Intensifying Light Emission in Composite Quantum Dot/Polymer Color-Conversion Films via Blue Light Redirection and Recycling with Dual-Size Polymer Beads

This paper provides new insights into the luminescence efficiency of quantum dot (QD)-polymer composites, highlighting that light scattering plays a more critical role than QD concentration for color conversion applications. In this study, polymer-based light scattering particles (LSPs) embedded in the QD/polymer film is served as effective scattering centers. Their effects are analyzed based on size, concentration, and refractive index (RI). The scattering behavior of the LSPs is characterized using diffuse transmittance (T_d) measurements and simulations of angular Mie-scattering patterns. Results reveal that LSPs of varying sizes predominantly influence forward and side scattering, directly affecting down-conversion events within the film. Increasing the concentration or RI of LSPs promotes backward scattering, which can attenuate incident light. By incorporating dual-sized LSPs into the QD/polymer films, light conversion efficiency (LCE) significantly improves. Initially, larger LSPs boost LCE to 160–170%, while the addition of smaller LSPs enhances side scattering, further elevating LCE to 193%.