CIGS solar cell with Cd-free buffer layer and method for preparing same

Abstract

The invention discloses a solar cell with a Cd-free buffer layer and a method for preparing the same. The solar cell comprises a substrate, a back electrode layer, a CIGS absorption layer, a buffer layer, a transparent conductive layer and a top electrode. The buffer layer is Zn-based compound Zn(S, O). The buffer layer uses Zn-based compound and no Cd participates in a production process, therebybeing friendly to environment and reliable. The buffer layer uses Zn(S, O), has a wide band gap, and can effectively utilize sunlight to increase current density and thereby increase battery efficiency. The production process of the buffer layer matches the production process of other film layers, and belongs to a vacuum dry method, which improves production efficiency, is favorable for large-scale production, and improves production capacity.

Description

technical field [0001] The invention belongs to the field of thin-film solar cells, in particular to a copper (Cu) indium (In) gallium (Ga) selenium (Se) (abbreviation: CIGS) solar cell with a Cd-free buffer layer and a preparation method of the solar cell. Background technique [0002] A solar cell is a semiconductor functional device that directly converts sunlight energy into electrical energy through the photoelectric effect or photochemical effect. Since Wanger et al. prepared the world's first CIS thin-film solar cell in 1974, CIS / CIGS solar cells have stable performance under sunlight exposure, strong radiation resistance, large room for improvement in conversion efficiency, and can be deposited on flexible substrates. Superior advantages have attracted extensive attention from researchers in the photovoltaic industry. [0003] CIGS thin-film solar cell is a photovoltaic device formed by depositing multiple layers of thin films on glass or other cheap substrates. Th...

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Problems solved by technology

First of all, Cd in the CdS buffer layer material is a heavy metal, which is a toxic substance. The discharge of Cd-containing wastewater during the production process and the loss of Cd in scrap batteries will cause environmental pollution and have certain hazards to the operator; secondly, the forbidden band of CdS The width is 2.4-2.5eV, which will absorb high-energy photons of 350-550nm in the solar spectrum, resulting in optical loss, which is not conducive to the full utilization of sunlight by the absorbing layer; again, the CdS buffer layer adopts a chemical water bath method, and the wet preparation process is the same as The dry preparation process of other layers of CIGS solar cells does not match, which is not conducive to large-scale assembly line production, with low production efficiency and high cost

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