Solar cell
Disclosed is a solar cell including a semiconductor substrate, a conductive area including first and second conductive areas disposed on one surface of the semiconductor substrate, and an electrode including a first electrode connected to the first conductive area and a second electrode connected to the second conductive area. The electrode includes an adhesive layer disposed on the semiconductor substrate or the conductive area, an electrode layer disposed on the adhesive layer and including a metal as a main component, and a barrier layer disposed on the electrode layer and including a metal that is different from the metal of the electrode layer as a main component. The electrode layer has a thickness greater than a thickness of each of the adhesive layer and the barrier layer, and the barrier layer has a higher melting point than a melting point of the electrode layer.
1. A solar cell comprising:
a semiconductor substrate;
a conductive area including first and second conductive areas disposed on one surface of the semiconductor substrate; and
an electrode including a first electrode connected to the first conductive area and a second electrode connected to the second conductive area,
wherein the electrode includes an adhesive layer disposed on the semiconductor substrate or the conductive area, an electrode layer disposed on the adhesive layer and including a metal as a main component, and a barrier layer disposed on the electrode layer and including a metal that is different from the metal of the electrode layer as a main component,
wherein the electrode layer has a thickness greater than a thickness of each of the adhesive layer and the barrier layer,
wherein the barrier layer has a higher melting point than a melting point of the electrode layer,
wherein the entire adhesive layer is disposed between the conductive area and the electrode layer, and
wherein a width of the electrode layer is different from a width of the adhesive layer.
2. The solar cell according to claim 1 , wherein the barrier layer includes a refractory metal as a main component.
3. The solar cell according to claim 1 , wherein the barrier layer includes titanium (Ti), molybdenum (Mo), chromium (Cr), or tungsten (W) as a main component.
4. The solar cell according to claim 1 , wherein the barrier layer has a smaller coefficient of thermal expansion than a coefficient of thermal expansion of the electrode layer.
5. The solar cell according to claim 1 , wherein the barrier layer has a greater thickness than a thickness of the adhesive layer.
6. The solar cell according to claim 5 , wherein the adhesive layer and the barrier layer have a thickness ratio within a range from 1:2 to 1:30.
7. The solar cell according to claim 5 , wherein the barrier layer has a thickness of 80 nm or less.
8. The solar cell according to claim 1 , wherein the barrier layer has a specific resistance equal to or less than a specific resistance of the adhesive layer.
9. The solar cell according to claim 8 , wherein the specific resistance of the barrier layer is higher than a specific resistance of the electrode layer.
10. The solar cell according to claim 1 , wherein the barrier layer has a light-transmittance lower than a light-transmittance of the adhesive layer.
11. The solar cell according to claim 1 , wherein the adhesive layer includes a refractory metal as a main component.
12. The solar cell according to claim 1 , wherein the adhesive layer includes titanium (Ti), molybdenum (Mo), chromium (Cr) or tungsten (W) as a main component.
13. The solar cell according to claim 1 , wherein the adhesive layer has a coefficient of thermal expansion between a coefficient of thermal expansion of the semiconductor substrate or the conductive area and a coefficient of thermal expansion of a portion of the electrode layer that is adjacent to the adhesive layer.
14. The solar cell according to claim 1 , wherein the adhesive layer has a thickness of 50 nm or less.
15. The solar cell according to claim 1 , wherein the adhesive layer and the barrier layer, disposed on opposite surfaces of the electrode layer, are formed of the same material.
16. The solar cell according to claim 1 , wherein the electrode layer includes at least one of copper (Cu), aluminum (Al), silver (Ag), gold (Au) and alloys thereof as a main component.
17. The solar cell according to claim 1 , wherein the electrode further includes a pad layer disposed on the barrier layer and connected to a ribbon.
18. The solar cell according to claim 17 , wherein the pad layer includes at least one of tin and a nickel-vanadium alloy (NiV) as a main component.
19. The solar cell according to claim 1 , wherein the adhesive layer comes into contact with the semiconductor substrate or the conductive area,
wherein the electrode layer comes into contact with the adhesive layer, and
wherein the barrier layer comes into contact with the electrode layer.
20. The solar cell according to claim 1 , wherein the electrode layer is on an outer surface of the adhesive layer.