Near-infrared ray absorption and emission complex comprising carbazole-based donor and acceptor

Abstract

The present application relates to a near-infrared ray absorption and emission complex comprising a carbazole-based donor and an acceptor.

Description

Near-infrared absorbing and luminescent complexes containing carbazole-based donors and acceptors

[0001] The present invention relates to near-infrared absorbing and luminescent complexes comprising carbazole-based donors and acceptors.

[0002] Near-infrared (NIR) emitting materials are materials that emit light in the range of about 680 nm to about 2,500 nm, and can be applied in fields such as biological imaging, optical communications, data storage, and night vision technology. However, conventional NIR emitting technologies utilize the expansion of π-conjugation, and generally have nonradiative decay rate constants (k) according to the energy gap law. NR ) is improved. Therefore, sufficient quantum yield (quantum yield; Φ PL ) photoluminescence (PL) and lifetime (τ PL ) are rare.

[0003] Charge transfer complexes (CTCs) have recently attracted significant attention due to their photophysical and conductive properties, high tunability, and low manufacturing costs compared to inorganic counterparts. These properties make them suitable for application in optoelectronic devices such as organic semiconductors, organic photovoltaics, organic field-effect transistors, and flexible displays. The electric energy gap between the highest occupied molecular orbital (HOMO) and the lowest occupied molecular orbital (LUMO) of a CTC is smaller than the gaps of the individual donors or acceptors. Therefore, compared to the parent compound, CTCs often absorb and emit at red-shifted wavelengths and exhibit color changes upon complex formation. Energy gap tuning can be achieved by forming organic charge transfer complexes (CTCs) using donors and acceptors that hybridize to form new electronic states, which can induce charge transfer (CT) interactions between the donor and acceptor.

[0004] The energy levels of the donor HOMO and acceptor LUMO, as well as the degree of charge transfer between the donor and acceptor, are key considerations when tailoring the optical and conductive properties of CTCs. The degree of charge transfer is significantly influenced by the relative geometry of the donor and acceptor within the CTC, which can be controlled by molecular packing. Therefore, understanding the structure-property relationship of CTCs is crucial for their rational design.

[0005] [Prior Art Literature]

[0006] [Patent Document]

[0007] Japanese Patent Publication No. 2003-160566.

[0008] The present invention provides a near-infrared absorbing and luminescent complex comprising a carbazole-based donor and acceptor.

[0009] However, the problems that the present invention seeks to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] A first aspect of the present invention provides a near-infrared absorbing and emitting complex comprising a carbazole-based donor; and an acceptor, wherein the carbazole-based donor comprises a single carbazole; or about two or about three carbazoles linked by a linker.

[0011] A second aspect of the present invention provides an optoelectronic device comprising a near-infrared absorbing and emitting complex according to the first aspect.

[0012] A third aspect of the present invention provides a probe comprising a near-infrared absorbing and luminescent complex according to the first aspect.

[0013] The near-infrared absorbing and emitting complex according to the embodiments of the present invention can exhibit emission in a longer wavelength region (long wavelength region) compared to conventional charge transfer complexes.

[0014] The near-infrared absorbing and luminescent complex according to the embodiments of the present invention can exhibit sufficient photoluminescence (PL) and lifetime compared to conventional charge transfer complexes.

[0015] The near-infrared absorbing and luminescent composite according to the embodiments of the present invention can be applied to one or more selected from probes, photodetectors, optical waveguides, optical communication systems, night vision, bioimaging, luminescent display materials, phototransistors, lasers, and sensors.

[0016] Figure 1 is a diagram illustrating a method for preparing a compound of claim 1, wherein the compound of claim 1 is a carbazole (9H-carbazole), 4,4′-bis(N-carbazolyl)-1,1′biphenyl [4,4′-bis(N-carbazolyl)1,1′-biphenyl; CBP], 1,3-di-9-carbazolylbenzene (1,3-di-9-carbazolyl benzene; mCP), 9,9′-(1,4-phenylene)bis(9H-carbazole) [9,9′-(1,4-phenylene)bis(9H-carbazole; pCzPh]; tris(4-carbazoyl-9-ylphenyl)amine [tris(4-carbazoyl-9-ylphenyl)amine; TCTA]; 1,3,5-tris(carbazol-9-yl)benzene [1,3,5-tris(carbazol-9-yl)benzene; TriCzPh], and 7,7,8,8-tetracyanoquinodimethane (TCNQ) are the molecular structural formulas.

[0017] FIGS. 2A to 2F are images of carbazole, CBP, mCP, pCzPh, TCTA, and TriCzPh powders, respectively, in one embodiment of the present disclosure; FIG. 2G is an image of TCNQ powders, respectively, in one embodiment of the present disclosure; and FIGS. 2H to 2M are images of a complex comprising carbazole as a donor and TCNQ as an acceptor (carbazole:TCNQ); a complex comprising CBP as a donor and TCNQ as an acceptor (CBP:TCNQ); a complex comprising mCP as a donor and TCNQ as an acceptor (mCP:TCNQ); a complex comprising pCzPh as a donor and TCNQ as an acceptor (pCzPh:TCNQ); a complex comprising TCTA as a donor and TCNQ as an acceptor (TCTA:TCNQ). And an image of the resulting powder of a complex (TriCzPh:TCNQ) containing TriCzPh as a donor and TCNQ as an acceptor.

[0018] FIGS. 3a to 3e are a table (FIG. 3a) showing the energy gap between the HOMO (Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) calculated based on the orientation of each charge transfer interface, the distance between donors and acceptors, and absorbance obtained from the single crystal analysis results of TCTA:TCNQ, mCP:TCNQ, CBP:TCNQ, pCzPh:TCNQ, and carbazole:TCNQ in one embodiment of the present invention, the unit cell structure of TCTA:TCNQ (FIG. 3b), the orientation structure of two different charge transfer interfaces existing in TCTA:TCNQ (FIG. 3c), and the absorption spectra of charge transfer complexes (FIG. 3d).

[0019] FIG. 4a is an ultraviolet-visible (UV-vis) absorption spectrum of carbazole, TCNQ, and carbazole:TCNQ in one embodiment of the present disclosure, FIG. 4b is an UV-vis absorption spectrum of CBP, TCNQ, and CBP:TCNQ in one embodiment of the present disclosure, FIG. 4c is an UV-vis absorption spectrum of mCP, TCNQ, and mCP:TCNQ in one embodiment of the present disclosure, FIG. 4d is an UV-vis absorption spectrum of pCzPh, TCNQ, and pCzPh:TCNQ in one embodiment of the present disclosure, FIG. 4e is an UV-vis absorption spectrum of TCTA, TCNQ, and TCTA:TCNQ in one embodiment of the present disclosure, and FIG. 4f is an UV-vis absorption spectrum of TriCzPh, TCNQ, and TriCzPh:TCNQ in one embodiment of the present disclosure.

[0020] FIG. 5 is a steady-state fluorescence spectra of carbazole:TCNQ, CBP:TCNQ, mCP:TCNQ, and pCzPh:TCNQ, respectively, upon photoexcitation at 460 nm in one embodiment of the present invention.

[0021] Figures 6a to 6d are time-resolved PL transient decay profiles of carbazole:TCNQ at 1020 nm, CBP:TCNQ at 950 nm, mCP:TCNQ at 950 nm, and pCzPh:TCNQ at 1000 nm, respectively, upon photoexcitation at 460 nm in one embodiment of the present disclosure.

[0022] Hereinafter, with reference to the attached drawings, implementation examples and embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the implementation examples and embodiments described herein. In addition, in the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and similar parts have been designated with similar drawing reference numerals throughout the specification.

[0023] Throughout this specification, when a part is said to be "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "electrically connected" with another element in between.

[0024] Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0025] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0026] The terms "about," "substantially," and the like used in this specification are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which exact or absolute values ​​are mentioned to aid understanding of the present application.

[0027] The terms “step of” or “step of” as used throughout this specification do not mean “step for”.

[0028] Throughout this specification, the term "combination(s) thereof" included in the expressions in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expressions in the Makushi format, and means including one or more selected from the group consisting of said components.

[0029] Throughout this specification, references to “A and / or B” mean “A or B, or A and B.”

[0030] Below, the implementation examples of the present invention are described in detail, but the present invention may not be limited thereto.

[0031] A first aspect of the present invention provides a near-infrared absorbing and emitting complex comprising a carbazole-based donor; and an acceptor, wherein the carbazole-based donor comprises a single carbazole; or about two or about three carbazoles linked by a linker.

[0032] In one embodiment of the present disclosure, the linker may comprise one or more phenylene groups. In one embodiment of the present disclosure, the linker may be a phenylene group, a biphenylene group, or a 1,3,5-triphenylamine group. In one embodiment of the present disclosure, when the linker is a phenylene group, the two carbazoles may be linked at the ortho, meta, or para positions.

[0033] In one embodiment of the present invention, the donor may be one or more selected from the following chemical formulas 1 to 5:

[0034] [Chemical Formula 1]

[0035] ;

[0036] [Chemical Formula 2]

[0037] ;

[0038] [Chemical Formula 3]

[0039] ;

[0040] [Chemical Formula 4]

[0041] ;

[0042] [Chemical Formula 5]

[0043] ;

[0044] In the above chemical formula 1, the above chemical formula 2, the above chemical formula 3, the above chemical formula 4, and the above chemical formula 5,

[0045] X n is hydrogen, an alkyl group having 1 to 5 carbon atoms, an amine, or a halogen element,

[0046] Y m is hydrogen, an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, an allyl group having 3 to 10 carbon atoms, a phenyl group, or a benzyl group,

[0047] The above n is an integer from 1 to 8,

[0048] The above m is an integer from 1 to 3.

[0049] In one embodiment of the present invention, the donor is 9H-carbazole, 4,4′-bis(N-carbazolyl)-1,1′-biphenyl [4,4′-bis(N-carbazolyl)-1,1′-biphenyl; CBP], 1,3-di-9-carbazolyl benzene (mCP), 9,9'-(1,4-phenylene)bis(9H-carbazole) [9,9'-(1,4-phenylene)bis(9H-carbazole; pCzPh], 9H-carbazole, tris(4-carbazoyl-9-ylphenyl)amine [tris(4-carbazoyl-9-ylphenyl)amine; TCTA), and 1,3,5-tris(carbazol-9-yl)benzene [1,3,5-tris(carbazol-9-yl)benzene; triCzPh] may be one or more selected from:

[0050] [Compound 1]

[0051] ;

[0052] [Compound 2]

[0053] ;

[0054] [Compound 3]

[0055] ;

[0056] [Compound 4]

[0057] ;

[0058] [Compound 5]

[0059] ;

[0060] [Compound 6]

[0061] .

[0062] In one embodiment of the present invention, as the length of the linker decreases, the degree of charge transfer may increase.

[0063] In one embodiment of the present invention, the acceptor may be, but is not limited to, 7,7,8,8-tetracyanoquinodimethane (TCNQ) represented by the following compound 7:

[0064] [Compound 7]

[0065] .

[0066] In one embodiment of the present invention, the crystal structure of the near-infrared absorbing and luminescent complex may have a single orientation including a parallel arrangement, or may have two or more orientations including a parallel arrangement and an arrangement twisted about the parallel arrangement.

[0067] In one embodiment of the present invention, the near-infrared absorbing and emitting complex may absorb near-infrared light in a wavelength range of about 500 nm to about 1,400 nm. In one embodiment of the present invention, the near-infrared absorbing and emitting complex may absorb near-infrared light in a wavelength range of about 500 nm to about 1,400 nm, about 500 nm to about 1,200 nm, about 500 nm to about 1,000 nm, or about 500 nm to about 900 nm. In one embodiment of the present invention, the near-infrared absorbing and luminescent complex may absorb near-infrared light in a wavelength range of about 510 nm to about 800 nm, about 510 nm to about 880 nm, about 510 nm to about 950 nm, about 510 nm to about 1,300 nm, or about 510 nm to about 1,100 nm.

[0068] In one embodiment of the present invention, the near-infrared absorbing and luminescent complex may emit light in a wavelength range of about 600 nm to about 1,500 nm. In one embodiment of the present invention, the near-infrared absorbing and luminescent complex has an emission wavelength of about 600 nm to about 1,500 nm, about 600 nm to about 1,400 nm, about 600 nm to about 1,300 nm, about 600 nm to about 1,200 nm, about 600 nm to about 1,100 nm, about 700 nm to about 1,500 nm, about 700 nm to about 1,400 nm, about 700 nm to about 1,300 nm, about 700 nm to about 1,200 nm, about 700 nm to about 1,100 nm, about 800 nm to about 1,500 nm, about 800 nm to about 1,400 nm, about 800 nm to about 1,300 nm, about 800 nm to about 1,200 nm, about It may emit light in a wavelength range of from about 800 nm to about 1,100 nm, from about 900 nm to about 1,500 nm, from about 900 nm to about 1,400 nm, from about 900 nm to about 1,300 nm, from about 900 nm to about 1,200 nm, or from about 900 nm to about 1,100 nm.

[0069] In one embodiment of the present invention, the near-infrared absorbing and luminescent complex may exhibit a red shift emission spectrum upon UV-vis spectroscopy.

[0070] In one embodiment of the present invention, the degree of charge transfer may increase as the molecular packing of the near-infrared absorbing and luminescent complex becomes more solid.

[0071] In one embodiment of the present invention, the emission energy can be adjusted by controlling the energy levels of the highest occupied molecular orbital (HOMO) of the donor and the lowest unoccupied molecular orbital (LUMO) of the acceptor. In one embodiment of the present invention, the intermolecular interaction between the donor and the acceptor can affect the degree of charge transfer characteristics, and as a result, the emission energy can be adjusted.

[0072] In one embodiment of the present invention, the near-infrared absorbing and luminescent complex may have a photoluminescence (PL) lifetime in the nanoseconds.

[0073] A second aspect of the present invention provides an optoelectronic device comprising a near-infrared absorbing and emitting complex according to the first aspect.

[0074] Detailed explanations of parts that overlap with the first aspect of the present application have been omitted, but the contents described in the first aspect of the present application may be equally applied even if the explanation is omitted in the second aspect of the present application.

[0075] In one embodiment of the present invention, the optoelectronic device may be one or more selected from a photodetector, an optical waveguide, an optical communication system, a night vision, a bioimaging, a light-emitting display material, a phototransistor, a laser, and a sensor, but may not be limited thereto.

[0076] A third aspect of the present invention provides a probe comprising a near-infrared absorbing and luminescent complex according to the first aspect.

[0077] Detailed descriptions of overlapping parts with the first and second aspects of the present application have been omitted, but the contents described for the first and second aspects of the present application may be equally applied even if the description is omitted in the third aspect of the present application.

[0078] In one embodiment of the present invention, the probe may emit light in a wavelength range of about 600 nm to about 1,500 nm. In one embodiment of the present invention, the probe has a wavelength of about 600 nm to about 1,500 nm, about 600 nm to about 1,400 nm, about 600 nm to about 1,300 nm, about 600 nm to about 1,200 nm, about 600 nm to about 1,100 nm, about 700 nm to about 1,500 nm, about 700 nm to about 1,400 nm, about 700 nm to about 1,300 nm, about 700 nm to about 1,200 nm, about 700 nm to about 1,100 nm, about 800 nm to about 1,500 nm, about 800 nm to about 1,400 nm, about 800 nm to about 1,300 nm, about 800 nm to about 1,200 nm, about 800 nm to about It may emit light in a wavelength range of 1,100 nm, about 900 nm to about 1,500 nm, about 900 nm to about 1,400 nm, about 900 nm to about 1,300 nm, about 900 nm to about 1,200 nm, or about 900 nm to about 1,100 nm.

[0079] In one embodiment of the present invention, the probe may be applicable to living cells. In one embodiment of the present invention, the probe may be applicable regardless of whether the cell is alive, but may not be limited thereto.

[0080] In one embodiment of the present invention, the probe may be used by injection into the body or used outside the body, but may not be limited thereto.

[0081] Hereinafter, the present invention will be described in more detail using examples. However, the following examples are provided only to help understand the present invention, and the contents of the present invention are not limited to the following examples.

[0082] [Example]

[0083] <Synthesis of charge transfer complexes>

[0084] To study the interfaces of organic charge-transfer complexes, we designed systems based on carbazole and TCNQ, known for their ease in forming charge-transfer complexes. Carbazole and TCNQ, which have planar structures and similar sizes, were utilized as electron donors and acceptors, respectively. Six carbazole-based electron donors with different structures but similar HOMO energy levels were designed to form diverse interface structures.

[0085] The synthetic methods for each compound used are as follows:

[0086] Carbazole (9H-carbazole), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolyl benzene (mCP), and 7,7,8,8-tetracyanoquinodimethane (TCNQ) were purchased from TCI and used without further purification.

[0087] 9,9'-(1,4-phenylene)bis(9H-carbazole)[9,9'-(1,4-phenylene)bis(9H-carbazole); pCzPh] was synthesized by the following method with reference to the previous literature 'Mao Mao et al., "Thermodynamics and Conformations in the Formation of Excited States and Their Interconversions for Twisted Donor-Substituted Tridurylboranes", Chem. Eur.J.2012,18, 15512-15515':

[0088] Carbazole (0.74 g, 4.4 mmol), para-diodinated benzene (0.66 g, 2 mmol), copper iodide (0.04 g, 0.2 mmol), and potassium carbonate (1.66 g, 12 mmol) were added dropwise to a 100 mL round-bottomed flask, and 12 mL of N,N-dimethylacetamide anhydride was added under a nitrogen atmosphere, followed by reflux stirring for 24 h. After the reaction was complete, the reaction mixture was cooled, toluene was added, and a hot filter was performed. Afterwards, dichloromethane and water were added, the organic layer was separated, and the moisture in the separated organic layer was removed using magnesium sulfate. The reaction mixture was concentrated using a rotary evaporator, and column chromatography was performed, and recrystallization with dichloromethane and methanol yielded a white solid (1.02 g, yield 89%).

[0089] 1 H NMR (500 MHz, CDCl3):δ= 8.20 (d,J= 4.0 Hz, 4H),δ= 7.83 (s, 4H),δ= 7.58 (d,J= 4.0 Hz, 4H),δ= 7.49 (t,J= 7.5 Hz, 4H),δ= 7.35 (t,J= 7.5 Hz, 4H).

[0090] Tris(4-carbazoyl-9-ylphenyl)amine [tris(4-carbazoyl-9-ylphenyl)amine; TCTA] was synthesized by the following method with reference to the previous literature 'Q.-D. Liu et al., "Monodisperse Starburst Oligofluorene-Functionalized 4,4′,4″-Tris(carbazol-9-yl)-triphenylamines: Their Synthesis and Deep-Blue Fluorescent Properties for Organic Light-Emitting Diode Applications", Adv. Funct. Mater. 2007,17, 1028-1030':

[0091] Carbazole (2.21 g, 13.2 mmol), tris(4-bromophenyl)amine (1.93 g, 4 mmol), copper iodide (1.08 g, 6 mmol), phenanthroline (1.08 g, 6 mmol), and potassium carbonate (3.32 g, 24 mmol) were added dropwise to a 100 mL round-bottom flask, and 40 mL of N,N-dimethylformamide anhydride was added under a nitrogen atmosphere, followed by reflux stirring for 72 hours. After the reaction was completed, the reaction mass was cooled, toluene was added, and a hot filter was performed. After that, dichloromethane and water were added, the organic layer was separated, and the water in the separated organic layer was removed using magnesium sulfate. After concentrating the reaction mass using a rotary evaporator, column chromatography was performed, and recrystallization with dichloromethane and methanol was performed to obtain a white solid (2.12 g, yield 72%).

[0092] 1 H NMR (500 MHz, CDCl3):δ= 8.17 (d,J= 7.7 Hz, 6H),δ= 7.58 (m,J=8.8 Hz, 6H),δ= 7.53 (m,J= 10.9 Hz, 12H),δ= 7.46 (t,J= 16.4 Hz, 6H),δ= 7.31 (t,J= 15.6 Hz, 6H).

[0093] 1,3,5-Tris(carbazol-9-yl)benzene [1,3,5-tris(carbazol-9-yl)benzene; triCzPh] was synthesized by the following method with reference to the previous literature 'Mao Mao et al., "Thermodynamics and Conformations in the Formation of Excited States and Their Interconversions for Twisted Donor-Substituted Tridurylboranes", Chem. Eur. J.2012,18, 15512-15522':

[0094] Carbazole (0.74 g, 4.4 mmol), ortho-tribromide benzene (0.66 g, 2 mmol), copper iodide (0.04 g, 0.2 mmol), and potassium carbonate (1.66 g, 12 mmol) were added dropwise to a 100 mL round-bottomed flask, and 18 mL of N,N-dimethylacetamide anhydride was added under a nitrogen atmosphere, followed by reflux stirring for 24 h. After the reaction was complete, the reaction mass was cooled, toluene was added, and a hot filter was performed. Afterwards, dichloromethane and water were added, the organic layer was separated, and the moisture of the separated organic layer was removed using magnesium sulfate. The reaction mass was concentrated using a rotary evaporator, and column chromatography was performed, and recrystallization with dichloromethane and methanol gave a white solid (1.12 g, yield 65%).

[0095] 1 H NMR (500 MHz, CDCl3):δ= 8.17 (d,J= 7.7 Hz, 6H),δ= 7.96 (s, 3H),δ= 7.67 (d,J= 8.3 Hz, 6H),δ= 7.63 (t,J= 15.4 Hz, 6H),δ= 7.34 (t,J= 15.0 Hz, 6H).

[0096] All other reagents and chemicals were commercially available and used directly.

[0097] Referring to Figure 1, carbazole, CBP, mCP pCzPh, TCTA, and TriCzPh, which are composed of electron-donating carbazole moieties, contain various linkers between the carbazole groups and serve as a model series to investigate the effects of mutual orientation and distance between donor groups.

[0098] Charge transfer complexes were synthesized by the solvent-assisted grinding method of carbazole, CBP, mCP, pCzPh, TCTA, and TriCzPh with TCNQ, respectively. First, powders of carbazole alone, carbazole-based donors CBP, mCP, pCzPh, TCTA, and TriCzPh (respectively, see Figure 2 a to f), and electron acceptor TCNQ (refer to Figure 2 g) were dropped into a pestle. A few drops of solvent (toluene, dichloromethane, or chloroform) were added every 2 minutes and ground until the powder turned black, thereby obtaining charge transfer complexes (CTC) powders (refer to Figure 2 h to m).

[0099] Polystyrene (10 mg / mL) dissolved in toluene was dropped onto a quartz slide heated to 50°C and evaporated to obtain a thin film on a polystyrene matrix. The obtained CTC powders (carbazole:TCNQ, CBP:TCNQ, mCP:TCNQ, pCzPh:TCNQ, and TCTA:TCNQ) were each suspended in n-hexane and dropped onto a quartz slide on a polystyrene matrix until each suspension solution was completely consumed, thereby obtaining carbazole:TCNQ (Example 1), CBP:TCNQ (Example 2), mCP:TCNQ (Example 3), pCzPh:TCNQ (Example 4), and TCTA:TCNQ (Example 5) CTC films, respectively. The CTC powder (TriCzPh:TCNQ) obtained above was fixed on a thin film on a polystyrene matrix to obtain a CTC film (Example 6).

[0100] [Experimental Example]

[0101] The UV-visible absorption spectra of Examples 1, 2, 3, 4, 5, and 6 were measured with a Hitachi U-3900 spectrofluorometer equipped with an integrating sphere in the range of 300 nm to 900 nm; or a JASCO V-770 spectrofluorometer equipped with an integrating sphere in the range of 300 nm to 1,500 nm; and steady-state photoluminescence emission spectroscopy was performed on a HORIBA Fluoromax-4 spectrophotometer. Time-resolved photoluminescence (PL) experiments were performed using a self-built time-correlated single photon counting (TCSPC) setup (Becker & Hickl, SPC-130N board) with a Ti:Sapphire laser (Spectra-Physics, MaiTai BB) with a repetition rate of 80 MHz and a wavelength of 920 nm. The output wavelength of 920 nm was reduced to a repetition rate using a pulse picker and then frequency amplified by a β-barium borate (β-BaB2O4; BBO) crystal to obtain an excitation wavelength of 460 nm. Here, the excitation beam was focused on Examples 1, 2, 3, and 4, and the emission of Examples 1, 2, 3, and 4 was collimated, and then focused onto a monochromator (Spectra pro 150, Princeton Instruments / Acton Research) using two plano-convex lenses. An NIR-PMT (Hamamtsu, H10330a-75) was used as a photodetector.An appropriate long-pass filter was used to remove the 460 nm excitation beam scattered in front of the monochromator.

[0102] Cyclic voltammetry analysis results confirmed that the HOMO (Highest occupied molecular orbital) energy levels of the six electron donors were similar to each other, ranging from -5.3 eV to -5.6 eV.

[0103] Through absorption analysis, the high CT (Charge Transfer) absorption intensities and the near-infrared CT optical energy gaps of 1.6 eV or less of Examples 1 to 6 were confirmed. The optical energy gaps calculated based on the absorbance are summarized in Figure 3a. In this case, unlike CTC containing the remaining electron donors, Example 5 (TCTA:TCNQ), a carbazole trimer, exhibited a dual optical energy gap.

[0104] The energy gap between the HOMO and LUMO (lowest unoccupied molecular orbital) of the CTC is smaller than the individual energy gaps of the donor or acceptor. Therefore, CTCs often absorb and emit at red-shifted wavelengths compared to their parent compounds, and change color upon complex formation. This color change provides an easily observable indicator of the formation of CTCs. Referring to FIGS. 4a to 4f, the red-shifted absorption bands for the pristine donor and acceptor were found to be in the ranges of about 510 nm to about 800 nm, about 510 nm to about 800 nm, about 510 nm to about 880 nm, about 510 nm to about 950 nm, about 510 nm to about 1,300 nm, and about 510 nm to about 1,100 nm in Examples 1, 2, 3, 4, 5, and 6, respectively. These spectral features are clearly distinct from those of the pure donor and pure TCNQ, respectively.

[0105] In addition, single crystals were prepared through solution-phase mixing and antisolvent diffusion methods, and single crystal structure analysis was performed. As a result, it was confirmed that, unlike other charge transfer complexes having a single carbazole:TCNQ orientation in a parallel arrangement, Example 5 (TCTA:TCNQ) forms CTC interfaces with two different orientations, a parallel arrangement and a twisted arrangement (see Figures 3b and 3c). The oscillator transition according to the carbazole:TCNQ orientation was analyzed through calculations, and it was confirmed that as the parallel orientation was twisted, a red-shifted optical energy gap was formed. This is related to the transition being forbidden in the parallel orientation being allowed in the twisted orientation. Therefore, it was confirmed that the dual optical energy gap of Example 5 was the result of two different C-T interfaces of Example 5.

[0106] The spectroscopic characteristics of Examples 1, 2, 3, and 4 in the excited state (photoexcitation) at 460 nm were analyzed using steady-state PL spectroscopy. The most important property of charge transfer complexes used in optoelectronic devices is fluorescence, and the emission energy can be adjusted by adjusting the energy levels of the HOMO of the donor and the LUMO of the acceptor. In addition, the intermolecular interaction between the donor and acceptor also affects the degree of charge transfer characteristics, and consequently, the emission energy can be adjusted. The PL spectral spectra of Examples 1, 2, 3, and 4 are shown in Fig. 4 and Table 1 below. It should be noted that the range of about 850 nm to about 900 nm could not be measured due to limitations of the fluorescence measurement equipment, and this does not mean that there is no fluorescence in that region.

[0107] Example Charge transfer complex (donor: acceptor) PL spectrum (nm) Peak (nm) Example 1 Carbazole: TCNQ 700 to 1,500,975 Example 2 CBP: TCNQ 700 to 1,600,940 Example 3 mCP: TCNQ 700 to 1,600,965 Example 4 pCzPh: TCNQ 700 to 1,550,990

[0108] Referring to Table 1 above, Example 4 exhibited the greatest red-shifted emission, indicating the strongest degree of charge transfer that can occur from an ordered, tight packing. In contrast, Example 2 exhibited the least red-shift, indicating the smallest degree of charge transfer that can occur from the loosest packing.

[0109] Example Charge transfer complex (donor:acceptor) Emission wavelength (nm) Average PL lifetime (τ avg; ps) Example 1 carbazole:TCNQ1,020150 Example 2 CBP:TCNQ950650 Example 3 mCP:TCNQ950320 Example 4 pCzPh:TCNQ1,000390

[0110] The fluorescence properties of Examples 1, 2, 3, and 4 were analyzed by time-resolved fluorescence spectroscopy based on the time-correlated single photon counting (TCSPC) technique. Referring to Table 2 and Figures 6a to 6d, λ was measured at 460 nm for each photoexcitation, similar to the steady-state PL experiment. em = Time-resolved PL transient decay profiles of Examples 1, 2, 3, and 4 were monitored at 950 nm, 1,000 nm, and 1,020 nm. The PL lifetimes (τ) of Examples 1, 2, 3, and 4 were calculated from the decay fit results using a single exponential decay function in FIGS. 6a to 6d. PL ) were determined, which were 150 ps, ​​650 ps, ​​320 ps and 390 ps, ​​respectively, indicating monoexponential decay.

[0111] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

Claims

1. Carbazole-based donor; and acceptor Including As a near-infrared absorbing and luminescent complex, The above carbazole-based donor is a single carbazole; or two or three carbazoles are connected by a linker. Near-infrared absorbing and luminescent complex.

2. In paragraph 1, A near-infrared absorbing and luminescent complex, wherein the linker comprises one or more phenylene groups.

3. In paragraph 1, A near-infrared absorbing and luminescent complex wherein the donor is at least one selected from the following chemical formulae 1 to 5: [Chemical Formula 1] ; [Chemical Formula 2] ; [Chemical Formula 3] ; [Chemical Formula 4] ; [Chemical Formula 5] ; In the above chemical formula 1, the above chemical formula 2, the above chemical formula 3, the above chemical formula 4, and the above chemical formula 5, X n is hydrogen, an alkyl group having 1 to 5 carbon atoms, an amine, or a halogen element, Y m is hydrogen, an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, an allyl group having 3 to 10 carbon atoms, a phenyl group, or a benzyl group, The above n is an integer from 1 to 8, The above m is an integer from 1 to 3.

4. In paragraph 1, A near-infrared absorbing and luminescent complex wherein the donor is at least one selected from compounds 1 to 6 below: [Compound 1] ; [Compound 2] ; [Compound 3] ; [Compound 4] ; [Compound 5] ; [Compound 6] .

5. In paragraph 1, A near-infrared absorbing and luminescent complex wherein the acceptor is 7,7,8,8-tetracyanoquinodimethane (TCNQ).

6. In paragraph 1, A near-infrared absorbing and luminescent complex, wherein the near-infrared absorbing and luminescent complex emits light in a wavelength range of 600 nm to 1,500 nm.

7. An optoelectronic device comprising a near-infrared absorbing and luminescent complex according to paragraph 1.

8. In paragraph 7, An optoelectronic device comprising at least one selected from a photodetector, an optical waveguide, an optical communication system, a night vision, a bioimaging, a light-emitting display material, a phototransistor, a laser, and a sensor.

9. A probe comprising a near-infrared absorbing and luminescent complex according to paragraph 1.

10. In paragraph 9, The above probe is a probe that emits light in a wavelength range of 600 nm to 1,500 nm.

11. In paragraph 9, The above probe is a probe that can be used on living cells.

12. In paragraph 9, A probe that can be used by injection into the body or used externally.

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