Low-cost, non-toxic and efficient material is an urgent need for the thermoelectric energy conversion. Here, a rapid and ambient chemical route has been developed to grow dense and highly oriented dendrites of copper sulfide (Cu2S) on copper substrate in a very simple approach, these films are uniform and covered with dense nanosheets. Room temperature solution doping of copper ions is carried out to improve thermoelectric performance. The Seebeck coefficient increased from similar to 100 to 415 mu VK-1 with a slight decrease in electrical conductivity, this gives a high power factor (S-2 sigma) of about similar to 400 W m(-1) K-2. The improved thermoelectric properties in these films are accounted for resonant energy level doping and high phonon scattering. Such films with improved thermoelectric behaviour can be promising materials for energy conversion. The earth abundant, low cost, non toxic with a good thermoelectric property makes copper sulfide as a promising thermoelectric material for future applications. (C) 2016 Elsevier B.V. All rights reserved.