Alkyl-Functionalized ZnS Nanoparticles for Optical Management in Quantum Dot Color Conversion Layers with Inkjet Printing Compatibility

Achieving high color conversion efficiency by optimizing the optical properties of quantum dots (QDs) color conversion layers (CCLs) remains a challenge for next-generation display fabrication. CCLs, which convert blue light into red or green emission via photoluminescence, are key components in QD-based displays. However, their optical efficiency and inkjet printability remain limited due to poor compatibility between QDs and conventional light-scattering materials such as titanium oxide (TiO ₂ ). In this study, alkyl-functionalized ZnS nanoparticles were synthesized and incorporated into a QD ink formulation to enhance conversion efficiency and reduce blue leakage. The functionalized ZnS exhibited improved dispersibility in polymeric resins, ensuring uniform mixing. To enable precise inkjet-printed patterning, ink viscosity was optimized using a viscosity modifier, and substrate wettability was controlled via CF ₄ plasma treatment to confine ink droplets within defined areas. The results confirm that ZnS-enhanced QD CCLs improve color conversion efficiency (up to 78.1%) and reduce blue leakage below 1%, leading to superior optical performance. This study highlights the synergistic role of light-scattering nanoparticles and inkjet printability in enabling scalable, high-resolution inkjet-printed QD-CCLs, offering a promising approach for next-generation display technologies.