A transparent nanocrystalline Cu2O thin film has been synthesized by electrodeposition using a reverse potential waveform with a cathodic peak potential of -1200mV, an anodic dissolution peak potential of + 800 mV and a cycle time of 80s. For each cycle, Cu2O particles are firstly deposited on the substrate, followed by the deposition of Cu particles. When the current changes from cathodic to anodic, the deposited Cu particles will be dissolved. With repeated cyclic deposition and dissolution, a Cu2O thin film with nanocrystallized structure is obtained, and it exhibits a blueshift of optical bandgap to 2.87 eV. (C) 2013 Elsevier B. V. All rights reserved.