Effect of Cu content and temperature on the properties of Cu2ZnSnSe4 solar cells Sylvester Sahayaraj, Guy Brammertz, Marie Buffière, Marc Meuris, Jef Vleugels and Jef Poortmans EPJ Photovolt., 7 (2016) 70304 Published online: 23 September 2016 DOI: 10.1051/epjpv/2016004