Abstract
Cathodic electrodepositon of CuSCN thin films on F-doped SnO2 (FTO) substrates has been investigated in aqueous mixed solution of copper perchlorate and lithium thiocyanate. Cathodic current arose around +0.5 V vs. Ag/ AgCl and reached a plateau below ca. +0.3 V in the mixed solution. Levich analysis of the plateau current confirmed limitation of CuSCN deposition by mass transport. The current was proportional almost symmetrically to the concentrations of Cu2+ and SCN-, suggesting that transport of their complex was responsible. Absorption spectrum of the mixed solutions indeed revealed an appearance of a new peak only when both Cu2+ and SCN- were present. Job plot for this peak elucidated formation of 1 to l complex. As the concentration of this active species could be determined from the absorption spectra, Levich analyses at different temperatures made it possible to determine the frequency factor (Do) of and the activation energy (Ea) for the diffusion of (Cu2+)(SCN-) complex as 3.24 x 10-2 cm2 s-1 and 20.1 kJ mol-1 , respectively.
