Tandem solar cell and method of manufacturing the same
The present disclosure relates to a tandem solar cell and a method of manufacturing the same, and more particularly, to a tandem solar cell having a perovskite solar cell stacked on and bonded to a silicon solar cell and a method of manufacturing the same. According to the present disclosure, a tandem solar cell embodied by using a homojunction silicon solar cell is provided with a first passivation pattern so that a part of an emitter layer under the first passivation pattern is exposed, thereby protecting, by the first passivation pattern, the emitter layer during high temperature firing for forming a second electrode, reducing surface defects of the emitter layer, and reducing a problem in that characteristics of the perovskite solar cell are degraded.
1. A tandem solar cell comprising:
a first solar cell that includes (i) a crystalline silicon substrate, (ii) an emitter layer coupled to a first surface of the crystalline silicon substrate, and (iii) a first passivation pattern that includes hydrogen, that is coupled to the emitter layer, and that is patterned to have an opening through which a portion of the emitter layer is exposed;
a second solar cell that includes a perovskite absorption layer;
a transparent conductive oxide (TCO) inter-layer that is disposed on the first passivation pattern of the first solar cell, that is filled in the opening, and that directly contacts the emitter layer and the second solar cell;
a first electrode that is coupled to the second solar cell, the first electrode including no glass frit;
a rear electric field layer disposed on a second surface the crystalline silicon substrate;
a second passivation layer disposed on the rear electric field layer; and
a second electrode that directly contacts the rear electric field layer through the second passivation layer, the second electrode comprising a glass frit and an inorganic additive for a thermal process to connect the second electrode to the rear electric field layer through the second passivation layer,
wherein the second solar cell further includes:
an electron transfer layer that is coupled to the inter-layer,
a hole transfer layer that is coupled to the first electrode, and
a mesoporous layer that is coupled between the electron transfer layer and the perovskite absorption layer.
2. The tandem solar cell of claim 1 , wherein the first electrode includes:
a transparent electrode layer that is coupled to the second solar cell, and
a grid electrode layer that is coupled to the transparent electrode layer.
3. The tandem solar cell of claim 2 , wherein the transparent electrode layer includes a concave structure and a convex structure.
4. The tandem solar cell of claim 1 , wherein the first passivation pattern has a thickness of 10 to 100 nm.
5. The tandem solar cell of claim 1 , wherein at least one of the first surface of the crystalline silicon substrate or the second surface of the crystalline silicon substrate includes a texturing pattern.
6. The tandem solar cell of claim 1 , wherein the first solar cell includes a silicon solar cell and the second solar cell includes a perovskite solar cell.
7. The tandem solar cell of claim 1 , wherein an area of the portion of the emitter layer exposed through the opening is in a range of 0.1% to 30% of an entire surface of the first solar cell.
8. The tandem solar cell of claim 1 , wherein the rear electric field layer directly contacts the second surface of the crystalline silicon substrate.
9. The tandem solar cell of claim 8 , wherein the second passivation layer directly contacts the rear electric field layer.
10. The tandem solar cell of claim 1 , wherein the rear electric field layer covers the second surface of the crystalline silicon substrate and separates the second electrode from the second surface of the crystalline silicon substrate.
11. The tandem solar cell of claim 1 , wherein the second electrode has:
a first end that penetrates the second passivation layer, that physically connects to the rear electric field layer, and that is spaced apart from the second surface the crystalline silicon substrate; and
a second end that protrudes to an outside of the second passivation layer.
12. The tandem solar cell of claim 1 , wherein the second passivation layer partly covers the rear electric field layer, and the second electrode occupies 1 to 30% of a total area of a lower surface of the second passivation layer.
13. The tandem solar cell of claim 1 , wherein the electron transfer layer is in direct contact with the inter-layer, and the hole transfer layer is in direct contact with the first electrode.
14. The tandem solar cell of claim 1 , wherein the mesoporous layer is in direct contact with the electron transfer layer and the perovskite absorption layer.
15. The tandem solar cell of claim 1 , wherein the TCO inter-layer includes concave portions protruding toward the second solar cell and convex portions protruding toward the first solar cell relative to the concave portions.
16. The tandem solar cell of claim 15 , wherein the first passivation pattern covers at least one of the concave portions or the convex portions.
17. The tandem solar cell of claim 15 , wherein the emitter layer includes:
a first portion that is in direct contact with the concave portions or the convex portions of the TCO inter-layer; and
a second portion that is in direct contact with the first passivation pattern, and
wherein the first passivation pattern extends along the TCO inter-layer and is disposed between one of the concave portions and one of the convex portions.
18. The tandem solar cell of claim 17 , wherein the first passivation pattern further extends along the TCO inter-layer and cover the one of the concave portions and the one of the convex portions.