Polystyrene-Fiber-Rod Hybrid Composite Structure for Optical Enhancement in Quantum-Dot-Converted Light-Emitting Diodes

High-haze optical polymer diffusers have attracted great attention in terms of application in surface color-conversion films for lighting and displays. An optical diffuser based on polystyrene-fiber rods (PFRs) dispersed in polydimethylsiloxane (PDMS) resin is presented in this study. Using a simple electrospinning and emulsion shear fabrication process, composite films having optical diffusion properties were fabricated owing to index-mismatching between the PFRs and PDMS. During mechanical shearing, it is demonstrated that the rotation speed is the important parameter affecting the length of the PFRs. PFRs are uniformly dispersed in the PDMS matrix as an excellent filler to provide excellent light-scattering performance. The obtained composite films having low concentrations of PFRs (less than 1 wt %) exhibit highly efficient light diffusion in the visible-light region. At a 0.5 wt % PFR concentration, the composite film realizes a high haze of 87.4% while maintaining a high diffuse transmittance of 81.8% at 550 nm simultaneously. The PFRs were then filled in the quantum dot (QD) films for enhancing the photoluminescence (PL) intensity, thus demonstrating their light management ability. Compared to the reference, the PFRs/PDMS film with a 1 wt % concentration provides a 1.98 times PL intensity enhancement. While applying to the QD-based LEDs, the luminous flux of the QD-based LEDs exhibited the greatest improvement, demonstrating an enhancement of 11.37% at a 0.4 wt % PFR concentration. It exhibits potential for optical performance improvement in QD-based light-emitting diodes.