Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells Lan Wang, Xianzhong Lin, Ahmed Ennaoui, Christian Wolf, Martha Ch. Lux-Steiner and Reiner Klenk EPJ Photovolt., 7 (2016) 70303 Published online: 26 February 2016 DOI: 10.1051/epjpv/2016001