Three-junction solar cell with quantum well structure

Abstract

The invention discloses a three-junction solar cell with a quantum well structure. The three-junction solar cell sequentially comprises a first subsidiary cell as a substrate, a first tunnel junction, a second subsidiary cell, a second tunnel junction and a third subsidiary cell. Lattice matching is adopted among the three subsidiary cells, and the three subsidiary cells are connected through the tunnel junctions. The first subsidiary cell is a Ge cell, the second subsidiary cell is an InxGa1-xNyAs1-y / GaAs quantum well cell, and the third subsidiary cell is a GaInP cell. According to the solar cell, the formed energy band gap combination is about 0.67 eV / 1.3 eV / 1.8 eV, the energy band gap difference delta Eg1 of the second subsidiary cell and the first subsidiary cell is about 0.63, the energy band gap difference delta Eg2 of the third subsidiary cell and the second subsidiary cell is about 0.5 eV, and the two energy band gap differences are more approximate; moreover, the energy band gap of the third subsidiary cell GaInP is about 1.8 eV, more photons can be absorbed in comparison with a traditional GaInP cell, and therefore currents of the three subsidiary cells can be distributed more evenly.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaics, in particular to a triple-junction solar cell with a quantum well structure. Background technique [0002] In the field of photovoltaics, the most efficient cell is the high-efficiency multi-junction solar cell. According to the report of the French company Soitec in 2014, the efficiency of the high-efficiency four-junction cell developed by it can reach 44.7% under concentrated light, setting a new world record. In principle, a high-efficiency multi-junction solar cell refers to a photovoltaic cell composed of two or more sub-cells superimposed, and its mainstream is based on III-V compound semiconductor materials and prepared by crystal growth. The main principle of this type of battery is to use the bandwidth-matched sub-cells in the battery to absorb different bands of the solar spectrum, so as to realize the efficient utilization of the full-spectrum subdivision of the solar spec...

AI Technical Summary

Problems solved by technology

However, there are not many options for 1eV batteries. In addition to GaInAs with a high In composition, there are also GaInNAs materials (also known as dilute nitrogen materials) with an N composition of about 2% to 3%. GaInAs with a high In composition is due to In The composition is high, and the lattice fit with the other three sub-cells is very large, and it is difficult to grow even with a lattice gradient buffer layer; and in GaInNAs materials, because N will introduce some deep-level recombination centers and background doping , therefore, directly grown GaInNAs subcells tend to be inefficient

[0005] To sum up, in order to obtain high-efficiency three-junction or four-junction solar cells with high current matching, the various methods currently used may have lattice mismatch or low-quality battery materials. Affects the efficiency of solar cells

Images