Low cost techniques for the preparation of Cu(In,Ga)(Se,S)2 absorber layers

Abstract

The group of chalcopyrite semiconductors in the Cu(In,Ga)(Se,S)2 or CIGSS family synthesized by vacuum techniques have been successfully used in the fabrication of high efficiency thin film solar cells. This paper concentrates on a group of low cost, non-vacuum approaches that are highly promising as alternative methods of preparing chalcopyrite absorbers for thin film solar cell applications. Techniques which are based on ‘particle deposition’ fix the metal ratios in a source material containing sub-micron size particles and then transfer this fixed composition onto large area substrates. In this contribution we present data on nano-particle deposition techniques that yielded chalcopyrite absorbers for the fabrication of over 10% efficient solar cells. Mini-modules with over 7% efficiency have also been fabricated using these low cost approaches.