Polycrystalline Cu2ZnSnS4 thin films were electrodeposited on Mo and F:SnO2/Glass substrates at room temperature by single step method from an aqueous solution containing tri-sodium citrate and tartaric acid as complexing and pH controlling agents, respectively. The thermostatic bath deposition was carried out at room temperature (25 degrees C) with lower and higher initial concentrations of Cu, Zn, Sn and S-precursors in order to investigate the effect of stoichiometric deviations on their phase compositions and optoelectronic properties. As-prepared samples were photoactive as revealed by photo electrochemical (PEC) measurement, however, it showed the films were mixture of p- and n-type semiconducting phases. The post-annealing treatment was carried out in the temperature range 400-600 degrees C in an Ar-atmosphere to improve the CZTS phase composition and crystallinity of the film. The kesterite Cu2ZnSnS4 phase with preferred orientation along the (112) crystal direction grew to greater extent upon Ar-annealing at 500 degrees C associated with an improvement in the optical band gap. The PEC cells made from the annealed film showed an enhanced photocurrent response with p-type conductivity. (C) 2015 Elsevier B.V. All rights reserved.