Research On The Synthesis Of Oil-Soluble CdSeS Alloyed Quantum Dots And Their Potential Application On White Light-emitting Diodes

Owing to their unique optical properties, Quantum Dots (QDs) haveattracted a lot of attention and potential applications in the biomedical,microelectronics and optoelectronic devices. In this thesis, we studied thesynthesis of CdSeS QDs and CdSeS/CdS/ZnS core/shel/shell QDs inparaffin liquid synthetic system instead of the traditional trioctylphosphineoxide (TOPO) synthetic system, and the application of the quantum dotson white light-emitting diodes (WLEDs). The main contributions are asfollows:(1) Phosphine-free synthesis of CdSeS alloyed QDs weresuccessfully realized in the paraffin liquid synthetic system. The effects ofthe reaction temperature, growth time, and the molar ratio of S and Se onthe properties of the CdSeS QDs were systematically investigated. Theas-prepared alloyed CdSeS QDs with a gradient “CdS-rich core/CdSe-richsurface” structure demonstrates their good optical stabilities following thephotobleaching and temperature change, which suggests their promisingapplication on photoelectric devices and biological fluorescent labeling.(2) CdSeS/CdS/ZnS core/shel/shell QDs were developed viacontinual precursor injection method in the paraffin liquid synthetic systemto further improve the stabilities of the CdSeS QDs. The optical propertiesof the core/shel/shell QDs possess was been enhanced and at the same timethe optical stabilities was been greatly improved, compared with theCdSeS core QDs, which indicates successful passivation of the CdS andZnS shell around the CdSeS core QDs. (3) The QDs were dispersed into the epoxy resin and formed a newtype of fluorescent composite to explore the potential application of QDsin WLED. After mixing green and red QDs with the epoxy resin, thecompositewas combined with a blue LED chipto obtain a WLED with highcolor rendering index (CRI). Besides, a “layered coating” was successfullydeveloped to avoid the self-absorption and reabsorption among the QDsvia, which revealed the potential application in WLED.