Highly luminescent and stable white light-emitting diodes created by direct incorporation of Cd-free quantum dots in silicone resins using the thiol group

We have fabricated highly luminescent and stable white light-emitting diodes (WLEDs) by directly incorporating CIS/ZnS quantum dots (QDs) into silicone resins using the thiol group. First, QD-containing phenyl-vinyl-oligosiloxane base resins were prepared by an in situ condensation reaction of sol-gel precursors and QDs with and without 3-(mercaptopropyl)trimethoxysilane. Next, base resins were cured with the crosslinker resin through hydrosilylation to fabricate QD-containing phenyl hybrimer (QDPH) resins. We found that the QDPH resin containing a thiol group exhibited higher transmittance and quantum efficiency than that without the thiol group because of more uniform dispersion of QDs. Finally, fabrication of WLEDs with the thiol-containing resin exhibited enhancements over that without the thiol group with regard to photo and thermal stabilities, color conversion and luminous efficiencies, and color accuracy. These enhancements were attributed to the stronger interaction between QDs and the polymer network through the thiol-anchoring group.