescence element and a solar cell as an example.

(Method of Manufacturing EL Element According to One Embodiment of the Present Invention)
A method of manufacturing an EL element according to an embodiment of the present invention (hereinafter, referred to as “first manufacturing method”) will be described with reference to FIGS. 1 and 2. In addition, here, the case where an organic electroluminescence element (organic EL element) is manufactured as an EL element will be described as an example.

FIG. 1 schematically shows an example of the flow of the first manufacturing method. Further, FIG. 2 schematically shows a cross section of an EL element manufactured by the first manufacturing method.

As shown in FIG. 1, the first manufacturing method is
(A) disposing the first electrode on the substrate (step S110),
(B) A metal oxide containing zinc (Zn) and oxygen (O) on the first electrode and further containing at least one of silicon (Si) and tin (Sn). Disposing the thin film of No. 1 (step S120),
(C) applying a pressure to the substrate having the first electrode and the first thin film with a gas (step S130),
(D) placing a first additional layer on top of the first thin film (step S140),
(E) disposing an organic light emitting layer on top of the first additional layer (step S150),
(F) disposing a second additional layer on the organic light emitting layer (step S160),
(G) disposing a second electrode on the second additional layer (step S170),
In this order.

As shown in FIG. 2, in the first manufacturing method, for example, on the substrate 110, the first electrode (cathode) 120, the first thin film 130, the first additional layer 140, the organic light emitting layer 150, the first The organic EL device 100 including the two additional layers 160 and the second electrode (anode) 170 in this order is manufactured.

Hereinafter, each step shown in FIG. 1 will be described. In the following description, the reference numerals shown in FIG. 2 are used to represent each member for clarity.

(Step S110)
First, the substrate 110 is prepared.

The substrate 110 has a role of supporting each layer constituting the organic EL element 100 on the upper portion. The material of the substrate 110 is not particularly limited. In FIG. 2, when the light extraction surface of the organic EL element 100 is on the lower side (that is, the substrate 110 side), the substrate 110 is made of a transparent material. For example, a glass substrate, a plastic substrate, or the like is used as the substrate 110.

Next, the first electrode 120 is disposed on the substrate 110.

The first electrode 120 is usually made of metal. When the light extraction surface of the organic EL element 100 is the lower side (that is, the substrate 110 side), the first electrode 120 is made of a transparent material. As the first electrode 120, a transparent metal oxide thin film such as ITO (indium tin oxide) is used.

The first electrode 120 may be, for example, aluminum, silver, gold, magnesium, calcium, titanium, yttrium, lithium, gadolinium, ytterbium, ruthenium, manganese, molybdenum, vanadium, chromium, tantalum, or an alloy of the aforementioned metals. Any metal material may be used. Alternatively, the first electrode 120 includes, for example, ITO, antimony oxide (Sb ₂ O ₃ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), IZO (Indium Zinc). _{oxide), AZO (ZnO-Al} 2 O 3: aluminum zinc oxide _{doped), GZO (ZnO-Ga 2} O 3: gallium zinc oxide doped), Nb-doped _TiO 2, Ta-doped TiO ₂ , And IWZO (In ₂ O ₃ —WO ₃ —ZnO: indium oxide doped with tungsten trioxide and zinc oxide).

The method for installing the first electrode 120 is not particularly limited.

The first electrode 120 may be formed by a vapor deposition method (vacuum vapor deposition method and electron beam vapor deposition method), an ion plating method, a laser ablation method, a sputtering method, or the like.

Typically, the thickness of the first electrode 120 is in the range of 50 nm to 150 nm. When the thickness is 50 nm or more, a low resistance electrode is formed, which is preferable. When the thickness is 150 nm or less, the step difference at the edge of the electrode is small, the coverage of the film formed later is good, and the light emitting area or light receiving area can be widened, which is preferable. When a transparent metal material is used as the first electrode 120, the thickness of the first electrode 120 is preferably in the range of 2 nm to 50 nm. The thickness of 2 nm or more is preferable because the conductivity applicable to the photoelectric conversion element can be obtained. When it is 50 nm or less, transparency can be secured, which is preferable.

(Step S120)
Next, the first thin film 130 is disposed on the first electrode 120.

The first thin film 130 is made of a metal oxide containing zinc (Zn) and oxygen (O), and further containing at least one of silicon (Si) and tin (Sn).

When the first thin film 130 is made of a metal oxide containing zinc (Zn), silicon (Si), and oxygen (O) (hereinafter, referred to as ZSO), it is a commonly used oxide semiconductor such as ZnO. The work function is as low as 3.5 eV, for example, and the electron injection characteristics to the organic material are particularly excellent. In this case, the value of Zn/(Zn+Si) is, for example, in the range of 0.30 to 0.95 in terms of molar ratio. When it is 0.30 or more, a sufficiently large electron mobility can be obtained, and an increase in drive voltage of the photoelectric conversion element can be suppressed. When it is 0.95 or less, a smooth surface can be obtained, so that short circuit can be suppressed. The molar ratio of Zn/(Zn+Si) may be 0.70 to 0.94, 0.80 to 0.92, or 0.85 to 0.90. ..

The first thin film 130 preferably has a chemical composition represented by xZnO-(1-x)SiO ₂ (x=0.30 to 0.95). When x is 0.30 or more, a sufficiently large electron mobility can be obtained, and an increase in drive voltage of the photoelectric conversion element can be suppressed. When x is 0.95 or less, a particularly smooth surface can be obtained, so that a short circuit can be suppressed. x may be 0.70 to 0.94, may be 0.80 to 0.92, or may be 0.85 to 0.90.

The first thin film 130 is preferably in the form of a complex oxide.

When the first thin film 130 is composed of a metal oxide containing zinc (Zn), tin (Sn) and oxygen (O) (hereinafter referred to as ZTO), the etching rate is appropriate, and the first thin film 130 does not overetch. Since the desired shape can be formed, the organic EL element or the solar cell can be stably manufactured. In this case, the first thin film 130 preferably contains SnO ₂ in an amount of 15 mol% or more and 95 mol% or less in terms of oxide, with respect to a total of 100 mol% of ZnO and SnO ₂ . When SnO ₂ is 15 mol% or more, the crystallization temperature is high, and it is difficult to crystallize in the heat treatment steps performed in various processes. When SnO ₂ is 95 mol% or less, it is easy to sinter, a good oxide target is obtained, and a thin film is easily formed. SnO ₂ may be 30 mol% or more and 70 mol% or less, 35 mol% or more and 60 mol% or less, and 40 mol% or more and 50 mol% or less.

When the first thin film 130 is composed of a metal oxide containing zinc (Zn), tin (Sn), silicon (Si) and oxygen (O) (hereinafter referred to as ZTSO), it has a low work function and Since the etching rate is appropriate and high transparency is obtained, the device characteristics of the organic EL device or the solar cell are improved. In this case, the first thin film 130, in terms of oxide, ZnO, relative to SnO _2, and the total 100 mol% of SiO _2, SnO ₂ is 12 mol% or more, and preferably not more than 97 mol%. When SnO ₂ is 15 mol% or more, the crystallization temperature is high, and it is difficult to crystallize in the heat treatment steps performed in various processes. When SnO ₂ is 95 mol% or less, it is easy to sinter, a good oxide target is obtained, and a thin film is easily formed. SnO ₂ may be 30 mol% or more and 70 mol% or less, 35 mol% or more and 60 mol% or less, and 40 mol% or more and 50 mol% or less.

When the first thin film 130 is made of ZTSO, it is preferable that SiO ₂ is 5 mol% or more and 30 mol% or less with respect to a total of 100 mol% of ZnO, SnO ₂ , and SiO _{2 in} terms of oxide. .. If SiO ₂ is 5 mol% or more and 30 mol% or less, the electron affinity is not too large and the volume resistivity is not too high. SiO ₂ may be 7 mol% or more and 20 mol% or less, or 10 mol% or more and 15 mol% or less.

The first thin film 130 may further include one or more metal components selected from the group consisting of titanium (Ti), indium (In), gallium (Ga), niobium (Nb), and aluminum (Al). .. The content of these metal components is, in terms of oxide, preferably 15 mol% or less, and more preferably 10 mol, based on 100 mol% of the total of oxides of ZnO, SiO ₂ , SnO ₂ , and other metal components. % Or less, and more preferably 5 mol% or less. In terms of oxide, these metals are calculated in the form of TiO ₂ , In ₂ O ₃ , Ga ₂ O ₃ , Nb ₂ O ₅ , or Al ₂ O ₃ .

When the film thickness is 200 nm or more, the composition of the thin film of the first thin film 130 can be analyzed by performing substrate correction using EPMA. When the film thickness is 700 nm or more, the composition of the first thin film 130 can be analyzed by using SEM-EDX at an acceleration voltage of 10 kV. The analysis can also be performed by performing substrate correction using XRF. When using ICP, the first thin film 130 can be analyzed by using a volume of 1 mm ³ or more.

The first thin film 130 is preferably amorphous or in an amorphous state. Here, the amorphous means a substance that does not give a sharp peak in X-ray diffraction measurement. Specifically, when the X-ray wavelength λ is 0.154 nm and the Scherrer constant K is 0.9, the crystallite diameter (Scherrer diameter) obtained by the Scherrer equation represented by the following equation (1) is 5. It is 2 nm or less. When the Scherrer constant L is K, the X-ray wavelength is λ, the half width is β, and the peak position is θ, the Scherrer diameter L is

L=Kλ/(β cos θ) Equation (1)

It is represented by. In addition, that the amorphous state is dominant means that the amorphous state is present in a volume ratio of more than 50%. It is preferable that the first thin film 130 is amorphous or is in an amorphous state because the film surface has high smoothness and short-circuiting of the element can be prevented. The first thin film 130 may be fine crystals or may be a mixture of amorphous and fine crystals. Here, the microcrystal is a crystal having a Scherrer diameter larger than 5.2 nm and smaller than 100 nm. It is preferable that the first thin film 130 be microcrystalline because the conductivity is improved. It is preferable that the first thin film 130 has a form in which amorphous and microcrystalline are mixed, because both smoothness and conductivity are improved.

The electron mobility of the first thin film 130 may be 10 ⁻⁴ cm ² ·V ⁻¹ s ⁻¹ to 10 ² cm ² ·V ⁻¹ s ⁻¹ , and 10 ⁻³ cm ² ·V ^−1. s ^-1 to 10 may be a ^{2 cm 2 · V -1 s -1} , may be ^{10 -2 cm 2 · V -1 s} -1 ~10 2 cm 2 · V -1 s -1 ..

The electron density of the first thin film 130 may be 1×10 ¹⁸ cm ⁻³ to 1×10 ²¹ cm ⁻³ , or may be 5×10 ¹⁸ cm ^{−3 to} 5×10 ²⁰ cm ^−3. It may be 1×10 ¹⁹ cm ⁻³ to 1×10 ²⁰ cm ⁻³ .

The first thin film 130 having such electron mobility and electron density is characterized by high conductivity and high electron transportability.

The electron mobility of the first thin film 130 can be obtained by a Hall measurement method, a time-of-flight (TOF) method, or the like. The electron density of the first thin film 130 can be obtained by an iodine titration method, a Hall measurement method, or the like.

The electron affinity of the first thin film 130 may be 2.0 eV to 4.0 eV, 2.2 eV to 3.5 eV, or 2.5 eV to 3.0 eV. When the electron affinity is 2.0 eV or more, the electron injection characteristics of the first thin film 130 are good, and the light emission efficiency of the organic EL element 100 is improved. In addition, when the electron affinity is 4.0 eV or less, it is easy to obtain sufficient light emission from the organic EL element 100. Due to such characteristics, by providing the first thin film 130, it is possible to enhance the electron injecting property with respect to the first electrode 120 in the organic EL element 100.

The ionization potential of the first thin film 130 may be 5.5 eV to 8.5 eV, 5.7 eV to 7.5 eV, or 5.9 eV to 7.0 eV. The first thin film 130 having such a large ionization potential has a high hole blocking effect and can selectively transport only electrons. Therefore, the hole blocking property with respect to the first electrode 120 can be improved by installing the first thin film 130.

The thickness of the first thin film 130 is not limited to this, but may be 10 μm or less, 2 μm or less, 1 nm or more, or 10 nm or more. ..

(Method of forming first thin film 130)
The first thin film 130 can be formed on the substrate 110 by a vapor deposition method using a target containing zinc (Zn) and silicon (Si), for example.

In the present application, “vapor deposition method” includes physical vapor deposition (PVD) method, PLD method, sputtering method, and vacuum deposition method, and after vaporizing a target raw material, the raw material is deposited on a substrate. This is a generic term for film forming methods.

The sputtering method includes a DC (direct current) sputtering method, a high frequency sputtering method, a helicon wave sputtering method, an ion beam sputtering method, a magnetron sputtering method and the like. By the sputtering method, a thin film can be formed relatively uniformly over a large area.

The target should just contain Zn and Si. Zn and Si may be contained in a single target, or may be separately contained in a plurality of targets. In the target, Zn and Si may be present as a metal or a metal oxide, respectively, or may be present as an alloy or a complex metal oxide. The metal oxide or mixed metal oxide may be crystalline or amorphous.

The target may contain one or more metal components selected from the group consisting of Sn, Ti, In, Ga, Nb, and Al, in addition to Zn and Si. Zn, Si and other metal components may be contained in a single target, or may be separately contained in a plurality of targets. In the target, Zn, Si and other metal components may be present as a metal or a metal oxide, respectively, or may be present as an alloy of two or more kinds of metals or a composite metal oxide. The metal oxide or mixed metal oxide may be crystalline or amorphous.

When a single target is used, the Zn/(Zn+Si) value in the target may be 0.30 to 0.95, 0.70 to 0.94, or 0.80 in terms of molar ratio. ˜0.92, or 0.85 to 0.90. When the single target contains one or more metal components selected from the group consisting of Sn, Ti, In, Ga, Nb, and Al in addition to Zn and Si, the content of these metal components is In terms of conversion, it is preferably 15 mol% or less, more preferably 10 mol% or less, and further preferably 5 mol% or less with respect to 100 mol% of the total of oxides of ZnO, SiO _2, and other metal components. In terms of oxide, the metal component is calculated as SnO ₂ , TiO ₂ , In ₂ O ₃ , Ga ₂ O ₃ , Nb ₂ O ₅ , or Al ₂ O ₃ . The composition analysis of the target can be performed by the XRF method or the like. The composition of the formed first thin film 130 may differ from the composition ratio of the target used.

When using a plurality of targets, for example, the first thin film 130 can be obtained by simultaneously sputtering a metal Si target and a ZnO target. Other combinations of a plurality of targets include a combination of a ZnO target and a SiO ₂ target, a combination of a plurality of targets containing ZnO and SiO _{2 and} having different ZnO ratios, a combination of a metal Zn target and a metal Si target, Examples thereof include a combination of a metal Zn target and a SiO ₂ target, and a combination of a target containing metal Zn or metal Si and a target containing ZnO and SiO ₂ .

When a plurality of targets are used at the same time, the first thin film 130 having a desired composition can be obtained by adjusting the power applied to each target.

When forming the first thin film 130, it is preferable that the substrate 110 is not “actively” heated when the first thin film 130 is amorphous or is in an amorphous state. .. This is because the first thin film 130 may not be likely to be amorphous when the temperature of the substrate 110 rises.

However, the substrate 110 may be “incidentally” heated by the sputtering process itself such as ion bombardment. In this case, how much the temperature of the substrate 110 rises depends on the sputtering conditions. The substrate 110 may be “aggressively” cooled to avoid an increase in the temperature of the substrate 110. It is preferable to form the first thin film 130 at a temperature of the substrate 110 of 70° C. or lower. The temperature of the substrate 110 may be 60° C. or lower, or 50° C. or lower.

The pressure of the sputtering gas (the pressure in the chamber of the sputtering apparatus) is preferably in the range of 0.05 Pa to 10 Pa, more preferably 0.1 Pa to 5 Pa, even more preferably 0.2 Pa to 3 Pa. Within this range, the pressure of the sputtering gas will not be too low, and the plasma will be stable. Further, since the pressure of the sputtering gas is not too high, the temperature rise of the substrate 110 due to the increased ion bombardment can be suppressed.

The sputtering gas used is not particularly limited. The sputtering gas may be an inert gas or a noble gas. It may contain oxygen. Examples of the inert gas include N ₂ gas. Examples of the rare gas include He (helium), Ne (neon), Ar (argon), Kr (krypton), and Xe (xenon). These may be used alone or in combination with other gas. Alternatively, the sputtering gas may be a reducing gas such as NO (nitrogen monoxide) or CO (carbon monoxide).

By the above method, the first thin film 130 can be formed on the first electrode 120.

(Step S130)
Next, gas pressure is applied to the first thin film 130.

Here, the value of the pressure applied to the first thin film 130 is, for example, in the range of 10 kPa to 1000 kPa, and may be atmospheric pressure (about 101 kPa), for example. When the pressure applied to the first thin film 130 is 10 kPa or more, the emission characteristics of the organic EL are improved and the power generation efficiency of the solar cell is improved. It is preferably 50 kPa or more, more preferably 80 kPa or more. If the pressure applied to the first thin film 130 is 1000 kPa or less, the light emitting characteristics of the organic EL and the power generation efficiency of the solar cell can be improved without using a large-scale high pressure applying device. It is preferably 500 kPa or less, more preferably 200 kPa or less.

Further, the gas may be air, nitrogen, oxygen, or the like.

The method of applying the pressure by the gas to the first thin film 130 is not particularly limited. For example, after performing step S120 in the chamber, the chamber may be opened and the substrate 110 may be removed from the chamber to apply pressure to the first thin film 130. In this case, the taken-out substrate 110 may be exposed to, for example, room temperature air, a nitrogen atmosphere, or an oxygen atmosphere.

Further, the temperature of the substrate may be raised when the pressure is applied. Specifically, 50°C to 300°C is preferable, 100°C to 200°C is more preferable, and 120°C to 180°C is further preferable.

(Step S140)
Next, the first additional layer 140 is disposed on the first thin film 130.

The first additional layer 140 may have at least one function of an electron injection layer, an electron transport layer, and a hole blocking layer.

Note that this step S140 is not an essential step and may be omitted if unnecessary. That is, the 1st additional layer 140 is a layer which can be installed arbitrarily. This is because the first thin film 130 formed in step S120 described above can also function as an electron injection layer, an electron transport layer, and/or a hole blocking layer.

However, when the first additional layer 140 is composed of an “electride layer” described later, the organic EL element 100 having better characteristics can be provided by disposing the first additional layer 140. It will be possible.

When disposing the first additional layer 140 as an electron transport layer, the first additional layer 140 is selected from materials having an electron transport property. As a film forming method of the electron transport layer, a conventional general film forming method can be used.

When the first additional layer 140 is arranged as an electron injection layer, the first additional layer 140 is selected from materials having an electron injection property.

The first additional layer 140 is, for example, one or more selected from the group consisting of lithium fluoride, cesium carbonate, sodium chloride, cesium fluoride, lithium oxide, barium oxide, barium carbonate, and 8-quinolinolatolithium. May be. As a film forming method of the electron injection layer, a conventional general film forming method can be used.

Moreover, when disposing the first additional layer 140 as a hole blocking layer, the first additional layer 140 is selected from materials having a hole blocking property.

The first additional layer 140 may be, for example, a material having a high HOMO level or the like. Alternatively, the first additional layer 140 may be an inorganic oxide, a metal oxide, or the like. As the first additional layer 140, for example, IGZO (In-Ga-Zn-O), ITO (In-Sn-O), ISZO (In-Si-Zn-O), IGO (In-Ga-O). , ITZO (In-Sn-Zn-O), IZO (In-Zn-O), and IHZO (In-Hf-Zn-O). As a film forming method for the hole blocking layer, a conventional general film forming method can be used.

Here, in particular, the first additional layer 140 is preferably composed of an electride of an amorphous oxide containing calcium atoms and aluminum atoms.

"Electride of amorphous oxide containing calcium atom and aluminum atom" means an amorphous solvent composed of an amorphous solvent composed of calcium atom, aluminum atom and oxygen atom and a solute of electrons. Means a solid substance. The electrons in the amorphous oxide act as anions. The electron may exist as a bipolaron. Bipolaron has two cages adjacent to each other, and electrons (solute) are included in each cage. However, the state of the electride of the amorphous oxide is not limited to the above, and two electrons (solute) may be included in one cage. Further, a plurality of these cages may be aggregated, and the aggregated cages can be regarded as microcrystals. Therefore, a state in which microcrystals are contained in amorphous is also regarded as amorphous in the present invention. The molar ratio (Ca/Al) of aluminum atoms to calcium atoms in the thin film of "amorphous oxide electride" is preferably in the range of 0.3 to 5.0, and in the range of 0.55 to 1.00. The range of 0.8 to 0.9 is more preferable, and the range of 0.84 to 0.86 is particularly preferable.

The composition of the “amorphous oxide electride” is preferably 12CaO·7Al ₂ O ₃ , but not limited to this, and examples thereof include the following compounds (1) to (4).
(1) A homomorphic compound in which some or all of the Ca atoms are replaced with metal atoms such as Sr, Mg, and/or Ba. For example, as a compound in which some or all of the Ca atoms are replaced with Sr, there is strontium aluminate Sr ₁₂ Al ₁₄ O _33. Cation Ca _12-x Sr _X Al ₁₄ O ₃₃ (x is an integer of 1 to 11; in the case of an average value, a number greater than 0 and less than 12) and the like.
(2) A homomorphic compound in which some or all of Al atoms are replaced with one or more atoms selected from the group consisting of Si, Ge, Ga, In, and B. For _example, like _{Ca 12 Al 10 Si 4 O 35} .
(3) Some of the metal atoms and/or non-metal atoms (excluding oxygen atoms) in 12CaO.7Al ₂ O ₃ (including the compounds of the above (1) and (2)) are Ti, V, One or more transition metal atoms or typical metal atoms selected from the group consisting of Cr, Mn, Fe, Co, Ni, and Cu, and one or more alkali metal atoms selected from the group consisting of Li, Na, and K, Or a homomorphic compound substituted with one or more rare earth atoms selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.
(4) A compound in which some or all of the free oxygen ions included in the cage are replaced with other anions. Examples of the other anion include anions such as H ⁻ , H ₂ ⁻ , H ^{2 −} , O ⁻ , O ₂ ⁻ , OH ⁻ , F ⁻ , Cl ⁻ , and S ^{2 −} , and nitrogen (N). There are anions, etc.
(5) A compound in which part of oxygen in the cage skeleton is replaced with nitrogen (N) or the like.

Hereinafter, the first additional layer 140 composed of such an electride of an amorphous oxide is particularly referred to as an "electride layer".

The electride layer can be used as an electron transport layer, an electron injection layer and/or a hole blocking layer.

The method for forming the electride layer is not particularly limited. The electride layer may be formed by, for example, a vapor deposition method. The electride layer may be deposited by heating the raw material in a vacuum of 10 ⁻³ Pa to 10 ⁻⁷ Pa, for example. Further, the electride layer may be formed by a sputtering method or the like.

The electride layer has high conductivity, a significantly high ionization potential, and a low work function. Therefore, by providing the electride layer, it becomes possible to manufacture the organic EL element 100 having better characteristics.

In this step S140, two or more layers of the electron injection layer, the electron transport layer, and the hole blocking layer may be arranged. For example, when the first additional layer 140 is a hole blocking layer, an electron transport layer and/or an electron injection layer is further disposed between the first additional layer 140 and the first thin film 130 in FIG. May be. Alternatively, when the first additional layer 140 is an electron injection layer, an electron transport layer and/or a hole blocking layer may be further arranged on the first additional layer 140 in FIG. Alternatively, when the first additional layer 140 is an electron transport layer, an electron injection layer is further disposed between the first thin film 130 and the first additional layer 140 in FIG. A hole blocking layer may be further disposed on the additional layer 140.

(Step S150)
Then, the organic light emitting layer 150 is disposed on the first additional layer 140.

The organic light emitting layer 150 is made of a material known as a light emitting material for an organic EL element.

The organic light emitting layer 150 includes, for example, epidridine, 2,5-bis[5,7-di-t-pentyl-2-benzoxazolyl]thiophene, 2,2′-(1,4-phenylenedivinylene)bis. Benzothiazole, 2,2'-(4,4'-biphenylene)bisbenzothiazole, 5-methyl-2-{2-[4-(5-methyl-2-benzoxazolyl)phenyl]vinyl}benzoxazole , 2,5-bis(5-methyl-2-benzoxazolyl)thiophene, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, perinone, 1,4-diphenylbutadiene, tetraphenylbutadiene, coumarin, acridine, stilbene , 2-(4-biphenyl)-6-phenylbenzoxazole, aluminum trisoxine, magnesium bisoxine, bis(benzo-8-quinolinol) zinc, bis(2-methyl-8-quinolinolato) aluminum oxide, indium trisoxine, Aluminum tris(5-methyloxine), lithium oxine, gallium trisoxine, calcium bis(5-chlorooxine), polyzinc-bis(8-hydroxy-5-quinolinolyl)methane, dilithium epindridione, zinc bisoxine, It may be 1,2-phthaloperinone, 1,2-naphthaloperinone or the like.

The organic light emitting layer 150 may be formed by a dry process such as a vapor deposition method or a transfer method. Alternatively, the organic light emitting layer 150 may be formed by a wet process such as a spin coating method, a spray coating method, or a gravure printing method.

Typically, the organic light emitting layer 150 has a thickness in the range of 1 nm to 100 nm. The organic light emitting layer 150 may also be used as the hole transport layer.

(Step S160)
Next, the second additional layer 160 is disposed on the organic light emitting layer 150. Note that this step S160 is not an essential step and may be omitted if unnecessary.

The second additional layer 160 has at least one function of a hole injection layer, a hole transport layer, and an electron block layer.

When the second additional layer 160 is formed as a hole injecting layer, the second additional layer 160 is selected from materials having a hole injecting property.

The second additional layer 160 may be, for example, CuPc and starburst amine. Alternatively, the hole injection layer is a metal oxide, for example, an oxide material containing one or more metals selected from the group consisting of molybdenum, tungsten, rhenium, vanadium, indium, tin, zinc, gallium, titanium and aluminum. Good.

The method for forming the hole injection layer is not particularly limited. The hole injection layer may be formed by a dry process such as a vapor deposition method or a transfer method. Alternatively, the hole injection layer may be formed by a wet process such as a spin coating method, a spray coating method, or a gravure printing method.

Typically, the hole injection layer thickness is in the range of 1 nm to 50 nm.

In addition, when the second additional layer 160 is formed as a hole transport layer, the second additional layer 160 is selected from materials having a hole transport property. As a film forming method of the hole transport layer, a conventional general film forming method can be used.

The hole transport layer may be, for example, an arylamine compound, an amine compound containing a carbazole group, an amine compound containing a fluorene derivative, or the like. Specifically, the hole transport layer includes 4,4′-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (α-NPD), N,N′-bis(3-methylphenyl)-( 1,1′-biphenyl)-4,4′-diamine (TPD), 2-TNATA, 4,4′,4″-tris(N-(3-methylphenyl)N-phenylamino)triphenylamine (MTDATA ), 4,4′-N,N′-dicarbazole biphenyl (CBP), spiro-NPD, spiro-TPD, spiro-TAD, TNB and the like.

The hole transport layer can be formed using a conventional general film forming process.

Typically, the hole transport layer thickness is in the range of 1 nm to 100 nm.

When the second additional layer 160 is formed as an electron blocking layer, the second additional layer 160 is selected from materials having an electron blocking property.

The electron block layer may be a material having a low LUMO level, for example. The electron block layer may be, for example, tris(phenylpyrazole)iridium (Tris(phenylpyrazole)iridium:Ir(ppz)3)) or the like.

In this step S160, two or more layers of the hole injection layer, the hole transport layer, and the electron block layer may be arranged. For example, when the second additional layer 160 is an electron blocking layer, a hole transport layer and/or a hole injection layer may be further disposed on the second additional layer 160 in FIG.

Alternatively, when the second additional layer 160 is a hole injection layer, in FIG. 2, a hole transport layer and/or an electron blocking layer is further disposed between the organic light emitting layer 150 and the second additional layer 160. Good. Alternatively, when the second additional layer 160 is a hole transport layer, in FIG. 2, an electron blocking layer is further disposed between the second additional layer 160 and the organic light emitting layer 150, and/or a second electron blocking layer is provided. A hole injection layer may be further disposed on the additional layer 160.

(Step S170)
Next, the second electrode 170 is disposed on the second additional layer 160.

A metal or metal oxide is usually used for the second electrode 170. The material used preferably has a work function of 4 eV or more. When the light extraction surface of the organic EL element 100 is on the second electrode 170 side, the second electrode 170 needs to be transparent.

The second electrode 170 may be a metallic material such as, for example, aluminum, silver, tin, gold, carbon, iron, cobalt, nickel, copper, zinc, tungsten, vanadium, or an alloy of the aforementioned metals. .. Alternatively, the second electrode 170 includes, for example, ITO, antimony oxide (Sb ₂ O ₃ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), IZO (Indium Zinc). _{oxide), AZO (ZnO-Al} 2 O 3: aluminum zinc oxide _{doped), GZO (ZnO-Ga 2} O 3: gallium zinc oxide doped), Nb-doped _TiO 2, Ta-doped TiO ₂ And a metal oxide such as IWZO (In ₂ O ₃ —WO ₃ —ZnO: indium oxide doped with tungsten trioxide and zinc oxide).

The method of forming the second electrode 170 is not particularly limited. The second electrode 170 may be formed by a known film forming technique such as a vapor deposition method, a sputtering method, or a coating method.

Typically, the second electrode 170 has a thickness in the range of 50 nm to 150 nm. When a metal material is used as the transparent electrode, the thickness of the second electrode 170 is preferably in the range of 2 nm to 50 nm.

Through the above steps, the organic EL device 100 as shown in FIG. 2 can be manufactured.

As described above, the organic EL element 100 manufactured by the first manufacturing method can exhibit better characteristics than the conventional organic EL element.

In the first manufacturing method, step S130 may be performed after step S140. That is, the pressure of the gas may be applied after the first additional layer 140 is placed on the first thin film 130. In this way, the first thin film 130 and the first additional layer 140 can be continuously formed, so that the productivity is improved.

In the above description, the characteristics of the organic EL element 100 are described by taking the case where the organic EL element 100 is manufactured by the first manufacturing method as an example. However, this is merely an example, and the inorganic EL element may be manufactured by the first manufacturing method. In this case, in step S150 described above, the inorganic light emitting layer is used instead of the organic light emitting layer 150. A material suitable for the inorganic EL element is used for the structure of each layer except the first thin film 130. As the inorganic light emitting layer, it is preferable that quantum dots of CdS or CdSe are dispersed.

(Method for manufacturing solar cell according to one embodiment of the present invention)
Next, with reference to FIGS. 3 and 4, a method for manufacturing a solar cell according to an embodiment of the present invention (hereinafter, referred to as “second manufacturing method”) will be described. In addition, here, the case where an organic solar cell is manufactured as a solar cell will be described as an example.

FIG. 3 schematically shows an example of the flow of the second manufacturing method. Further, FIG. 4 schematically shows a cross section of a solar cell manufactured by the second manufacturing method.

As shown in FIG. 3, the second manufacturing method is
(A) disposing the first electrode on the substrate (step S210),
(B) A metal oxide containing zinc (Zn) and oxygen (O) on the first electrode and further containing at least one of silicon (Si) and tin (Sn). Disposing the thin film of No. 1 (step S220),
(C) applying pressure to the substrate having the first electrode and the first thin film with a gas (step S230),
(D) disposing a first additional layer on the top of the first thin film (step S240),
(E) placing an organic photoelectric conversion layer on top of the first additional layer (step S250),
(F) disposing a second additional layer on the organic photoelectric conversion layer (step S260),
(G) disposing a second electrode on the second additional layer (step S270),
In this order.

As shown in FIG. 4, in the second manufacturing method, for example, on the substrate 210, the first electrode (cathode) 220, the first thin film 230, the first additional layer 240, the organic photoelectric conversion layer 250, The organic solar cell 200 including the second additional layer 260 and the second electrode (anode) 270 in this order is manufactured.

Here, from the comparison between FIG. 3 and FIG. 1, it is clear that the second manufacturing method has substantially the same configuration as the first manufacturing method. Further, from the comparison between FIG. 4 and FIG. 2, it is clear that the organic solar cell 200 manufactured by the second manufacturing method has substantially the same configuration as the organic EL element 100 manufactured by the first manufacturing method. is there.

More specifically, the second manufacturing method is different in that the organic photoelectric conversion layer 250 (see FIG. 4) is provided in place of the organic light emitting layer 150 (see FIG. 2) in step S250.

As the organic photoelectric conversion layer 250, a conventionally used one can be used. Further, as a method for forming the organic photoelectric conversion layer 250, a conventionally used method can be used.

Therefore, a person skilled in the art can easily understand each step of the second manufacturing method from the above description of the first manufacturing method. Therefore, detailed description of the second manufacturing method is omitted.

Also in the second manufacturing method, it is possible to manufacture an organic solar cell having better characteristics than ever before.

Furthermore, an inorganic solar cell may be manufactured by the second manufacturing method. In this case, in step S250 described above, the inorganic photoelectric conversion layer is used instead of the organic photoelectric conversion layer 250. Further, as the structure of each layer except the first thin film 230, a material suitable for an inorganic solar cell may be used.

Examples of the present invention will be described below.

(Example 1)
An organic EL device was manufactured by the following method.

A sputtering device was used for manufacturing the organic EL element. A chamber is connected to the sputtering apparatus, and the metal mask can be replaced within the chamber under a pressure of 10 kPa or less.

(Preparation of substrate to formation of first thin film)
First, the cathode was formed on the substrate. As the substrate, a non-alkali glass substrate having a length of 30 mm, a width of 30 mm and a thickness of 0.7 mm was used.

The cathode was formed by a sputtering method according to the following procedure.

The cleaned glass substrate and metal mask were placed in the chamber of the sputtering apparatus. Further, a target for cathode film formation was set in the chamber. A circular Al target with a diameter of 2 inches was used as the target. Power of 100 W was applied to the sputter cathode to form an Al film on the glass substrate.

The Al film was formed into a pattern with a thickness of 80 nm, a width of 1 mm, and a length of 18 mm by using a metal mask. The sputtering gas during film formation was Ar, and the pressure of the sputtering gas was 0.4 Pa.

Next, with the substrate kept in the chamber, a first thin film was formed on the cathode by a sputtering method. The first thin film was a metal oxide film containing Zn and Si.

A target having a composition of Zn:Si=80:20 in molar ratio was used. The distance between the target and the glass substrate during film formation was 100 mm. The sputtering gas during film formation was a mixed gas of Ar and O ₂ , and the pressure of the sputtering gas was 0.4 Pa. The flow rate of Ar was 39.9 sccm and the flow rate of O ₂ was 0.1 sccm. RF plasma power was 100W.

As a result, a metal oxide film containing Zn, Si and O was formed as the first thin film. The film thickness was 40 nm.

(First thin film exposed to air-patterning)
After that, the substrate was taken out of the sputtering apparatus, and the first layer was exposed to room temperature and atmospheric pressure. Moreover, the patterning process of the 1st thin film was implemented by the following method.

First, a photoresist (S9912G) was applied on the first thin film using a spin coater. Specifically, the photoresist was first applied at 500 rpm for 5 seconds, and then the photoresist was further applied at 4000 rpm for 20 seconds.

Next, the substrate was heated on a hot plate at 100° C. for 1 minute to bring the photoresist into close contact with the first thin film. Next, the photoresist was exposed using an exposure machine so that a desired pattern was obtained. After that, the photoresist was developed for 40 seconds using a developing solution (CD26: Shipley Co., Ltd.) to remove unnecessary photoresist portions.

Then, the substrate was heated again on a hot plate at 100° C. for 1 minute to re-adhere the photoresist to the first thin film.

Next, the substrate was immersed for 2.5 minutes in a 0.01 mol/liter aqueous solution of ethylenediaminetetraacetic acid sodium dihydrogen (manufactured by Kanto Kagaku) to etch the exposed first thin film. Then, the substrate was washed with pure water and dried by air blow.

Next, the substrate was dipped in a resist stripping solution 104 (manufactured by Tokyo Ohka) heated to 70° C. for 3 minutes, and further dipped in the resist stripping solution 104 at 25° C. for 1 minute to remove the resist. After that, the substrate was immersed in isopropyl alcohol for 1 minute to dry the substrate.

As a result, a patterned first thin film having a width of 1 mm and a length of 15 mm was formed on the Al film.

(Formation of first additional layer to formation of anode)
Next, the substrate was placed again in the chamber of the above-described sputtering apparatus, and the first additional layer was formed on the first thin film.

The first additional layer was an amorphous oxide electride layer containing Ca and Al, and was formed by a sputtering method. A crystalline C12A7 electride was used as a target. The film forming conditions were RF power of 100 W, Ar was used as a film forming gas, and the total pressure was 0.1 Pa. In the electride layer, the molar ratio of Ca atoms to Al atoms is 12:14. The film thickness was 5 nm.

Then, on top of the first additional layer, Ir(ppy) ₃ (tris(2-phenylpyridinato)iridium(III)) and CBP(4,4′-di(9H-carbazol-9-yl)). -1,1'-biphenyl) was co-evaporated to form an organic light emitting layer. Ir(ppy) ₃ in the layer was 6% by weight. The film thickness of the organic light emitting layer was 15 nm.

Next, a 50 nm hole transport layer (CBP) was formed by a vapor deposition method, and a 5 nm hole injection layer (molybdenum oxide) was further formed. These were patterned using a metal mask, and the size of the pattern was 1 mm×15 mm.

Further, a 20 nm Au layer was formed as an anode by a vapor deposition method. The Au layer was formed as a pattern having a width of 1 mm and a length of 20 mm.

As a result, an organic EL element having a light emitting region of 1 mm□ (hereinafter referred to as “sample 1”) was manufactured.

(Example 2)
An organic EL device was manufactured by the same method as in Example 1.

However, in this example 2, after the first thin film was exposed to the atmosphere and patterned, the substrate was placed in the chamber of the above-described sputtering apparatus and plasma treatment was performed.

Ar plasma was used as plasma. The Ar flow rate was 20 sccm, and the pressure was 0.6 Pa. The distance between the plasma cathode and the substrate was 100 mm. RF plasma power was 50W.

Then, in the same manner as in Example 1, the steps subsequent to the formation of the first additional layer were performed.

As a result, an organic EL element (hereinafter referred to as “Sample 2”) was manufactured.

(Example 3)
An organic EL device was manufactured by the same method as in Example 1.

However, in this example 3, after forming the first thin film, the first additional layer was formed without removing the substrate from the chamber, and after forming the first additional layer, exposure to the atmosphere was performed. After that, the substrate was placed again in the chamber, and the organic light emitting layer, the hole transport layer, the hole injection layer, and the anode were formed on the first additional layer. As a result, an organic EL element having a light emitting region of 1 mm□ (hereinafter referred to as “sample 3”) was manufactured. Here, the first thin film was patterned using a metal mask, and the size of the pattern was 1 mm×15 mm.

(Example 4)
An organic EL device was manufactured by the same method as in Example 1.

However, in this Example 4, after the formation of the first thin film, the first thin film was not exposed to air and patterned. That is, in Example 4, after forming the first thin film, the film formation of the first additional layer and the subsequent steps were performed without removing the substrate from the chamber.

As a result, an organic EL element (hereinafter referred to as “Sample 4”) was manufactured.

(Evaluation)
The above-mentioned samples were used to evaluate the light emission characteristics.

A current-voltage meter (Keithley 6430) was used for current-voltage characteristics, and a color luminance meter (BM-7, Topcon Corporation) was used for luminance evaluation. All measurements were performed in a Unico glove box equipped with a circulation refiner. The atmosphere in the glove box was nitrogen.

FIG. 5 shows the evaluation results of Examples 1 to 4. In FIG. 5, the horizontal axis is the applied voltage and the vertical axis is the emission brightness of the sample.

As shown in FIG. 5, in Sample 1, Sample 2, and Sample 3, the drive voltage required for equivalent light emission is lower than that in Sample 4, and it is understood that the light emission performance is improved. Particularly, in Sample 2, the light emission performance was significantly improved as compared with Sample 4.

In this way, it was confirmed that the characteristics of the device are improved by going through the step of applying pressure to the first thin film.

Further, the present application claims priority based on Japanese Patent Application No. 2015-234103 filed on November 30, 2015, and the entire contents of the Japanese application are incorporated herein by reference.

100 organic electroluminescence element 110 substrate 120 first electrode (cathode)
130 First Thin Film 140 First Additional Layer 150 Organic Light Emitting Layer 160 Second Additional Layer 170 Second Electrode (Anode)
200 organic solar cell 210 substrate 220 first electrode (cathode)
230 first thin film 240 first additional layer 250 organic photoelectric conversion layer 260 second additional layer 270 second electrode (anode)

Claims (11)

A method of manufacturing a photoelectric conversion element, comprising:
(1) disposing a first electrode on the substrate,
(2) A metal oxide containing zinc (Zn) and oxygen (O) and further containing at least one of silicon (Si) and tin (Sn) on the first electrode. Disposing a first thin film,
(3) applying a pressure to the substrate having the first electrode and the first thin film with a gas,
(4) disposing a photoelectric conversion layer that is a layer that converts an applied voltage into light or a layer that converts incident light into electric power, above the first thin film;
(5) disposing a second electrode on the photoelectric conversion layer,
Have a,
The method of the said (3) is implemented in the state which made the said board|substrate 50 to 300 degreeC . The method according to claim 1, wherein in the step (3), the pressure is applied by the atmosphere. The method of claim 1 or 2, wherein the pressure is atmospheric pressure. The step (2) above is performed in a chamber,
The method according to claim 1, wherein the step (3) is performed by opening the chamber. The method according to claim 1, wherein the first thin film has a molar ratio of Zn/(Zn+Si) of 0.3 to 0.95. The first thin film further contains one or more metal components selected from the group consisting of titanium (Ti), indium (In), gallium (Ga), niobium (Nb), and aluminum (Al). Item 6. A method according to any one of items 1 to 5. Furthermore, between the steps (3) and (4) above,
A step of providing a first additional layer on the first thin film, wherein the first additional layer is at least one of an electron injection layer, an electron transport layer, and a hole blocking layer. 7. The method according to any one of claims 1 to 6. The method of claim 7, wherein the first additional layer is composed of an electride of an amorphous oxide containing calcium atoms and aluminum atoms. Further, between the steps (4) and (5) above,
(6) Forming at least one of an electron block layer, a hole transport layer, and a hole injection layer on the photoelectric conversion layer,
The method according to claim 1, further comprising: The photoelectric conversion layer is an organic light emitting layer,
The method according to claim 1, wherein an organic electroluminescence element is manufactured as the photoelectric conversion element. The photoelectric conversion layer is an organic photoelectric conversion layer,
The method according to claim 1, wherein an organic solar cell is manufactured as the photoelectric conversion element.

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