A kind of tandem solar cell and its preparation method

Abstract

The invention discloses a tandem solar cell which comprises at least two sub-cells. Each sub-cell comprises first-kind semiconductors and a second-kind semiconductor, wherein each first-kind semiconductor is formed by vertically stacking same-kind semi-conductor layers, and the energy gaps degrease gradually from top to bottom; the first-kind semiconductors are located on the lateral side of the second-kind semiconductor to form the sub-cell of a parallel connection structure. Metal electrodes are located on the lateral sides of the sub-cells. The tandem solar cell has the advantages that the tandem solar cell is simple in structure and few in material variety; the sub-cells are of the parallel connection structure, current matching needs not to be considered, low material requirements are achieved, and a process window is widened.

Description

technical field [0001] The invention relates to a preparation method of laminated solar cells, belonging to the technical field of solar cells. Background technique [0002] Conventional fossil fuels are being exhausted day by day. Among the existing sustainable energy sources, solar energy is undoubtedly the cleanest, most common and most potential alternative energy source. Solar power generation devices, also known as solar cells or photovoltaic cells, can directly convert solar energy into electrical energy. The principle of power generation is: sunlight shines on the semiconductor P-N junction to form hole-electron pairs. Under the action of the P-N junction electric field, the N-type The holes in the semiconductor move to the P-type region, and the electrons in the P-type region move to the N-type region. After the circuit is turned on, a current is formed. [0003] At present, the development of solar cells has gone through three stages. The technology development o...

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Problems solved by technology

[0006] However, the tandem solar cell with the above structure still has the following problems: (1) the structure of the existing tandem solar cell is relatively complicated. Taking the triple-junction tandem cell as an example, there are 8 semiconductor layers in total; (2) the triple-junction Take stacked batteries as an example, 8 layers of semiconductor layers with different bandgap widths require close lattice parameters and a high degree of matching, that is, the currents that each sub-cell in series can generate should be as consistent as possible; otherwise, the lattice mismatch is too high Large, it may cause carrier recombination, which seriously affects the conversion efficiency of solar cells, so the requirements for materials are high; (3) Since all cells are grown / deposited layer by layer, once defects appear in some layers, it will Successively affect the subsequent growth / deposition of the semiconductor layer, resulting in low efficiency or even failure of the entire battery, so its process requirements are relatively high

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