Electrodeposition Of Cuscn Seed Layers And Nanowires: A Microelectrogravimetric Approach

This paper analyzes the microelectrogravimetric aspects of CuSCN electrochemical deposition. Samples were prepared under conditions typically used during the first preparation step of the increasingly developed inverted photovoltaic cells, i.e., an approach based on the deposition of a hole transporting layer (p-type semiconductor) as a starting film. Here, both CuSCN seed layers and nanowires are the result of an electrodepositon process that uses electrolytes rich in Cu(II) species, thiocyanate ions and additives such as triethanolamine (TEA) or ethylenediaminetetraacetic acid (EDTA). Gold (Au) reactivity was compared to that of Indium Tin Oxide (ITO) coated quartz electrodes in the presence of aqueous thiocyanate ions. Consequently, ITO was confirmed as a suitable substrate for microelectrogravimetric purposes under conditions in which gold becomes electrochemically corroded. Both the speciation and the solubility diagrams for Cu(II) were prepared considering the presence of either TEA or EDTA as additives to establish the possible electroactive species involved in the electrochemical formation of CuSCN and its solubility as it grows. Following a potentiodynamic study and regardless of the additive used, it can be stated that CuSCN is accumulated on the electrode and is then reoxidized. The latter is accompanied by an almost complete loss of the previously accumulated mass. During the elapsed time of the experiments, two Cu(II) insoluble species, namely Cu(SCN)TEA and Cu(SCN)2, were stabilized as colloids in the employed electrolytes. These colloids can also participate as electroactive species in the CuSCN electroformation. However, for a better interpretation of results, more complete speciation diagrams are also required, but thermodynamic information on these species is still not available. During both potentiostatic and galvanostatic CuSCN growth, a CuSCN solubility effect may explain the slightly low faradaic efficiency of this process.