JP2008050531A - Luminescent material for organic solid laser and organic solid laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminescent material for organic solid laser emitting blue laser light having a low ASE (amplified spontaneous emission) oscillation threshold and a high ASE gain. <P>SOLUTION: The luminescent material for organic solid laser comprises a fluorene compound represented by general formula (1). (In the formula, R<SP>1</SP>, R<SP>2</SP>are each independently H, a halogen atom, a 1-18C linear, branched or cyclic alkyl group, or a 6-40C aryl group, R<SP>1</SP>and R<SP>2</SP>may bond each other to form a ring. Q<SP>1</SP>and Q<SP>2</SP>are each independently a (substituted) 6-40C aryl group or 4-40C heteroaryl group.). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting material for an organic solid-state laser. The present invention also relates to an organic solid-state laser characterized in that a fluorene compound is contained in the light emitting layer.

Lasers are one of the key devices for high-speed, large-capacity optical information communication technology. For example, an inorganic semiconductor laser is currently used as a laser for optical information communication, but the laser wavelength is limited and high cost due to a complicated manufacturing process is a problem. In recent years, by using organic solid compounds for materials such as laser active layers, optical waveguides, and optical resonators, it is possible to emit lasers having a larger number of wavelengths compared to inorganic semiconductor lasers, and with simple and fewer processes. Organic solid-state lasers are attracting attention because of their ability to be manufactured. An organic solid-state laser emits light by recombination of holes and electrons in the light emitting layer by injecting holes from the anode into the light emitting layer and applying electrons from the cathode by applying voltage. Is amplified by being guided in the laser device and emitted as laser light. In recent years, the development of organic solid-state lasers has progressed, but it has still been overcome such as achievement of high current density (several kA / cm ² ), search for organic laser light-emitting materials with low thresholds, construction of current-excitable structures, etc. There are many issues to be solved.

So far, many compounds have been proposed as organic laser light-emitting materials. For example, Patent Document 1 discloses a paraphenylene compound, a benzothiazole compound, a benzimidazole compound, a benzoxazole compound, a metal chelated oxinoid compound, a styrylbenzene compound, an aromatic dimethylidin compound, a styrylamine compound, and a phenolate as organic laser light emitting materials. An aluminum complex in which a ligand and a substituted quinolylate ligand are bonded is described.
Patent Document 2 describes a boron-containing stilbene derivative, and Patent Document 3 exemplifies a co-oligomer compound having a structure in which thiophene and a phenylene or phenyl group are directly bonded.
Non-Patent Document 1, ASE (amplified spontaneous emission = A mplified s pontaneous E mission) oscillation threshold 1 .mu.J / cm ² or less of BSBCz (4,4'- bis [(N-carbazole) styryl] biphenyl, the following chemical formula (A)) and BSB1 (1,4-dimethoxy-2,5-bis [p- {N-phenyl-N- (m-tolyl) amino} styryl] benzene, the following chemical formula (b)) are disclosed. . These materials are reported to emit blue and green light, respectively, and exhibit a low ASE oscillation threshold and a high ASE gain (ratio of ASE emission intensity to excitation intensity).

However, even when these light emitting materials are used, an organic solid-state laser capable of generating a blue laser beam with a sufficiently low ASE oscillation threshold and a high ASE gain cannot be obtained.
JP 2000-156536 A JP 2005-281185 A Japanese Patent Laid-Open No. 2002-275459 Applied Physics Letters 86,0711110-1 (2005)

  An object of the present invention is to provide a light emitting material for an organic solid-state laser and an organic solid-state laser capable of generating a blue laser beam while having a sufficiently low ASE oscillation threshold and a high ASE gain.

In order to achieve the above-mentioned problems, the present inventors have made extensive studies on ASE characteristics under optical excitation using a thin film in which a laser dye is doped in 4,4′-bis (N-carbazol) biphenyl (CBP). As a result, it has been found that the fluorene compound represented by the general formula (1) is used as a laser dye to have a low ASE oscillation threshold, and the present invention has been completed.
That is, the light emitting material for organic solid-state laser of the present invention is characterized by comprising a fluorene compound represented by the general formula (1).
The organic solid-state laser of the present invention is an organic solid-state laser having an anode, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode sequentially on a substrate, wherein the light-emitting layer is represented by the general formula (1) It is characterized by including.

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may be bonded to each other to form a ring, and Q ¹ and Q ² are each independently an aryl group having 6 to 40 carbon atoms which may have a substituent, or 4 to 40 carbon atoms. Represents a heteroaryl group of

The light emitting material for organic solid-state laser of the present invention comprises a fluorene compound represented by the above general formula (1), which is contained in the light emitting layer, and uses a conventional stilbene derivative that oscillates a blue laser. A low ASE oscillation threshold and a high ASE gain.
The organic solid-state laser of the present invention exhibits a lower ASE oscillation threshold and a higher ASE gain than those using a stilbene derivative that oscillates a conventional blue laser.

The light emitting material for organic solid-state laser of the present invention will be described.
The light emitting material for organic solid-state laser of the present invention comprises a fluorene compound represented by the above general formula (1) which is a laser dye.

In the fluorene compound represented by the general formula (1), Q ¹ and Q ² are each independently an aryl group having 6 to 40 carbon atoms or a heteroaryl group having 4 to 40 carbon atoms, which may have a substituent. To express.
Specific examples of the aryl group having 6 to 40 carbon atoms that may have a substituent include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-anthryl group, a 9-anthryl group, and 2-fluorenyl. Group, phenanthryl group, pyrenyl group, chrysenyl group, perylenyl group, picenyl group, or these aryl groups, halogen atom, linear, branched or cyclic alkyl group, linear, branched or cyclic alkoxy group, Examples include those in which an amino group, aryl group, or heteroaryl group is substituted.
Specific examples of the heteroaryl group having 4 to 40 carbon atoms which may have a substituent include a 4-quinolyl group, a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group, and 3-furyl. Group, 2-furyl group, 3-thienyl group, 2-thienyl group, 2,2′-bithiophen-5-yl group, 2-oxazolyl group, 2-thiazolyl group, 2-benzoxazolyl group, 2-benzothiazolyl Group, 2-benzimidazolyl group, or these heteroaryl groups, halogen atom, linear, branched or cyclic alkyl group, linear, branched or cyclic alkoxy group, amino group, aryl group, heteroaryl group Are substituted.

Examples of the halogen atom include a fluorine, chlorine, bromine or iodine atom.
Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group. Tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, trichloromethyl group, trifluoromethyl group, cyclopropyl group, cyclohexyl group, 1,3-cyclohexadienyl group, 2-cyclopentene- A 1-yl group etc. can be illustrated.
Examples of the alkoxy group include linear, branched or cyclic alkoxy groups having 1 to 18 carbon atoms, specifically, methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, sec- Examples include butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, stearyloxy group, trifluoromethoxy group and the like.
Examples of the amino group include a dimethylamino group, a diethylamino group, a dibutylamino group, a diphenylamino group, a (naphthyl) phenylamino group, a di (p-tolyl) amino group, and a carbazoyl group.
As the aryl group, phenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n-propylphenyl Group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-tert-butylphenyl group, 4-cyclopentylphenyl group, 4-cyclohexylphenyl group, 2,4-dimethylphenyl group, 3,5-dimethylphenyl Group, 3,4-dimethylphenyl group, biphenyl group, 1-naphthyl group, 2-naphthyl group, 9-phenanthryl group, anthryl group, 9,9-dialkyl-fluoren-2-yl group and the like.
As the heteroaryl group, 4-quinolyl group, 4-pyridyl group, 3-pyridyl group, 2-pyridyl group, 3-furyl group, 2-furyl group, 3-thienyl group, 2-thienyl group, 2-oxazolyl group 2-thiazolyl group, 2-benzoxazolyl group, 2-benzothiazolyl group, 2-benzimidazolyl group and the like.

In the general formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms. R ¹ and R ² may be bonded to each other to form a ring.
Examples of the halogen atom include a fluorine, chlorine, bromine or iodine atom.
Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms, and specific examples include the aforementioned alkyl groups such as a methyl group, an ethyl group, a propyl group, and an isopropyl group. can do.
As an aryl group, it is a C6-C40 aryl group which may have a substituent, and specifically, a phenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n-propylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-tert-butylphenyl group, 4- Cyclopentylphenyl group, 4-cyclohexylphenyl group, 2,4-dimethylphenyl group, 3,5-dimethylphenyl group, 3,4-dimethylphenyl group, 1-biphenyl group, 1-naphthyl group, 2-naphthyl group, 9 Examples of the aryl group include a phenanthryl group and a 9,9-dialkyl-fluoren-2-yl group.
R ¹ and R ² are bonded to each other to form 1,4-tetramethylene group, 1,5-pentamethylene group, 1,6-hexamethylene group, 1,1′-biphenyl-2,2′-diyl. It may be a divalent substituent such as a group.

In the general formula (1), preferred specific examples are fluorene compounds in which Q ¹ and Q ² are each independently a group represented by the following general formula (2).

(In the formula, X ¹ and X ² are any group selected from monovalent or divalent benzene, biphenyl, naphthalene, anthracene, terphenyl or fluorene, and p is an integer of 0 to 2.)

A more preferred specific example is a fluorene compound represented by the following general formula (3), wherein X ² in the general formula (2) is a substituent having an amino group.

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may be bonded to each other to form a ring, and Ar ^{1 to} Ar ⁴ are each independently a substituted or unsubstituted aryl group having 6 to 40 carbon atoms or heteroaryl having 4 to 40 carbon atoms. Represents a group, and Ar ¹ and Ar ² , or Ar ³ and Ar ⁴ may form a nitrogen-containing heterocyclic ring together with the nitrogen atom to which M is bonded, and M may have a substituent and has 6 to 40 carbon atoms. Represents an arylene group of

Examples of the substituted or unsubstituted aryl group having 6 to 40 carbon atoms include phenyl group, 1-naphthyl group, 2-naphthyl group, 2-anthryl group, 9-anthryl group, 2-fluorenyl group, phenanthryl group, pyrenyl group, Chrysenyl group, perylenyl group, picenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n-propyl Phenyl group, 4-isopropylphenyl group, 2-isopropylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-sec-butylphenyl group, 2-sec-butylphenyl group, 4-tert-butyl Phenyl group, 3-tert-butylphenyl group, 2-tert-butylphenyl group, 4-n-pentyl Enyl group, 4-isopentylphenyl group, 2-neopentylphenyl group, 4-tert-pentylphenyl group, 4-n-hexylphenyl group, 4- (2'-ethylbutyl) phenyl group, 4-n-heptylphenyl Group, 4-n-octylphenyl group, 4- (2'-ethylhexyl) phenyl group, 4-tert-octylphenyl group, 4-n-decylphenyl group, 4-n-dodecylphenyl group, 4-n-tetra Decylphenyl group, 4-cyclopentylphenyl group, 4-cyclohexylphenyl group, 4- (4'-methylcyclohexyl) phenyl group, 4- (4'-tert-butylcyclohexyl) phenyl group, 3-cyclohexylphenyl group, 2- Cyclohexylphenyl group, 4-ethyl-1-naphthyl group, 6-n-butyl-2-naphthyl group, 2,4 Dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2,4-diethylphenyl group, 2,3,5- Trimethylphenyl group, 2,3,6-trimethylphenyl group, 3,4,5-trimethylphenyl group, 2,6-diethylphenyl group, 2,5-diisopropylphenyl group, 2,6-diisobutylphenyl group, 2, 4-di-tert-butylphenyl group, 2,5-di-tert-butylphenyl group, 4,6-di-tert-butyl-2-methylphenyl group, 5-tert-butyl-2-methylphenyl group, 4-tert-butyl-2,6-dimethylphenyl group, 9-methyl-2-fluorenyl group, 9-ethyl-2-fluorenyl group, 9-n-hexyl- -Fluorenyl group, 9,9-dimethyl-2-fluorenyl group, 9,9-diethyl-2-fluorenyl group, 9,9-di-n-propyl-2-fluorenyl group, 4-methoxyphenyl group, 3-methoxy Phenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 3-ethoxyphenyl group, 2-ethoxyphenyl group, 4-n-propoxyphenyl group, 3-n-propoxyphenyl group, 4-isopropoxyphenyl group, 2-isopropoxyphenyl group, 4-n-butoxyphenyl group, 4-isobutoxyphenyl group, 2-sec-butoxyphenyl group, 4-n-pentyloxyphenyl group, 4-isopentyloxyphenyl group, 2-iso Pentyloxyphenyl group, 4-neopentyloxyphenyl group, 2-neopentyloxyphenyl group, 4- n-hexyloxyphenyl group, 2- (2′-ethylbutyl) oxyphenyl group, 4-n-octyloxyphenyl group, 4-n-decyloxyphenyl group, 4-n-dodecyloxyphenyl group, 4-n- Tetradecyloxyphenyl group, 4-cyclohexyloxyphenyl group, 2-cyclohexyloxyphenyl group, 2-methoxy-1-naphthyl group, 4-methoxy-1-naphthyl group, 4-n-butoxy-1-naphthyl group, 5 -Ethoxy-1-naphthyl group, 6-methoxy-2-naphthyl group, 6-ethoxy-2-naphthyl group, 6-n-butoxy-2-naphthyl group, 6-n-hexyloxy-2-naphthyl group, 7 -Methoxy-2-naphthyl group, 7-n-butoxy-2-naphthyl group, 2-methyl-4-methoxyphenyl group, 2-methyl-5-methoxyphenyl Enyl group, 3-methyl-4-methoxyphenyl group, 3-methyl-5-methoxyphenyl group, 3-ethyl-5-methoxyphenyl group, 2-methoxy-4-methylphenyl group, 3-methoxy-4-methyl Phenyl group, 2,4-dimethoxyphenyl group, 2,5-dimethoxyphenyl group, 2,6-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3,5-diethoxyphenyl Group, 3,5-di-n-butoxyphenyl group, 2-methoxy-4-ethoxyphenyl group, 2-methoxy-6-ethoxyphenyl group, 3,4,5-trimethoxyphenyl group, 4-biphenylyl group, 3-biphenylyl group, 2-biphenylyl group, 4- (4′-methylphenyl) phenyl group, 4- (3′-methylphenyl) phenyl group, 4- (4′- Toxiphenyl) phenyl group, 4- (4′-n-butoxyphenyl) phenyl group, 2- (2′-methoxyphenyl) phenyl group, 4- (4′-chlorophenyl) phenyl group, 3-methyl-4-phenyl Phenyl group, 3-methoxy-4-phenylphenyl group, terphenyl group, 3,5-diphenylphenyl group, 10-phenylanthryl group, 10- (3,5-diphenylphenyl) -9-anthryl group, 9- Phenyl-2-fluorenyl group, 4-fluorophenyl group, 3-fluorophenyl group, 2-fluorophenyl group, 4-chlorophenyl group, 3-chlorophenyl group, 2-chlorophenyl group, 4-bromophenyl group, 2-bromophenyl Group, 4-chloro-1-naphthyl group, 4-chloro-2-naphthyl group, 6-bromo-2-naphthyl group, 2,3- Fluorophenyl group, 2,4-difluorophenyl group, 2,5-difluorophenyl group, 2,6-difluorophenyl group, 3,4-difluorophenyl group, 3,5-difluorophenyl group, 2,3-dichlorophenyl group 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 2,5-dibromophenyl group, 2,4,6-trichlorophenyl group, 2,4 -Dichloro-1-naphthyl group, 1,6-dichloro-2-naphthyl group, 2-fluoro-4-methylphenyl group, 2-fluoro-5-methylphenyl group, 3-fluoro-2-methylphenyl group, 3 -Fluoro-4-methylphenyl group, 2-methyl-4-fluorophenyl group, 2-methyl-5-fluorophenyl group, 3-methyl -4-fluorophenyl group, 2-chloro-4-methylphenyl group, 2-chloro-5-methylphenyl group, 2-chloro-6-methylphenyl group, 2-methyl-3-chlorophenyl group, 2-methyl- 4-chlorophenyl group, 3-chloro-4-methylphenyl group, 3-methyl-4-chlorophenyl group, 2-chloro-4,6-dimethylphenyl group, 2-methoxy-4-fluorophenyl group, 2-fluoro- 4-methoxyphenyl group, 2-fluoro-4-ethoxyphenyl group, 2-fluoro-6-methoxyphenyl group, 3-fluoro-4-ethoxyphenyl group, 3-chloro-4-methoxyphenyl group, 2-methoxy- 5-chlorophenyl group, 3-methoxy-6-chlorophenyl group, 5-chloro-2,4-dimethoxyphenyl group and the like can be mentioned. , But it is not limited thereto.
The substituted or unsubstituted heteroaryl group having 4 to 40 carbon atoms is an aromatic group containing at least one heteroatom among an oxygen atom, a nitrogen atom and a sulfur atom, such as a 4-quinolyl group, 4- Pyridyl group, 3-pyridyl group, 2-pyridyl group, 3-furyl group, 2-furyl group, 3-thienyl group, 2-thienyl group, 2-oxazolyl group, 2-thiazolyl group, 2-benzoxazolyl group , 2-benzothiazolyl group, 2-benzimidazolyl group and the like, but are not limited thereto.

In the fluorene compound represented by the general formula (3), Ar ¹ and Ar ² , or Ar ³ and Ar ⁴ may form a nitrogen-containing heterocycle together with the nitrogen atom to which the fluorene compound is bonded. N-carbazolyl group, -N-phenoxazinyl group, or -N-phenothiazinyl group may be formed.
In the nitrogen-containing heterocycle, examples of the substituent include a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group, and an aryl group having 6 to 10 carbon atoms, and may be mono-substituted or poly-substituted. Among these, preferably, an unsubstituted halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group, or an —N-carbazolyl group monosubstituted or polysubstituted with an aryl group having 6 to 10 carbon atoms, -N-phenoxazinyl group or -N-phenothiazinyl group, more preferably unsubstituted -N-carbazolyl group, -N-phenoxazinyl group, or -N-phenothazinyl group. It is.

  Specific examples of the substituted -N-carbazolyl group, -N-phenoxazinyl group, or -N-phenothiazinyl group include, for example, 2-methyl-N-carbazolyl group, 3-methyl-N-carbazolyl group Group, 4-methyl-N-carbazolyl group, 3-n-butyl-N-carbazolyl group, 3-n-hexyl-N-carbazolyl group, 3-n-octyl-N-carbazolyl group, 3-n-decyl- N-carbazolyl group, 3,6-dimethyl-N-carbazolyl group, 2-methoxy-N-carbazolyl group, 3-methoxy-N-carbazolyl group, 3-ethoxy-N-carbazolyl group, 3-isopropoxy-N- Carbazolyl group, 3-n-butoxy-N-carbazolyl group, 3-n-octyloxy-N-carbazolyl group, 3-n-decyl Oxy-N-carbazolyl group, 3-phenyl-N-carbazolyl group, 3- (4′-methylphenyl) -N-carbazolyl group, 3- (4′-tert-butylphenyl) -N-carbazolyl group, 3- A chloro-N-carbazolyl group, a 2-methyl-N-phenothiazinyl group, etc. can be mentioned.

In the fluorene compound represented by the general formula (3), M represents an arylene group having 6 to 40 carbon atoms which may have a substituent. As the arylene group, an optionally substituted phenylene group, 1,4-naphthalene-diyl group, 4,4′-biphenyl-diyl group, 4,4′-terphenyl-diyl group, 2,6- Naphthalene-diyl group, 9,10-anthracene-diyl group, 2,7-9,9′-dimethylfluorene-diyl group, 2,7-9,9′-diphenylfluorene-diyl group, or these groups are Examples include groups connected by a bond. Examples of the substituent include the substituents exemplified in R ¹ and R ² above.

  A particularly preferred specific example is a fluorene compound represented by the following general formula (4).

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may combine with each other to form a ring, and M independently represents an arylene group having 6 to 40 carbon atoms which may have a substituent.

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited to these compounds.

  The fluorene compound represented by the general formula (1) is, for example, a Suzuki-Miyaura reaction using (hetero) aryl halide or (hetero) arylsulfonate and (hetero) arylboronic acid, or (hetero) aryl halide and ( It can be produced by a known method such as a Buchwald-Hartwig reaction using a hetero) arylamine.

Next, the organic solid-state laser of the present invention will be described.
The organic solid-state laser of the present invention has an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode sequentially on a substrate.

  The light emitting layer in the organic solid-state laser of the present invention contains the fluorene compound. The light emitting layer preferably contains a host material such as a carbazole derivative. Examples of the carbazole derivative serving as the host material include CBP (4,4′-bis (N-carbazol) biphenyl), mCP (m-bis (N-carbazole) benzene), or JP-A-2005-239703, The compounds described in JP-A-2006-69964 can be exemplified, but other materials may be used.

  There is no restriction | limiting in particular in the film thickness of a light emitting layer, Although it can select suitably, Usually, it is preferable to set it as the range of 5-500 nm.

In the present invention, the anode is preferably formed of an anode electrode material such as a metal having a high work function (4 eV or more) or an alloy thereof, a conductive compound, and a mixture thereof. Specific examples of the electrode material for the anode include metals such as Au, and conductive materials such as CuI, ITO (indium tin oxide), SnO ₂ , and ZnO.
The thickness of the anode is usually 10 nm to 1 μm, preferably 50 to 200 nm.
As a method for forming the anode, a conventionally known method such as vapor deposition or sputtering can be used.

In the present invention, the cathode has a function of injecting electrons into the light emitting layer or the electron transport layer. The cathode is preferably formed from a cathode electrode material such as a metal having a low work function (4 eV or less) or an alloy thereof, a conductive compound, and a mixture thereof. Specific examples of the electrode material for the cathode include Na, Na · K alloy, Mg, Li, Mg / Cu mixture, Mg · Ag alloy, Al·Li alloy, Al / Al ₂ O ₃ mixture, In, rare earth metal, etc. Can be mentioned.
The thickness of the cathode is usually 10 nm to 1 μm, preferably 50 to 200 nm.
As a method for forming the cathode, a conventionally known method such as vapor deposition or sputtering can be used.

  Examples of hole transport materials used in the hole transport layer include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, aryl Amine derivatives, amino-substituted chalcone derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styryl amine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, Examples thereof include conductive polymer oligomers such as polyvinylcarbazole derivatives, aniline copolymers, thiophene oligomers, and polythiophene.

  Examples of the electron transport material used for the electron transport layer include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthalene perylene, carbodiimides, fluorenylidenemethane derivatives, anthra Examples thereof include quinodimethane and anthrone derivatives, oxadiazole derivatives and the like. A series of electron transport compounds described in JP-A-59-194393 can also be used as an electron transport material. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum. , Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc and the like, and the central metals of these metal complexes are In, Mg, Cu, Ca Metal complexes replaced with Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having a terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport material. Distyrylpyrazine derivatives can also be used as an electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as an electron transport material. The electron transport layer made of the above electron transport material has an electron donating donor made of an alkali metal or alkaline earth metal, and a compound such as an alkali metal or alkaline earth metal fluoride, chloride, or iodide. 30 mol% doping is preferred.

  The thickness of the hole transport layer is preferably 100 to 2000 nm, and more preferably 200 to 500 nm. The thickness of the electron transport layer is preferably 100 to 2000 nm, and more preferably 200 to 500 nm. If the thickness of the hole transport layer and the thickness of the electron transport layer are within such ranges, laser light can be obtained by totally reflecting light emitted from the light emitting layer at the contact surface between the hole transport layer and the light emitting layer. .

  In the organic solid-state laser of the present invention, it is preferable that a resonator is provided on one surface of the anode in order to obtain laser light amplified more efficiently.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
In the evaluation of the light emitting material for organic solid-state laser, a method based on photoexcitation was used. A light emitting material for an organic solid-state laser can cause laser oscillation not only by current excitation but also by light excitation. That is, by entering the pumping laser light from the transparent substrate side or the cathode side, the light is amplified in the light emitting layer, and the laser light can be taken out from the end face.

Example 1
The compound 3 was used as a laser dye to form a film of 100 nm on a glass substrate by a co-evaporation method at a concentration of 6 wt% in a CBP host. The emission spectrum and ASE characteristics were measured using a nitrogen gas laser (337 nm, 500 ps, 20 Hz) as an excitation light source in a nitrogen atmosphere. FIG. 1 shows the excitation light intensity dependence of the emission intensity of 6% -compound 3: CBP co-deposited thin film and the molecular structure of the emission spectrum. As the excitation light intensity increased, the spectrum narrowed and the emission intensity increased rapidly. The ASE oscillation wavelength and threshold were λ = 451 nm and Eth = 0.18 ± 0.05 μJ / cm ² . . This ASE oscillation threshold is the lowest value reported so far as an ASE oscillation threshold in a low molecular weight organic solid thin film. This is because 6% -compound 3: CBP co-deposited thin film has a very high radiation rate constant of kr = 1.29 (± 0.1) × 10 ⁹ s ⁻¹ , and the stimulated emission cross section is This is because the oscillation wavelength is as large as σ = 3.2 × 10 ⁻¹⁶ cm ² . Furthermore, as a result of the measurement of net gain and loss factor in the co-deposited film are each ^{g = 20 ± 3cm -1, α} = 5.8cm -1, forming an excellent waveguide and the thin film has high gain I found out that

Comparative Example 1
The same experiment as in Example 1 was performed using BSBCz as a laser dye. As a result, the ASE oscillation threshold was 0.32 μJ / cm ² .

Comparative Example 2
The same experiment as in Example 1 was performed using Compound A as a laser dye. As a result, the ASE oscillation threshold was 1.5 ± 0.1 μJ / cm ² .

Example 2
When compound 3 was replaced with compound 16 and performed according to Example 1, the ASE oscillation wavelength and threshold were λ = 420 nm and Eth = 0.14 ± 0.05 μJ / cm ² .

6% -Compound 3: Excitation light intensity dependence of emission intensity of CBP co-deposited thin film and molecular structure of emission spectrum.

Claims (6)

A light-emitting material for an organic solid-state laser, comprising a fluorene compound represented by the general formula (1).

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may be bonded to each other to form a ring, and Q ¹ and Q ² are each independently an aryl group having 6 to 40 carbon atoms which may have a substituent, or 4 to 40 carbon atoms. Represents a heteroaryl group of ^{2. The} light emitting material for organic solid laser according to claim ¹ , wherein in the general formula (1), Q ¹ and Q ² are each independently a group represented by the following general formula (2).

(Wherein X ¹ and X ² are any group selected from monovalent or divalent benzene, biphenyl, naphthalene, anthracene, terphenyl or fluorene, and p is an integer of 0 to 2). The organic solid according to claim 2, wherein the compound represented by the general formula (1) is a fluorene compound represented by the following general formula (3), wherein X ² is a substituent having an amino group. Light emitting material for laser.

(Wherein R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may be bonded to each other to form a ring, and Ar ^{1 to} Ar ⁴ are each independently a substituted or unsubstituted aryl group having 6 to 40 carbon atoms or heteroaryl having 4 to 40 carbon atoms. Represents a group, and Ar ¹ and Ar ² , or Ar ³ and Ar ⁴ may form a nitrogen-containing heterocyclic ring together with the nitrogen atom to which M is bonded, and M may have a substituent and has 6 to 40 carbon atoms. Represents an arylene group of The fluorene compound represented by the general formula (1) is a fluorene compound represented by the following general formula (4).

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 40 carbon atoms, R ¹ and R ² may combine with each other to form a ring, and M independently represents an arylene group having 6 to 40 carbon atoms which may have a substituent. R ¹ and R ² are each independently a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, substituted or unsubstituted phenyl group, naphthyl group, biphenylyl group, terphenyl group, anthryl group or fluorenyl. The light-emitting material for an organic solid-state laser according to any one of claims 1 to 4, wherein the light-emitting material is a substituent selected from a group. In an organic solid-state laser having an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode sequentially on the substrate,
An organic solid-state laser, wherein the light-emitting layer includes the organic solid-state laser light-emitting material according to any one of claims 1 to 5.

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