Fluorescence Resonance Energy Transfer Study Between ZnS Quantum Dots and Fluoranthene

Abstract

Single‐phase zinc sulphide (ZnS) quantum dots were synthesized by hydrothermal method without using any capping agent. X‐ray power diffraction, transmission electron microscopy, and ultraviolet‐visible spectroscopy were used to characterize the structure, size, surface states. Photoluminescence properties of ZnS quantum dots were studied to apply it as fluorescence sensor. The results showed that the crystal structure of ZnS quantum dots was a cubic zinc blende, and their average diameter was about 3.5 nm. A strong broad band cantered at about 320 nm was observed in the excitation spectrum of ZnS quantum dots. Their emission spectrum peaking at about 408 nm, was due mostly to the trap‐state emission. We used cadmium as fluorescence super quencher to detect the presence of cadmium. The relative integrated emission intensity of ZnS quantum dots decreased as the amount of Cd increased. That 408 nm emitted radiation was then used to detect the presence of fluoranthene, a potential carcinogen, present in solution. The novelty of the process is the use of water as a solvent for synthesis, without using any capping agent by slow hydrothermal process.