Structure–Property Relationship between Heterometal Ions and Hot Electron Relaxation in Colloidal Quantum Dots

The structure and physical properties of materials, such as elementary exciton processes, are closely interrelated. Doping copper ions in colloidal semiconductor quantum dots (QDs) has been shown to suppress hot electron relaxation. However, the relationship between the local environment of the heterometal ions in the host crystal and the physical properties has been insufficiently explored. In this study, CdSe and InP QDs were synthesized in the presence of heterometal ions. Copper ions were doped into CdSe QDs and segregated into InP QDs, as confirmed by X-ray absorption fine structure measurements, leading to hot electron relaxation being suppressed only in the CdSe QDs. On the basis of these findings, we developed a design strategy and successfully suppressed hot electron relaxation in InP QDs by introducing chromium ions. Understanding the local structure of dopants in QDs is essential for elucidating their physical properties and enabling the rational design of dopants to achieve novel functionalities.