Optical properties of colloidal CdSe/CdS/Zns/PVPQDs core/ shellsembedded in fatty acid medium

Author(s): M.A.Batal,KaesarAl-yamani

Colloidal solutions of CdSewere prepared in fatty acidat room temperature. The prepared samples were coated with CdS, ZnS semiconductors shells. Absorption and fluorescencespectrum were measured. From absorption spectra the diameter of CdSe QDs and energy bandgap were calculated using hyperbolic approximation and some empirical equations. The diameter ofQDs were less than (2)nm and increase with ageing time reaching to 5 nm. CdSe QDs coated with moresemiconductors shells (CdSe/CdS,CdSe/ZnS, CdSe/CdS/ZnS) were prepared too. Also the system CdSe / CdS / ZnS / PVP[Core / shell / shell / shell] were prepared, that increase fluorescenceintensitywith more diluted by fatty acid. Finally, quantum confinement increase when the number of semiconductor shells increase.

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