Redox Reactions at Colloidal Semiconductor Nanocrystal Surfaces

The adaptation of colloidal semiconductor nano-crystals (NCs) in applications like displays, photovoltaics, and photocatalysis relies primarily on the core electronic structure of NC materials that give rise to desirable optoelectronic properties like broad absorption and size-tunable emission. However, reduction or oxidation events at localized NC surface sites can greatly affect sample stability and device efficiencies by contributing to NC degradation and carrier trapping. Under-standing the local composition, structure, and electrochemical potentials of redox-active NC surface sites continues to present a challenge. In this perspective, we discuss how NC surface reduction, oxidation, and electrostatics contribute to NC electronic properties that include photoluminescence quenching or brightening and shifts in NC band edge potentials, among others. Recent efforts toward combining spectroscopic, electrochemical, and computational methods to characterize redox-active surface sites and trap states are highlighted, including developing methods in the field and future opportunities.

Automated summary

This perspective discusses how reduction, oxidation, and electrostatics on the surface of colloidal semiconductor nano-crystals (NCs) contribute to their electronic properties, including photoluminescence quenching or brightening and shifts in band edge potentials. It highlights recent efforts in combining spectroscopic, electrochemical, and computational methods to characterize redox-active surface sites and trap states and explores future opportunities in this field.