Quantum dots are nanocrystals, composed of semiconducting material, that fluoresce at various tunable emissions in accordance with their particle size. Quantum dots are unique in comparison to other fluorescent materials because the wavelength of light emitted is dependent upon their size. Quantum dots that emit more blue-shifted wavelengths of light tend to be significantly smaller compared to quantum dots that emit more red-shifted wavelengths of light. Quantum dot’s light-emitting properties have been studied for use in various applications such as solar cells, optical amplifiers, photodetectors, solar cells, and lasers. However, the purpose of our research is to synthesize stable quantum dots, composed of a zinc oxide core, with relatively cheap and nontoxic materials. Overtime, quantum dots increase in size which leads to more red-shifted fluoresce and instability. Our goal is to successfully stabilize these quantum dots using poylethylenimine (PEI) as a surface modifier to inhibit aggregation and growth. After initial synthesis, their growth was monitored daily using UV-visible spectroscopy and fluorescence spectroscopy. We have observed that quantum dots with PEI exhibit slower growth and environmental factors such as temperature and light interaction do not play a significant impact on the growth kinetics of quantum dots with PEI as compared to quantum dots without PEI. To determine the cytotoxic effects of our synthesized ZnO quantum dots, human embryonic kidney (HEK) cells were used to monitor cell permeability and localization using fluorescent microscopy. Unfortunately, the HEK cells displayed apoptotic behavior as result of the ethanol used to synthesize our quantum dots. In the future, we plan to investigate synthesizing the ZnO quantum dots in more cytocompatible solvents. In addition, we plan to determine particle size using a dynamic light scattering instrument and studying their crystalline structure with X-ray diffraction.<br/>

Growth kinetics and cytotoxicity effects of surface modified zinc oxide quantum dots at room and cold temperatures using CsOH and NaOH

255th National Meeting (2018)

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