Nucleation and Growth of ZnO Nanorod Arrays onto Flexible Substrates

The role of the applied potential to the electrodeposition process of ZnO onto flexible polymeric substrates was investigated. ZnO nanostructures were prepared on indium-tin oxide conducting flexible substrates, using the electrodeposition method at 70 degrees C in a zinc nitrate electroplating bath for different deposition potential, E-dep, which has been divided in three distinct regions named as A, B and C. Chronoamperometric analysis reveals that the nucleation growth mechanism is strongly affected by the deposition conditions. The analysis of the current time transients indicates that the ZnO electrodeposition occurs by progressive three-dimensional nucleation with diffusion-controlled growth in region B, -1000 < E-dep < -1200 mV. For -700 < E-dep <-1000 mV (region A), it is assumed that the electrodeposition process is mainly controlled by the slowest kinetic electroreduction of dissolved oxygen and nitrate ions resulting a low nucleation rate. Furthermore, in region C, related to more negative applied potentials, the electrodeposition process is conditioned by the substrate stability. The kinetic parameters values obtained from the diffusion controlled model are in good accordance to the dimensionless analysis of the transients. X-ray diffraction analysis confirmed the formation of (002) textured ZnO structures prepared in regions B and C. (C) 2013 The Electrochemical Society. All rights reserved.