Synergistic Enhancement of Fluorescence Through Plasmon Resonance and Interfacial Charge Transfer by AgNC@AgAu_x Core–Shell Quantum Dots

Bimetallic core–shell quantum dots (QDs) hold great promise in elucidating the bimetallic synergism and optoelectronic devices. The synthesis and properties of AgNC@AgAu_x QDs of core–shell heterostructure are reported. Significantly enhanced photoluminescence emission on these heterostructures is observed. These enhancements are attributed to electron injection and the surface plasmon-induced strong local electric field, which are observed through time-resolved transient absorption spectroscopy. X-ray absorption near edge structure spectra and density functional theory confirms the electron injection from the Ag core to the AgAu_x shell. On the other hand, the plasmon resonance of the AgNC@AgAu_x QDs has been studied by finite-element method analysis and time-resolved photoluminescence spectra. There are 94.06 times fluorescence enhancement and 32.40 times quantum yield improvement of oxygen content correlation compared to AgAu₃ QDs. It shows a perfect correlation coefficient of 98.85% for the detection of heavy metal Cu²⁺ ions. Such Bimetallic core–shell heterostructures have great potential for future optoelectronic devices, optical imaging, and other energy-environmental applications.