The self-assembly of aliphatic thiol (RSH), dithiol (R(SH)(2)), and dithiocarboxylic acid (RS(2)H) onto mildly oxidized and highly oxidized copper was studied in real time by in situ electrochemical impedance spectroscopy (EIS). Ex situ characterization of the films was carried out using linear sweep voltammetry (LSV), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS). In situ EIS studies found a very fast adsorption of RSH, R(SH)(2), and RS(2)H (within 10-15 s). This fast adsorption step is followed by the long-term additional adsorption and consolidation of SAM. However, the self-assembly of RS(2)H passes through an intermediate step of molecule rearrangement for around 10 to 30 min after around 2 to 7 min of self-assembly. The binding of both sulfur moieties of R(SH)(2) with Cu happens simultaneous. The oxide reduction capacity of RSH, R(SH)(2), and RS(2)H was good. However, the XPS studies showed the decomposition of RS(2)H-based SAMs to Cu(2)S. Monolayers prepared on both mildly oxidized and heavily oxidized Cu with R(SH)(2) had the highest stability. Monolayers of RS(2)H showed the least stability on both mildly oxidized and heavily oxidized Cu. Although RSH-based SAMs had good organization on both mildly oxidized and highly oxidized Cu, R(SH)(2)-based SAMs did not show good organization in either case. The RS(2)H monolayer had good organization only on mildly oxidized Cu.

Dye-sensitized photo-rechargeable battery (DSPB) harvests and stores dim light efficiently, realizing indoor-light-harvesting battery to operate IoT devices successfully without sun light.

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Even though electrochemical impedance spectroscopy (EIS) has already been used for the in situ electrochemical study of organothiol self-assembled monolayer (SAM) formation on gold, such studies are not available on oxidizable metals. A scrupulous study of SAM formation on oxidizable metals is a challenge, even by ex situ techniques, because of their highly oxidizable nature and their high interaction with the solvent which are irrelevant with the noble metals. In this report, the self-assembling of n-dodecanethiol, n-dodecaneselenol, didodecyl disulfide, and didodecyl diselenide on copper substrate is studied in real time by in situ electrochemical impedance spectroscopy. The interfacial capacitance variation with time was used to study the adsorption process as a function of time. The selfassembling of n-dodecanethiol and n-dodecaneselenol results in the formation of a layer with coverage of around 90% within 10 s. This fast step happens with an effective removal of the surface copper oxide layer. The second stage involves a long-term additional adsorption and consolidation of the SAM. Didodecyl disulfide is incapable for the effective removal of copper oxide layer, and its adsorption is slow and ineffective. Monolayer formation with didodecyl diselenide takes longer time due to slow copper oxide removal. The in situ EIS results were supported by the polarization modulation infrared reflection absorption spectroscopic (PM-IRRAS) studies.

Stabilizing superoxide (O2 −) is one of the key issues of sodium-air batteries because the superoxide-based discharge product (NaO2) is more reversibly oxidized to oxygen when compared with peroxide (O2 2−) and oxide (O2−). Reversibly outstanding performances of sodium-oxygen batteries have been realized with the superoxide discharge product (NaO2) even if sodium peroxide (Na2O2) have been also known as the discharge products. Here we report that the Lewis basicity of anions of sodium salts as well as solvent molecules, both quantitatively represented by donor numbers (DNs), determines the superoxide stability and resultantly the reversibility of sodium-oxygen batteries. A DN map of superoxide stability was presented as a selection guide of salt/solvent pair. Based on sodium triflate (CF3SO3 −)/dimethyl sulfoxide (DMSO) as a high-DN-pair electrolyte system, sodium ion oxygen batteries were constructed. Pre-sodiated antimony (Sb) was used as an anode during discharge instead of sodium metal because DMSO is reacted with the metal. The superoxide stability supported by the high DN anion/solvent pair ( –/DMSO) allowed more reversible operation of the sodium ion oxygen batteries.