WO2024003969A1

WO2024003969A1 - Organic solid-state laser, compound and use thereof

Info

Publication number: WO2024003969A1
Application number: PCT/JP2022/025453
Authority: WO
Inventors: Virginie Simone Francoise PLACIDE; Anthony D'aleo; Jean Charles Maurice Ribierre; Jeong-Weon Wu
Original assignee: Ewha Womans University; Koala Technology Inc
Current assignee: Ewha Womans University; Koala Technology Inc
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2024-01-04
Anticipated expiration: 2024-12-27

Abstract

A compound represented by Formula (1) has excellent lasing properties. R1 and R2 represent an alkyl group; Het1 and Het2 are represented by Formulae (2) to (4); n1 and n2 are 1 to 5; and G1 and G2 represent H or a substituent.

Description

ORGANIC SOLID-STATE LASER, COMPOUND AND USE THEREOF

The present invention relates to an organic solid-state laser, a novel compound and use of the compound as an emitter in an organic solid-state laser.

Research for developing an organic solid-state laser having a low laser oscillation threshold has been actively conducted. In order to realize such an organic solid-state laser, it is necessary to develop organic compounds having excellent lasing properties. For this reason, various organic compounds have been synthesized and their lasing properties have been investigated. Non-Patent Document 1 reports that bisstilbene derivatives such as BSBCz exhibit a low ASE threshold and they are excellent organic laser materials. However, the number of useful organic laser materials is still small.

Non-patent Literature 1: Appl. Phys. Lett. 2005, 86, 071110

An object of the present invention is to provide a new organic laser material and an organic solid-state laser using the material.

As a result of earnest investigations, the inventors have found that a group of compounds with a particular structure have excellent lasing properties. Thus, the inventors have provided the following invention:
[1] An organic solid-state laser containing a compound represented by the following formula (1):
wherein:
R¹ and R² each independently represent a substituted or unsubstituted alkyl group;
Het¹ and Het² are each independently represented by one of the following formulae (2) to (4):
wherein X¹ to X⁵ each independently represent O or S;
R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group;
R³ and R⁴ may be taken together to form a ring;
m¹ and m² each independently represent 0 or 1;
the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other;
each * represents a bonding site;
n1 and n2 are each independently an integer of 1 to 5, and
G¹ and G² each independently represent a hydrogen atom or a substituent;
provided that the compound is free of recurring units.
[2] The organic solid-state laser according to [1], wherein R¹ and R² are the same.
[3] The organic solid-state laser according to [1] or [2], wherein Het¹ and Het² are the same, and G¹ and G² are the same.
[4] The organic solid-state laser according to any one of [1] to [3], wherein the compound has a symmetric structure.
[5] The organic solid-state laser according to any one of [1] to [4], wherein R¹ and R² are each independently a substituted or unsubstituted branched alkyl group.
[6] The organic solid-state laser according to [5], wherein R¹ and R² are each independently a group represented by
wherein R⁹ and R¹⁰ each independently represent a substituted or unsubstituted alkyl group; and * represents a bonding site.
[7] The organic solid-state laser according to any one of [1] to [6], wherein Het¹ and Het² are each independently represented by the formula (2).
[8] The organic solid-state laser according to any one of [1] to [6], wherein Het¹ and Het² are each independently represented by the formula (3).
[9] The organic solid-state laser according to [8], wherein m1 is 0.
[10] The organic solid-state laser according to [8], wherein m1 is 1.
[11] The organic solid-state laser according to any one of [1] to [6], wherein Het¹ and Het² are each independently represented by the formula (4).
[12] The organic solid-state laser according to [11], wherein m2 is 0.
[13] The organic solid-state laser according to [11], wherein m2 is 1.
[14] The organic solid-state laser according to any one of [1] to [13], wherein G¹ and G² are each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group.
[15] The organic solid-state laser according to [14], wherein G¹ and G² are each independently an aryl group substituted by a disubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkylthio group.
[16] The organic solid-state laser according to [14], wherein G¹ and G² are each independently an alkynyl group substituted by a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
[17] The organic solid-state laser according to any one of [1] to [16], wherein X¹, X² and X⁴ are O.
[18] The organic solid-state laser according to any one of [1] to [16], wherein X¹, X² and X⁴ are S.
[19] A compound represented by the following formula (1):
wherein:
R¹ and R² each independently represent a substituted or unsubstituted alkyl group;
Het¹ and Het² are each independently represented by one of the following formulae (2) to (4):
wherein X¹ to X⁵ each independently represent O or S;
R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group;
R³ and R⁴ may be taken together to form a ring;
m1 and m2 each independently represent 0 or 1;
the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other;
each * represents a bonding site;
n1 and n2 are each independently an integer of 1 to 5, and
G¹ and G² each independently represent a substituent;
provided that the compound is free of recurring units, and cyano groups.
[20] Use of the compound of [19] as an emitter in an organic solid-state laser.

The compounds represented by the formula (1) have excellent lasing properties. An organic solid-state laser containing a compound of the formula (1) exhibits low laser oscillation threshold.

Detailed Description of the Invention

The contents of the invention will be described in detail below. The elements of the invention may be described below with reference to representative embodiments and specific examples of the invention, but the invention is not limited to the embodiments and the examples. In the description, a numerical range expressed with reference to an upper limit and/or a lower limit means a range that includes the upper limit and/or the lower limit. The room temperature means 25℃.

Definition
The hydrogen atoms that are present in the compounds used in the invention are not particularly limited in isotope species, and for example, all the hydrogen atoms in the molecule may be ¹H, and all or a part of them may be ²H (deuterium (D)).
The alkyl group referred in the present application may be linear, branched or cyclic, and a linear or branched alkyl group is preferred. Unless otherwise stated, the alkyl group preferably has from 1 to 40 carbon atoms, more preferably from 1 to 30 carbon atoms, further preferably from 1 to 20 carbon atoms, still further preferably from 1 to 12 carbon atoms (e.g., a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group and an n-dodecyl group). Examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a bicylo[2.1.1]hexyl group and a bicyclo[2.2.1]heptyl group. The alkyl group may be substituted. Examples of the substituent in this case include an alkoxy group, an aryl group, an aryloxy group, an acyl group, a hydroxyl group, a halogen atom, a nitro group, a diarylamino group (including a 9-carbazolyl group) and a cyano group, and preferred are an alkoxy group, an aryl group and an aryloxy group.
The aryl group referred in the present application may have a structure containing only one aromatic ring or a structure containing two or more aromatic rings condensed with each other. The aryl group preferably has from 6 to 22 ring skeleton-forming carbon atoms, more preferably from 6 to 18 ring skeleton-forming carbon atoms, further preferably from 6 to 14 ring skeleton-forming carbon atoms, and still further preferably from 6 to 10 ring skeleton-forming carbon atoms. Examples of the aryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthranyl group, a 2-anthranyl group, a 9-anthranyl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, a 9-phenanthryl group, a 1-naphthacenyl group, a 2-naphthacenyl group, a 1-pyrenyl group and a 2-pyrenyl group. The aryl group may be substituted. Examples of the substituent in this case include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, a hydroxyl group, a halogen atom, a nitro group, a diarylamino group (including a 9-carbazolyl group) and a cyano group, and preferred are an alkyl group, an alkoxy group, an aryl group, and an aryloxy group.
The heteroaryl group referred in the present application may have a structure containing only one heteroaromatic ring or a structure containing two or more heteroaromatic rings condensed with each other. The heteroaryl group may contain at least one heteroaromatic ring and at least one aromatic ring. The heteroaryl group preferably has from 5 to 22 ring skeleton-forming atoms, more preferably from 5 to 18 ring skeleton-forming atoms, further preferably from 5 to 14 ring skeleton-forming atoms, and still further preferably from 5 to 10 ring skeleton-forming atoms. Examples of the heteroaryl group include a 2-thienyl group, a 3-thienyl group, a 2-furyl group, a 3-furyl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a 2-pyrazinyl group, a 2-quinolyl group, a 3-quinolyl group, a 4-quinolyl group, a 1-isoquinolyl group and a 3-isoquinolyl group. Other examples of the heteroaryl group include a benzofuryl group, a pyrrolyl group, an indolyl group, an isoindolyl group, an azaindolyl group, a benzothienyl group, a pyridyl group, a quinolinyl group, an isoquinolyl group, an imidazolyl group, a benzimidazolyl group, a pyrazolyl group, an oxazolyl group, an isoxazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, an isothiazolyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a cinnolinyl group, a phthalazinyl group and a quinazolinyl group. The heteroaryl group may be substituted. Examples of the substituent in this case include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a hydroxyl group, a halogen atom, a nitro group, a diarylamino group (including a 9-carbazolyl group) and a cyano group, and preferred are an alkyl group, an alkoxy group, an aryl group, and an aryloxy group.
For the alkyl moiety of the alkoxy group and the dialkylamino group referred in the present application, reference may be made to the description for the alkyl group.
For the aryl moiety of the aryloxy group and the diarylamino group referred in the present application, reference may be made to the description for the aryl group.
The halogen atom referred in the present application is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

Compound represented by the formula (1)
The compound of the invention has a structure represented by the following formula (1):

R¹ and R² in the formula (1) each independently represent a substituted or unsubstituted alkyl group. The alkyl group may be linear, branched or cyclic. preferably, R¹ and R² are a substituted or unsubstituted branched alkyl group. In some embodiments, R¹ and R² are a substituted or unsubstituted alkyl group having from 1 to 40 carbon atoms, more preferably from 2 to 30 carbon atoms, further preferably from 5 to 25 carbon atoms, and for example 13 to 25. The substituent on the alkyl group may be, for example, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a halogen atom. R¹ and R² may be an unsubstituted alkyl group.
R¹ and R² in the formula (1) may be a group represented by the following formula:
In the formula, R⁹ and R¹⁰ each independently represent a substituted or unsubstituted alkyl group, and * represents a bonding site. In some embodiments, R⁹ and R¹⁰ are a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, more preferably from 3 to 18 carbon atoms, and further preferably from 5 to 15 carbon atoms. R⁹ and R¹⁰ may be the same or different from each other. In some embodiments, R⁹ and R¹⁰ are different, and the difference in the number of carbon atoms of the alkyl group between R⁹ and R¹⁰ is from 1 to 5. For the substituent on the alkyl group in R⁹ and R¹⁰, reference may be made to the description for the substituent on the alkyl group in R¹ and R². In some embodiments, R⁹ and R¹⁰ are an unsubstituted alkyl group.
R¹ and R² in the formula (1) may be the same or different from each other. Preferably R¹ and R² are the same.
Het¹ and Het² in the formula (1) are each independently represented by one of the following formulae (2) to (4):
In the formulae (2) to (4), X¹ to X⁵ each independently represent O or S. X¹ to X⁵ may be the same or different from each other. Preferably X² and X⁴, X³ and X⁵ are the same, respectively. In some embodiments, X¹, X² and X⁴ are O. In some embodiments, X¹, X² and X⁴ are S.
In the formulae (2) to (4), R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group, and each * represents a bonding site. For the alkyl group in R³ to R⁸, reference may be made to the above definition for the alkyl group. For the substituent on the alkyl group in R³ to R⁸, reference may be made to the description for the substituent on the alkyl group in R¹ and R². R³ to R⁸ may be the same or different from each other. In some embodiments, R³ to R⁸ are a hydrogen atom.
In the formula (2), R³ and R⁴ may be taken together to form a ring. The formed ring may have from 4 to 10 ring skeleton-forming atoms, more preferably from 5 to 8 ring skeleton-forming atoms, further preferably from 5 to 7 ring skeleton-forming atoms. The formed ring may be an aromatic ring or an aliphatic ring. The formed ring may form a polycyclic condensed structure together with another ring. Examples of the ring include a 4,5-dihydrothiophene ring, a dioxane ring, a dithiane ring, a cyclopentane ring, a cyclohexane ring and a cycloheptane ring, a benzene ring, a naphthalene ring and a pyridine ring.The hydrogen atom of these ring may be substituted by a substituent.
In the formulae (3) and (4), m1 and m2 each independently represent 0 or 1. When m1 and m2 are 0, two 5-membered rings in the formulae (3) and (4) share one side to form a condensed ring having 8 ring members. When m1 and m2 are 1, the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other. The cyclic structure formed by the dashed lines and the double bond in a parentheses and the double bond on the left outside of the parentheses have from 4 to 10 ring skeleton-forming atoms, more preferably from 5 to 8 ring skeleton-forming atoms, further preferably from 5 to 7 ring skeleton-forming atoms. The cyclic structure may be an aromatic ring or an aliphatic ring. The cyclic structure may form a polycyclic condensed structure together with another ring. Examples of the cyclic structure include cyclopentadiene ring, cyclohexadiene ring, furan ring, thiophene ring, pyrrole ring, silole ring, cyclopentadienone ring, benzene ring, pyridine ring, pyrazine ring, condensed ring which two or more of these ring structures condensed, benzothiadiazole ring and 1,3-dihydro-benzimidazol-2-one ring. The hydrogen atom of these ring may be substituted by a substituent.
In some embodiments, Het¹ and Het² are represented by formula (2). In some embodiments, Het¹ and Het² are represented by formula (3) and m1 is 0. In some embodiments, Het¹ and Het² are represented by formula (3) and m1 is 1. In some embodiments, Het¹ and Het² are represented by formula (4) and m2 is 0. In some embodiments, Het¹ and Het² are represented by formula (4) and m2 is 1. In some embodiments, Het¹ and Het² contain one or more thiophene rings, more preferably from 1 to 3 thiophene rings, and further preferably 1 or 2 thiophene rings.

Specific examples of the groups represented by the formulae (2) to (4) are shown below. However, the groups represented by the formulae (2) to (4) that can be used in the invention are not limited to the following specific examples.

In the above formulae, R³ to R¹⁹ represent a hydrogen atom or a substituent, and each * represents a bonding site. For specific examples of R³ to R⁸, reference may be made to specific examples of R³ to R⁸ in the above formulae (2) to (4). Preferably, R¹¹, R¹¹', R¹², R¹²' and R¹³ each independently represent a hydrogen atom, a halogen atom, an alkyl halide group having from 1 to 25 carbon atoms, a cyano group, an alkyl group having from 1 to 25 carbon atoms (at least one methylene group may be substituted by an oxygen atom or a sulfur atom), an arylalkyl group having from 7 to 25 carbon atoms or an alkoxy group having from 1 to 25 carbon atoms. Preferably, R¹⁴, R¹⁴', R¹⁶ and R¹⁶' each independently represent a hydrogen atom, an alkyl group having from 1 to 25 carbon atoms (at least one methylene group may be substituted by oxygen or sulfur atoms) or an aryl alkyl group having from 7 to 25 carbon atoms. Preferably, R¹⁵ and R¹⁵' each independently represent a hydrogen atom or an alkyl having from 1 to 25 carbon atoms. R¹⁷ and R¹⁷' each independently represent an alkyl group having from 1 to 25 carbon atoms (at least one methylene group may be substituted by an oxygen atom or a sulfur atom) an arylalkyl group having from 7 to 25 carbon atoms, a phenyl group that may be substituted by an alkyl group having from 1 to 8 carbon atoms or an alkoxy group having from 1 to 8 carbon atoms. Preferably, R¹⁸ and R¹⁸' each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having from 1 to 25 carbon atoms (at least one methylene group may be substituted by an oxygen atom or a sulfur atom), an arylalkyl group having from 7 to 25 carbon atoms or an alkoxy group having from 1 to 25 carbon atoms or an alkynyl group substituted by an alkyl group or an alkylsilyl group. Preferably, R¹⁹ represents an alkyl group having from 1 to 25 carbon atoms (at least one methylene group may be substituted by an oxygen atom or a sulfur atom).
In some embodiments, Het¹ and Het² are selected from the group consisting of H1 to H26. In some embodiments, Het¹ and Het² are selected from the group consisting of H1, H11 and H12.
Het¹ and Het² in the formula (1) may be the same or different from each other. Preferably Het¹ and Het² are the same.
n1 and n2 in the formula (1) are each independently an integer of 1 to 5. Preferably n1 and n2 are an integer of 1 to 4, more preferably an integer of 1 to 3, and further preferably 1 or 2. n1 and n2 may be the same or different from each other. Preferably n1 and n2 are the same.
When n1 is two or more, then two or more instances of Het¹ may be the same or different, preferably the same. When n2 is two or more, then two or more instances of Het² may be the same or different, preferably the same.
G¹ and G² in the formula (1) each independently represent a hydrogen atom or a substituent, more preferably a substituent capable of stabilizing the molecule.
Examples of the substituent for G¹ and G² include a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group. The substituent on these substituents may be, for example, a disubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkylthio group.
In some embodiments, G¹ and G² are an aryl group substituted by a disubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkylthio group. In some embodiments, G¹ and G² are a an alkynyl group substituted by a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
G¹ and G² in formula (1) is also preferably selected from the group consisting of the following S1 to S11.
In the above formulae, Alk represents a substituted or unsubstituted alkyl group, and each * represents a bonding site. The hydrogen atom in each structure may be substituted by a substituent. In some embodiments, G¹ and G² is selected from the group consisting of S1, S5, S7 and S10.
G¹ and G² in the formula (1) may be the same or different from each other. Preferably G¹ and G² are the same. More preferably G¹ and G² are the same, and Het¹ and Het² are the same. Still further preferably the compound represented by the formula (1) has a symmetric structure.
The compounds represented by the formula (1) do not have any recurring units. In the present application, "recurring unit" means a repeating moiety derived from a monomer or monomers which constitutes the polymer structure formed by polymerization reaction of the monomer or monomers.
Specific examples of the compounds represented by the formula (1) are shown below (Compounds 1 to 18). However, the compounds represented by the formula (1) that can be used in the invention are not limited to the following specific examples.

The molecular weight of the compound represented by the formula (1) is preferably 1,500 or less, more preferably 1,200 or less, further preferably 1,000 or less, and still further preferably 800 or less, for example, in the case where an organic layer containing the compound represented by the formula (1) is intended to be formed as a film by a vapor deposition method. The lower limit of the molecular weight is the molecular weight of the smallest compound represented by the formula (1).
The compound represented by the formula (1) may be formed into a film by a coating method irrespective of the molecular weight thereof. The compound that has a relatively large molecular weight may be formed into a film by a coating method.
As an application of the invention, a compound that contains plural structures each represented by the formula (1) in the molecule may be used as a lasing material.
For example, it may be considered that a polymerizable group is introduced in advance to the structure represented by the formula (1), and a polymer obtained by polymerizing the polymerizable group is used as a light-emitting material. Specifically, it may be considered that a monomer that has a polymerizable functional group at any of R¹, R², Het¹, Het², G1 and G² in the formula (1) is prepared, and is homopolymerized or copolymerized with another monomer to prepare a polymer containing repeating units, and the polymer is used as a lasing material. In alternative, it may be considered that the compounds containing a structure represented by the formula (1) are reacted to form a dimer or a trimer, and the dimer or the trimer is used as a light-emitting material.
Examples of the polymer having the repeating unit containing the structure represented by the formula (1) include a polymer containing a structure represented by the following formula (31) or (32).
In the formulae (31) and (32), Q represents a group containing the structure represented by the formula (1), and L¹ and L² each represent a linking group. The linking group preferably has from 0 to 20 carbon atoms, more preferably from 1 to 15 carbon atoms, and further preferably from 2 to 10 carbon atoms. The linking group preferably has a structure represented by -X¹¹-L¹¹-, wherein X¹¹ represents an oxygen atom or a sulfur atom, and preferably an oxygen atom, and L¹¹ represents a linking group, preferably a substituted or unsubstituted alkylene group or a substituted or unsubstituted arylene group, and more preferably a substituted or unsubstituted alkylene group having from 1 to 10 carbon atoms or a substituted or unsubstituted phenylene group.
In the formulae (31) and (32), R¹⁰¹, R¹⁰², R¹⁰³ and R¹⁰⁴ each independently represent a substituent, preferably a substituted or unsubstituted alkyl group having from 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having from 1 to 6 carbon atoms, or a halogen atom, more preferably an unsubstituted alkyl group having from 1 to 3 carbon atoms, an unsubstituted alkoxy group having from 1 to 3 carbon atoms, a fluorine atom or a chlorine atom, and further preferably an unsubstituted alkyl group having from 1 to 3 carbon atoms or an unsubstituted alkoxy group having from 1 to 3 carbon atoms.
The linking group represented by L¹ and L² may be bonded to any of R¹, R², Het¹, Het², G1 and G² of the structure of the formula (1) constituting Q. Two or more of the linking groups may be bonded to one group represented by Q to form a crosslinked structure or a network structure.
Specific examples of the structure of the repeating unit include structures represented by the following formulae (33) to (36).
The polymer having the repeating unit containing the structure represented by any of the formulae (33) to (36) may be synthesized in such a manner that a hydroxyl group is introduced to any of R¹, R², Het¹, Het², G1 and G² of the formula (1), and the hydroxyl group as a linker is reacted with the following compound to introduce a polymerizable group thereto, followed by polymerizing the polymerizable group.
The polymer containing the structure represented by the formula (1) in the molecule may be a polymer containing only a repeating unit having the structure represented by the formula (1), or a polymer further containing a repeating unit having another structure. The repeating unit having the structure represented by the formula (1) contained in the polymer may be only one kind or two or more kinds. Examples of the repeating unit that does not have the structure represented by the formula (1) include a repeating unit derived from a monomer that is used for ordinary copolymerization. Examples of the repeating unit include a repeating unit derived from a monomer having an ethylenic unsaturated bond, such as ethylene and styrene.

Synthesis of Compound represented by Formula (1)
The compounds represented by the formula (1) can be synthesized by known reactions. The reaction conditions may be appropriately determined. For the details of the reactions, reference may be made to Synthesis Examples 1 below.

Organic solid-state laser
The present invention also provides an organic solid-state laser (organic semiconductor laser) containing a compound represented by the formula (1). A compound of the formula (1) is useful as a material used in a light-emitting layer (light amplification layer) of the organic solid-state laser. The light-emitting layer may contain two or more compounds of the formula (1) but preferably contains only one compound of the formula (1). The light-emitting layer may contain a host material. Preferable host material absorbs photo-excitation light for the organic solid-state laser. Another preferable host material has sufficient spectral overlap between its fluorescence spectrum and the absorption spectrum of the compound of the formula (1) contained in the light-emitting layer so that an effective Forster-type energy transfer can take place from the host material to the compound of the formula (1). The concentration of the compound of the formula (1) in the light-emitting layer is preferably at least 0.1 wt%, more preferably at least 1 wt%, still more preferably at least 3 wt%, and preferably at most 50 wt%, more preferably at most 30 wt%, still more preferably at most 10 wt%.
The organic solid-state laser of the present invention has an optical resonator structure. The optical resonator structure may be a one-dimensional resonator structure or a two-dimensional resonator structure. Examples of the latter include a circulator resonator structure, and a whispering gallery type optical resonator structure. A distributed feedback (DFB) structure and a distributed Bragg reflector (DBR) structure are also employable. For DFB, a second order DFB grating structure is preferably employed. A mixed-order DFB grating structure may be also employed. Namely, a mixed structure of DFB grating structures differing in point of the order relative to laser emission wavelength may be preferably employed. Specific examples thereof include an optical resonator structure composed of a second-order Bragg scattering region. For details of preferred optical resonator structures, specific examples to be given hereinunder may be referred to. As the optical resonator structure, the organic solid-state laser may be further provided with an external optical resonator structure. For example, the optical resonator structure may be formed preferably on a glass substrate. The material to constitute the optical resonator structure includes an insulating material such as SiO₂, etc. For example, a grating structure is formed, the depth of the grating is preferably 75 nm or less, and is more preferably selected from a range of 10 to 75 nm. The depth may be, for example, 40 nm or more, or may be less than 40 nm. The light-emitting layer (light amplification layer) containing a compound of the formula (1) can be directly formed on the optical resonator structure.
The organic solid-state laser is preferably encapsulated by a sapphire or other materials to lower the lasing threshold and optimize the heat dissipation under intense optical pumping. An interlayer may be formed between the sapphire lid and the light-emitting layer. For example, amorphous fluorinated polymer such as CYTOP (trademark) is preferably used in the interlayer.

Other advantages and features of the present invention may be better understood with respect to the following examples given for illustrative purposes.

Examples

The invention will be described more specifically with reference to synthesis examples and working examples below. The materials, processes, procedures and the like shown below may be appropriately modified unless they deviate from the substance of the invention. Accordingly, the scope of the invention is not construed as being limited to the specific examples shown below.
The light emission characteristics were evaluated by using a high-performance UV/Vis/NIR spectrophotometer (Lambda 950, produced by PerkinElmer, Co., Ltd.), a fluorescence spectrophotometer (FluoroMax-4, produced by Horiba, Ltd.), an absolute PL quantum yield measurement system (C11347, produced by Hamamatsu Photonics K.K.), a source meter (2400 Series, produced by Keithley Instruments Inc.), a semiconductor parameter analyzer (E5273A, produced by Agilent Technologies, Inc.), an optical power meter (1930C, produced by Newport Corporation), an optical spectrometer (USB2000, produced by Ocean Optics, Inc.), a spectroradiometer (SR-3, produced by Topcon Corporation),

Syntheses
(Synthesis Example 1) Synthesis of Compound 1
The dibromo-diketopyrrolopyrrole (DPP) derivative (A1) (1.0 eq) and the boronic acid derivative (A2) (2.2 eq) were suspended in toluene (12 mL). An aqueous solution of Cs₂CO₃ (2M, 20.0 eq) was added, and the resulting mixture was degassed under nitrogen flux for 20min. Then, Pd(PPh₃)₄ was added and the reaction mixture was stirred at 80°C for 16h, under N₂ atmosphere. At the end of the reaction, H₂O and CH₂Cl₂ were added and the organic layer was washed three times with H₂O, dried over Na₂SO₄, filtered, and evaporated under reduced pressure. The crude was then purified by SiO₂ column chromatography (Eluent: Hexane/CH₂Cl₂) to give the desired compound 1 (92%).
¹H (300 MHz, CDCl₃) δ: 8.96 (d, J= 4.1 Hz, 2H), 7.53 (d, J= 8.8 Hz, 4H), 7.37-7,27 (m, 7H), 7.16-7.14 (m, 4H), 7.13 (m, 3H), 7.10 (t, J= 1.15Hz, 3H), 7.09-7.07 (m, 4H), 7.06 (m, 2H), 4.06 (d, J= 7.6 Hz, 4H), 1.99 (bs, 2H), 1.33-1.21 (m, 46H), 0.83 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.77, 149.70, 148.52, 147.11, 139.66, 136.97, 129.44, 127.96, 126.91, 126.66, 124.99, 123.67, 122.90, 107.97, 37.87, 31.87, 31.83, 29.57, 29.29, 26.39, 22.65, 22.62, 14.11, 14.09

(Synthesis Examples 2 to 18) Synthesis of Compounds 2 to 18
Compounds 2 to 18 were synthesized in the same manner as in Synthesis Example 1.

Compound 2
¹H (300 MHz, CDCl₃) δ: 9.01 (d, J= 4.1 Hz, 2H), 8.43 (d, J = 1.3 HZ, 2H), 8.21 (dt, J= 7.6 Hz, J= 1.1 Hz, 2H), 7.73 (dd, J= 8.6 Hz, J= 1.8 Hz, 2H), 7.66-7.56 (m, 8H), 7.53-7.43 (m, 8H), 7.40 (s, 1H), 7.37-7.34 (m, 2H), 4.13 (d, J=7.6 Hz, 4H), 2.06 (bs, 2H), 1.39-1.20 (m, 46H), 0.81 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.96, 151.18, 141.65, 141.23, 139.83, 137.38, 137.07, 130.14, 128.08, 127.95, 127.18, 126.75, 125.65, 124.67, 124.16, 123.65, 123.26, 120.71, 120.63, 118.14, 110.51, 110.26, 108.03, 46.46, 38.13, 32.03, 31.58, 30.30, 29.96, 29.79, 29.50, 26.63, 26.60, 22.81, 14.24.

Compound 3
¹H (300 MHz, CDCl₃) δ: 8.82 (d, J= 4.1 Hz, 2H), 7.80 (d, J= 8.1 Hz, 4H), 7.71 (d, J= 8.3 Hz, 4H), 7.56 (d, J= 4.1 Hz, 2H), 4.09 (d, J= 7.5 Hz, 4H), 1.99 (bs, 2H), 1.36-1.25 (m, 46H), 0.86 (m, 12H)

Compound 4
¹H (300 MHz, CDCl₃) δ: 8.74 (d, J= 4.2 Hz, 2H), 7.89-7.84 (m, 8H), 7.70-7.67 (dd, J= 8.0 Hz, J= 1.7 Hz, 2H), 7.42-7.37 (m, 6H), 7.23 (d, J= 4.2 Hz, 2H), 7.13 (td, J= 7.5 Hz, J= 1.0 Hz, 6H), 7.01 (d, J= 1.2 Hz, 2H), 6.76 (d, J=7.6 Hz, 4H), 6.72 (d, J= 7.4 Hz, 2H), 3.96 (d, J= 7.3 Hz, 4H), 1.86 (bs, 2H), 1.21-1.18 (m, 48H), 0.83 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ : 161.65, 149.79, 149.57, 149.38, 148.20, 142.65, 141.80, 140.80, 139.62, 136.39, 132.79, 128.62, 128.35, 127.96, 127.89, 126.27, 124.48, 124.07, 121.41, 120.62, 120.22, 120.16, 108.21, 65.97, 31.89, 31.73, 31.14, 31.13, 31.12, 31.11, 29.97, 29.62, 29.48, 29.28, 26.19, 26.18, 26.14, 22.67, 22.60, 14.13, 14.10.

Compound 5
¹H (300 MHz, CDCl₃) δ: 9.01 (d, J= 4.1 Hz, 2H), 8.17 (dt, J= 7.8Hz, 4H), 7.93 (d, J= 6.6 Hz, 4H), 7.68 (d, J= 8.7 Hz, 4H), 7.58 (d, J= 4.1 Hz, 2H), 7.50-7.44 (m, 8H), 7.35-7.30 (m, 4H), 4.12 (d, J= 7.5 Hz, 4H), 2.05 (bs, 2H), 1.39-1.26 (m, 46H), 0.84 (m, 12H)

Compound 6
¹H (300 MHz, CDCl₃) δ: 8.94 (d, J= 4.1 Hz, 2H), 7.68 (d, J= 8.6 Hz, 4H), 7.44-7.39 (m, 6H), 4.05 (d, J= 7.6 Hz, 4H), 3.46 (q, 2H), 1.93 (bs, 2H), 1.34 (m, 20H), 1.21 (m, 34 H), 0.84 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.70, 149.00, 139.76, 137.15, 136.78, 131.44, 131.23, 128.74, 126.29, 124.33, 108.27, 37.92, 31.89, 31.83, 31.36, 30.06, 29.72, 29.58, 29.31, 26.40, 26.36, 23.06, 22.67, 22.63, 14.12, 14.10

Compound 7
¹H (300 MHz, CDCl₃) δ: 8.88 (d, J= 4.1 Hz, 2H), 7.38-7.27 (m, 14H), 7.15-7.11 (m, 10H), 7.10-7.07 (m, 3H), 7.02-6.99 (m, 4H), 4.01 (d, J= 7.7 Hz, 4H), 1.95 (bs, 2H), 1.32-1.22 (m, 48H), 0.84 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.71, 148.78, 147.06, 139.59, 135.73, 132.67, 132.50, 130.18, 129.63, 129.33, 125.46, 124.08, 121.80, 114.67, 108.83, 98.65, 81.91, 37.92, 32.03, 31.92, 31.30, 30.16, 29.82, 29.67, 29.45, 26.32, 26.29, 22.81, 22.77, 14.26, 14.24

Compound 8
¹H (300 MHz, CDCl₃) δ: 8.91 (d, J = 4.1 Hz, 2H), 7.62 (m, 12H), 7.47 (t, J= 7.3 Hz, J = Hz, 4H), 7.41-7.38 (m, 4H), 4.02 (d, J= 7.5 Hz, 4H), 1.97 (bs, 2H), 1.34-1.23 (m, 48H), 0.85 (m, 12H)

Compound 9
¹H (300 MHz, CDCl₃) δ: 9.31 (s, 2H), 7.50 (d, J= 8.7 Hz, 4H), 7.41 (s, 2H), 7.32-7.27 (m, 8H), 7.16-7.13 (m, 8H), 7.10-7.06 (m, 8H), 4.08 (d, J= 7.6 Hz, 4H), 2.02 (bs, 2H), 1.35-1.21 (m, 64H), 0.84 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 147.30, 144.71, 138.96, 130.28, 129.58, 127.74, 126.97, 125.10, 123.75, 123.02, 32.07, 32.05, 31.36, 30.23, 29.84, 29.82, 29.77, 29.71, 29.54, 29.48, 26.39, 22.84, 14.26.

Compound 10
¹H (300 MHz, CDCl₃) δ: 8.96 (d, J= 4.2 Hz, 2H), 7.50 (d, J= 9.0 Hz, 4H), 7.37-7.26 (m, 18H), 7.24 (m, 4H), 4.72 (s, 8H), 4.04 (d, J = 7.6 Hz, 4H), 1.98 (bs, 2H), 1.31-1.20 (m, 48H), 0.82 (m, 12H)

Compound 11
¹H (300 MHz, CDCl₃) δ: 8.95 (d, J = 4.1 Hz, 2H), 7.47 (d, J= 8.8 Hz, 4H), 7.31 (d, J = 8.9 Hz, 2H), 7.10 (d, J = 8.3 Hz, 8H), 6.93-6.84 (m, 12H), 4.05 (d, J = 7.5 Hz, 4H), 3.81 (s, 12H), 1.99 (bs, 2H), 1.33-1.21 (m, 48H), 0.83 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.82, 156.49, 150.18, 149.47, 140.21, 139.61, 137.17, 127.50, 127.15, 126.89, 124.91, 122.96, 119.81, 114.93, 107.88, 55.58, 46.37, 38.01, 31.98, 31.43, 30.18, 29.86, 29.68, 29.40, 26.47, 22.76, 14.22.

Compound 12
¹H (300 MHz, CDCl₃) δ: 8.95 (d, J= 4.2 Hz, 2H), 7.46 (d, J = 8.7 Hz, 4H), 7.31-7.26 (m, 12H), 7.18-7.04 (m, 18H), 4.05 (d, J = 7.5 Hz, 4H), 1.99 (bs, 2H), 1.34-1.21 (m, 64H), 0.88 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.74, 147.95, 147.44, 145.32, 142.96, 139.35, 136.91, 134.58, 129.52, 126.62, 124.89, 123.52, 123.38, 108.46, 46.45, 38.12, 32.07, 32.06, 31.51, 30.25, 29.84, 29.82, 29.76, 29.53, 29.49, 26.56, 22.84, 22.82, 14.27.

Compound 13
¹H (300 MHz, CDCl₃) δ: 8.43 (d, J =4.0 Hz, 2H), 7.60 (d, J= 8.8 Hz, 4H), 7.32-7.27 (m, 8H), 7.15-7.06 (m, 16H), 6.83 (d, J= 4.0 Hz, 2H), 4.15 (d, J = 7.7 Hz, 4H), 1.97 (bs, 2H), 1.32-1.15 (m, 48H), 0.80 (m, 12H)
¹³C NMR (75 MHz, CDCl₃) δ: 161.33, 157.11, 148.65, 147.20, 143.80, 132.81, 129.59, 125.71, 125.22, 123.89, 122.95, 122.64, 108.14, 106.73, 47.09, 38.29, 31.97, 31.89, 31.49, 31.43, 30.24, 29.91, 29.63, 29.42, 26.56, 26.54, 22.80, 22.74, 14.26, 14.21.

Compound 14
¹H (300 MHz, CDCl₃) δ: 8.95 (d, J= 3.96 Hz, 2H), 7.70 (d, J= 7.69 Hz, 4H), 7.61-7.57 (m, 4H), 7.35-7.32 (m, 12H), 4.08 (d, J= Hz, 4H), 2.01 (t, 10H, J= 7.44 Hz), 1.37-1.23 (m, 54H), 1.14-1.06 (m, 22H), 0.87-0.83 (m, 10H), 0.76 (t, J= 6.99 Hz, 10H), 0.68-0.64 (m, 8H).
¹³C NMR (126 MHz, CDCl₃) δ: 161.61, 151.70, 150.95, 146.08, 142.78, 141.38, 140.45, 139.27, 137.85, 136.75, 135.04, 132.38, 129.03, 128.22, 128.04, 127.35, 126.90, 126.08, 125.30, 124.71, 124.47, 123.85, 122.92, 120.19, 119.84, 108.41, 55.22, 46.37, 40.41, 37.99, 31.96, 31.93, 31.49, 31.42, 30.11, 29.72, 29.70, 29.68, 29.62, 29.42, 29.37, 26.44, 23.77, 22.71, 22.57, 21.45, 14.13, 14.00.

Compound 15
¹H (300 MHz, CDCl₃) δ: 9.02 (d, J= Hz, 2H), 7.75-7.72 (m, 4H), 7.68 (d, J= Hz, 2H), 7.63 (s, 2H), 7.54 (d, J= Hz, 2H), 7.38-7.34 (m, 6H), 4.19-4.10 (m, 4H), 2.02 (t, J= 8.5 Hz, 10H), 1.45-1.32 (m, 16H), 1.14-1.07 (m, 24H), 0.96 (t, J = 7.4 Hz, 6H), 0.90 (t, J = 6.7 Hz, 6H),0.77 (t, J = 7.0 Hz, 12H), 0.70-0.65 (m, 8H).
¹³C NMR (126 MHz, CDCl₃) δ 161.96, 151.96, 151.22, 150.77, 142.31, 140.40, 139.91, 137.03, 132.04, 128.61, 127.74, 127.10, 125.35, 124.38, 123.10, 120.44, 120.38, 120.12, 108.36, 55.40, 46.13, 40.49, 39.47, 31.60, 30.61, 30.59, 29.80, 28.72, 23.93, 23.89, 23.28, 22.69, 14.24, 14.12, 10.81.

Compound 16
¹H (500 MHz, CDCl₃) δ: 9.36 (s, 2H), 7.74-7.71 (m, 4H), 7.65-7.61 (m, 6H), 7.37-7.33 (m, 6H), 4.12 (d, J= 7.62 Hz, 4H), 2.02 (t, J = 8.07 Hz, 10H), 1.37 (m, 12H), 1.25-1.22 (m, 42H), 1.13-1.06 (m, 22H), 0.86-0.83 (m, 10H), 0.76 (t, J= 6.94 Hz, 10H), 0.68-0.64 (m, 8H).
¹³C NMR (126 MHz, CDCl₃) δ: 161.90, 152.23, 151.90, 151.21, 144.62, 142.14, 140.46, 140.24, 139.39, 133.00, 130.61, 127.94, 127.68, 127.09, 125.31, 123.09, 120.42, 120.30, 120.10, 114.93, 108.57, 55.41, 46.77, 40.53, 38.09, 32.07, 32.06, 31.62, 31.37, 30.23, 29.84, 29.82, 29.76, 29.71, 29.53, 29.49, 26.40, 23.91, 22.84, 22.71, 14.26, 14.13, 0.14.

Compound 17
¹H (500 MHz, CDCl₃) δ: 9.0 (d, J = 4.0 Hz, 2H), 7.77-7.74 (m, 4H), 7.71-7.67 (m, 4H), 7.53 (d, J = 4.0 Hz, 2H), 7.47-7.46 (m, 2H), 7.39-7.34 (m, 4H), 4.17-4.08 (m, 4H), 1.99 (m, 2H), 1.55 (s, 12H), 1.45-1.31 (m, 20H), 0.94 (t, J= 7.4 Hz, 6H), 0.89 (t, J = 6.8 Hz, 6H)
¹³C NMR (126 MHz, CDCl₃) δ 161.97, 154.76, 154.13, 150.55, 140.34, 139.95, 138.53, 137.03, 132.31, 128.73, 127.96, 127.35, 125.55, 124.46, 122.85, 120.81, 120.44, 108.38, 47.18, 46.16, 39.47, 30.64, 28.79, 27.29, 23.91, 23.30, 14.26, 10.80, 0.14.

Compound 18
¹H (500 MHz, CDCl₃) δ: 8.53 (d, J= 3.6 Hz, 2H), 7.76-7.72 (m,8H), 7.37-7.34 (m, 6H), 7.02 (d, J= 3.6 Hz, 2H), 4.28 (d, J= 7.7 Hz, 4H), 2.11 (m, 2H), 2.03 (t, J = 8.1 Hz, 8H), 1.45-1.39 (m, 12H), 1.31-1.21 (m, 36H), 1.13-1.05 (m, 24H), 0.85-0.81 (m, 12H), 0.75 (t, J = 7.0 Hz, 12H), 0.67-0.63 (m, 8H).
¹³C NMR (126 MHz, CDCl₃) δ 161.41, 157.75, 151.80, 151.19, 144.16, 142.34, 140.48, 133.16, 128.22, 127.79, 127.13, 123.89, 123.11, 120.35, 120.14, 118.80, 109.16, 107.07, 55.42, 47.38, 40.64, 38.15, 32.05, 31.95, 31.66, 30.33, 29.98, 29.88, 29.70, 29.49, 26.60, 26.56, 23.92, 22.80, 22.79, 22.72, 14.24, 14.22, 14.11.

(Example 1) Thin Films
A solution of Compound 1 in chloroform was spin-coated on a precleaned fused silica substrate to form a thin film. In a similar way, thin films of Compounds 2 to 4 were also formed.
The formed thin films were used to evaluate their potential for organic lasers. The thin films were photo-excited by a pulsed nitrogen laser at 337 nm. The pulse duration of the pump laser is 3.5 ns and its repetition rate is 20 Hz. The pump intensity is controlled using a set of neutral density filters. The pump beam is focused into a 0.5 cm × 0.08 cm stripe. An optical fiber connected to a charge-coupled device spectrometer was used to measure the emission spectra from the edge of the organic layers. The emission spectra were measured at various pump intensity. At low excitation intensities, the PL spectra were broad and independent of the pump intensity. At high excitation intensities, ASE occurred and a spectral narrowing of the emission band was observed. The ASE threshold and a peak wavelength of ASE were determined. The results are summarized in Table 1.

(Example 2) Optically pumped distributed feedback (DFB) organic laser
Glass substrates are cleaned by ultrasonication using neutral detergent, pure water, acetone, and isopropanol followed by UV-ozone treatment. A 100-nm-thick layer of SiO₂, which will become the DFB grating, is sputtered at 100 °C onto glass substrates. The argon pressure during the sputtering is 0.66 Pa. The RF power is set at 100 W. Substrates are cleaned by ultrasonication using isopropanol followed by UV-ozone treatment. The SiO₂ surfaces are treated with hexamethyldisilazane (HMDS) by spin coating at 4,000 rpm for 15 s and anneal at 120 °C for 120 s. A resist layer with a thickness of around 70 nm is spin-coated on the substrates at 4,000 rpm for 30 s from a ZEP520A-7 solution (ZEON Co.) and bake at 180 °C for 240 s.
Electron beam lithography is performed to draw grating patterns on the resist layer using a JBX-5500SC system (JEOL) with an optimized dose of 0.1 nC cm^-2. After the electron beam irradiation, the patterns are developed in a developer solution (ZED-N50, ZEON Co.) at room temperature. The patterned resist layer is used as an etching mask while the substrate is plasma etched with CHF₃ using an EIS-200ERT etching system (ELIONIX). To completely remove the resist layer from the substrate, the substrate is plasma-etched with O₂ using a FA-1EA etching system (SAMCO). The etching conditions are optimized to completely remove the SiO₂ from the grooves in the DFB until the SiO₂ surfaces are exposed. The gratings formed on the SiO₂ surfaces are observed with SEM (SU8000, Hitachi). EDX (at 6.0 kV, SU8000, Hitachi) analysis is performed to confirm complete removal of SiO₂ from ditches in the DFB. Cross section SEM is measured by Kobelco using a cold-field-emission SEM (SU8200, Hitachi High-Technologies). The gratings composed of second-order Bragg scattering region are thus prepared onto SiO₂ over 5×5 mm² area. Grating periods (Λ) of the second-order region are for example from 390 to 510 nm, which are chosen based on the Bragg condition:
where m is the order of diffraction, λ_Bragg is the Bragg wavelength, and n_eff is the effective refractive index of the gain medium.
The DFB substrates are cleaned by conventional ultrasonication. A chloroform solution of Compound 1 and 4,4’-bis(N-carbazolyl)-1,10-biphenyl (CBP) (weight ratio, 1-10 : 99-90) is spin-coated on top of the DFB substrates to form a light-emitting layer of 240 nm thick. A 2 μm thick CYTOP polymer layer is directly formed on top the structure by spin-coating and then cover by a sapphire lid with a thermal conductivity of 25 W m^-1 K^-1 at 300 K to fabricate a second-order DFB laser with the structure glass / SiO₂ / Compound 1:CBP / CYTOP / sapphire lid.
The lasing threshold and a peak wavelength of lasing were determined. The results are summarized in Table 2.

Claims

An organic solid-state laser containing a compound represented by the following formula (1):
wherein:
R¹ and R² each independently represent a substituted or unsubstituted alkyl group;
Het¹ and Het² are each independently represented by one of the following formulae (2) to (4):
wherein X¹ to X⁵ each independently represent O or S;
R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group;
R³ and R⁴ may be taken together to form a ring;
m¹ and m² each independently represent 0 or 1;
the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other;
each * represents a bonding site;
n1 and n2 are each independently an integer of 1 to 5, and
G¹ and G² each independently represent a hydrogen atom or a substituent;
provided that the compound is free of recurring units.
The organic solid-state laser according to Claim 1, wherein R¹ and R² are the same.
The organic solid-state laser according to Claim 1 or 2, wherein Het¹ and Het² are the same, and G¹ and G² are the same.
The organic solid-state laser according to any one of Claims 1 to 3, wherein the compound has a symmetric structure.
The organic solid-state laser according to any one of Claims 1 to 4, wherein R¹ and R² are each independently a substituted or unsubstituted branched alkyl group.
The organic solid-state laser according to Claim 5, wherein R¹ and R² are each independently a group represented by
wherein R⁹ and R¹⁰ each independently represent a substituted or unsubstituted alkyl group; and * represents a bonding site.
The organic solid-state laser according to any one of Claims 1 to 6, wherein Het¹ and Het² are each independently represented by the formula (2).
The organic solid-state laser according to any one of Claims 1 to 6, wherein Het¹ and Het² are each independently represented by the formula (3).
The organic solid-state laser according to Claim 8, wherein m1 is 0.
The organic solid-state laser according to Claim 8, wherein m1 is 1.
The organic solid-state laser according to any one of Claims 1 to 6, wherein Het¹ and Het² are each independently represented by the formula (4).
The organic solid-state laser according to Claim 11, wherein m2 is 0.
The organic solid-state laser according to Claim 11, wherein m2 is 1.
The organic solid-state laser according to any one of Claims 1 to 13, wherein G¹ and G² are each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group.
The organic solid-state laser according to Claim 14, wherein G¹ and G² are each independently an aryl group substituted by a disubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkylthio group.
The organic solid-state laser according to Claim 14, wherein G¹ and G² are each independently an alkynyl group substituted by a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
The organic solid-state laser according to any one of Claims 1 to 16, wherein X¹, X² and X⁴ are O.
The organic solid-state laser according to any one of Claims 1 to 16, wherein X¹, X² and X⁴ are S.
A compound represented by the following formula (1):
wherein:
R¹ and R² each independently represent a substituted or unsubstituted alkyl group;
Het¹ and Het² are each independently represented by one of the following formulae (2) to (4):
wherein X¹ to X⁵ each independently represent O or S;
R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group;
R³ and R⁴ may be taken together to form a ring;
m1 and m2 each independently represent 0 or 1;
the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other;
each * represents a bonding site;
n1 and n2 are each independently an integer of 1 to 5, and
G¹ and G² each independently represent a substituent;
provided that the compound is free of recurring units, and cyano groups.
Use of a compound represented by the following formula (1) as an emitter in an organic solid-state laser:
wherein:
R¹ and R² each independently represent a substituted or unsubstituted alkyl group;
Het¹ and Het² are each independently represented by one of the following formulae (2) to (4):
wherein X¹ to X⁵ each independently represent O or S;
R³ to R⁸ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group;
R³ and R⁴ may be taken together to form a ring;
m1 and m2 each independently represent 0 or 1;
the dashed lines and the double bond in parentheses represent a monocyclic or polycyclic structure through which the right moiety and the left moiety outside the parentheses are conjugated to each other;
each * represents a bonding site;
n1 and n2 are each independently an integer of 1 to 5, and
G¹ and G² each independently represent a hydrogen atom or a substituent;
provided that the compound is free of recurring units.