The activation process using chlorine compounds is considered an important issue in CdTe solar cells technology. For a long time researchers have tried to replace the most successful CdCl2 activator with a non-toxic compound more suitable for industrial production. In the last years many alternatives were presented, among them the most promising is the MgCl2. In this work we study the CdTe activated using MgCl2 solution. Its chemical, physical and electrical transformations were deeply investigated. FESEM, EDS, XRD, and XPS characterization bring out the presence of MgO and residues of another's oxides on the CdTe surface. The impact of these oxides on the solar cell performance was studied by EQE, J-V, C-V and DLCP. The solar cell activated with MgCl2 had an efficiency of 12.5%; the V-oc, J(sc) and FF were 831 mV, 23.3 mA/cm(2) and 64.5%, respectively, in a device with an area of 0.5 cm(2). (C) 2017 Elsevier Ltd. All rights reserved.