Convenient fabrication of composites with aqueous synthesized quantum dots for LED encapsulation

Organic approach is commercialized for fabrication of quantum dots (QDs) with the defects of high reagents expense, severe reaction conditions, toxic reaction residue etc. Although aqueous synthesis QDs has bad compatibility with common LEDs encapsulation material, like silicone and epoxy, it is relatively low cost, environmental friendly and simple. In this article, undoped and doped CdS were prepared through aqueous solution synthesis with 3-mercaptopropionic acid used as stabilizing agent. Convenient silica coating method was developed and mixed with silicone before curing since termination would occur when QDs were directly mixed with commercial silicone due to catalyst poisoning. Besides, quaternary ammonium salt was applied for fabricating QD-epoxy composite, which did not observe phase separation. The method is simple for acquiring the QDs without emission wavelength shift or quenching comparing with classical methods. The two methods can be guidances for assistance the development of LED with aqueous synthesized QDs.