A process for large-scale production of CdTe/CdS thin film solar cells, without the use of CdCl2

Abstract

A process for the large-scale production of CdTe / CdS thin film solar cells, said films being deposited as a sequence on a transparent substrate, comprising the steps of : depositing a film of a transparent conductive oxide (TCO) on said substrate; depositing a film of CdS on said TCO film; depositing a film of CdTe on said CdS film; treating said CdTe film with a Chlorine-containing inert gas; depositing a back-contact film on said treated CdTe film. The Chlorine -containing inert gas is a Chlorof luorocarbon or a Hydrochlorof luorocarbon product and the treatment is carried out in a vacuum chamber at an operating temperature of 380-4200C. The Chlorine released as a result of the thermal dissociation of the product reacts with solid CdTe present on the cell surface to produce TeCl2 and CdCl2 vapors. Any residual CdCl2 is removed from the cell surface by applying vacuum to the vacuum chamber while keeping the temperature at the operating value.

Description

technical field [0001] The present invention relates to the field of solar cell technology, and more particularly, to methods for the mass production of CdTe / CdS thin film solar cells. More specifically, the present invention relates to the improvement of the processes involved in the activation of CdTe / CdS thin films by chlorine-containing gases. Even though in this specification reference is made to "CdTe / CdS thin film" solar cells for simplicity, it will be understood that this term is included in the formula Zn x ,Cd 1-x S / CdTe y S 1-y All salt mixtures contained in , where 0≤x≤0.2 e 0.95≤y≤1. Background technique [0002] It is well known that the typical structure of a CdTe / CdS solar cell has a multi-layered film sequence, including a transparent glass substrate carrying a transparent conductive oxide (TCO) film, a Cds film representing an n-conductor, a CdTe film representing a p-conductor, and a metal rear. contacts. A solar cell with a layer arrangement and a ...

AI Technical Summary

Problems solved by technology

The above steps greatly affect the production cost

[0014] As another disadvantage, since CdCl 2 Usually available as a very fine powder, it cannot be evaporated in a straight line on an industrial production line, because the finest particles in the vapor will cause local uneven deposition

For this, the CdCl must be sintered in the form of an ingot before evaporation 2 powder, which is a very expensive step given the safety precautions considered when performing

[0015] Furthermore, usually, CdCl 2 Handling and storage has several disadvantages

CdCl 2 Has a relatively low evaporation temperature (approximately 500°C in air) and is dangerous in fire situations due to the very harmful release of Cd when stored in large quantities as required in large-scale production plants

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