Enhancing luminescence of ZnO quantum dots by PEG and oleic acid via a sol–gel method

Abstract

PEG/oleic acid capped ZnO quantum dots were synthesized by a traditional sol-gel method. The XRD pattern, HRTEM image, FT-IR spectra and photoluminescence properties of the ZnO quantum dots were measured. Viscosities in the reaction with different content of PEG was also measured to discover the way PEG affects the reaction of ZnO quantum dots. PEG and oleic acid could enhance the emission intensity of ZnO quantum dots by cutting down their surface defects. The sample with the content of PEG-400 (n(PEG):n(Zn)) is 1.0:1 and the addition of oleic acid is 2.0 mL (for 0.01 mol ZnO) shows the strongest emission and excitation intensity. However, too much PEG would impede the reaction between Zn(Ac) 2 and LiOH, which leads to the decreasing of the emission intensity.

Adjusting the band structure and defects of ZnO quantum dots via tin doping

“…Under same quantum dot concentration, 15,18 the change in Zn 1Àx Sn x O QDs excitation peaks was connected to the change in Zn 1Àx Sn x O QDs band structures and sizes. 13 For the ZnO quantum dots synthesized under the same condition, the size could be almost the same, meaning the excitation peaks could reect the band structures of Zn 1Àx Sn x O QDs. Fig.…”

Effect of polyethylene glycol and propyltrimethoxysilane on structural and optical properties of zinc oxide nanoparticles synthesized by sol–gel process

“…It has been proposed to add silane to enhance the stability and to prevent ZnO agglomeration. In this case, it would be important that PTMS could protect the surface against agglomeration in the presence of PEG-400, and control their size and photoemission properties [13][14][15][16][17]. A perfect crystal would extend infinitely in all directions, for that reason, no crystal is perfect due to its finite size.…”

ZnO Q-dots as a potent therapeutic nanomedicine for in vitro cytotoxicity evaluation of mouth KB44, breast MCF7, colon HT29 and HeLa cancer cell lines, mouse ear swelling tests in vivo and its side effects using the animal model

“…A mixture of hexamethylenetetramine and triethanolamine in water-ethanol solution was used for amine hydrolysis under vigorous stirring in hot (80 C) and cold (0 C) fast-quenching conditions in the presence of various surfactant templates to obtain polar surface area and very fine nanoparticles. The pH was then adjusted to 8 and stirring was continued under reflux for 9 h. The obtained product was placed in an oven (80 C) for 6 d under hydrothermal process and the solvent was then completely evaporated [9,10,[25][26][27][28][29]. The resulting soya fatty acidcapped ZnO is highly reactive with energetic surfaces.…”