JP2016157009A - Light emitting element and laser device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element capable of amplifying received light energy, and a laser device with the same.SOLUTION: A light emitting element 10 according to the present invention comprises: a light energy receptive polymer sphere 20; and a plurality of light energy donative polymer spheres 30 arranged to contact the energy receptive polymer sphere 20. A light energy donative polymer sphere 30 is made of a pi-conjugated system polymer A with low crystallinity which absorbs light in an ultraviolet to near-infrared range and emits light having a longer wavelength than the absorbed light, and the light energy receptive polymer sphere 20 is made of a pi-conjugated system polymer B with low crystallinity which absorbs light in the same wavelength range with the light that the pi-conjugated system polymer A emits, and emits light having a longer wavelength than the absorbed light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting element and a laser device including the light emitting element.

Light energy collection is a very important process for photosynthesis and solar power generation in plants. In general, the collected light energy becomes excitons in the form of electronic excitation and is collected as energy. However, since the exciton diffusion length is usually several nanometers to several tens of nanometers, the range in which light can be collected is very narrow. Therefore, a light energy collecting system that can collect light over a wide range is expected.
What is expected as a light energy collection system includes, for example, a phenomenon called resonance energy transfer (FRET) from an energy donating molecule to an energy accepting molecule (for example, non-patented). References 1 and 2).

Robert S. Knox, “Forster's resonance excitement transfer theory: not just a formula” Journal of Biomedical Optics 17 (1), 011003 (January 2012). Luis Cerdan et al. , “FRET-assisted laser emission in colloidal suspensions of dyed-latex nanoparticulates” Nature Photonics. 19 August 2012, 621-626. Theodor Forster, "Experimentale un theoretische Unteruchung des zwischenmolenularen bergangs von Elektroennanregungsengerge." 1949, 321-327.

  However, even in a light energy collecting system using a phenomenon called FRET, the range in which light can be collected is about several nm to several tens of nm.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the light emitting element which can amplify the received light energy, and a laser device provided with the same.

  The light emitting device of the present invention comprises a light energy accepting polymer sphere, and a plurality of light energy donating polymer spheres arranged to contact the energy accepting polymer sphere, wherein the light energy donating polymer sphere comprises: It comprises a pi-conjugated polymer A that absorbs light in the ultraviolet to near-infrared region and emits light having a longer wavelength than the absorbed light, and has low crystallinity. It is characterized by comprising a pi-conjugated polymer B having low crystallinity that absorbs light in the same wavelength range as the light emitted from the polymer A and emits light having a longer wavelength than the absorbed light.

  In the light emitting device of the present invention, the light energy accepting polymer sphere and the light energy donating polymer sphere are preferably disposed on the same plane.

  In the light emitting device of the present invention, it is preferable that the fluorescence quantum yield of the pi-conjugated polymer A and the pi-conjugated polymer B is 1% or more.

  A laser device according to the present invention includes the light emitting element according to the present invention.

  According to the present invention, the light energy generated by the plurality of light energy donating polymer spheres arranged so as to be in contact with the energy receptive polymer sphere can be concentrated on the light energy receptive polymer sphere. The received light energy can be amplified.

It is a schematic perspective view which shows the 1st example of the light emitting element which is one Embodiment of this invention. It is a schematic perspective view which shows the 2nd example of the light emitting element which is one Embodiment of this invention. It is a figure which shows the absorption spectrum of PDOF-TPD, and the absorption spectrum of PBDTC-Cz. It is a schematic diagram which shows the manufacturing method of the light emitting element which is one Embodiment of this invention. It is a schematic perspective view which shows the manufacturing method of the light emitting element which is one Embodiment of this invention. It is a schematic perspective view which shows the manufacturing method of the light emitting element which is one Embodiment of this invention. It is a schematic perspective view which shows the manufacturing method of the light emitting element which is one Embodiment of this invention. It is a schematic diagram which shows the apparatus of the microphotoluminescence used by the experiment example. It is the optical photograph which image | photographed the light emitting element when not irradiating a laser beam. It is the optical photograph which image | photographed the light emitting element at the time of irradiating a laser beam. It is the optical photograph which image | photographed the light emitting element at the time of irradiating a laser beam. It is the optical photograph which image | photographed the light emitting element at the time of irradiating a laser beam. It is a figure which shows the result of having measured the spectrum of the light light-emitted from the light emitting element.

Embodiments of a light emitting device of the present invention and a laser device including the light emitting device will be described.
Note that this embodiment is specifically described in order to better understand the gist of the invention, and does not limit the present invention unless otherwise specified.

[Light emitting element]
The light emitting device of this embodiment includes a light energy accepting polymer sphere and a plurality of light energy donating polymer spheres arranged so as to be in contact with the energy accepting polymer sphere. The light energy donating polymer sphere is composed of a pi-conjugated polymer A that absorbs light in the ultraviolet to near infrared region and emits light having a longer wavelength than the absorbed light and has low crystallinity. The light energy-receptive polymer sphere absorbs light in the same wavelength region as the light emitted from the pi-conjugated polymer A, and emits light having a longer wavelength than the absorbed light. Consists of conjugated polymer B.

Hereinafter, the light emitting device of this embodiment will be described with reference to FIG.
FIG. 1 is a schematic perspective view showing a first example of the light emitting device of this embodiment. FIG. 2 is a schematic perspective view showing a second example of the light emitting device of this embodiment.
The light emitting device 10 of the present embodiment is generally configured by a light energy accepting polymer sphere 20 and a plurality of light energy donating polymer spheres 30 arranged so as to be in contact with the energy accepting polymer sphere 20. That is, in the light emitting element 10, a plurality of light energy donating polymer spheres 30 are arranged around the light energy receptive polymer sphere 20 with the light energy receptive polymer sphere 20 as the center.

In the first example shown in FIG. 1, five light energy donating polymer spheres 30 are arranged around one light energy accepting polymer sphere 20.
It is preferable that the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 are arranged on the same plane. In this way, the supply (transfer) of light energy from the light energy donating polymer sphere 30 to the light energy accepting polymer sphere 20 can be performed efficiently.

The five light energy donating polymer spheres 30 are arranged such that the surface (outer peripheral surface) 30a of the light energy donating polymer sphere 30 is in contact with the surface (outer peripheral surface) 20a of the light energy accepting polymer sphere 20. Has been. Further, the five light energy donating polymer spheres 30 are arranged close to each other in contact with the light energy accepting polymer sphere 20.
When the five light energy donating polymer spheres 30 are arranged close to each other, a gap 40 exists between the respective light energy donating polymer spheres 30. The five light energy donating polymer spheres 30 may be arranged so as to be in contact with each other at their respective surfaces (outer peripheral surfaces) 30a.

  In the second example shown in FIG. 2, six light energy donating polymer spheres 30 </ b> A (30) are arranged around one light energy accepting polymer sphere 20. Further, at least one other light energy donating polymer sphere 30 </ b> B (30) is in contact with the light energy donating polymer sphere 30 </ b> A on the side opposite to the light energy accepting polymer sphere 20. In addition, another light energy donating polymer sphere (not shown) may be in contact with the light energy donating polymer sphere 30B on the side opposite to the light energy accepting polymer sphere 20. As described above, in the light emitting element 10, a plurality of light energy donating polymer spheres 30 may be arranged around the one light energy accepting polymer sphere 20 around the light receiving element sphere 20. The light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 are preferably disposed on the same plane.

The six light energy donating polymer spheres 30A are arranged so that the surface (outer peripheral surface) 30a of the light energy donating polymer sphere 30A is in contact with the surface (outer peripheral surface) 20a of the light energy accepting polymer sphere 20. Has been. The six light energy donating polymer spheres 30 </ b> A are arranged close to each other in contact with the light energy accepting polymer sphere 20.
When the six light energy donating polymer spheres 30A are arranged close to each other, a gap 40 exists between the respective light energy donating polymer spheres 30A. The six light energy donating polymer spheres 30A may be disposed so as to be in contact with each other on the respective surfaces (outer peripheral surfaces) 30a.

  Further, as shown in FIG. 2, the light energy donating polymer sphere 30B is disposed so as to be in contact with two adjacent light energy donating polymer spheres 30A. In the case where a plurality of light energy donating polymer spheres 30 (30A, 30B) are arranged around the light energy receptive polymer sphere 20, the plurality of light energy donating polymer spheres 30 are It is preferable that they are arranged closest on the same surface.

  In the light emitting device 10 shown in FIGS. 1 and 2, when the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 are arranged on the same plane, that is, the light energy accepting polymer sphere 20 and Although the case where the light energy donating polymer spheres 30 are two-dimensionally arranged is illustrated, the light emitting device of the present invention is not limited to this. In the light emitting device of the present invention, the light energy accepting polymer sphere and the light energy donating polymer sphere may be three-dimensionally arranged.

  In the light emitting device 10 shown in FIGS. 1 and 2, the case where a plurality of light energy donating polymer spheres 30 having substantially the same particle diameter are arranged with respect to the light energy accepting polymer sphere 20 is illustrated. The light emitting device of the present invention is not limited to this. In the light emitting device of the present invention, light energy donating polymer spheres having a particle diameter smaller than these are disposed (filled) in a gap between a plurality of light energy donating polymer spheres having substantially the same particle diameter. It may be. In this way, the supply (transfer) of light energy from the light energy donating polymer sphere 30 to the light energy accepting polymer sphere 20 can be performed efficiently.

The light energy receptive polymer sphere 20 and the light energy donating polymer sphere 30 are each a sphere composed of independent primary particles, and is not a sphere composed of secondary particles in which the primary particles are aggregated.
The average particle diameter of the light energy receptive polymer sphere 20 is preferably 1 μm to 50 μm, and more preferably 2 μm to 10 μm.
The average particle diameter of the light energy donating polymer sphere 30 is preferably 1 μm to 50 μm, and more preferably 2 μm to 10 μm.

In the present embodiment, the pi-conjugated polymer A having low crystallinity that forms the light energy donating polymer sphere 30 and the pi-conjugated polymer B having low crystallinity that constitutes the light energy accepting polymer sphere 20 are It is a pi-conjugated polymer that forms a spherical structure in a solvent. Since a polymer having high crystallinity is anisotropic, the crystal also grows anisotropically. Therefore, a polymer having high crystallinity does not form a spherical structure. On the other hand, since a polymer with low crystallinity is not anisotropic, the crystal grows isotropically. Therefore, a polymer having low crystallinity forms a spherical structure (isotropic structure).
To confirm whether or not the pi-conjugated polymer forms a spherical structure in the solvent, dissolve the pi-conjugated polymer in chloroform or the like, and vapor diffuse the methanol or the like that is a poor solvent with high polarity. For example, a method of slowly observing a deposited structure by an electron microscope or an optical microscope may be used.

In addition, the pi-conjugated polymer A having low crystallinity that forms the light energy donating polymer sphere 30 in the present embodiment absorbs light in the ultraviolet to near-infrared region, and emits light having a longer wavelength than the absorbed light. Have the property of emitting light.
The fluorescence quantum yield of the pi-conjugated polymer A is preferably 1% or more, and more preferably 10% or more. When the fluorescence quantum yield of the pi-conjugated polymer A is 1% or more, not only the energy transfer efficiency is improved, but also damage to the device due to thermal deactivation can be reduced.

Note that the fluorescence quantum yield (%) of the pi-conjugated polymer A is calculated from the number of photons absorbed by the pi-conjugated polymer A and the emission from the pi-conjugated polymer A as shown in the following formula (a). It is obtained as a ratio to the number of photons generated.
Fluorescence quantum yield (%) = “number of photons emitted from pi-conjugated polymer A” / “number of photons absorbed by pi-conjugated polymer A” × 100 (a)
The closer the fluorescence quantum yield is to 100%, the higher the efficiency of light emission as fluorescence from the pi-conjugated polymer A.

  As such pi-conjugated polymer A, for example, poly [(9,9-dioctylfluorene-2,7-diyl)-(5-octylthieno- [3,4-c] represented by the following formula (1): ] Pyrrole-4,6-dione-1,3-diyl)] (PDOF-TPD, absorption (excitation) wavelength: 470 nm, emission wavelength: 540 nm, fluorescence quantum yield: 17.2%), the following formula (2 ) Poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt- (3,3 ′, 4,4′-tetramethylbithiophene-2,5′-diyl)] (PDOF-TMT2, absorption ( Excitation) wavelength: 370 nm, emission wavelength: 460 nm, fluorescence quantum yield: 2.4%) and the like.

Further, the pi-conjugated polymer B with low crystallinity that forms the light energy-receptive polymer sphere 20 in the present embodiment absorbs light in the same wavelength region as the light emitted by the pi-conjugated polymer A, and absorbs the light. It has the property of emitting light having a wavelength longer than that of the emitted light.
Further, the fluorescence quantum yield of the pi-conjugated polymer B is preferably 1% or more, and more preferably 10% or more. When the fluorescence quantum yield of the pi-conjugated polymer B is 1% or more, not only the energy transfer efficiency is improved, but also damage to the device due to thermal deactivation can be reduced.
The fluorescence quantum yield (%) of the pi-conjugated polymer B is determined in the same manner as the fluorescence quantum yield of the pi-conjugated polymer A.

  As such a pi-conjugated polymer B, for example, poly [N- (2-heptyldecyl) carbazole-2,7-diyl-alt-4,8-bis [(dodecyl) represented by the following formula (3): ) Carbonyl] benzo [1,2-b: 4,5 \ b '] dithiophene-2,6-diyl] (PBDTC-Cz, absorption (excitation) wavelength: 530 nm, emission wavelength: 620 nm, fluorescence quantum yield: 19 0.1%), poly [N- (4-octylphenyl) iminoazobenzene-4,4′-diyl] represented by the following formula (4) (AZO-ANI, absorption (excitation) wavelength: 550 nm, emission wavelength: 680 nm, Fluorescence quantum yield: 1.2%) and the like.

As such a combination of the pi-conjugated polymer A and the pi-conjugated polymer B, for example, a combination in which the pi-conjugated polymer A is PDOF-TPD and the pi-conjugated polymer B is PBDTC-Cz, The pi-conjugated polymer A is PDOF-TPD, the pi-conjugated polymer B is AZO-ANI, the pi-conjugated polymer A is PDOF-TMT2, and the pi-conjugated polymer B is PBDTC-Cz. And a combination in which the pi-conjugated polymer A is PDOF-TMT2 and the pi-conjugated polymer B is AZO-ANI.
As shown in FIG. 3, since the absorption spectrum of PDOF-TPD and the absorption spectrum of PBDTC-Cz overlap, it is considered that the transfer of light energy from PDOF-TPD to PBDTC-Cz occurs efficiently.

Next, the operation of the light emitting element 10 of this embodiment will be described.
As shown in FIGS. 1 and 2, when the light α is irradiated to the light emitting element 10, the light energy donating polymer sphere 30 made of the pi-conjugated polymer A absorbs the light α. Then, the light energy donating polymer sphere 30 emits light β having a wavelength longer than that of the absorbed light α, and the light β is a light energy called Whispering Gallery Mode (WG mode). The traveling wave 31 propagates in the circumferential direction of the donating polymer sphere 30 and becomes confined in the light energy donating polymer sphere 30. Here, the light α is light in the ultraviolet to near infrared region.

  When the light energy donating polymer sphere 30 exists alone, the traveling wave 31 (light β) is confined in the light energy donating polymer sphere 30 as it is and propagates in the circumferential direction of the light energy donating polymer sphere 30. . In the light emitting element 10, since the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 are in contact with each other, a traveling wave 31 (light β) is generated from the light energy donating polymer sphere 30 to the light energy accepting polymer sphere 20. Donated (moved).

  When the light β moves to the light energy receptive polymer sphere 20, the light energy receptive polymer sphere 20 made of the pi-conjugated polymer B absorbs the light β. Then, the light energy receptive polymer sphere 20 emits light γ having a longer wavelength than the absorbed light β, but the light γ propagates in the circumferential direction of the light energy receptive polymer sphere 20, which is called a WG mode. The traveling wave 21 is trapped in the light energy receptive polymer sphere 20. That is, the light energy accepting polymer sphere 20 emits light (colors corresponding to the wavelength of the light γ) by the light γ.

  At this time, for example, when the excitation intensity per pulse is increased with a pulse laser having a short pulse width as the excitation light, a large number of photons having the same energy, phase, and traveling direction are stimulated and emitted to cause laser oscillation from the light emitting element 10. be able to.

  The movement of the light β as described above occurs from all the light energy donating polymer spheres 30 in contact with the light energy accepting polymer sphere 20 to the light energy accepting polymer sphere 20. That is, in the light emitting element 10 shown in FIG. 1, the light β moves from the five light energy donating polymer spheres 30 to the light energy accepting polymer sphere 20. In the light emitting element 10 shown in FIG. 2, the light β moves from the six light energy donating polymer spheres 30 to the light energy accepting polymer sphere 20. As described above, in the light emitting element 10, the light β moves from all the light energy donating polymer spheres 30 in contact with the light energy accepting polymer sphere 20 disposed at the center. That is, all of the light energy generated in the plurality of light energy donating polymer spheres 30 is concentrated on the light energy accepting polymer sphere 20. Therefore, the light energy in the light energy receptive polymer sphere 20 has a higher energy level than the light energy of each of the five light energy donating polymer spheres 30 arranged around the light energy receptive polymer sphere 20.

  In addition, as shown in FIG. 2, when a plurality of light energy donating polymer spheres 30 are arranged around the light energy receptive polymer sphere 20, for example, the light energy receptive polymer spheres, for example, The light β emitted from the light energy donating polymer sphere 30B not in contact with 20 moves to the adjacent light energy donating polymer sphere 30B, or the light energy donating property in contact with the light energy accepting polymer sphere 20 It moves to the polymer sphere 30A and finally moves to the light energy accepting polymer sphere 20. As described above, when a plurality of light energy donating polymer spheres 30 are arranged so as to be connected to the periphery of the light energy receptive polymer sphere 20, more light β (light energy) is The light energy-receptive polymer sphere 20 can be concentrated.

  Further, since the light energy generated by the plurality of light energy donating polymer spheres 30 arranged around the light energy accepting polymer sphere 20 can be concentrated, the light α irradiated to the entire light emitting element 10 can be concentrated. Even if the energy (intensity) is low, the light energy caused by the light α is concentrated from the plurality of light energy donating polymer spheres 30 to the light energy accepting polymer sphere 20, so that the light energy received by the light emitting element 10 is received. Can be amplified. Therefore, the energy of the light α irradiated to the entire light emitting element 10 can be lowered, and therefore the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 can be prevented from being deteriorated by the light α.

In the present embodiment, the case where the light emitting element 10 includes only the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 is illustrated, but the light emitting element of the present invention is not limited thereto. In the light emitting device of the present invention, the light energy accepting polymer sphere and the light energy donating polymer sphere may be disposed on one surface of the substrate.
As the substrate, a silicon substrate, a quartz substrate, a glass substrate, a sapphire substrate, a mica substrate, or the like is used. Further, one surface of the substrate may not be subjected to surface treatment, or may be subjected to at least one of hydrophobic treatment and hydrophilic treatment.

[Method for Manufacturing Light-Emitting Element]
Next, with reference to FIGS. 4-7, the manufacturing method of the light emitting element of this embodiment is demonstrated.
The light emitting element manufacturing method of the present embodiment includes, for example, a step of producing a light energy accepting polymer sphere 20, a step of producing a light energy donating polymer sphere 30, and the light energy accepting polymer sphere 20 and the light energy donating. Disposing the conductive polymer sphere 30 on the substrate.

In the step of producing the light energy receptive polymer sphere 20, the light energy receptive polymer sphere 20 is produced by a vapor diffusion method described later.
First, the above-described pi-conjugated polymer B having low crystallinity, which is a raw material of the light energy-receptive polymer sphere 20, is dissolved in a good solvent to prepare a solution containing the pi-conjugated polymer B.
As the good solvent, for example, chloroform, dichloromethane, toluene, tetrahydrofuran, orthodichlorobenzene and the like are used.
The concentration of the solution containing the pi-conjugated polymer B is not particularly limited, and is, for example, 0.1 mg / mL to 10.0 mg / mL.

Next, as shown in FIG. 4, a container 80 smaller than the sealed container 60 containing the solution 70 containing the pi-conjugated polymer B is placed in the center of the sealed container 60 containing the poor solvent 50, and the temperature is kept constant. Leave in a cage at 25 ° C. for 1-7 days.
At this time, the container 80 is kept open without being covered.

Further, the amount (volume) of the poor solvent 50 is set to be larger than the amount (volume) of the solution 70. For example, the amount of the poor solvent 50 and the amount of the solution 70 are 10: 1 to 10:10 by volume ratio.
As the poor solvent, for example, acetonitrile, methanol, acetone, water or the like is used.

  Since the solution 70 contains the pi-conjugated polymer B, the vapor pressure is lower than that of the poor solvent 50. Therefore, the vapor of the poor solvent 50 gradually moves (mixes) into the solution 70 in the container 80 so that the vapor pressure of the solution 70 becomes equal to the vapor pressure of the poor solvent 50. As a result, a structure composed of the pi-conjugated polymer B gradually precipitates in the solution 70. Since this structure becomes a thermally re-stable structure, it becomes a spherical structure, that is, the above-described light energy receiving polymer sphere 20.

In the step of producing the light energy donating polymer sphere 30, the light energy donating polymer sphere 30 is produced by the vapor diffusion method described later.
First, the above-described pi-conjugated polymer A having low crystallinity, which is a raw material of the light energy donating polymer sphere 30, is dissolved in a good solvent to prepare a solution containing the pi-conjugated polymer A.
As the good solvent, for example, chloroform, dichloromethane, toluene, tetrahydrofuran, orthodichlorobenzene and the like are used.
The concentration of the solution containing the pi-conjugated polymer A is not particularly limited, and is, for example, 0.1 mg / mL to 10.0 mg / mL.

Next, as shown in FIG. 4, a container 80 smaller than the sealed container 60 containing the solution 70 containing the pi-conjugated polymer A is placed in the center of the sealed container 60 containing the poor solvent 50, and the temperature is kept constant. Leave in a cage at 25 ° C. for 1-7 days.
At this time, the container 80 is kept open without being covered.

Further, the amount (volume) of the poor solvent 50 is set to be larger than the amount (volume) of the solution 70. For example, the amount of the poor solvent 50 and the amount of the solution 70 are 10: 1 to 10:10 by volume ratio.
As the poor solvent, for example, methanol, acetonitrile, acetone, water or the like is used.

  Since the solution 70 contains the pi-conjugated polymer A, the vapor pressure is lower than that of the poor solvent 50. Therefore, the vapor of the poor solvent 50 gradually moves (mixes) into the solution 70 in the container 80 so that the vapor pressure of the solution 70 becomes equal to the vapor pressure of the poor solvent 50. As a result, a structure composed of the pi-conjugated polymer A gradually precipitates in the solution 70. Since this structure becomes a thermally re-stable structure, it becomes a spherical structure, that is, the above-described light energy donating polymer sphere 30.

In the step of arranging the light energy accepting polymer sphere 20 and the light energy donating polymer sphere 30 on the substrate, first, as shown in FIG. The suspension 110 of the conductive polymer sphere 20 is dropped.
The content of the light energy accepting polymer sphere 20 in the suspension 110 is not particularly limited, but is preferably 0.01% by mass to 2.0% by mass, and 0.1% by mass to 1.0% by mass. It is more preferable that

  Next, the suspension 110 is dried using a vacuum pump, and the light energy receiving polymer sphere 20 is fixed to the one surface 90 a of the substrate 90.

Next, as shown in FIG. 6, the suspension 120 of the light energy donating polymer sphere 30 is spin-coated on the one surface 90a of the substrate 90 on which the light energy accepting polymer sphere 20 is fixed.
At this time, the suspension 120 is applied so that the suspension 120 covers the light energy receiving polymer sphere 20 on the one surface 90 a of the substrate 90.
The content of the light energy donating polymer sphere 30 in the suspension 120 is not particularly limited, but is preferably 0.01% by mass to 2.0% by mass, and 0.1% by mass to 1.0% by mass. It is more preferable that

  Next, the suspension 120 is dried using a vacuum pump, and the light energy donating polymer sphere 30 is fixed to the one surface 90 a of the substrate 90. Accordingly, the plurality of light energy donating polymer spheres 30 are arranged so as to be in contact with the energy receiving polymer spheres 20. Then, as shown in FIG. 7, the substrate 90, the light energy receptive polymer sphere 20 fixed to one surface 90 a of the substrate 90, and the one surface 90 a of the substrate 90 are fixed so as to contact the energy receptive polymer sphere 20. A light emitting device 130 having a plurality of arranged light energy donating polymer spheres 30 is obtained.

[Laser device]
The laser device of this embodiment includes the light-emitting element 10 of the above-described embodiment. In other words, the laser device of the present embodiment includes the above-described light emitting element 10 of the present embodiment as an amplifier, for example.
As described above, the light emitting element 10 according to the present embodiment converts the light energy caused by the light to the plurality of light energy donating polymer spheres 30 even when the energy (intensity) of the light applied to the entire light emitting element 10 is low. The energy of the emitted light can be amplified by concentrating on the light energy accepting polymer sphere 20. Therefore, when the laser device of the present embodiment includes the light emitting element 10 of the present embodiment as an amplifier, a laser device capable of laser oscillation can be realized even when the energy of light from the light source is low.

  Hereinafter, the present invention will be described more specifically with experimental examples, but the present invention is not limited to the following experimental examples.

[Experimental example]
"Production of light energy receptive polymer sphere"
PBDTC-Cz used as a raw material for the light energy-receptive polymer sphere was dissolved in chloroform to prepare a solution containing PBDTC-Cz.
The concentration of the solution containing PBDTC-Cz was 0.5 mg / mL.
Next, a container containing 2 mL of a solution containing PBDTC-Cz was placed in the center of a sealed container containing 5 mL of acetonitrile, and left in a constant temperature bath at 25 ° C. for 1 day. At this time, the container was opened without a lid.
In the sealed container, the vapor of acetonitrile gradually moved to the solution containing PBDTC-Cz in the container, and light energy-receptive polymer spheres composed of PBDTC-Cz were deposited in the solution.

“Preparation of light energy donating polymer sphere”
PDOF-TPD as a raw material for the light energy donating polymer sphere was dissolved in chloroform to prepare a solution containing PDOF-TPD.
The concentration of the solution containing PDOF-TPD was 0.5 mg / mL.
Next, a container containing 2 mL of a solution containing PDOF-TPD was placed in the center of a sealed container containing 5 mL of methanol, and left in a constant temperature bath at 25 ° C. for 1 day. At this time, the container was opened without a lid.
In the sealed container, the vapor of methanol gradually moved to the solution containing PDOF-TPD in the container, and light energy donating polymer spheres composed of PDOF-TPD were deposited in the solution.

"Production of light-emitting elements"
Next, suspension A of light energy-receptive polymer spheres made of PBDTC-Cz was dropped onto one surface of the quartz substrate using a microsyringe.
Next, the suspension A was dried using a vacuum pump, and the light energy-receptive polymer spheres were fixed to one surface of the quartz substrate.
Next, a suspension B of light energy donating polymer spheres made of PDOF-TPD was spin-coated at 3000 rpm for 60 seconds on one surface of the quartz substrate on which the light energy accepting polymer spheres were fixed. At this time, the suspension B was applied so that the suspension B covered the light energy receiving polymer sphere on one surface of the quartz substrate.
Next, the suspension B was dried using a vacuum pump, and the light energy donating polymer spheres were fixed to one surface of the quartz substrate. Thereby, a quartz substrate, a light energy receiving polymer sphere fixed to one surface of the quartz substrate, and a plurality of light energy donating polymers fixed to one surface of the quartz substrate and arranged so as to contact the energy receiving polymer sphere A light emitting element including a sphere was obtained.

"Evaluation"
The obtained light-emitting element was evaluated using a microphotoluminescence apparatus 200 as shown in FIG.

The apparatus 200 includes an XY stage 210 having a placement surface 210a on which the light emitting element 10 is placed, and a CW laser (continuous) that irradiates the light emitting element 10 placed on the placement surface 210a of the XY stage 210 with a laser beam α ′. (Wave Laser) 220, a spectroscope 230 that measures the spectrum of the light β ′ emitted from the light emitting element 10, and a CCD camera 240 that observes (photographs) the light β ′ from the light emitting element 10.
The CCD camera 240 is disposed so as to face the mounting surface 210a of the XY stage 210 with an interval. In addition, the CCD camera 240 is arranged such that the emission direction of the light β ′ from the light emitting element 10 and the light incident surface of the imaging element (not shown) are perpendicular to each other.

On the optical path of the light β ′ between the mounting surface 210a of the XY stage 210 and the CCD camera 240, that is, on the optical path of the light β ′ from the light emitting element 10 to the CCD camera 240, a predetermined interval is placed in order from the XY stage 210 side. One half mirror 251 and a second half mirror 252 are arranged. The first half mirror 251 and the second half mirror 252 are arranged such that the respective reflecting surfaces 251a and 252a are inclined by 45 degrees with respect to the optical path of the light β ′ from the light emitting element 10 to the CCD camera 240.
Further, an objective lens capable of adjusting the position in the Z-axis direction (perpendicular to the placement surface 210a of the XY stage 210) between the placement surface 210a of the XY stage 210 and the first half mirror 251. 260 is arranged.

The CW laser 220 is disposed so as to face the first half mirror 251 with a gap. Further, the CW laser 220 is disposed at a position where the emission direction of the laser light α ′ and the optical path of the light β ′ from the light emitting element 10 to the CCD camera 240 are perpendicular to each other.
A laser filter 270 and an intensity adjustment filter 280 are arranged between the CW laser 220 and the first half mirror 251 at a predetermined interval in order from the CW laser 220 side.

The spectroscope 230 is disposed so as to face the second half mirror 252 with a space therebetween. The spectroscope 230 is arranged at a position where the reflection direction of the light β ′ reflected by the second half mirror 252 and the optical path of the light β ′ from the light emitting element 10 to the CCD camera 240 are perpendicular to each other.
A long pass filter 290 is disposed between the spectroscope 230 and the second half mirror 252.

The XY stage 210 is movable by a manipulator in the X-axis direction (direction parallel to the placement surface 210a of the XY stage 210) and the Y-axis direction (direction parallel to the placement surface 210a of the XY stage 210). Yes.
The objective lens 260 can focus the laser light α ′ (wavelength 532 nm) from the CW laser 220 to a spot having a diameter of 1 μm or less. Thereby, the light emitting element 10 can be partially photoexcited.

Next, an outline of the operation of the apparatus 200 will be described.
First, the light emitting element 10 is mounted on the mounting surface 210 a of the XY stage 210. In the light emitting element 10, the XY stage 210 is moved so that the laser light α ′ is irradiated to a position where light excitation is desired, and the light emitting element 10 is aligned with the objective lens 260.
When the laser light α ′ from the CW laser 220 is emitted, the laser light α ′ passes through the laser filter 270 and the intensity adjustment filter 280 and reaches the reflecting surface 251a of the first half mirror 251. The laser light α ′ is reflected by the reflection surface 251 a of the first half mirror 251 toward the placement surface 210 a of the XY stage 210 and enters the objective lens 260. The laser light α ′ incident on the objective lens 260 is incident on the light emitting element 10 mounted on the mounting surface 210 a of the XY stage 210. At this time, the objective lens 260 is moved in the Z-axis direction, the distance (interval) between the objective lens 260 and the light emitting element 10 is adjusted, and the laser light α ′ is focused to a spot, so that the light emitting element 10 can be moved to an arbitrary position. Laser light α ′ is irradiated. Then, the pi-conjugated polymer at the position irradiated with the laser beam α ′ is excited and emits light β ′ having a longer wavelength than the laser beam α ′. The light β ′ is transmitted through the objective lens 260 and the first half mirror 251, partially reflected by the second half mirror 252 to the spectroscope 230 side, and incident on the spectroscope 230, and the rest is the first. 2 passes through the half mirror 252 and enters the image sensor of the CCD camera 240. Then, the spectrum of the light β ′ is measured by the spectroscope 230, and the light β ′ is observed (photographed) by the CCD camera 240.

Here, the intensity of the laser light α ′ is 1 μW, and the irradiation time of the laser light α ′ on the light emitting element 10 is 0.001 second.
In addition, the irradiation position of the laser light α ′ in the light emitting element 10 is the light energy accepting polymer sphere only (a) in the system where the light energy accepting polymer sphere and the light energy donating polymer sphere are in contact with each other. Only the polymer sphere (b), the whole of the light energy accepting polymer sphere and the light energy donating polymer sphere (c). The spectrum of the light β ′ from the light emitting element 10 is measured by the spectroscope 230 of the apparatus 200 for each of the cases where the laser light α ′ is irradiated to the positions (a), (b), and (c). At the same time, the light β ′ was observed (photographed) by the CCD camera 240. Optical photographs taken of the light emitting element 10 are shown in FIG. 9 to FIG. 12, and each of the cases where the laser light α ′ is irradiated to the positions (a), (b) and (c) above, from the light emitting element 10. The result of measuring the spectrum of light β ′ is shown in FIG. The photographing magnification of the optical photographs shown in FIGS. 9 to 12 is 2000.

  FIG. 9 is an optical photograph obtained by photographing the light energy accepting polymer sphere and the light energy donating polymer sphere in the light emitting element 10 when the laser beam α ′ is not irradiated. In this case, the light energy accepting polymer sphere and the light energy donating polymer sphere do not emit light.

  FIG. 10 is an optical photograph obtained by photographing the light energy accepting polymer sphere and the light energy donating polymer sphere when only the light energy accepting polymer sphere (a) of the light emitting element 10 is irradiated with the laser light α ′. is there. In this case, the light energy donating polymer sphere itself does not emit light, but the light energy accepting polymer sphere is excited and emits red light, and the red light propagates to the light energy donating polymer sphere, and thus the light energy donating polymer sphere. It was observed that the polymer sphere glowed red.

  FIG. 11 is an optical photograph obtained by photographing the light energy accepting polymer sphere and the light energy donating polymer sphere when only the light energy donating polymer sphere (b) of the light emitting element 10 is irradiated with the laser light α ′. is there. In this case, the light energy donating polymer sphere is excited to emit yellow light, the yellow light propagates to the light energy accepting polymer sphere, and the light energy accepting polymer sphere excited by the yellow light emits red light. It was observed that light was emitted.

  FIG. 12 shows the light energy accepting polymer sphere and the light energy donating property when the entire light energy accepting polymer sphere and the light energy donating polymer sphere (c) of the light emitting element 10 are irradiated with the laser light α ′. It is the optical photograph which image | photographed the polymer sphere. In this case, it is observed that the light energy accepting polymer sphere is excited to emit red light, the red light propagates to the light energy donating polymer sphere, and the light energy donating polymer sphere glows red. It was. Also, the light energy donating polymer sphere is excited to emit yellow light, the yellow light propagates to the light energy accepting polymer sphere, and the light energy accepting polymer sphere excited by the yellow light emits red light. It was observed that That is, light emission from the entire light energy accepting polymer sphere and the light energy donating polymer sphere was mainly red light.

  The light emitting device of the present invention can concentrate light energy generated by a plurality of light energy donating polymer spheres arranged so as to be in contact with the energy receiving polymer sphere on the light energy receiving polymer sphere. Since the light energy received by can be amplified, it can be applied to uses as a laser device such as a laser oscillation element.

DESCRIPTION OF SYMBOLS 10 ... Light emitting element, 20 ... Light energy receptive polymer sphere, 30 ... Light energy donating polymer sphere, 40 ... Gap, 50 ... Poor solvent, 60 ... Sealed container, 70 ... Solution, 80 ... Container, 90 ... Substrate, 100 ... Micro syringe, 110, 120 ... Suspension.

Claims (4)

A light energy accepting polymer sphere, and a plurality of light energy donating polymer spheres arranged to contact the energy accepting polymer sphere,
The light energy donating polymer sphere is composed of a pi-conjugated polymer A having a low crystallinity that absorbs light in the ultraviolet to near infrared region and emits light having a longer wavelength than the absorbed light.
The light energy-receptive polymer sphere absorbs light in the same wavelength region as the light emitted from the pi-conjugated polymer A, and emits light having a longer wavelength than the absorbed light. A light-emitting element comprising the polymer B.   The light emitting element, wherein the light energy accepting polymer sphere and the light energy donating polymer sphere are arranged on the same plane.   3. The light emitting device according to claim 1, wherein a fluorescence quantum yield of the pi-conjugated polymer A and the pi-conjugated polymer B is 1% or more.   A laser device comprising the light-emitting element according to claim 1.