Tandem solar cell and manufacturing method therefor

1 . A method of manufacturing a tandem solar cell, the method comprising:

a step of preparing a perovskite solar cell, including a first conductive charge transporting layer, a light absorption layer, and a second conductive charge transporting layer, on a substrate;

a step of forming a partition part in the perovskite solar cell to form a first perovskite unit solar cell and a second perovskite unit solar cell;

a step of forming a contact part in the first perovskite unit solar cell to expose a top surface of the first conductive charge transporting layer of the first perovskite unit solar cell by removing a certain region of each of the light absorption layer and the second conductive charge transporting layer of the first perovskite unit solar cell;

a step of forming a buffer layer in a first portion of a top surface of each of the first perovskite unit solar cell and the second perovskite unit solar cell to expose a second portion of the top surface of each of the first perovskite unit solar cell and the second perovskite unit solar cell;

a step of preparing a plurality of second solar cells;

a step of bonding the plurality of second solar cells to the buffer layer to form a first unit tandem solar cell where the first perovskite unit solar cell, the buffer layer, and the second solar cell are sequentially stacked and a second unit tandem solar cell where the second perovskite unit solar cell, the buffer layer, and the second solar cell are sequentially stacked; and

a step of electrically connecting the first unit tandem solar cell to the second unit tandem solar cell using a connection line,

wherein the connection line extends from a top surface of the second solar cell of the second unit tandem solar cell to the top surface of the first conductive charge transporting layer exposed at the contact part of the first perovskite unit solar cell through side surfaces of the buffer layer and the second solar cell of the second unit tandem solar cell, the second portion of the top surface of the second perovskite unit solar cell, and a side surface of the second perovskite unit solar cell, and

wherein the buffer layer and the plurality of second solar cell do not overlap the contact part.

2 . The method of claim 1 , wherein the step of preparing the perovskite solar cell comprises a step of sequentially forming the first conductive charge transporting layer, the light absorption layer, and the second conductive charge transporting layer on the substrate.

3 . The method of claim 1 , wherein the step of forming the partition part comprises a process of removing a certain region of each of the first conductive charge transporting layer, the light absorption layer, and the second conductive charge transporting layer to expose a top surface of the substrate.

4 . The method of claim 1 , wherein the step of forming the buffer layer comprises a process of forming a film, including a plurality of holes, in the top surface of each of the first perovskite unit solar cell and the second perovskite unit solar cell and a process of filling a conductive layer into the plurality of holes included in the film.

5 . The method of claim 4 , wherein the process of forming the film including the plurality of holes comprises a process of forming the film in a semi-dried state, and the step of forming the first unit tandem solar cell and the second unit tandem solar cell comprises a process of placing the second solar cell on the buffer layer and then curing the film in the semi-dried state.

6 . The method of claim 4 , wherein the plurality of holes included in the film comprises a plurality of first holes passing through the film and extending in a first direction and a plurality of second holes passing through the film and extending in a second direction intersecting with the first direction, and

the conductive layer contacts a top surface of each of the first and second perovskite unit solar cells and a bottom surface of the second solar cell.

7 . The method of claim 4 , wherein the film does not overlap the contact part, and the contact part is not covered by the film and is exposed.

8 . The method of claim 1 , wherein the step of electrically connecting the first unit tandem solar cell to the second unit tandem solar cell electrically connects an electrode pattern, included in a top surface of the second solar cell of the second unit tandem solar cell, to the first conductive charge transporting layer of the first perovskite unit solar cell exposed at a contact part of the first unit tandem solar cell by using the connection line.

9 . The method of claim 8 , wherein the one connection line extends along a side surface of the second solar cell of the second unit tandem solar cell and a side surface of the buffer layer under the second solar cell, extends along a top surface and a side surface of the second conductive charge transporting layer and a side surface of a light absorption layer of the first perovskite unit solar cell provided at one side of the contact part across the partition part, and extends up to a top surface of the first conductive charge transporting layer of the first perovskite unit solar cell exposed at the contact part.

10 . The method of claim 4 , wherein the step of preparing the plurality of second solar cells comprises a process of forming an electrode pattern having a same pattern as a pattern of the conductive layer, and

the step of bonding the plurality of second solar cells comprises a process of allowing the conductive layer to overlap the electrode pattern.