Intermediate band solar cell structure based on rare bismuth phosphide

Abstract

The invention discloses an intermediate band solar cell structure based on a rare bismuth phosphide. A small amount of bismuth atoms are doped into a phosphide, a new impurity energy band is generated in a forbidden band of the phosphide, distance of the impurity energy band and a conduction band of the phosphide and distance of the impurity energy band and a valence band of the phosphide can be regulated and controlled by changing Al, Ga and In element components in the phosphide, and more than 60% of theoretically expected photoelectric conversion efficiency is realized in a relatively wide range. The impurity energy band caused by the bismuth atoms has very strong photoluminescence at room temperature, which proves that nonradiative recombination in a material is little, and which is beneficial to manufacture of a solar device. The novel intermediate band solar cell structure can adopts various methods of conventional molecular beam epitaxy, metallorganic chemical vapor deposition and the like to grow. Compared with a conventional technical scheme which adopts quantum dots as an intermediate band, strain in the cell structure provided by the invention is relatively small and easy to compensate or regulate and control, thickness of an absorption area is increased to achieve full absorption of sunlight of a corresponding wave band, and conversion efficiency is improved.

Description

technical field [0001] The invention relates to a solar cell based on an intermediate band, in particular to a novel high-efficiency solar cell structure using dilute bismuth phosphide as an intermediate band. It belongs to the field of semiconductor optoelectronic material preparation Background technique [0002] Today's world energy issue is an important issue facing all countries in the world. At present, human beings mainly rely on oil and coal to obtain energy to meet various needs of human beings, but they will inevitably produce greenhouse gases in the process of use and have an impact on the environment; more importantly, oil and coal are currently identified In terms of the total amount of exploration, the earth will run out of oil and coal in about 200 years, and mankind will face a situation where there is no energy available. A renewable and environment-friendly energy generation method is an urgent problem to be solved by countries all over the world. A sola...

AI Technical Summary

Problems solved by technology

However, due to the 7.2% lattice mismatch between GaAs and InAs, when the number of quantum dot layers reaches a certain number, the strain energy caused by the mismatch will be greatly released, and a large number of dislocations will be generated in the material, making the material sharp deterioration in nature

Although strain compensation barrier technology is currently used in solar cells, such as AlGaNAs or InGaP materials, the number of InAs quantum dot layers can be increased, but in order to avoid the impact of the mismatch between two adjacent layers of quantum dots on the quality of the material, it is required that two adjacent layers The thickness between layers of quantum dots is at least 20 nanometers. Such a large interlayer thickness makes interlayer electron tunneling impossible. Therefore, the conversion efficiency of quantum dot-based intermediate band solar cells is far from reaching theoretical expectations.

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