Tandem thin-film silicon solar cell and method for manufacturing the same
A tandem thin-film silicon solar cell comprises a transparent substrate, a first unit cell positioned on the transparent substrate, the first unit cell comprising a p-type window layer, an i-type absorber layer and an n-type layer, an intermediate reflection layer positioned on the first unit cell, the intermediate reflection layer including a hydrogenated n-type microcrystalline silicon oxide of which the oxygen concentration is profiled to be gradually increased and a second unit cell positioned on the intermediate reflection layer, the second unit cell comprising a p-type window layer, an i-type absorber layer and an n-type layer.
1. A tandem thin-film silicon solar cell, comprising:
a transparent substrate;
a first unit cell positioned on the transparent substrate, the first unit cell comprising a p-type window layer, an i-type absorber layer and an n-type layer;
an intermediate reflection layer positioned directly on the n-type layer of the first unit cell, the intermediate reflection layer including a hydrogenated n-type microcrystalline silicon oxide of which the oxygen concentration is profiled to be gradually increased from the first unit cell;
a second unit cell positioned on the intermediate reflection layer, the second unit cell comprising a p-type window layer, an i-type absorber layer and an n-type layer; and
wherein the n-type layer of the first unit cell includes hydrogenated n-type microcrystalline silicon.
2. The solar cell according to claim 1 , wherein the intermediate reflection layer has a thickness of 10 to 100 nm.
3. The solar cell according to claim 1 , wherein the intermediate reflection layer has a refractive index of around 2.0.
4. The solar cell according to claim 1 , wherein the intermediate reflection layer has a resistivity of 10 2 to 10 5 Ω·sm.
5. The solar cell according to claim 1 , wherein the first unit cell includes hydrogenated amorphous silicon.
6. The solar cell according to claim 1 , wherein the second unit cell includes hydrogenated amorphous silicon or hydrogenated microcrystalline silicon.
7. The solar cell according to claim 1 , comprising two or three unit cells.
8. The solar cell according to claim 1 , wherein a first position in the hydrogenated n-type microcrystalline silicon oxide is spaced from the transparent substrate by a first distance and a second position in the hydrogenated n-type microcrystalline silicon oxide is spaced from the transparent substrate by a second distance, the first distance being greater than the second distance, and wherein a first oxygen concentration at the first position is greater than a second oxygen concentration at the second position.