KR101850691B1 - Fabrication Method of Flexible Thermoelectric Device Using Laser lift-off - Google Patents

Abstract

The present invention relates to a flexible thermoelectric element; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, And a sacrificial layer in contact with the transparent substrate so as to crystallize or recrystallize the semiconductor material of the semiconductor layer, thereby separating the transparent substrate from the transparent substrate .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible thermoelectric device,

The present invention relates to a method of manufacturing a flexible thermoelectric element using laser ablation, and more particularly, to a method of manufacturing a flexible thermoelectric element that can prevent a thermoelectric element from being damaged by a physical impact occurring during a stripping process.

The thermoelectric effect is a direct effect of heat energy and electric energy interacting with each other. It is a peltier effect found by jean charles peltier and a seebeck effect found by thomas johann seebeck. , And a device that exhibits such a thermoelectric effect is called a thermoelectric device.

The thermoelectric element includes a thermoelectric power generating device that uses a Seebeck effect to convert heat energy into electrical energy, and a cooling device that uses a Peltier effect that converts electrical energy to thermal energy. It is the material and the technology that best responds to the demand. This is widely used in industrial fields such as automobiles, aerospace, semiconductor, bio, optics, computers, power generation, and household appliances. Efforts to improve thermal efficiency are being conducted by research institutes and universities.

Generally, a thermoelectric element is formed by forming a second electrode on a ceramic lower substrate such as alumina (Al ₂ O ₃ ), forming a thermoelectric material made of N-type and P-type semiconductors on the surface of the electrode, It is customary to fabricate the structure in which the material is connected in series through the first electrode. However, these thermoelectric elements are cascade type or segment type, and it is difficult to change the shape. By using a ceramic substrate having no heavy and flexible characteristics such as alumina (Al ₂ O ₃ ) or alumina nitride (AIN) It is difficult to use it as a field requiring light weight, and it is also difficult to apply to a field requiring a flexible thermoelectric device. In addition, the P-type and N-type thermoelectric materials are formed in a bulk shape to have a length of 1 mm to several tens mm and are electrically connected in series. However, the heat loss due to the upper and lower substrates is large.

In order to overcome these technical limitations, Korean Patent No. 10-1493797 discloses that a substrate is not placed on the upper and / or lower portion of the thermoelectric element and the non-conductive flexible mesh is supported through the thermoelectric material column array, And a thermoelectric element capable of simultaneously securing mechanical stability and flexibility has been proposed. However, due to the separation of the thermoelectric elements from the substrate supporting the thermoelectric elements by an external force, there is a risk of physical damage to the thermoelectric elements during the peeling process, and there is a limit in manufacturing high output flexible thermoelectric elements.

Korean Patent No. 10-1493797

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a flexible thermoelectric device which can prevent a thermoelectric element from being damaged by a physical impact occurring during a substrate stripping process, And a method of manufacturing the flexible thermoelectric element.

Another object of the present invention is to provide a structure for manufacturing a flexible thermoelectric device which can prevent a thermoelectric element from being damaged by a physical impact which occurs during a substrate stripping process.

A method of manufacturing a flexible thermoelectric device according to the present invention includes: preparing a flexible thermoelectric device; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, And separating the transparent substrate by irradiating a laser to crystallize or recrystallize the semiconductor material of the semiconductor layer in a flexible thermoelectric device structure including a sacrificial layer having a layer contacting the transparent substrate.

A manufacturing method according to an embodiment of the present invention includes the steps of: a) providing the flexible thermoelectric element structure; And b) irradiating the semiconductor layer with the laser through the transparent substrate so as to satisfy the following expression (1).

(Relational expression 1)

100 mJ / cm ² ? P _l ? 5J / cm ²

In the relational expression 1, P _l is the laser power irradiated on the semiconductor layer.

In one embodiment of the present invention, in the step b), the laser may be irradiated twice or more so that the accumulated laser power of the irradiated laser satisfies the above-described relational expression (1).

In one embodiment of the present invention, in the step b), the interface between the semiconductor layer and the transparent substrate is defined as a reference plane, and the first direction and the second direction orthogonal to each other in- The moving distance of the center of the spot or the center line of the line when moving in the first direction or the second direction is smaller than the moving distance of the center line of the spot or the center line of the line when the laser is irradiated in the first direction and the second direction, May be narrower than the width of the spot or the width of the line.

In one embodiment according to the present invention, when the movement of the laser is investigated, the following relational expression 2 can be satisfied.

(Relational expression 2)

0.2R ₀ ? D _l ? 0.8R ₀

In equation 2, D1 is the center of the laser or the travel distance of the center of the line of spots of the first direction or the second direction, R ₀ is the width of the laser line width or of the laser spot.

In one embodiment according to the present invention, the laser may have a center wavelength of 150 to 400 nm.

In one embodiment according to the present invention, the laser may be selected from one or more of ArF laser, KrF laser, XeCl laser, XeF laser and KrCl laser.

In one embodiment according to the present invention, the semiconductor layer may be dehydrogenated by heat treatment.

In one embodiment of the present invention, the thermal conductivity of the buffer layer may be between 0.01 and 300 (W m ^-1 K ^-1 ).

In one embodiment of the present invention, the thickness of the semiconductor layer may be between 10 nm and 1 mu m.

In one embodiment of the present invention, the thickness of the buffer layer may be 0.5 to 5 mu m.

In one embodiment according to the present invention, the buffer layer may be an oxide or nitride.

In one embodiment of the present invention, the semiconductor material of the semiconductor layer is a quaternary semiconductor including silicon (Si), germanium (Ge), or silicon germanium (SiGe); Group 3-5 semiconductors including gallium arsenide (GaAs), indium phosphide (InP), or gallium phosphide (GaP); Group 2-6 semiconductors including cadmium sulfide (CdS) or zinc telluride (ZnTe); And lead sulfide (PbS); and the like.

In an embodiment according to the present invention, step a) comprises: a1) a thermoelectric column array comprising at least one N-type thermoelectric material and a P-type thermoelectric material spaced apart from each other, A first transparent substrate having an electrode and a first sacrificial layer disposed under the first electrode, a second electrode coupled to the other end of the thermoelectric material column array, and a second transparent Fabricating a substrate on which an array of thermoelectric pillars including a substrate is formed; And a2) forming a filling material in the empty space of the thermoelectric material column array.

Etching the buffer material of the buffer layer remaining in the flexible thermoelectric element and the semiconductor material caused from the semiconductor layer after step b) in one embodiment of the present invention.

The present invention relates to an array of thermoelectric pillars, comprising at least one thermoelectric material column array comprising at least one N-type thermoelectric material and a P-type thermoelectric material arranged at a distance from each other, an electrode electrically connecting the thermoelectric material of the thermoelectric material column array, A flexible thermoelectric element including a filling material filling an empty space; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, And a sacrificial layer having a layer contacting the transparent substrate.

The manufacturing method according to the present invention can effectively prevent the thermoelectric elements from being damaged by the physical impact generated during the substrate peeling process, and further, it is possible to perform the large area treatment in a very short time, and mass production of high quality flexible thermoelectric elements There are advantages to be able to.

FIG. 1 is a process chart showing a laser irradiation process in detail in a manufacturing method according to an embodiment of the present invention,
2 is a cross-sectional view of a flexible thermoelectric element structure according to an embodiment of the present invention,
FIG. 3 is a view illustrating measurement of power generation efficiency of a flexible thermoelectric device manufactured according to an embodiment of the present invention,
FIG. 4 is a graph showing a result of a bending test in which a change in electrical characteristics of a flexible thermoelectric device manufactured according to an embodiment of the present invention is measured for each bending radius of curvature.
FIG. 5 is a view showing a result of a bending test, which is performed to measure changes in electrical characteristics with respect to repeated bending of a flexible thermoelectric device manufactured according to an embodiment of the present invention.

The manufacturing method of the present invention will be described in detail with reference to the accompanying drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

The present applicant proposes a flexible thermoelectric element in which a support for physically supporting a thermoelectric substance column array and an electrode outside the thermoelectric substance column array and the electrode is not provided and the thermoelectric substance column array is bonded to the electrode, Is filled with a filling material, thereby maximizing flexibility while securing physical stability.

However, in the process of manufacturing a flexible thermoelectric element, a support (rigid substrate) for physical support must inevitably be used, and the support to be used must be removed in the manufacturing process of the flexible thermoelectric element.

As a preferred example, the flexible thermoelectric element may comprise a thermoelectric material column array, an electrode electrically connecting the thermoelectric material of the thermoelectric material column array, and a filling material filling at least the void space of the thermoelectric material column array. By adjusting the size, a very thin thin flexible thermoelectric element or a flexible thermoelectric element integrating several thousands to tens of thousands of thermoelectric columns can be realized. Due to the structure of such a flexible thermoelectric element, damage to the thermoelectric element due to physical impact during the removal of the support used in the manufacturing process, that is, damage to the junction interface between the electrode, the electrode and the thermoelectric material, .

As described above, in the manufacturing of the flexible thermoelectric element, the applicant has noted that minimizing the physical impact occurring upon removal of the support (rigid substrate) can greatly affect the quality and productivity of the flexible thermoelectric element As a result of studying various peeling methods, the present inventors have found a peeling method free from physical damage of a flexible thermoelectric element upon peeling the support, and have completed the present application.

A method of manufacturing a flexible thermoelectric device according to the present invention includes: preparing a flexible thermoelectric device; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, And separating the transparent substrate by irradiating a laser to crystallize or recrystallize the semiconductor material of the semiconductor layer in a flexible thermoelectric device structure including a sacrificial layer having a layer contacting the transparent substrate.

In detail, a method of manufacturing a flexible thermoelectric device according to the present invention includes: a thermoelectric material column array including at least one N-type thermoelectric material and a P-type thermoelectric material arranged apart from each other; A flexible thermoelectric element including an electrode to be connected and a filling material filling at least an empty space of the thermoelectric material column array; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, And separating the transparent substrate by irradiating a laser so that a semiconductor material of the semiconductor layer is crystallized and / or recrystallized in a structure for fabricating a flexible thermoelectric element including a sacrificial layer in contact with the transparent substrate.

More specifically, the buffer layer can prevent the heat generated in the semiconductor layer from being transferred to the flexible thermoelectric element during laser irradiation, and also protect the flexible thermoelectric element by reflecting the irradiated light (laser) And can physically protect the flexible thermoelectric device by absorbing the generated physical impact.

Specifically, the semiconductor layer may be an amorphous semiconductor layer, a polycrystalline crystalline semiconductor layer, or a mixed semiconductor layer in which amorphous and crystalline are mixed. In the semiconductor layer, the amorphous semiconductor material is crystallized and / or the crystalline semiconductor material is recrystallized by laser irradiation, micro cracks can be generated, and these fine cracks are coupled to each other, (Separating) the light emitting layer from the light emitting layer. Accordingly, the power of the laser beam irradiated on the semiconductor layer can be higher than the minimum power that the semiconductor material of the semiconductor layer can be crystallized or recrystallized by laser irradiation. In addition, the semiconductor layer is preferably amorphous or a mixed phase of crystalline and amorphous in that a larger amount of microcracks are generated with lower energy.

That is, the manufacturing method according to an embodiment of the present invention is a manufacturing method according to an embodiment of the present invention, in which the semiconductor material of the semiconductor layer is phase-transitin from amorphous to crystalline by laser irradiation, so that the microcracks and / The transparent substrate can be separated from the flexible thermoelectric element by fine cracks caused by the recrystallization of the polycrystalline semiconductor again. At this time, the fact that the semiconductor material is phase-changed from amorphous to crystalline is not interpreted to be limited to the fact that all semiconductor materials constituting the semiconductor layer are phase-changed into crystalline, and a part of the semiconductor material constituting the semiconductor layer is phase- Should be construed as including. In addition, the fact that the semiconductor material is recrystallized should not be construed to be limited to the fact that all of the semiconductor material constituting the semiconductor layer is recrystallized, and that a part of the crystalline material constituting the semiconductor layer is recrystallized.

The power of the laser to be irradiated can be appropriately adjusted according to the material of the semiconductor layer, but it is possible to separate the transparent substrate by microcracks generated in the semiconductor layer and to prevent damage of the flexible thermoelectric element by laser It is preferable to satisfy the relational expression (1).

(Relational expression 1)

_{^{100 mJ / cm 2 ≤ P l}} ≤ 5J / cm 2

In the relational expression 1, P _l is the laser power irradiated on the semiconductor layer.

In the case where the semiconductor layer is a quaternary semiconductor including silicon, germanium or silicon-germanium, crystallization or recrystallization which causes microcracks occurs, and in order to minimize physical impact, ).

(Relational expression 1-1)

400 mJ / cm ² ? P _l ? 3J / cm ²

In the manufacturing method according to the embodiment of the present invention, it is preferable that the laser is irradiated two or more times so that the accumulated laser power of the irradiated laser satisfies the above-mentioned relational expression (1).

This is because even if the physical impact is mitigated by the buffer layer when a large amount of fine cracks are generated and combined such that the semiconductor layer is broken by a single (once) laser irradiation, There is a risk that the thermoelectric element may be damaged.

Thus, by causing the laser to be irradiated multiple times (hereinafter referred to as laser multiple irradiation) and allowing the laser energy (cumulative laser power) to be irradiated per unit area of the semiconductor layer to satisfy the relational expression 1, . That is, a small amount of fine cracks are generated and bonded many times with a predetermined time difference, so that the semiconductor layer is broken, and the impact on the flexible thermoelectric element can be remarkably suppressed. Specifically, the laser may be irradiated two to ten times, specifically two to five times. At this time, when the laser is irradiated twice to ten times, it means that there is a certain rest period in which the laser is not irradiated until the next laser is irradiated to the one region of the semiconductor layer after the laser is irradiated . At this time, when the laser is of the pulse type, it is needless to say that the rest period is an intentional rest period longer than the inter-pulse interval. In addition, this independently, is irradiated with the laser is twice to 10 times also is, when laser power is irradiated to the area one each time when moving the laser movement Irradiation P ₀ is, after the laser irradiation all been completed, to an area 2P _It is needless to say that the powers of ₀ to 10P ₀ are irradiated.

As described above, the flexible thermoelectric element can be substantially free from physical shocks by irradiating the laser 2 to 10 times, specifically 2 to 5 times, so that the cumulative laser power satisfies the relational expression (1).

In one embodiment according to the present invention, the wavelength (central wavelength) of the laser to be irradiated is sufficient to instantaneously heat the semiconductor material of the semiconductor layer by light energy. As a specific, non-limiting example, a laser may have a wavelength (center wavelength) of 150 to 400 nm. As a more specific example, the laser may be selected from one or more of ArF laser, KrF laser, XeCl laser, XeF laser and KrCl laser, but is not limited thereto. At this time, the laser may be a pulsed laser, and the width of the pulse, the interval between pulses, the intensity of the pulse, and the like may be appropriately adjusted within the range satisfying the relational expression 1 described above and preferably the relational expression 1-1.

In one embodiment according to the present invention, the irradiated laser may be in the form of a spot or a line. The line shape may mean that a single laser generating device generates light in a line shape having a constant width. Independently, a plurality of laser generating devices are spaced apart from each other at a predetermined interval in the same direction, It may mean that light in a line shape having a width is generated. It should be noted that the shape of the spot may include various shapes such as a circle, an ellipse, a triangle, a square (square to rectangular), a pentagon, a hexagon, and an octagon.

The spot or line shaped laser can be moved and scanned in a manner that the semiconductor layer is scanned. Specifically, when the laser beam is irradiated on the fixed flexible ferroelectric element structure and the laser beam is irradiated to the semiconductor layer, or alternatively, the flexible thermoelectric device structure moves to the fixed laser generator, May be irradiated with a laser beam. The laser generating device or the flexible thermoelectric element structure can be moved so that the laser is irradiated to at least a part of the semiconductor layer or the entire region thereof.

In detail, the entire region of the semiconductor layer can be irradiated with a laser to peel off the transparent substrate. Alternatively, the transparent substrate can be separated by irradiating a laser to a part of the semiconductor layer. When a laser is irradiated on a part of the semiconductor layer, fine cracks generated in the laser-irradiated areas may be irradiated to such an extent that they can bond with each other. For example, when a laser is irradiated on a part of the semiconductor layer, the laser irradiation area may be 70% or more of the area of the semiconductor layer. In the case where a transparent substrate is peeled by irradiating a laser beam onto a part of the semiconductor layer, it is possible to reduce the processing time and cost, which is more commercial. As a specific and non-limiting example of irradiating a laser to a partial region of the semiconductor layer, the irradiation region, which is a region irradiated with a laser, may be arranged in parallel to and spaced from each other to form a plurality of lines crossing the semiconductor layer, . Needless to say, the present invention can not be limited by the specific shape of the irradiation region. As described above, the fine cracks generated in the laser-irradiated regions are combined (and / or propagated) It may be a shape that can have cracks.

In one embodiment of the present invention, the interface between the semiconductor layer and the transparent substrate is defined as a reference plane, and a spot or a line is formed on the basis of a first direction and a second direction orthogonal to each other in- the movement distance of the center of the spot or the center line of the line when moving in the first direction or the second direction is smaller than the width of the spot or the width of the line May be narrower than the width.

Concretely, at the time of laser beam irradiation, the following relation 2 can be satisfied.

(Relational expression 2)

0.2R ₀ ? D _l ? 0.8R ₀

In equation 2, D1 is the first direction or a movement distance of the center (center line) of the center of the laser spot or a laser line in the second direction, R ₀ is the width of the laser line width or of the laser spot. At this time, as described above, since the laser spot can have various shapes, the width of the laser spot can be interpreted as the shortest distance across the center of the laser spot.

In a more uniform laser multiple irradiation aspect, the moving distance of the center of the spot or the centerline of the line when moving in the first direction or the second direction may correspond to half the width of the spot or the width of the line.

Fig. 1 is a graph showing the energy of a laser irradiated on the reference plane 100 as the scan progresses, when the spot-type laser 200 having a square cross section is used as a reference, and D1 is 0.5Ro in the relational expression And is shown so as to be closer to black as the cumulative laser power is increased.

 1, the first direction and the second direction orthogonal to each other in the reference plane 100 (in-plane) are shown as x and y, and when the laser is moved in the x-axis direction, The laser irradiation state is denoted by x1, x2, x3 and x4. The laser irradiation state of the reference plane is denoted by y1, y2, and y3 every time the laser travels along the y- And y4.

When the laser is irradiated sequentially along the x- and y-axes to scan the semiconductor layer, the laser of constant intensity is irradiated to one area of the reference plane for a certain period of time, 0.5R ₀ ). At this time, if the laser power irradiated on the reference plane region per one movement is P ₀ , the laser power of the first irradiated region (A1) is Po, or the laser power of the laser irradiated on the x- As the movement is irradiated, two laser beams are irradiated to the regions overlapping each other before movement and after movement. This, and also in the x2, x3 and x4 of the laser 1 is two times of that in the irradiated area A2, A2 will have a 2P ₀ irradiation of the laser power (laser power is accumulated). After the x-axis scan is completed so as to traverse the reference plane, the x-axis scan is performed so as to move again to the y-axis movement distance (0.5R _{0 in} FIG. 1) and cross the reference plane again. as the y-axis in FIG laser moves irradiated with moving distance corresponding to half of the spot width, A3 region is irradiated the three lasers, A3 there will surveyed 3P ₀ of the laser power (cumulative laser power). movement in the y axis (y1) and then becomes the x-axis scanning achieved by moving a distance corresponding to half of the spot width, such as re-y2, y3, y4, A4 region is irradiated the four laser, A4 has the 4P ₀ The laser power (cumulative laser power) is irradiated. and then moved along the y-axis at a predetermined movement interval. Then, as shown in Fig. 1, the x-axis is moved a number of times so as to cross the reference plane again at the predetermined movement interval, It is of course possible that the entire region of the reference plane can be irradiated with the laser beam by repeating the movement inspection at the movement interval, so that all the regions except for the outermost region of the reference plane can be irradiated four times . At this time, it is needless to say that the laser can be re-irradiated so that the laser is irradiated four times in the outermost region as necessary.

1, when the semiconductor layer is scanned with a laser so that the moving distance of the laser beam to be moved is narrower than the width of the laser spot or the laser line, the local area is smaller than the laser spot or the laser line, The transparent substrate can be separated from the flexible thermoelectric element stably and reproducibly while suppressing the occurrence of abrupt physical shocks.

In the manufacturing method according to an embodiment of the present invention, the semiconductor layer may be dehydrogenated. Specifically, the semiconductor layer may be a dehydrogenated one substantially containing no hydrogen by a dehydrogenation process for removing hydrogen by heat treatment. As is known, when hydrogen is contained in an amorphous or crystalline semiconductor layer, hydrogen contained in the semiconductor layer can be removed through heat treatment at 500 DEG C or higher. This dehydrogenation treatment can be realized as an independent heat treatment step for dehydrogenation in the step of forming the sacrificial layer on the transparent substrate. Alternatively, as described later, in the step of providing the flexible thermoelectric element structure, Can be implemented during the manufacturing process of the structure. When an independent heat treatment for dehydrogenation is performed, the heat treatment can be performed at 500 ° C to 700 ° C for 10 minutes to 30 minutes.

When the semiconductor layer contains hydrogen, there is a risk that vaporization and outgassing of hydrogen may occur by laser irradiation. Vaporization and outgassing of hydrogen can have a catastrophic effect on the proposed flexible thermoelectric device which does not have a support to support the components of the thermoelectric element, as it causes a momentary and large physical impact. That is, a thermoelectric column array including at least one N-type thermoelectric material and a P-type thermoelectric material arranged to be spaced apart from each other, an electrode electrically connecting the thermoelectric material of the thermoelectric material column array, More specifically, a flexible thermoelectric device comprising a thermoelectric material column array, an electrode, and a filling material, including a filling material filling the space, is subjected to physical impact caused by vaporization and outgassing of hydrogen, The array can suffer serious physical damage.

Accordingly, the semiconductor layer may be one in which a gas source capable of generating a gas phase is removed by energy of a laser irradiated by heat treatment. As described above, one example of such a gas source is hydrogen.

In the manufacturing method according to an embodiment of the present invention, the thickness of the semiconductor layer may be a thin thickness so that microcracks generated by crystallization can be easily propagated and combined with each other. If the thickness of the semiconductor layer is too thin, the occurrence of microcracks due to crystallization or recrystallization may be reduced. If the thickness of the semiconductor layer is too thick, the microcracks are not sufficiently extended to each other, There is a risk that it will not be done. In this respect, the thickness of the semiconductor layer may be between 10 nm and 1 μm, preferably between 20 nm and 500 nm, more preferably between 40 nm and 70 nm.

The material of the semiconductor layer is not particularly limited, but the material of the semiconductor layer may be a quaternary semiconductor including silicon (Si), germanium (Ge), or silicon germanium (SiGe); Group 3-5 semiconductors including gallium arsenide (GaAs), indium phosphide (InP), or gallium phosphide (GaP); Group 2-6 semiconductors including cadmium sulfide (CdS) or zinc telluride (ZnTe); And lead sulfide (PbS); and one or more of them can be selected.

In one embodiment of the present invention, the buffer layer basically serves to prevent the heat generated in the semiconductor layer from being transferred to the thermoelectric element during laser irradiation and to prevent the micro crack from propagating to the thermoelectric element , And a thermal conductivity of at least 0.01 W m ^-1 K ^-1 or higher. The role of the thermal diffusion barrier for preventing the heat of the semiconductor layer from being conducted is to protect the thermoelectric element from heat and to prevent the light energy (laser energy) absorbed in the semiconductor layer heat from propagating outside the semiconductor layer Thereby causing crystallization of the effective semiconductor material with lower laser energy. That is, the buffer layer, which is an adiabatic layer, not only protects the flexible thermoelectric element from thermal and physical impact, but also absorbs the light energy to confine the thermal energy of the semiconductor layer instantaneously in the semiconductor layer. From the side serving as the thermal diffusion barrier such reliable, effectively, the thermal conductivity of the semiconductor layer is 0.01Wm ^-1 K ^-1 to 300 Wm ^-1 K ^-1, specifically from 100 to 300 Wm ^-1 K ^-1 can be have.

Further, the buffer layer may have a refractive index relatively lower than the refractive index of the semiconductor layer. With this difference in refractive index, a laser incident on the semiconductor layer through the transparent substrate can be reflected at the interface between the semiconductor layer and the buffer layer, and can be effectively absorbed into the semiconductor layer. Such a difference in refractive index can be reflected by the difference in refractive index even when the laser is irradiated at an angle perpendicular to the semiconductor layer even if the laser is not completely parallel light. Incidentally, the irradiation angle of the laser can be intentionally tilted at an angle that causes total internal reflection at the interface between the semiconductor layer and the buffer layer, according to Snell's law. As a specific example, the refractive index of the buffer layer may have a refractive index of 0.3 to 0.7 with respect to the refractive index of the semiconductor layer.

 The buffer layer may be an oxide or nitride. The buffer layer which is an oxide or a nitride may be an oxide of a metal element, a nitride of a metal element, an oxide of a nonmetal element or a nitride of a nonmetal element, or may be an oxide of a semiconductor material or a nitride of a semiconductor material. In this regard, the buffer layer may be an oxide or a nitride of a semiconductor material of the semiconductor layer, and may be an oxide of a semiconductor material in terms of effectively satisfying both the role of a thermal diffusion barrier, the absorption of physical impact, and the refractive index. As a specific, non-limiting example, the buffer layer may be an oxide of a quaternary semiconductor comprising silicon (Si), germanium (Ge) or silicon germanium (SiGe).

In the manufacturing method according to an embodiment of the present invention, the thickness of the buffer layer may be sufficient to absorb a physical impact generated in the semiconductor layer and to exhibit an effect of preventing thermal diffusion. However, since the material of the buffer layer remaining on the surface of the flexible thermoelectric device after the transparent substrate is separated must be removed, if the buffer layer is excessively thick, the process time may be unnecessarily prolonged and productivity may be deteriorated. In this respect, the thickness of the buffer layer according to a specific, non-limiting example may be 0.5 to 5 탆, more specifically 0.5 to 3 탆, and even more specifically 0.5 to 2 탆.

A manufacturing method according to an embodiment of the present invention includes: providing a flexible thermoelectric element structure; And irradiating the semiconductor layer with a laser through the transparent substrate to remove the transparent substrate from the flexible thermoelectric element structure. At this time, the laser is irradiated to the side of the transparent substrate positioned on the upper side and the side of the transparent substrate positioned on the upper side, independently of the other, sequentially or simultaneously, so that the two transparent substrates opposed to each other in the flexible thermoelectric device structure can be separated and removed Of course it is.

Providing a flexible thermoelectric element structure comprises: a1) a thermoelectric column array comprising at least one N-type thermoelectric material and a P-type thermoelectric material spaced apart from each other, a first electrode coupled to one end of the thermoelectric material column array, And a second transparent substrate on which a second sacrificial layer is formed, the second sacrificial layer being formed on the second electrode, the first transparent substrate having a first sacrificial layer disposed under the electrode, a second electrode coupled to the other end of the thermoelectric material column array, Fabricating a substrate on which a thermoelectric column array is formed; And a2) forming a filling material in the empty space of the thermoelectric material column array.

In detail, the step of fabricating the substrate on which the thermoelectric material column array is formed comprises the steps of: a1-1) forming a first electrode on the first transparent substrate on which the first sacrificial layer is formed and a first electrode formed on the first electrode, Type thermoelectric material is formed on the first and second substrates, a second electrode formed on the second transparent substrate on which the second sacrificial layer is formed, and a thermoelectric material formed on the second electrode in a predetermined region, Providing a second unit comprising the first unit; And a1-2) fabricating a substrate having the thermoelectric substance column array formed by connecting the first unit body and the second unit body.

Independently, the step of fabricating the substrate on which the array of thermoelectric pillars is formed comprises the steps of: a1-3) forming a first electrode on the first transparent substrate on which the first sacrificial layer is formed and a first electrode formed on the first electrode, Forming a thermoelectric column array comprising a P-type thermoelectric material and an N-type thermoelectric material; a1-4) combining the thermoelectric substance column array and the second electrode formed on the second transparent substrate on which the second sacrificial layer is formed so as to face the first transparent plate.

Independently, a1-5) forming a p-type thermoelectric material or a p-type thermoelectric material spaced apart from each other on the first support, and forming a thermoelectric material complementary to the first support on the second support so as to be spaced apart from each other ; a1-6) thermoelectric material of the first support is bonded and transferred to the first electrode formed on the first transparent substrate on which the first sacrificial layer is formed to manufacture the first unit, and thermoelectric material of the second support is transferred to the second sacrificial layer Bonding and transferring a second electrode formed on a second transparent substrate to form a second unit body; And a1-7) fabricating a substrate having the thermoelectric material array formed by connecting the first unit and the second unit.

The transparent substrate which is the first transparent substrate or the second transparent substrate has transparency that transmits at least the light to be irradiated independently and can physically support the thermoelectric element and is thermally Any material with stability can be used. For example, the first transparent substrate or the second transparent substrate may each be a quartz substrate, but the present invention is not limited thereto.

 The first sacrificial layer or the second sacrificial layer is merely referred to as a sacrificial layer formed on two transparent substrates (a first transparent substrate and a second transparent substrate) opposed to each other in the flexible thermoelectric element structure, The same or similar to one sacrificial layer.

The transparent substrate on which the sacrificial layer is formed can be manufactured by forming a buffer layer which is adiabatic with the semiconductor layer using a vapor deposition commonly used in the field of semiconductor devices in a transparent substrate. The deposition may be physical vapor deposition including sputtering or chemical vapor deposition using a precursor gas. However, the present invention is not limited to the method of manufacturing a transparent substrate on which a sacrificial layer is formed . However, as described above, the sacrifice layer is formed so as not to have a laser source, specifically, a gas source for generating a gas phase by a laser having power satisfying the relationship (1), or when the sacrifice layer contains a gas source, It is preferable that the gas generating source is removed through heat treatment. The removal of the gas source may be performed in an independent step or alternatively during the fabrication of the flexible thermoelectric device. This process may be performed by heat treatment at the time of electrode formation or heat treatment during the manufacturing process of the substrate on which the thermoelectric material column array is formed And the gas generating source in the sacrificial layer may be removed by this heat treatment.

The manufacturing method of the flexible thermoelectric device itself and the structure of the flexible thermoelectric device can be found in Korean Patent Application No. 2015-0149397, and the present invention includes all contents of Korean Patent Application No. 2015-0149397.

In detail, the electrode may be formed on the sacrifice layer of the transparent substrate on which the sacrifice layer is formed, and any method may be used as long as it is a method capable of forming electrodes (first electrode or second electrode) in a planned pattern. And may be performed by various methods such as screen printing, sputtering, evaporation, chemical vapor deposition, pattern transfer, or electrodeposition.

The electrode paste may be coated on the sacrificial layer (the first sacrificial layer or the second sacrificial layer) according to a planned pattern, and then the electrode paste may be thermally treated to form an electrode One electrode or a second electrode) can be formed.

Specifically, the electrode can be manufactured by applying an electrode paste containing a conductive material and a glass frit onto a sacrificial layer of a transparent substrate on which a sacrificial layer is formed, followed by heat treatment. The electrode paste may contain 10 to 90% by weight of the conductive material and may contain 0.1 to 20 parts by weight of the glass frit, based on 100 parts by weight of the conductive material, when the glass frit is further contained. The conductive material may include a nanostructure together with a particle or particle, and the nanostructure may be an anisotropic material having conductivity such as a carbon nanotube, a carbon nanowire, or a silver nanowire.

The conductive material may be a transition metal of Groups 3 to 12, and examples thereof include a metal such as Ni, Cu, Pt, Ru, Rh, Au, ), Cobalt (Co), palladium (Pd), titanium (Ti), tantalum (Ta), iron (Fe), molybdenum (Mo), hafnium (Hf), lanthanum ) And silver (Ag), but the present invention is not limited thereto. As a practical example, it may be desirable to use copper (Cu) in terms of high electrical conductivity, adhesion with a filler material, and low cost. Glass frit can be lead-free glass frit containing lead or lead-free glass frit without lead, but it is better than lead-free glass frit which is environmentally friendly and harmless to human body. Further, the glass frit is better than the bismuth oxide-boron oxide-zinc oxide based glass frit containing bismuth oxide, boron oxide and zinc oxide. When the electrode contains bismuth oxide-boron oxide-zinc oxide based glass frit, The binding force with the acid-based filling material can be remarkably improved. In the case of a bismuth oxide-boron oxide-zinc oxide glass frit, it may contain 60 to 90% by weight of Bi ₂ O ₃ , 10 to 20% by weight of ZnO and 5 to 15% by weight of B ₂ O _{3 in the} total weight of the glass frit have. In addition, it may further include one or two or more metal oxides selected from Al ₂ O ₃ , SiO ₂ , CeO ₂ , Li ₂ O, Na ₂ O and K ₂ O, 1 to 20% by weight. Specific examples of the bismuth oxide-boron oxide-zinc oxide-based glass frit include Bi ₂ O ₃ -ZnO-B ₂ O ₃ glass frit, Bi ₂ O ₃ -ZnO-SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ glass Frit, Bi ₂ O ₃ -ZnO-SiO ₂ -B ₂ O ₃ -La ₂ O ₃ -Al ₂ O ₃ glass frit, Bi ₂ O ₃ -ZnO-SiO ₂ -B ₂ O ₃ -TiO ₂ glass frit, or Bi ₂ O ₃ -SiO ₂ -B ₂ O ₃ -ZnO-SrO glass frit, but is not limited thereto.

Needless to say, the electrode paste may further contain various additives for the printability required according to the printing method, such as a solvent (vehicle) and a binder in addition to the conductive material and the glass frit.

After the electrode paste is applied in a pattern designed in the designed region of the sacrificial layer, a heat treatment (hereinafter referred to as electrode heat treatment) for thinning the conductive paste of the applied paste can be performed. The electrode heat treatment can be controlled to some extent according to the electrode material, but it induces dense filming so that stable electric conductivity can be maintained even with repeated physical deformation. In order to remove a gas generating source which may be contained in the semiconductor layer during the electrode heat treatment, Lt; 0 > C or more. As a concrete and practical example, the electrode heat treatment may be performed at 500 to 800 ° C, more practically at 600 to 800 ° C, and more practically at 600 to 800 ° C for 10 to 30 minutes. The atmosphere during the heat treatment of the electrode may be an atmosphere capable of protecting the electrode material from oxidation or the like, and examples thereof include vacuum, inert atmosphere, and the like, but are not limited thereto.

According to the above-described method, a first transparent substrate on which a first electrode and a first sacrificial layer are formed, and a second transparent substrate on which a second electrode and a second sacrificial layer are formed, respectively, can be manufactured.

As described above, the method of forming the thermoelectric substance column array on the transparent substrate on which the electrodes are formed after the electrodes are formed can be largely divided into three types. First, an N-type thermoelectric material or a P-type thermoelectric material is formed on a first transparent substrate on which an electrode and a sacrificial layer are formed to manufacture a first unit, a second transparent substrate on which an electrode and a sacrificial layer are formed, Forming a second unitary body by forming a thermoelectric material complementary to the material, and then joining the first unitary body and the second unitary body.

Second, a thermoelectric substance column array of an N-type thermoelectric material and a P-type thermoelectric material is formed on a first transparent substrate on which an electrode and a sacrificial layer are formed, and then an array of thermoelectric substances on the first transparent substrate, 2 transparent substrate.

Third, after forming N-type thermoelectric columns and P-type thermoelectric columns on a separate support, the N-type thermoelectric (or P-type thermoelectric) columns are transferred to a first transparent substrate on which electrodes and sacrificial layer are formed After the bonding, the support is removed to produce a first unit. P-type thermoelectric materials (or N-type thermoelectric materials) are transferred and bonded to the electrodes and the second transparent substrate on which the sacrificial layer is formed, And then the first unit and the second unit are bonded to each other.

The second method is a method in which the P-type and the N-type thermoelectric materials are both formed on the first transparent substrate and then combined with the second transparent substrate on which the electrodes and the sacrificial layer are formed in the first method, It may correspond to a modified example. In addition, the third method is to manufacture a unit body by forming a thermoelectric material on a separate support and then transferring the thermoelectric material to a transparent substrate on which an electrode and a sacrificial layer are formed, which is also a modification of the first method . Hereinafter, the first method and the third method will be described in detail, and the second method can be performed by referring to the first method and appropriately modifying the first method.

A step of forming a P-type thermoelectric material or an N-type thermoelectric material in a predetermined region on the patterned electrode may be performed. Any method may be used as long as it can form a P-type thermoelectric material or an N-type thermoelectric material in a predetermined region on the electrode. For example, a thermoelectric material paste is applied using a thermoelectric material paste Heat treatment may be performed to form a thermoelectric substance column of the polycrystal, or a monocrystal of a thermoelectric material processed into an appropriate size and shape.

In the case of a thermoelectric element provided according to an embodiment of the present invention, since a support for passing a thermoelectric material is not provided, it is possible to use a thermoelectric material of a single crystal, It is possible to utilize it even in the field where the efficiency can not be satisfied.

When the P-type thermoelectric material or the N-type thermoelectric material is formed into a polycrystalline material by using the thermoelectric material paste, the P-type thermoelectric material or the N-type thermoelectric material can be formed by a conventional printing method such as a screen printing method. In detail, a P-type thermoelectric material paste or an N-type thermoelectric material paste is applied to an upper portion of the electrode in a predetermined pattern and then thermally processed to form a thermoelectric material.

The P-type thermoelectric material paste or the N-type thermoelectric material paste may contain a P-type thermoelectric material or an N-type thermoelectric material, and may contain additives such as a binder in consideration of printability, thermal conductivity, physical strength, , A solvent, a conductive material, and / or a glass frit.

The N-type thermoelectric material and / or the N-type thermoelectric material may be a material that generates a voltage difference by a thermal gradient, and includes all of the N-type thermoelectric material and / or the P-type thermoelectric material used in a conventional thermoelectric device. Representative For example, N-type thermoelectric material is bismuth-telru ryumgye _{(Bi x Te 1-x,} x is 0 ≤ x ≤ 1 a real number) or bismuth-Tele titanium-selenium-based _{(Bi 2 Te 3-y Se} y, y (The real number 0 ≤ y ≤ 1), and the P-type thermoelectric material may be an antimony-tellurium-based (Sb _x Te _1-x , x is a real number 0 ≤ x ≤ 1) or a bismuth-antimony- (Bi _y Sb _{2 -y} Te ₃ , y is a real number satisfying 0? Y? 2), and the like.

The P-type thermoelectric substance paste or the N-type thermoelectric substance paste may be preferably adjusted in the content of the constituent components so that the thermoelectric substance column array has a thermoelectric performance index (ZT) of 0.1 or more. In one embodiment, the P-type thermoelectric material paste or the N-type thermoelectric material paste may include 10 to 90% by weight of the thermoelectric material, 5 to 50% by weight of the solvent and 2 to 10% by weight of the binder, When the glass frit is further included, the glass frit may be added in an amount of 2 to 10% by weight based on the total weight of the paste. However, it goes without saying that the present invention can not be limited by the specific material or composition of the paste for forming the P-type thermoelectric material or the N-type thermoelectric material.

The P-type thermoelectric material paste or the N-type thermoelectric material paste may be applied to the upper surface of the electrode in a designed pattern, and then the P-type thermoelectric material or the N-type thermoelectric material may be formed by heat treatment.

The first unit body and the second unit body can be manufactured by forming an electrode on a transparent substrate on which a sacrificial layer is formed as described above and forming thermoelectric materials on the electrodes. However, the first unit body may include a P-type thermoelectric material or an N-type Only one kind of thermoelectric material may be formed from the thermoelectric material and the second unit material may be formed with a thermoelectric material complementary to the thermoelectric material of the first unit material.

That is, when the thermoelectric material formed on the first unit body is the N-type thermoelectric material, the thermoelectric material formed on the second unit material may be the P-type thermoelectric material. Alternatively, when the thermoelectric material formed on the first unit material is the P- , And the thermoelectric material formed on the second unit body may be an N-type thermoelectric material.

The thermoelectric material of the first unit body and the second unit body may be arranged so that the P-type and N-type thermoelectric materials can be electrically connected through the electrodes formed in the respective unit bodies when the two unit bodies are integrally bonded, And may be arranged so as to be electrically connected in series through electrodes formed in the respective unit bodies. The thermoelectric material of the first unit and the second unit is a specific example, and when the two units are integrally combined, the P-type thermoelectric material and the N-type thermoelectric material are MxN (M is a natural number of 2 or more and N is 2 Or more natural number) matrix, and may be formed so as to have a structure that is alternately arranged in the longitudinal direction and the lateral direction.

However, as described above, the arrangement and structure of the thermoelectric material in each unit body are such that when one unit in which the P-type thermoelectric material is formed and the other unit in which the N-type thermoelectric material is formed are integrally bonded, Any arrangement and structure may be used as long as the P-type thermoelectric material and the N-type thermoelectric material can be electrically connected in series.

One of advantages of the manufacturing process of the flexible thermoelectric element is that one kind of thermoelectric material of the P type or the N type thermoelectric material is formed in the first unit material and the thermoelectric material of the first unit material is complementary to the thermoelectric material of the first unit material, The annealing optimized for each material can be performed in consideration of the kind of the thermoelectric material formed in the unit body.

For example, the optimum annealing conditions for forming the P-type thermoelectric material may vary depending on the type of the thermoelectric material contained in the P-type thermoelectric material paste, and depending on the material, annealing may be performed at a temperature of 300 to 1000 ° C have. (Bi _y Sb _{2 -y} Te ₃ , 0? Y? 2), such as Bi _0.3 Sb _1.7 Te ₃ , Bi _0.8 Sb _1.2 Te ₃ or Bi _0.5 Sb _1.5 Te ₃ , In the case of the compound, after the substrate coated with the P-type thermoelectric material paste is dried, annealing may be performed at 400 to 600 ° C for 30 to 120 minutes, preferably at 495 to 505 ° C for 30 to 80 minutes Can be performed.

Likewise, the optimum annealing conditions for the formation of the N-type thermoelectric material may vary depending on the kind of the thermoelectric material contained in the N-type thermoelectric material paste, for example, when the thermoelectric material is a bismuth-tellurium-based material (Bi _x Te _1-x , 0? X? 1), the substrate coated with the N-type thermoelectric material paste may be dried and then annealed at 350 to 550 ° C for 30 minutes to 120 minutes, preferably at 505 to 515 ° C Annealing may be performed for 60 to 120 minutes.

In this case, if the thermoelectric material paste further contains an organic binder, it is of course possible to carry out a step for decomposing and removing the organic binder before and after the annealing, and the decomposition and removal of the binder may be performed at a temperature of about 180 to 280 ° C It can be performed by heat treatment. However, it is needless to say that, even if a separate binder removing step is not performed, the binder can be decomposed and removed at the same time during the temperature raising process or the annealing process for annealing.

Further, when the thermoelectric material contains a volatile element such as tellurium (Te), annealing can be performed under an atmosphere of a volatile element (for example, tellurium atmosphere). The atmosphere of the volatile element may be supplied by supplying a volatile element separately or by supplying a volatile element powder (for example, a tellurium (Te) powder) into a heat treatment oven or a furnace where annealing is performed, And a method of inserting it together with a coated transparent substrate.

In the case of using a thermocouple monocrystal rather than a thermoelectric paste, it can be processed into a designed shape through a process such as cutting and adhered to the upper part of the electrode. The method for the adhesion is not particularly limited as long as the method can bond the electrode and the thermoelectric material. For example, the method can be carried out using a conductive adhesive. As an example, the conductive adhesive may be a silver paste containing silver, and in one embodiment, a silver paste, a Sn-Ag paste, a Sn-Ag-Cu paste or a tin- -Antimony (Sn-Sb) paste or the like may be used, but the present invention is not limited thereto.

In the case of the third method, the thermoelectric material paste is applied on a separate support instead of the electrode of the transparent substrate on which the sacrificial layer is formed, and is then annealed to form the N type thermoelectric material or the P type thermoelectric material on the support And then transferring the N-type thermoelectric material or the P-type thermoelectric material on the support to the electrode and the transparent substrate on which the sacrificial layer is formed, so that the first unit or the second unit is manufactured, similar to the first method described above have. At this time, an N-type thermoelectric material or a P-type thermoelectric material is formed on the first support and a thermoelectric material complementary to the thermoelectric material of the first support is formed on the second support, The first and second unit bodies can be manufactured by transferring the thermoelectric material to the transparent substrate having the electrode and the sacrificial layer formed thereon. A material used as a separate support may be a thermally stable material at the time of heat treatment for annealing a thermoelectric material and may be used as long as it is a material having a low binding force with a thermoelectric material such as a quartz substrate. The method of transferring the thermoelectric material formed on the support to the electrode and the transparent substrate on which the sacrificial layer is formed may be a bonding using a conductive paste (conductive adhesive) or a brazing bonding using a metal layer. However, But it is not limited thereto.

 Next, a step of physically connecting the first unit body and the second unit body to manufacture a substrate having the thermoelectric substance column array may be performed. As described above, the first structure and the second structure may be connected to each other so that the thermoelectric materials are spaced apart from each other. As shown in FIG. 2, each unit may be connected so that the P-type thermoelectric material and the N- have. For example, the connection between the units may be performed through an adhesion process. The method for bonding is not particularly limited as long as it can bond the electrode and the thermoelectric material. For example, the bonding can be performed using a conductive adhesive . As a specific example, the conductive adhesive may be a silver paste containing silver, but is not limited thereto.

After the first unit body and the second unit body are bonded, a step of forming a filler material in the empty space of the thermoelectric material column array may be performed. Even after the transparent substrate is removed by the filling material, the physical stability and mechanical properties of the thermoelectric material and the electrode can be secured.

The filling material is a material filling the void space of the thermoelectric material column array and is strongly bonded to the electrode so that the flexible thermoelectric device can have a sufficient mechanical and physical properties. Particularly, since the thermoelectric device has a low thermal conductivity, The conversion efficiency can be improved. The filling material may be a flexible material, and it is preferably a material having low thermal conductivity with flexibility.

The filling material having such flexibility and low thermal conductivity may be formed from a curable polymer. The curable polymer may be a polymer containing a curable functional group (curing group), which means a polymer before being cured by being filled in an empty space formed by a thermoelectric material column array. The curing group of the curable polymer may be partially or completely cured A filling material can be formed. That is, the polymer in the initial state before or after being filled in the thermoelectric material column array is referred to as a curable polymer, and the cured polymer is referred to as a filling material (or a polymer compound).

The filling material (or the polymer compound) is not particularly limited as long as it has flexibility and low thermal conductivity. Specifically, for example, the polymer compound may have a thermal conductivity of 0.1 W / mK or less, It is preferable to use a thermoelectric material having a thermal conductivity of 0.05 W / mK or less of thermal conductivity to effectively block heat transfer to secure thermal stability. In this case, the weight average molecular weight of the curable polymer may be 100 to 500,000 g / mol, and more preferably 5,000 to 100,000 g / mol.

The curable polymer is not particularly limited, but may be a thermosetting polymer, a photocurable polymer or a chemically curable polymer, and may be a chemically curable polymer in terms of uniform and fast curing.

The curable polymer is not particularly limited as long as it has flexibility after curing and has a low thermal conductivity, but may be specifically exemplified by a silicone polymer, an olefin elastic polymer or a polyurethane compound.

The silicone-based polymer, the olefin-based elastic polymer, or the polyurethane-based compound has high flexibility and elasticity after curing, has little change in physical properties with temperature, maintains flexibility in a wide temperature range and is easy to physically deform the thermoelectric element when applied to a flexible thermoelectric device , And it is not easily damaged by frequent physical deformation, thereby improving lifetime characteristics. In addition, since the silicone-based polymer and the olefin-based elastic polymer have low thermal conductivity, the diffusion of heat can be effectively prevented and the thermoelectric efficiency can be improved. Particularly, when the curable polymer is a silicone-based polymer, the bonding strength with the electrode is further improved and the physical stability of the thermoelectric device can be improved. The silicone-based polymer may be a condensation-type silicone-based polymer or an addition-type silicone-based polymer. The condensation type silicone polymer may undergo cross-linking curing by the hydrolysis and condensation reaction in the presence of water, and the addition type silicone polymer may undergo cross-linking curing by the addition reaction between the unsaturated group of the silicone type polymer and the cross-linking agent in the presence of the catalyst. In one non-limiting embodiment, the condensed silicone-based polymer is a polysiloxane having two or more hydroxyl groups, an aliphatic polysiloxane, an aromatic polysiloxane, or a siloxane repeating unit containing an aliphatic group and an aromatic group in one repeating unit, .

In one non-limiting embodiment, the aliphatic polysiloxane is selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polydimethylsiloxane-co-di Ethylsiloxane, polydimethylsiloxane-co-ethylmethylsiloxane, and the like. The aromatic polysalic acid may be selected from the group consisting of polydiphenylsiloxane, polymethylphenylsiloxane, poly Ethylphenylsiloxane, poly (dimethylsiloxane-co-diphenylsiloxane), and the like. The polysiloxane containing a siloxane repeating unit containing both aliphatic groups and aromatic groups in one repeating unit or independently includes repeating units of the exemplified aliphatic siloxane and repeating units of the aromatic siloxane, But the present invention is not limited thereto. The term " aromatic substituent "

The crosslinking agent (curing agent) may be appropriately selected depending on the type of the curable polymer. When the curable polymer is a silicone-based polymer, a siloxane-based curing agent containing Si-O bonds, an organosilazane containing Si- A curing agent, and a siloxane-based compound containing a Si-H bond. However, the present invention is not limited thereto.

The olefinic elastomeric polymer can be crosslinked and cured by the olefinic elastomeric polymer and the crosslinking agent to form a polymer compound. The olefinic elastomeric polymer can be, but is not limited to, poly (ethylene-co-alpha-olefin), ethylene propylene diene monomer rubber (EPDM rubber), polyisoprene or polybutadiene and the like as a non-limiting example. In this case, the crosslinking agent may be a vulcanizing agent, and is not limited as long as it is commonly used in the art. As a non-limiting example, sulfur or an organic peroxide may be used.

The polyurethane-based compound has a first form in which a polymer compound is formed by an addition condensation reaction of an isocyanate group (-NCO) and a hydroxyl group (-OH) in the presence of a catalyst, a polyurethane prepolymer containing an unsaturated group, And a second type in which a polymer compound is formed by an addition reaction between the two groups. However, the polyurethane-based compound referred to in the present invention is a material before being processed into a polyurethane (fill material), which is an initial-state first-type compound filled or filled in a thermoelectric material column array, or a polyurethane- Lt; / RTI >

In the first embodiment, a polymer compound can be formed by the reaction of a polyfunctional isocyanate compound containing two or more isocyanate groups and a polyol compound containing two or more hydroxy groups. The polyfunctional isocyanate compound may include, but not limited to, 4,4'-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), 1,4-diisocyanatobenzene (PPDI), 2 , 4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-bitolylene-4,4'-diisocyanate, 1,3-xylene diisocyanate, p- Isocyanate (p-TMXDI), 1,6-diisocyanato-2,4,4-trimethylhexane, hexamethylene diisocyanate (HMDI) 1,4-cyclohexane diisocyanate (CHDI), isophorone diisocyanate ) Or 4,4'-dicyclohexylmethane diisocyanate (H12MDI), but the present invention is not limited thereto. The polyol compound may be divided into a polyester polyol and a polyether polyol. The polyester polyol can be, in one non-limiting example, polyethylene adipate, polybutylene adipate, poly (1,6-hexadipate), polydiethylene adipate or poly (e-caprolactone) The polyether polyol can be, but is not limited to, polyethylene glycol, polydiethylene glycol, polytetramethylene glycol, polyethylene propylene glycol, and the like in one non-limiting example. In this case, the catalyst is not particularly limited as long as it is commonly used in the art, but an amine catalyst can be used. As a non-limiting example, dimethylcyclohexylamine (DMCHM), tetramethylenediamine (TMHDA), pentamethylene Diethylenediamine (PMEDETA) or tetraethylenediamine (TEDA) may be used.

In the second mode, a polymer compound can be formed by an addition reaction between a polyurethane-based prepolymer containing an ethylenic unsaturated group and a crosslinking agent. Such a polyurethane prepolymer may vary in the structure depending on the kind of the isocyanate group-containing compound and the polyol-based compound, but may be an ethylenic unsaturated group, more specifically, a polyurethane-based prepolymer containing a vinyl group. As a specific example, the vinyl group may be contained in 2 to 20 groups in one polyurethane chain, but not limited thereto. As the molecular weight of the polyurethane increases, vinyl groups may increase proportionally to more than 20, and polyurethane , The preferable range may include 2 to 4. In this case, the crosslinking agent may be a vulcanizing agent, and is not limited as long as it is commonly used in the art. As a non-limiting example, sulfur or an organic peroxide may be used.

The content of the curable polymer and the crosslinking agent can be selected in consideration of the degree of curing of the polymer compound. Specifically, the content of the crosslinking agent may be 1 to 100 parts by weight, preferably 3 to 50 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the curable polymer, Lt; / RTI > When the curable polymer further contains a catalyst known to promote curing, the content of the catalyst may be 0.001 to 5 parts by weight based on 100 parts by weight of the curable polymer, And can not be limited by the content of the substance or the catalyst.

The filling step of the fill material can include filling the fill material precursor (e.g., the curable polymer, as described above) into the void space formed by the thermoelectric material column array and curing the filled fill material precursor . Further, after the formation of the filling material, it is preferable to remove the filling material remaining in the unnecessary portion other than the empty space.

In an embodiment according to the present invention, the filling material precursor is not limited as long as it can be filled with the gap between the N-type thermoelectric material and the P-type thermoelectric material. For example, the material containing the curing polymer and the curing agent The liquid fill material precursor is filled in the substrate on which the electrode and the thermoelectric material column array are formed by capillary phenomenon or the liquid fill material precursor material including the hardenable polymer and the curing agent is filled in the electrode and thermoelectric material column array It is possible to immerse and fill the substrate.

The step of curing the filling material precursor filled in the void space formed by the thermoelectric column array includes not only the curing of the curable polymer but also the change to the solid phase as the solvent is volatilized and removed from the polymer material dissolved in the solvent .

As described above, the precursor of the filler material may include a curable polymer. If the curable polymer itself is a liquid, the drying process may be omitted. However, in the case of a solution phase dissolved in a solvent, .

 The drying process according to one example can be performed by drying at a temperature at which the solvent can be sufficiently blown for a predetermined time. In one embodiment, when the curable polymer is polydimethylsiloxane, the drying temperature may be from room temperature to 150 ° C, and the drying time may be from 10 minutes to 24 hours.

The curing process may vary depending on the type and content of the curable polymer and the curing agent. For example, in the case of a thermosetting functional group, the curing process can be performed by controlling the content of the thermosetting agent, the curing temperature and the curing time, Can be performed differently depending on the kind. As another example, in the case of a photocurable functional group, the curing process can be performed by adjusting the content of the photocuring agent, the amount of light, and the light intensity, but this may also be performed depending on the type of the photocurable functional group.

2 is a cross-sectional view of a structure (a flexible thermoelectric element structure) for thermoelectric element fabrication according to an embodiment of the present invention. As shown in FIG. 2, the structure includes a thermoelectric material 230 and 240 columnar array including at least one N-type thermoelectric material 230 and a P-type thermoelectric material 240 spaced from each other, A flexible thermoelectric element 200 comprising an electrode 220 electrically connecting thermoelectric materials 230 and 240 of the array and a fill material 250 filling at least the void spaces of thermoelectric materials 230 and 240, Two transparent substrates 110 spaced apart from each other and sandwiching the flexible thermoelectric element 200 therebetween; The buffer layer 121 is disposed between the flexible thermoelectric element 200 and the two transparent substrates 110 and the buffer layer 121 and the semiconductor layer 122 are laminated on the transparent thermoelectric element 200, And a sacrificial layer 120 in contact with the transparent substrate 110, the semiconductor layer 122 being in contact with the transparent substrate 110.

After providing the flexible thermoelectric element structure as shown in FIG. 2 through the above-described manufacturing method, the transparent substrate (the first transparent substrate and the second transparent substrate) of the flexible thermoelectric element structure is separated Can be removed.

Thereafter, a step of removing the semiconductor material (due to the semiconductor layer) and the buffer layer material remaining on the surface of the flexible thermoelectric element obtained by separating the transparent substrate may be performed. The removal of the semiconductor material and the buffer layer material may be performed by etching, and the etching is not particularly limited, but may be performed by a wet etching method or a physicochemical polishing method in which a semiconductor material or a buffer layer material is dissolved and removed. Since the flexible thermoelectric element from which the transparent substrate is removed has a very flexible characteristic, it is better to remove the residual material (the semiconductor material and the buffer layer material) by the wet etching method, and the wet etching etchant is appropriately selected Of course. As a specific and non-limiting example, an etchant containing nitric acid, hydrofluoric acid, or hydrofluoric acid can be used. However, it is needless to say that the present invention can not be limited by the material or composition of the etchant for removing residual materials.

 Since the flexible thermoelectric device manufactured according to an embodiment of the present invention does not have a mesh type support across the thermoelectric material or a support for supporting the electrode and the thermoelectric material outside the electrode, the thermoelectric material column can be highly integrated And is highly suitable for applications where high flexibility, physical stability, and strength are repeatedly caused by a high degree of warping, can be made lighter, and can have improved heat-electricity conversion efficiency.

After depositing a quartz substrate in a deposition chamber, a 50 nm amorphous silicon layer was formed at 300 ° C and a pressure of 2 torr using a mixed gas of SiH ₄ , H _2, and He, and SiH ₄ and N ₂ O A first sacrificial layer was prepared by depositing a 1.1 μm thick silicon oxide film on the amorphous silicon layer at a temperature of 400 ° C. and a pressure of 2.8 torr. Then, a copper paste composed of 2.4 wt% of glass frit, 2.3 wt% of nitrocellulose as a binder, 20.3 wt% of a vehicle and 75 wt% of copper was applied to the silicon oxide film of the first sacrificial layer in a predetermined pattern, (10 ^-2 torr or less) at 720 ° C for 20 minutes to prepare a first electrode. Similarly, another quartz substrate was formed as a second transparent substrate, a second sacrificial layer was formed in the same manner as the first substrate, the same copper paste was applied on the second sacrificial layer in a predetermined pattern, Electrode.

An N type thermoelectric material was formed on a separate support (quartz substrate) in the form of a round cylinder having a diameter of 2 mm and a thickness of 670 μm. Specifically, the glass frit 2.7 wt%, the binder is nitrocellulose 2.1% by weight, and the vehicle 10.7% by weight, and N-type thermoelectric after the N-type thermoelectric material paste made of a material 84.5% by weight of printing to the set area of the support, in an inert atmosphere (N ₂ , 110 torr) at 510 DEG C for 60 minutes to prepare an N-type thermoelectric material column array. Further, a P-type thermoelectric material was formed in the form of a round cylinder having a diameter of 2 mm and a thickness of 670 μm on another separate support (another quartz substrate). A P-type thermoelectric material paste having the same composition as that of the N-type thermoelectric material paste was printed on a predetermined area of the support, except that the P-type thermoelectric material was contained in place of the N-type thermoelectric material, and then an inert atmosphere (N ₂ , 110 torr) To 500 캜 for 60 minutes to fabricate a p - type thermoelectric column array.

A Sn _96.5 Ag ₃ Cu _0.5 paste was applied between the N-type thermoelectric material column array on the support and the first electrode of the first transparent substrate and heat treated in an inert gas atmosphere (N ₂ ) at 250 ° C for 1 minute, To prepare a first unit body. In the same manner, the P-type thermoelectric substance column array on another support was bonded and transferred to the second electrode to prepare a second unit body.

A silver paste is applied to one surface of a columnar n-type thermoelectric material in the first unit body and one surface of the cylindrical p-type thermoelectric material in the second unit body, and thereafter, The first unit and the second unit were bonded to each other so that the thermoelectric material and the P-type thermoelectric material were interlocked with each other, and then heat-treated at 250 ° C for 1 minute in an inert gas atmosphere (N ₂ ). The monomer units were combined and immersed in a filling liquid of polydimethylsiloxane prepolymer (prepolymer: DOW CORNING, SYLGARD 184 SILICONE ELASTOMER BASE, curing agent: DOW CORNING, SYLGARD 184 SILICONE ELASTOMER CURING AGENT, prepolymer: curing agent mixing ratio = 10: And then heat-treated at 90 ° C for 30 minutes to prepare a flexible thermoelectric device structure filled with polydimethylsiloxane.

The transparent substrate was peeled off by irradiating XeCl excimer laser (308 nm, 20 Hz) according to the method described above with reference to FIG. 1 toward the transparent substrate of the fabricated flexible thermoelectric device structure. At this time, the size of the square spot of the laser spot was 1.2 mm x 1.2 mm, and the travel distance (x axis or y axis) of the laser was 600 m. The laser power (P ₀ ) at the time of one irradiation was 700 mJ / cm ² .

After the separation of the transparent substrate (QUALTZ substrate), an etching solution in which nitric acid, hydrogen fluoride and water were mixed at a weight ratio of 10:15:75 and an etching solution in which hydrogen fluoride and water were mixed at a weight ratio of 1:10, Silicon oxide and silicon oxide (buffer layer) were removed to prepare a flexible thermoelectric device.

FIG. 3 is an optical photograph of a flexible thermoelectric device manufactured according to an embodiment of the present invention. FIG. 4 is a graph showing power per unit area and power per mass according to a thermal gradient of the manufactured flexible thermoelectric device, It has an extremely high power generation efficiency of 4.78 mW / cm ² and 20.3 mW / g. FIG. 5 is a graph of a resistance change after bending test of a flexible thermoelectric element manufactured according to an embodiment of the present invention and an optical photograph during a bending test (FIGS. 5A and 5B and FIGS. 6A and 6B 'Quot; means the direction shown in the optical photograph of Fig. 5). As shown in FIG. 5, it has excellent flexibility, physical and electrical stability, and physical and electrical characteristics are stably maintained even if a bending test of 5 mm is performed. FIG. 6 is a graph showing changes in electrical characteristics at the time of repetitive bending test. As can be seen from FIG. 6, even when 10000 repetitive bending is performed with a curvature of 30 mm, the resistance change rate is 15% or less. As a result, it can be seen that the electrical characteristics of the flexible thermoelectric device are kept extremely stable even in repetitive physical deformation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (16)

delete a) flexible thermoelectric elements; Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And a semiconductor layer disposed between the flexible thermoelectric element and the two transparent substrates, the buffer layer being an insulating layer and the semiconductor layer being a mixed phase of amorphous, crystalline or amorphous and crystalline, and the buffer layer being in contact with the flexible thermoelectric element, Providing a flexible thermoelectric element structure including a sacrificial layer having a layer in contact with the transparent substrate; And
b) separating the transparent substrate by irradiating a laser to the semiconductor layer through the transparent substrate and irradiating a laser satisfying Relation 1 to allow the semiconductor material of the semiconductor layer to crystallize or recrystallize, ≪ / RTI >
(Relational expression 1)
100 mJ / cm ² ? P _l ? 5J / cm ²
(In the relational expression 1, Pl is the laser power irradiated on the semiconductor layer) 3. The method of claim 2,
Wherein the laser is irradiated twice or more so that the accumulated laser power of the irradiated laser satisfies the relational expression (1) in the step (b). 3. The method of claim 2,
In the step b), a spot or a line is formed on the basis of the first direction and the second direction orthogonal to each other in-plane with the interface between the semiconductor layer and the transparent substrate as a reference plane, The moving distance of the center of the spot or the center line of the line when moving in the first direction or the second direction is smaller than the width of the spot or the width of the line A method of manufacturing a flexible thermoelectric device. 5. The method of claim 4,
Satisfies the following relational expression (2) when the movement of the laser beam is irradiated.
(Relational expression 2)
0.2R ₀ ? D _l ? 0.8R ₀
(In the equation 2, D1 is the laser movement distance of the center of the center or line of spots in the first direction or the second direction, R ₀ is the width of the laser line width or of the laser spot) 3. The method of claim 2,
Wherein the laser has a center wavelength of 150 to 400 nm. The method according to claim 6,
Wherein the laser is selected from one or more of ArF laser, KrF laser, XeCl laser, XeF laser and KrCl laser. 3. The method of claim 2,
Wherein the semiconductor layer is dehydrogenated by heat treatment. 3. The method of claim 2,
Wherein the buffer layer has a thermal conductivity of 0.01 to 300 (Wm ^-1 K ^-1 ). 3. The method of claim 2,
Wherein the thickness of the semiconductor layer is 10 nm to 1 占 퐉. 3. The method of claim 2,
Wherein the thickness of the buffer layer is 0.5 to 5 占 퐉. 3. The method of claim 2,
Wherein the buffer layer is an oxide or a nitride. 3. The method of claim 2,
Wherein the semiconductor material of the semiconductor layer is a quaternary semiconductor including silicon (Si), germanium (Ge), or silicon germanium (SiGe); Group 3-5 semiconductors including gallium arsenide (GaAs), indium phosphide (InP), or gallium phosphide (GaP); Group 2-6 semiconductors including cadmium sulfide (CdS) or zinc telluride (ZnTe); And lead sulfide (PbS). 4. The method according to claim 1, 3. The method of claim 2,
The step a)
a1) a thermoelectric material column array including at least one N-type thermoelectric material and a P-type thermoelectric material arranged apart from each other, a first electrode coupled to one end of the thermoelectric material column array, and a first sacrificial layer disposed under the first electrode, And a second transparent substrate having a first transparent substrate formed thereon, a second electrode coupled to the other end of the thermoelectric material column array, and a second sacrificial layer disposed over the second electrode, step; And
and a2) forming a filling material in a vacant space of the thermoelectric material column array. 3. The method of claim 2,
After step b)
Etching the buffer material of the buffer layer remaining in the flexible thermoelectric element and the semiconductor material caused by the semiconductor layer. A thermoelectric material column array comprising at least one N-type thermoelectric material and a P-type thermoelectric material spaced apart from each other, an electrode electrically connecting the thermoelectric material of the thermoelectric material column array, and at least an empty space of the thermoelectric material column array A flexible thermoelectric device including a filling material to be filled;
Two transparent substrates facing each other with the flexible thermoelectric element interposed therebetween; And
The buffer layer is in contact with the flexible thermoelectric element, and the buffer layer is disposed between the transparent thermoelectric element and the transparent substrate. The buffer layer is a laminated layer of amorphous, crystalline or amorphous and crystalline mixed layers. And a sacrificial layer in contact with the transparent substrate,
Wherein the filling material is a silicone-based polymer, an olefin-based elastic polymer, or a polyurethane-
Wherein the semiconductor material of the semiconductor layer is crystallized or recrystallized by a laser beam irradiated to the semiconductor layer through the transparent substrate, and the transparent substrate is separated to produce a flexible thermoelectric device.

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