KR20140065407A - Process for producing metallic particle assembly - Google Patents

Abstract

A method for producing a metal-based grain aggregate in which 30 or more metal-based particles are arranged two-dimensionally apart from each other, comprising the steps of: applying an average height growth rate of less than 1 nm / min on a substrate whose temperature has been adjusted within a range of 100 deg. C to 450 deg. A method of manufacturing a metal-based grain aggregate including a step of growing metal-based grains. According to the above production method, a metal-based grain aggregate composed of metal-based particles having an average particle diameter of 200 nm to 1600 nm, an average height of 55 nm to 500 nm, and an aspect ratio of 1 to 8 defined by a ratio of an average particle diameter to an average height Can be manufactured.

Description

TECHNICAL FIELD [0001] The present invention relates to a process for producing a metal-

The present invention relates to a method for improving the light emitting efficiency of a light emitting element (an organic EL (electroluminescence) element, an inorganic EL element, an inorganic LED (light emitting diode) element, a quantum dot light emitting element, Which is a plasmon material (plasmonic material) useful for improving the conversion efficiency of a metal-based particle aggregate.

It has been conventionally known that when the metal particles are miniaturized to nanosize, a function that has not been seen in the bulk state is developed, and among these, application is expected to be "localized plasmon resonance". Plasmon refers to a dense wave of free electrons generated by the collective vibration of free electrons in a metal nanostructure.

In recent years, the technical field of handling the plasmons is called " plasmonics " and has attracted a great deal of attention, and vigorous research has been conducted. Such studies have been conducted to improve the luminous efficiency of light emitting devices using local plasmon resonance phenomenon of metal nanoparticles, And for improving the conversion efficiency of photoelectric conversion elements (solar cell elements, etc.).

For example, Japanese Laid-Open Patent Application No. 2007-139540 (Patent Document 1), Japanese Patent Application Laid-Open No. 08-271431 (Patent Document 2), and International Publication No. 2005/033335 (Patent Document 3) Thereby increasing the fluorescence. In addition, T. Fukuura and M. Kawasaki, "Long Range Enhancement of Molecular Fluorescence by Closely Submicroscale Ag Islands", e-Journal of Surface Science and Nanotechnology, 2009, 7, 653 (non-patent document 1) A study on local plasmon resonance by silver nanoparticles is shown.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-139540 Patent Document 2: Japanese Patent Application Laid-Open No. 08-271431 Patent Document 3: International Publication No. 2005/033335

Non-Patent Document 1: T. Fukuura and M. Kawasaki, "Long Range Enhancement of Molecular Fluorescence by Closely Submicroscale Ag Islands", e-Journal of Surface Science and Nanotechnology, 2009, 7, 653

Conventional luminescent enhancement using the local plasmon resonance phenomenon of metal nanoparticles has the following problems. That is, factors of the luminescent enhancing action by the metal nanoparticles include (1) the generation of localized plasmons in the metal nanoparticles, thereby enhancing the electric field near the particle (first factor) and (2) The oscillation mode of the free electrons in the metal nanoparticles is excited, whereby an organic dipole having a luminescence greater than that of the excited molecule is generated in the metal nanoparticles, thereby increasing the quantum efficiency of light emission itself (second factor) In order to effectively cause the luminescent organic dipole in the second factor, which is a larger factor, to occur in the metal nanoparticles, the distance between the metal nanoparticle and the excited molecule (fluorescent substance or the like) The energy transfer by the Dexter mechanism, which is a direct movement of the Dexter mechanism, does not take place, Nm). This is because the luminescence of the luminescent organic dipole is based on the theory of energy transfer of the stirrer (see Non-Patent Document 1).

Generally, in the range of 1 nm to 10 nm, the closer the distance between the metal nanoparticles and the excited molecules is, the more easily the luminous organic dipole is generated, and the luminescence enhancing effect is enhanced. On the other hand, , The local luminous intensity enhancement effect is gradually weakened due to the fact that the local plasmon resonance is not effectively influenced, and when the energy movement of the Zruster mechanism is exceeded (generally, the distance is about 10 nm or more) There was no. In the luminescence enhancing method described in the above Patent Documents 1 to 3, the distance between the effective metal nanoparticles and the molecules to be excited is 10 nm or less in order to obtain an effective luminescent enhancing effect.

Thus, there has been a fundamental problem that, in the local plasmon resonance using conventional metal nanoparticles, the action range is limited within a very narrow range from the surface of the metal nanoparticles to 10 nm or less. This problem inevitably brings about the problem that almost no improvement effect is shown in an attempt to improve the light emitting efficiency and the conversion efficiency by using the local plasmon resonance by the metal nanoparticles in the light emitting element or the photoelectric conversion element. That is, the light emitting element and the photoelectric conversion element usually have an active layer (for example, a light emitting layer of a light emitting element or a light absorbing layer of a photoelectric conversion element) having a thickness of several tens nm or more. However, if metal nanoparticles are arranged The direct enhancement effect by the local plasmon resonance can be obtained only in a very small part of the active layer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a method of manufacturing a plasmon material (plasmonic material) useful as an enhancing element of various optical elements including a light emitting element, a photoelectric conversion element Method.

In the above Patent Document 1 (paragraphs 0010 to 0011), a theoretical explanation is given on the relationship between the luminescent enhancement due to the localized plasmon resonance and the particle diameter of the metal nanoparticles. According to this, a completely spherical In the case of using silver particles, in theory, the luminous efficiency [phi] is approximately 1, but in practice these silver particles exhibit little luminescent enhancing action. Such a large-sized silver particle exhibits little luminescent enhancing action because the surface free electrons in the silver particles are so large that it is difficult to generate a dipole-type localized plasmon, which is seen as ordinary nanoparticles (relatively small-diameter nanoparticles) . However, if it is possible to effectively excite a large number of surface free electrons contained in the large nano-particles effectively as plasmons, it is considered that the enhancing effect by the plasmons can be dramatically improved.

As a result of intensive studies, the inventors of the present invention have found that a metal-based grain aggregate obtained by growing a specified number or more of metal-based grains on a substrate under predetermined conditions is generally considered to have a small luminescence enhancing effect as described above (A range in which the enhancement effect by plasmons is exerted) exhibits extremely strong plasmon resonance and remarkably elongated plasmon resonance due to having a specific shape and the like despite its relatively large particle diameter.

That is, the present invention includes the following.

[1] A method for producing a metal-based grain aggregate in which 30 or more metal-based grains are arranged two-dimensionally apart from each other,

Comprising the step of growing metal-based particles at an average height growth rate of less than 1 nm / min on a substrate whose temperature has been adjusted within a range of 100 占 폚 to 450 占 폚.

[2] In the step of growing the metal-based particles, the metal-based particles preferably have an average height growth rate of less than 1 nm / min and an average height growth rate of less than 5 nm / min Wherein the metal particles are grown at an average particle diameter growth rate.

[3] The metal particle constituting the metal-based particle aggregate preferably has an average particle diameter in the range of 200 nm to 1600 nm, an average height in the range of 55 nm to 500 nm, and an average particle diameter (1) in which the aspect ratio defined by the ratio is in the range of 1 to 8, and the average distance from the adjacent metal particles (hereinafter also referred to as the average particle distance) is in the range of 1 nm to 150 nm. Or the metal-based grain aggregate according to [2].

[4] The metallic particle constituting the metal-based particle aggregate preferably has an average particle diameter in the range of 200 nm to 1600 nm, an average height in the range of 55 nm to 500 nm, The aspect ratio defined by the ratio is in the range of 1 to 8,

The metal-based particle aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particle in the absorption spectrum in the visible light region, (1) or (2) in which the maximum wavelength of the peak on the longest wavelength side shifts to the short wavelength side in the range of 30 nm to 500 nm, as compared with the reference metal-based particle aggregate (X) Based on the total mass of the metal-based particles.

[5] The metallic particle constituting the metal-based particle aggregate preferably has an average particle diameter within the range of 200 nm to 1600 nm, an average height within the range of 55 nm to 500 nm, and an average particle diameter The aspect ratio defined by the ratio is in the range of 1 to 8,

The metal-based particle aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particle in the absorption spectrum in the visible light region, (1) or (2) where the absorbance at the maximum wavelength of the peak on the longest wavelength side is higher than that of the reference metal-based particle aggregate (Y) Based on the total mass of the metal-based particles.

[6] The method for producing the metal-based grain aggregate according to any one of [1] to [5], wherein the temperature of the substrate in the step of growing the metal-based particles is within a range of 250 ° C. to 350 ° C.

[7] The method for producing a metal-based grain aggregate according to any one of [1] to [6], wherein the step of growing the metal-based particles is performed under a pressure of 6 Pa or more.

[8] The method for producing a metal-based grain aggregate according to [7], wherein the step of growing metal-based particles is performed at a pressure of 10 Pa or more.

[9] The method for producing a metal-based grain aggregate according to any one of [1] to [8], wherein the step of growing the metal-based particles is performed by a sputtering method.

[10] The method for producing a metal-based grain aggregate according to [9], wherein the step of growing the metal-based particles is performed by the DC sputtering method.

[11] The method for producing a metal-based grain aggregate according to [10], wherein the step of growing metal-based particles is performed by a direct current argon ion sputtering method.

[12] The method for producing a metal-based grain aggregate according to any one of [1] to [11], wherein the metal-based particles constituting the metal-based grain aggregate are made of a noble metal.

[13] The method for producing the metal-based grain aggregate according to [12], wherein the metal-based particles constituting the metal-based grain aggregate are silver.

According to the production method of the present invention, a thin film of a metal-based grain aggregate composed of metal-based particles having a predetermined shape (average particle diameter, average height and aspect ratio) and a predetermined distance between average particles can be obtained with good controllability. The metal particle aggregate obtained according to the production method of the present invention is extremely useful as an enhancing element of an optical element including a light emitting element, a photoelectric conversion element (solar cell element, etc.), and the luminous efficiency and conversion efficiency of the applied optical element .

1 is an SEM image (10000 times and 50000 times scale) when viewed from directly above the thin film of the metal-based grain aggregate obtained in Example 1. Fig.
Fig. 2 is an AFM image of the metal-based particle aggregate thin film obtained in Example 1. Fig.
3 is an AFM image of the silver film obtained in Comparative Example 1. Fig.
4 is an absorption spectrum of the metal-based particle aggregate thin film obtained in Example 1 and the silver thin film obtained in Comparative Example 1. Fig.
Fig. 5 is a schematic flow chart showing a method for producing a reference metal-based grain aggregate.
6 is an SEM image (20000 times and 50000 times scale) when the reference metal particle aggregate thin film in the reference metal particle aggregate thin film laminate substrate is viewed from above.
7 is a view for explaining a light absorption spectrum measuring method using an objective lens (100 times) of a microscope.
8 is an absorption spectrum of the metal-based particle-aggregate thin film laminated substrate obtained in Example 1, which was measured according to a method using an objective lens (100 times) of a microscope.
9 is an SEM image (10,000 times scale) when the metal-based particle aggregate thin film on the metal-based particle assembly thin film laminated substrate obtained in Comparative Example 4-1 is viewed from directly above.
10 is an AFM image of the metal-based particle aggregate thin film in the metal-based particle-aggregate thin film laminated substrate obtained in Comparative Example 4-1.
11 is an absorption spectrum of the thin film laminate substrate of the metal-based grain aggregated body obtained in Example 4-1 and Comparative Example 4-1 according to the measurement method using an integral spherical spectrophotometer.
12 is an absorption spectrum according to a measurement method using an objective lens (100 times) of a microscope of the thin film laminate of the metal-based grain-particle assembly obtained in Comparative Example 4-1.
13 is an SEM image (10000 times and 50000 times scale) when the metal-based particle aggregate thin film on the metal-based particle assembly thin film laminated substrate obtained in Comparative Example 10-1 is viewed from directly above.
14 is an AFM image of a metal-based particle aggregate thin film on the metal-based particle-aggregate thin film laminated substrate obtained in Comparative Example 10-1.
15 is an absorption spectrum of the metal-based grain-particle assembly thin-film laminated substrate obtained in Comparative Example 10-1.
FIG. 16A is a schematic view showing a measurement system of the light emission spectrum of a photoexcitation light emitting element, and FIG. 16B is a schematic cross-sectional view showing a photoexcitation light emitting element having a metal particle aggregate film and an insulating layer.
17 is a view for comparing the light emission enhancement effect of the photoexcitation light emitting device of Examples 4-1 to 4-6 and the light emission enhancement effect of the photoexcitation light emission device of Comparative Examples 4-1 to 4-6 .
FIG. 18 shows the light emission enhancing effect of the photoexcitation light emitting devices of Examples 5-1 to 5-5 and the light emission enhancing effect of the photoexcitation light emitting devices of Comparative Examples 6-1 to 6-5 and Comparative Examples 10-1 to 10-5 And the light emission enhancing effect in the light emitting layer.
19 is a view for comparing the light emission enhancement effect of the photoexcitation light emitting device of Examples 6-1 to 6-3 with the light emission enhancement effect of the photoexcitation light emission device of Comparative Examples 8-1 to 8-3 .

≪ Process for producing metal-based grain aggregate &

The method for producing the metal-based grain aggregate of the present invention includes a step of growing metal-based particles at a very low speed (hereinafter also referred to as a grain growing step) on a substrate adjusted to a predetermined temperature. According to the manufacturing method including such a grain growing step, 30 or more metal-based particles are two-dimensionally spaced apart from each other, and the metal-based particles have a shape within a predetermined range (average particle diameter 200 nm to 1600 nm, 55 nm to 500 nm and an aspect ratio of 1 to 8), and more preferably, a thin film of a metal-based grain aggregate having an average particle distance (1 nm to 150 nm) within a predetermined range.

In the grain growth process, the rate of growth of the metal-based particles on the substrate is less than 1 nm / min, preferably 0.5 nm / min or less, at the average height growth rate. The average height growth rate referred to herein may also be referred to as an average deposition rate or an average thickness growth rate of metal-based particles,

Average height of metal-based particles / metal-based particle growth time (supply time of metal-based materials)

. The definition of " average height of metal-based particles "

The temperature of the substrate in the grain growth process is in the range of 100 to 450 占 폚, preferably 200 to 450 占 폚, more preferably 250 to 350 占 폚, and more preferably 300 占 폚 or near 300 DEG C +/- 10 DEG C).

In the manufacturing method of the present invention, which includes a grain growth step of growing metal-based grains at an average height growth rate of less than 1 nm / min on a substrate whose temperature has been adjusted within a range of 100 ° C to 450 ° C, A plurality of island-like structures made of the supplied metal-based materials are formed, and the island-like structures are supplied with additional metal-based materials and coalesced with surrounding island-shaped structures while greatly growing. As a result, A metal-based grain aggregate in which particles having a relatively large mean particle diameter are densely arranged is formed while being completely separated. Therefore, it becomes possible to produce a metal-based grain aggregate composed of metal-based particles controlled to have a shape within a predetermined range (average particle diameter, average height and aspect ratio), more preferably a distance between average particles within a predetermined range.

Further, by adjusting the average height growth rate, the substrate temperature and / or the growth time of the metal-based particles (the supply time of the metal-based material), the average particle diameter, the average height, the aspect ratio, and / or the average It is also possible to control the distance between particles within a predetermined range.

Further, according to the manufacturing method of the present invention, various conditions other than the substrate temperature and the average height growth rate in the grain growth step can be selected relatively freely, so that the metal-based grain aggregate thin film of a desired size can be efficiently As shown in Fig.

When the average height growth rate is 1 nm / min or more, or when the substrate temperature is lower than 100 deg. C or higher than 450 deg. C, a continuum is formed with the surrounding island structure before the island structure grows large, It is impossible to obtain a metal-based aggregate composed of metal-based particles having a large particle diameter or a metal-based aggregate composed of metal-based particles having a desired shape (for example, the average height and the distance between the average particles and the aspect ratio deviate from the desired range).

The pressure at which the metal-based particles are grown (the pressure in the apparatus chamber) is not particularly limited as long as it is a pressure capable of grain growth, but is usually lower than atmospheric pressure. The lower limit of the pressure is not particularly limited, but is preferably 6 Pa or more, more preferably 10 Pa or more, and further preferably 30 Pa or more because it is easy to adjust the average height growth rate within the above range.

A specific method of growing the metal-based particles on the substrate is not particularly limited as long as the method can grow the particles at an average height growth rate of less than 1 nm / minute, and examples thereof include a vapor deposition method such as a sputtering method and a vacuum deposition method. Among the sputtering methods, it is preferable to use the direct current (DC) sputtering method because the metal-based grain aggregate can be relatively easily grown and the average height growth rate of less than 1 nm / minute can be easily maintained. The sputtering method is not particularly limited, and a direct current argon ion sputtering method in which argon ions generated by an ion gun or a plasma discharge are accelerated by an electric field to irradiate a target can be used. Various other conditions such as a current value, a voltage value, and a distance between the substrate and the target in the sputtering method are appropriately adjusted so that the grain growth is carried out at an average height growth rate of less than 1 nm / min.

In order to controllably obtain a thin film of a metal-based grain aggregate composed of metal-based particles having a shape within a predetermined range (average particle diameter, average height and aspect ratio), more preferably a distance between average particles within a predetermined range, It is preferable to set the average height growth rate to less than 1 nm / min. In addition, when the average height growth rate is less than 1 nm / min, The speed is less than 5 nm. The average particle diameter growth rate is more preferably 1 nm / min or less. The average particle diameter growth rate refers to the following formula:

Average particle diameter of metal-based particles / metal-based particle growth time (supply time of metal-based material)

. The definition of " average particle diameter of metal-based particles "

The growth time (supply time of the metal-based material) of the metal-based particles in the grain growth process is at least the time for the metal-based particles carried on the substrate to reach a shape within a predetermined range, more preferably a distance between average particles within a predetermined range , And also the shape within the predetermined range, less than the time which starts to deviate from the distance between the average particles. For example, even if the grain growth is carried out at the average height growth rate and the substrate temperature within the predetermined range, if the growth time is extremely excessively long, the amount of the metal-based material to be supported is excessively large and aggregates of the metal- Or the average particle diameter or average height of the metal-based particles becomes excessively large.

Therefore, it is necessary to set the growth time of the metal-based particles to an appropriate time (to stop the particle growth step at an appropriate time), but such setting of the time can be made, for example, And the relationship between the shape of the metal-based particles and the distance between the average particles in the obtained metal-based particle aggregate. Alternatively, a preliminary experiment may be carried out in advance to obtain the time until the thin film made of the metal-based material grown on the substrate exhibits conductivity (that is, the time when the thin film becomes a continuous film instead of the metal-based particle aggregate film) The particle growth process may be stopped.

When the metal particles constituting the metal-based particle aggregate (metal-based material supplied onto the substrate) are nanoparticles or aggregates thereof, the plasmon resonance peaks appearing in the ultraviolet to visible region in the absorption spectrum measurement according to the absorption spectrophotometry (Also referred to as a peak), and examples thereof include noble metals such as gold, silver, copper, platinum and palladium, metals such as aluminum and tantalum; An alloy containing the noble metal or metal; And metal compounds (such as metal oxides and metal salts) containing the noble metal or metal. Of these, noble metals such as gold, silver, copper, platinum and palladium are preferable, and silver is more preferable from the viewpoints of low cost and low absorption (the imaginary part of the dielectric function is small at visible light wavelength). It is preferable that the kind of the metal-based material is appropriately selected depending on the kind of the optical element to which the metal-based grain aggregate is applied as the enhancing element.

Here, in the thin film of the metal-based particle aggregate formed on the substrate obtained according to the production method of the present invention, the metal-based particles are electrically insulated from each other, that is, between adjacent metal- Non-conductive as a thin film). Since electrons can be transmitted between some or all of the metal-based particles, the plasmon peak loses sharpness, is close to the absorption spectrum of the bulk metal, and high plasmon resonance is not obtained. Therefore, it is preferable that the metal-based particles are reliably spaced apart from each other, and that no conductive material intervenes between the metal-based particles.

From the viewpoint of ensuring the non-conductivity of the metal-based particle aggregate thin film, it is preferable to use a non-conductive substrate as the substrate. As the non-conductive substrate, glass, various inorganic insulating materials (SiO ₂ , ZrO ₂ , mica, etc.), and various plastic materials can be used. In particular, when applied to, for example, a light emitting device, light can be taken out from the surface of the substrate (the surface opposite to the surface of the metal-based particle aggregate thin film), so it is preferable to use a substrate having translucency, Is more preferable.

The surface of the substrate on which the metal-based particles are grown is preferably as smooth as possible, and more preferably smooth at an atomic level such as, for example, the surface of mica. As the surface of the substrate becomes smoother, the growing metal particles tend to coalesce with other surrounding adjacent metal particles due to thermal energy received from the substrate, so that a film made of metal particles of a larger size tends to be easily obtained .

Further, the manufacturing method of the present invention may include a step of forming an insulating layer on the thin film surface of the metal-based grain aggregate, as described in detail later.

≪ Metal-based particle aggregate &

As described above, according to the production method of the present invention, 30 or more metal-based particles are two-dimensionally arranged apart from each other, and the average particle diameter of the metal-based particles is within a range of 200 nm to 1600 nm, Having an aspect ratio within a range of 1 to 8, which is defined as a ratio of an average particle diameter to an average height within a range of 55 nm to 500 nm, can be obtained with good controllability.

The metal-based grain aggregate obtained by the production method according to the present invention further has any of the following characteristics.

[I] The metal-based particles constituting the metal-based particle aggregate are arranged such that the average distance (distance between the average particles) to the adjacent metal-based particles is in the range of 1 nm to 150 nm.

[Ii] The metal-based grain aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particle in the absorption spectrum in the visible light region, The maximum wavelength of the peak on the longest wavelength side is shifted to the short wavelength side in the range of 30 nm to 500 nm as compared with the reference metal-based particle aggregate (X)

[Iii] The metal-based grain aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particles in the light absorption spectrum in the visible light region, The absorbance at the maximum wavelength of the peak on the longest wavelength side is higher than that of the reference metal-based particle aggregate (Y) arranged so as to fall within the range of from 2 to 2 mu m.

In the present specification, the mean particle diameter and average height of the metal-based particle aggregate are " the same as the reference metal-based particle aggregate (X) or (Y) " And the difference is within ± 10 nm.

(Metal-based grain aggregate [i])

The metal-based grain aggregate (metal-based grain aggregate [i]) having the feature [i] described above is very advantageous in the following respects.

(1) Since it exhibits extremely strong plasmon resonance, when applied to a light emitting device, a stronger luminescence enhancing effect can be obtained as compared with the case of using a conventional plasmon material, and thereby the luminescence efficiency can be drastically increased . Further, when applied to a photoelectric conversion element, the conversion efficiency can be dramatically increased. The strength of the plasmon resonance represented by the metal-based grain aggregate [i] is not a simple sum of local plasmon resonance represented by the individual metal-based particles at a specific wavelength, but is more than that. That is, since 30 or more metal particles having a predetermined shape are densely arranged at the predetermined intervals, the individual metal particles interact with each other, and an extremely strong plasmon resonance is expressed. It is considered that this is expressed by the interaction between the local plasmons of the metal-based particles.

Generally, a plasmon material exhibits a plasmon peak as a peak in the ultraviolet to visible region when the absorption spectrum is measured by the absorption spectrophotometry. From the magnitude of the absorbance at the maximum wavelength of the plasmon peak, The intensity of the plasmon resonance can be evaluated in an abbreviated manner. However, when the absorption spectrum of the metal-based particle aggregate [i] formed on the glass substrate is measured, the absorbance at the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light range 1 or more, or more than 1.5, or even 2 or so.

The absorption spectrum of the metal-based grain aggregate is measured by a spectrophotometric method using a sample formed on a glass substrate as a measurement sample. Concretely, the absorption spectrum is obtained by irradiating incident light in the ultraviolet to visible light region from the direction perpendicular to the substrate surface, on the back side (opposite to the metal-based particle aggregate thin film) of the glass substrate on which the metal- The intensity (I) of the transmitted light in the entire direction transmitted to the aggregate thin film side and the intensity (I) of the transmitted light from the direction perpendicular to the plane of the substrate on which the metal- Is obtained by irradiating the same incident light as before and measuring the intensity (I ₀ ) of the transmitted light in the entire direction transmitted from the opposite side of the incident surface by using an integral spherical spectrophotometer. At this time, the absorbance, which is the ordinate of the absorption spectrum,

Absorbance = -log ₁₀ (I / I ₀ )

Respectively.

(2) the range of action of plasmon resonance (the range of enhancement effect by plasmon) is remarkably elongated. It is also believed that this elongation is also manifested by the interaction between the internally-generated plasmons of the metal-based particles formed by densely arranging the metal-based particles of 30 or more predetermined shapes at predetermined intervals. According to the metal-based grain aggregate [i], the action range of plasmon resonance, which has been conventionally limited within the range of the approximate Louverst distance (about 10 nm or less), can be extended to, for example, several hundreds nm.

The elongation of the action range of plasmon resonance as described above is very advantageous for the enhancement of optical elements such as light emitting elements and photoelectric conversion elements (solar electronic elements, etc.). In other words, it is possible to increase the entirety of the active layer (light-emitting layer in the light-emitting element or light-absorbing layer in the photoelectric conversion element) having a thickness of usually several tens nm or more, The luminous efficiency (luminous efficiency, conversion efficiency, etc.) of the optical element can be remarkably improved.

In the conventional plasmon material, it is necessary to arrange the plasmon material so that the distance from the active layer is within the range of the Stokes distance. According to the metal-based particle aggregate [i], however, For example, 20 nm), and even if it is disposed at a position away from a few hundred nanometers, an enhancing effect by plasmon resonance can be obtained. This means that, for example, in the case of a light-emitting element, it becomes possible to dispose a plasmon material (metal-based particle aggregate) in the vicinity of the light-extracting surface, which is considerably distant from the light-emitting layer. In the light emitting device using the conventional plasmon material, it is necessary to arrange the plasmon material in the very vicinity of the light emitting layer, and since the distance between the plasmon material and the light emitting surface is large, , Most of the light is totally reflected at the interface between the various light emitting device constituent layers passing therethrough, and the light extraction efficiency may be very small.

Although the metal-based particle aggregate [i] alone uses relatively large metal-based particles in which the dipole-type localized plasmons are hardly generated in the visible light region, such large metal-based particles (having a predetermined shape It is possible to effectively excite a large number of surface free electrons contained in the large metal-based particles effectively as a plasmon, and to achieve remarkably strong plasmon resonance and plasmon resonance Thereby realizing a remarkable elongation of the working range of the present invention.

Further, the metal-based grain aggregate [i] has the following advantageous effects owing to the structure in which a specified number or more of relatively large metal-based particles having a specific shape are two-dimensionally spaced apart at specific intervals .

(3) In the absorption spectrum in the visible light region, the maximum wavelength of the plasmon peak may exhibit a peculiar shift, depending on the average particle diameter of the metal-based particles and the distance between the average particles. Concretely, the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region shifts (blue shifts) to the short wavelength side as the average particle diameter of the metal-based particles is increased by keeping the distance between the average particles constant. Likewise, when the average particle diameter of the large metal-based particles is made constant and the distance between the average particles is made small (when the metal-based particles are densely arranged), the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region becomes shorter Shift. This peculiar phenomenon is contrary to the generally accepted scattering theory for plasmon materials (according to this theory, the maximum wavelength of the plasmon peak shifts to the longer wavelength side (red shift) when the particle diameter becomes large).

The above-mentioned peculiar blue shift also has a structure in which the metal-based grain aggregate [i] has a structure in which large metal-based grains are densely arranged at specific intervals, and thus the interaction between the internally- . The metal-based grain aggregate [i] (in a state of being laminated on a glass substrate) has a maximum absorption spectrum in the absorption spectrum in the visible light region measured according to the absorption spectrophotometry, depending on the shape of the metal- The plasmon peak can exhibit a maximum wavelength in a wavelength range of 350 nm to 550 nm, for example. In addition, the metal-based grain aggregate [i] has a grain size of about 30 nm to about 500 nm (for example, about 30 nm to about 250 nm), which is typically about 30 nm to about 500 nm in comparison with the case where the metal- Blue shift can be generated.

Such a metal-based grain aggregate in which the maximum wavelength of the plasmon peak is blue-shifted as compared with the conventional one is very advantageous, for example, in the following points. In other words, it is strongly desired to realize a blue light emitting material (particularly a blue light emitting material) that exhibits a high light emitting efficiency. However, it is difficult in the present situation to develop such a material that can withstand practical use sufficiently, For example, by applying the metal particle aggregate [i] having a plasmon peak in a blue wavelength region to a light emitting element as an enhancing element, even when a blue light emitting material having a relatively low light emitting efficiency is used, the light emitting efficiency can be increased to a sufficient level . In addition, when applied to a photoelectric conversion element (solar cell element or the like), for example, by blue-shifting the resonance wavelength, it is possible to effectively use the wavelength region that was not available in the active layer itself, and the conversion efficiency can be improved.

Next, the specific constitution of the metal-based grain aggregate [i] will be described in more detail.

The average particle diameter of the metal-based particles is in the range of 200 nm to 1600 nm and is preferably 200 nm to 1200 nm, more preferably 250 nm to 500 nm, in order to effectively obtain the effects (1) to (3) , More preferably in the range of 300 nm to 500 nm. The average particle diameter of the metal-based particles is desirably appropriately selected depending on the kind of the optical element to which the metal-based particle aggregate is applied as the enhancing element and the kind of the material constituting the metal-based particle.

It should be noted here that, as described above, large metal particles having an average particle diameter of 500 nm, for example, are rarely recognized by the local plasmon as an enhancing effect. On the other hand, the metal-based grain aggregate [i] has a remarkably strong plasmon resonance and remarkable elongation of the action range of plasmon resonance, (3).

The average particle diameter of the metal-based particles means that 10 particles are randomly selected in an SEM observation image just above a thin film of the metal-based particle aggregate on which the metal-based particles are two-dimensionally arranged, randomly tangent diameters within each particle are set to 5 (The straight line having a tangential diameter can pass only through the interior of the particle, one of which passes through only the inside of the particle and is regarded as a straight line drawn the longest), and the average value is set to the particle diameter of each particle , The average value of the diameters of the ten selected particles. The tangential diameter is defined as a line connecting the contour (projection) of the particle with the interval between two parallel lines touching it (Nikken Kogyo Shinbunsha "Particle Measurement Technology", 1994, page 5) .

The average height of the metal-based particles is in the range of 55 nm to 500 nm and is preferably in the range of 55 nm to 300 nm, more preferably in the range of 70 nm to 150 nm, in order to effectively obtain the effects (1) to (3) It is mine. The average height of the metal-based particles is an average value of 10 measured values when 10 particles are randomly selected and the height of these 10 particles is measured in the AFM observation image of the thin film of the metal-based particle aggregate.

The aspect ratio of the metal-based particles is in the range of 1 to 8, and it is preferable that the aspect ratio is appropriately selected depending on the kind of the optical element to which the metal-based particle aggregate is applied as the enhancing element. For example, when used as an enhancing element of a light-emitting element, it is preferable that the metal-based particles have a flat shape. In this case, in order to obtain a higher enhancing effect, the aspect ratio is preferably 2 to 8, Is more preferable. On the other hand, when used as an enhancing element of a photoelectric conversion element, in order to obtain a higher enhancing effect, metal-based particles tend to be closer to a perfectly spherical shape. The aspect ratio of the metal-based particles is defined as a ratio (average particle diameter / average height) of the average particle diameter to the average height.

Although it is preferable that the metal-based particles have a smooth curved surface from the viewpoint of exciting the highly effective plasmons, the metal-based particles may contain minute unevenness (roughness) on the surface. In this sense, the metal- good.

In consideration of the uniformity of the intensity of the plasmon resonance in the plane of the metal-based grain aggregate, it is preferable that the size irregularity among the metal-based grains is as small as possible. However, even if the particle diameter is somewhat uneven, it is not preferable that the distance between the large particles is large, and it is preferable that the small particles are embedded between the large particles to facilitate the interaction between the large particles.

In the metal-based grain aggregate [i], the metal-based particles are arranged such that the average distance (distance between the average particles) to the adjacent metal-based particles is in the range of 1 nm to 150 nm. By densely arranging the metal-based particles in this way, remarkably strong plasmon resonance and remarkable elongation of the action range of plasmon resonance can be achieved, and the effect (3) can be further realized. The average particle distance is preferably in the range of 1 nm to 100 nm, more preferably in the range of 1 nm to 50 nm, and still more preferably in the range of 1 nm to 20 nm, in order to effectively obtain the effects (1) to (3) It is mine. If the distance between the average particles is less than 1 nm, electron movement based on the Dexter mechanism occurs between the particles, which is disadvantageous in view of inactivation of the local plasmon.

The average particle-to-particle distance is a distance between particles of the metal-based particle-assembled body in which the metal-based particles are arranged two-dimensionally. Is the mean value of the distance between the particles of these 30 particles. The distance between particles with adjacent particles is a value obtained by measuring the distance between all the adjacent particles (the distance between the surfaces), and averaging them.

The number of the metal-based particles contained in the metal-based grain aggregate [i] is 30 or more, and preferably 50 or more. By forming an aggregate containing 30 or more metal-based particles, extremely strong plasmon resonance and elongation of the action range of plasmon resonance are expressed by interaction between the internally-generated plasmons of the metal-based particles.

When the metal-based grain aggregate [i] is applied to an optical element as an enhancement element, the number of metal-based grains contained in the metal-based grain aggregate [i] is 300 or more, Or more.

The number density of the metal-based particles in the metal-based grain aggregate [i] is preferably 7 / μm ² or more, more preferably 15 / μm ² or more.

(Metal particle aggregate [ii])

The metal-based particle aggregate (metal-based particle aggregate [ii]) having the characteristics of the above-mentioned [ii] is very advantageous in the following respects.

(I) In the absorption spectrum in the visible light region, the maximum wavelength of the plasmon peak on the longest wavelength side exists in a specific wavelength region. Concretely, the metal-based particle aggregate [ii] has a maximum wavelength of the plasmon peak in a range of 30 nm to 500 nm (as compared with the maximum wavelength of the reference metal-based particle aggregate (X) (Blue shift) toward the shorter wavelength side in the range of, e.g., 30 nm to 250 nm. Typically, the maximum wavelength of the plasmon peak is in the range of 350 nm to 550 nm.

The metal-based grain aggregate [ii] capable of having a plasmon peak in the blue or near-wavelength region is very useful for light emission enhancement of a light-emitting element using a light emitting material of blue or near wavelength region, It is possible to increase the luminous efficiency to a sufficient level even when a blue light emitting material having a relatively low luminous efficiency is used. In addition, when applied to a photoelectric conversion element (solar cell element or the like), for example, by blue-shifting the resonance wavelength, it is possible to effectively use the wavelength region that was not available in the active layer itself, and the conversion efficiency can be improved.

The blue shift has a structure in which the metal-based particle aggregate [ii] has a specific number or more of a large number of metal-based particles having a specific shape arranged two-dimensionally apart from each other. Thus, the interaction between metal- Is thought to be due to what is happening.

Here, when comparing the maximum wavelength of the peak on the longest wavelength side between the certain metal-based grain aggregate and the reference metal-based grain aggregate (X) or the absorbance at the maximum wavelength thereof, a microscope ("OPTIPHOT -88 ") and a spectrophotometer (" MCPD-3000 "manufactured by OTSUKA DENKI Co., Ltd.) are used to measure the absorption spectrum by narrowing the measurement visual field.

The reference metal particle aggregate (X) is obtained by dispersing the metal particle (A) having the average particle diameter, the average particle diameter, the height and the same material of the metal particle aggregate as the object of the absorption spectrum measurement, Is in the range of 1 占 퐉 to 2 占 퐉 and has such a size as to be capable of performing absorption spectroscopy using the microscope in a state of being laminated on a glass substrate.

The absorption spectral waveform of the reference metal particle aggregate (X) is determined by the particle diameter and height of the metal-based particle (A), the dielectric function of the material of the metal-based particle (A) , It is also possible to calculate theoretically according to the 3D-FDTD method using the dielectric function of the substrate (e.g., glass substrate).

Further, the metal-based grain aggregate [ii] has a structure in which a specific number or more of relatively large metal-based particles having a specific shape are arranged two-dimensionally apart from each other, and (II) exhibits extremely strong plasmon resonance (The same as the effect (1) of the metal-based grain aggregate [i]) and (III) the range of action of the plasmon resonance (the range of enhancement by plasmons) i] (the same as the effect (2)), and the like. The metal-based particle aggregate [ii] has an absorbance at a maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region of not less than 1, more preferably not less than 1.5, It can be about two more.

The specific constitution of the metal-based particle aggregate [ii] is preferably a specific constitution of the metal-based grain aggregate [i] (the material of the metal-based particle, the average particle diameter, the average height, the aspect ratio, the distance between the average particles, Non-conductivity, etc.) can be made basically the same. The definitions of the mean particle diameter, the average height, the aspect ratio, the distance between the average particles, and the like are also the same as those of the metal particle aggregate [i].

The average particle diameter of the metal-based particles is in the range of 200 nm to 1600 nm, preferably 200 nm to 1200 nm, more preferably 250 nm to 500 nm, in order to effectively obtain the effects (I) to (III) , More preferably in the range of 300 nm to 500 nm. By forming the aggregate in which two or more predetermined number (30 or more) of such large metal-based particles are arranged, it is possible to realize a remarkably strong elongation with a remarkable range of action of plasmon resonance and plasmon resonance. Also, in expressing the characteristic (shift of the plasmon peak to the short wavelength side) of the above-mentioned [ii], the metal-based particles are required to have an average particle diameter of 200 nm or more, and preferably 250 nm or more. The average particle diameter of the metal-based particles is desirably appropriately selected depending on the kind of the optical element to which the metal-based particle aggregate is applied as the enhancing element and the kind of the material constituting the metal-based particle.

In the metal-based particle aggregate [ii], the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region depends on the average particle diameter of the metal-based particles. That is, when the average particle diameter of the metal-based particles exceeds a predetermined value, the maximum wavelength of the plasmon peak shifts to the short wavelength side (blue shift).

The average height of the metal-based particles is in the range of 55 nm to 500 nm and is preferably in the range of 55 nm to 300 nm, more preferably in the range of 70 nm to 150 nm in order to effectively obtain the effects (I) to (III) It is mine. The aspect ratio of the metal-based particles is in the range of 1 to 8, and it is preferable that the aspect ratio is appropriately selected according to the type of the optical element to which the metal-based particle aggregate is applied as the enhancing element within the range.

The metal-based particles in the metal-based particle aggregate [ii] are preferably arranged so that the distance between the average particles is in the range of 1 nm to 150 nm. More preferably 1 nm to 100 nm, further preferably 1 nm to 50 nm, particularly preferably 1 nm to 20 nm. By densely arranging the metal-based particles in this way, the interactions between the local plasmons of the metal-based particles are effectively produced, and the effects (I) to (III) described above are easily exhibited. Since the maximum wavelength of the plasmon peak depends on the distance between the average particles of the metal-based particles, by adjusting the distance between the average particles, the degree of blue shift of the plasmon peak on the longest wavelength side and the maximum wavelength of the plasmon peak are controlled It is possible. If the distance between the average particles is less than 1 nm, electron movement based on the Dexter mechanism occurs between the particles, which is disadvantageous in view of inactivation of the local plasmon.

The number of the metal-based particles contained in the metal-based particle aggregate [ii] is 30 or more, preferably 50 or more. By forming aggregates containing 30 or more metal-based particles, interactions between the internally-generated plasmons of the metal-based particles are effectively produced, and the characteristics of the above-mentioned [ii] and the effects of the above (I) to (III) can be manifested.

When the metal-based particle aggregate [ii] is applied to an optical element as an enhancement element, the number of the metal-based particles contained in the metal-based grain aggregate [ii] is 300 or more, Or more.

The number density of the metal-based particles in the metal-based particle aggregate [ii] is not less than 7 / ㎛ ^2, and more preferably larger than 15 / ㎛ ^2.

(Metal particle aggregate [iii])

The metal-based grain aggregate (metal-based grain aggregate [iii]) having the feature [iii] described above is very advantageous in the following respects.

(A) the absorbance at the maximum wavelength of the peak on the longest wavelength side in the visible light region which is the plasmon peak, can be regarded as an aggregate in which the metal-based particles are simply aggregated without any interaction between particles, Is larger than the aggregate (Y), and thus exhibits extremely strong plasmon resonance. Therefore, when applied to a light emitting device, a stronger luminescent enhancing effect can be obtained as compared with the case of using a conventional plasmon material, Can be dramatically increased. Further, in the case where the present invention is applied to a photoelectric conversion element, the conversion efficiency can be dramatically increased. This strong plasmon resonance is believed to be expressed by the interaction between the metal plasmons and the local plasmons.

As described above, the intensity of the plasmon resonance of the plasmon material can be evaluated sharply from the magnitude of the absorbance at the maximum wavelength of the plasmon peak, but the metal-based particle aggregate [iii] The absorbance at the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region can be 1 or more, more preferably 1.5 or more, or even 2 or so.

As described above, when comparing the maximum wavelength of the peak on the longest wavelength side between the certain metal-based grain aggregate and the reference metal-based grain aggregate (Y) or the absorbance at the maximum wavelength, they are measured with a microscope Quot; OPTIPHOT-88 ") and a spectrophotometer (" MCPD-3000 " manufactured by OTSUKA DENKI CO., LTD.) Are used to narrow the measurement field and perform absorption spectrophotometry.

The reference metal particle aggregate (Y) is obtained by mixing the metal particle (B) having the average particle diameter, the particle diameter, height, and the same material as the average particle diameter and height of the metal particle aggregate to be subjected to the absorption spectrum measurement, Is in the range of 1 탆 to 2 탆, and has a size such that the absorption spectrum measurement using the microscope can be performed in a state of being laminated on a glass substrate.

When comparing the absorbance at the maximum wavelength of the peak on the longest wavelength side between the metal particle aggregate and the reference metal particle aggregate (Y) to be subjected to the absorption spectrum measurement, as described below, Absorbing spectrum of the reference metal grain aggregate (Y) in terms of the maximum absorption wavelength at the maximum wavelength of the peak in the absorption spectrum is to be compared. Specifically, the absorption spectra of the metal-based grain aggregate and the reference metal-based grain aggregate (Y) are respectively obtained, and the absorbance at the maximum wavelength of the peak on the longest wavelength side in each absorption spectrum is measured by the respective coating rates The coating rate of the surface of the substrate by the particles) is calculated and compared.

Further, the metal-based particle aggregate [iii] has a structure in which a specific number or more of relatively large metal-based particles having a specific shape are arranged two-dimensionally apart from each other, and (B) the action range of plasmon resonance (The same effect as the effect (2) of the metal-based grain aggregate [i]), and (C) the maximum wavelength of the plasmon peak can exhibit a peculiar shift (The same as the effect (3) of the metal-based grain aggregate [i]).

The metal-based particle aggregate [iii] (in a state of being laminated on a glass substrate) has a maximum absorption spectrum in the absorption spectrum in the visible light region measured according to the absorption spectrophotometry, depending on the shape of the metal- The plasmon peak can exhibit a maximum wavelength in a wavelength range of 350 nm to 550 nm, for example. In addition, the metal-based grain aggregate [iii] has a grain size of about 30 nm to 500 nm (for example, about 30 nm to about 250 nm), which is typically about 30 nm to about 500 nm in comparison with the case where the metal- Blue shift can be generated.

The specific constitution of the metal-based grain aggregate [iii] is not particularly limited as long as the specific constitution of the metal-based grain aggregate [i] (the material of the metal-based grain, the average particle diameter, the average height, the aspect ratio, the distance between the average particles, Non-conductivity, etc.) can be made basically the same. The definitions of the mean particle diameter, the average height, the aspect ratio, the distance between the average particles, and the like are also the same as those of the metal particle aggregate [i].

The average particle diameter of the metal-based particles is in the range of 200 nm to 1600 nm, and the feature [iii] (the absorbance at the maximum wavelength of the plasmon peak on the longest wavelength side is higher than that of the reference metal- In order to effectively obtain the effects of the above (A) to (C), it is preferable to set the range of 200 nm to 1200 nm, more preferably 250 nm to 500 nm, further preferably 300 nm to 500 nm It is mine. As described above, it is critical to form relatively large metal-based particles, and by forming an aggregate in which two or more predetermined number (30 or more) of large metal-based particles are arranged, remarkably strong plasmon resonance, And the shift of the plasmon peak to the short wavelength side can be realized. The average particle diameter of the metal-based particles is desirably appropriately selected depending on the kind of the optical element to which the metal-based particle aggregate is applied as the enhancing element and the kind of the material constituting the metal-based particle.

The average height of the metal-based particles is in the range of 55 nm to 500 nm and is preferably 55 nm to 300 nm, more preferably 55 nm to 300 nm in order to effectively obtain the characteristics of the above [iii] and the effects of the above (A) Is in the range of 70 nm to 150 nm. The aspect ratio of the metal-based particles is in the range of 1 to 8, and it is preferable that the aspect ratio is appropriately selected according to the type of the optical element to which the metal-based particle aggregate is applied as the enhancing element within the range.

Since the characteristics of [iii] are effectively obtained, it is preferable that the metal-based particles constituting the metal-based particle aggregate [iii] are as uniform as possible in terms of their size and shape (average particle diameter, average height and aspect ratio) . That is, by making the size and shape of the metal-based particles uniform, the plasmon peak becomes sharp, and accordingly, the absorbance of the plasmon peak on the longest wavelength side becomes higher than that of the reference metal-based particle aggregate (Y). The reduction in unevenness in the size and shape between the metal-based particles is advantageous from the viewpoint of uniformity of the intensity of plasmon resonance in the surface of the metal-based particle aggregate. However, as described above, it is not preferable that the distance between the large particles is large even if the particle diameter is somewhat uneven, and it is preferable to facilitate the interaction between the large particles by embedding small particles therebetween .

The metal-based particles in the metal-based particle aggregate [iii] are preferably arranged so that the distance between the average particles is in the range of 1 nm to 150 nm. More preferably 1 nm to 100 nm, further preferably 1 nm to 50 nm, particularly preferably 1 nm to 20 nm. By densely arranging the metal-based particles in this way, the interaction between the internally-generated plasmons of the metal-based particles is effectively generated, and the characteristics of the above-mentioned [iii] and further the effects of the above-mentioned (A) to (C) can be effectively exhibited. If the distance between the average particles is less than 1 nm, electron movement based on the Dexter mechanism occurs between the particles, which is disadvantageous in view of inactivation of the local plasmon.

The number of the metal-based particles contained in the metal-based particle aggregate [iii] is 30 or more, preferably 50 or more. By forming aggregates containing 30 or more metal-based particles, the interactions between the internally-generated plasmons of the metal-based particles are effectively produced, and the characteristics of the [iii] and the effects of the above (A) to (C) can be effectively exhibited .

When the metal-based grain aggregate [iii] is applied to an optical element as an enhancement element, the number of metal-based grains contained in the metal-based grain aggregate [iii] is 300 or more, more preferably 17500 Or more.

The number density of the metal-based particles in the metal-based particle aggregate [iii] is not less than 7 / ㎛ ^2, and more preferably larger than ^15/2 ㎛.

As described above, the metal-based grain aggregate [iii] can be obtained by controlling the metal species, the size, the shape, the average distance between the metal-based particles, and the like of the metal-based particles constituting the metal-based grain-based aggregate [iii].

The metal-based grain aggregate obtained according to the production method of the present invention has at least any one of the above-mentioned features [i] to [iii], and more typically any two or more of the features [i] to [iii] More typically, all the features of [i] to [iii].

In the present invention, an insulating layer for covering the surface of each metal-based particle may be formed on the thin film of the metal-based particle aggregate by providing an insulating layer forming step after the above-described particle growth step. Such an insulating layer is preferable not only for securing the non-conductivity (non-conductivity between metal particles) of the metal-based particle aggregate thin film, but also for applying the metal-based particle aggregate to an optical element. That is, in an optical element such as a light-emitting element driven by an electric energy or a photoelectric conversion element, a current flows in each layer constituting it, but if an electric current flows in the thin film of the metal-based particle aggregate, an enhancement effect due to plasmon resonance is not sufficiently obtained There is a concern. It is possible to provide electrical insulation between the metal particle aggregate thin film and the constituent layers of the optical element adjacent to the metal particle aggregate thin film even when applied to an optical element by providing the insulating layer capping the metal particle aggregate thin film, It is possible to prevent an electric current from being injected into the metal-based particles constituting the electrode.

The material constituting the insulating layer is not particularly limited as long as it has good insulating properties. For example, SiO ₂ , Si ₃ N ₄ and the like can be used in addition to spin-on glass (SOG) containing an organosiloxane material. The thickness of the insulating layer is not particularly limited as long as the desired insulating property can be ensured. However, as will be described later, the distance between the active layer (for example, the light absorbing layer of the light emitting element or the light absorbing layer of the photoelectric conversion element) The closer the thickness is, the better the insulating property is.

The metal-based grain aggregate obtained according to the production method of the present invention is very useful as an enhancing element for optical elements such as a light-emitting element, a photoelectric conversion element (solar cell element, etc.). By applying the metal-based grain aggregate according to the present invention to an optical element, the luminous efficiency and conversion efficiency of the optical element can be remarkably improved. The metal-based grain aggregate can be incorporated in various optical elements in a state integrated with the substrate used for the production thereof.

As described above, since the metal-based grain aggregate obtained according to the production method of the present invention exhibits extremely strong plasmon resonance and further remarkably elongates the action range of plasmon resonance (the range of enhancement by plasmon) , The active layer (the light absorbing layer in the light emitting layer or the photoelectric conversion element in the light emitting element) having a thickness of not less than 10 nm and not less than 20 nm and having a thickness not less than that of the active layer. Further, the active layer disposed at a position of 10 nm, for example, several tens nm (for example, 20 nm), more than several hundred nm or more) can also be very effectively enhanced.

In addition, the enhancing effect by the plasmon tends to decrease as the distance between the active layer and the metal-based particle aggregate becomes larger, so that the smaller the distance is, the better. The distance between the active layer and the metal-based grain aggregate is preferably 100 nm or less, more preferably 20 nm or less, and further preferably 10 nm or less.

It is preferable that the maximum wavelength of an emission wavelength (for example, in the case of a light emitting element) or an absorption wavelength (in the case of a photoelectric conversion element, for example) represented by the active layer matches or is close to the maximum wavelength of the plasmon peak of the metal-based grain aggregate. Thus, the enhancing effect due to the plasmon resonance can be enhanced more effectively. The maximum wavelength of the plasmon peak of the metal-based particle aggregate can be controlled by adjusting the metal species, the average particle diameter, the average height, the aspect ratio, and / or the distance between the average particles of the metal particles constituting the peak.

The light emitting layer may be formed, for example, of 1) a monomolecular film in which dye molecules are arranged in a planar shape, 2) a dye doped in a matrix, 3) a low molecular weight luminescent material, 4) have.

1) can be obtained by spin coating the dye-containing liquid and then removing the solvent. Specific examples of dye molecules are sold by Exciton under the names Rhodamine 101, Rhodamine 110, Rhodamine 560, Rhodamine 6G, Rhodamine B, Rhodamine 640 and Rhodamine 700, which are marketed by Exciton. And a coumarin-based coloring matter such as coumarin 503 which has been used.

2) can be obtained by a method of spin-coating a liquid containing dye molecules and a matrix material, and then removing the solvent. As the matrix material, a transparent polymer such as polyvinyl alcohol or polymethyl methacrylate can be used. Specific examples of the dye molecule may be the same as the light emitting layer of 1).

3) can be obtained by a dry or wet film formation method including a spin coating method and a vapor deposition method. Specific examples of the luminescent low molecule include tris (8-quinolinolato) aluminum complex [tris (8-hydroxyquinoline) aluminum complex; Alq ³ ], bis (benzoquinolinolato) beryllium complex [BeBq], and the like.

4) can be obtained by a wet film-forming method using a luminescent polymer-containing liquid such as a spin coating method. Specific examples of the luminescent polymer include π conjugated polymers such as F8BT [poly (9,9-dioctylfluorene-alt-benzothiadiazole)], poly (p-phenylenevinylene) .

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Production of metal particle aggregate]

≪ Example 1 >

Silver particles were very slowly grown on a soda glass substrate using a DC magnetron sputtering apparatus under the following conditions to form a thin film of a metal-based grain aggregate on the entire surface of the substrate to obtain a metal-based grain-particle aggregate thin film laminated substrate .

Use gas: argon,

Chamber pressure (sputter gas pressure): 10 Pa,

Distance between substrate and target: 100 mm,

Sputter power: 4 W,

Average particle diameter growth rate (average particle diameter / sputter time): 0.9 nm / min,

Average height growth rate (= average deposition rate = average height / sputter time): 0.25 nm / min,

Substrate temperature: 300 DEG C,

Substrate size and shape: Square with 5 cm on each side.

Fig. 1 is an SEM image of the obtained metal-based particle aggregate thin film viewed from directly above. Fig. 1 (a) is an enlarged image of 10000 times scale, and Fig. 1 (b) is an enlarged image of 50000 times scale. 2 is an AFM image showing the obtained thin film of the metal-based particle aggregate. &Quot; VN-8010 " manufactured by Keyence Corporation was used for AFM image-taking (the same applies hereinafter). The size of the image shown in Fig. 2 is 5 占 퐉 占 5 占 퐉.

From the SEM image shown in Fig. 1, the average particle diameter based on the above definition of the silver particles constituting the metal-based particle aggregate of this example was found to be 335 nm and the average particle distance was found to be 16.7 nm. From the AFM image shown in Fig. 2, the average height was found to be 96.2 nm. From these, the aspect ratio (average particle diameter / average height) of the silver particles was calculated to be 3.48, and it was found from the obtained image that the silver particles had a flat shape. In addition, from the SEM image, the present embodiment is a metal-based particle aggregate, from about 6.25 × ¹⁰ 10 pieces (about 25 / ㎛ ²⁾ has been found that a particle.

In addition, it was confirmed that when the tester ("E2378A" manufactured by Hewlett-Packard Co., Ltd.) was connected to the surface of the metal-based particle aggregate thin film to check the conductivity, it was confirmed that it did not have conductivity.

≪ Comparative Example 1 &

Sputtering was carried out in the same manner as in Example 1 except that the average height growth rate (deposition rate) was set to 60.6 nm / min and the treatment time (deposition time) was set to 2 minutes to form a silver thin film. 3 is an AFM image showing the obtained silver film. The size of the image shown in Fig. 3 is 5 占 퐉 占 5 占 퐉.

The average height growth rate in this comparative example is a value obtained by dividing the average height of the silver layer formed on the substrate by the sputter time. The average height of the silver layer was measured by setting the peeling line on the silver layer at the end of the tweezers and calculating the difference in height between the outer surface of the silver layer and the silver layer side surface of the substrate at random, As an average value.

From the AFM image shown in Fig. 3, the average height was found to be 121.3 nm. When the conductivity of the silver foil film was confirmed by using the same tester as described above, it was confirmed that it had conductivity. That is, the amount of silver supported on the substrate in this comparative example was substantially the same as in Example 1, but it was confirmed that the individual silver particles were not separated from each other and formed a continuous film.

[Absorption spectrum measurement of silver foil film]

4 is an absorption spectrum measured according to the absorption spectrophotometry of the thin film of the metal-based grain aggregate obtained in Example 1 and the silver-plated film obtained in Comparative Example 1 (both of which are laminated on the substrate). (See, for example, K. Lance Kelly, et al., &Quot; The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Enviroment ", The Journal of Physical Chemistry B, 2003, 107, 668) As described above, it is common that the flat silver particles as in Example 1 have a plasmon peak in the vicinity of 550 nm when the average particle diameter is 200 nm and in the vicinity of 650 nm when the average particle diameter is 300 nm (All are particles alone).

On the other hand, the metal-based particle aggregate thin film of Example 1 has an average particle diameter of about 300 nm (335 nm) of silver particles constituting the metal-based particle aggregate thin film, It can be seen that the maximum wavelength of the plasmon peak is about 450 nm and shifted toward the short wavelength side. This phenomenon can be manifested when the silver particles are large particles having the predetermined shape and are arranged very closely at the distance between the average particles as in the first embodiment.

Further, it can be seen that the absorbance at the maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region is about 1.9, indicating extremely strong plasmon resonance. On the other hand, since the silver foil film of Comparative Example 1 was a continuous film, it did not show a plasmon peak based on plasmon resonance.

The absorption spectrum shown in Fig. 4 is a spectrum obtained by irradiating incident light in the ultraviolet to visible region from the direction perpendicular to the substrate surface on the back side (opposite side of the silver foil film) of the glass substrate on which the silver foil films are stacked, The intensity I of the transmitted light in one entire direction and the same thickness of the substrate as the substrate are irradiated with the same incident light as before from a direction perpendicular to the surface of the substrate on which the silver foil film is not stacked, And the intensity (I ₀ ) of the transmitted light in the entire direction transmitted from the opposite side are measured by using an integrating sphere spectrophotometer. The absorbance on the vertical axis is represented by the following formula:

Absorbance = -log ₁₀ (I / I ₀ )

Respectively.

[Preparation of Reference Metal-Based Particle Assembly and Measurement of Absorption Spectrum]

According to the method shown in Fig. 5, a substrate laminated with reference metal grain aggregates was produced. First, a resist (ZEP520A, manufactured by Nippon Zeon Co., Ltd.) was spin-coated on substantially the entire surface of a soda glass substrate 100 having a length of 5 cm and a width of 5 cm (Fig. 5 (a)). The thickness of the resist 400 was about 120 nm. Next, a circular opening 401 is formed in the resist 400 by electron beam lithography (FIG. 5 (b)). The diameter of the circular opening 401 was about 350 nm. The distance between the centers of the adjacent circular openings 401 was about 1500 nm.

Then, the silver film 201 was deposited on the resist 400 having the circular opening 401 by a vacuum evaporation method (FIG. 5 (c)). The thickness of the silver film 201 was set to about 100 nm. Finally, the substrate having the silver film 201 is immersed in NMP (N-methyl-2-pyrrolidone manufactured by Tokyo Chemical Industry Co., Ltd.) and left at room temperature for 1 minute in the ultrasonic device, The silver film 201 formed on the soda glass substrate 100 was peeled off so that only the silver film 201 (silver particles) in the circular opening 401 remained on the soda glass substrate 100 to obtain a laminate substrate of reference metal- 5 (d)).

Fig. 6 is an SEM image of the reference metal-based particle aggregate thin film obtained in the obtained reference metal-based particle aggregate thin film laminated substrate viewed directly above. FIG. 6A is an enlarged image of 20000 times scale, and FIG. 6B is an enlarged image of 50000 times scale. From the SEM image shown in Fig. 6, the average particle diameter based on the above definition of the silver particles constituting the reference metal-based particle aggregate thin film was found to be 333 nm and the average particle distance was found to be 1264 nm. From the AFM images obtained separately, the average height was found to be 105.9 nm. From the SEM image, it was found that the reference metal-based particle aggregate had about 62500 silver particles.

The absorption spectra of the metal-based grain-particle assembly thin-film laminated substrate of Example 1 were measured according to the measurement method using the objective lens (100 times) of the above-mentioned microscope. 7, the substrate 501 side (opposite to the metal-based particle aggregate thin film 502) of the metal-based grain-particle-aggregate thin film-laminated substrate 500 has a structure in which an incident light Respectively. The transmitted light that has passed through the metal particle aggregate thin film 502 and reaches the objective lens 600 of 100 times is collected by the objective lens 600. The collected light is detected by the spectrophotometer 700, The spectrum was obtained.

An ultraviolet visible spectrophotometer " MCPD-3000 " manufactured by Otsuka Electronics Co., Ltd. was used for the spectrophotometer 700, and a BD Plan 100 / 0.80 ELWD manufactured by Nikon Co., Ltd. was used for the objective lens 600. [ The results are shown in Fig. The maximum wavelength of the plasmon peak on the longest wavelength side in the visible light region was about 450 nm as in the absorption spectrum in Fig. On the other hand, the absorption spectrum of the reference metal-based grain-particle aggregate thin film laminate substrate was measured by a measurement method using an objective lens of a microscope, and the maximum wavelength of the peak on the longest wavelength side in the visible light region was 654 nm. The metal-based grain-aggregated thin-film laminated substrate of Example 1 has a blue-shifted peak wavelength of the peak at the longest wavelength side in the visible light region by about 200 nm, as compared with the reference metal-based grain-

The metal-based grain-aggregated thin film laminated substrate of Example 1 had an absorbance at the maximum wavelength of the peak at the longest wavelength side in the visible light region of 1.744 (FIG. 8) and 0.033 of the reference metal-based grain aggregated thin film laminated substrate. In order to compare the absorbance at the maximum wavelength of the peak on the longest wavelength side between the metal-based grain-particle-aggregate thin film laminated substrate and the reference metal-grain-layered thin-film laminated substrate of Example 1 in comparison with the same number of metal- The absorbance obtained from the absorption spectrum was divided by the coating rate of the surface of the substrate with the metal-based particles, which is a parameter corresponding to the number of metal-based particles, and the absorbance / coverage was calculated. The absorbance / coverage of the metal-based particle-aggregate thin film laminated substrate of Example 1 was 2.04 (coverage rate: 85.3%), and the absorbance / coverage of the reference metal-based particle assembly thin film laminate substrate was 0.84 (coverage ratio: 3.9%).

[Preparation of organic EL device and evaluation of luminescence intensity]

≪ Example 2 >

The metal-based particle aggregate thin film described in Example 1 was formed on a 0.5 mm thick soda glass substrate by growing silver particles under the same conditions as in Example 1. [ Immediately thereafter, a spin-on-glass (SOG) solution was spin-coated on the thin film of the metal-based particle aggregate to laminate an insulating layer having an average thickness of 80 nm. As the SOG solution, an organic SOG material "OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo K.K., diluted with ethanol, was used.

Next, an IZO layer (thickness of 22 nm) serving as an anode electrode was laminated on the insulating layer as an anode electrode by ion sputtering method, and then the solution for forming a hole injection layer was spin-coated on the anode electrode to inject holes of 20 nm in average thickness Layer. As the solution for forming the hole injection layer, a product "Plexcore AQ 1200" manufactured by PLEXTRONICS, which was diluted with ethanol to a predetermined concentration, was used. The total average thickness of the insulating layer, the anode and the hole injection layer (i.e., the average distance from the surface of the metal-based particle-collecting thin film to the light-emitting layer) is 122 nm.

Subsequently, a polymer light-emitting material soluble in an organic solvent was dissolved in an organic solvent at a predetermined concentration and spin-coated on the hole injection layer to form a light-emitting layer having a thickness of 100 nm. Thereafter, a NaF layer (2 nm thick) serving as an electron injecting layer, a Mg layer (2 nm thick) serving as a cathode, and an Ag layer (10 nm thick) serving as an electron injecting layer were laminated on the light emitting layer in this order. The resulting device was sealed from the surface side using an encapsulant ("XNR5516ZLV" manufactured by Nagase Kamec Co., Ltd.) to obtain an organic EL device.

≪ Comparative Example 2 &

An organic EL device was fabricated in the same manner as in Example 2 except that the metal-based particle aggregate thin film was not formed.

A constant voltage of 15 V was applied to the organic EL device of Example 2 by a source meter (SourceMeter 2602A, manufactured by Keithley Instruments, Inc.), and the current flowing between the electrodes was 2.3 mA to cause the device to emit light. The luminescence spectrum was measured using a spectrophotometer "CS-2000" manufactured by Konica Minolta, and the obtained luminescence spectrum was integrated into a visible light wavelength region to determine the luminescence intensity. The applied voltage was 15 V in the same manner as in the organic EL device of Example 2 except that the current flowing between the electrodes was 2.7 mA. The organic EL device of Comparative Example 2 The light emission intensity was also determined. As a result, it was confirmed that the organic EL device of Example 2 exhibited about 3.8 times the luminescence intensity as compared with the organic EL device of Comparative Example 2. [

≪ Example 3 >

The metal-based particle aggregate thin film described in Example 1 was formed on a 0.5 mm thick soda glass substrate by growing silver particles under the same conditions as in Example 1. [ Immediately thereafter, a spin-on glass (SOG) solution was spin-coated on the thin film of the metal-based particle aggregate to laminate an insulating layer having an average thickness of 30 nm. As the SOG solution, an organic SOG material "OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo K.K., diluted with ethanol, was used.

Next, an IZO layer (thickness of 22 nm) serving as an anode electrode was laminated on the insulating layer as an anode electrode by ion sputtering method, and then the solution for forming a hole injection layer was spin-coated on the anode electrode to inject holes of 20 nm in average thickness Layer. As the solution for forming the hole injection layer, a product "Plexcore AQ 1200" manufactured by PLEXTRONICS, which was diluted with ethanol to a predetermined concentration, was used. The total average thickness of the insulating layer, the anode electrode, and the hole injection layer (that is, the average distance from the surface of the metal-based particle-aggregate thin film to the light-emitting layer) is 72 nm.

Subsequently, Alq ₃ was formed as a light emitting layer on the hole injection layer to a thickness of 80 nm by a vacuum deposition method. Thereafter, a NaF layer (2 nm thick) serving as an electron injecting layer, a Mg layer (2 nm thick) serving as a cathode, and an Ag layer (10 nm thick) serving as an electron injecting layer were laminated on the light emitting layer in this order. The resulting device was sealed from the surface side using an encapsulant ("XNR5516ZLV" manufactured by Nagase Kamec Co., Ltd.) to obtain an organic EL device.

≪ Comparative Example 3 &

An organic EL device was fabricated in the same manner as in Example 3 except that the metal-based particle aggregate thin film was not formed.

A constant voltage of 11 V was applied to the organic EL device of Example 3 by a source meter (Source meter 2602A type, manufactured by Keithley Instruments, Inc.), and the current flowing between the electrodes was 0.7 mA to cause the device to emit light. The luminescence spectrum was measured using a spectrophotometer "CS-2000" manufactured by Konica Minolta, and the obtained luminescence spectrum was integrated into a visible light wavelength region to determine the luminescence intensity. The applied voltage was 11 V in the same manner as in the organic EL device of Example 3 except that the current flowing between the electrodes was adjusted to 1.1 mA. The organic EL device of Comparative Example 3 The light emission intensity was also determined. As a result, it was confirmed that the organic EL device of Example 3 exhibited an emission intensity about 2.6 times as high as that of the organic EL device of Comparative Example 3.

[Production of photoexcitation light emitting device and evaluation of luminescent enhancement]

≪ Example 4-1 >

The same metal grain aggregate thin film as in Example 1 was formed on a 0.5 mm thick soda glass substrate by growing silver particles under almost the same conditions as in Example 1. [ This metal-based particle aggregate thin film had the same particle shape and a distance between average particles as in Example 1 except that the average height of the metal-based particles was 66.1 nm.

Next, a solution for a coumarin-based light emitting layer was spin-coated on a thin film of the metal-based particle aggregate at 3000 rpm to form an ultra-thin (monomolecular scale) coumarin-based light emitting layer to obtain a light emitting device. The coumarin-based light emitting layer solution was prepared as follows. First, coumarin dye (Exciton Coumarin 503) was dissolved in ethanol to prepare a 5 mM coumarin solution. Separately, an organic spin-on glass (SOG) material ("OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo Co., Ltd.) was diluted with ethanol to 33 vol%. This 33 vol% organic-based SOG material diluent, 5 mM coumarin solution, and ethanol were mixed at a volume ratio of 1: 5: 5 to obtain a coumarin-based light emitting layer solution.

≪ Example 4-2 >

The silver-based particle aggregate thin film described in Example 4-1 was formed on a 0.5 mm thick soda glass substrate by growing silver particles under the same conditions as in Example 4-1. Immediately thereafter, the SOG solution was spin-coated on the metal-based grain aggregate thin film to laminate an insulating layer having an average thickness of 10 nm. As the SOG solution, an organic SOG material "OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo K.K., diluted with ethanol, was used. The "average thickness" means an average thickness when formed on a thin film of metal-based particle aggregates having surface irregularities and was measured as the thickness when the SOG solution was directly spin-coated on a soda glass substrate , The same applies to the comparative example). When the average thickness is relatively small, an insulating layer is formed only in the valley portion of the metal-based particle-aggregate thin film, so that the entire outermost surface of the metal-based particle-collecting thin film can not be covered.

Next, on the outermost surface of the metal-based particle aggregate thin film having the insulating layer, the same solution for the coumarin-based light emitting layer as used in Example 4-1 was spin-coated at 3000 rpm to form an ultra-thin (monomolecular scale) coumarin- To obtain a light emitting device.

<Example 4-3>

A light emitting device was obtained in the same manner as in Example 4-2 except that the insulating layer had an average thickness of 30 nm.

<Example 4-4>

A light emitting device was obtained in the same manner as in Example 4-2 except that the insulating layer had an average thickness of 80 nm.

<Example 4-5>

A light emitting device was obtained in the same manner as in Example 4-2 except that the insulating layer had an average thickness of 150 nm.

<Example 4-6>

A light emitting device was obtained in the same manner as in Example 4-2 except that the insulating layer had an average thickness of 350 nm.

&Lt; Comparative Example 4-1 >

The silver nanoparticle water dispersion (manufactured by Mitsubishi Chemical Co., Ltd., concentration of silver nanoparticles: 25% by weight) was diluted with pure water to a concentration of silver nanoparticles of 6% by weight. Subsequently, 1% by volume of a surfactant was added to the aqueous dispersion of the silver nanoparticles and the mixture was stirred well. Then, 80 vol% of acetone was added to the water dispersion of the obtained silver nanoparticles and sufficiently mixed at room temperature to prepare a silver nanoparticle coating solution.

Next, the above-described silver nanoparticle coating solution was spin-coated on a 1-mm-thick soda glass substrate whose surface was wiped with acetone by spin coating at 1500 rpm, and then left as it is in the air for 1 minute. To obtain a metal particle-aggregated thin film laminated substrate.

9 is an SEM image of the metal-based particle aggregate thin film on the metal-based particle aggregate thin film laminated substrate obtained in Comparative Example 4-1, viewed from directly above, and is an enlarged image at a magnification of 10,000 times. 10 is an AFM image showing the metal-based particle aggregate thin film in the metal-based particle-aggregate thin film laminated substrate obtained in Comparative Example 4-1. The size of the image shown in Fig. 10 is 5 占 퐉 占 5 占 퐉.

From the SEM image shown in Fig. 9, the average particle diameter based on the above definition of the silver particles constituting the metal-based particle aggregate thin film of Comparative Example 4-1 was found to be 278 nm and the average particle distance was found to be 195.5 nm. From the AFM image shown in Fig. 10, the average height was found to be 99.5 nm. From these, the aspect ratio (average particle diameter / average height) of the silver particles was calculated to be 2.79, and it was also found from the obtained image that the silver particles had a flat shape. From the SEM image, it can be seen that the metal-based particle aggregate of Comparative Example 4-1 has silver particles of about 2.18 × 10 ¹⁰ (about 8.72 / μm ² ).

11 shows the absorption spectra of the metal-based grain-particle-aggregated thin-film laminated substrate obtained in Example 4-1 and Comparative Example 4-1, according to the measurement method using the above-described integral-section spectrophotometer. Fig. 12 shows an absorption spectrum according to a measurement method using an objective lens (100 times) of a microscope of the thin film laminate substrate of the metal-based particle assembly obtained in this Comparative Example 4-1. In any of the measurement methods, in the metal-based grain-particle composite thin film laminated substrate obtained in Comparative Example 4-1, the peak wavelength of the peak on the longest wavelength side in the visible light region was 611 nm. This maximum wavelength is almost the same as the maximum wavelength of the reference metal particle aggregate thin film laminate substrate corresponding to the metal particle aggregate thin film laminate substrate of this Comparative Example 4-1 and the metal particle aggregate thin film of this Comparative Example 4-1 is almost blue Does not indicate a shift. 11, the peak wavelength of the absorption spectrum of Example 4-1 (the maximum wavelength of the plasmon peak on the longest wavelength side) is larger than the peak wavelength of the absorption spectrum of Comparative Example 4-1, Also, it can be seen that the plasmon peak on the longest wavelength side is sharpened, and the absorbance at the maximum wavelength is high.

The absorbance at the maximum wavelength of the peak at the longest wavelength side in the visible light region obtained from the light absorption spectrum in Fig. 12 is 0.444, and the coverage rate of the substrate surface with the metal-based particles is 53.2%, so that the absorbance / coverage ratio is 0.83 . This absorbance / coating ratio is smaller than that of the reference metal-based particle-aggregate thin film laminated substrate.

Then, in the same manner as in Example 4-1, a coumarin-based light emitting layer was formed on the metal-based particle aggregate thin film to obtain a light emitting device.

&Lt; Comparative Example 4-2 &

A thin film of the metal-based particle aggregate described in Comparative Example 4-1 was formed on a 1-mm-thick soda glass substrate in the same manner as in Comparative Example 4-1. Immediately thereafter, the SOG solution was spin-coated on the metal-based particle aggregate thin film to laminate an insulating layer having an average thickness of 10 nm. As the SOG solution, an organic SOG material "OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo K.K., diluted with ethanol, was used.

Then, in the same manner as in Example 4-2, a coumarin-based light emitting layer was formed on the outermost surface of the metal-based particle aggregate thin film having the insulating layer to obtain a light emitting device.

&Lt; Comparative Example 4-3 &

A light emitting device was obtained in the same manner as in Comparative Example 4-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Comparative Example 4-4 &

A light emitting device was obtained in the same manner as in Comparative Example 4-2 except that the insulating layer had an average thickness of 80 nm.

&Lt; Comparative Example 4-5 &

A light emitting device was obtained in the same manner as in Comparative Example 4-2 except that the insulating layer had an average thickness of 150 nm.

&Lt; Comparative Example 4-6 >

A light emitting device was obtained in the same manner as in Comparative Example 4-2 except that the average thickness of the insulating layer was 350 nm.

&Lt; Comparative Example 5 &

A light emitting device was obtained in the same manner as in Example 4-1 except that the metal-based particle aggregate thin film was not formed.

&Lt; Example 5-1 >

A thin film of the metal-based particle aggregate described in Example 4-1 was formed on a 0.5 mm thick soda glass substrate in the same manner as in Example 4-1.

Next, a solution for the Alq ₃ light emitting layer was spin-coated on the metal-based particle aggregate thin film to form an Alq ₃ light emitting layer having an average thickness of 30 nm. The solution for the Alq ₃ light emitting layer was prepared by dissolving Alq ₃ (Tris- (8-hydroxyquinoline) aluminum) in chloroform so that the concentration was 0.5% by weight.

&Lt; Example 5-2 >

A thin film of a metal-based particle aggregate having an insulating layer with an average thickness of 10 nm was formed in the same manner as in Example 4-2, and then an Alq ₃ light emitting layer having an average thickness of 30 nm was formed in the same manner as in Example 5-1, Device was obtained.

&Lt; Example 5-3 >

A light emitting device was obtained in the same manner as in Example 5-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Example 5-4 >

A light emitting device was obtained in the same manner as in Example 5-2 except that the insulating layer had an average thickness of 80 nm.

<Example 5-5>

A light emitting device was obtained in the same manner as in Example 5-2 except that the insulating layer had an average thickness of 150 nm.

&Lt; Comparative Example 6-1 >

After the thin film of the metal-based particle aggregate described in Comparative Example 4-1 was formed on a 1-mm-thick soda glass substrate in the same manner as in Comparative Example 4-1, an Alq 3 film having an average thickness of 30 nm ₃ light emitting layer was formed to obtain a light emitting element.

&Lt; Comparative Example 6-2 &

A thin film of a metal-based particle aggregate having an insulating layer with an average thickness of 10 nm was formed in the same manner as in Comparative Example 4-2, and then an Alq ₃ light emitting layer having an average thickness of 30 nm was formed in the same manner as in Example 5-1, Device was obtained.

&Lt; Comparative Example 6-3 &

A light emitting device was obtained in the same manner as in Comparative Example 6-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Comparative Example 6-4 &

A light emitting device was obtained in the same manner as in Comparative Example 6-2 except that the average thickness of the insulating layer was 80 nm.

&Lt; Comparative Example 6-5 >

A light emitting device was obtained in the same manner as in Comparative Example 6-2 except that the insulating layer had an average thickness of 150 nm.

&Lt; Comparative Example 7 &

A light emitting device was obtained in the same manner as in Example 5-1 except that the metal-based particle aggregate thin film was not formed.

&Lt; Example 6-1 >

A thin film of the metal-based particle aggregate described in Example 4-1 was formed on a 0.5 mm thick soda glass substrate in the same manner as in Example 4-1.

Next, the F8BT luminescent layer solution was spin-coated on the metal-based particle aggregate thin film, and then fired at 170 DEG C for 30 minutes on a hot plate to form an F8BT luminescent layer having an average thickness of 30 nm. The solution for the F8BT light emitting layer was prepared by dissolving F8BT (Luminescence Technology) in chlorobenzene so that the concentration was 1 wt%.

&Lt; Example 6-2 >

A metal-based particle aggregate thin film having an insulating layer with an average thickness of 10 nm was formed in the same manner as in Example 4-2, and then an F8BT light emitting layer having an average thickness of 30 nm was formed in the same manner as in Example 6-1, .

&Lt; Example 6-3 >

A light emitting device was obtained in the same manner as in Example 6-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Comparative Example 8-1 >

After the thin film of the metal-based particle aggregate described in Comparative Example 4-1 was formed on a 1-mm-thick soda glass substrate in the same manner as in Comparative Example 4-1, F8BT having an average thickness of 30 nm A light emitting layer was formed to obtain a light emitting element.

&Lt; Comparative Example 8-2 >

A metal-based particle assembly thin film multilayer substrate having an insulating layer with an average thickness of 10 nm was formed in the same manner as in Comparative Example 4-2, and then an F8BT emission layer having an average thickness of 30 nm was formed in the same manner as in Example 6-1, A light emitting element was obtained.

&Lt; Comparative Example 8-3 >

A light emitting device was obtained in the same manner as in Comparative Example 8-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Comparative Example 9 &

A light emitting device was obtained in the same manner as in Example 6-1 except that the metal-based particle aggregate thin film was not formed.

&Lt; Comparative Example 10-1 >

On the soda glass substrate having a thickness of 1 mm, a conductive silver thin film having a thickness of 13 nm was formed by a vacuum evaporation method. The pressure in the chamber at the time of film formation was 3 x 10 &lt; ^-3 &gt; Subsequently, the substrate on which the conductive silver thin film was formed was fired in an electric furnace at 400 DEG C for 10 minutes to obtain a metal-based particle aggregate thin film laminated substrate.

13 is an SEM image of the metal-based particle-aggregate thin film on the obtained metal-based particle-aggregate thin film-laminated substrate viewed from directly above. FIG. 13A is an enlarged image of 10000 times scale, and FIG. 13B is an enlarged image of 50000 times scale. 14 is an AFM image showing a metal-based particle aggregate thin film in the metal-based particle-aggregate thin film laminated substrate obtained in Comparative Example 10-1. The size of the image shown in Fig. 14 is 5 占 퐉 占 5 占 퐉.

From the SEM image shown in Fig. 13, the average particle diameter based on the above definition of silver particles constituting the metal-based particle aggregate of Comparative Example 10-1 was found to be 95 nm and the average particle distance was found to be 35.2 nm. Also, from the AFM image shown in Fig. 14, the average height was found to be 29.6 nm. From these, the aspect ratio (average particle diameter / average height) of the silver particles is calculated to be 3.20.

15 shows the absorption spectrum of the metal-based grain-particle assembly thin-film laminated substrate obtained in this Comparative Example 10-1 (the measurement method of the absorption spectrum is as described above). The peak wavelength (maximum wavelength of the plasmon peak on the longest wavelength side) of the absorption spectrum of Comparative Example 10-1 is on the longer wavelength side as compared with the peak wavelength of the absorption spectrum of Example 4-1 shown in Fig. 11, , And the absorbance at the peak wavelength is also low.

Next, an Alq ₃ light emitting layer having an average thickness of 30 nm was formed in the same manner as in Example 5-1, thereby obtaining a light emitting device.

&Lt; Comparative Example 10-2 &

A thin film of the metal-based grain aggregate described in Comparative Example 10-1 was formed on a 1-mm-thick soda glass substrate in the same manner as in Comparative Example 10-1. Immediately thereafter, the SOG solution was spin-coated on the metal-based particle aggregate thin film to laminate an insulating layer having an average thickness of 10 nm. As the SOG solution, an organic SOG material "OCD T-7 5500T" manufactured by Tokyo Ohka Kogyo K.K., diluted with ethanol, was used. Thereafter, an Alq ₃ light emitting layer having an average thickness of 30 nm was formed in the same manner as in Example 5-1 to obtain a light emitting device.

&Lt; Comparative Example 10-3 &

A light emitting device was obtained in the same manner as in Comparative Example 10-2 except that the insulating layer had an average thickness of 30 nm.

&Lt; Comparative Example 10-4 >

A light emitting device was obtained in the same manner as in Comparative Example 10-2 except that the insulating layer had an average thickness of 80 nm.

&Lt; Comparative Example 10-5 >

A light emitting device was obtained in the same manner as in Comparative Example 10-2 except that the insulating layer had an average thickness of 150 nm.

Examples 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, Examples 5-1, 5-2, 5-3, 5-4, 5-5, Example 6-1, 6-2, 6-3, Comparative Examples 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, Comparative Example 5, 6-3, 6-4, 6-5, Comparative Example 7, Comparative Examples 8-1, 8-2, 8-3, Comparative Example 9, Comparative Examples 10-1, 10-2, 10-3, 10-4 and 10-5, the degree of luminescence enhancement was evaluated as follows. 16 (a) showing the measurement system of the light emission spectrum of the photoexcitation light emitting element and FIG. 16 (b) showing the cross section of the photoexcitation light emitting element, the light emitting layer 2 side Excitation light emitting element 1 was caused to emit light by irradiating excitation light 3 from a direction perpendicular to the surface of light emitting layer 2. Light emitted from the excitation light source 4 is condensed by the lens 5 using the UV-LED (UV-LED375-nano manufactured by South Walker, excitation light wavelength 375 nm) ), And this was examined. A wavelength cut filter (not shown) for condensing the light emitted from the photoexcitation light emitting element 1, which is emitted in the direction of 40 degrees with respect to the optical axis of the excitation light 3, in the lens 7 and cutting light having a wavelength of the excitation light 8) (SCF-50 S-44Y, manufactured by Sigma-Aldrich) and detected by a spectrophotometer 9 (MCPD-3000 manufactured by Otsuka Electronics). 16B is a sectional view of a light excitation light source provided with a metal-based particle aggregate thin film 200, an insulating layer 300 and a light emitting layer 2 in this order on a soda glass substrate 100 manufactured in Examples and Comparative Examples. Sectional schematic view showing the light-emitting element 1. Fig.

The integrated value in the light emission wavelength region was obtained with respect to the spectrum of the detected light emission. 4-2, 4-3, 4-4, 4-5, 4-6, and Comparative Examples 4-1, 4-2, 4-3, 4-4, 4-5, A value obtained by dividing the integral value obtained from the light emission spectrum measured for the photoexcitation light emitting element of 4-6 by the integral value obtained from the light emission spectrum measured for the photoexcitation light emitting element of Comparative Example 5 was taken as the " FIG. 17 is a graph showing this as a vertical axis.

Examples 5-1, 5-2, 5-3, 5-4, 5-5, Comparative Examples 6-1, 6-2, 6-3, 6-4, 6-5 and Comparative Examples 10-1, 10-2, 10-3, 10-4, and 10-5 were measured from the emission spectra measured for the photoexcitation light emitting device of Comparative Example 7, and the integral values obtained from the emission spectra measured for the photoexcitation light emitting devices of Examples 10-2, 10-3, Quot; emission enhancement magnification &quot;, and a graph obtained by plotting this as the vertical axis is shown in Fig.

The integrated values obtained from the light emission spectra measured for the photoexcitation light emitting devices of Examples 6-1, 6-2, 6-3, and Comparative Examples 8-1, 8-2, and 8-3 were compared with those of Comparative Example 9 The value obtained by dividing the light-emitting element by the integral value obtained from the light-emitting spectrum measured for the photo-excited light-emitting element is referred to as &quot; luminescence intensification magnification &quot;

1 light excitation light emitting element, 2 light emitting layer, 3 excitation light, 4 excitation light source, 5 and 7 lens, 6 light emission from the light excitation element, 8 wavelength cut filter, 9 spectroscopic detector, 100 soda glass substrate, Layer thin film laminated substrate, 501 substrate, 502 metal particle aggregate thin film, 600 objective lens, 700 spectrophotometer.

Claims (13)

A method for producing a metal-based grain aggregate in which 30 or more metal-based grains are arranged two-dimensionally apart from each other,
Comprising the step of growing metal-based particles at an average height growth rate of less than 1 nm / min on a substrate whose temperature has been adjusted within a range of 100 占 폚 to 450 占 폚. The method of manufacturing a metal-based semiconductor device according to claim 1, wherein in the step of growing the metal-based particles, the metal-based particle has an average height growth rate of less than 1 nm / min and an average height growth rate of less than 5 nm / Min. &Lt; / RTI &gt; The metal-based particle assembly according to claim 1, wherein the metal-based particles constituting the metal-based particle aggregate have an average particle diameter in the range of 200 nm to 1600 nm, an average height in the range of 55 nm to 500 nm, Wherein the aspect ratio defined by the ratio of the particle diameters is in the range of 1 to 8 and the average distance from the adjacent metal particles is in the range of 1 nm to 150 nm. The metal-based particle assembly according to claim 1, wherein the metal-based particles constituting the metal-based particle aggregate have an average particle diameter in the range of 200 nm to 1600 nm, an average height in the range of 55 nm to 500 nm, The aspect ratio defined by the ratio of the particle diameter is in the range of 1 to 8,
The metal-based particle aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particle in the absorption spectrum in the visible light region, Wherein the maximum wavelength of the peak on the longest wavelength side shifts to the short wavelength side in the range of 30 nm to 500 nm as compared with the reference metal-based particle aggregate arranged so as to be in the range of 2 to 2 占 퐉. The metal-based particle assembly according to claim 1, wherein the metal-based particles constituting the metal-based particle aggregate have an average particle diameter in the range of 200 nm to 1600 nm, an average height in the range of 55 nm to 500 nm, The aspect ratio defined by the ratio of the particle diameter is in the range of 1 to 8,
The metal-based particle aggregate preferably has a particle diameter equal to the average particle diameter, a height equal to the average height, and the same material as the metal-based particle in the absorption spectrum in the visible light region, Wherein the absorbance at a maximum wavelength of the peak on the longest wavelength side is higher than that of the reference metal-based particle aggregate arranged so as to be in the range of 2 占 퐉 to 2 占 퐉. The method according to claim 1, wherein the temperature of the substrate in the step of growing the metal-based particles is within a range of 250 캜 to 350 캜. The method according to claim 1, wherein the step of growing the metal-based particles is performed under a pressure of 6 Pa or more. The method of producing a metal-based grain aggregate according to claim 7, wherein the step of growing the metal-based particles is performed under a pressure of 10 Pa or more. The method according to claim 1, wherein the step of growing the metal-based particles is performed by a sputtering method. The method of producing a metal-based particle aggregate according to claim 9, wherein the step of growing the metal-based particles is performed by the DC sputtering method. The method of producing a metal-based particle aggregate according to claim 10, wherein the step of growing the metal-based particles is performed by a direct current argon ion sputtering method. The method of producing a metal-based particle aggregate according to claim 1, wherein the metal-based particles constituting the metal-based particle aggregate are composed of a noble metal. 13. The method of producing a metal-based grain aggregate according to claim 12, wherein the metal-based particles constituting the metal-based grain aggregate are silver.

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