18% efficiency Cd-free Cu(In, Ga)Se2 thin-film solar cells fabricated using chemical bath deposition (CBD)-ZnS buffer layers

Cadmium-free hi-fi efficiency Cu(In, Ga)Se-2 (CIGS) thin-film solar cells have been fabricated using chemical bath deposition (CBD)-ZnS buffer layers. The use of CBD-ZnS, which is a wider band gap material than CBD-CdS, improved the quantum efficiency at short wavelengths, resulting in an increase in the short circuit current of fabricated solar cells. The best cell at present yielded art active area efficiency of 18.1%, which is the highest value reported previously for CIGS thin solar cells with alternative buffer layers to CdS.