Oxidation kinetics and non-Marcusian charge transfer in dimensionally confined semiconductors

Abstract

Electrochemical reactions represent essential processes in fundamental chemistry that foster a wide range of applications. Although most electrochemical reactions in bulk substances can be well described by the classical Marcus-Gerischer charge transfer theory, the realistic reaction character and mechanism in dimensionally confined systems remain unknown. Here, we report the multiparametric survey on the kinetics of lateral photooxidation in structurally identical WS2 and MoS2 monolayers, where electrochemical oxidation occurs at the atomically thin monolayer edges. The oxidation rate is correlated quantitatively with various crystallographic and environmental parameters, including the density of reactive sites, humidity, temperature, and illumination fluence. In particular, we observe distinctive reaction barriers of 1.4 and 0.9 eV for the two structurally identical semiconductors and uncover an unusual non-Marcusian charge transfer mechanism in these dimensionally confined monolayers due to the limit in reactant supplies. A scenario of band bending is proposed to explain the discrepancy in reaction barriers. These results add important knowledge into the fundamental electrochemical reaction theory in low-dimensional systems.

Lattice Vacancy Induced Energy Renormalization of Photonic Quasiparticles in Two-Dimensional Semiconductors

“…The occurrence of a sustained red shift on hydrophobic substrates upon uninterrupted illumination without any signature of blue shift indicates that the origin is related to the illumination and resultant impacts, rather than simply the positive doping effect as reported. 31 Recently, it has been reported that light illumination can trigger electrochemical oxidation of TMDCs with the absorbed aqueous oxygen, which produces anion vacancies, 32,33 a main degradation mechanism of TMDCs in ambient surroundings. Given the conspicuous PL quenching in experiments, here we propose that the anion vacancies are the factors responsible for the unusual red shift.…”

Spectroscopic Identification of Charge Transfer of Thiolated Molecules on Gold Nanoparticles via Gold Nanoclusters

“…The advancement in modern science and technology is indebted to the development in analytical chemistry, which provides insight into natural phenomena and enables us to understand the basic regularities behind each. , Since many advancements are based on designing hybrid nanostructures, analysis of phenomena that occur in hybrid systems has become a crucial step in their development.…”