Present investigation focused on the fundamental understanding regarding the tailoring of photovoltaic (PV) device efficiency of 3D-CdS nanonetwork through annealing with the aid of electrochemical studies. The synthesis of CdS nanowires (NWs) have been performed using Cd(OH)(2) NWs as intermediate sacrificial templates based on negative free energy of formation. The changes in structure, morphology and optical properties of CdS by annealing have been studied. The enhancement in crystallite size by annealing was correlated to the negative shift of the conduction band position, charge transport and electron life time towards PV performance. These have been performed by studying lattice parameters which in turn correlated to the capacitance, external quantum efficiency and impedance analysis through light-induced electrochemical studies. (C) 2016 Elsevier Ltd. All rights reserved.