Promising Electrochemiluminescence from CuInS 2 /ZnS Nanocrystals/Hydrazine via Internal Cu(I)/Cu(II) CoupleCycling

Screening novel electrochemiluminescence (ECL) system is crucial to ECL evolution. Herein, an efficient ECL system with less interference and environmental concern under physiological condition is developed via a unique internal Cu(I)/Cu(II) couple cycling amplified strategy by employing the glutathione- and citrate-capped copper indium sulfide (CIS)/ZnS nanocrystals (NCs) as electrochemiluminophore and N2H4·H2O as co-reactant. The CIS/ZnS NCs can be electrochemically injected with valence band (VB) hole at 0.46 V and 0.87 V (vs Ag/AgCl), and then achieve the same hole-injected states by re-localizing VB holes with the Cu(I) species inside of CIS/ZnS NCs to form internal Cu(II) defects, while each N2H4·H2O molecule can be successively oxidized to two more reducing species N2H3• and N2H2 around 0.10 V, and inject conduction band (CB) electron onto CIS/ZnS NCs for triple times. The internal Cu(I)/Cu(II) couple cycling involved radiative-charge-recombination between these VB hole and CB electron eventually e...