Copper Sulfide Nanocrystal Level Structure and Electrochemical Functionality towards Sensing Applications

Abstract

The level structure of copper sulfide nanocrystals of different sizes was investigated by correlating scanning tunneling spectroscopy and cyclic voltammetry data in relation to sensing applications. Upon oxidation of Cu2 S nanocrystals in the low-chalcocite phase, correlated changes are detected by both methods. The cyclic voltammetry oxidation peak of Cu(1+) down shifts, while in-gap states, adjacent to the valence-band edge, appeared in the tunneling spectra. These changes are attributed to Cu vacancy formation leading to a Cu depleted phase of the nanocrystals. The relevance of the oxidation to the use of copper sulfide nanocrystals in hydrogen peroxide sensing was also addressed, showing that upon oxidation the sensitivity vanishes. These findings bare significance to the use of copper sulfide nanocrystals in glucose sensing applications.

Plasmonic doped semiconductor nanocrystals: Properties, fabrication, applications and perspectives

“…p-type doping. [154] In parallel to this, there are progressive changes in the crystal structure towards lower Cu stoichiometries (Figure 17).…”

Shape Control of Colloidal Cu2–xS Polyhedral Nanocrystals by Tuning the Nucleation Rates

“… 14 , 15 Moreover, Cu 2– x A NCs can hold both excitons and tunable localized surface plasmon resonances on demand. 9 , 13 , 16 − 18 This makes Cu 2– x A NCs promising materials for photovoltaics, 15 photocatalysis, 19 sensing, 20 and nanoplasmonics. 9 , 11 , 17 , 21 , 22 …”

Size Dependence of Doping by a Vacancy Formation Reaction in Copper Sulfide Nanocrystals

“…Copper sulfide and other copper chalcogenide NCs have been widely studied in recent years owing to their reduced toxicity, environmental compatibility and their relevant band-gap for photovoltaic applications (1.21eV for bulk Cu2S). [23][24][25][26][27][28][29] Doping via Cu vacancy formation occurs readily due to the low chemical potential and high mobility of copper ions. [30] This transforms the stoichiometric Cu2S phase to Cu depleted Cu2-xS phases, also possibly undergoing structural transformation.…”