Tailoring Photoluminescence Properties of Ternary Zn‐doped Cu─In─Se Quantum Dots via Surfactant Tuning

Abstract The shape and size‐controlled synthesis of colloidal I−III−VI quantum dots (QDs) can be attained only by a few synthesis strategies via the introduction of various high‐boiling‐point organic surfactants. To further investigate this strategy, in this study, we present a surfactant‐associated controlled synthesis of copper (Cu)‐deficient, zinc (Zn)‐doped Cu─indium (In)─selenium (Se) QDs, followed by a mechanistic investigation of their photophysical properties using surfactants, such as oleylamine (OLA), oleic acid (OA), and diphenylphosphine (DPP). OLA significantly promoted the quantum size effect‐resultant emission wavelength red‐shift, while OA controlled the homogeneous growth of QDs and improved the quantum yields. Moreover, Gaussian deconvolution of the photoluminescence spectra and the bandgap derived from the absorption spectra, by fitting, supported the fact that the radiative transition channels, especially for surface‐trap‐state‐related transitions, are also dependent on the surfactants. Specifically, the conduction band electron‐intragap state transitions and donor‐acceptor transitions were present in all the prepared samples but accounted for different percentages. Furthermore, the surface‐trap‐state‐related transitions significantly faded upon adding (i) OLA/OA as the sole surfactant to the cationic precursor and (ii) the OA + OLA + DPP mixture to the anionic precursor. The findings described here are expected to provide a general strategy for enhancing the tunability of photophysical properties in other QDs systems.