KR20210118647A - Method of manufacturing antimony selenide thin film solar cell - Google Patents

Abstract

The present invention provided a method for manufacturing an antimony-selenide thin film solar cell that comprises the steps of: forming an antimony (Sb) metal precursor layer on the rear electrode of a substrate coated with a rear electrode; and selenizing the antimony metal precursor layer in a selenium (Se) vapor atmosphere to form an antimony selenide (Sb2Se3) light absorbing layer.

Description

Method of manufacturing antimony selenide thin film solar cell

The present invention relates to a method of manufacturing a thin film solar cell, and more particularly, to a method of manufacturing an antimony selenide thin film solar cell including a method of forming an _{antimony selenide (Sb 2} Se _{3 ) light absorption layer.}

Solar cell technology has recently been attracting attention as an eco-friendly renewable energy technology to solve serious environmental pollution problems and problems caused by fossil energy depletion. The solar cell is expected as an energy source capable of solving future energy problems because it has low pollution, infinite resources, and a semi-permanent lifespan.

In general, solar cells based on semiconductor materials operate on the principle of directly converting sunlight into electricity using the photovoltaic effect, which generates electrons when light is irradiated to a semiconductor diode forming a pn junction. , a back electrode and a light absorbing layer positioned between them.

Among them, the most important material is a light absorbing layer that determines most of the light conversion efficiency, and may be classified into various types depending on a material used as the light absorbing layer. Currently, the most used is a silicon solar cell using silicon. However, interest in thin-film solar cells is increasing as prices have surged due to a recent lack of supply of silicon, and since the thin-film solar cells are manufactured with a thin thickness, the material consumption is small and the weight is light, so the application range is wide.

Copper indium gallium selenide (CIGS), which has a high light absorption coefficient, is in the spotlight as a material for such a thin film solar cell.

The CIGS solar cell is composed of four elements: copper (Cu), indium (In), gallium (Ga), and selenium (Se), and has a thickness of 1 μm to 2 μm due to a high light absorption coefficient of ^{10 5} cm ^{-1 or more.} It is possible to manufacture a high-efficiency solar cell only with the light absorption layer of Since it is complex and uses four elements at the same time, composition control is difficult.

_{Antimony selenide (Sb 2} Se ₃ ), one of the materials of thin film solar cells, is a simple two-component compound semiconductor. one

The antimony selenide has unique material properties such as optoelectronic excellent physical properties, a stable single crystalline phase, and a unique layered structure with loose bonds, and many researchers recently I am interested in the development of solar cell technology.

1 is a schematic diagram of the structure of an antimony-selenide thin film solar cell.

Referring to FIG. 1, the structure of the antimony-selenide thin film solar cell has five units of thin film on a substrate, that is, a back electrode (Mo, etc.), an antimony selenide light absorption layer that is a p-type light absorption layer, and an n-type buffer layer (CdS). etc.), a transparent electrode (ZnO, etc.), and a front electrode (Ni/Ag, etc.) are sequentially stacked.

Antimony (Sb) and selenium (Se), which are constituent elements of the antimony-selenide light absorbing layer, are elements abundant in nature and do not cause significant environmental problems, and the maximum photoelectric conversion efficiency has been reported to be 9.2% so far.

An efficient method for manufacturing an antimony-selenide light absorbing layer, which is a core component of the antimony-selenide thin film solar cell, is required.

Republic of Korea Patent No. 10-1403462

One object of the present invention is to provide a method for manufacturing an antimony-selenide thin film solar cell.

Another object of the present invention is to provide an antimony selenide thin film solar cell manufactured by using the above manufacturing method.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. There will be.

One aspect of the present invention comprises the steps of forming an antimony metal precursor layer on the rear electrode of the substrate coated with the rear electrode; and selenizing the antimony metal precursor layer in a selenium vapor atmosphere to form an antimony selenide (Sb ₂ Se ₃ ) light absorption layer; It provides a method of manufacturing an antimony selenide thin film solar cell comprising a.

In one embodiment of the present invention, the step of forming the antimony metal precursor layer may be performed by any one of a vacuum deposition method, sputtering, chemical vapor deposition, thermal decomposition, and CBD method.

In an embodiment of the present invention, the forming of the antimony selenide light absorption layer may be performed using molecular beam epitaxy (MBE).

In an embodiment of the present invention, the forming of the antimony-selenide light absorption layer includes: disposing a Knudsen cell on which a substrate and a selenium supported with an antimony metal precursor layer are formed in a chamber; heating the substrate to a reaction temperature, heating the Knudsen cell during the heating to increase the temperature to evaporate the selenium, and depositing the evaporated selenium on the antimony metal precursor layer of the substrate; and maintaining and heating the substrate at a reaction temperature, heating the Knudsen cell during the maintenance heating to continuously supply evaporated selenium to the antimony metal precursor layer, and the deposited selenium and antimony react to react with antimony. and forming selenide.

In one embodiment of the present invention, the reaction temperature may be 300 ℃ to 500 ℃.

In an embodiment of the present invention, in the depositing step, the heating process of heating the substrate to a reaction temperature may be performed for 20 to 40 minutes.

In one embodiment of the present invention, the step of forming the antimony selenide may be performed for 5 to 20 minutes.

In an embodiment of the present invention, the forming of the antimony selenide light absorption layer may be performed at a pressure ^{of 10 -1} Torr to 10 ^{-3 Torr.}

In one embodiment of the present invention, after forming the antimony-selenide light absorption layer, forming a buffer layer on the antimony-selenide light absorption layer; forming a transparent electrode on the buffer layer; and forming a front electrode on the transparent electrode. may include.

One aspect of the present invention provides an antimony-selenide thin film solar cell manufactured by the above manufacturing method.

The present invention provides a method for manufacturing an antimony-selenide thin film solar cell that is efficient and has a shortened formation rate, including a method of forming an antimony-selenide light absorption layer using a two-step process, and uses the method for low cost, low toxicity, and It is possible to provide a stable inorganic thin film solar cell.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a schematic diagram of the structure of an antimony-selenide thin film solar cell.
2 and 3 are flowcharts of a method of manufacturing an antimony selenide thin film solar cell according to an embodiment of the present invention.
4 is a schematic diagram of a method of manufacturing an antimony selenide light absorbing layer according to an embodiment and a comparative example of the present invention.
5 is an SEM image of an SLG/Mo/Sb/Se structure of an experimental example of the present invention.
6 is a photograph of in-situ high-temperature X-ray diffraction (HT-XRD) of an experimental example of the present invention.
7 is a graph showing the results of HT-XRD of an experimental example of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

In this specification, when a part such as a layer, film, region, plate, etc. is "on" another part, it includes not only the case where it is directly on the other part, but also the case where there is another part in the middle.

It will be understood that when an element, such as a layer, region, or substrate, is referred to as being “on” another component, it may be directly on the other element or intervening elements in between. .

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

One aspect of the present invention provides a method of manufacturing an antimony selenide thin film solar cell.

1 is a schematic diagram of the structure of an antimony-selenide thin film solar cell, and FIGS. 2 and 3 are flowcharts of a method of manufacturing an antimony-selenide thin film solar cell of the present invention.

Referring to FIG. 2 , the method of manufacturing an antimony-selenide thin film solar cell of the present invention includes forming an antimony (Sb) metal precursor layer on a rear electrode of a substrate coated with a rear electrode (S10); Selenizing the antimony metal precursor layer in a selenium (Se) vapor atmosphere to form an antimony selenide (Sb ₂ Se ₃ ) light absorption layer (S20); forming a buffer layer on the antimony selenide light absorption layer (S30); forming a transparent electrode on the buffer layer (S40); and forming a front electrode on the transparent electrode (S50).

First, the method of manufacturing an antimony-selenide thin film solar cell of the present invention includes the step (S10) of forming an antimony (Sb) metal precursor layer on a rear electrode of a substrate coated with a rear electrode.

Referring to FIG. 1 , the structure of a typical antimony thin film solar cell may have a back electrode, a p-type light absorption layer, an antimony selenide light absorption layer, an n-type buffer layer, a transparent electrode, and a front electrode sequentially stacked on a substrate. .

The material of the substrate is not limited as long as it is obvious in the technical field of thin film solar cells. For example, the material of the substrate may be a ceramic substrate such as alumina, stainless steel, a metal substrate such as copper tape (Cu tape), a polymer substrate, or the like, or soda-lime glass (SLG). A glass substrate may be used. The soda-lime glass substrate is inexpensive compared to substrates of other materials, and sodium (Na) diffused from the soda-lime glass diffuses into the light absorption layer during the process to increase the charge concentration of the light absorption layer, or structurally according to the composition change. It can play a role in reducing the change in characteristics, thereby increasing the efficiency of the solar cell.

The material used for the rear electrode is not limited as long as it is obvious in the field of thin film solar cell technology. For example, the rear electrode may include any one of nickel (Ni), copper (Cu), and molybdenum (Mo), for example, molybdenum (Mo). The molybdenum has high electrical conductivity and is stable at high temperature in a selenium atmosphere.

In one embodiment of the present invention, the substrate is soda-lime glass, the back electrode may be made of molybdenum, for example, the back electrode made of molybdenum is sputtering on the surface of the soda-lime glass, It may be formed by any one of a thermal evaporation method, an E-beam evaporation method, and an electrodeposition method, and an antimony (Sb) metal is formed on the rear electrode of the substrate coated with the rear electrode. In the step of forming the precursor layer (S10), the substrate coated with the rear electrode may be molybdenum-coated soda-lime glass.

In one embodiment of the present invention, the method of forming the antimony selenide light absorbing layer of the present invention may use a two-step process.

In the present specification, the two-step process is also called a precursor-selenization process, and in a method of forming a CIGS light absorption layer of a CIGS thin film solar cell having a structure similar to that of an antimony selenide thin film solar cell, It corresponds to the method evaluated as the closest process to area commercialization.

The two-step process is performed by preparing the metal precursor in the first process, and then annealing the metal precursor at a high temperature in a selenium vapor atmosphere in the second process. For example, in the case of the formation of the CIGS light absorption layer, the two-step process prepares a Cu-Ga-In metal alloy or a precursor containing selenium in the first process, and hydrogen selenide (H ₂ Se) gas or The CIGS light absorption layer may be formed by annealing at a high temperature in a selenium (Se) vapor atmosphere.

The step (S10) of forming an antimony (Sb) metal precursor layer on the back electrode of the back electrode-coated substrate of the present invention may be a step corresponding to the first step of the two-step process.

For example, in the step (S10) of forming an antimony (Sb) metal precursor layer on the rear electrode of the substrate coated with the rear electrode, the substrate coated with the rear electrode may be molybdenum-coated soda-lime glass. and an antimony metal precursor layer may be formed on the molybdenum-coated surface of the molybdenum-coated soda-lime glass substrate.

The step of forming the antimony metal precursor layer (S10) is a step of depositing the antimony metal on the surface of the substrate coated with the back electrode, and includes vacuum evaporation, sputtering, and chemical vapor deposition. vapor deposition), thermal decomposition (spray pyrolysis), and CBD (chemical bath deposition) method, for example, it may be performed using a DC sputtering method.

The DC sputtering method is a sputtering method using a DC power source, and although the target is limited to metal, the structure is simple, the amount of current and the thickness of the thin film are almost in direct proportion, so it is easy to control, and the uniformity of the thin film is large. do.

For example, in the forming of the metal precursor layer ( S10 ), the DC sputtering process targeting antimony may be performed to form a structure in which a substrate, a rear electrode, and an antimony metal precursor layer are sequentially stacked.

In one embodiment of the present invention, before the step of forming the metal precursor layer (S10), the step of washing the substrate coated with the back electrode may be additionally performed.

The step of cleaning the substrate corresponds to a pretreatment process performed to facilitate deposition of the metal precursor layer in the step of forming the metal precursor layer (S10), which is performed thereafter, for example, acetone, menthol, and deionized water. It may be washed by using, but is not limited to.

Next, the manufacturing method of the antimony-selenide thin film solar cell of the present invention includes the step (S20) of forming an antimony-selenide light absorption layer by selenizing the metal precursor layer in a selenium vapor atmosphere.

The selenization process may be a step corresponding to the second process in the two-step process described above, and the metal precursor and selenium vapor come into contact with the reaction to occur, and corresponds to a process of generating a desired light absorption layer. The conventional selenization process was _{performed by heating hydrogen selenide (H 2} Se) gas or selenium (Se) vapor while flowing into a certain container or chamber in which a metal precursor was disposed to increase the temperature in the chamber. However, the selenization process performed in this way has the disadvantage that the hydrogen selenide gas used in the selenization process is toxic, and the selenization process time is long, which requires high cost in terms of safety facility construction and process time.

In the selenide process, the selenium vapor to a series of there is to include a ring, a massive chain Se _{x (x>} 5) in the Se ₈ to dimer Se ₂ high temperature thermal cracking or plasma cracking Se _x (x When it is transformed into <4) and evaporated, it is excellent in diffusion and reactivity, and thus the quality of the resulting thin film can be improved.

Therefore, in the production of the selenium vapor, there is a need to precisely control the selenium evaporation rate, and since the evaporation rate of selenium is determined by the vapor pressure according to the temperature, the evaporation rate of selenium is generally controlled by temperature. and flux control.

Forming the light absorption layer of the present invention (S20) is performed by selenizing the antimony metal precursor layer in a selenium vapor atmosphere, the selenization process may be performed using molecular beam epitaxy (MBE). .

The molecular beam epitaxy method can be performed using a Knudsen cell, which is useful for accurately controlling the evaporation rate and continuous temperature of selenium in the production of the above-described selenium vapor. can

In the present specification, molecular beam epitaxy (MBE) refers to a crystal growth method of epitaxial growth using molecular beam deposition in ultra-high vacuum, and is mainly used to form a compound single crystal film.

Molecular beam deposition refers to deposition using molecular beams, that is, a technique for vacuum deposition on a substrate by scattering evaporation molecules from an evaporation source so as not to collide with each other. This is basically the same as the conventional vacuum deposition method and the film growth mechanism, but the molecules of all component elements protruding from the evaporation source are incident on the substrate surface in a beam state, and the scattered molecules do not form a residual layer. Compared to other crystal growth methods, the MBE method can monitor and control both sides separately because the crystal growth part and the source of growth material are separated, and by opening and closing the shutter, the molecular beam can be instantaneously started and stopped. It is easy to precisely control the film thickness or to make a rapid composition change in the growth direction, and it is advantageous in that it is possible to observe the composition or surface structure of the film during crystal growth and control the properties of the precipitated film on the spot.

The Knudsen cell is a device composed of a crucible, a heating filament, and a water cooling system, and through an appropriate design including adjustment of the aspect ratio of the crucible, the evaporation of the source is uniform, and the emission of the vapor is in the form of a molecular beam It is designed so that it can be transferred well to the substrate. In addition, the Knudsen cell can be used to measure a very low vapor pressure by measuring the flux of the emitted vapor through a sensor, and further, it can be used as a source evaporator in the selenization process using the molecular beam epitaxy. By controlling the temperature using the heating filament, it is possible to finely control the evaporation rate of the source.

Referring specifically to FIG. 3, the step of forming the light absorption layer using the Knudsen cell and the MBE of the present invention (S20) is a Knudsen cell ( Placing Knudsen cells) (S21); heating the substrate to a reaction temperature, heating the Knudsen cell during the temperature increase heating to evaporate the selenium, and depositing the evaporated selenium on the antimony metal precursor layer of the substrate (S22); and maintaining and heating the substrate at a reaction temperature, heating the Knudsen cell during the maintenance heating to continuously supply evaporated selenium to the antimony metal precursor layer, and the deposited selenium and antimony react to react with antimony. and forming selenide (S23).

First, the step of forming the light absorption layer (S20) of the present invention includes the step of disposing the Knudsen cell on which the antimony metal precursor layer is formed and the selenium-supported substrate in the chamber (S21).

In the above step, the substrate on which the antimony metal precursor layer is formed and the Knudsen cell may be disposed to face each other, the selenium supported in the Knudsen cell may be in powder form or granular form, and the basic pressure of the chamber is 10 ⁻⁶ It can be set to Torr.

Next, in the step of forming the light absorption layer of the present invention (S20), the substrate is heated to a reaction temperature, the Knudsen cell is heated during the heating to increase the temperature to evaporate the selenium, and the evaporated selenium is the substrate. depositing on the antimony metal precursor layer (S22) and maintaining and heating the substrate to a reaction temperature, heating the Knudsen cell during the maintenance and heating to continuously supply evaporated selenium to the antimony metal precursor layer, and reacting the deposited selenium and antimony to form antimony selenide (S23).

In an embodiment of the present invention, the substrate and the Knusensel may each include a heating device, and each heating device may be used for heating.

In the step (S22) in which the evaporated selenium is deposited on the antimony metal precursor layer of the substrate and the deposited selenium and antimony are reacted to form antimony selenide (S23), the reaction temperature is 300 ℃ to It may be 500 °C, for example, 350 °C to 450 °C.

When the reaction temperature is less than 300 °C, the antimony selenide light absorption layer may not be formed, and when the reaction temperature is higher than 500 °C, antimony selenide may be decomposed.

The selenium is a metal having a melting point of about 220 ℃, and as the temperature rises, it can be crystallized at about 150 ℃ to 200 ℃, and at a temperature of about 200 ℃ or more, for example, 250 ℃, the crystallized selenium is melted to form a vapor can be changed to

For example, in the step (S22) in which the evaporated selenium is deposited on the antimony metal precursor layer of the substrate, the Knudsen cell is heated while the substrate is heated to the reaction temperature in the above range, so that the Knudsen cell is When the temperature reaches about 220 ° C. or higher, selenium supported in the Knudsen cell is evaporated and can start to be deposited on the antimony metal precursor layer having a temperature of about 220 ° C. or higher, and thereafter, until the temperature of the substrate reaches the reaction temperature The reaction between antimony and selenium does not occur, and only selenium in vapor form may be continuously deposited on the metal precursor layer.

In this case, the evaporation temperature of the selenium is according to an embodiment, and as the vacuum degree in the chamber increases, the evaporation temperature of the selenium may be lower than the above-described temperature (about 220 ℃).

In one embodiment of the present invention, in the depositing step (S22), the heating process to increase the temperature may be performed for 20 minutes to 40 minutes.

During the heating time to increase the temperature, the vapor form of selenium may be sufficiently deposited on the antimony metal precursor layer to correspond to an amount sufficient to react with antimony in a step to be described later.

Selenium and antimony deposited on the surface of the antimony metal precursor layer may be reacted at a temperature of about 300° C. or higher to form an antimony selenide (Sb ₂ Se ₃ ) binary phase. In addition, at a temperature of about 500° C. or higher, the antimony selenide may be decomposed to form an antimony metal phase.

For example, in the step (S23) of the deposited selenium and antimony reacting to form antimony selenide, when the temperature of the substrate reaches the reaction temperature, selenium deposited on the surface of the antimony metal precursor layer And antimony may react to generate antimony selenide. When the substrate reaches the reaction temperature, the temperature of the substrate is maintained and heated, and the selenium supported in the Knudsen cell is heated while the temperature of the substrate is maintained and heated. By continuously generating selenium vapor at a temperature above the melting point of selenium, it may be supplied to the antimony metal precursor layer.

The selenization process in an embodiment of the present invention has a mechanism in which selenium in vapor form is deposited and contacted with the antimony precursor layer, and then the selenium and the antimony metal react to form antimony selenide, The reaction temperature of selenium and antimony is 300 °C to 500 °C.

However, in the step of depositing the evaporated selenium on the antimony metal precursor layer of the substrate (S22) and the step of reacting the deposited selenium and antimony with antimony to form antimony selenide (S23), Antimony selenide may not be generated depending on the method of controlling the temperature of the substrate and the Knudsen cell.

For example, i) heating the Knudsen cell to generate selenium vapor and depositing it on the metal precursor layer of the substrate, and then heating the substrate to the reaction temperature, or ii) heating the temperature of the substrate to the reaction temperature , when the Knudsen cell is heated to generate selenium vapor and deposited on the metal precursor layer of the substrate heated to the reaction temperature, sufficient antimony selenide may not be generated.

In the case of i), selenium evaporated and deposited on the antimony metal precursor layer because the temperature of the substrate is not sufficient is removed before the temperature of the substrate reaches the reaction temperature and reacts with antimony to form antimony selenide. There may not be enough selenium left in the antimony metal precursor layer to produce, and given that the melting point of selenium in case ii) is about 220° C., the temperature of the substrate is already above the melting point of selenium. temperature, there may not be enough selenium remaining in the antimony metal precursor layer to evaporate to form antimony selenide before being deposited on the antimony metal precursor layer.

Therefore, the present invention heats the substrate to a reaction temperature, heats the Knudsen cell during the heating to evaporate the selenium, and deposits the evaporated selenium on the antimony metal precursor layer of the substrate (S22). ); and maintaining and heating the substrate at a reaction temperature, heating the Knudsen cell during the maintenance heating to continuously supply evaporated selenium to the antimony metal precursor layer, and the deposited selenium and antimony react to react with antimony. By performing the step of forming selenide (S23), it is possible to efficiently form the antimony selenide light absorption layer.

In an embodiment of the present invention, in the step of depositing the evaporated selenium on the antimony metal precursor layer of the substrate (S22) and the step of reacting the deposited selenium and antimony to form antimony selenide (S23) The working pressure may be 10 ⁻¹ Torr to 10 ⁻³ Torr, and the step of forming the antimony selenide (S23) may be performed for 5 to 20 minutes.

Conventional selenization process has the disadvantage that a long process time requires high cost, but the selenization process of the present invention has the advantage that the time is shortened.

The method for manufacturing an antimony-selenide thin film solar cell of the present invention includes: after forming an antimony-selenide light-absorbing layer (S20), forming a buffer layer on the antimony-selenide light-absorbing layer (S30); forming a transparent electrode on the buffer layer (S40); and forming a front electrode on the transparent electrode (S50).

The step of forming the buffer layer (S30) to the step of forming the front electrode (S50) may be performed using materials and methods well known in the art of inorganic thin film solar cells, and the present invention is not limited thereto.

For example, in one embodiment of the present invention, the buffer layer is ZnS, Zn(S,O), Zn(OH,S), ZnS(O,OH), ZnSe, ZnInS, ZnInSe, ZnMgO, Zn(Se, OH), ZnSnO, ZnO, CdS, CdZnS, InSe, InOH, In(OH,S), In(OOH,S), In(S,O) Step S30 is a solution growth method (CBD), an electrodeposition method (Electrodeposition), a coevaporation method (Coevaporation), a sputtering method (Sputtering), an atomic layer growth method (Atomic Layer Epitaxy), an atomic layer deposition method (Atomic Layer Deposition), chemical At least one of vapor deposition (CVD), organometallic chemical vapor deposition (MOCVD), molecular beam growth (MBE), spray pyrolysis, ILGAR (Ion Layer Gas Reaction), and pulsed laser deposition method can be carried out.

For example, in an embodiment of the present invention, the transparent electrode may be formed on the buffer layer using a radio frequency magnetron sputtering method. For the transparent electrode, for example, a ZnO thin film doped with Al (hereinafter, ZnO:Al thin film) may be used. For deposition of the transparent electrode, RF magnetron sputtering is mainly used, but in some cases, DC, reactive sputtering, organic metal chemical vapor deposition, etc. may be used.

For example, in one embodiment of the present invention, the front electrode is at least one of zinc oxide, gallium oxide, aluminum oxide, indium oxide, lead oxide, copper oxide, titanium oxide, tin oxide, iron oxide, tin dioxide, and indium tin oxide. Consists of including any one, and the step of forming the front electrode (S50) is RF sputtering method, reactive sputtering method, evaporation method (Evaporation), electron beam evaporation method (E-beam evaporation), metal organometallic chemical vapor deposition (MOCVD), An atomic layer epitaxy (Atomic Layer Epitaxy) method, an atomic layer deposition method (Atomic Layer Deposition), molecular beam growth method (MBE), it may be carried out using any one method of the electrodeposition method (Electrodeposition).

One aspect of the present invention provides an antimony-selenide thin film solar cell manufactured by the method of manufacturing the antimony-selenide thin film solar cell described in the above-described aspect.

Referring to FIG. 1 , the antimony-selenide thin film solar cell of the present invention may include a substrate, a rear electrode, an antimony-selenide light absorption layer, a buffer layer, a transparent electrode, and a front electrode.

The description of the substrate, the rear electrode, the antimony selenide light absorption layer, the buffer layer, the transparent electrode, and the front electrode is replaced with that described in the above embodiment.

The present invention can provide an antimony selenide thin film solar cell with improved stability and low cost, low toxicity.

Example

Example 1. Preparation of antimony selenide light absorbing layer

1.1 Cleaning the substrate

Soda-lime glass (SLG) substrate coated with molybdenum (Mo) was treated with acetone (99.8%, DUKSAN PURE CHEMICALS, Korea), menthol (99.8%, DUKSAN REAGENTS, Korea) and Smart ROB (Heal Force Bio- It was sequentially washed with deionized water (DI water) prepared using meditech Holdings Limited, China), and dried with nitrogen gas for 30 minutes.

1.2 Formation of Antimony Metal Precursor Layer

The substrate cleaned in 1.1 and an antimony target of 99.999% purity (diameter = 10.6 cm, thickness = 0.635 icm, iTASCO, Korea) were initially loaded into the sputtering chamber so that the distance between the target and the substrate was 10 cm.

The sputtering chamber ^{was evacuated to a base pressure of 1.33 X 10 -4} Pa, and 25 sccm through a mass flow controller (model: URS-100-5 MFC controller, Unit Instruments, USA) to maintain an inert atmosphere/working pressure of 0.67 Pa. Argon gas was introduced into the sputtering chamber, and DC power of 150 W was applied to the antimony target.

The antimony target was pre-sputtered for 10 min to remove surface contamination, and an antimony metal precursor layer was deposited at 4 rpm for 5 min.

1.3 Formation of antimony selenide light absorption layer

Selenium vapor by placing the substrate on which the antimony metal precursor layer prepared in 1.2 is deposited and the Knussen cell including the selenium powder in the MBE chamber, and heating the substrate to 400 °C while simultaneously heating the Knudsen cell to 300 °C was produced, selenium vapor was deposited on the antimony metal precursor layer during elevated temperature, and ^{annealed at a constant temperature of 400 ° C. and a pressure of 10 -2} Torr for 10 minutes to form an antimony selenide light absorption layer.

4 is a schematic diagram of Example 1, and in the case of Example 1, it was confirmed that an antimony selenide light absorbing layer was formed.

Comparative Example 1

In Example 1, instead of the process of Example 1.3, the Knudsen cell was first heated to generate selenium vapor, deposited on the antimony metal precursor layer, and the substrate was heated to 400 ° C. An antimony selenide light absorption layer was formed in the same manner as in Example 1.

4 is a schematic diagram of Comparative Example 1, and in Comparative Example 1, it was confirmed that the antimony selenide light absorbing layer was not formed.

Comparative Example 2

In Example 1, instead of the process of Example 1.3, the substrate was first heated to 400° C., and the Knudsen cell was heated later to generate selenium vapor and deposit the antimony metal precursor layer on the antimony metal precursor layer. Then, in the same manner as in Example 1, an antimony selenide light absorption layer was formed.

4 is a schematic diagram of Comparative Example 2, and in Comparative Example 2, it was confirmed that the antimony selenide light absorbing layer was not formed.

Experimental Example 1. Selection of optimal selenization process temperature

In order to confirm whether the antimony-selenide light absorbing layer of Example 1 was generated, an experiment was conducted to study the reaction mechanism between antimony and selenium.

Antimony (Sb) is deposited on a molybdenum (Mo)-coated soda-lime glass (SLG) substrate through sputter deposition, and selenium (Se) is evaporated thereon to form a precursor having the same structure as SLG/Mo/Sb/Se. generated (Fig. 5).

Using the in-situ high-temperature X-ray diffraction (HT-XRD) shown in FIG. 6 , the SLG/Mo/Sb/Se precursor was heated at a temperature increase rate of 20 °C/min in a selenium vapor atmosphere. The selenization reaction mechanism of antimony was analyzed by observing the change of the crystal phase according to temperature by performing XRD analysis every 50 °C, and the results are shown in FIG. 7 .

7, the peak corresponding to antimony was not found in the initial room temperature state, so it could be determined that it was not a crystalline phase, and in the case of selenium deposited in the initial precursor, 2θ = 23 ° to 24 ° weak From the fact that the peak was found, it could be determined that it was amorphous with insufficient crystallinity.

Then, as the temperature increased, selenium was crystallized at about 150 ℃ to 200 ℃, and then the XRD peak disappeared as the crystal was melted at about 250 ℃, and from about 300 ℃, antimony selenide (Sb ₂ Se ₃ ) binary phase It was confirmed that the antimony metal phase was detected as antimony selenide was rather decomposed from about 500 °C.

Therefore, it could be expected that the optimum reaction temperature of antimony selenide should be selected as high as possible in the range of about 350 °C to 450 °C.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (10)

forming an antimony metal precursor layer on the rear electrode of the substrate coated with the rear electrode; and
Selenizing the antimony metal precursor layer in a selenium vapor atmosphere to form an antimony selenide (Sb ₂ Se ₃ ) light absorption layer;
A method of manufacturing an antimony selenide thin film solar cell comprising a. The method of claim 1,
The step of forming the antimony metal precursor layer is a method of manufacturing an antimony-selenide thin film solar cell, characterized in that it is performed by any one of a vacuum deposition method, sputtering, chemical vapor deposition, thermal decomposition, and CBD method. The method of claim 1,
The forming of the antimony-selenide light absorption layer is a method of manufacturing an antimony-selenide thin film solar cell, characterized in that it is performed using molecular beam epitaxy (MBE). The method of claim 1,
The step of forming the antimony selenide light absorption layer,
disposing a substrate on which an antimony metal precursor layer is formed and a Knudsen cell on which selenium is supported in the chamber;
heating the substrate to a reaction temperature, heating the Knudsen cell during the heating to increase the temperature to evaporate the selenium, and depositing the evaporated selenium on the antimony metal precursor layer of the substrate; and
The substrate is maintained and heated to a reaction temperature, and selenium evaporated by heating the Knudsen cell during the maintenance heating is continuously supplied to the antimony metal precursor layer, and the deposited selenium and antimony react to react with antimony selenium. forming nides;
A method of manufacturing an antimony-selenide thin film solar cell comprising a. 5. The method of claim 4,
The reaction temperature is a method of manufacturing an antimony selenide thin film solar cell, characterized in that 300 ℃ to 500 ℃. 5. The method of claim 4,
In the deposition step,
The method of manufacturing an antimony-selenide thin film solar cell, characterized in that the step of heating the substrate to the reaction temperature is performed for 20 to 40 minutes. 5. The method of claim 4,
The method of manufacturing an antimony-selenide thin film solar cell, characterized in that the step of forming the antimony-selenide is performed for 5 to 20 minutes. The method of claim 1,
The forming of the antimony-selenide light absorption layer is a method of manufacturing an antimony-selenide thin film solar cell, characterized in that it is performed at a pressure ^{of 10 -1} Torr to 10 ^{-3 Torr.} The method of claim 1,
After forming the antimony selenide light absorption layer,
forming a buffer layer on the antimony selenide light absorption layer;
forming a transparent electrode on the buffer layer; and
forming a front electrode on the transparent electrode;
A method of manufacturing an antimony-selenide thin film solar cell comprising a. An antimony-selenide thin film solar cell manufactured by the method of claim 1 .

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