Quantum-dot-embedded colloidal polymeric particles for white light-emitting-diode with high color rendering index

We report on the simple colloidal encapsulation of quantum dots into polymeric microspheres using oil-in-water emulsions, which was generated by ultrasound emulsification method. Poly(styrene-co-methylmethacrylate) and Cd(S, Se) or CdSe@ZnS nanoparticles were dissolved in toluene and emulsified into water with surfactant. Then, oil phase inside emulsions was slowly evaporated producing composite microspheres of polymer and quantum dots. Their size could be controlled well by either varying the concentration of polymers in emulsion phase or adjusting the size of emulsion droplets. Finally, quantum-dot-embedded polymeric microspheres were deposited on the blue LED chips which showed white colors with high value of color rendering index.