(14) Impact of Temperature and Solvent on Monolayer-Protected Quantum Dots

     Quantum dots (QDs) have been the focus of research efforts as they serve an efficient and less costly alternative for a host of applications, including digital displays and fluorescent biosensors. Water-soluble,... [ view full abstract ]

     Quantum dots (QDs) have been the focus of research efforts as they serve an efficient and less costly alternative for a host of applications, including digital displays and fluorescent biosensors. Water-soluble, monolayer-protected QDs are nanometer-sized crystals developed using semiconducting materials that exhibit quantum mechanical properties. The QDs studied were synthesized using several water-soluble thiols and alternative metal salts (e.g., cadmium acetate) at variable temperatures (-10 °C to 100 °C) to control their growth and study their solubility.  The optical properties of QD solutions were characterized using UV-visible and fluorescence spectroscopies.  Additionally, the QDs were purified and size-separated using size-exclusion chromatography (SEC) and their respective hydrodynamic radius was determined using pulsed field gradient (PFG) NMR.  The results demonstrated that QDs synthesized in organic solvents had a slower growth rate in comparison to QDs synthesized in water.  When QDs were synthesized in water, the QDs at higher temperatures grew faster than those at lower temperatures.