Functional Z-Ligand Passivation for Photostable Barrier-Free Pixelated Quantum Dot Color Conversion Layers

Abstract

The practical application of quantum dot photoresists (QDPRs) for high-resolution displays is critically hindered by the insufficient passivation of surface anionic sites. Here, we report a surface modification strategy that integrates synergistic Z-type ligand zinc bis[2-(methacryloyloxy)ethyl] phosphate (Zn-BMEP) and zinc mono-2-(methacryloyloxy)ethyl succinate (Zn-MMES) to overcome these intrinsic limitations. The Z-type ligands selectively bind to anionic sites via phosphine-mediated surface reaction, forming a Zn-rich surface with hybrid MMES-BMEP groups that endow the QDs with both robust surface passivation and high solubility in photoresists and their solvents. The cured QDPRs achieve a high photoluminescence quantum yield of up to 87% and demonstrate remarkable photostability, with the red and green QDPR layers retaining over 90 and 83% of their initial emission intensity after 500 h of accelerated aging at 85 °C, even without air-barrier encapsulation. Photolithographic patterning of the QDPR yields high-resolution color conversion layers with 2 μm pixel size, excellent uniformity, and superior color performance. This surface engineering strategy resolves the trade-off between surface stability and photoresist compatibility, paving the way for stable, high-performance QDPRs in next-generation displays.