On the Contrasting Effect Exerted by a Thin Layer of CdS against the Passivation of Silver Electrodes Coated with Thiols

Abstract

Abstract:The passivation of metal electrodes covered by self-assembled monolayers of long-chain thiols is well known. The disappearance of the voltammetric peak of redox species in solution is a classical test for the formation of full layers of thiols. Similar studies on semiconductors are still very limited. We used silver surfaces covered by an ultrathin layer of CdS as substrate for self-assembling of n-hexadecanethiol (C 16 SH), and we compared the experimental results with those obtained by using the bare silver surface as substrate. The strong insulating effect of C 16 SH deposited on Ag(III) is shown by the inhibition of the voltammetric peak of Ru(NH 3 ) 6 3+/2+ . On the contrary, the voltammogram obtained on CdS-covered Ag(III) is very similar to that obtained on the bare Ag(III) electrode, thus suggesting that the presence of CdS exerts a contrasting effect on the passivation of the silver electrode. A crucial point of our work is to demonstrate the effective formation of C 16 SH monolayers on Ag(III) covered by CdS. The formation of full layers of C 16 SH was strongly suggested by the inhibition of the stripping peak of Cd from the CdS deposit covered by C 16 SH. The presence of C 16 SH was confirmed by electrochemical quartz crystal microbalance (EQCM) measurements as well as by Auger electron spectroscopy (AES) analysis.

Chiral “doped” MOFs: an electrochemical and theoretical integrated study

“…The GCE/MOF served as the working electrode (WE), while a coiled Pt wire and an Ag/AgCl (saturated KCl) electrode served as the counter (CE) electrode and reference electrode (RE), respectively. The special flat-cell configuration of the cell, developed in the past for ECALE depositions ( Forni et al, 2000 ; Innocenti et al, 2001 ; Giurlani et al, 2018 ; Salvietti et al, 2018 ; Giurlani et al, 2020 ) and adapted for solid-state measurements, features the working electrode placed at the bottom, to help maintaining the graphite-powder/MOF mixture in position. A suitable arrangement was adopted ( Supplementary Figure S1 ), a cylindrical Teflon cell featuring a hole (7 mm diameter) in the bottom was used in a vertical configuration, where the glassy carbon electrode (GC) (1.5 cm diameter) was tightened from below.…”

Optimization and Characterization of Electrodeposited Cadmium Selenide on Monocrystalline Silicon

“…The semiconductor nature of Si makes finding the right deposition conditions a difficult task since the exchange of electrons between the electrode and the solution is severely limited compared to metal electrodes and is influenced by the lighting conditions. While the deposition of CdSe on metals is now a well-known practice in the scientific field [36][37][38][39], as well as other semiconductors (CdS [40], MoSe 2 [41], Bi 2 Se 3 [42]), its deposition on Si has been scarcely explored.…”