Au Nanocluster/CdTe Quantum Dot-Based Hybrid Quantum Cluster Dots for Energy Transfer-Driven Fluorescence Enhancement and Charge Transport: Implications for Bioimaging and Optoelectronic Applications

Achieving stable hybrid architectures from different fluorescent nanomaterials is an underexplored domain that demands precise modulation of interfacial energy transfer and surface interactions, which is particularly challenging at the nanoscale. Herein, we address this gap by presenting the synthesis and comprehensive characterization of a fluorescent entity termed quantum cluster dots (QCDs), meticulously engineered by integrating two fluorescent nanomaterials, GSH AuNCs and MPA CdTe QDs. The synthesis was systematically optimized by varying the molar ratios of Cd (from CdTe QDs) and Au (from AuNCs), revealing an ideal stoichiometry of Au:Cd = 1:0.16 as the most stable and highly fluorescent formulation. Multidisciplinary characterization (HR-TEM, XPS, zeta potential, TGA, FT-IR, EDX, PXRD, and fluorescence spectroscopy) revealed modified optical/surface properties and confirmed stable electrostatic assembly between cationic AuNCs and anionic CdTe QDs. At the AuNCs excitation wavelength, enhanced AuNCs emission indicates efficient energy transfer from the QDs to the NCs. The XPS analysis revealed relatively weak Cd and Te signals, indicating gold accumulation on the surface, partially masking the CdTe core. Notably, this is the first report that thoroughly discusses the fabrication of the surface-passivated hybrid system (Au-CdTe QCDs) that has promising potential for exploring newer avenues as bioimaging probes and charge-transport platforms in next-generation optoelectronic devices.