Thin-film solar cell

Abstract

The present invention relates to thin-film solar cells of the CIGS-type. A characteristic feature of the invention is the use of two integrally formed buffer layers, a first ALD Zn(O,S) buffer layer (7) on top of the CIGS-layer (3) and a second ALD ZnO-buffer layer (8) on top of the first (7) buffer layer. Both buffer layers are deposited in the same process step using ALD (atom layer deposition). The invention also relates to a method of producing the cell and a process line for manufacturing of the cell structure.

Description

TECHNICAL AREA [0001] The present invention relates to a thin-film solar cell without cadmium, to a method and production line for manufacturing such cells. BACKGROUND OF THE INVENTION [0002] Solar cells provide a means to produce electric power with minimal environmental impact because it is a renewable technology. In order to become a commercial success the solar cells need to be efficient, to have low cost, to be durable, and not add other environmental problems. [0003] Today's dominant solar cell technology is based on crystalline silicon. It fulfils many of the requirements mentioned above but can not be produced at such low cost that electricity generation in large scale is cost effective. It also requires relatively large amount of energy in the production, which is an environmental disadvantage. [0004] Solar cells based on thin film technologies have been developed. They offer a potential of substantial cost reductions but have, in general, lower conversion efficiencies and ...

AI Technical Summary

Benefits of technology

[0017] One object of the invention is to reduce the number of process steps for the manufacture of the solar cell, thereby reducing the cost involved in their manufacture.

[0019] Still another object of the invention is to replace the CdS-layer with a material that absorbs less of the incident light than does a CdS-layer, thereby increasing the amount of light impinging the under-laying CIGS-layer and accordingly increasing the photo current generated by the cell.

Problems solved by technology

It fulfils many of the requirements mentioned above but can not be produced at such low cost that electricity generation in large scale is cost effective.

It also requires relatively large amount of energy in the production, which is an environmental disadvantage.

They offer a potential of substantial cost reductions but have, in general, lower conversion efficiencies and less good durability.

To fabricate the solar cell with chemical wet process steps mixed with sputtering makes the solar cell less attractive for large scale production.

To fabricate the solar cell wet processes are mixed with the co-vapour deposition process which renders the structure less attractive for large scale production.

To manufacture the solar cell with chemical wet process steps mixed with sputtering makes the solar cell less attractive for large scale production.

The use of toxic cadmium makes the cell less attractive for environmental reasons.

Also handling and disposal of the hazardous wastes are costly.

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