SOLAR CELL AND METHOD OF FABRICATING SAME
A solar cell according to the present embodiment may have a tandem structure comprising a photovoltaic part, wherein the photovoltaic part comprises: a first photovoltaic part comprising: a photovoltaic layer composed of a perovskite compound; and a second photovoltaic part comprising a semiconductor substrate. Here, in the second photovoltaic part, a first semiconductor layer and a second semiconductor layer, which are formed separately from the semiconductor substrate on one side or the other side of the semiconductor substrate, may have different structures from each other.
1 . A solar cell, comprising:
a photovoltaic part including a first photovoltaic part that includes a photovoltaic layer composed of a perovskite compound and a second photovoltaic part that includes a semiconductor substrate;
a first electrode electrically connected to the photovoltaic part on one side of the photovoltaic part; and
a second electrode electrically connected to the photovoltaic part on the other side of the photovoltaic part,
wherein the second photovoltaic part includes the semiconductor substrate, a first semiconductor layer that is formed separately from the semiconductor substrate on one side of the semiconductor substrate, and a second semiconductor layer that is formed separately from the semiconductor substrate on the other side of the semiconductor substrate and has a crystal structure different from that of the first semiconductor layer.
2 . The solar cell of claim 1 , wherein the first semiconductor layer positioned on a front side of the semiconductor substrate includes an amorphous portion, and
the second semiconductor layer positioned on a rear side of the semiconductor substrate includes a polycrystalline portion.
3 . The solar cell of claim 1 , wherein in the second photovoltaic part, the first semiconductor layer positioned adjacent to the first photovoltaic part includes an amorphous portion, and
in the second photovoltaic part, the second semiconductor layer positioned on a surface opposite to the first photovoltaic part includes a polycrystalline portion.
4 . The solar cell of claim 3 , wherein a thickness of the second semiconductor layer is greater than that of the first semiconductor layer.
5 . The solar cell of claim 1 , wherein the first semiconductor layer includes an amorphous portion,
the second semiconductor layer includes a polycrystalline portion, and
a hydrogen content of the first semiconductor layer is greater than that of the second semiconductor layer.
6 . The solar cell of claim 1 , further comprising:
a first intermediate film positioned between the semiconductor substrate and the first semiconductor layer and a second intermediate film positioned between the semiconductor substrate and a second conductive region,
wherein materials or thicknesses of the first interlayer and the second interlayer are different from each other.
7 . The solar cell of claim 6 , wherein the semiconductor substrate and the first semiconductor layer have a hetero-junction structure having different crystal structures with the first intermediate layer composed of a semiconductor material therebetween, and
the semiconductor substrate and the second semiconductor layer have an insulating junction structure or a tunnel-junction structure in which the semiconductor substrate and the second semiconductor layer are bonded to each other with the second intermediate layer composed of an insulating material therebetween.
8 . The solar cell of claim 6 , wherein the first semiconductor layer includes an amorphous portion,
the second semiconductor layer includes a polycrystalline portion,
the first intermediate film includes a semiconductor material, and
the second intermediate film contains an insulating material.
9 . The solar cell of claim 8 , wherein the first intermediate film contains intrinsic amorphous silicon, and
the second intermediate film contains silicon oxide.
10 . The solar cell of claim 8 , wherein a thickness of the second intermediate film is smaller than that of the first intermediate film.
11 . The solar cell of claim 8 , wherein a hydrogen content of the first intermediate film is greater than a hydrogen content of the second intermediate film.
12 . The solar cell of claim 1 , wherein the first photovoltaic part is positioned on one side of the second photovoltaic part,
the first electrode is positioned on the first photovoltaic part,
the second electrode is positioned on the second semiconductor layer of the second photovoltaic part,
the second semiconductor layer includes a polycrystalline portion, and
a stacked structure of the first electrode and the second electrode are different from each other.
13 . The solar cell of claim 12 , wherein the first electrode includes a first electrode layer that is formed on the first photovoltaic part and contains a transparent conductive material, and a second electrode layer that is formed on the first electrode layer and contains a metal, and
the second electrode layer includes a metal electrode layer that is formed on the second electrode layer and contains a metal.
14 . The solar cell of claim 12 , further comprising:
at least one of an anti-reflection film formed on the first electrode layer and an optical film formed on the second semiconductor layer.
15 . A method of fabricating a solar cell, comprising:
forming a second photovoltaic part including a semiconductor substrate, a first semiconductor layer that is formed separately from the semiconductor substrate on one side of the semiconductor substrate, and a second semiconductor layer that is formed separately from the semiconductor substrate on the other side of the semiconductor substrate and has a crystal structure different from that of the first semiconductor layer;
forming a first photovoltaic part including a photovoltaic layer composed of a perovskite compound on the first semiconductor layer; and
forming a first electrode electrically connected to the first photovoltaic part on one side of the first photovoltaic part and a second electrode electrically connected to the second photovoltaic part on the other side of the second photovoltaic part.
16 . The method of claim 15 , wherein the forming of the second photovoltaic part includes:
forming a second portion including the second semiconductor layer including a polycrystalline portion on the other side of the semiconductor substrate; and
forming a first portion including the first semiconductor layer including an amorphous portion on the one side of the semiconductor substrate.
17 . The method of claim 16 , further comprising:
injecting hydrogen into the second semiconductor layer between the forming of the second portion and the forming of the first portion,
wherein in the forming of the first portion, a process of injecting the hydrogen into the first semiconductor layer is performed together.
18 . The method of claim 16 , wherein a temperature of a process of forming the first semiconductor layer is lower than that of a process of forming the second semiconductor layer, and
a pressure of the process of forming the first semiconductor layer is higher than that of the process of forming the second semiconductor layer.
19 . The method of claim 16 , wherein in the forming of the second portion, the second portion formed on the one side is removed to form the second portion on the other side after forming the second portion on both sides of the semiconductor substrate by a double-sided deposition process, and
in the forming of the first portion, the first portion is formed on the one side of the semiconductor substrate by a single-sided deposition process.
20 . The method of claim 16 , wherein the forming of the second portion further includes a process of forming a second intermediate film before a process of forming the second semiconductor layer,
the forming of the first portion further includes a process of forming a first intermediate film before a process of forming the first semiconductor layer,
the process of forming the second intermediate film and the process of forming the second semiconductor layer are formed by a continuous process, and
the process of forming the first intermediate film and the process of forming the first semiconductor layer are formed by the continuous process.