title: CdSe and CdSe/CdS core-shell QDs: New approach for synthesis, investigating optical properties and application in pollutant degradation.
abstract: In this work, CdSe quantum dots (QDs) were synthesized by a simple and rapid microwave activated approach using CdSO4, Na2SeO3as precursors and thioglycolic acid (TGA) as capping agent molecule. A novel photochemical approach was introduced for the growth of CdS QDs and this approach was used to grow a CdS shell around CdSe cores for the formation of a CdSe/CdS core-shell structure. The core-shells were structurally verified using X-ray diffraction, transmission electron microscopy and FTIR (Fourier-transform infrared (FTIR)) spectroscopy. The optical properties of the samples were examined by means of UV-Vis and photoluminescence (PL) spectroscopy. It was found that CdS QDs emit a broad band white luminescence between 400 to 700 nm with a peak located at about 510 nm. CdSe QDs emission contained a broad band resulting from trap states between 450 to 800 nm with a peak located at 600 nm. After CdS shell growth, trap states emission was considerably quenched and a near band edge emission was appeared about 480 nm. Optical studies revealed that the core-shell QDs possess strong ultraviolet (UV) - visible light photocatalytic activity. CdSe/CdS core-shell QDs, showed an enhancement in photodegradation of Methyl orange (MO) compared with CdSe QDs.
authors.affiliation: Department of Physics, Faculty of Science, Vali-e-Asr University, Rafsanjan, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Abbasi
authors.affiliation: Department of Physics, Faculty of Science, Vali-e-Asr University, Rafsanjan, Iran.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-4129-7328
authors.initials: M
authors.lastname: Molaei
authors.affiliation: Department of Physics, Faculty of Science, Vali-e-Asr University, Rafsanjan, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Karimipour
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D019187:Cadmium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D008872:Microwaves; D010782:Photolysis; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013440:Sulfides / Q000138:chemical synthesis / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001391:Azo Compounds; D019187:Cadmium Compounds; D004785:Environmental Pollutants; D007202:Indicators and Reagents; D018036:Selenium Compounds; D013440:Sulfides; C034939:cadmium sulfide; C100258:methyl orange; C058667:cadmium selenide
keywords: CdSe/CdS; optical properties; photocatalytic; quantum dots