title: Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation.
abstract: Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV-visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10(-8) to 46.5 × 10(-8) mM, with a detection limit of 3.6 × 10(-8) mM.
authors: Central Scientific Instruments Organisation (CSIR-CSIO), Chandigarh-160030, India. sumansingh01@gmail.com
authors: Suman
authors: S
authors: Singh
authors: Sourav
authors: S
authors: Garg
authors: Jitender
authors: J
authors: Chahal
authors: Khushboo
authors: K
authors: Raheja
authors: Deepak
authors: D
authors: Singh
authors: M L
authors: ML
authors: Singla
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D004583:Electrons; D005707:Gallic Acid / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry*; D013696:Temperature
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D011092:Polyethylene Glycols; D005707:Gallic Acid