| Abstract | This work reports the synthesis of CdS nanoparticles (NPs) capped with ammonia and triethylamine by
using a precipitation method. The obtained particleswere characterized by using X-ray diffraction (XRD),
transmission electron microscope (TEM) and spectroscopic techniques. The particle size for NPs capped
with ammonia (6.2 nm) and triethylamine (2.4 nm) was calculated from XRD patterns using Scherrer
formula. For ammonia capping, the optical properties are typical of localized surface states. However,
the confinement effects play a significant role in the optical properties of triethylamine capping. The
emission of CdS NPs is quenched by Flufenamic acid (FLF) drug. At pH 7, the quenching efficiency of
triethylamine capped CdS NPs is greater than that of ammonia capping. The interaction between FLF
and ammonia capped CdS NPs proceeds via electrostatic mode, whereas for triethylamine capping the
interaction might be due to electron transfer process. In acidic media, the fluorescence quenching of
ammonia capped CdS in the presence of FLF was followed by a fluorescence enhancement and blue shift
of fluorescence emission. This might be a result of the dissociation of the CdS-ammonia nanosystem, due
to protonation of the surface. In such case, removing the capping agent, leads to faster aggregation of the
particles. |