Enhancing efficiency of quantum dot/photoresist nanocomposite using wrinkled silica-quantum dot hybrid particles

We have synthesized hybrid particles by embedding CdSe/ZnS quantum dots (QDs) into wrinkled silica nanoparticles. We found that increasing the QD loading decreased the quantum yield (QY) of the wrinkled silica-QD hybrid particles. Compared to the previously-reported silica-QD hybrid particles, the wrinkled silica-QD hybrid particles exhibited higher QY, because the QD surfaces were not chemically modified during the hybridization process. The hybrid particles and free QDs were then used to prepare QD/photoresist nanocomposites. Since photoresist resin contains non-solvent for QDs, nanocomposites containing free QDs showed noteworthy aggregation even at 1.5 wt%, which resulted in deteriorated efficiency and stability. However, we were able to fabricate QD/photoresist nanocomposites successfully using hybrid particles up to 30 wt%, as the wrinkled silica nanoparticles helped in the dispersion of the QDs. By varying the concentration of hybrid particles in the nanocomposites, we found that the hybrid particles at 20 wt% exhibited the highest quantum efficiency. Testing of wrinkled silica/photoresist nanocomposites (without QDs), fabricated with different concentrations of the wrinkled silica nanoparticles, revealed that the highest efficiency at 20 wt% hybrid particles was the result of enhanced scattering by the wrinkled silica nanoparticles. Finally, simple devices in which hybrid particles were placed on blue µ-LEDs were fabricated, and their luminescence properties were analyzed.