Cu2ZnSnSe4 films were prepared by selenization of metallic precursors obtained by a new wet process involving metal formates. Cu(HCOO)(2) and Zn(HCOO)(2) were used as copper and zinc sources respectively, while tin was introduced as a methoxide. The elemental analysis of the resulting absorber layers revealed a very low carbon content (less than 0.2 wt%), which is believed to be a feature that chemical methods need to have in order to stand out as valuable alternatives to high-vacuum processes in this field. Solar cells with efficiencies of up to 2.39% with V-oc of 207 mV, a J(sc) of 31.2 mA/cm(2) and a fill factor of 37.1% were achieved for these copper-poor CZTSe absorbers. (c) 2015 Elsevier Ltd. All rights reserved.