KR20200027402A - Solar cell and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a photovoltaic cell with improved efficiency and a manufacturing method thereof. More specifically, the photovoltaic cell comprises: a substrate; a first electrode, a second electrode, and at least one semiconductor film on the substrate, wherein the semiconductor film is interposed between the first and second electrodes; and a first connection film interposed between the first electrode and the semiconductor film and electrically connecting the first electrode and semiconductor film. The first connection film includes a plurality of two-dimensional films vertically extended from the top surface of the first electrode to the bottom surface of the semiconductor film. The two-dimensional films contain metal compounds.

Description

Solar cell and method for manufacturing the same

The present invention relates to a solar cell and its manufacturing method, and more particularly to a thin film solar cell and its manufacturing method.

In the two-dimensional material, adjacent layers are bonded by van der Waals forces, and thus the layer layer is peeled off. It is known that each layer of the two-dimensional material has a fast charge mobility because the carriers do not scatter because the adjacent layers are combined only with van der Waals attraction. This is a characteristic that is distinguished from general thin film-type compounds that maintain covalent or metal bonds between layers. Therefore, research and development on transistors using a two-dimensional material having fast charge mobility has been conducted.

Photovoltaic power generation that converts light energy into electrical energy using a photoelectric conversion effect has been widely used as a means of obtaining pollution-free energy. And with the improvement of the photoelectric conversion efficiency of the solar cell, a photovoltaic power generation system using a plurality of solar cell modules is also installed in a private house. The solar cell includes a semiconductor film having a p-n or p-i-n junction, and generates current using light incident on the semiconductor film.

The problem to be solved by the present invention is to provide a solar cell with improved efficiency.

Another problem to be solved by the present invention is to provide a method of manufacturing a solar cell with improved efficiency.

According to the concept of the present invention, a solar cell includes a substrate; A semiconductor film interposed between the first electrode, the second electrode, and the first and second electrodes on the substrate; And a first connection film interposed between the first electrode and the semiconductor film, and electrically connecting them to each other. The first connection film may include a plurality of two-dimensional films extending vertically from an upper surface of the first electrode to a bottom surface of the semiconductor film, and the two-dimensional films may include a metal compound. The connecting film is not included in the semiconductor film in which the photoelectric conversion phenomenon occurs.

According to another concept of the present invention, a method of manufacturing a solar cell includes forming a first electrode on a substrate; Performing a chalcogenation reaction on the first electrode to form a connecting film; And sequentially forming a semiconductor film and a second electrode on the connection film. Forming the connection layer may include forming a plurality of vertically oriented two-dimensional films by reacting a metal and a chalcogen precursor on the first electrode.

The solar cell according to the present invention can have a relatively large shunt (parallel) resistance using vertically oriented two-dimensional films. Thus, leakage current can be prevented. Furthermore, the solar cell according to the present invention can provide excellent efficiency in low light conditions.

1 is a perspective view showing a solar cell according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view of one cell of FIG. 1.
3 is a cross-sectional view taken along line A-A 'in FIG. 2.
4 and 5 illustrate a method of manufacturing a solar cell according to an embodiment of the present invention, and are cross-sectional views taken along line A-A 'in FIG. 2.
6 and 7 illustrate a method of manufacturing a solar cell according to another embodiment of the present invention, and are cross-sectional views taken along line A-A 'in FIG. 2.
8 illustrates a solar cell according to another embodiment of the present invention, and is a cross-sectional view taken along line A-A 'in FIG. 2.
9 and 10 is a perspective view showing a solar cell according to another embodiment of the present invention.

DETAILED DESCRIPTION In order to fully understand the constitution and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be implemented in various forms and various changes can be made. However, through the description of the present embodiments, the present disclosure is made to be complete, and the present invention is provided to those of ordinary skill in the art to fully inform the scope of the invention.

In the present specification, when a component is referred to as being on another component, it means that it may be formed directly on another component, or a third component may be interposed between them. In addition, in the drawings, the thickness of the components is exaggerated for effective description of the technical content. Parts indicated by the same reference numerals throughout the specification indicate the same components.

Although terms such as first, second, third, etc. are used to describe various components in various embodiments of the present specification, these components should not be limited by these terms. These terms are only used to distinguish one component from another component. The embodiments described and illustrated herein also include its complementary embodiments.

The terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, the singular form also includes the plural form unless otherwise specified in the phrase. As used herein, 'comprises' and / or 'comprising' does not exclude the presence or addition of one or more other components.

1 is a perspective view showing a solar cell according to an embodiment of the present invention. FIG. 2 is an enlarged perspective view of one cell of FIG. 1. 3 is a cross-sectional view taken along line A-A 'in FIG. 2.

1 to 3, a plurality of cells CE may be provided on the substrate SU. The plurality of cells CE may be connected to each other to configure a solar cell according to the present invention. The cells CE may have a line shape extending in the second direction D2. The cells CE may be arranged in the first direction D1. The plurality of cells CE may be connected to each other in series or parallel. For example, the substrate SU may include a silicon oxide film, stainless steel, plastic, or glass.

Each of the cells CE may include a first electrode EL1 sequentially stacked, a connection film CL, one or more semiconductor films SL, and a second electrode EL2. The connecting film CL is interposed between the first electrode EL1 and the semiconductor film SL, and can electrically connect them.

The semiconductor film SL may include a first semiconductor film SL1, a second semiconductor film SL2 and a third semiconductor film SL3. The second semiconductor film SL2 may be interposed between the first and third semiconductor films SL1 and SL3. The first semiconductor film SL1 may contact the connection film CL. In other words, the bottom surface of the first semiconductor film SL1 may contact the top surface of the connection film CL.

The first semiconductor film SL1 may have a first conductivity type, and the third semiconductor film SL3 may have a second conductivity type (eg, P type) different from the first conductivity type. For example, the first conductivity type may be N-type, and the second conductivity type may be P-type. As another example, the first conductivity type may be P type, and the second conductivity type may be N type. The second semiconductor film SL2 may be an intrinsic semiconductor. The second semiconductor film SL2 may function as a light absorbing layer. The thickness of the second semiconductor film SL2 may be greater than the thickness of the first semiconductor film SL1. The thickness of the second semiconductor film SL2 may be greater than the thickness of the third semiconductor film SL3. The thickness of the second semiconductor film SL2 may be 100 nm to 3,000 nm. More specifically, the thickness of the second semiconductor film SL2 may be 100 nm to 400 nm. As an example, the first to third semiconductor films SL1, SL2, and SL3 may include silicon, germanium, silicon-germanium, silicon oxide, or silicon carbide. The first to third semiconductor films SL1, SL2, and SL3 may be amorphous or fine crystalline.

The second electrode EL2 may be provided on the top surface of the third semiconductor film SL3. For example, the second electrode EL2 includes indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium oxide (IGO), indium zinc gallium oxide (IGZO), titanium zinc oxide (IZO), and combinations thereof It may include at least any one of. As another example, the second electrode EL2 may include W, Mo, Ti, Ag, Cu, Al, Ni, or alloys thereof.

Referring to FIGS. 2 and 3 again, the first electrode EL1 and the connection layer CL will be described in more detail. The connecting film CL may include a plurality of two-dimensional films NS. The direction of the crystal surface of the two-dimensional films NS may be oriented in a direction perpendicular to the upper surface of the substrate SU (ie, the third direction D3). The two-dimensional films NS may extend in the third direction D3 from the top surface of the first electrode EL1 to the bottom surface of the first semiconductor film SL1. In plan view, the two-dimensional films NS may be arranged randomly. That is, the two-dimensional films NS have a vertical orientation with respect to the substrate SU, but the first two-dimensional film may extend in the first direction D1 and the second two-dimensional film may extend in the second direction D2. The first direction D1 and the second direction D2 may intersect each other.

Each of the two-dimensional films NS may include metal chalcogenide. Each of the two-dimensional films NS may include a transition metal chalcogenide. In other words, each of the two-dimensional films NS may include a metal compound represented by a chemical formula of MX _y (eg, y is an integer of 1, 2 or 3). In the above formula, M is a metal or transition metal atom, and may include, for example, W, Mo, Ti, V, Zn, Hf or Zr. X is a chalcogen atom, and may include, for example, S, Se, O or Te. Each of the two-dimensional films (NS) is MoS ₂ , MoSe ₂ , MoTe ₂ , WS ₂ , WSe ₂ , WTe ₂ , ReS ₂ , ReSe ₂ , TiS ₂ , TiSe ₂ , TiTe ₂ , VO ₂ , VS ₂ , VSe ₂ , ZnO, ZnS ₂ , ZnSe ₂ , HfS ₂ , HfSe ₂ , WO ₃ , and may include any one selected from the group consisting of MoO ₃ .

The two-dimensional films NS may have semiconductor characteristics. The two-dimensional films NS may include a metal compound having the same first conductivity type as the first semiconductor film SL1. For example, when the first semiconductor film SL1 has an N type, the two-dimensional films NS are N-type MoS ₂ , MoSe ₂ , WS ₂ , ZnS ₂ , ZnSe ₂ , HfS ₂ , HfSe ₂ , ReSe ₂ , Or ReS ₂ . As another example, when the first semiconductor film SL1 has a P type, the two-dimensional films NS may include P-type WSe ₂ , graphene oxide, or VO ₂ . As another example, the two-dimensional films NS may have conductor characteristics. That is, the band gap energy of the two-dimensional films NS, which are conductors, may be substantially 0 eV. The two-dimensional material having a band gap energy of 0 eV may include TiS ₂ , TiSe ₂ , VS ₂ , or VSe ₂ .

Each of the two-dimensional films NS may have a monolayer structure having strong bonding force between constituent atoms. Alternatively, each of the two-dimensional films NS may have a structure in which the single layers overlap several layers. Here, adjacent single layers can be coupled to each other with very weak van der Waals attraction. In other words, the two-dimensional film NS may collectively refer to a film having the two-dimensional structure described above. For example, the two-dimensional film NS may have a single layer structure of metal chalcogenide or transition metal chalcogenide. Here, a single layer (monolayer) refers to one layer having the formula of MX ₂ when taking the metal decalcogenide as an example.

Referring again to FIG. 3, two-dimensional films NS adjacent to each other may be coupled to each other by van der Waals forces. For example, the first two-dimensional film NS and the second two-dimensional film NS adjacent thereto in the first direction D1 may be coupled to each other by van der Waals forces parallel to the first direction D1. . The two-dimensional films NS may have different heights. For example, one of the two-dimensional films NS may have a first height H1, and the other of the two-dimensional films NS may have a second height H2. In this case, the first height H1 and the second height H2 may be different.

The two-dimensional films NS may include the same material. In other words, the two-dimensional films NS may have the same composition. The two-dimensional films NS may have a single crystal structure or a polycrystalline structure. Each of the two-dimensional films NS may have a crystal structure oriented in the third direction D3. The two-dimensional films NS may have the same crystal structure or different crystal structures. For example, the crystal structure may include a hexagonal lattice structure, a cubic structure, a triangular column lattice structure, a tetragonal lattice structure, and a modified octagonal lattice structure (single tetragonal system).

In one embodiment, the first electrode EL1 may include the same metal as the metal of the two-dimensional films NS. When the two-dimensional films NS include a metal compound of MX _y , the first electrode EL1 may include a metal of M. For example, when the two-dimensional films NS include MoS ₂ , the first electrode EL1 may include Mo. This is because when forming the connection layer CL, the first electrode EL1 serves as a seed layer of the connection layer CL. In the manufacturing method, the relative thickness of the metal and the metal compound can be controlled by controlling the temperature and time.

In another embodiment, the first electrode EL1 may include a metal different from the metal constituting the two-dimensional films NS. The first electrode EL1 may be a transparent conductor. Specifically, the first electrode EL1 may include a transparent conducting layer. Transparent conductive films include indium tin oxide (ITO), tin oxide (SnO), F-doped tin oxide (FTO), zinc oxide (ZnO), titanium dioxide (TiO ₂ ), Ga-doped zinc oxide (GZO), or AZO ( Al-doped zinc oxide). When the first electrode EL1 is a transparent electrode including a transparent conductive film, the second electrode EL2 may also be formed of a transparent electrode including a transparent conductive film.

The first electrode EL1 may have a first thickness T1, and the connection layer CL may have a second thickness T2. The first thickness T1 may be 5 nm to 900 nm. In more detail, the first thickness T1 may be 5 nm to 100 nm. The second thickness T2 may be 15 nm to 100 nm. In more detail, the second thickness T2 may be 15 nm to 30 nm. For example, the first thickness T1 may be smaller than the second thickness T2. As another example, the first thickness T1 may be greater than the second thickness T2.

The solar cell according to embodiments of the present invention may include a connection film CL made of vertically oriented two-dimensional films NS. A current may flow between the first electrode EL1 and the semiconductor film SL through the two-dimensional films NS of the connection film CL. Since the two-dimensional films NS extend from the upper surface of the first electrode EL1 to the bottom surface of the semiconductor film SL in the third direction D3, the current flows through the two-dimensional films NS in the third direction D3. It can flow smoothly.

Solar cells are generally required to be used in low-light environments (ie, environments with low light intensity). In general, in low light conditions, the efficiency of solar cells is greatly reduced. The reason for the decrease in efficiency in low light is that in a low light condition in which the amount of photocharge generated is small, the effect of the leakage current is large, so that the efficiency of the solar cell can be greatly reduced. Leakage current is associated with shunt resistance. If the shunt resistance is large, the leakage current is small, whereas, if the shunt resistance is small, the leakage current is large.

The two-dimensional films NS may be horizontally separated from each other. For example, the two-dimensional films NS may be spaced apart from each other in the first direction D1 (see FIG. 3). Separation is a state that can be easily separated because it is combined only with a simple physical attraction. In this way, the flow of charge is inhibited between the layers that are bonded by the van der Waals bonding force. Therefore, the current flowing through the connection film CL is difficult to flow in a direction parallel to the upper surface of the substrate SU (for example, the first direction D1 or the second direction D2). In other words, the connection layer CL may have a relatively large shunt resistance. As a result, the solar cell according to the present invention can prevent leakage current from being generated. The solar cell according to the present invention can provide excellent efficiency in low light conditions.

4 and 5 illustrate a method of manufacturing a solar cell according to an embodiment of the present invention, and are cross-sectional views taken along line A-A 'in FIG. 2.

Referring to FIG. 4, the first electrode EL1 may be formed on the substrate SU. The first electrode EL1 may be formed with a third thickness T3. The first electrode EL1 may include metal M. For example, M may include W, Mo, Ti, V, Zn, Hf or Zr.

Referring to FIG. 5, a connection layer CL may be formed on the first electrode EL1. The connecting layer CL may be formed using a chalcogenization reaction of a part of the first electrode EL1. Alternatively, the connection layer CL may be formed by chalcogenizing a metal layer formed on the first electrode EL1.

The chalcogenization reaction may include providing a precursor of chalcogen X on the top surface of the first electrode EL1 or on the metal surface deposited on the first electrode EL1. For example, X may include S, Se, O or Te. The chalcogenation reaction may be performed under a temperature of 300 ° C to 1000 ° C. In more detail, the chalcogenation reaction may be performed under a temperature of 300 ° C to 530 ° C.

The metal M of the first electrode EL1 and the chalcogen X of the precursor react to form a plurality of two-dimensional films NS. The two-dimensional films NS may be grown in a vertical direction (ie, the third direction D3) from the upper surface of the first electrode EL1.

When the third thickness T3 of the first electrode EL1 is sufficiently thick, the two-dimensional films NS may be grown in the third direction D3. For example, the third thickness T3 may be 5 nm to 1,000 nm.

While the two-dimensional films NS are formed, the thickness of the first electrode EL1 is reduced, and the first electrode EL1 may have a first thickness T1. The first thickness T1 may be smaller than the third thickness T3. The connection layer CL may be formed with a second thickness T2. As the process temperature and the reaction time of the chalcogenation reaction increase, the second thickness T2 of the connection film CL may increase. In other words, as the process temperature and reaction time of the chalcogenation reaction increase, the height of the two-dimensional films NS (ie, H1 and H2 in FIG. 3) may increase. By controlling the process temperature and reaction time of the chalcogenation reaction, the thickness T2 of the connecting film CL can be controlled.

Referring back to FIGS. 1 to 3, a semiconductor film SL may be formed on the connection film CL. The formation of the semiconductor film SL may include sequentially forming the first semiconductor film SL1, the second semiconductor film SL2, and the third semiconductor film SL3 on the connection film CL. . The second electrode EL2 may be formed on the semiconductor film SL. A plurality of cells CE may be formed by patterning a stacked structure including the first electrode EL1, the connection layer CL, the semiconductor layer SL, and the second electrode EL2.

6 and 7 illustrate a method of manufacturing a solar cell according to another embodiment of the present invention, and are cross-sectional views taken along line A-A 'in FIG. 2. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to FIGS. 4 and 5 will be omitted, and differences will be described in detail.

Referring to FIG. 6, the first electrode EL1 may be formed on the substrate SU. The first electrode EL1 may be formed with a first thickness T1. The first electrode EL1 may include a transparent conductive film.

A metal layer ML may be formed on the first electrode EL1. The metal layer ML may include metal M. For example, M may include W, Mo, Ti, V, Zn, Hf or Zr. The metal layer ML may have a fourth thickness T4. The fourth thickness T4 may be 5 nm to 100 nm. In more detail, the fourth thickness T4 may be 5 nm to 10 nm.

Referring to FIG. 7, a connection layer CL may be formed from the metal layer ML. In other words, the metal layer ML may be converted into the connection layer CL. Since the connection layer CL is formed from the metal layer ML, the connection layer CL may be positioned on the first electrode EL1. The connection layer CL may be formed using a chalcogenization reaction using the metal layer ML as a precursor layer. The chalcogenation reaction may be performed until the metal layer (ML) partially or completely reacts. The chalcogenization reaction can be performed by providing a chalcogen precursor comprising S, Se, O or Te on the metal layer (ML).

Referring back to FIGS. 1 to 3, a semiconductor film SL may be formed on the connection film CL. The second electrode EL2 may be formed on the semiconductor film SL. As an example, the second electrode EL2 may also include a transparent conductive film. A plurality of cells CE may be formed by patterning a stacked structure including the first electrode EL1, the connection layer CL, the semiconductor layer SL, and the second electrode EL2.

When the first electrode EL1 and the second electrode EL2 are formed of a transparent electrode including a transparent conductive oxide, a transparent solar cell including a connecting film that transmits a portion of sunlight can be formed.

8 illustrates a solar cell according to another embodiment of the present invention, and is a cross-sectional view taken along line A-A 'in FIG. 2. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to FIGS. 1 to 3 are omitted, and differences are described in detail.

1, 2 and 8, the connection layer CL may include a first region RG1 and a second region RG2. The first region RG1 may include vertically oriented two-dimensional films NS, and the second region RG2 may include horizontally oriented two-dimensional films NS. For example, the two-dimensional films NS of the first region RG1 may extend in the third direction D3 from the top surface of the first electrode EL1. The two-dimensional films NS of the second region RG2 may extend in a first direction D1 which is a direction parallel to the top surface of the first electrode EL1. The two-dimensional films NS of the second region RG2 may be stacked in the third direction D3.

In the second region RG2, since the two-dimensional films NS are horizontally oriented, current in the second region RG2 may flow in a direction parallel to the upper surface of the substrate SU. For example, the second region RG2 may be surrounded by the first region RG1. The first region RG1 surrounding the second region RG2 may prevent current from flowing horizontally. As a result, the solar cell according to this embodiment can prevent leakage current from being generated.

9 is a perspective view showing a solar cell according to another embodiment of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to FIGS. 1 to 3 are omitted, and differences are described in detail.

Referring to FIG. 9, each of the cells CE is sequentially stacked with a first electrode EL1, a first connecting film CL1, a semiconductor film SL, a second connecting film CL2, and a second electrode ( EL2). The first connection layer CL1 is interposed between the first electrode EL1 and the first semiconductor layer SL1 to electrically connect them. The second connection layer CL2 is interposed between the second electrode EL2 and the third semiconductor layer SL3 to electrically connect them.

The first connection layer CL1 may include a metal compound having the same first conductivity type as the first semiconductor layer SL1. The second connection layer CL2 may include a metal compound having the same second conductivity type as the third semiconductor layer SL3. The first connection layer CL1 may include a metal compound that is a conductor.

Each of the first and second connecting films CL1 and CL2 may include a plurality of two-dimensional films oriented vertically. A detailed description of the two-dimensional films of the first and second connecting films CL1 and CL2 may be the same as described with reference to FIGS. 2 and 3 above. For example, the two-dimensional films of the second connection layer CL2 may extend from the top surface of the third semiconductor film SL3 to the bottom surface of the second electrode EL2 in the third direction D3.

The second electrode EL2 may include the same metal as the metal of the second connection layer CL2. When the second connection layer CL2 includes the metal compound of MX _y , the second electrode EL2 may include the metal of M. For example, when the second connection layer CL2 includes WSe ₂ two-dimensional layers, the second electrode EL2 may include W.

10 is a perspective view showing a solar cell according to still other embodiments of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to FIGS. 1 to 3 are omitted, and differences are described in detail.

Referring to FIG. 10, each cell CE is sequentially stacked with a first electrode EL1, a connecting film CL, a first semiconductor film SL1, a second semiconductor film SL2, and a second electrode. (EL2).

The first semiconductor film SL1 may be a light absorbing layer. The first semiconductor film SL1 may include a compound semiconductor. As an example, the first semiconductor film SL1 may include CuInGaSe (CIGS), CuInSe (CIS), or CdTe. The second semiconductor film SL2 may be a semiconductor film having a different conductivity type from the first semiconductor film SL1. The second semiconductor film SL2 may include a compound semiconductor, for example, any one or more of CdS, ZnO, and ZnS.

As described with reference to FIGS. 1 to 3, the connection film CL may include vertically oriented two-dimensional films NS. The two-dimensional films NS may extend in the third direction D3 from the top surface of the first electrode EL1 to the bottom surface of the first semiconductor film SL1. The first electrode EL1 and the first semiconductor film SL1 may be electrically connected through the two-dimensional films NS. The two-dimensional films NS of the connection film CL may prevent leakage of current between the first electrode EL1 and the first semiconductor film SL1.

Example  One

On the SiO ₂ / Si substrate, a Mo film was deposited to a thickness of 100 nm. Sulfurization reaction was performed on the Mo film to form a MoS ₂ film. The process temperature of the sulfiding reaction was maintained at about 350-500 ° C. When the reaction temperature was 500 ° C, the MoS ₂ film was formed to a thickness of 15 nm. As a result of performing TEM analysis on the formed MoS ₂ film, it was confirmed that the MoS ₂ two-dimensional films were vertically oriented. A 10 nm N-type Si film, a 300 nm intrinsic Si film, and a 10 nm P-type Si film were sequentially formed on the MoS ₂ film. An ITO transparent electrode was formed on the P-type Si film.

Example  2

A solar cell was manufactured in the same manner as in Example 1, except that the process temperature of the sulfidation reaction was maintained at about 700 ° C. At this time, the MoS ₂ film was formed to a thickness of 90 nm.

Example  3

On the SiO ₂ / Si substrate, a Mo film was deposited to a thickness of 100 nm. A selenization reaction was performed on the Mo film to form a MoSe ₂ film. The process temperature of the selenization reaction was maintained at about 350-500 ° C. When the reaction temperature was 500 ° C, the MoSe ₂ film was formed to a thickness of 15 nm. Thereafter, a solar cell was manufactured in the same manner as in Example 1.

Comparative example  One

A solar cell was manufactured in the same manner as in Example 1, except that the MoS ₂ film was not formed on the Mo film. In other words, in the solar cell according to Comparative Example 1, the MoS ₂ film of Example 1 was omitted.

Experimental example  One

The solar cell of Example 1 and the solar cell of Comparative Example 1 were measured for open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), efficiency, shunt resistance, and series resistance, respectively. It is shown in Table 1 below. The light intensity was adjusted to 100 mW / cm ² .

VOC
(V) JSC
(mA / cm ² ) FF
(%) efficiency
(%) Shunt resistance
(Ω) Series resistance
(Ω) Example 1 0.831 11.0 54.2 4.95 4600 81 Comparative Example 1 0.789 10.42 40.1 3.30 1500 190

Referring to Table 1, the solar cell according to Example 1, VOC, JSC, FF and efficiency were all increased compared to the solar cell of Comparative Example 1. The solar cell according to Example 1 increased the shunt resistance by about 3 times, and the series resistance decreased to about 2/5 compared to the solar cell of Comparative Example 1. This significantly increased FF and efficiency.

Experimental example  2

The intensity of light irradiated to the solar cell of Example 1 was changed, and the results are shown in Table 2 below.

Light intensity VOC
(V) JSC
(mA / cm ² ) FF
(%) efficiency
(%) Shunt resistance
(Ω) 100 mW / cm ² 0.831 11.0 54.2 4.95 4600 90 mW / cm ² 0.829 9.98 54.9 5.05 4900 80 mW / cm ² 0.828 8.86 55.6 5.10 5900 70 mW / cm ² 0.827 7.87 56.3 5.24 6700 60 mW / cm ² 0.824 6.77 57.0 5.30 8200 50 mW / cm ² 0.822 5.65 58.0 5.39 9000 40 mW / cm ² 0.818 4.50 58.8 5.41 12000 30 mW / cm ² 0.812 3.37 59.7 5.45 14000 20 mW / cm ² 0.804 2.33 60.3 5.65 18000

Referring to Table 2, it can be seen that as the light intensity decreased, the shunt resistance increased. Particularly, when the light intensity is 20 mW / cm ² , the shunt resistance is 18000 Ω and the efficiency is 5.65%, which confirms that the electrical characteristics of the solar cell are excellent. As a result, it can be seen that the solar cell according to the embodiment of the present invention exhibits excellent performance in low light conditions.

Experimental example  3

For the solar cell of Example 3 and the solar cell of Comparative Example 1, open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), efficiency, shunt resistance, and series resistance were measured, respectively, and the results were measured. It is shown in Table 3 below. The light intensity was adjusted to 100 mW / cm ² .

VOC
(V) JSC
(mA / cm ² ) FF
(%) efficiency
(%) Shunt resistance
(Ω) Series resistance
(Ω) Example 3 0.777 11.61 62.7 5.65 5500 46 Comparative Example 1 0.718 9.90 42.5 3.02 2900 170

Referring to Table 3, it can be seen that the solar cell according to Example 3 increases the shunt resistance and decreases the series resistance compared to the solar cell of Comparative Example 1.

As another embodiment of the present invention, by depositing a Mo metal on a transparent first electrode on a transparent substrate to form a MoSe ₂ layer of 20 nm with a reaction temperature of 500 ° C to prepare a transparent solar cell showing 26% transmittance When the light irradiation condition of 7 MW / cm ² , shunt resistance of 32000 Ω and greatly improved efficiency of 7.7% can be obtained.

The metal compound that is the two-dimensional material presented several times may be M _a X _b (a, b = a positive integer excluding 0) (M: metal; X: chalcogen element).

The embodiments of the present invention have been described above with reference to the accompanying drawings, but those of ordinary skill in the art to which the present invention pertains can implement the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (17)

Board;
A first electrode, a second electrode, and at least one semiconductor film interposed between the first and second electrodes on the substrate; And
Interposed between the first electrode and the semiconductor film, including a first connection film for electrically connecting them to each other,
The first connection film includes a plurality of two-dimensional films extending vertically from an upper surface of the first electrode to a bottom surface of the semiconductor film,
The two-dimensional film is a solar cell comprising a metal compound.
According to claim 1,
Each of the two-dimensional films has a structure in which a plurality of two-dimensional monolayers are overlapped, and a solar cell having van der Waals attraction between adjacent single layers.
According to claim 1,
The first electrode, a solar cell comprising the same metal as the metal of the two-dimensional films.
According to claim 1,
The first electrode includes a metal M,
The metal compound of the two-dimensional films has the formula MX _y ,
The M includes W, Mo, Ti, V, Zn, Hf or Zr,
The X includes S, Se, O or Te,
The y is 1, 2 or 3 solar cell.
According to claim 1,
The two-dimensional films are oriented perpendicular to the substrate,
The first two-dimensional film of the two-dimensional film is extended in the first direction,
The second two-dimensional film of the two-dimensional film is extended in the second direction,
The solar cell in which the first direction and the second direction intersect each other.
According to claim 1,
The first connecting layer includes a first region and a second region,
The two-dimensional films of the first region are oriented vertically,
The two-dimensional films of the second region are horizontally oriented solar cells.
According to claim 1,
The semiconductor film includes a first semiconductor film and a second semiconductor film on the first semiconductor film,
The first semiconductor film has a first conductivity type,
The second semiconductor film has a second conductivity type different from the first conductivity type,
The first connection film is interposed between the first electrode and the first semiconductor film,
The two-dimensional films are solar cells having the first conductivity type.
The method of claim 7,
Each of the first and second semiconductor films includes a silicon, germanium, silicon-germanium or silicon carbide, silicon oxide film.
The method of claim 7,
The first semiconductor film includes CuInGaSe (CIGS), CuInSe (CIS), or CdTe,
The second semiconductor film comprises a CdS, ZnS, or ZnO solar cell.
According to claim 1,
Further comprising a second connecting film interposed between the semiconductor film and the second electrode,
The second connection film, a solar cell including a plurality of two-dimensional films extending vertically from the top surface of the semiconductor film to the bottom surface of the second electrode.
According to claim 1,
At least one of the first and second electrodes comprises a transparent conductive film.
The method of claim 11,
The transparent conductive film is a solar cell comprising ZnO, InSnO or SnO.
Forming a first electrode on the substrate;
Performing a chalcogenation reaction on the first electrode to form a connecting film; And
On the connecting film, comprising sequentially forming a semiconductor film and a second electrode,
The method of manufacturing the solar cell includes forming a plurality of two-dimensional films vertically oriented by reacting a metal and a chalcogen precursor on the first electrode.
The method of claim 13,
A method of manufacturing a solar cell, wherein at least one region of the two-dimensional films is grown vertically from an upper surface of the first electrode.
The method of claim 13,
Each of the two-dimensional films, a method of manufacturing a solar cell having a structure in which single layers are bonded to each other by van der Waals attraction.
The method of claim 13,
Forming the semiconductor film includes forming a first semiconductor film on the connection film and a second semiconductor film on the first semiconductor film,
The first semiconductor film has a first conductivity type,
The second semiconductor film has a second conductivity type different from the first conductivity type,
The two-dimensional film is a method of manufacturing a solar cell having the first conductivity type.
The method of claim 13,
A method of manufacturing a solar cell further comprising controlling the process temperature of the chalcogenation reaction to control the thickness of the connecting film.

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