3-Dimensional Microlens Printing of Quantum Dot/Siloxane Hybrid Color-Converter for Highly Efficient and Stable...

Quantum dots (QDs) are promising color-converting materials for full-color micro-light-emitting diode (micro-LED) displays, but have poor stability and poor scalability, which hinder their practical application. We report a hybrid color-converting layer (CCL) composed of QDs, fumed silica nanoparticles (FSNs), and siloxane matrix that exhibits high optical performance and long-term stability under various environmental conditions. The QD-FSN/siloxane incorporates uniformly dispersed QDs within a siloxane matrix that is synthesized using an in situ sol-gel process. FSNs are used as scattering agents to increase the light diffusion and light extraction efficiency. They also serve as a thixotropic agent, which enables the achievement of dome-shaped 3D architecture by microdispensing. The solidified QD-FSN/siloxane films have excellent photoluminescent quantum yield (PLQY) due to scattering effects while maintaining extremely long stability in ambient air, chemical environments, high-temperature/high-humidity conditions, and continuous blue-light irradiation. We successfully fabricated dome-shaped microlens arrays (QD-FSN/siloxane-based CCLs), achieving natural white emission with high uniformity and a wide color gamut covering 110.4% of NTSC 1931 standard and 82.4% of Rec. 2020 standard. Finally, a full-color QD micro-LED device of 333 μm pixel pitch exhibits a 25.2% increase in luminous flux compared with blue micro-LED, showing the potential of QD-FSN/siloxane as an effective material for advanced micro-LED displays.