Bifunctional Precursor‐Assisted Shell Growth and Exciton Dynamics of Highly Luminescent CuInS ₂ /ZnS Quantum Dots

ABSTRACT CuInS ₂ (CIS) quantum dots (QDs) are promising emissive materials due to their eco‐friendly compositions and broadly tunable emission. However, achieving high photoluminescence (PL) performance and elucidating the unusual photophysical properties remain challenging. Herein, we develop a shell‐epitaxy strategy using bifunctional precursors obtained by directly dissolving ZnI ₂ in 1‐dodecanethiol to synthesize CIS/ZnS core/shell QDs, which simultaneously supply monomers for shell growth and generate HI in situ to eliminate surface oxides. The resulting QDs exhibit exceptional optical properties, including a PL quantum yield of ∼90%, monoexponential decay dynamics, and suppressed blinking at the single‐dot level. Combined with emission‐wavelength‐dependent excited‐state dynamics revealed by spectroscopic analysis and energy levels measured by electrochemical studies, we propose a dual‐governed exciton recombination model highlighting the synergistic interplay between band‐edge states and Cu‐related intragap states in CIS‐based QDs. This work sheds new light on the synthesis and exciton dynamics of CIS‐based QDs, pushing ahead toward the development of optoelectronic applications.