This finding suggests possible ways of optimizing the charge separation yield and lifetime by controlling the thickness and nature of the shell materials. CdSe/ZnS Core-shell Quantum Dots CdSe/ZnS in Toluene. Coating CdSe bare quantum dots with a ZnS layer indicates an enhancement in the PL intensity. I would also like to thank my parents to allow me to study at Cranfield University. Her help and knowledge in the field have been vital to developing this thesis. iii ACKNOWLEDGEMENTS I would like to thank Iva Chianella who has supported me and guided me throughout the project.
The much steeper decrease in charge recombination rate results from a larger hole effective mass (than electron) in the ZnS shell. Core Shell Quantum Dot incorporating WKB approximation. FRET, Quantum dots, dye, fluorescence probes. Model calculations show that these trends can be attributed to the exponential decrease of the 1S electron and hole densities at the QD surface with the shell thickness. We show that the charge separation and recombination rates decrease exponentially with the shell thickness (d), k(d) = k(0)e(-βd), with exponential decay factors β of 0.35 ± 0.03 per Å and 0.91 ± 0.14 per Å, respectively. These kinetics are measured in CdSe/ZnS type I core/shell QDs adsorbed with anthroquinone molecules (as electron acceptor) by time-resolved transient absorption spectroscopy. Water Soluble Visible CdSe/ZnS Core/Shell Quantum Dots. Myron Rubenstein, Ph. To understand how the shell thickness affects the solar cell performance, its effects on interfacial charge separation and recombination kinetics are investigated. The following water soluble CuInZnS/ZnS core/shell Quantum Dots are in stock in the acid, amine, and diol coated forms. Type I core/shell quantum dots (QDs) have been shown to improve the stability and conversion efficiency of QD-sensitized solar cells compared to core only QDs.