Fabrication of light emitting diodes using photo-patternable quantum dot-acrylate resins

We report the preparation of photo-patternable quantum dot (QD)-acrylate resins for application in light-emitting diodes (LEDs). To improve the dispersion of QDs in the acrylate monomer, methyl methacrylate (MMA), cyclohexyl methacrylate (CHMA) was added as a comonomer. Because of the hydrophobic interaction between the surfaces of the QDs and cyclohexyl groups of CHMA, and the presence of methacrylate groups in both MMA and CHMA, the dispersion of QDs in MMA was significantly improved. Then, by adding a photoinitiator and crosslinker into the mixture followed by UV curing, we successfully fabricated a QD-acrylate nanocomposite on a blue LED device. To determine the optimal resin composition, we varied the concentration of QDs and the concentration ratio of CHMA and MMA, and compared the transmittance, luminous efficacy, and color conversion efficiency of the resulting nanocomposites. The optimal composition for the photo-patternable resin was found to be 1 wt% QD and a CHMA : MMA ratio of 7 : 3. Finally, we demonstrated the successful fabrication of a white LED device with a high color accuracy and patterning of QD-acrylate resin using photolithography.