KR20230049852A - Achiral liquid crystal composition comprising a helical nanofilament and circularly polarized device comprising the same - Google Patents

Abstract

According to the present invention, a non-chiral liquid crystal composition including a helical nanofilament binary mixture system and a circularly polarized device including the same are disclosed. The non-chiral liquid crystal composition comprises: a helical nanofilament binary mixture system including a curved liquid crystal compound forming a first helical nanofilament (HNF) structure and a curved liquid crystal compound forming a second helical nanofilament structure; and a light emitting body aligned along the helix of the helical nanofilament binary mixture system. In addition, the curved liquid crystal compound forming the second helical nanofilament structure includes a nematic phase (N-HNF).

Description

A chiral liquid crystal composition comprising a binary mixture of helical nanofilaments and a circularly polarizing device comprising the same

The present invention relates to an achiral liquid crystal composition and a circular polarization device including the same. It relates to an achiral liquid crystal composition capable of inducing and a circularly polarizing device including the same.

Recently, since cholesteric liquid crystals and chiral liquid crystals that emit light in the form of circular polarization have completely different optical properties from the nematic phase in a complex order structure, their application possibilities are attracting attention.

Circularly polarized light-emitting materials are attracting attention as they are expected to be applied to displays, optical communications, sensors, and security fields. In particular, with respect to the display, if polarized light is emitted, the need for a polarizer is eliminated, which is why the light extraction efficiency is maximized.

In addition, in displays using circularly polarized light, the transmittance of light is reduced by 50% due to the circularly polarized plate, so the importance of the circularly polarized element is drawing attention.

In general, it is common sense that a circularly polarized light emitting material is designed by using a molecule into which a stereogenic center has been introduced so that it is only an optical isomer in either right or left direction chemically, or by mixing these molecules with other materials. Since these optical isomers in a specific rotational direction have a molecularly very complex structure, not only are they difficult to synthesize, but it is also difficult to separate only the optical isomers in a specific rotational direction.

However, many problems arise in practical applications due to several problems of the circular polarization device. In particular, problems that need to be urgently addressed for the application of circular polarization devices lie in the complexity and improvement of fabricating chiral nanomaterials.

In previous studies, HNFs (helical nanofilaments) composed of bent-core molecules have a small domain size (difference in absorption of left or right circular polarized light, causing a photoactive effect), and CD (Circular Dichroism) Although the size of the signal is small, a technique that has a phenomenon in which the size of the domain increases and the CD value is amplified by mixing rod-shaped liquid crystals (Rod-LC) together has been studied.

However, since conventional studies show a relatively small circular polarization asymmetry value (glum) of the order of 3 to 4 x 10 ^-3 , circular polarization light emission can be induced to a larger circular polarization asymmetry value (glum). It is necessary to study the ural liquid crystal composition.

Korean Patent Registration No. 10-0938181, "Dichroic dye for polarizing film, curable polarizing film composition containing the same, and polarizing plate having a polarizing film formed therefrom"

An embodiment of the present invention is a helical nanofilament binary mixture system comprising a bent liquid crystal compound forming a helical nanofilament (HNF) structure and a bent liquid crystal compound forming a helical nanofilament structure having a nematic phase. It is intended to provide an achiral liquid crystal composition capable of improving circular polarization asymmetry value (glum) using the same and a circular polarization device including the same.

An embodiment of the present invention is an achiral property capable of controlling the domain size by adjusting the mixing ratio of a bent liquid crystal compound forming a spiral nanofilament structure and a bent liquid crystal compound forming a spiral nanofilament structure having a nematic phase. It is intended to provide a liquid crystal composition and a circular polarization device including the liquid crystal composition.

An achiral liquid crystal composition according to an embodiment of the present invention includes a bent liquid crystal compound forming a first helical nanofilament (HNF) structure and a bent liquid crystal compound forming a second helical nanofilament structure. spiral nanofilament binary mixture system; and a light emitting body aligned along the spiral of the spiral nanofilament binary mixture system, wherein the bent liquid crystal compound forming the second spiral nanofilament structure includes a nematic phase (N-HNF).

The mixing ratio of the bent liquid crystal compound (HNF) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF) forming the second spiral nanofilament structure may be 7:3 to 5:5. .

The phase of the achiral liquid crystal composition may be adjusted according to the cooling temperature.

The bent liquid crystal compound forming the first helical nanofilament structure (HNF) and the bent liquid crystal compound (N-HNF) forming the second helical nanofilament structure undergo phase transition as shown in [Equation 1] below according to temperature. It can be.

[Equation 1]

HNF (Iso, isotropic phase) + N-HNF (Iso, isotropic phase) => HNF (B4 phase) + N-HNF (Iso, isotropic phase) => HNF (B4 phase) + N-HNF (N, nematic phase) phase) => HNF (phase B4) + N-HNF (phase B4) => HNF (phase B4) + N-HNF (Cr, crystal phase)

The curved liquid crystal compound forming the first spiral nanofilament structure (HNF) may be a compound represented by Chemical Formula 1 below.

[Formula 1]

In Formula 1, n is an integer from 7 to 16.

The bent liquid crystal compound (N-HNF) forming the second helical nanofilament structure may be a compound represented by Formula 2.

[Formula 2]

The light emitting body may be an organic light emitting body.

The light emitting body may be of Formula 3 below.

[Formula 3]

A circular polarization device according to an embodiment of the present invention includes an achiral liquid crystal composition according to an embodiment of the present invention.

The achiral liquid crystal composition may emit circularly polarized light.

According to an embodiment of the present invention, a spiral nanofilament binary mixture system including a bent liquid crystal compound forming a spiral nanofilament structure and a bent liquid crystal compound forming a spiral nanofilament structure having a nematic phase is used, and the circularly polarized light is asymmetric. An achiral liquid crystal composition capable of improving glut and a circularly polarizing device including the same can be provided.

According to an embodiment of the present invention, the achiral achiral domain size can be controlled by adjusting the mixing ratio of the bent liquid crystal compound forming the spiral nanofilament structure and the bent liquid crystal compound forming the spiral nanofilament structure having a nematic phase. A liquid crystal composition and a circularly polarizing device including the composition may be provided.

1 is a schematic diagram showing a liquid crystal compound according to an embodiment of the present invention.
2 is an image showing a polarization microscope (POM) measurement result of an achiral liquid crystal composition according to Comparative Example 1, and FIG. 3 is a polarization microscope (POM) measurement result of a chiral liquid crystal composition according to Example 1 , Figure 4 is an image showing the polarization microscope (POM) measurement result of the achiral liquid crystal composition according to Example 2, Figure 5 is the polarization of the chiral liquid crystal composition according to Example 3 6 is an image showing a polarization microscope (POM) measurement result of the non-chiral liquid crystal composition according to Comparative Example 2.
7 is an image showing a polarization microscope (POM) measurement result according to the phase change of the achiral liquid crystal composition according to Example 2.
8 is a graph showing the results of measuring the g value of CPL (Circularly Polarizing Light) according to the temperature of the achiral liquid crystal composition according to Example 2 according to each phase.
9 is a graph showing results obtained by measuring a Circularly Polarizing Light (CPL) signal according to the wavelength of the achiral liquid crystal composition according to Example 2 according to each phase.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements or steps in a stated component or step.

As used herein, “embodiments,” “examples,” “aspects,” “examples,” and the like should not be construed as indicating that any aspect or design described is preferred or advantageous over other aspects or designs. It is not.

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless otherwise stated or clear from the context, the expression 'x employs a or b' means any one of the natural inclusive permutations.

Also, the singular expressions “a” or “an” used in this specification and claims generally mean “one or more,” unless indicated otherwise or clear from context to refer to the singular form. should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and / or change of technology, convention, preference of technicians, etc. Therefore, terms used in the following description should not be understood as limiting technical ideas, but should be understood as exemplary terms for describing the embodiments.

In addition, in certain cases, there are also terms arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the corresponding description section. Therefore, terms used in the following description should be understood based on the meaning of the term and the contents throughout the specification, not simply the name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Meanwhile, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the terminology used in this specification is a term used to appropriately express the embodiment of the present invention, which may vary according to the intention of a user or operator or customs in the field to which the present invention belongs. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

1 is a schematic diagram showing an achiral liquid crystal composition according to an embodiment of the present invention.

The achiral liquid crystal composition according to an embodiment of the present invention includes a curved liquid crystal compound 110 forming a first helical nanofilament (HNF) structure and a curved liquid crystal compound forming a second helical nanofilament structure. The curved liquid crystal compound 120, which includes a spiral nanofilament binary mixture system including (120) and a light emitting body 130 aligned along a spiral of the spiral nanofilament binary mixture system, and forms a second spiral nanofilament structure, It includes a nematic phase (N-HNF).

Therefore, the achiral liquid crystal composition according to an embodiment of the present invention includes a bent liquid crystal compound (HNF, 110) forming a first helical nanofilament structure and a bent liquid crystal compound (N N forming a second helical nanofilament structure). -HNF, 120) can be used to improve the circular polarization asymmetry value (glum) by using a binary mixture system of helical nanofilaments.

More specifically, the B4 phase is close to a semi-crystal/crystal phase, whereas the nematic phase is an intermediate phase between a solid and a liquid and may have a state of high fluidity. Therefore, the achiral liquid crystal composition according to an embodiment of the present invention includes a binary mixture of helical nanofilaments that has all of these properties, increases thermal motion, and has an ideal chiral supramolecular structure in the B4 phase. A polarization asymmetry value (glum) may be improved.

At this time, the B4 phase has the same meaning as the spiral nanofilament phase (HNF phase).

Therefore, the circular polarization asymmetry value (glum) of the achiral liquid crystal composition according to an embodiment of the present invention may be 0 to 2.

An achiral liquid crystal composition according to an embodiment of the present invention includes a curved liquid crystal compound (HNF, 110) forming a multi-layered first spiral nanofilament structure and a bent liquid crystal compound (N N forming a second spiral nanofilament structure). -HNF, 120) can form a helical structure by being twisted while self-combining at room temperature. Preferably, the central axes of the spiral structures may be formed parallel to each other.

First, the achiral liquid crystal composition according to an embodiment of the present invention includes a bent liquid crystal compound (HNF, 110) forming a first spiral nanofilament structure and a bent liquid crystal compound (N N forming a second spiral nanofilament structure). -HNF, 120) including a binary mixture system of helical nanofilaments.

The achiral liquid crystal composition according to an embodiment of the present invention includes a curved liquid crystal compound (HNF, 110) forming a first helical nanofilament structure and a curved liquid crystal compound (HNF) forming a second helical nanofilament (HNF) structure. The domain size can be controlled by adjusting the mixing ratio of the liquid crystal compound (N-HNF, 120).

When the bent liquid crystal compound (HNF, 110) forming the first helical nanofilament structure or the bent liquid crystal compound (N-HNF, 120) forming the second helical nanofilament structure alone is included, the domain size may be to tens of microns, the R domain or L domain overlaps in CD (Circular dichroism) and CPL (Circularly Polarized Luminescence), and the signal value is offset, resulting in a low g value. The halal liquid crystal composition includes both a bent liquid crystal compound (HNF, 110) forming a first helical nanofilament structure and a bent liquid crystal compound (N-HNF, 120) forming a second helical nanofilament structure, thereby forming a domain As the size is increased to the level of hundreds to thousands of microns, the g value may be increased.

Preferably, the mixing ratio of the bending liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure and the bending liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure is from 7:3 to 7:3. It may be 5:5, and the bent liquid crystal compound (HNF, 110) forming a spiral nanofilament structure and the bent liquid crystal compound (N-HNF, 120) forming a spiral nanofilament structure including a nematic phase have been previously Outside the aforementioned range, there is a problem in that the size of the domain becomes small.

In addition, the achiral liquid crystal composition according to the embodiment of the present invention may have chirality (clockwise or counterclockwise direction) even though it is composed of all non-chiral liquid crystal compounds.

More specifically, the bent liquid crystal compound forming the spiral nanofilament structure is in an isotropic phase (achiral bent-core molecule) above a certain temperature, but below a certain temperature, the molecules are self-assembling while aggregating with each other. The phenomenon forms a helical nanofilament structure having a B4 phase, and at this time, the twist direction of the helical nanofilament structure can be divided 50:50 right or left, so that it can have chirality (clockwise or counterclockwise). there is.

The bent-type liquid crystal compound (HNF, 110) forming the first helical nanofilament structure has a structure including a bent-core in the center and rod-shaped wings on both sides of the bent-core, and the center displacement angle is 60°. to 120°, and may be a compound represented by Formula 1 below.

The curved liquid crystal compound (HNF, 110) forming the first helical nanofilament structure may be a compound represented by Formula 1 below.

[Formula 1]

In Formula 1, n is an integer from 7 to 16.

Preferably, the bent liquid crystal compound (HNF, 110) forming the first helical nanofilament structure is P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4 -(heptyloxy)phenyl)imino)methyl)benzoate)) may be used, but is not limited thereto.

For example, the curved liquid crystal compound (HNF) 110 forming the first helical nanofilament (HNF) structure may be used without limitation as long as it is a material forming a helical chiral supramolecular structure.

The curved liquid crystal compound (HNF) 110 forming the first helical nanofilament structure is a compound having an achiral property and is a compound in which molecules overlap each other with a mirror image.

The bent liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure may be included in an amount of 50 wt% to 70 wt% compared to the binary spiral nanofilament mixture system.

The intensity and intensity of circularly polarized light emission may vary according to the ratio, and circularly polarized light emission is not implemented only at a certain ratio.

In addition, the bent liquid crystal compound (HNF, 110) forming the first helical nanofilament structure may undergo a phase transition such as Iso-170°C-B2-150°C-B7-144°C-B4 (HNF).

Accordingly, the bent liquid crystal compound (HNF) 110 forming the first helical nanofilament structure may include a B4 phase.

The bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure includes a nematic phase, and the nematic phase has no regularity about the location of the liquid crystal compound, but is all constant in the direction of the molecular axis. It means a structure arranged or arranged in an order with orientation.

The bent-type liquid crystal compound (N-HNF, 120) forming the second helical nanofilament structure has a structure including a bent-core in the center and rod-shaped wings on both sides of the bent-core, and the center substitution angle is It may be 60° to 120°, and may be a compound represented by Formula 1 below.

The curved liquid crystal compound (N-HNF) 120 forming the second helical nanofilament (HNF) structure may be a compound represented by Chemical Formula 2.

[Formula 2]

Preferably, the bent liquid crystal compound (N-HNF, 120) forming the second helical nanofilament (HNF) structure is 5-((4-((3-Chloro-4-(octyloxy)benzoyl) oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate.

The bent liquid crystal compound (N-HNF) 120 forming the second helical nanofilament (HNF) structure may include both a B4 phase and a nematic phase.

More specifically, the bent liquid crystal compound (N-HNF, 120) forming the second helical nanofilament (HNF) structure has an isotropic (Iso) phase - a nematic phase - B4 depending on the temperature. (HNF) phase - can be phase-transformed in the order of the crystalline (Cystal) phase, and the nematic phase is mixed in the chiral environment (R or L) of the curved liquid crystal compound (HNF, 110) forming the first helical nanofilament structure. When it is affected and transitions from the nematic phase to the B4 phase, a structure can be formed in a specific chiral direction (R or L).

At this time, it is a material that directly transitions to an isotropic (Iso) phase-B4 (HNF) phase, or a material that does not have a nematic phase in the middle, such as transitioning to an isotropic (Isotropic, Iso) phase-B7 phase-B4 (HNF) phase. In this case, the second helical nanofilament (helical nanofilament, HNF) structure, such as the bent liquid crystal compound (N-HNF, 120), in which a nematic phase and a B4 (HNF) phase exist together, domain expansion and chiral amplification can be achieved better.

More specifically, the phase transition according to the temperature of the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure may be Iso-99°C-N-82°C-B4-76°C-Cr. .

The bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure is a compound having an achiral property and is a compound in which molecules overlap each other with a mirror image.

The bent liquid crystal compound (N-HNF, 110) forming the second spiral nanofilament structure may be included in an amount of 30 wt% to 50 wt% compared to the binary spiral nanofilament mixture system.

The intensity and intensity of circularly polarized light emission may vary according to the ratio, and circularly polarized light emission is not implemented only at a certain ratio.

Since the bent liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure are mutually inactive materials, the two liquid crystal materials are uniformly mixed with each other and do not affect the unique properties of each material. In addition, the degree of orientation of the curved liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure is determined through a change in the ratio of the light emitting body 130, and a structure for generating circularly polarized luminescence is determined. influence the formation

The phase of the achiral liquid crystal composition according to an embodiment of the present invention may be adjusted according to the cooling temperature.

More specifically, the bent liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure are the following [ It can be a phase transition as shown in Equation 1].

[Equation 1]

HNF (Iso) + N-HNF (Iso) ⇒ HNF (B4) + N-HNF (Iso) ⇒ HNF (B4) + N-HNF (N) ⇒ HNF (B4) + N-HNF (B4) ⇒ HNF ( B4) + N-HNF (Cr)

More specifically, liquid crystal molecules are active in thermal motion at high temperatures, but may aggregate/self-assemble in a stable form as the temperature decreases, and liquid crystal materials may exist in various phases as an intermediate phase between a solid and a liquid crystal.

Accordingly, conventionally, it was an achiral material, but as the temperature decreases, HNF (Helical nanofilament, B4 phase) is formed, and depending on the twist direction (clockwise or counterclockwise, R or L) A chiral structure can be formed.

Therefore, the achiral liquid crystal composition according to an embodiment of the present invention includes a curved liquid crystal compound (HNF, 110) forming a first spiral nanofilament structure of different materials and a bent type liquid crystal compound forming a second spiral nanofilament structure. Since the liquid crystal compound (N-HNF, 120) is included, the B4 phase in which the two materials are formed may also be different.

That is, if the twist direction of the B4 phase of the existing bending liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure is R, the bending liquid crystal compound (N-HNF, 120 forming the second spiral nanofilament structure) ) Since the material is exposed to the chiral environment in the R direction in the process of forming the B4 phase through the nematic phase, the probability of forming a helical structure twisted in the R direction may increase.

Thus, a binary mixture system of helical nanofilaments can be expressed as R+R or L+L.

Thus, the achiral liquid crystal composition according to an embodiment of the present invention may have a large circular polarization asymmetry value by having HNF (B4) + N-HNF (B4).

Helical Nanofilament (HNF) of the spiral nanofilament structure of the bent liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure The phase and B4 phase have the same meaning, and the achiral liquid crystal composition includes a bent liquid crystal compound (HNF, 110) forming a multi-layered first spiral nanofilament structure and a bent liquid crystal compound (forming a second spiral nanofilament structure) N-HNF, 120) can form a helical structure by being twisted while self-combining at room temperature. Preferably, central axes of the helical structures may be formed parallel to each other.

The cooling temperature of the achiral liquid crystal composition according to an embodiment of the present invention may be 60°C to 100°C, preferably 60°C to 70°C.

If the cooling temperature is less than 60° C., the bent liquid crystal compound (N-HNF, 120) forming the second helical nanofilament structure undergoes a phase transition to a crystalline phase and the HNF (Helical nanofilamnet, B4) structure is destroyed during crystallization. There is a problem, and when it exceeds 100 ° C., there is a problem that HNF (B4) + N-HNF (N) is not a combination of HNF (B4) + N-HNF (B4).

An achiral liquid crystal composition according to an embodiment of the present invention includes a light emitting body 130 aligned along the spiral of a binary mixture system of spiral nanofilaments.

The light emitting body 130 may be arranged according to the orientation of the binary mixture system of helical nanofilaments. That is, the light emitting body 130 may be affected by the orientation of the binary mixture system of spiral nanofilaments. At this time, the light emitting body 130 is a light emitting material that can be aligned or arranged according to the structure of the spiral nanofilament binary mixture system, and can be any light emitting material that can be aligned according to the order of liquid crystals, which means that it is arranged according to the orientation. means that can be oriented identically or similarly oriented.

Specifically, the light emitting body 130 is an organic light emitting body that moves well according to a binary mixture system of spiral nanofilaments, and the light emitting body 130 may be achiral or chiral.

More specifically, the light emitting body 130 may be PM580 Dye, which is an organic light emitting material represented by Chemical Formula 3 below.

[Formula 3]

However, this does not limit the light emitting body 130 to the above-described organic light emitting body, and various modifications and variations can be made from these descriptions by those skilled in the art.

In the light emitting body 130, a portion of the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure is substituted with the light emitting body 140 or a bent liquid crystal compound (N-HNF) forming the second spiral nanofilament structure (N-HNF). -HNF, 120) may be aligned or arranged according to the nematic phase structure of the curved liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure, and the light emitting body 130 is It may be the same as the orientation of the bent liquid crystal compound (N-HNF, 120) forming the two-helical nanofilament structure.

The light emitting body 130 may be included in an amount of 1wt% to 2wt% compared to the spiral nanofilament binary mixture system.

However, the weight ratio is a value corresponding to the specifically presented compound, and the weight ratio may vary depending on the binary mixture of spiral nanofilament materials. Therefore, what is important is that there is no problem if they are mixed in a weight ratio within a range that does not break the alignment of the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure.

Therefore, the mixing ratio of the light emitting material, which is a light emitting material, to the liquid crystal compound is not limited as described above. Those skilled in the art in the field to which the present invention pertains may make various modifications and variations from these descriptions.

The light emitting body 130 has no reactivity with the curved liquid crystal compound (HNF, 110) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF, 120) forming the second spiral nanofilament structure, and is mutually does not affect the properties.

A circular polarization device according to an embodiment of the present invention includes an achiral liquid crystal composition according to an embodiment of the present invention. Preferably, the achiral liquid crystal composition may emit circularly polarized light.

A circular polarization device according to an embodiment of the present invention includes a first electrode, a light emitting layer formed on the first electrode and including the achiral liquid crystal composition according to an embodiment of the present invention, and a second electrode formed on the light emitting layer. can include

The first electrode may be an anode electrode providing holes to the light emitting layer, and the first electrode may be formed of a transparent electrode to transmit light.

The second electrode may be a cathode electrode providing electrons to the light emitting layer, and the second electrode may be formed of a reflective electrode to reflect light.

However, it is not limited thereto, and when the work function of the first electrode is smaller than the work function of the second electrode, the first electrode may correspond to the cathode electrode.

The first electrode and the second electrode are aluminum (Al), silver (Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), indium tin oxide (ITO), indium Zinc Oxide (IZO), Aluminum Zinc Oxide (AZO), Fluorine Tin Oxide (FTO), Carbon Nano Tube (CNT), Graphene and Medium At least one may be included.

The light-emitting layer includes a spiral nanofilament binary mixture system that can have chirality (clockwise or counterclockwise direction) so that light emitted from the light-emitting layer has a polarization state that rotates in a specific direction, so that the spiral nanofilament binary mixture system is It may affect the orientation direction of the luminous body (eg, luminescent organic molecule).

The spiral nanofilament binary mixture system provides a twist angle in the thickness direction of the light emitting body so that the light emitting body can be stacked in a spiral structure. Accordingly, light generated from light emitting molecules can have a rotating polarization state.

More specifically, since the spiral nanofilament binary mixture system has a helical structure, light generated from the light emitting body may have a rotating polarization state. In addition, since the light emitting body is attached to the binary spiral nanofilament mixture system, light generated from the light emitting body by the binary spiral nanofilament mixture system may have a rotating polarization state.

In the circular polarization device according to an embodiment of the present invention, since the achiral liquid crystal composition according to the embodiment of the present invention included in the light emitting layer has a spiral stacked structure, the generated light has a polarization state rotating in a specific direction. can The light emitting layer composed of a spirally stacked spiral nanofilament binary mixture system emits first light having a polarization state rotating in a first direction toward the first electrode, and toward the second electrode, toward a second direction opposite to the first direction. Second light having a polarization state rotating in two directions may be emitted.

Therefore, the circular polarization device according to the embodiment of the present invention includes the achiral liquid crystal composition according to the embodiment of the present invention included in the light emitting layer, so that the spiral nanofilament binary mixed system has a spiral shape, thereby reducing the generated light. It is possible to maximize the imparted rotational polarization characteristics.

Example 1: HNF (80): N-HNF (20)

P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate)), 5-((4-((3 -Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate and the light-emitting PM580 Dye were mixed to form a liquid crystal mixture. After preparation, it was dissolved in chloroform solvent and stirred.

At this time, P7-O-PIMB ((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate), which is a binary mixture of spiral nanofilaments, and 5-((4-((3-Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate is 80 It was mixed (140g:60g) at a mass ratio (wt%) of :20, and PM580 Dye, a light emitting agent, was added at 2wt% for the spiral nanofilament binary mixture system.

Thereafter, chloroform was evaporated, and the liquid crystal mixture was heated to a temperature of 195° C. to 200° C. at which all of the liquid crystal mixtures were in an isotropic state, and then the liquid crystal mixture was injected into a cell made of lower and upper glass.

Thereafter, the phase transition was observed while cooling the temperature at a rate of 2 °C / min.

Example 2: HNF (60): N-HNF (40)

P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate)) and 5-((4-((3 Except for containing -Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate in a weight ratio of 60:40 It was prepared in the same way as in Example 1.

Example 3: HNF (40): N-HNF (60)

P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate)) and 5-((4-((3 Except for containing -Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate in a weight ratio of 40:60 It was prepared in the same way as in Example 1.

Comparative Example 1: HNF (100): N-HNF (0)

P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate)) and 5-((4-((3 Except for containing -Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate in a weight ratio of 100:0 It was prepared in the same way as in Example 1.

Comparative Example 2: HNF (0): N-HNF (100)

P7-O-PIMB((E)-1,3-phenylene bis(4-((E)-((4-(heptyloxy)phenyl)imino)methyl)benzoate)) and 5-((4-((3 Except for containing -Chloro-4-(octyloxy)benzoyl)oxy)benzylidene)amino)-2-methoxyphenyl 4'-(octyloxy)-[1,1'-biphenyl]-4-carboxylate in a weight ratio of 0:100 It was prepared in the same way as in Example 1.

2 is an image showing a polarization microscope (POM) measurement result of an achiral liquid crystal composition according to Comparative Example 1, and FIG. 3 is a polarization microscope (POM) measurement result of a chiral liquid crystal composition according to Example 1 , Figure 4 is an image showing the polarization microscope (POM) measurement result of the achiral liquid crystal composition according to Example 2, Figure 5 is the polarization of the chiral liquid crystal composition according to Example 3 6 is an image showing a polarization microscope (POM) measurement result of the non-chiral liquid crystal composition according to Comparative Example 2.

Referring to FIGS. 2 to 6 , Comparative Example 1 including only a bent liquid crystal compound forming a first helical nanofilament (HNF) structure or a bent liquid crystal compound forming a second helical nanofilament structure And Comparative Example 2 is a helical nanofilament containing both a bent liquid crystal compound forming a first helical nanofilament (HNF) structure and a bent liquid crystal compound forming a second helical nanofilament structure, although the domain is formed small. It can be seen that the achiral liquid crystal composition according to Examples 1 to 5 including the filamentary binary mixing system formed a very large domain compared to Comparative Examples 1 and 2.

More specifically, in Comparative Example 1 and Comparative Example 2, which alone contained a curved liquid crystal compound forming a first helical nanofilament (HNF) structure or a curved liquid crystal compound forming a second helical nanofilament structure, A CD (Circular Dichroism) signal was observed, which may also cause CPL (Circular Polarization Dichroism), but a bent liquid crystal compound forming a first helical nanofilament (HNF) structure or a second helical nanofilament structure. When the formed curved liquid crystal compound is included alone, the intensity of circularly polarized light is very weak and the uniformity is poor, and since HNF is in a crystal or semi-crystal state, it is difficult to control circularly polarized light emission on-off by electric field.

This is because, in the pure HNF state, the domain is very small, and + and - circular polarization cancel each other, so it is difficult to substantially emit strong circular polarization in one direction.

However, the helical nanofilament binary mixture system including both the bent liquid crystal compound forming the first helical nanofilament (HNF) structure and the bent liquid crystal compound forming the second helical nanofilament structure also amplifies the CD value. , and the CPL may also appear large. This is because when the bent liquid crystal compound forming the second helical nanofilament structure is mixed, the effect of increasing the domain is also shown, and + (RCPL) or LCPL may appear large and dominant in a specific domain.

7 is an image showing a polarization microscope (POM) measurement result according to the phase change of the achiral liquid crystal composition according to Example 2.

Referring to FIG. 7, a phase transition appears depending on temperature, and at 90° C., domains having chirality form a first helical nanofilament (HNF) structure, and a B4 phase and a second helical nanostructure of a bent liquid crystal compound. It can be seen that this is observed when the B4 phase of the bent liquid crystal compound forming the filament structure exists together (HNF(B4) + N-HNF(B4)).

8 is a graph showing the results of measuring the g value of CPL (Circularly Polarizing Light) according to the temperature of the non-chiral liquid crystal composition according to Example 2 according to each phase.

The g value (g value) refers to the value indicated as g _lum in the drawing and is a luminescence asymmetry constant that is a representative variable of circular polarization characteristics. This is similar to the CD spectrum Kuhn's dissymmetry factor, and is defined as a value obtained by normalizing the difference between left circular polarization (LCPL) and right circular polarization (RCPL) intensities (ie, I _LCPL and I _RCPL ) as shown in Equation 1 below.

<Calculation 1>

The g value is shown in FIG. 9 as the y value derived by Equation 1. Since the value of g according to each temperature appears to be effective only in the spiral nanofilament binary mixture system, it can be seen that the structural role of the spiral nanofilament binary mixture system is very large.

Therefore, the bent liquid crystal compound forming the first helical nanofilament (HNF) structure is self-assembled to form the helical nanofilament structure, and the bent type liquid crystal compound forming the second helical nanofilament structure is influenced by the structure. Since the type liquid crystal compound has orientation and degree of order, circularly polarized luminescence (CPL) may appear when the light emitting body is also aligned under the influence of the degree of order.

Referring to FIG. 8 , it can be seen that the achiral composition exhibits the structural reproducibility of the binary mixture system of spiral nanofilaments according to the temperature change, which re-expresses circularly polarized luminescence.

This can be confirmed by the fact that when the temperature rises and becomes an isotropic phase, the liquid crystal is not affected by HNF and the circularly polarized light emission signal disappears. there is.

9 is a graph showing results obtained by measuring a Circularly Polarizing Light (CPL) signal according to the wavelength of the achiral liquid crystal composition according to Example 2 according to each phase.

9 shows the structural reproducibility of the spiral nanofilament binary mixture system according to the measurement results of the circularly polarized luminescence. At this time, the structural reproducibility of the spiral nanofilament binary mixture system according to the phase change of the achiral liquid crystal composition is represented by the size of circularly polarized luminescence according to the electric field.

Referring to FIG. 9, it can be seen that the circularly polarized light signal is increased when all of the achiral liquid crystal compositions according to Example 2 have a B4 phase.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited to the above embodiments, and those skilled in the art in the field to which the present invention belongs can make various modifications and variations from these descriptions. this is possible Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

110: curved liquid crystal compound (HNF) forming the first helical nanofilament structure
120: a bent liquid crystal compound (N-HNF) forming a second helical nanofilament structure
130: luminous body

Claims (10)

A helical nanofilament binary mixture system comprising a bent liquid crystal compound forming a first helical nanofilament (HNF) structure and a bent liquid crystal compound forming a second helical nanofilament structure; and
a light emitting body arranged along the spiral of the spiral nanofilament binary mixture system;
including,
An achiral liquid crystal composition, characterized in that the bent liquid crystal compound forming the second spiral nanofilament structure includes a nematic phase (N-HNF).
According to claim 1,
The mixing ratio of the bent liquid crystal compound (HNF) forming the first spiral nanofilament structure and the bent liquid crystal compound (N-HNF) forming the second spiral nanofilament structure is 7:3 to 5:5 An achiral liquid crystal composition to be.
According to claim 1,
The chiral liquid crystal composition is a chiral liquid crystal composition, characterized in that the phase (Phase) is adjusted according to the cooling temperature.
According to claim 3,
The bent liquid crystal compound forming the first spiral nanofilament structure (HNF) and the bent liquid crystal compound (N-HNF) forming the second spiral nanofilament structure,
An achiral liquid crystal composition characterized by a phase transition as shown in [Formula 1] below depending on temperature.
[Equation 1]
HNF (Iso, isotropic phase) + N-HNF (Iso, isotropic phase) => HNF (B4 phase) + N-HNF (Iso, isotropic phase) => HNF (B4 phase) + N-HNF (N, nematic phase) phase) => HNF (phase B4) + N-HNF (phase B4) => HNF (phase B4) + N-HNF (Cr, crystal phase)
According to claim 1,
An achiral liquid crystal composition, characterized in that the bent liquid crystal compound forming the first spiral nanofilament structure (HNF) is a compound represented by Formula 1 below.
[Formula 1]

In Formula 1, n is an integer from 7 to 16.
According to claim 1,
An achiral liquid crystal composition, characterized in that the bent liquid crystal compound (N-HNF) forming the second spiral nanofilament structure is a compound represented by Formula 2.
[Formula 2]

According to claim 1,
The luminous body is an achiral liquid crystal composition, characterized in that the organic luminous body.
According to claim 7,
The light emitting body is a chiral liquid crystal composition, characterized in that the formula (3).
[Formula 3]

A circular polarization device comprising the achiral liquid crystal composition according to claim 1.
According to claim 9,
The achiral liquid crystal composition is circularly polarized light, characterized in that the light emission.

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