Engineering a Ga-Gradient by One-Step Sputtering to Achieve Over 15% Efficiency of Cu(In,Ga)Se Flexible Solar Cells without Post-selenization.

A one-step sputtering process using a quaternary target has been demonstrated to be a simple route to form Cu(In,Ga)Se (CIGSe) absorber without post-selenization; however, the lack of a Ga-grading structure in the CIGSe absorber confines its efficiency. Here, we demonstrate a one-step cosputtering process to control the Ga profile in the CIGSe absorber on flexible stainless steel substrates. Special attention was paid to the formation of second phases and their effects on the cell performance.

Efficiency Enhancement of Cu(In,Ga)(S,Se) Solar Cells by Indium-Doped CdS Buffer Layers.

Improving power conversion efficiency of photovoltaic devices has been widely investigated; however, most research studies mainly focus on the modification of the absorber layer. Here, we present an approach to enhance the efficiency of Cu(In,Ga)(S,Se) (CIGSSe) thin-film solar cells simply by tuning the CdS buffer layer. The CdS buffer layer was deposited by chemical bath deposition.