Surface-Ligand-Dependent Excited-State Dynamics in Aqueous CuInSe₂/ZnS Quantum Dot–Chlorophyll Assemblies

In this study, CuInSe₂/ZnS quantum dots (QDs) are synthesized via a one-pot aqueous route and interfaced with chlorophyll to investigate ligand-dependent excited-state interactions. The QDs exhibited broad emission between 500–800 nm and long photoluminescence lifetimes with absolute PLQY up to 33.9%. Following the hybridization process, time-resolved photoluminescence (TRPL) is measured. The results indicated a significant reduction in the chlorophyll-like component's lifetime, suggesting dynamic excited-state quenching consistent with Förster-type energy transfer and/or photoinduced charge transfer. Crucially, analysis of lifetime amplitudes uncovered a ligand-dependent partitioning between fast quenched and long-lived QD-associated emissive pathways: short thiol ligands (3-MPA and NAC) strongly suppressed and accelerated the long-lived QD contribution, whereas L-glutathione (L-GSH) progressively restored a dominant long-lived QD-associated component with increasing QD loading. These results support that surface ligand chemistry provides an effective handle to regulate excited-state coupling and emission-pathway partitioning in aqueous QD–chlorophyll hybrid systems.