Structural and optical behavior of hexa-propyl methyl cellulose (HPMC) capped ZnS core-shell quantum dots

Abstract

HPMC capped ZnS core-shell quantum dots were synthesized by using simple and eco friendly chemical precipitation method in which HPMC acts as a surface passivator as well as a functionalization agent to tune the properties. Morphological and optical characterizations were done to see the effect of HPMC capping on ZnS quantum dots. Morphological studies was done by using XRD and TEM. XRD studies confirms the pure zinc blende phase for all the samples. TEM studies shows that HPMC is efficiently controlling the agglomeration. Optical studies were done by using UV-visible and FTIR. UV-visible studies shows that bandgap is tunable on both sides of the wavelength depending on the concentration of HPMC. FTIR studies confirms the coating of HPMC on the surface of ZnS quantum dots. Laser induced time resolved photoluminescence studies were also done to see the effect of HPMC on the intensity of excited state life time of quantum dots. It is observed that the structural and optical characteristics have strong dependence on capping concentration. As HPMC is a very important viscoelastic polymer and organic surfactant used in various types of cosmetic binding applications and drug formulations, these studies opens a new way in the area of novel cosmetic design, efficient drug delivery and targeting and also specific optoelectronic applications using chalcogenide quantum dots.