Controllable indium doping for high efficiency czts thin-film solar cells

Abstract

A photovoltaic device includes a first contact layer formed on a substrate. An absorber layer includes Cu—Zn—Sn—S(Se) (CZTSSe) on the first contact layer. A buffer layer is formed in contact with the absorber layer. Metal dopants are dispersed in a junction region between the absorber layer and the buffer layer. The metal dopants have a valence between the absorber layer and the buffer layer to increase junction potential. A transparent conductive contact layer is formed over the buffer layer.

Description

BACKGROUND[0001]Technical Field[0002]The present invention relates to photovoltaic devices and methods for making the same, and more particularly to a solar cell with doping at a CdS / CZTS interface.[0003]Description of the Related Art[0004]Cu—In—Ga—S / Se (CIGSSe) technology provides high performance solar cells with very high power conversion efficiency (PCE) (e.g., about 20%). CIGSSe solar cells have a very large open circuit voltage (Voc) relative to bandgap with no known issues of interface recombination. Unfortunately the reliance on rare elements, such as indium, for example, limits very large scale deployment of this technology.[0005]Cu—Zn—Sn—S / Se (CZTSSe) is an emerging thin film solar cell technology consisting of all earth abundant elements. While progress has been made in the development of CZTSSe solar cells particularly using hydrazine-based solution processing, a PCE of only about 12.6% has been achieved.[0006]Several major limitations in CZTSSe solar cells exist as well...

AI Technical Summary

Benefits of technology

The patent describes a photovoltaic device with a first contact layer and an absorber layer made of a material called CZTSSe. The device also has a buffer layer made of CdS and metal dopants that enhance the junction potential between the absorber layer and the buffer layer. A transparent conductive contact layer is also included. The device can generate electricity more efficiently and has improved performance.

Problems solved by technology

Unfortunately the reliance on rare elements, such as indium, for example, limits very large scale deployment of this technology.

Several major limitations in CZTSSe solar cells exist as well.

Furthermore, CZTSSe also suffers from low fill factor (FF) which is mostly due to low Voc and higher series resistance from various layers or potential barrier formation across the device.

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