Novel electrochemically approach for probing in situ self-assembly by tracking shift of I–E curve of Ohmic circuit

A novel electrochemically approach for in situ probing the self-assembly is proposed by tracking the shift of the I–E curve of an Ohmic circuit. In the proposed approach, the external electrolysis circuit of three-electrode potentiostat is re-equipped to be an Ohmic circuit by connecting in series a conductive substrate between two clips of working and counter electrodes, and a reference electrode is still connected with the clip of reference electrode. Moreover, the conductive substrate and the reference electrode are immersed in a supporting electrolyte containing adsorbate, a linear sweep potential with respect to the reference electrode is applied to the substrate, at the same time an I–E curve is recorded. With the self-assembly processing, interfacial potential at the substrate/solution interface gradually changes, resulting into the gradual shifts of the recorded I–E curves along potential axis. The shift of the I–E curve is confirmed by employing zero current potential Ezcp that circuit current I is equal to zero in the I–E curve. Tracking the shift of zero current potential Ezcp can probe in situ the self-assembly continuously. Herein, the fundamental of the proposed approach is illustrated briefly and the self-assembly of l-cysteine on the gold surface as an example is probed by the proposed approach. The obtained results showed the proposed approach is very simple, rapid and sensitive.